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Cardiac Arrhythmias (cardiac + arrhythmias)
Selected AbstractsMigraine Following Trans-Septal Access for Catheter Ablation of Cardiac ArrhythmiasHEADACHE, Issue 7 2009Palaniappan Saravanan MD There is increasing recognition that migraine with aura may be associated with intra-cardiac shunting because of a patent foramen ovale. Radio-frequency ablation to treat cardiac arrhythmias is an increasingly popular means of treating cardiac arrhythmias. Trans-septal puncture is routinely performed to gain access to the left atrium in order to ablate arrhythmias originating in the left heart. We report several cases of migraine triggered acutely by trans-septal puncture at our center. [source] The Diagnosis of Cardiac Arrhythmias: A Prospective Multi-Center Randomized Study Comparing Mobile Cardiac Outpatient Telemetry Versus Standard Loop Event MonitoringJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2007STEVEN A. ROTHMAN M.D. Introduction: Ambulatory electrocardiographic monitoring systems are frequently used in the outpatient evaluation of symptoms suggestive of a cardiac arrhythmia; however, they have a low yield in the identification of clinically significant but infrequent, brief, and/or intermittently symptomatic arrhythmias. The purpose of this study was to compare the relative value of a mobile cardiac outpatient telemetry system (MCOT) with a patient-activated external looping event monitor (LOOP) for symptoms thought to be due to an arrhythmia. Methods and Results: The study was a 17-center prospective clinical trial with patients randomized to either LOOP or MCOT for up to 30 days. Subjects with symptoms of syncope, presyncope, or severe palpitations who had a nondiagnostic 24-hour Holter monitor were randomized. The primary endpoint was the confirmation or exclusion of a probable arrhythmic cause of their symptoms. A total of 266 patients who completed the monitoring period were analyzed. A diagnosis was made in 88% of MCOT subjects compared with 75% of LOOP subjects (P = 0.008). In a subgroup of patients presenting with syncope or presyncope, a diagnosis was made in 89% of MCOT subjects versus 69% of LOOP subjects (P = 0.008). MCOT was superior in confirming the diagnosis of clinical significant arrhythmias, detecting such events in 55 of 134 patients (41%) compared with 19 of 132 patients (15%) in the LOOP group (P < 0.001). Conclusions: MCOT provided a significantly higher yield than standard cardiac loop recorders in patients with symptoms suggestive of a significant cardiac arrhythmia. [source] Evolution of Mapping and Anatomic Imaging of Cardiac ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2004DOUGLAS L. PACKER M.D. First page of article [source] Somatic Gene Transfer and Cardiac Arrhythmias:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2003Problems, Prospects First page of article [source] Feasibility of Spinal Cord Stimulation in Angina Pectoris in Patients with Chronic Pacemaker Treatment for Cardiac ArrhythmiasPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2003OLOF EKRE Spinal cord stimulation (SCS) has been used since 1985 as additional symptom-relieving treatment for patients with severe angina pectoris despite optimal conventional medical and invasive treatment. SCS has antiischemic effects and is safe and effective in long-term use. Several patients with coronary artery disease also suffer from disorders that necessitate the use of a cardiac permanent pacemaker (PPM). The combination of SCS and PPM has previously been considered hazardous because of possible false inhibition of the PPM. To assess if thoracic SCS and PPM can be safely combined in patients with refractory angina pectoris, 18 patients treated with both SCS and PPM were tested. The PPM settings were temporarily modified to increase the probability of interference, while the SCS intensity (used in bipolar mode) was increased to the maximum level tolerated by the patient. Any sign of inhibition of the ventricular pacing was recorded by continuous ECG monitoring. With the aid of a questionnaire, symptoms of interference during long-term treatment were evaluated. No patient had signs of inhibition during the tests. Reprogramming of the pacemaker because of the test results was not needed in any of the patients. The long-term follow-up data revealed no serious events. This study indicates that bipolar SCS and PPM can be safely combined in patients with refractory angina pectoris. However, individual testing is mandatory to ascertain safety in each patient. A testing procedure for patients in need of SCS and PPM is suggested in this article. (PACE 2003; 26:2134,2141) [source] Cardiac Arrhythmias Triggered by Sudden and Dynamic EffortsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010Emanuel C. Furtado M.D. Background: Some arrhythmias are triggered only during exercise. The aim of this study is to describe the frequency and type of arrhythmia induced by a standardized protocol of sudden and dynamic exercise, which tends to reflect routine situations of efforts (e.g., climbing stairs), and compare with those found on maximal cardiopulmonary exercise test (CPET). Methods: A total of 2329 subjects (1594 men) aged 9,91 years (mean 52 years, SD ± 16) were submitted to a standardized protocol of sudden and dynamic exercise (4-second exercise