The cardiac conduction system was examined histologically in 13 feline cases of hypertrophic cardiomyopathy (HCM) with complete atrioventricular (AV) block. Marked degeneration and fibrous replacement of the AV conduction system were consistently observed in the combined regions of the branching portion of the AV bundle and the upper portion of ...

Congenital complete heart block can be isolated or can occur in association with other structural heart diseases. Isolated congenital complete heart block (CCHB) is due to transplacental transfer of autoantibodies from mothers with connective tissue disease. Congenital heart block is usually complete, but incomplete blocks, sinus bradycardia and QTc prolongation ...

Why does the heart beat? This question--known as the myogenic versus neurogenic theory--dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that ...

Herpes zoster (shingles) is a reactivation of latent Varicella-zoster virus (VZV). We present a case of pleuropericarditis simulating acute myocardial infarction and another with complete heart block in the setting of acute/recent VZV reactivation. These cases are consistent with a modified concept: (1) the VZV dormancy is comprised of multiple ...

This case report describes transient atrioventricular block as the etiology for syncopal events in a 6-year-old male German shepherd dog with atrial fibrillation and dilated cardiomyopathy. The arrhythmia diagnosis was obtained via Holter monitoring. Medical treatment with a sustained-release preparation of theophylline, as an additive to the standard congestive heart ...

BACKGROUND: A left ventricular aneurysm (LVA) occurs between 3.5% and 9.4% of all cases of acute myocardial infarction. A fragmented left sided QRS (RSR; pattern or its variant RSr;, rSR;, or rSr;) without evidence of bundle branch block (QRS duration <or=120 ms) on the ECG may be associated with a ...

Accurate and computationally efficient means of classifying electrocardiography (ECG) arrhythmias has been the subject of considerable research effort in recent years. This study presents a comparative study of the classification accuracy of ECG signals using a well-known neural network architecture named multi-layered perceptron (MLP) with backpropagation training algorithm, and a ...

The study of the dissemination of the electrical impulse throughout the ventricular myocardium, which gave rise to the current theories, was carried out without taking into consideration the complex architecture of the cardiac muscle elucidated by more recent researchers. We propose a novel hypothesis based on the special macroscopic structure ...

BACKGROUND: The aim of this study was to evaluate normal subjects with isolated left bundle branch block (LBBB) using tissue Doppler imaging (TDI) for the presence of intraventricular asynchrony. METHODS AND RESULTS: For this purpose, 23 subjects with isolated LBBB were compared with age-matched asymptomatic healthy subjects without LBBB with ...

AIMS: The impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) on myocardial perfusion is not completely understood as data are often blurred by underlying cardiac disease. The present study investigates whether conduction delays per se affect coronary perfusion-an indirect measure of myocardial oxygen demand. METHODS ...

A 42-year-old man was admitted to our hospital with palpitation attacks. Holter ECG showed 2:1 atrioventricular block and bradycardia with the minimum heart rate of 44 beats/min. There was a possible indication of electrophysiological study and cardiac pacemaker implantation. Laboratory data on admission revealed elevated thyrotropin level, with normal thyroxine ...

This is a unique case of Merkel cell carcinoma, a rare neuroendocrine tumor, metastasizing to the heart and inducing a progression of cardiac complications such as new-onset atrial fibrillation, malignant pericardial effusion with tamponade physiology, first-degree heart block, and complete heart block. Metastases to the heart are relatively rare but ...

Alterations in microscopic conduction could contribute to microreentry and arrhythmogenesis in pathological settings. This chapter reviews microconduction in the ventricular myocardium. Gap junctions play a significant role in longitudinal and transverse propagation of the action potential wavefront in the ventricle. Studies of microscopic conduction in patterned cultures of neonatal rodent ...

Ellis-van Creveld syndrome is a rare autosomal recessive disorder caused by mutations in the EVC and EVC2 gene (4p16), characterized by chondrodystrophy, postaxial polydactyly, ectodermal dysplasia and cardiac anomalies. We present the case of a 24 years old female patient with unaffected parents and an affected sister, with a personal ...

In this study, we report the identification and amino acid sequence of a novel two-pore domain potassium channel (TASK-1) in chicken. This protein, cTASK-1, is highly similar to mouse and human TASK-1 particularly within the pore regions. We describe the expression profile of both chicken and mouse TASK-1 in the ...

This paper presents a method of automatic processing the electrocardiogram (ECG) signal for the classification of heart beats. Data were obtained from 48 records of the MIT-BIH arrhythmia database (only one lead). Five types of arrhythmic beats were classified using our method, Premature Ventricular Conduction beat (PVC), Atrial Premature Conduction ...

Electrocardiographic right bundle branch block morphology during cardiac pacing is occasionally the result of accidental placement of pacemaker or defibrillator leads into the left ventricle. Inadvertent lead placement in the left heart is associated with a risk of systemic embolism. Previous authors have attempted to define safe (right ventricular origin) ...

