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Ipsilateral
Terms modified by Ipsilateral Selected AbstractsTransvenous Pacemaker Insertion Ipsilateral to Chronic Subclavian Vein Obstruction: An Operative Technique for Children and AdultsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2000MARC OVADIA OVADIA, M., et al.: Transvenous Pacemaker Insertion Ipsilateral to Chronic Subclavian Vein Obstruction: An Operative Technique for Children and Adults. Subclavian vein occlusion limits insertion of pacing electrodes in children and adults. The concern is greatest in children with a long-term need for pacing systems necessitating use of the contralateral vein and potential bilateral loss of access in the future. We describe an operative technique to provide ipsilateral access in chronic subclavian vein occlusion in five consecutive pediatric (n = 4, mean age 6.5 years) and adult (n = 1, age 70 with bilateral subclavian vein occlusion) patients in whom this condition was noted at the time of pacemaker or ICD implant. Occlusion was documented by venography. Pediatric cardiac diagnoses included complete heart block in all patients, tetralogy of Fallot in three, and L-transposition of the great vessels in one. Percutaneous brachiocephalic (innominate) or deep subclavian venous access was achieved by a supraclavicular approach using an 18-gauge Deseret angiocath, a Terumo Glidewire, and dilation to permit one or two 9,11 Fr sheaths. Electrode(s) were positioned in the heart and tunneled (pre, or retroclavicularly) to a pre, or retropectoral pocket. Pacemaker and ICD implants were successful in all without any complication of pneumothorax, arterial or nerve injury, or need for transfusion. Inadvertent arterial access did not occur as compared with prior infraclavicular attempts. One preclavicularly tunneled electrode dislodged with extreme exertion and was revised. Ipsilateral transvenous access for pacemaker or ICD is possible via a deep supraclavicular percutaneous approach when the subclavian venous obstruction is discovered at the time of implant. In children, it avoids the use of the contralateral vein that may be needed for future pacing systems in adulthood. This venous approach provides access large enough to allow even dual chamber pacing in children and can be accomplished safely. [source] Neural damage due to temporal lobe epilepsy: Dual-nuclei (proton and phosphorus) magnetic resonance spectroscopy studyPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 1 2004TAKAYUKI OBATA md Abstract, The aim of this study was to evaluate the usefulness of proton and phosphorus (1H and 31P) magnetic resonance spectroscopy (MRS) for temporal lobe epilepsy (TLE) patients, and to evaluate neural damage and metabolite dysfunction in the TLE patient brain. We performed 1H and 31P MRS of medial temporal lobes (MTL) in the same TLE patients (n = 14) with a relatively wide range of severity from almost seizure-free to intractable, and calculated the ratio of N-acetylasparate to choline-containing compounds and creatine + phosphocreatine (NAA/Cho + Cr) in 1H MRS and inorganic phosphate to all main peaks (%Pi) in 31P MRS. There was no significant correlation between NAA/(Cho + Cr) and %Pi ,in ,each ,side ,(ipsilateral, ,r = ,0.20; ,contralateral, ,r =,0.19). The values of NAA/(Cho + Cr) showed a significant difference between ipsilateral and contralateral MTLs to the focus of TLE patients (P < 0.01, paired t -test). Although %Pi also had a tendency to show the laterality of TLE, there was no significance. Ipsilateral (r = ,0.90, P < 0.0001) and contralateral (r = ,0.70, P < 0.005) NAA/(Cho + Cr) decreases and contralateral %Pi increase (r = 0.81, P < 0.001) had significant correlation with seizure frequency. 1H MRS provides more important information concerning neuronal dysfunction in MTL of TLE patients than 31P MRS. [source] Case of Pregnancy in Two Cows with Unicorn Horn of the Uterus either by Artificial Insemination at Ipsilateral or Embryo Transfer at Contralateral Corpus Luteum in the OvaryREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2008C Moriyama Contents Two Holstein heifers and a cow were diagnosed with White Heifer Disease by ultrasonography. Case 1 was a 14 month-old heifer with aplasia of both sides of the uterine horn. In case 2, a primiparous cow and case 3, an 18 month-old heifer, both showed aplasia of the right uterine horn. Case 2 became pregnant by artificial insemination at ipsilateral ovulatory follicle and corpus luteum in the left ovary, while case 3 became pregnant by embryo transfer at 7 days after oestrus with contralateral corpus luteum in the right ovary. [source] Spontaneous periictal leaving behavior: A potential lateralizing sign in mesial temporal lobe epilepsyEPILEPSIA, Issue 6 2009Liri Jin Summary Purpose:, Seizure-related spontaneous leaving behavior (LB) is an uncommonly reported phenomenon. The aim of this study was to determine its frequency, clinical significance, and especially its lateralizing value. Methods:, We analyzed retrospectively the spontaneous periictal LB occurring in complex partial seizures (CPS) of 138 patients with medically refractory mesial temporal lobe epilepsy (MTLE) with excellent postoperative seizure outcome and pathologic finding of hippocampal sclerosis. The relation of LB occurring in different phases of CPS to the side of resection was investigated. Results:, The overall frequency of periictal LB was 8.3% of 517 CPS and 25.2% of 123 patients. Among the 12 patients with ictal LB, 9 patients had epileptogenic focus ipsilateral to language dominant side, whereas the remaining 3 had seizure onset in the nondominant side. Conversely, 8 of 11 patients with postictal LB had foci in the nondominant side, and only three patients' seizures originated in the dominant side. Therefore, it was more likely for patients with left MTLE to show ictal LB and for those with right foci to display postictal LB (p = 0.03). Conclusions:, LB may represent a potential lateralizing sign. When LB occurs ictally, it may indicate seizure onset in the dominant temporal lobe, and LB occurring postictally indicates nondominant side seizure onset in patients with MTLE. [source] Decreased hippocampal volume on MRI is associated with increased extracellular glutamate in epilepsy patientsEPILEPSIA, Issue 8 2008Idil Cavus Summary Purpose: Temporal lobe epilepsy (TLE) is associated with smaller hippocampal volume and with elevated extracellular (EC) glutamate levels. We investigated the relationship between the hippocampal volume and glutamate in refractory TLE patients. Methods: We used quantitative MRI volumetrics to measure the hippocampal volume and zero-flow microdialysis to measure the interictal glutamate, glutamine, and GABA levels in the epileptogenic hippocampus of 17 patients with medication-resistant epilepsy undergoing intracranial EEG evaluation. The relationships between hippocampal volume, neurochemical levels, and relevant clinical factors were examined. Results: Increased EC glutamate in the epileptogenic hippocampus was significantly