test [4sET]) prior to a CPET. A continuous digital electrocardiogram (ECG) was recorded during 4sET and CPET, and later reviewed and interpreted by the same physician (who supervised all the procedures). Results: A total of 1125 subjects (43%) had cardiac arrhythmias during one or both procedures. About 57% of the arrhythmias were supraventricular, but 47 subjects (2% of all subjects) presented more complex arrhythmias including 43 cases of nonsustained supraventricular tachycardia and four nonsustained ventricular tachycardia. While arrhythmias were more often exposed by the CPET (P < 0.01), in 221 cases (10% of the total sample) of arrhythmias they were only induced by 4sET; these included four cases of nonsustained supraventricular tachycardia. Conclusion: 4sET-induced arrhythmias tend to be simple and were always short-lasting. In some cases, ECG recording during 4sET showed arrhythmias that would not be induced by a progressive maximal exercise test. Different situations of exercise, sudden and short versus maximal and progressive, tend to generate different arrhythmic responses and possibly complementary clinical implications. Ann Noninvasive Electrocardiol 2010;15(2):151,156 [source] Evaluation of the Relationship between Atrial Septal Aneurysm and Cardiac Arrhythmias via P-Wave Dispersion and Signal-Averaged P-Wave DurationANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010Onur Sinan Deveci M.D. Objective: The aim of the study was to investigate the relationship between atrial septal aneurysms (ASAs) and cardiac arrhythmias via signal-averaged P-wave duration (SAPWD) and P-wave dispersion (Pd). Methods: Sixty-six patients with ASA served as the study group (group 1; 28 men and 38 women; mean age, 34 ± 10 years) and 62 healthy volunteers served as the control group (group 2; 29 men and 33 women; mean age, 31 ± 8 years) in the current study. ASAs were diagnosed by transthoracic echocardiography based on the criteria of a minimal aneurysmal base of ,15 mm; and an excursion of ,10 mm. All subjects were evaluated by 24-hour Holter monitoring, 12 lead body surface electrocardiogram for P-wave analysis, and signal-averaged electrocardiogram for P-wave duration (PWD). Results: There was no significant difference between the study and control groups in terms of age, gender, left atrium diameter, and left ventricular ejection fraction. Supraventricular arrhythmias (SVAs) were detected in 29 patients with ASA (43.9%) and 5 controls (8.1%; P < 0.001). The mean Pd in patients with ASA was significantly longer compared to the control group (14.1 ± 8 ms vs 7.0 ± 2.9 ms; P < 0.001). Similarly, the mean SAPWD in group 1 was significantly longer compared to group 2 (127.4 ± 17.6 ms vs 99.8 ± 12.3 ms; P < 0.001). Conclusion: Prolonged SAPWD and Pd were determined to indicate electrical disturbances in the atrial myocardium, and predict the increase in the prevalence of SVA in patients with ASA. Ann Noninvasive Electrocardiol 2010;15(2):157,164 [source] Bradycardia and sinus arrest during percutaneous ethanol injection therapy for hepatocellular carcinomaEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2004A. Ferlitsch Abstract Background, Percutaneous ethanol injection (PEI) is an established method in the treatment of hepatocellular carcinoma (HCC) and considered a safe procedure, with severe complications occurring rarely. Cardiac arrhythmias have not been reported to date. Aim of the study was to investigate the occurrence of dysrhythmias during PEI. Patients and methods, Twenty-six consecutive patients with inoperable HCC were included. During ultrasound-guided PEI with 95% ethanol, electrocardiogram (ECG) monitoring was performed before starting and continuously during PEI. Results, During PEI a significant reduction in mean heart rate (> 20%) was seen in 15 of 26 (58%) patients. In 11 of 26 patients (42%) occurrence of sinuatrial block (SAB) or atrioventricular block (AVB) was observed after a median time of 9 s (range 4,50) from the start of PEI with a median length of 24 s (range 12,480). Clinical symptoms were seen in two patients, including episodes of unconsciousness, seizure-like symptoms in both and a respiratory arrest during PEI in one patient, requiring mechanical ventilation. In four of 12 patients with repeat interventions, dysrhythmias were reproducible during monthly performed procedures. There was a significant association between the occurrence of SAB or AVB and the amount of instilled alcohol (P = 0·03) and post-PEI serum ethanol levels (P = 0·03). Conclusions, Bradycardia and block formation occur frequently during PEI. These symptoms could be explained by a vasovagal reaction and/or the direct effect of ethanol on the sinus node or the right atrial conduction system. Ethanol dose is an important factor for the occurrence of SAB/AVB. ECG-monitoring seems mandatory during PEI. Prophylactic use of intravenously administered Atropine might be useful. [source] Effect of acetate-free biofiltration with a potassium-profiled dialysate on the control of cardiac arrhythmias in patients at risk: A pilot studyHEMODIALYSIS INTERNATIONAL, Issue 1 2008Rosa I. MUÑOZ Abstract Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia. [source] QTc-interval abnormalities in a forensic populationCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 2 2007Sobhi Girgis Background,Antipsychotic