BACKGROUND: Left ventricular hypertrabeculation/noncompaction (LVHT) is a cardiac abnormality characterized by prominent trabeculations and intertrabecular recesses, and frequently associated with neuromuscular disorders (NMD). Initially described in children and young adults, LVHT has been found also in elderly. Aim of the study was to assess the age-dependency of clinical, electrocardiographic (ECG) ...

AIMS: To investigate the long-term fate of men with bundle-branch block (BBB) from a general population sample. METHODS AND RESULTS: Data were derived from 7392 men without a history of myocardial infarction or stroke, born between 1915 and 1925 and investigated between 1970 and 1973. All participants were followed from ...

BACKGROUND: Prolonged QRS duration (QRSd) is a useful index for the management of patients with congestive heart failure (CHF). QRSd is affected by changes in the ECG voltage (ECGV) in the context of development and amelioration of peripheral edema (PERE), independent of underlying pathology. Nowadays, physicians accept QRSd measured by ...

In patients with atrioventricular septal defect (AVSD), the occurrence of nonsurgical AV block has been reported. We have looked for an explanation in the development of the AV conduction system. Human embryos with AVSD and trisomy 21 and normal embryos were examined (age 5-16 wk gestation). Antibodies to human natural ...

A 45-year-old man who had been undergoing maintenance hemodialysis for end-stage renal failure, caused by chronic glomerulonephritis 4 years before, was admitted to our hospital for biventricular pacemaker implantation (BVP). Ten years ago, he was diagnosed with idiopathic dilated cardiomyopathy, and had been suffering from dialysis-related hypotension (DRH) due to ...

Knockout of the neural and cardiac expressed transcription factor HF-1b causes electrophysiological abnormalities including fatal ventricular arrhythmias that occur with increasing frequency around the 4th week of postnatal life. This study addresses factors that may contribute to conduction disturbance in the ventricle of the HF-1b knockout mouse. Disruptions to gap ...

Patients in intensive care often develop stress-induced ulcers. As a preventive measure, proton pump inhibitors (PPIs) are administered by nasogastric tube. However, some PPIs can block the tube. The aim of this study was to compare the behaviour of three PPIs (omeprazole, lanzoprazole and esomeprazole) during the transit of the ...

The role of electrocardiography in identifying right ventricular (RV) dysfunction in acute pulmonary embolism (APE) was evaluated in 81 patients with APE. The electrocardiographic markers studied were T-wave inversion in leads V1 to V3, the S1Q3T3 pattern, right bundle branch block, and sinus tachycardia. T-wave inversion in leads V1 to ...

INTRODUCTION: The relative importance of nonuniform dispersion of refractoriness, steep restitution slopes, and anatomic heterogeneities in causing conduction block during ventricular fibrillation (VF) remains unknown. METHODS AND RESULTS: In six open-chest pigs, ventricular refractoriness and restitution curves were estimated from activation recovery intervals (ARIs) calculated from 504 (21 x 24) ...

BACKGROUND: The determinants of bundle block patterns and their relationship to mortality in heart failure patients is not completely understood. METHODS: We evaluated 2907 consecutive patients admitted to an intensive care unit with decompensated heart failure over 8 years. Clinical and echocardiographic factors were analyzed using multivariate techniques. All-cause mortality ...

A case of a 51-year old male is presented. A left bundle branch block inferior axis tachycardia was manifest. At electrophysiological study this tachycardia was inducible and was ablated in the septal right ventricular outflow tract (RVOT). Two other tachycardias were identified both with right bundle branch block (RBBB) morphology ...

A case of complete atrioventricular (AV) block of congenital origin in a 16-month-old Holstein heifer was studied histologically with serial sectioning of the cardiac conduction system. The heart was enlarged and showed moderate dilatation of the left and right ventricles. Histologically, the abnormally placed and poorly formed AV bundle was ...

Two new, long-acting local anaesthetics have been developed after the evidence of bupivacaine-related severe toxicity: levobupivacaine and ropivacaine. Both these agents are pure left-isomers and, based on their three-dimensional structure, they have less toxic potential both on the central nervous system and on the heart. Several clinical studies have evaluated ...

Specialized conduction tissues mediate coordinated propagation of electrical activity through the adult vertebrate heart. Following activation of the atria, the activation wave is slowed down in the atrioventricular canal or node, after which it spreads rapidly into the left and right ventricles via the His-Purkinje system (HPS). This results in ...

BACKGROUND: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure prior to chick embryo incubation (GD 0) induces dilated cardiomyopathy, and reduces myocardial hypoxia, vascular endothelial growth factor A (VEGF-A) expression, and coronary vascularization. We investigated whether reduced coronary vascularization 1) occurs in the absence of changes in cardiac morphology and 2) is associated with altered ...

The frequencies of electrocardiographic (ECG) abnormalities and myocarditis were determined, retrospectively, among 154 cases of trichinellosis [101 males and 53 females, with a mean (S.D.) age of 35.60 (14.64) years] who were hospitalized at the University Hospital for Infectious Diseases in Zagreb, Croatia, over a 5-year period. Eighty-seven (56%) of ...

