			Home About us Contact

Interventricular Septum (interventricular + septum)

Distribution by Scientific Domains

Medical Sciences	68%
Life Sciences	27%

Selected Abstracts

Sinus of Valsalva Aneurysm with Dissection into the Interventricular Septum

ECHOCARDIOGRAPHY, Issue 1 2008
Maria do Carmo P. Nunes M.D., Ph.D.
No abstract is available for this article. [source]

Normal Development of the Muscular Region of the Interventricular Septum.

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2009

Summary In a first paper, we concluded that the muscular region of the interventricular septum is developed by the trabecular branches and showed evidence that the developing interventricular septum elongates in a direction opposite to that of atria. Nevertheless, to date the literature is lacking precise information on the importance of myocardial proliferation not only in this process but also in the morphogenesis of the ventricular cavities. The aim of this study was to determine the spatial and temporal distribution of high-intensity foci of cycling myocytes in the ventricular region of the heart of chicken embryos during cardiac septation. Histological studies, detection of the proliferating cell nuclear antigen by light and confocal microscopy and flow cytometric analysis were carried out. The results corroborate that the developing interventricular septum grows in a direction opposite to that of atria. A remoulding mechanism that results in fenestrated trabecular sheets and trabecular branching is discussed. Our findings allowed us to summarize the normal morphogenesis of the muscular region of the interventricular septum in a way that is different from that suggested by other researchers. [source]

Activation of Tolloid-like 1 gene expression by the cardiac specific homeobox gene Nkx2,5

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 4 2009
Inna Sabirzhanova
Mammalian Tolloid-like 1 (Tll-1) is a pleiotropic metalloprotease that is expressed by a small subset of cells within the precardiac mesoderm and is necessary for proper heart development. Following heart tube formation Tll-1 is expressed by the endocardium and regions of myocardium overlying the region of the muscular interventricular septum. Mutations in Tll-1 lead to embryonic lethality due to cardiac defects. We demonstrate that the Tll-1 promoter contains Nkx2,5 binding sites and that the Tll-1 promoter is activated by and directly binds Nkx2,5. Tll-1 expression is ablated by a dominant negative Nkx2,5 or by mutation of the Nkx2,5 binding sites within the Tll-1 promoter. In vivo, Tll-1 expression is decreased in the hearts of Nkx2,5 knockout embryos when compared with hemizygous and wild-type embryos. These results show that Nkx2,5 is a direct activator of Tll-1 expression and provide insight into the mechanism of the defects found in both the Tll-1 and Nkx2,5 knockout mice. [source]

Differential levels of tissue hypoxia in the developing chicken heart

DEVELOPMENTAL DYNAMICS, Issue 1 2006
Jamie Wikenheiser
Abstract Tissue hypoxia plays a critical role in normal development, including cardiogenesis. Previously, we showed that oxygen concentration, as assessed by the hypoxia indicator EF5, is lowest in the outflow tract (OFT) myocardium of the developing chicken heart and may be regulating events in OFT morphogenesis. In this study, we identified additional areas of the embryonic chicken heart that were intensely positive for EF5 within the myocardium in discrete regions of the atrial wall and the interventricular septum (IVS). The region of the IVS that is EF5-positive includes a portion of the developing central conduction system identified by HNK-1 co-immunostaining. The EF5 positive tissues were also specifically positive for nuclear-localized hypoxia inducible factor 1, (HIF-1,), the oxygen-sensitive component of the hypoxia inducible factor 1 (HIF-1) heterodimer. The pattern of the most intensely EF5-stained myocardial regions of the atria and IVS resemble the pattern of the major coronary vessels that form in later stages within or immediately adjacent to these particular regions. These vessels include the sinoatrial nodal artery that is a branch of the right coronary artery within the atrial wall and the anterior/posterior interventricular vessels of the IVS. These findings indicate that a portion of the developing central conduction system and the patterning of coronary vessels may be subject to a level of regulation that is dependent on differential oxygen concentration within cardiac tissues and subsequent HIF-1 regulation of gene expression. Developmental Dynamics 235:115,123, 2006. © 2005 Wiley-Liss, Inc. [source]