drugs have been linked to sudden death among psychiatric patients, with a suggestion that prolongation of the QT-interval detectable on a standard electrocardiogram may be linked to fatal cardiac arrhythmias in these circumstances. Patients in secure forensic psychiatric facilities may be particularly likely to be on high-dose antipsychotic medication, and yet, as far as the authors are aware, no study of QT-intervals among such patients has been reported. Aim,To investigate the prevalence of QT-interval abnormalities and associated known risk factors for fatal cardiac arrhythmias in a sample of forensic patients. Method,Participants had a 12-lead electrocardiogram taken at 50 mm/s. Information was collected on their age, gender, psychiatric diagnosis, history of cardiovascular, liver and kidney diseases, and smoking, on all medications and on history of seclusion over the previous 12 months. Analysis was carried out using binary logistic regression. Results,Lower rates of QT-interval abnormalities than might be expected for this population were found. It was also found that a high dose of antipsychotics was associated with QTc prolongation (Adjusted OR = 9.5, 95% CI 2.6,34.2), a result consistent with previous literature. Conclusion,Forensic patients need not be at increased risk of QTc abnormality provided risk factors are properly managed. A high dose of antipsychotic medication increases the risk of QTc prolongation. Copyright © 2007 John Wiley & Sons, Ltd. [source] Torsade de pointes in a patient with complex medical and psychiatric conditions receiving low-dose quetiapineACTA PSYCHIATRICA SCANDINAVICA, Issue 4 2005W. V. R. Vieweg Objective:, Describe potential cardiac complications of low-dose quetiapine and other atypical antipsychotic drugs. Method:, We present a case report of a 45-year-old Black woman with multiple medical and psychiatric problems taking low-dose quetiapine. Results:, Coincident with a generalized seizure, the patient developed ,ventricular fibrillation'. She was countershocked with restoration of normal sinus rhythm. The initial electrocardiogram showed QT interval prolongation. Shortly thereafter, classical torsade de pointes appeared, lasted 10 min, and resolved spontaneously. Hypomagnesemia was present. A cardiac electrophysiologist was concerned that the very slow shortening of the prolonged QTc interval after magnesium replacement implicated quetiapine as a risk factor for QTc interval prolongation and torsade de pointes. A psychosomatic medicine consultant asserted that the fragmented medical and psychiatric care almost certainly contributed to the patient's medical problems. We discuss other cases of QT interval prolongation by newer antipsychotic drugs and previous reports by our group concerning the association of psychotropic drugs, QT interval prolongation, and torsade de pointes. Conclusion:, Atypical antipsychotic drug administration, when accompanied by risk factors, may contribute to cardiac arrhythmias including torsade de pointes. [source] QT interval prolongation in association with impaired circadian variation of blood pressure and heart rate in adolescents with Type 1 diabetesDIABETIC MEDICINE, Issue 11 2007K. Karavanaki Abstract Aims, The aim of our study was to assess diurnal blood pressure (BP) and heart rate variability and their possible relationship to the duration of the QT interval in adolescents with Type 1 diabetes. Methods, In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (± sd) age of 17.3 (± 4.1) years and a mean (± sd) diabetes duration of 8.5 (± 3.3) years, 24-h ambulatory BP was recorded. In addition, 24-h heart rate (HR) monitoring was performed and QT and corrected QT (QTc) intervals were estimated as indices of autonomic function. The patients were divided into two groups according to the absence of a decrease (non-dippers) or the presence of a decrease (dippers) in nocturnal diastolic BP (DBP). Results, In comparison with the dippers, the non-dippers showed reduced mean 24-h HR (79.6 vs. 84.0 beats/min, P = 0.05) and reduced mean daytime HR (81.3 vs. 86.0 beats/min, P = 0.05). The QT interval was prolonged in the non-dippers (366.3 vs. 347.5 ms, P = 0.015), and end systolic (28.7 vs. 25.9 mm, P = 0.004) and end diastolic left ventricular diameters (47.8 vs. 45.5 mm, P = 0.037) were greater. In stepwise multiple regression, HR variables were the most important factors affecting DBP ratio or the duration of the QT interval. Conclusions, In conclusion, normotensive diabetic adolescents with impaired nocturnal BP reduction also have impaired autonomic function tests, in association with prolonged QT interval and increased left ventricular diameters. These findings suggest that diabetic adolescents who have the ,non-dipper' phenomenon may need close follow-up for the possible development of vascular complications, such as cardiac arrhythmias and left-ventricular hypertrophy. [source] Pharmacogenomics in Cardiovascular MedicineDRUG DEVELOPMENT RESEARCH, Issue 3 2004John F. Carlquist Abstract The completion of the Human Genome Project (HGP) holds promise for further insight into how genetic differences contribute to an individual's response to a medicine(s). Even before the completion of the HGP, cardiovascular medicine was thrust into the arena of pharmacogenomics by the observation that many drugs, cardiovascular and