related to smaller ipsilateral (R2= 0.75, p < 0.0001), but not contralateral hippocampal volume when controlled for glutamine and GABA levels, and for clinical factors known to influence hippocampal volume. Glutamate in the atrophic hippocampus was significantly higher (p = 0.008, n = 9), with the threshold for hippocampal atrophy estimated as 5 ,M. GABA and glutamine levels in the atrophic and nonatrophic hippocampus were comparable. Decreased hippocampal volume was related to higher seizure frequency (p = 0.008), but not to disease duration or febrile seizure history. None of these clinical factors were related to the neurochemical levels. Conclusions: We provide evidence for a significant association between increased EC glutamate and decreased ipsilateral epileptogenic hippocampal volume in TLE. Future work will be needed to determine whether the increase in glutamate has a causal relationship with hippocampal atrophy, or whether another, yet unknown factor results in both. This work has implications for the understanding and treatment of epilepsy as well as other neurodegenerative disorders associated with hippocampal atrophy. [source] Prognostic Factors for the Surgery for Mesial Temporal Lobe Epilepsy: Longitudinal AnalysisEPILEPSIA, Issue 8 2005Sang-Wuk Jeong Summary:,Purpose: Determining long-term prognostic factors of surgery for mesial temporal lobe epilepsy (MTLE) is important for identifying ideal candidates and predicting the prognosis for individual patients. We tried to identify the prognostic factors of anterior temporal lobectomy (ATL) for MTLE with longitudinal multivariate analysis. Methods: Two hundred twenty-seven patients with MTLE were included in this study. The primary outcome variable was patient status 1,5 years after surgery: seizure free, or not. Clinical characteristics and recent diagnostic modalities were considered as prognostic factors. Univariate and standard multiple logistic-regression analysis for outcome at 1 and 5 years after surgery and the generalized estimation equation (GEE) model for longitudinal multiple logistic regression of the 5-year follow-up period were used. Results: The seizure-free rate at 1 year was 81.1% and decreased to 75.2% at 5 years after surgery. By the univariate or standard multiple logistic-regression analysis, age at surgery or hippocampal sclerosis on magnetic resonance imaging (MRI) ipsilateral to surgery was significant for the postsurgical outcome. However, the longitudinal analysis by the GEE model revealed that younger age at surgery [odds ratio (OR), 0.59; 95% confidence interval (CI), 0.43,0.81], absence of secondarily generalized tonic,clonic seizure (2°GTCS; OR, 0.45; 95% CI, 0.26,0.79), and hippocampal sclerosis on MRI (OR, 2.44; 95% CI, 1.11,5.26) were significant predictors of a good surgical outcome. Conclusions: Age at surgery, presence of 2°GTCS, and hippocampal sclerosis on MRI are independent prognostic factors for ATL in MTLE. These findings suggest that MTLE is a progressive disorder, and surgical outcome is better when early ATL is performed. [source] Functional MRI Predicts Memory Performance after Right Mesiotemporal Epilepsy SurgeryEPILEPSIA, Issue 2 2005Jozsef Janszky Summary:,Purpose: Anterior temporal lobe resection (ATR) is a treatment option in drug-resistant epilepsy. An important risk of ATR is loss of memory because mesiotemporal structures contribute substantially to memory function. We investigated whether memory-activated functional MRI (fMRI) can predict postoperative memory loss after anterior temporal lobectomy in right-sided medial temporal lobe epilepsy (MTLE). Methods: We included 16 patients (10 women) aged 16,54 years. The mean age at epilepsy onset was 12.5 years (range, 1,26 years). The patients' mean Wechsler IQ score was 95.2 (range, 62,125). The activation condition of fMRI consisted of retrieval from long-term memory induced by self-paced performance of an imaginative walk. All but one patient had left-sided speech dominance according to speech-activated fMRI. Outside the scanner, we evaluated the pre- and postoperative visual memory retention by using Rey Visual Design Learning Test. Results: We found a correlation between the preoperative asymmetry index of memory- fMRI and the change between pre- and postsurgical measures of memory retention. Reduced activation of the mesiotemporal region ipsilateral to the epileptogenic region correlated with a favorable memory outcome after right-sided ATR. Conclusions: In light of the postoperative results, the theoretical implication of our study is that fMRI based on a simple introspective retrieval task measures memory functions. The main clinical implication of our study is that memory- fMRI might replace the invasive Wada test in MTLE by using a simple fMRI paradigm. Predictive power, however, will be studied in larger patient samples. Other studies are required for left-sided MTLE and neocortical epilepsies to assess the clinical usefulness of memory- fMRI. [source] High-frequency Oscillations after Status Epilepticus: Epileptogenesis and Seizure GenesisEPILEPSIA, Issue 9 2004Anatol Bragin Summary:,Purpose: To investigate the temporal relation between high-frequency oscillations (HFOs) in the dentate gyrus and recurrent spontaneous seizures after intrahippocampal kainite-induced status epilepticus. Methods: Recording microelectrodes were implanted bilaterally in different regions of hippocampus and entorhinal cortex. A guide cannula for microinjection of kainic acid (KA) was implanted above the right posterior CA3 area of hippocampus. After recording baseline electrical activity, KA (0.4 ,g/0.2 ,l) was injected. Beginning on the next day, electrographic activity was recorded with video monitoring for seizures every day for 8 h/day for ,30 days. Results: Of the 26 rats studied, 19 revealed the appearance of sharp-wave activity and HFOs in the frequency range of 80 to 500 Hz in the dentate gyrus ipsilateral to the KA injection. In the remaining seven rats, no appreciable activity was noted in this frequency range. In some rats with recurrent seizures, HFOs were in the ripple frequency range (100,200 Hz); in others, HFOs were in the fast ripple frequency range (200,500 Hz), or a mixture of both oscillation frequencies was found. The time of detection of the first HFOs after status epilepticus varied between 1 and 30 days, with a mean of 6.3 ± 2.0 (SEM). Of the 19 rats in which HFO activity appeared, all later developed recurrent spontaneous seizures, whereas none of the rats without HFOs developed seizures. The sooner HFO activity was detected after status epilepticus, the sooner the first spontaneous seizure occurred. A significant inverse relation was found between the time to the first HFO detection and the subsequent rate of spontaneous seizures. Conclusions: A strong correlation was found between a decreased time to detection of HFOs and an increased rate of spontaneous seizures, as well as with a decrease in the duration of the latent period between KA injection and the detection of spontaneous seizures. Two types of HFOs