Left Ventricular Function in Male Patients with Secondary Hypogonadism

ECHOCARDIOGRAPHY, Issue 3 2007
Oben Baysan M.D.
Background: In addition to the effects on ventricular repolarization, testosterone could also affect left ventricular performance. The enhancement of left ventricular contractility in testosterone-deficient rats following testosterone replacement implies to the possible testosterone effect. Objectives: The aim of the current study is to reveal the alterations of left ventricular functions, if any, in secondary hypogonadal male patients. Methods: Thirty-four males with secondary hypogonadism comprised the study group. The control group consisted of 30 healthy subjects. Echocardiographic measurements including left ventricular dimensions, ejection fraction, mitral inflow, and left ventricular outflow parameters were obtained from all subjects. Tissue Doppler parameters were also measured from left ventricular lateral wall and interventricular septum. Results: Left ventricular diameters, wall thicknesses, and performance parameters were similar in both groups. Mitral inflow parameters showed a statistically insignificant difference. Pulse-wave tissue Doppler interpretation of hypogonadal and healthy subjects were similar in terms of lateral and septal basal segment Sm, Em, and Am wave velocities. Conclusions: Regarding the findings of previous studies that showed impaired myocardial contractility and lusitropy in testosterone deficient rats and our study results, further studies are needed for better understanding of testosterone's effects on human myocardium. [source]

Progress of Untreated Massive Cardiac Echinococcosis,Echocardiographic Follow-Up

ECHOCARDIOGRAPHY, Issue 9 2006
Serdar Soydinc M.D.
A 56-year-old man was admitted with chest pain and dyspnea. Echocardiographic evaluation revealed a giant cystic cardiac mass with multiple loculations at interventricular septum extended to inferoposterior region protruding inside the cavity. The patient refused surgical therapy. His complaints persisted without significant changes after 5 months. Second echocardiographic evaluation revealed conjugation of previous multiple cyst to gigantic intramyocardial cyst and minimal pericardial effusion. We intend to illustrate herein an unusual echocardiographic appearance and progress of an untreated massive "cardiac echinococcosis." If cardiac hydatid cyst is left untreated it may transform to large cavity with a high risk of rupture. [source]

Echocardiographic Follow-Up of Patients with Takayasu's Arteritis: Five-Year Survival

ECHOCARDIOGRAPHY, Issue 5 2006
María Elena Soto M.D, Ms.Sc.
Takayasu's arteritis (TA) is a primary vasculitis that causes stenosis or occlusion, rarely aneurysm and distal ischemia. This study was undertaken to examine cardiovascular damage using echocardiography and determine the causes of morbid-mortality in Mexican Mestizo patients with TA. Seventy-six patients were studied by transthoracic echocardiography. Left ventricular diameters, parietal thickness, systolic function, and wall motion were analyzed, also, valvular lesions and aorta features were assessed. Thickness of the interventricular septum was 12 mm ± 3 (8,19), and that of posterior wall was 12 mm ± 2 (9,18). The average left ventricular diastolic diameter was 47 mm ± 7 (33,68) and the left ventricular systolic diameter 32 mm ± 8 (16,64). The left ventricular ejection fraction was of 57 ± 11%. Left ventricular concentric hypertrophy was found in 28 (50%) of the 56 hypertensive patients. The five-year survival of patients with left ventricular concentric hypertrophy was 80%, compared to 95% in patients without hypertrophy (P = 0.00). Abnormal wall motion was found in 15 patients. Thirty-one patients had aortic regurgitation, 19 had mitral regurgitation, 13 had tricuspid regurgitation, and 10 and pulmonary hypertension. Six patients had aneurysms of ascending aorta and 7 stenosis of descending aorta. Thirteen of 76 patients died (17%), 85% were hypertensive, and 9% also had acute myocardial infarction (AMI). Echocardiography, a noninvasive technique, shows a great utility in detection and follow-up of cardiovascular manifestations in patients with TA. New techniques, more sensitive toward detecting the early stages of left ventricular dysfunction, are promising to limit left ventricular hypertrophy development. [source]

Age Dependency of Myocardial Structure: A Quantitative Two-Dimensional Echocardiography Study in a Normal Population

ECHOCARDIOGRAPHY, Issue 3 2000
MARIA-AURORA MORALES M.D.
Histological changes of the myocardium occur with aging due to an increase in collagen content, hypertrophy of fibers, and patchy fibrosis. Quantitative analysis of conventional echocardiographic images provides an in vivo assessment of myocardial structure by the evaluation of the gray level distribution; with this technique, a relation between myocardial fibrosis and pathological ultrasonic response has been documented. The aim of this study was to evaluate the relation between ultrason-ically assessed myocardial structure and age in a normal population. Seventy-eight subjects (47 men; mean age, 51 years; age range, 23,87 years) without apparent cardiovascular and systemic disease underwent conventional two-dimensional echocardiographic examinations. Still frames at end-diastole from apical four-chamber view were digitized and converted in matrices of 256 × 256 pixels. First-order statistical analysis was performed to describe a region of interest in the interventricular septum. The following parameters were studied: mean (gray level amplitude), standard deviation (overall contrast), uniformity (tonal organization), and entropy (tendency of gray levels to be spread). Myocardial structure was assessed in 75 of 78 subjects, divided into three groups: I, age 23,40 years; II, age 41,65 years; and III, > 65 years. Significant differences for all the parameters were found between the age groups. Age correlated directly with mean and entropy (r = 0.77 and 0.69, respectively) and inversely with uniformity (r = 0.70). Our results suggest that quantitative echocardiography can reveal age-related changes in myocardial structure that are characterized by a greater echogenicity and loss in tonal organization, possibly due to increased collagen content within the fibers. [source]