noncardiovascular, promote cardiac arrhythmias. It is now recognized that these adverse responses as well as beneficial responses to cardiovascular medicines can be influenced by alterations in the genes for metabolizing enzymes, drug transporters, and drug targets. To the present, much basic information regarding gene,drug interactions has accumulated, but translation to clinical care has been slow. It is anticipated that the pace of clinical cardiovascular pharmacogenomics will increase as the result of better-designed studies and technological advances. The final adoption of this area of investigation into clinical practice will also be influenced by financial, psychosocial, and legal factors. Drug Dev. Res. 62:180,190, 2004. © 2004 Wiley-Liss, Inc. [source] Risk Factors in Sudden Death in Epilepsy (SUDEP): The Quest for MechanismsEPILEPSIA, Issue 5 2007Lina Nashef Summary:, People with epilepsy may die suddenly and unexpectedly without a structural pathological cause. Most SUDEP cases are likely to be related to seizures. SUDEP incidence varies and is <1:1,000 person-years among prevalent cases in the community and ,1:250 person years in specialist centres. Case,control studies identified certain risk factors, some potentially amenable to manipulation, including uncontrolled convulsive seizures and factors relating to treatment and supervision. Both respiratory and cardiac mechanisms are important. The apparent protective effect of lay supervision supports an important role for respiratory factors, in part amenable to intervention by simple measures. Whereas malignant tachyarrhythmias are rare during seizures, sinus bradycardia/arrest, although infrequent, is well documented. Both types of arrhythmias can have a genetic basis. This article reviews SUDEP and explores the potential of coexisting liability to cardiac arrhythmias as a contributory factor, while acknowledging that at present, bridging evidence between cardiac inherited gene determinants and SUDEP is lacking. [source] Heart Rate Changes and ECG Abnormalities During Epileptic Seizures: Prevalence and Definition of an Objective Clinical SignEPILEPSIA, Issue 8 2002Maeike Zijlmans Summary: ,Purpose: To determine the prevalence of heart rate changes and ECG abnormalities during epileptic seizures and to determine the timing of heart rate changes compared to the first electrographic and clinical signs. To assess the risk factors for the occurrence of ECG abnormalities. Methods: We analyzed retrospectively 281 seizures in 81 patients with intractable epilepsy who had prolonged video-EEG and two-channel ECG. The nature and timing of heart rate changes compared to the electrographic and clinical seizure onset was determined. The ictal period (including one minute preictally and three minutes postictally) was analyzed for cardiac arrhythmias, conduction and repolarization abnormalities. Risk factors for cardiac abnormalities were investigated using parametric and non-parametric statistics. Results: There was an increase in heart rate of at least 10 beats/minute in 73% of seizures (93% of patients) and this occurred most often around seizure onset. In 23% of seizures (49% of patients) the rate increase preceded both the electrographic and the clinical onset. ECG abnormalities were found in 26% of seizures (44% of patients). One patient had an asystole for 30 seconds. Long seizure duration increased the occurrence of ECG abnormalities. No other risk factor was found. Conclusions: Heart rate changes occur frequently and occur around the time or even before the earliest electrographic or clinical change. The change can clarify the timing of seizure onset and the specific rate pattern may be useful for seizure diagnosis and for automatic seizure detection. ECG abnormalities occur often and repeatedly in several seizures of the same patient. [source] Reversal of cardiac complications in thalassemia major by long-term intermittent daily intensive iron chelationEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2003H. Miskin Abstract: Objectives: In patients with thalassemia major (TM) who are non-compliant with long-term deferoxamine (DFO) chelation, survival is limited mainly because of cardiac complications of transfusional siderosis. It was recently shown in a small group of TM patients with established cardiac damage that continuous 24-h DFO infusion via an indwelling intravenous (i.v.) catheter is effective in reversing cardiac toxicity. The aim of the present study was to evaluate the results with intermittent daily (8,10 h) i.v. DFO. Patients: Eight TM patients with cardiac complications treated with intensive intermittent DFO were retrospectively evaluated by the mean annual serum ferritin, radionucleated ventriculography and 24-h electrocardiography recordings. Results: The median age at diagnosis of cardiac disease was 17.5 yr (range 14,21), and the median follow-up time was 84 months (range, 36,120). In the majority of patients (seven of eight) high-dose DFO (mean 95 ± 18.3 mg/kg/d) was administered via a central venous line. During follow-up, there was a significant decrease in the mean ferritin levels (5828 ± 2016 ng/mL to 1585 ± 1849 ng/mL, P < 0.001). Both cardiac failure (mean ejection fraction 32 ± 5) and cardiac arrhythmias were resolved in four of five patients. One non-compliant patient died during the follow-up. Following discontinuation