Although various manifestations of pentamidine-induced cardiotoxicity have been reported, to our knowledge, second-degree heart block associated with this agent has not been described. In addition, cardiac adverse effects usually develop after at least 6 days of therapy. We describe a 54-year-old, human immunodeficiency virus-positive man with a history of sulfonamide ...

BACKGROUND: The significant role of bundle branch block during atrioventricular nodal reentrant tachycardia (AVNRT) is not clear. The purposes of this study were to study the effects of complete right bundle branch block (RBBB) on electrophysiological parameters during AVNRT and to define the significance of complete RBBB during AVNRT. METHODS ...

OBJECTIVES: Fetal heart block is a rare and irreversible condition associated with structural heart defects or maternal autoantibodies (SS-A/Ro and SS-B/La) resulting in permanent damage of the atrioventricular (AV) node. This is the first report of 4 cases with a transient fetal heart block in structurally normal hearts without maternal ...

A patient with a family history of sudden cardiac death and a structurally normal heart presented with a resting ECG intermittently displaying a saddle-type Brugada-ECG, which could be reproducibly converted to a coved-type ECG pattern suggestive of Brugada syndrome. However, no ST-segment changes occurred in the presence of a true ...

Conduction defect caused by lamin A/C gene mutation. INTRODUCTION: Mutations of lamin A/C gene (LMNA) cause dilated cardiomyopathy (DCM) with atrioventricular (AV) conduction defect, although the electrophysiological and histological profiles are not fully understood. METHODS AND RESULTS: We analyzed a large Japanese family (21 affected and 203 unaffected members) of ...

Massive myocardial calcifications were detected by antenatal ultrasound examination in four second-trimester fetuses. In one fetus, multiple cardiac rhabdomyomas were the initial diagnosis. One fetus presented with arthrogryposis and the brain and spinal cord showed severe hypoxic-ischemic damage. One fetus was hydropic and had severe cardiac malformations. The fourth fetus ...

The influence of atrioventricular block (AV-block) on the trace elemental status in a horse hair was studied. The particle-induced X-ray emission (PIXE) method has provided a reliable, rapid, easy, and relatively inexpensive diagnostic method. Twenty-five elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Na, Nb, ...

Tricyclic antidepressants remain a common cause of fatal drug poisoning as a result of their cardiovascular toxicity manifested by ECG abnormalities, arrhythmias and hypotension. Dosulepin and amitriptyline appear to be particularly toxic in overdose. The principal mechanism of toxicity is cardiac sodium channel blockade, which increases the duration of the ...

Left axis deviation is one of the most commonly encountered ECG abnormalities. Its presence should alert medical directors and underwriters to the possibility of underlying structural heart disease. Many of the causes of left axis deviation are apparent from the clinical findings. Left anterior fascicular block is one of the ...

BACKGROUND: In the reperfusion era the clinical characteristics of intermediate QRS prolongation without bundle-branch block (BBB) remain unclear in patients with ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: A total of 465 patients with STEMI within 24 h of onset were classified into 3 groups according to QRS duration ...

BACKGROUND: Patients with left bundle branch block have a preserved right bundle branch conduction and the efficacy of left ventricular pacing could be explained with the fusion between artificial pulse delivered in the left lateral wall and the spontaneous right ventricular activation. Moreover, the efficacy of left ventricular pacing could ...

BACKGROUND: Isolated, asymptomatic first degree AV block with narrow QRS has not prognostic significance and is not usually treated with pacemaker implantation. In some cases, yet, loss of AV synchrony because of a marked prolongation of the PR interval may cause important hemodynamic alterations, with subsequent symptoms of heart failure. ...

BACKGROUND: Paroxysmal atrioventricular (AV) block is an ill-defined entity, previously described in sporadic cases in association with vasovagal reaction, coronary angiography and distal conduction disease. METHODS: We describe 20 patients (10 women) aged 26 to 80 years with symptomatic paroxysmal AV block. RESULTS: Eight patients had ischemic heart disease-three with ...

Around 11-12% of tympanostomy tubes are reported to become blocked by middle ear secretions or blood immediately following surgery, and so no longer function. Many otologists routinely instil an antibiotic and steroid-containing solution at the time of surgery in the belief that this may reduce this complication. The aim of ...

The anterior interventricular branch of the left coronary artery has the most constant distribution in the human heart and rarely gives off right ventricular branches. Here we report a case with a right ventricular branch which diverged from the anterior interventricular branch and descended on the anterior right ventricular wall ...

BACKGROUND: Cardiogram signal amplitude is a key index of hypertrophy but has not been investigated extensively in utero. In this study, magnetocardiography was used to assess P and QRS amplitude in normal subjects and subjects with fetal arrhythmia. METHODS AND RESULTS: The study cohort consisted of 68 normal fetuses and ...

Vagus nerve stimulation (VNS) is an important therapeutic option for individuals with refractory epilepsy who have failed multiple antiepileptic drugs (AEDs). The intricate relationship of the vagus nerve to cardiac function raises concern that vagal stimulation may affect cardiac rhythm and function. Previous pre- and postmarketing studies have not shown ...