Relationship Between Regional Shortening and Asynchronous Electrical Activation in a Three-Dimensional Model of Ventricular Electromechanics

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2003
TARAS P. USYK Ph.D.
Introduction: Asynchronous electrical activation can cause abnormalities in perfusion and pump function. An electromechanical model was used to investigate the mechanical effects of altered cardiac activation sequence. Methods and Results: We used an anatomically detailed three-dimensional computational model of the canine ventricular walls to investigate the relationship between regional electrical activation and the timing of fiber shortening during normal and ventricular paced beats. By including a simplified Purkinje fiber network and anisotropic impulse conduction in the model, computed electrical activation sequences were consistent with experimentally observed patterns. Asynchronous time courses of regional strains during beats stimulated from the left or right ventricular epicardium showed good agreement with published experimental measurements in dogs using magnetic resonance imaging tagging methods. When electrical depolarization in the model was coupled to the onset of local contractile tension development by a constant time delay of 8 msec, the mean delay from depolarization to the onset of systolic fiber shortening was 14 msec. However, the delay between the onset of fiber tension and initial shortening varied significantly; it was as late as 60 msec in some regions but was also as early as ,50 msec (i.e., 42 msec before depolarization) in other regions, particularly the interventricular septum during free-wall pacing. Conclusion: The large variation in delay times was attributable to several factors including local anatomic variations, the location of the site relative to the activation wavefront, and regional end-diastolic strain. Therefore, we conclude that these factors, which are intrinsic to three-dimensional ventricular function, make the regional sequence of fiber shortening an unreliable surrogate for regional depolarization or electromechanical activation in the intact ventricles. (J Cardiovasc Electrophysiol, Vol. 14, pp. S196-S202, October 2003, Suppl.) [source]

Noninvasive Assessment of Cardiac Resynchronization Therapy for Congestive Heart Failure Using Myocardial Strain and Left Ventricular Peak Power as Parameters of Myocardial Synchrony and Function

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2002
Ph.D., ZORAN B. POPOVI
Resynchronization Therapy for Heart Failure.Introduction: Although invasive studies have shown that cardiac resynchronization therapy by biventricular pacing improves left ventricular (LV) function in selected heart failure patients, it is impractical to apply such techniques in the clinical setting. The aim of this study was to assess the acute effects of cardiac resynchronization therapy by noninvasive techniques. Methods and Results: Twenty-two patients enrolled in the InSync trial (age 64 ± 9 years, 18 men and 4 women; all with ejection fraction <35% and QRS >130 msec) were studied 1 to 12 months after pacemaker implantation during pacing, and while ventricular pacing was inhibited. Regional myocardial strains of the interventricular septum, LV free wall, and right ventricular free wall were derived from color Doppler tissue echocardiography. Peak power index was calculated as a product of simultaneously recorded noninvasive blood pressure and pulse-wave (PW) Doppler velocity of the LV outflow tract. The Z ratio (sum of LV ejection and filling times divided by RR interval) and tei index were calculated from PW Doppler data. During pacing, overall regional strain improved (P = 0.01), while the LV strain coefficient of variation decreased from 2.7 ± 2.4 to 1.3 ± 0.7 (P = 0.009). Additionally, peak power index improved from 84 ± 24 to 94 ± 27 cm· mmHg/sec (P = 0.004). The Z ratio increased from 0.71 ± 0.08 to 0.78 ± 0.07 (P = 0.0005), while the tei index decreased from 0.86 ± 0.33 to 0.59 ± 0.16 (P = 0.0002). Conclusion: Using novel noninvasive indices, we demonstrated that cardiac resynchronization therapy improves LV performance. [source]

Role of Structural Complexities of Septal Tissue in Maintaining Ventricular Fibrillation in Isolated, Perfused Canine Ventricle