of the i.v. therapy, compliance with conventional DFO therapy improved. The complications of this regimen, mainly catheter-related infections and catheter-related thrombosis, were similar to those described earlier. Conclusions: These results with the longest follow-up period in the literature suggest that i.v. high-dose DFO for 8,10 h daily may be as effective as continuous 24-h infusion for the reversal of established cardiac disease in TM. [source] Chamber-specific effects of hypokalaemia on ventricular arrhythmogenicity in isolated, perfused guinea-pig heartEXPERIMENTAL PHYSIOLOGY, Issue 4 2009Oleg E. Osadchii Diuretic-induced hypokalaemia has been shown to promote cardiac arrhythmias in hypertensive patients. The present study was designed to determine whether hypokalaemia increases arrhythmic susceptibility of the left ventricle (LV) or the right ventricle (RV), or both. Proarrhythmic effects of hypokalaemic perfusion (2.5 mm K+ for 30 min) were assessed in isolated guinea-pig heart preparations using simultaneous recordings of volume-conducted electrocardiogram and monophasic action potentials from six ventricular epicardial sites. Effective refractory periods, ventricular fibrillation thresholds and inducibility of tachyarrhythmias by programmed electrical stimulation and tachypacing were determined at the LV and the RV epicardial stimulation sites. Hypokalaemia promoted spontaneous ventricular ectopic activity, an effect attributed to non-uniform prolongation of ventricular repolarization resulting in increased RV-to-LV transepicardial dispersion of refractoriness and action potential duration. Furthermore, hypokalaemic perfusion was associated with reduced ventricular fibrillation threshold and increased inducibility of tachyarrhythmias by programmed electrical stimulation and tachypacing as determined at the LV stimulation site. In contrast, the RV stimulation revealed no change in arrhythmic susceptibility of the RV chamber. Consistently, hypokalaemia reduced the LV effective refractory period but had no effect on the RV refractoriness. This change enabled generation of premature propagating responses by extrastimulus application at earlier time points during LV repolarization. Increased prematurity of extrastimulus-evoked propagating responses was associated with exaggerated local inhomogeneities in intraventricular conduction and action potential duration in hypokalaemic LV, thus creating a favourable stage for re-entrant tachyarrhythmias. Taken together, these findings suggest that proarrhythmic effects of hypokalaemia are mostly attributed to increased LV arrhythmogenicity in the guinea-pig heart. [source] Migraine Following Trans-Septal Access for Catheter Ablation of Cardiac ArrhythmiasHEADACHE, Issue 7 2009Palaniappan Saravanan MD There is increasing recognition that migraine with aura may be associated with intra-cardiac shunting because of a patent foramen ovale. Radio-frequency ablation to treat cardiac arrhythmias is an increasingly popular means of treating cardiac arrhythmias. Trans-septal puncture is routinely performed to gain access to the left atrium in order to ablate arrhythmias originating in the left heart. We report several cases of migraine triggered acutely by trans-septal puncture at our center. [source] Implantable cardioverter defibrillator in maintenance hemodialysis patients with ventricular tachyarrhythmias: A single-center experienceHEMODIALYSIS INTERNATIONAL, Issue 1 2009Itaru ITO Abstract Patients with hemodialysis (HD) are at risk of death due to cardiac arrhythmias, worsening congestive heart failure (CHF), and noncardiac causes. This study reviews our experience with the use of implantable cardioverter defibrillators (ICDs) in patients with ventricular tachycardia who are under maintenance HD. We retrospectively reviewed 71 consecutive patients who underwent an ICD implantation in our hospital. There were 11 patients under maintenance HD and 60 patients without HD. The group of patients with HD (HD group) was compared with the patients without HD (control group). The mean follow-up period was 30±9 vs. 39±4 months in the HD group vs. the control group, respectively. Among these patients, 6 in the HD group and 26 in the control group received appropriate ICD therapies. There was no difference in appropriate ICD therapy, time to the first therapy, and electrical storm between the 2 groups. In the HD group, 1 patient underwent surgical removal of the ICD system due to infective endocarditis. There were 5 deaths in the HD group (4 from CHF) and 8 deaths in the control group (4 from CHF). There were no sudden cardiac deaths or arrhythmic deaths in both groups of patients during the follow-up period. However, the overall death rate was significantly higher in the HD group (P<0.01). In HD patients, ICD therapy prevented arrhythmic death, but their rate of nonarrhythmic adverse outcomes was high. This risk-benefit association should be considered before implantation of the device. [source] Effect of acetate-free biofiltration with a potassium-profiled dialysate on the control of cardiac arrhythmias in patients at risk: A pilot studyHEMODIALYSIS INTERNATIONAL, Issue 1 2008Rosa I. MUÑOZ Abstract Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia. [source] Pharmacotherapy to Blunt Memories of Sexual Violence: What's a Feminist to Think?HYPATIA, Issue 3 