were found after KA injection, one in the frequency range of 100 to 200 Hz, and the other, in the frequency range of 200 to 500 Hz, and both should be considered pathological, suggesting that both are epileptogenic. [source] A Short-echo-time Proton Magnetic Resonance Spectroscopic Imaging Study of Temporal Lobe EpilepsyEPILEPSIA, Issue 9 2002Robert J. Simister Summary: ,Purpose: We used short-echo-time proton magnetic resonance spectroscopy imaging (MRSI) to study metabolite concentration variation through the temporal lobe in patients with temporal lobe epilepsy (TLE) with and without abnormal MRI. Methods: MRSI was performed at TE = 30 ms to study 10 control subjects, 10 patients with TLE and unilateral hippocampal sclerosis, and 10 patients with TLE and unremarkable MRI (MRI negative). We measured the concentrations of N -acetyl aspartate +N -acetyl aspartyl-glutamate (NAAt), creatine (Cr), choline (Cho), glutamate + glutamine (Glx), and myoinositol, in the anterior, middle, and posterior medial temporal lobe (MTL), and in the posterior lateral temporal lobe. Segmented volumetric T1 -weighted MRIs gave the tissue composition of each MRSI voxel. Normal ranges were defined as the control mean ± 3 SD. Results: In the hippocampal sclerosis group, seven of 10 had abnormally low NAAt in the ipsilateral anterior MTL. In the MRI-negative group, four of 10 had low NAAt in the middle MTL voxel ipsilateral to seizure onset. Metabolite ratios were less sensitive to abnormality than was the NAAt concentration. Group analysis showed low NAAt, Cr, and Cho in the anterior MTL in hippocampal sclerosis. Glx was elevated in the anterior voxel contralateral to seizure onset in the MRI-negative group. Metabolite concentrations were influenced by voxel position and tissue composition. Conclusions: (a) Low NAAt, Cr, and Cho were features of the anterior sclerotic hippocampus, whereas low NAAt was observed in the MRI-negative group in the middle MTL region. The posterior temporal lobe regions were not associated with significant metabolite abnormality; (b) The two patient groups demonstrated different metabolite profiles across the temporal lobe, with elevated Glx a feature of the MRI-negative group; and (c) Voxel tissue composition and position influenced obtained metabolite concentrations. [source] Lateralizing and Localizing Values of Ictal Onset Recorded on the Scalp: Evidence from Simultaneous Recordings with Intracranial Foramen Ovale ElectrodesEPILEPSIA, Issue 11 2001G. Alarcón Summary: ,Purpose: The value of scalp recordings to localize and lateralize seizure onset in temporal lobe epilepsy has been assessed by comparing simultaneous scalp and intracranial foramen ovale (FO) recordings during presurgical assessment. The sensitivity of scalp recordings for detecting mesial temporal ictal onset has been compared with a "gold standard" provided by simultaneous deep intracranial FO recordings from the mesial aspect of the temporal lobe. As FO electrodes are introduced via anatomic holes, they provide a unique opportunity to record simultaneously from scalp and mesial temporal structures without disrupting the conducting properties of the brain coverings by burr holes and wounds, which can otherwise make simultaneous scalp and intracranial recordings unrepresentative of the habitual EEG. Methods: Simultaneous FO and scalp recordings from 314 seizures have been studied in 110 patients under telemetric presurgical assessment for temporal lobe epilepsy. Seizure onset was identified on scalp records while blind to recordings from FO electrodes and vice versa. Results: Bilateral onset (symmetric or asymmetric) was more commonly found in scalp than in FO recordings. The contrary was true for unilateral seizure onset. In seizures with bilateral asymmetric onset on the scalp, the topography of largest-amplitude scalp changes at onset does not have localizing or lateralizing value. However, 75,76% of seizures showing unilateral scalp onset with largest amplitude at T1/T2 or T3/T4 had mesial temporal onset. This proportion dropped to 42% among all seizures with a unilateral scalp onset at other locations. Of those seizures with unilateral onset on the scalp at T1/T2, 65.2% showed an ipsilateral mesial temporal onset, and 10.9% had scalp onset incorrectly lateralized with respect to the mesial temporal onset seen on FO recordings. In seizures with a unilateral onset on the scalp at electrodes other than T1/T2, the proportions of seizures with correctly and incorrectly lateralized mesial temporal onset were 37.5 and 4.2%, respectively. Thus the ratio between incorrectly and correctly lateralized mesial temporal onsets is largely similar for seizures with unilateral scalp onset at T1/T2 (16.7%) and for seizures with unilateral scalp onset at electrodes other than T1/T2 (11.2%). The onset of scalp changes before the onset of clinical manifestations is not associated with a lower proportion of seizures with bilateral onset on the scalp, or with a higher percentage of mesial temporal seizures or of mesial temporal seizures starting ipsilateral to the side of scalp onset. In contrast, the majority (78.4%) of mesial temporal seizures showed clinical manifestations starting after ictal onset on FO recordings. Conclusions: A bilateral scalp onset (symmetric or asymmetric) is compatible with a mesial temporal onset, and should not deter further surgical assessment. Although a unilateral scalp onset at T1/T2 or T3/T4 is associated with a higher probability of mesial temporal onset, a unilateral onset at other scalp electrodes does not exclude mesial temporal onset. A unilateral scalp onset at electrodes other than T1/T2 is less likely to be associated with mesial temporal onset, but its lateralizing value is similar to that of unilateral scalp onset at T1/T2. The presence of clinical manifestations preceding scalp onset does not reduce the localizing or lateralizing values of scalp recordings. [source] Ibotenate Injections into the Pre- and Parasubiculum Provide Partial Protection against Kainate-Induced Epileptic Damage in Layer III of Rat Entorhinal CortexEPILEPSIA, Issue 7 2001Tore Eid Summary: ,Purpose: A loss of neurons in layer III of the entorhinal cortex (EC) is often observed in patients with temporal lobe epilepsy and in animal models of the disorder. We hypothesized that the susceptibility of layer III of the EC to prolonged seizure activity might be mediated by excitatory afferents originating in the presubiculum. Methods: Experiments were designed to ablate the presubiculum unilaterally by focal ibotenate injections and to evaluate the effect of this deafferentation on the vulnerability of EC layer III neurons to the chemoconvulsant kainate (injected systemically 5 days later). Results: After treatment with kainate, 11 of the 15 rats preinjected with ibotenate showed clear-cut, partial neuroprotection in layer III of the EC ipsilateral to the ibotenate lesion. Serial reconstruction of the ibotenate-induced primary lesion revealed that entorhinal neurons were protected only in animals that had lesions in the