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2001
TAKANORI IKEDA M.D.
Tissue Structure and VF.Introduction: It is unclear how the patterns of wavelet propagation during ventricular fibrillation (VF) vary between structurally different tissues. We hypothesized that the structural complexities of septal tissue influence the maintenance of reentrant wavelets in the ventricle. Methods and Results: Endocardial activation patterns during VF were analyzed in the isolated, perfused canine right ventricular (RV) free wall (n = 9), interventricular septum (n = 5), and left ventricular (LV) free wall (n = 6) using a computerized mapping system (2-mm resolution) with 120-msec consecutive windows. Each tissue sample was cut progressively to reduce the tissue mass until the VF was terminated. More wavelets were seen in the septa than in the RV and LV free walls at baseline (P = 0.004), and VF in the septa displayed a shorter cycle length than in the RV and LV free walls (P = 0.017). As the tissue mass decreased, VF became successively more organized in all regions: the number of wavelets decreased and the cycle length of VF lengthened. Single and "figure-of-eight" stationary, reentrant wavelets often were mapped after tissue mass reduction in the RV free walls and rarely in the LV free walls, but they were not observed in the septa. Less critical mass was required to maintain VF in the septa than in the RV and LV free walls (P = 0.0006). Gross anatomic and histologic examinations indicated that the tissue structure of the septa is more complex than that of the RV and LV free walls. Conclusion: VF activation patterns with progressive reduction of tissue mass differ for the septum and the ventricular free walls. The structural complexities of the septal tissue influence the maintenance of fibrillation in the ventricle. [source]

Acoustic videodensitometric parameters correlate with abnormalities of left ventricular filling in hypertensive patients assessed via doppler tissue imaging

JOURNAL OF CLINICAL ULTRASOUND, Issue 8 2007
Paul Coulon
Abstract Purpose Using a videodensitometric technique developed in our center we investigated whether the amplitude of variation of gray levels in the interventricular septum was related to functional parameters, especially ventricular filling as studied by doppler tissue imaging (DTI) in hypertensive patients. Methods and Results We included 35 hypertensive patients from whom we recorded a two dimensional sequence of the left ventricle from the short axis parasternal view and a doppler tissue scan of the mitral ring. Two-dimensional sections were then analyzed with Iodp software to measure variations in levels of gray in the septum. We observed significant correlations between these variations and the velocity of the Ea wave on DTI of the lateral wall (r = 0.49, p < 0.002). On dividing this population into three sub-groups according to the Appleton classification of ventricular filling, we noted a tendency to a reduction in amplitude of variations of gray of the septum in cases with abnormalities of relaxation. This was even more marked in cases with a restrictive or pseudo-normal profile. Conclusion These observations point to the interest of sonographic videodensitometry in the evaluation of hypertensive cardiopathy. Further studies will be required to determine whether it can define the extent of the abnormalities of myocardial structure and the degree of fibrosis. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007 [source]

Sudden Death from Tubercular Myocarditis

JOURNAL OF FORENSIC SCIENCES, Issue 3 2006
Enrico Silingardi M.D.
ABSTRACT: Tuberculous myocarditis is a rare finding. We present the case of a 33-year-old woman who was in good health and who died suddenly at home. Autopsy and histopathologic examinations revealed granulamatous lesions in the myocardium, lungs, lymph nodes, liver, and spleen. No fast acid bacilli were demonstrated on histological examination. The presence of a Mycobacterium tuberculosis DNA complex was identified using a polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded histological samples. An HIV test carried out on the blood obtained during the autopsy was negative according to the DNA amplification technique (PCR) and enzyme-linked immunosorbent assay serological test. We hypothesize that the mechanism of death was severe ventricular arrhythmia due to granulomatous proliferation in the structures of the interventricular septum. [source]

Good neurological recovery after cardiopulmonary resuscitation and thrombolysis in two old patients with pulmonary embolism

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2009
F. CAVALLARO
The use of thrombolysis as an emergency treatment for cardiac arrest (CA) due to massive pulmonary embolism (MPE) has been described. However, there are no reports of successful treatment of MPE-associated CA in patients over 77 years of age. We report two cases of successful cardiopulmonary resuscitation for an MPE-associated CA in two very old women (87 and 86 years of age). In both cases, typical signs of MPE were documented using emergency echocardiography, which showed an acute right ventricle enlargement and a paradoxical movement of the interventricular septum. Emergency thrombolysis was administered during resuscitation, which lasted 45 and 21 min, respectively. Despite old age and prolonged resuscitation efforts, both patients had good neurological recovery and one of them was alive and neurologically intact 1 year later. Thrombolysis is a potentially useful therapy in MPE-associated CA. A good neurological outcome can be obtained even in very old patients and after prolonged resuscitation. [source]

Cardiac involvement in infantile Sandhoff disease

JOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 1 2002
P Venugopalan
Abstract: An 18-month-old boy with enzyme assay-confirmed infantile Sandhoff disease (MIM 268800) is reported. Besides the classical neurological features, this patient exhibited severe mitral regurgitation secondary to mitral valve prolapse and mild aortic regurgitation from aortic valve prolapse. He also had asymmetric hypertrophy of the interventricular septum without left ventricular outflow tract obstruction. [source]

Tissue Doppler and Strain Imaging in Dogs with Myxomatous Mitral Valve Disease in Different Stages of Congestive Heart Failure