2010ELISA A. HURLEY It has recently been discovered that propranolol,a beta-blocker traditionally used to treat cardiac arrhythmias and hypertension,might disrupt the formation of the emotionally disturbing memories that typically occur in the wake of traumatic events and consequently prevent the onset of trauma-induced psychological injuries such as Post-traumatic Stress Disorder. One context in which the use of propranolol is generating interest in both the popular and scientific press is sexual violence. Nevertheless, feminists have so far not weighed in on propranolol. I suggest that the time is ripe for a careful feminist analysis of the moral and political implications of propranolol use in the context of sexual violence. In this paper, I map the feminist issues potentially raised by providing propranolol to victims of sexual assault, focusing in particular on the compatibility of propranolol use and availability with an understanding of the social and systematic dimensions of rape's harms. I do not deliver a final verdict on propranolol; in fact, I show that we do not yet have enough information about propranolol's effects to do so. Rather, I provide a feminist framework for evaluating the possibilities and perils opened up by therapeutic memory manipulation in the context of sexual violence against women. [source] Cardiovascular mortality and morbidity in chronic obstructive pulmonary disease: the impact of bronchodilator treatmentINTERNAL MEDICINE JOURNAL, Issue 2 2010R. Wood-Baker Abstract Chronic obstructive pulmonary disease (COPD) is a substantial health burden. Cardiovascular disease (CVD), the leading cause of death, frequently coexists with COPD, an effect attributed to high individual disease prevalences and shared risk factors. It has long been recognized that COPD, whether stable or during acute exacerbations, is associated with an excess of cardiac arrhythmias. Bronchodilator medications have been implicated in the excess CVD seen in COPD, either as an intrinsic medication effect or related to side-effects. Despite the theory behind increased pro-arrhythmic effects in COPD, the reported results of trials investigating this for inhaled formulations at therapeutic doses are few. Methodological flaws, retrospective analysis and inadequate adjustment for concomitant medications, including short-acting ,relief' bronchodilators and non-respiratory medications with known arrhythmia propensity, mar many of these studies. For most bronchodilators at therapeutic levels in stable COPD, we can be reassured of their safety from current studies. The exception to this is ipratropium bromide, where the current data indicate an association with increased cardiovascular adverse effects. Moreover, there is no proven benefit from combining short-acting beta-agonists with short-acting anticholinergics at high doses in the acute setting, and although this practice is widespread, it is associated with increased cardiovascular risk. [source] Risk factors for falling in a psychogeriatric unitINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 8 2001A. John de Carle Abstract Objective To identify risk factors associated with falls in a psychogeriatric inpatient population. Design Retrospective cohort study. Setting A psychogeriatric inpatient unit in a Brown University affiliated psychiatric hospital. Participants A total of 1834 men and women who represented all admissions to the psychogeriatric inpatient unit between January 1992 and December 1995. Results Over the study period a total of 175 falls were recorded, giving a fall rate of 9.5%. Using a logistic regression model, six variables were found to be independently associated with an increased risk of falling: female gender, electroconvulsive therapy (ECT), mood stabilizers, cardiac arrhythmias, Parkinson's syndrome and dementias. Falls and ECT were associated with longer hospital stay, when adjusted for confounders including ECT. Conclusions These findings support previous results and identify ECT as a possible risk factor for falling in a hospital setting. Copyright © 2001 John Wiley & Sons, Ltd. [source] Reduction in the Sodium Currents in Isolated Ventricular Myocytes of Guinea Pigs Treated by Chronic L-Thyroxin MedicationJOURNAL OF CARDIAC SURGERY, Issue 6 2002Yu-Ping Ma Objective: Cardiac remodeling induced by chronic medication of L-thyroxin is manifested by a much more severe cardiac arrhythmias on the occlusion/reperfusion of the coronary artery in rats. A pattern of changes in ion currents in a diseased heart (L-thyroxin induced cardiac remodeling) is possibly provided as a basis of promoting malignant cardiac arrhythmias. An enhanced delayed outward rectifier potassium currents the rapid (IKr) and slow (IKS) component was found in the remodeled heart by L-thyroxin chronic medication. It is interested to investigate the changes in the sodium currents in the L-thyroxin remodeled guinea pig ventricle. Method: The remodeling model in guinea pig was developed by L-thyroxin 4 mg po for 10 days. On d 11, the heart was removed and perfused to isolate ventricular myocytes with medium of Ca2+ free medium containing collagen. The whole cell holding technique was applied. Results: The INa density in the L-thyroxin caused hypertrophied myocytes was reduced significantly at holding potential ,30 mV, ,53.20 +/,10.78pA/pF against ,73.78+/,14.66pA/pF