pre- and parasubiculum, especially in the deep layers (IV,VI). Conclusions: The deep layers of the pre- and parasubiculum appear to control the seizure-induced damage of EC layer III. This phenomenon may be of relevance for epileptogenesis and for the pathogenesis of temporal lobe epilepsy. [source] Contralateral EEG Slowing and Amobarbital Distribution in Wada Test: An Intracarotid SPECT StudyEPILEPSIA, Issue 2 2000Seung Bong Hong Summary: Purpose: To relate the occurrence of contralateral electroencephalogram slowing (CES) to amobarbital distribution, we performed electroencephalogram (EEG) monitoring and intracarotid single photon emission computed tomography (SPECT) during an intracarotid amobarbital procedure (IAP). Methods: IAP was performed on 22 patients with temporal lobe epilepsy. CES was defined as the occurrence of significant EEG slowing on the contralateral hemisphere (>50% of the ipsilateral hemisphere slowing) after amobarbital injection. To map the distribution of the amobarbital, we injected a mixture of amobarbital and 99m technetium-ethylcysteinate dimer (99m Tc-ECD) into the internal carotid artery and performed a brain SPECT 2 h later. In the SPECT images, regions of interest were determined by ipsilateral and contralateral anterior cerebral artery territories (iACA, cACA), ipsilateral and contralateral middle cerebral artery territories (iMCA, cMCA), and ipsilateral and contralateral posterior cerebral artery territories (iPCA, cPCA), as well as ipsilateral and contralateral anterior and posterior mesial temporal regions (iAMT, cAMT, iPMT, cPMT). The perfusion of amobarbital was interpreted visually in each region. Results: Amobarbital was distributed in the iMCA in all the patients; in the iACA in 20 (90.9%) patients; in the iAMT in 14 (63.5%); and in the iPCA and iPMT in only two (9.1%). CES was observed in 13 (59.1%) patients. Cross-perfusion of amobarbital in limited areas of the cACA were observed in only four of 13 patients. Wada retention memory scores (WRMS) showed no significant difference between the CES- (n = 9) and CES+ (n = 13) groups. Conclusions: Amobarbital rarely perfused the iPCA territory and the iPMT region and was rarely delivered to the contralat-eral hemisphere. The occurrence of CES was not related to the cross-perfusion of amobarbital. CES appears to be produced by a transient functional disconnection from the ipsilateral hemisphere. [source] Pregnancy rates in mares after a single fixed time hysteroscopic insemination of low numbers of frozen-thawed spermatozoa onto the uterotubal junctionEQUINE VETERINARY JOURNAL, Issue 2 2003L. H. A. MORRIS Summary Reasons for performing study: To compensate for the wide variation in the freezability of stallion spermatozoa, it has become common veterinary practice to carry out repeated ultrasonography of the ovaries of oestrous mares in order to be able to inseminate them within 6,12 h of ovulation with a minimum of 300,500 × 106 frozen-thawed spermatozoa. Furthermore, in order to achieve satisfactory fertility, this requirement for relatively high numbers of spermatozoa currently limits our ability to exploit recently available artificial breeding technologies, such as sex-sorted semen, for which only 5,20 × 106 spermatozoa are available for insemination. Objectives: This study was designed to evaluate and compare the efficacy of hysteroscopic vs. conventional insemination when low numbers of spermatozoa are used at a single fixed time after administration of an ovulation-inducing agent. Methods: In the present study, pregnancy rates were compared in 86 mares inseminated once only with low numbers of frozen-thawed spermatozoa (3,14 × 106) at 32 h after treatment with human chorionic gonadotrophin (hCG), either conventionally into the body of the uterus or hysteroscopically by depositing a small volume of the inseminate directly onto the uterotubal papilla ipsilateral to the ovary containing the pre-ovulatory follicle. Results: Pregnancy rates were similarly high in mares inseminated conventionally or hysteroscopically with 14 × 106 motile frozen-thawed spermatozoa (67% vs. 64%). However, when the insemination dose was reduced to 3 × 106 spermatozoa, the pregnancy rate was significantly higher in the mares inseminated hysteroscopically onto the uterotubal junction compared to those inseminated into the uterine body (47 vs. 15%, P<0.05). Conclusions: When inseminating mares with <10 × 106 frozen-thawed stallion spermatozoa, hysteroscopic uterotubal junction deposition of the inseminate is the preferred method. Potential clinical relevance: Satisfactory pregnancy rates are achievable after insemination of mares with frozen-thawed semen from fertile stallions 32 h after administration of human chorionic gonadotrophin (Chorulon)1. Furthermore, these results were obtained when mares were inseminated with 14 × 106 progressively motile frozen-thawed spermatozoa from 2 stallions of proven fertility. [source] CLINICAL STUDY: Abnormalities in cortical and transcallosal inhibitory mechanisms in subjects at high risk for alcohol dependence: a TMS studyADDICTION BIOLOGY, Issue 3-4 2008Kesavan Muralidharan ABSTRACT Central nervous system (CNS) hyperexcitability and a resulting state of behavioral undercontrol are thought to underlie the vulnerability to early-onset alcohol dependence (AD). The aim of this study was to explore the differences in the functioning of cortical inhibitory systems, utilizing transcranial magnetic stimulation (TMS), in subjects at high risk (HR) and low risk (LR) for AD and to examine the relationship between CNS inhibition and behavioral undercontrol. Right-handed HR (n = 15) and LR (n = 15) subjects, matched for age, gender, height, weight and education, were assessed for psychopathology and family history of alcoholism using the Semi-Structured Assessment for the Genetics of Alcoholism and the Family Interview for Genetic Studies. Following single-pulse TMS, an electromyogram recorded from the right opponens pollicis muscle was used to measure the silent periods at different stimulus intensities. HR subjects had significantly shorter contralateral and ipsilateral (iSP) silent periods and a relatively higher prevalence of ,absent' iSP. They had significantly higher mean externalizing symptoms scores (ESS) than LR subjects, and there was a significant negative correlation between iSP duration and ESS. These preliminary findings suggest that HR subjects have relative impairments in corticocortical and transcallosal inhibitory mechanisms. The consequent state of CNS hyperexcitability may be etiologically linked to the excess of externalizing behaviors observed in this population, which is thought to be a predisposition to a higher risk of developing early-onset alcoholism. [source] Asymmetrical lateral ventricular enlargement in Parkinson's diseaseEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2009M. M. Lewis Background:, A recent case report suggested the presence of asymmetrical lateral ventricular enlargement associated with motor asymmetry in Parkinson's disease (PD). The current