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 6 2009
A. Tidholm
Background: Tissue Doppler imaging (TDI) including strain and strain rate (SR) assess systolic and diastolic myocardial function. Hypothesis: TDI, strain, and SR variables of the left ventricle (LV) and the interventricular septum (IVS) differ significantly between dogs with myxomatous mitral valve disease (MMVD) with and without congestive heart failure (CHF). Animals: Sixty-one dogs with MMVD with and without CHF. Ten healthy control dogs. Methods: Prospective observational study. Results: Radial motion: None of the systolic variables were altered and 3 of the diastolic velocities were significantly increased in dogs with CHF compared with dogs without CHF and control dogs. Longitudinal motion: 2 systolic velocities and 3 diastolic velocities were significantly increased in dogs with CHF compared with dogs without CHF and control dogs. Difference in systolic velocity time-to-peak between LV and IVS was significantly increased in dogs with MMVD with and without CHF compared with control dogs. In total, 11 (23%) of 48 TDI and strain variables differed significantly between groups. Left atrial to aortic ratio was positively correlated to early diastolic velocities, percentage increase in left ventricular internal diameter in systole was positively correlated to systolic and diastolic velocities, and mitral E wave to peak early diastolic velocity in the LV basal segment (E/Em) was positively correlated to radial strain and SR. Conclusions and Clinical Importance: Few TDI and strain variables were changed in dogs with MMVD with and without CHF. Intraventricular dyssynchrony may be an early sign of MMVD or may be an age-related finding. [source]

Spontaneous Feline Hypertension: Clinical and Echocardiographic Abnormalities, and Survival Rate

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2003
Valerie Chetboul
Systemic hypertension was diagnosed in 58 of 188 untreated cats referred for evaluation of suspected hypertension-associated ocular, neurologic, cardiorespiratory, and urinary disease, or diseases frequently associated with hypertension (hyperthyroidism and chronic renal failure). Hypertensive cats were significantly older than normotensive subjects (13.0 ± 3.5 years versus 9.6 ± 5.0 years; P < .01), and had a greater prevalence of retinal lesions (48 versus 3%; P < .001), gallop rhythm (16 versus 0%; P < .001), and polyuria-polydipsia (53 versus 29%; P < .01). Blood pressure was significantly higher (P < .001) in cats with retinopathies (262 ± 34 mm Hg) than in other hypertensive animals (221 ± 34 mm Hg). Hypertensive cats had a thicker interventricular septum (5.8 ± 1.7 versus 3.7 ± 0.64 mm; P < .001) and left ventricular free wall (6.2 ± 1.6 versus 4.1 ± 0.51 mm; P < .001) and a reduced diastolic left ventricular internal diameter (13.5 ± 3.2 versus 15.8 ± 0.72 mm; P < .001) than control cats. Left ventricular geometry was abnormal in 33 of 39 hypertensive subjects. No significant difference was found in age or blood pressure at the initial visit between cats that died or survived over a 9-month period after initial diagnosis of hypertension. Mean survival times were not significantly different between hypertensive cats with normal and abnormal left ventricular patterns. Further prospective studies are needed to clearly identify the factors involved in survival time in hypertensive cats. [source]

Cardiac Troponin I in Feline Hypertrophic Cardiomyopathy

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2002
William E. Hemdon
Measurement of plasma cardiac troponin I concentration ([cTnI]) is a sensitive and specific means for detecting myocardial damage in many mammalian species. Studies have shown that [cTnI] increases rapidly after cardiomyocyte injury. The molecular structure of cTnl is highly conserved across species, and current assays developed for its detection in humans have been validated in many species. In this study, [cTnI] was quantified using a 2-site sandwich assay in plasma of healthy control cats (n = 33) and cats with moderate to severe hypertrophic cardiomyopathy (HCM) (n = 20). [cTnI] was significantly higher in cats with HCM (median, 0.66 ng/mL; range, 0.05,10.93 ng/mL) as compared with normal cats (median, <0.03 ng/mL; range, <0.03-0.16 ng/mL) (P < .0001). An increase in [cTnI] was also highly sensitive (sensitivity = 85%) and specific (specificity = 97%) for differentiating cats with moderate to severe HCM from normal cats. [cTnI] was weakly correlated with diastolic thickness of the left ventricular free wall (r2= .354; P= .009) but not with the diastolic thickness of the interventricular septum (P= .8467) or the left atrium: aorta ratio (P= .0652). Furthermore, cats with congestive heart failure at the time of cTnl analysis had a significantly higher [cTnI] than did cats that had never had heart failure and those whose heart failure was controlled at the time of analysis (P= .0095 and P= .0201, respectively). These data indicate that cats with HCM have ongoing myocardial damage. Although the origin of this damage is unknown, it most likely explains the replacement fibrosis that is consistently identified in cats with moderate to severe HCM. [source]