in the normal. (n = 45, p < 0.001). No difference in the steady-state inactivation and recovery kinetics between the remodeled and the normal was found. The recovery constant 37.54+/,3.63 ms in the remodeled vs 36.57+/,2.81 ms in the normal (n = 18, p > 0.05). The accelerated deactivation time constant 3.67+/,0.14 of the remodeled (n = 39) against the normal 4.14+/,0.15 ms (n = 43) (p < 0.05). Conclusion: There is a reduced INa in the L-thyroxin remodeled ventricular myocytes and the deactivation of the current is accelerated. A changed depolarization of the affected myocardium is likely involved in the mechanism of arrhythmogenesis of the remodeled ventricle. [source] The Role of Cardiac Tissue Alignment in Modulating Electrical FunctionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2007CHIUNG-YIN CHUNG M.S. Introduction:,Most cardiac arrhythmias are associated with pathology-triggered ion channel remodeling. However, multicellular effects, for example, exaggerated anisotropy and altered cell-to-cell coupling, can also indirectly affect action potential morphology and electrical stability via changed electrotonus. These changes are particularly relevant in structural heart disease, including hypertrophy and infarction. Recent computational studies showed that electrotonus factors into stability by altering dynamic properties (restitution). We experimentally address the question of how cell alignment and connectivity alter tissue function and whether these effects depend on the direction of wave propagation. Methods and Results:,We show that cardiac cell arrangement can alter electrical stability in an in vitro cardiac tissue model by mechanisms both dependent and independent of the direction of wave propagation, and local structural remodeling can be felt beyond a space constant. Notably, restitution of action potential duration (APD) and conduction velocity was significantly steepened in the direction of cell alignment. Furthermore, prolongation of APD and calcium transient duration was found in highly anisotropic cell networks, both for longitudinal and transverse propagation. This is in contrast to expected correlation between wave propagation direction and APD based on electrotonic effects only, but is consistent with our findings of increased cell size and secretion of atrial natriuretic factor, a hypertrophy marker, in the aligned structures. Conclusion:,Our results show that anisotropic structure is a potent modulator of electrical stability via electrotonus and molecular signaling. Tissue alignment must be taken into account in experimental and computational models of arrhythmia generation and in designing effective treatment therapies. [source] A Common SCN5A Variant Alters the Responsiveness of Human Sodium Channels to Class I Antiarrhythmic AgentsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2007MOSSAAB SHURAIH M.D. Background: The potential pathophysiological role of common SCN5A polymorphisms in cardiac arrhythmias has been increasingly recognized. However, little is known about the impact of those polymorphisms on the pharmocological response of hNav1.5 to various antiarrhythmic agents. Methods and Results: The known SCN5A polymorphism, S524Y, was studied in comparison with the wild type (WT) define the SCN5A-Q1077del variant. The ion channel gating kinetics and pharmacology were evaluated using whole-cell patch-clamp methods in HEK-293 cells. Consistent with a previous report, the basal ion channel gating kinetics of S524Y were indistinguishable from the WT. Quinidine (20 ,M) caused similar extent of tonic block reduction of sodium currents at ,120 mV in WT and S524Y. Surprisingly, quinidine (20 ,M) exerted a more use-dependent block by a 10 Hz pulse train in S524Y than in WT at 22°C (Ki: WT, 51.3 ,M; S524Y, 20.3 ,M). S524Y significantly delayed recovery from the use-dependent block, compared with the WT (,= 88.6 ± 7.9 s vs 41.9 ± 6.6 s, P < 0.005). Under more physiological conditions using a 2 Hz pulse train at 37°C, S524Y similarly enhanced the use-dependent block by quinidine. In addition, S524Y enhanced the use-dependent block by flecainide (12.5 ,M), but not by mexiletine (100 ,M). Conclusion: A common SCN5A polymorphism, S524Y, can enhance a use-dependent block by class Ia and Ic antiarrhythmic agents. Our findings may have clinical implications in pharmacological management of cardiac arrhythmias since this common SCN5A polymorphism might be a contributing factor to the variable antiarrhythmic response. [source] Effects of Temporal Application Parameters on Lesion Dimensions During Transvenous Catheter CryoablationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2005HUNG-FAT TSE M.D. Background: Transvenous catheter cryoablation is a novel technique for treating cardiac arrhythmias. However, the relative importance of temporal application parameters on lesion dimension and clinical efficacy has not been studied. Methods and Results: We investigated the effects of (1) application duration: single 2.5 (2.5 × 1) versus single 5 versus double 2.5 (2.5 × 2) versus double 5 (5 × 2) minutes, (2) number of freeze,thaw cycles: single versus double, and (3) electrode contact area: horizontal versus vertical orientation, on the lesion diameter and depth during catheter cryoablation (10F, 6.5-mm tip-electrode, CryoCorÔ, San Diego) in a thigh muscle preparation. A total