study explored these associations further. Methods:, Magnetic resonance imaging (3T) scans were obtained on 17 PD and 15 healthy control subjects at baseline and 12,43 months later. Baseline and longitudinal lateral ventricular volumetric changes were compared between contralateral and ipsilateral ventricles in PD subjects relative to symptom onset side and in controls relative to their dominant hand. Correlations between changes in ventricular volume and United Parkinson's disease rating scale motor scores (UPDRS-III) whilst on medication were determined. Results:, The lateral ventricle contralateral to symptom onset side displayed a faster rate of enlargement compared to the ipsilateral (P = 0.004) in PD subjects, with no such asymmetry detected (P = 0.312) in controls. There was a positive correlation between ventricular enlargement and worsening motor function assessed by UPDRS-III scores (r = 0.96, P < 0.001). Discussion:, There is asymmetrical lateral ventricular enlargement that is associated with PD motor asymmetry and progression. Further studies are warranted to investigate the underlying mechanism(s), as well as the potential of using volumetric measurements as a marker for PD progression. [source] Callosal contribution to ocular dominance in rat primary visual cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2010Chiara Cerri Abstract Ocular dominance (OD) plasticity triggered by monocular eyelid suture is a classic paradigm for studying experience-dependent changes in neural connectivity. Recently, rodents have become the most popular model for studies of OD plasticity. It is therefore important to determine how OD is determined in the rodent primary visual cortex. In particular, cortical cells receive considerable inputs from the contralateral hemisphere via callosal axons, but the role of these connections in controlling eye preference remains controversial. Here we have examined the role of callosal connections in binocularity of the visual cortex in naïve young rats. We recorded cortical responses evoked by stimulation of each eye before and after acute silencing, via stereotaxic tetrodotoxin (TTX) injection, of the lateral geniculate nucleus ipsilateral to the recording site. This protocol allowed us to isolate visual responses transmitted via the corpus callosum. Cortical binocularity was assessed by visual evoked potential (VEP) and single-unit recordings. We found that acute silencing of afferent geniculocortical input produced a very significant reduction in the contralateral-to-ipsilateral (C/I) VEP ratio, and a marked shift towards the ipsilateral eye in the OD distribution of cortical cells. Analysis of absolute strength of each eye indicated a dramatic decrease in contralateral eye responses following TTX, while those of the ipsilateral eye were reduced but maintained a more evident input. We conclude that callosal connections contribute to normal OD mainly by carrying visual input from the ipsilateral eye. These data have important implications for the interpretation of OD plasticity following alterations of visual experience. [source] Reorganization of cortical hand representation in congenital hemiplegiaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2009Yves Vandermeeren Abstract When damaged perinatally, as in congenital hemiplegia (CH), the corticospinal tract usually undergoes an extensive reorganization, such as the stabilization of normally transient projections to the ipsilateral spinal cord. Whether the reorganization of the corticospinal projections occurring in CH patients is also accompanied by a topographical rearrangement of the hand representations in the primary motor cortex (M1) remains unclear. To address this issue, we mapped, for both hands, the representation of the first dorsal interosseous muscle (1DI) in 12 CH patients by using transcranial magnetic stimulation co-registered onto individual three-dimensional magnetic resonance imaging; these maps were compared with those gathered in age-matched controls (n = 11). In the damaged hemisphere of CH patients, the representation of the paretic 1DI was either found in the hand knob of M1 (n = 5), shifted caudally (n = 5), or missing (n = 2). In the intact hemisphere of six CH patients, an additional, ipsilateral, representation of the paretic 1DI was found in the hand knob, where it overlapped exactly the representation of the non-paretic 1DI. In the other six CH patients, the ipsilateral representation of the paretic 1DI was either shifted caudally (n = 2) or was lacking (n = 4). Surprisingly, in these two subgroups of patients, the representation of the contralateral non-paretic 1DI was found in a more medio-dorsal position than in controls. The present study demonstrates that, besides the well-known reorganization of the corticospinal projections, early brain injuries may also lead to a topographical rearrangement of the representations of both the paretic and non-paretic hands in M1. [source] Prior pallidotomy reduces and modifies neuronal activity in the subthalamic nucleus of Parkinson's disease patientsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2008A. Zaidel Abstract Parkinson's disease (PD) patients with prior radio-frequency lesions in the internal segment of the globus pallidus (GPi, pallidotomy), whose symptoms have deteriorated, may be candidates for further invasive treatment such as subthalamic deep brain stimulation (STN DBS). Six patients with prior pallidotomy (five unilaterally; one bilaterally) underwent bilateral STN DBS. The microelectrode recordings (MERs, used intraoperatively for STN verification), ipsilateral and contralateral to pallidotomy, and MERs from 11 matched PD patients who underwent bilateral STN DBS without prior pallidotomy were compared. For each trajectory, average, variance and mean successive difference (MSD, a measure of irregularity) of the root mean square (RMS) of the STN MER were calculated. The RMS in trajectories ipsilateral to pallidotomy showed significant reduction of the mean average and MSD of STN activity when compared with trajectories from patients without prior pallidotomy. The RMS parameters contralateral to pallidotomy tend to lie between those ipsilateral to pallidotomy and those without prior pallidotomy. The average STN power spectral density of oscillatory activity was notably lower ipsilateral to pallidotomy than contralateral, or without prior pallidotomy. The finding that pallidotomy reduces STN activity and changes firing characteristics, in conjunction with the effectiveness of STN DBS despite prior pallidotomy, calls for reappraisal and modification of the current model of the basal ganglia (BG) cortical network. It highlights the critical role of direct projections from the BG to brain-stem structures and suggests a possible GPi,STN reciprocal positive-feedback mechanism. [source] Oxytocin injected into the ventral tegmental area induces penile erection and increases extracellular dopamine in the nucleus accumbens and paraventricular nucleus of the hypothalamus of male ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007Maria