Excitation of the Intrinsic Conduction System Through His and Interventricular Septal Pacing

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2006
TIMOTHY G LASKE
Background: Direct His bundle pacing results in rapid synchronous ventricular activation. However, clinical experiences with such pacing have been associated with long procedure times and compromised pacing and sensing performance. Methods: We evaluated myocardial activation sequences (AS) for pacing of the His bundle and peri-His region and assessed acute pacing performance using custom-designed plunge electrodes. Unipolar pacing was performed in isolated swine hearts (n = 10) using four quadripolar stimulation/sensing electrodes implanted into the interventricular septum and equally spaced between the membranous septum and the coronary sinus ostium (zones 1,4, respectively; electrode depth (ED) 1 = most distal, ED 4 = most proximal). Optimal pacing sites were defined as: pacing thresholds ,1.5 V, a P-R ratio of ,0.5, and ,50% occurrence of an intrinsic midseptal left ventricular (LV) endocardial electrical breakout (BO) and activation pattern. Results: Pacing thresholds improved with greater depth of electrode location within the septum (ED 1: 1.51 ± 0.8 V vs ED 4: 5.2 ± 3.8 V, P < 0.001), as did the P-R ratio (0.34 ± 0.6 vs 0.78 ± 1.0, P < 0.05). His potentials were only observed in zone 1 and 2 electrodes (0.12 and 0.02 mV, respectively). Only electrodes in zones 1 and 2 produced LV endocardial electrical BOs in the midseptal region that demonstrated an intrinsic-like endocardial AS. Depth 1 and 2 electrodes (11.75 and 8.75 mm, respectively) in zone 1 satisfied all three optimal pacing site requirements. Conclusions: This study has shown that LV activation patterns similar to sinus rhythm may be achieved without direct activation of the His bundle, while maintaining acceptable pacing and sensing performance. These data indicate that pacing systems designed to stimulate the tissues below the point at which the His bundle penetrates the central fibrous body may provide improved system efficiency and LV performance in comparison to both direct His bundle pacing and traditional pacing sites. [source]

Initial Experience with an Active-Fixation Defibrillation Electrode and the Presence of Nonphysiological Sensing

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2001
RAHUL N. DOSHI
DOSHI, R.N., et al.: Initial Experience with an Active-Fixation Defibrillation Electrode and the Presence of Nonphysiological Sensing. Nonphysiological sensing by a pacing and defibrillation electrode may result in inappropriate defibrillator discharges and/or inhibition of pacing. Active-fixation electrodes may be more likely to sense diaphragmatic myopotentials because of the protrusion of the screw for fixation. In addition, the movement of the fixation screw in an integrated bipolar lead system could also result in inappropriate sensing. This may be increasingly important in patients who are pacemaker dependent because the dynamic range of the autogain feature of these devices is much more narrow. Five of 15 consecutive patients who received a CPI model 0154 or 0155 active-fixation defibrillation electrode with an ICD system (CPI Ventak AV3DR model 1831 or CPI Ventak VR model 1774 defibrillator) are described. In 2 of the 15 patients, nonphysiological sensing appearing to be diaphragmatic myopotentials resulted in inappropriate defibrillator discharges. Both patients were pacemaker dependent. Changes in the sensitivity from nominal to less sensitive prevented inappropriate discharges. In one patient, discreet nonphysiological sensed events with the electrogram suggestive of ventricular activation was noted at the time of implantation. This was completely eliminated by redeployment of the active-fixation lead in the interventricular septum. In two other patients, discreet nonphysiological sensed events resulted in intermittent inhibition of ventricular pacing after implantation. These were still seen in the least sensitive autogain mode for ventricular amplitude. These were not seen on subsequent interrogation 1 month after implantation. Increased awareness of nonphysiological sensing is recommended. The CPI 0154 and 0155 leads seem to be particularly prone to this abnormality. Particular attention should be made when deploying an active-fixation screw for an integrated bipolar lead. This increased awareness is more important when a given individual is pacemaker dependent, which may warrant DFT testing in a least or less sensitive mode in these patients. [source]

Regional Differences in Arrhythmogenic Aftereffects of High Intensity DC Stimulation in the Ventricles