of 175 lesions (horizontal = 90, vertical = 85) were created in thigh muscle preparations on 10 swine. The lesion diameter and depth were significantly greater using 2.5 × 2 and 5 × 2 application modes as compared with 2.5 × 1 applications (P < 0.05). Horizontal tip-electrode orientation produced larger lesion diameter (P < 0.05), but not lesion depth as compared with vertical orientation. Multivariate analysis demonstrated that both tip-electrode orientation and duration of freeze >2.5 minutes were independent predictors for lesion diameter (P < 0.001). However, only duration of freeze >2.5 minutes was an independent predictor for lesion depth (P < 0.001). Conclusions: The dimensions of lesions created by catheter cryoablation are affected by mode of cryoablation application and electrode orientation. Increasing the duration of application, employing multiple freeze,thaw cycles at shorter cycle durations, and orienting the catheter to enhance/increase tissue contact can create a larger lesion. [source] Effects of Estrogen on Cardiac Electrophysiology in Female MiceJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2002SAMIR SABA M.D. Estrogen and Cardiac Electrophysiology.Introduction: Understanding the molecular mechanisms that underlie gender- and hormonal-related differences in susceptibility to cardiac arrhythmias has been hampered by the lack of a suitable animal model. We examined the effect of hormonal status on the electrophysiologic (EP) properties of the mouse heart in an in vivo, closed chest model. Methods and Results: Fifty-three female C57/J mice aged 10 to 12 weeks were studied. Thirty-six mice underwent bilateral ovariectomies; 18 received estrogen (OVX + E) and 18 received placebo (OVX). Seventeen female mice underwent only sham surgery. All animals underwent in vivo EP studies. Select EP parameters were measured after quinidine treatment. Data were analyzed by a blinded observer. Compared with the intact female mice, the PR and AH intervals were significantly shorter in the OVX mice, and these parameters normalized with estrogen replacement (PR = 45.9 ± 4.5 msec in the intact mice, 42.1 ± 4.3 msec in the OVX group, and 46.9 ± 3.5 msec in the OVX + E group, P < 0.005; AH = 36.5 ± 4.9 msec in the intact mice, 34.4 ± 4.7 msec in the OVX group, and 38.8 ± 2.7 msec in the OVX + E group, P = 0.03). The right ventricular effective refractory period was significantly shorter in the OVX mice versus the intact mice, and this also normalized with estrogen replacement. Hormonal status did not significantly affect any other EP variable, including QT interval. Conclusion: In female mice, estrogen prolongs AV nodal conduction and the right ventricular effective refractory period. Taken together, these data suggest that hormonal status affects aspects of cardiac EP function. Future application of this mouse model will be helpful in determining the molecular pathways that mediate hormonal differences in cardiac EP. [source] Modelling and imaging cardiac repolarization abnormalitiesJOURNAL OF INTERNAL MEDICINE, Issue 1 2006Y. RUDY Abstract. Repolarization abnormalities, including those induced by the congenital or acquired long QT (LQT) syndrome, provide a substrate for life-threatening cardiac arrhythmias. In this article, we use computational biology to link HERG mutations mechanistically to the resulting abnormalities of the whole-cell action potential. We study how the kinetic properties of IKs (the slow delayed rectifier) that are conferred by molecular subunit interactions, facilitate its role in repolarization and ,repolarization reserve'. A new noninvasive imaging modality (electrocardiographic imaging) is shown to image cardiac repolarization on the epicardial surface, suggesting its possible role in risk stratification, diagnosis and treatment of LQT syndrome. [source] Incidence of post-anaesthetic arrhythmias in dogsJOURNAL OF SMALL ANIMAL PRACTICE, Issue 3 2005K. Buhl Objectives: To assess the use of Holter monitoring for evaluating the incidence of post-anaesthetic cardiac arrhythmias and associated anaesthetic risk for two different anaesthetic protocols. Methods: Patients undergoing orthopaedic surgery were randomly divided into two groups with different anaesthetic regimens (group A, isoflurane n=30; group B, propofol n=30). Two 24-hour Holter recordings were performed for each patient: the first directly following anaesthesia and the second, as a comparison, on the fifth postoperative day. Results: Although all dogs were healthy on pre-anaesthetic cardiac evaluation, 56 dogs showed arrhythmias in the two 24-hour (Holter) electrocardiograms performed. However, the number of arrhythmias recorded was low in most cases (less than 10 supraventricular extrasystoles and less than 100 ventricular extrasystoles). One patient in group A showed 94 supraventricular extrasystoles during the second monitoring period. Three patients in each group developed more than 100 ventricular extrasystoles during both Holter recordings. There were no statistically significant differences between the two anaesthetic regimens or between the two recordings in both groups. Clinical Significance: The two anaesthetic protocols investigated in this study did not induce an increased incidence of severe arrhythmias in healthy dogs in the post-anaesthetic phase. [source] | |||||||||||||||||||||||||||||||||||||