Rosaria Melis Abstract The neuropeptide oxytocin (20,100 ng), induces penile erection when injected unilaterally into the caudal but not rostral mesencephalic ventral tegmental area (VTA) of male Sprague,Dawley rats. Such pro-erectile effect started 30 min after treatment and was abolished by the prior injection of d(CH2)5Tyr(Me)2 -Orn8 -vasotocin (1 µg), an oxytocin receptor antagonist injected into the same caudal ventral tegmental area or of haloperidol (1 µg), a dopamine receptor antagonist, injected either into the nucleus accumbens shell (NAs) or into the paraventricular nucleus of the hypothalamus (PVN) ipsilateral to the injected ventral tegmental area. Penile erection was seen 15 min after the occurrence of, or concomitantly to, an increase in extracellular dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the dialysate obtained from the nucleus accumbens or the paraventricular nucleus, which was also abolished by d(CH2)5Tyr(Me)2 -Orn8 -vasotocin (1 µg), injected into the ventral tegmental area before oxytocin. In the caudal ventral tegmental area oxytocin-containing axons/fibres (originating from the paraventricular nucleus) appeared to closely contact cell bodies of mesolimbic dopaminergic neurons retrogradely labelled with Fluorogold injected into the nucleus accumbens shell, suggesting that oxytocin effects are mediated by the activation of mesolimbic dopaminergic neurons, followed in turn by that of incerto-hypothalamic dopaminergic neurons impinging on oxytocinergic neurons mediating penile erection. As the stimulation of paraventricular dopamine receptors not only induces penile erection, but also increases mesolimbic dopamine neurotransmission by activating oxytocinergic neurons, these results provide further support for the existence of a neural circuit in which dopamine and oxytocin influence both the consummatory and motivational/rewarding aspects of sexual behaviour. [source] Synaptic localization of GABAA receptor subunits in the substantia nigra of the rat: effects of quinolinic acid lesions of the striatumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2002Fumino Fujiyama Abstract The inhibitory amino acid, ,-aminobutyric acid (GABA), plays a critical role in the substantia nigra (SN) in health and disease. GABA transmission is controlled in part by the type(s) of GABA receptor expressed, their subunit composition and their location in relation to GABA release sites. In order to define the subcellular localization of GABAA receptors in the SN in normal and pathological conditions, sections of SN from control rats and rats that had received quinolinic acid lesions of the striatum were immunolabelled using the postembedding immunogold technique with antibodies against subunits of the GABAA receptor. Immunolabelling for ,1, ,2/3 and ,2 subunits was primarily located at symmetrical synapses. Double-labelling revealed that ,2/3 subunit-positive synapses were formed by terminals that were enriched in GABA. Colocalization of ,1, ,2/3 and ,2 subunits occurred at individual symmetrical synapses, some of which were identified as degenerating terminals derived from the striatum. In the SN ipsilateral to the striatal lesion there was a significant elevation of immunolabelling for ,2/3 subunits of the GABAA receptor at symmetrical synapses, but not of GluR2/3 subunits of the AMPA receptor at asymmetrical synapses. It was concluded that fast GABAA -mediated transmission occurs primarily at symmetrical synapses within the SN, that different receptor subunits coexist at individual synapses and that the upregulation of GABAA receptors following striatal lesions is expressed as increased receptor density at synapses. The upregulation of GABAA receptors in Huntington's disease and its models is thus likely to lead to an increased efficiency of transmission at intact GABAergic synapses in the SN and may partly underlie the motor abnormalities of this disorder. [source] Discharge patterns of neurons in the medial pontobulbar reticular formation during fictive mastication in the rabbitEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2001K.-G. Westberg Abstract In this study, we describe functional characteristics of neurons forming networks generating oral ingestive motor behaviours. Neurons in medial reticular nuclei on the right side of the brainstem between the trigeminal and hypoglossal motor nuclei were recorded in anaesthetized and paralysed rabbits during two types of masticatory-like motor patterns induced by electrical stimulation of the left (contralateral) or right (ipsilateral) cortical masticatory areas. Sixty-seven neurons in nucleus reticularis pontis caudalis (nPontc), nucleus reticularis parvocellularis (nParv), and nucleus reticularis gigantocellularis (Rgc) were studied. These were classified as phasic or tonic depending on their firing pattern during the fictive jaw movement cycle. Phasic neurons located in the dorsal part of nPontc were active during the jaw opening phase, whilst those in dorsal nParv tended to fire during the closing phase. In most neurons, burst duration and firing frequency changed between the two motor patterns, but there was little change in phase of firing. Tonic units were mainly recorded in the ventral half of nPontc, and at the junction between Rgc and caudal nParv. Cortical inputs with short latency from the contralateral masticatory area were more frequent in phasic (82%) than tonic (44%) neurons, whilst inputs from the ipsilateral cortex were equal in the two subgroups (57% and 56%). Phasic neurons had significantly shorter mean contralateral than ipsilateral cortical latencies, whilst there was no difference among tonic neurons. Intra- and perioral primary afferent inputs activated both types of neurons at oligo-synaptic latencies. Our results show that subpopulations of neurons in medial reticular nuclei extending from the caudal part of the trigeminal motor nucleus to the rostral third of the hypoglossal motor nucleus are active during the fictive masticatory motor behaviour. Unlike masticatory neurons in the lateral tegmentum, the medial subpopulations are spatially organized according to discharge pattern. [source] Glutamate transporter expression in astrocytes of the rat dentate gyrus following lesion of the entorhinal cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2001C. Hein Abstract The glutamate transporters GLT-1 and GLAST localized in astrocytes are essential in limiting transmitter signalling and restricting harmful receptor overstimulation. To show changes in the expression of both transporters following lesion of the entorhinal cortex (and degeneration of the glutamatergic tractus perforans), quantitative microscopic in situ hybridization (ISH) using alkaline-phosphatase-labelled oligonucleotide probes was applied to the outer molecular layer of the hippocampal dentate gyrus of rats (termination field of the tractus perforans). Four groups of rats were studied: sham-operated controls, and animals 3, 14 and 60 days following unilateral electrolytic lesion of the entorhinal