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2000
ITSUO KODAMA
Regional differences of the aftereffects of high intensity DC stimulation were investigated in isolated rabbit hearts stained with a voltage-sensitive dye (di-4-ANEPPS). Optical action potential signals were recorded from the epicardial surface of the right and left ventricular free wall (RVep, LVep) and from the right endocardial surface of the interventricular septum (IVS). Ten-millisecond monophasic DC stimulation (S2, 20,120 V) was applied to the signal recording spots during the early plateau phase of the action potential induced by basic stimuli (S1, 2.5 Hz). There was a linear relationship between S2 voltage and the S2 field intentisy (FI). S2 caused postshock additional depolarization. giving rise to a prolongation of the shocked action potential. With S2, 40 V (FI ,,20 V/cm), terminal repolarization of action potential was inhibited, and subsequent postshock S1 action potentials for 1,5 minutes were characterized by a decrease in the maximum diastolic potential and a decrease in the amplitude and a slowing of their upstroke phase. The higher the S2 voltage, the larger the aftereffects. The changes in postshock action potential configuration in RVep were significantly greater than those observed in LVep and IVS when compared at the same levels of S2 intensity. In RVep, 12 of 20 shocks of 120 V resulted in a prolonged refractoriness to S1 (> 1 s), and the arrest was often followed by oscillation of membrane potential. Ventricular tachycardia or fibrillation ensued from the oscillation in five cases. No such long arrest or serious arrhythmias were elicited in LVep and IVS. These results suggest that RVep is more susceptible than LVep and IVS for arrhythmogenic aftereffects of high intensity DC stimulation. [source]

Miliary Neonatal Hemangiomatosis with Fulminant Heart Failure and Cardiac Septal Hypertrophy in Two Infants

PEDIATRIC DERMATOLOGY, Issue 4 2004
A. H. O'Hagan M.B., M.R.C.P.
We report two infants with this condition who had fulminant cardiac failure and cardiac septal hypertrophy. The first was a 5-day-old boy who presented with increasing numbers of cutaneous hemangiomata associated with worsening cardiac failure. Magnetic resonance imaging (MRI) showed extensive hepatic hemangioma. Despite treatment with systemic corticosteroids and subcutaneous interferon alfa-2b his disease progressed. Hepatic artery embolization was unsuccessful. The infant died of congestive cardiac failure at 6 weeks of age. Postmortem examination showed a massively enlarged cardiac interventricular septum and biventricular hypertrophy. The second patient was a 1-week-old girl who also had cutaneous hemangioma and cardiac decompensation. MRI showed extensive intrahepatic involvement. She was treated early with corticosteroids and interferon ,, which resulted in involution of the cutaneous and hepatic lesions. Cardiac septal hypertrophy did not persist at late follow-up, and the association of miliary neonatal hemangiomatosis and cardiac septal hypertrophy has not yet been established. [source]

Domino Heart Transplantation Involving Infants

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2007
T. L. Astor
Domino heart transplantation has been well described in adults, but has not previously been reported in infant patients. We report the successful transplantation of a ,domino' heart from a 3-month-old infant with primary pulmonary hypertension undergoing heart,lung transplantation, into a 3-month-old infant with complex congenital heart disease. Both infants have survived past 1 year post-transplant, and neither infant has experienced any clinically significant allograft-related complications. Echocardiography and cardiac catheterization of the domino heart have consistently demonstrated stable hypertrophy of the right ventricle (RV) and interventricular septum, but good right and left ventricular function. Domino heart transplant surgery may be an effective way to provide ,pre-conditioned' donor hearts to infants urgently in need of heart transplantation. [source]

Normal Development of the Muscular Region of the Interventricular Septum.

The Distribution of the Cardiac Veins in Angora Rabbits (Oryctolagus cuniculus)

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2007
S. Bahar
Summary This study was carried out to describe the ramifications of the cardiac veins of Angora rabbit. For this purpose, a total of 16 adult healthy Angora rabbits of both sexes, 1.5,2 years of age, were used. The great, middle, right cardiac veins ran in a subepicardial course and opened into the left cranial vena cava, but some tributaries of the right cardiac veins sometimes also joined various portions of the right atrium. The smallest cardiac veins followed subendocardially and terminated in the right chambers of the heart. Based on their origin, course and frequency, it was concluded that the smallest cardiac veins are primarily responsible for the drainage of the interventricular septum. Results from this study are thought to shed light on further heart-related medical studies, and to contribute considerably to the present anatomical knowledge of the cardiac veins in this species. [source]

The Effect of Vascular Endothelial Growth Factor on in vitro Embryonic Heart Development in Rats

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2004
H. Ülger
Summary In vitro effects of vascular endothelial growth factor (VEGF) on heart development and total embryonic growth were investigated in 84 rat embryos (obtained from nine pregnant females) at 9.5 days of gestation that were cultured in whole rat serum (WRS), in <30 kDa + >50 kDa serum fractions [retenate (R)], and in R + VEGF. After 24-h culture, the embryos from each group were harvested and divided into two groups. One group was analysed morphologically and biochemically to obtain embryo protein content, the second group was serially sectioned and examined by light microscopy. Morphological score, embryo protein content, somite number and crown-rump length of embryos indicated that embryos cultured in R had significant embryonic retardation, whereas the addition of VEGF to R increased embryonic growth and development. The morphological scores for WRS, R and R + VEGF were 57.7 ± 0.87, 46.6 ± 1.90 and 52.1 ± 0.97, somite numbers were 26.5 ± 0.47, 20.1 ± 0.63 and 24.4 ± 0.46, crown-rump lengths were 3 ± 0.07, 2.4 ± 0.06 and 2.7 ± 0.06 mm, and embryo protein contents were 160.5 ± 7.41, 98.2 ± 4.81 and 141.1 ± 10.96 ,g per embryo, respectively. The results of histological examination of heart development were similar. The hearts of embryos grown in R were unseptated and tubular. The atrioventricular endocardial cushions were incompletely developed. The addition of VEGF to R improved heart development. There were no gross morphological differences in the cardiac development between embryos grown in WRS and R + VEGF. In both groups, development of the muscular interventricular septum had begun. Development of the atrioventricular cushions was also similar in both groups and had caused narrowing of the atrioventricular canals, but the atrial septation was not observed. [source]

Developmental consequences of abnormal folate transport during murine heart morphogenesis ,

BIRTH DEFECTS RESEARCH, Issue 7 2004
Louisa S. Tang
Abstract BACKGROUND Folic acid is essential for the synthesis of nucleotides and methyl transfer reactions. Folic acid,binding protein one (Folbp1) is the primary mediator of folic acid transport into murine cells. Folbp1 knockout mouse embryos die in utero with multiple malformations, including severe congenital heart defects (CHDs). Although maternal folate supplementation is believed to prevent human conotruncal heart defects, its precise role during cardiac morphogenesis remains unclear. In this study, we examined the role of folic acid on the phenotypic expression of heart defects in Folbp1 mice, mindful of the importance of neural crest cells to the formation of the conotruncus. METHODS To determine if the Folbp1 gene participates in the commitment and differentiation of the cardiomyocytes, relative levels of dead and proliferating precursor cells in the heart were examined by flow cytometry, Western blot, and immunohistostaining. RESULTS Our studies revealed that impaired folic acid transport results in extensive apoptosis-mediated cell death, which concentrated in the interventricular septum and truncus arteriosus, thus being anatomically restricted to the two regions of congenital heart defects. Together with a reduced proliferative capacity of the cardiomyocytes, the limited size of the available precursor cell pool may contribute to the observed cardiac defects. Notably, there is a substantial reduction in Pax-3 expression in the region of the presumptive migrating cardiac neural crest, suggesting that this cell population may be the most severely affected by the massive cell death. CONCLUSIONS Our findings demonstrate for the first time a prominent role of the Folbp1 gene in mediating susceptibility to heart defects. Birth Defects Research (Part A), 2004. © 2004 Wiley-Liss, Inc. [source]

Postsystolic thickening detected by doppler myocardial imaging: A marker of viability or ischemia in patients with myocardial infarction

CLINICAL CARDIOLOGY, Issue 1 2004
Jae-Kwan Song M.D.
Abstract Background: Postsystolic thickening (PST) of ischemic myocardial segments has been reported to account for the characteristic heterogeneity or regional asynchrony of myocardial wall motion during acute ischemia. Hypothesis: Postsystolic thickening detected by Doppler myocardial imaging (DMI) could be a useful clinical index of myocardial viability or peri-infarction viability in patients with myocardial infarction (MI). Methods: Doppler myocardial imaging was recorded at each stage of a standard dobutamine stress echocardiogram (DSE) in 20 patients (16 male, 60 ± 13 years) with an MI in the territory of the left anterior descending artery. Myocardial velocity data were measured in the interventricular septum and apical inferior segment of the MI territory. Postsystolic thickening was identified if the absolute velocity of PST was higher than peak systolic velocity in the presence of either a resting PST > 2.0 cm/s or if PST doubled at low-dose dobutamine infusion. Results: Doppler myocardial imaging data could be analyzed in 38 ischemic segments (95%), and PST was observed in 21 segments (55%), including 3 segments showing PST only at low-dose dobutamine infusion. There was no significant difference of baseline wall motion score index (2.1 ± 0.3 vs. 2.1 ± 0.6, p = 0.77) orpeak systolic velocity (1.1 ± 1.1 vs. 1.9 ± 2.0 cm/s, p = 0.05) between segments with and without PST. Peri-infarction ischemia or viability during DSE was more frequently observed in segments with PST than in those without (86 vs. 24%, p < 0.05). The sensitivity and specificity of P ST for prediction of peri-infarction viability or ischemia was 82 and 81%, respectively. Conclusions: Postsystolic thickening in the infarct territory detected by DMI is closely related with peri-infarction ischemia or viability at DSE. [source]