cortex. The postlesional shrinkage of the terminal field of the perforant path, ipsilateral to the lesion side, was determined and considered in the evaluation of quantitative ISH data. Statistical analysis revealed that ipsilateral to the lesion side there was a significant decrease of the GLT-1 mRNA at every postlesional time-point and of the GLAST mRNA at 14 and 60 days postlesion. The maximal decrease was ,,45% for GLT-1 and ,,35% for GLAST. In the terminal field of the perforant path contralateral to the lesion side, no significant changes of ISH labelling were measured. The results were complemented by immunocytochemical data achieved using antibodies against synthetic GLT-1 and GLAST peptides. In accordance with ISH results, there was an obvious decrease of GLT-1 and GLAST immunostaining in the terminal field of the perforant path ipsilateral to the lesion side. From these data we conclude that, following a lesioning of the entorhinal cortex, the loss of glutamatergic synapses in the terminal field of the perforant path resulted in a strong downregulation of glutamate transporters in astrocytes. The decrease of synaptically released glutamate or of other neuronal factors could be involved in this downregulation. [source] Facial nerve injury-induced disinhibition in the primary motor cortices of both hemispheresEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2000Tamás Farkas Abstract Unilateral facial nerve transection induces plastic reorganization of the somatotopic order in the primary motor cortex area (MI). This process is biphasic and starts with a transient disinhibition of connections between cortical areas in both hemispheres. Little is known about the underlying mechanisms. Here, cortical excitability has been studied by paired pulse electrical stimulation, applied either within the MI or peripherally to the trigeminal nerve, while the responses were recorded bilaterally in the MI. The ratios between the amplitudes of the second and first evoked potentials (EPs or fEPSPs) were taken as measures of the inhibitory capacity in the MI ipsilateral or contralateral to the nerve injury. A skin wound or unilateral facial nerve exposure immediately caused a transient facilitation, which was followed by a reset to some level of inhibition in the MI on both sides. After facial nerve transection, the first relatively mild reduction of inhibition started shortly (within 10 min) after denervation. This was followed by a second step, involving a stronger decrease in inhibition, 40,45 min later. Previous publications have proved that sensory nerve injury (deafferentation) induces disinhibition in corresponding areas of the sensory cortex. It is now demonstrated that sham operation and, to an even greater extent, unilateral transection of the purely motoric facial nerve (deefferentation), each induce extended disinhibition in the MIs on both sides. [source] Repeated long-term potentiation induces mossy fibre sprouting and changes the sensibility of hippocampal granule cells to subconvulsive doses of pentylenetetrazolEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2000Hadir Hassan Abstract Electrical and chemical kindling induces sprouting of the mossy fibre system and potentiation of evoked field potentials in the dentate gyrus. It has been postulated that such changes may also be induced by repeated induction of long-term potentiation (LTP) with tetanic stimulation of the perforant pathway. LTP was induced in rats chronically implanted with stimulation electrodes in the ipsilateral and contralateral angular bundles and with a recording electrode in the ipsilateral dorsal dentate gyrus. The animals were stimulated 10 times on 10 consecutive days but with different tetanization strengths. Sprouting of the mossy fibres terminating in the CA3 region was significantly induced only in the group of ,strongly' tetanized animals, but not in that of ,weakly' tetanized animals, or in low-frequency stimulated animals. Additionally, a novel form of potentiation which was previously found in pentylenetetrazol (PTZ)-kindled animals was also observed in the group of ,strongly' and ,weakly' tetanized rats. Differences in duration of this potentiation were found between the two groups of animals tetanized with different strengths. The results further demonstrate that morphological and functional changes in the hippocampus, similar to those seen after kindling, can also occur in an activation paradigm leading to long-lasting synaptic plasticity but not accompanied by seizure activity. [source] Is central neck dissection necessary for the treatment of lateral cervical nodal recurrence of papillary thyroid carcinoma?HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 10 2007Jong-Lyel Roh MD Abstract Background: Although the pattern of cervical lymph node metastases from papillary thyroid carcinoma (PTC) has been described, little is known about the pattern of lateral cervical nodal recurrence. The aim of this study was to establish the optimal strategy for neck dissection in patients who underwent reoperation for lateral cervical recurrence of PTC. Methods: We reviewed the records of 22 patients who underwent neck dissection for lateral nodal recurrence of thyroid cancer between 2002 and 2004. Eight patients had thyroid remnants or recurrent tumors in the bed and 6 had undergone lateral neck dissection prior to referral. Patients underwent comprehensive dissection of the posterolateral and ipsilateral (n = 10) or bilateral (n = 12) central neck. The pattern of nodal recurrence and postoperative morbidity were analyzed. Results: All patients had lateral compartment involvement, 91% at mid-lower, 45% at upper, and 18% at posterior sites. Central nodes were involved in 86% of patients: 82% at ipsilateral paratracheal, 32% at pretracheal, 27% at superior mediastinal, and 2 patients at contralateral sites. Skip lateral recurrence with no positive central nodes was rarely observed (14%). Postoperative vocal cord palsy (n = 1) and hypoparathyroidism (n = 5) developed only in patients undergoing bilateral central compartment dissection. Conclusions: The inclusion of comprehensive ipsilateral central and lateral neck dissection in the reoperation for patients with lateral neck recurrence of PTC is an optimal surgical strategy. © 2007 Wiley Periodicals, Inc. Head Neck, 2007 [source] Coherent corticomuscular oscillations originate from primary motor cortex: Evidence from patients with early brain lesionsHUMAN BRAIN MAPPING, Issue 10 2006Christian Gerloff Abstract Coherent oscillations of neurons in the primary motor cortex (M1) have been shown to be involved in the corticospinal control of muscle activity. This interaction between M1 and muscle can be measured by the analysis of corticomuscular coherence in the ,-frequency range (,-CMCoh; 14,30 Hz). Largely based on magnetoencephalographic (MEG) source-modeling data, it is widely assumed that ,-CMCoh reflects direct coupling between M1 and muscle. Deafferentation is capable of modulating ,-CMCoh, however, and therefore the influence of reafferent somatosensory signaling and corresponding neuronal activity in the somatosensory cortex (S1) has been unclear. We present transcranial magnetic stimulation (TMS) and MEG data from three adult patients suffering from congenital hemiparesis due to pre- and perinatally acquired lesions of the pyramidal tract. In these patients, interhemispheric reorganization had resulted in relocation of M1 to the contralesional hemisphere, ipsilateral to the paretic hand, whereas S1 had remained in the lesioned hemisphere. This topographic dichotomy allowed for an unequivocal topographic differentiation of M1 and S1 with MEG (which is not possible if M1 and S1 are directly adjacent within one hemisphere). In all patients, ,-CMCoh originated from the contralesional M1, in accordance with the TMS-evoked motor responses, and in contrast to the somatosensory evoked fields (SEFs) for which the sources (N20m) were localized in S1 of the lesioned hemisphere. These data provide direct evidence for the concept that ,-CMCoh reflects the motorcortical efferent drive from M1 to the spinal motoneuron pool and muscle. No evidence was found for a relevant contribution of neuronal activity in S1 to ,-CMCoh. Hum Brain Mapp, 2006. © 2006 Wiley-Liss, Inc. [source] Temporal dynamics of ipsilateral and contralateral motor activity during voluntary finger movementHUMAN BRAIN MAPPING, Issue 1 2004Ming-Xiong Huang Abstract The role of motor activity ipsilateral to movement remains a matter of debate, due in part to discrepancies among studies in the localization of this activity, when observed, and uncertainty about its time course. The present study used magnetoencephalography (MEG) to investigate the spatial localization and temporal dynamics of contralateral and ipsilateral motor activity during the preparation of unilateral finger movements. Eight right-handed normal subjects carried out self-paced finger-lifting movements with either their dominant or nondominant hand during MEG recordings. The Multi-Start Spatial Temporal multi-dipole method was used to analyze MEG responses recorded during the movement preparation and early execution stage (,800 msec to +30 msec) of movement. Three sources were localized consistently, including a source in the contralateral primary motor area (M1) and in the supplementary motor area (SMA). A third source ipsilateral to movement was located significantly anterior, inferior, and lateral to M1, in the premotor area (PMA) (Brodmann area [BA] 6). Peak latency of the SMA and the ipsilateral PMA sources significantly preceded the peak latency of the contralateral M1 source by 60 msec and 52 msec, respectively. Peak dipole strengths of both the SMA and ipsilateral PMA sources were significantly weaker than was the contralateral M1 source, but did not differ from each other. Altogether, the results indicated that the ipsilateral motor activity was associated with premotor function, rather than activity in M1. The time courses of activation in SMA and ipsilateral PMA were consistent with their purported roles in planning movements. Hum. Brain Mapp. 23:26,39, 2004. © 2004 Wiley-Liss, Inc. [source] Cortical Indexes of Saccade Planning Following Covert Orienting in 20-Week-Old InfantsINFANCY, Issue 2 2001John E. Richards This study examined scalp-recorded, event-related potential (ERP) indexes of saccade planning in 20-week-old infants. A spatial cuing procedure was used in which the infants were presented with a central fixation stimulus and a peripheral cue. A peripheral target followed the cue on the ipsilateral or contralateral side of the cue. The procedure resulted in covert orienting of attention in these participants, reflected in behavioral (e.g., response facilitation or inhibition of return depending on cue-target stimulus-onset asynchrony) and ERP (P1 facilitation to ipsilateral target) indexes of covert orienting of attention. A presaccadic ERP that occurred over the frontal cortex about 50 msec before the saccade onset was largest when the saccade was to a target in a cued location. A presaccadic ERP potential that occurred about 300 msec before the saccade onset was largest for the saccades toward the cued location whether the target was present or not. These results suggest that saccade planning occurs in infants at this age and that infant saccade planning is controlled by cortical systems. [source] The Blalock-Taussig ShuntJOURNAL OF CARDIAC SURGERY, Issue 2 2009Shi-Min Yuan M.D. This warrants us a zest in making a comprehensive survey on this subject. Methods: Articles were extensively retrieved from the MEDLINE database of National Library of Medicine USA if the abstract contained information relevant to the B-T shunt in terms of the conduit options, modified surgical techniques, surgical indications, short- and long-term results, complications, and prognosis. Further retrieval was undertaken by manually searching the reference list of relevant papers. Results: Classical or modified B-T shunts, either on ipsilateral or contralateral side to the aortic arch, can be performed on patients of any age with minimum postoperative complications and low operative mortality. Expended polytetrafluoroethylene has gained satisfactory long-term patency rate in the construction of the modified B-T shunt. Excellent pulmonary artery growth was observed in the patients with a modified B-T shunt, and it has shown superb prognosis over the classic with regard to hemodynamics, patency rate, and survival. Conclusions: The modified B-T shunt that was developed on basis of the classic fashion remains the preferable palliative procedure aiming at enhancing pulmonary blood flow for neonates and infants with complicated cyanotic congenital heart defects. The modified B-T shunt is technically simpler with less dissection, and blood flow to the respective arm is not jeopardized. It has been proved to be of low risk, excellent palliation, and is associated with excellent pulmonary artery growth, has become the most effective palliative shunt procedure of today. [source] Maintenance of Atrial Fibrillation by Pulmonary Vein Tachycardia with Ostial Conduction Block: Evidence of an Interpulmonary Vein Electrical ConnectionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2008SEIICHIRO MATSUO M.D. We report a case of a 56-year-old man with paroxysmal atrial fibrillation who underwent segmental, ostial pulmonary vein (PV) isolation while in arrhythmia. During isolation of the left superior PV (LSPV), organized electrical activity was seen within the vein, suggestive of a PV tachycardia with a cycle length of 90 ms. Simultaneously, organized electrical activity with a cycle length of 180 ms was seen in the left inferior PV (LIPV), suggestive of 2:1 conduction between the LSPV and the LIPV. Isolation of the LIPV resulted in conversion to sinus rhythm, while confirming isolation of the LSPV by the presence of ongoing PV tachycardia in this vein. This case demonstrates a direct electrical connection between the ipsilateral left PVs, leading to maintenance of atrial fibrillation. [source] | |||||||||||||||||||||||||||||||