OBJECTIVES: The aim of this study was to present bundle branch reentry as the mechanism of sustained ventricular tachycardia in the absence of myocardial or valvular dysfunction. BACKGROUND: Previous reports have documented the relation between structural heart disease and bundle branch reentrant ventricular tachycardia. Myocardial or valvular dysfunction has thus ...

The initiation of a reentrant circuit requires a zone of slow conduction and a zone of unidirectional block. This study used computer model conditions under which partial coupling between segments of cardiac Purkinje tissue resulted in unidirectional block. The structure used was one-dimensional and divided into three segments: a middle ...

LBBB obscures many cardiovascular diagnoses, but it is now possible to diagnose LVH and MI in the presence of LBBB. It is possible from accumulated data to synthesize a new clinical entity: The Complete Left Bundle Branch Block Syndrome. This encompasses the following: Uncomplicated LBBB: (1) the abnormal ECG configuration ...

This study describes the simulation of the more common types of conduction blocks with a computer model of the heart incorporating anisotropic propagation. The rationale was to test the model as to its ability to simulate these blocks by physiologically justifiable adjustments of the conduction system alone. The complete blocks ...

Chagas' disease is a chronic parasitosis affecting most Latin American countries. Its most important clinical manifestation is a late developing chronic myocarditis and, much less frequently, an early acute myocarditis. Chagasic myocardial damage is microfocal and disseminated throughout the heart. In most cases, the coexistence of areas of myocytic degeneration, ...

Present-day computer models of the entire heart, capable of simulating the activation isochrones and subsequently the body surface potentials, focus on considerations of myocardial anisotropy. Myocardial anisotropy enters into play at two levels, first by affecting the spatial pattern of activation owing to faster propagation along cardiac fibers and second ...

There were 160 incidents associated with regional anaesthesia amongst the first 2000 incidents reported to the Australian Incident Monitoring Study. They were categorised into 6 groups; epidural anaesthesia (83), spinal anaesthesia (42), brachial plexus blocks (14), intravenous local anaesthesia (4), ocular blocks (3), and local infiltration (14). The largest single ...

The prognostic value of electrocardiographic abnormalities has not been widely studied in the elderly. We examined the Minnesota code ECG items in 2254 elderly subjects of the Cardiovascular Study in the Elderly (CASTEL), performed on an Italian general population. In our experience, codes for ischaemia, 1st-degree atrio-ventricular block, bundle branch ...

The incidence of cardiac dysrhythmias is characterized in a group of 47 chronic SCI patients (greater than 30 days post injury; range 35-3605 days) with SCI lesions ranging from C4 to L3 who were referred for evaluation of a potential cardiac dysrhythmia by 24 hour Holter monitoring. Patients were grouped ...

BACKGROUND: Ventricular tachycardias occurring in the chronic phase of myocardial infarction are caused by reentry. Areas of slow conduction, facilitating reentry, are often found in the infarcted zone. The purpose of this study was to elucidate the mechanism of slow conduction in the chronic infarcted human heart. METHODS AND RESULTS: ...

The effects of acute ischemia on conduction velocities in the longitudinal (theta L) and transverse (theta T) fiber axis were determined from epicardial activation patterns, recorded with 48 bipolar electrodes (plaque electrode, 25 x 35 mm) on the left anterior ventricular wall of eight dogs and the posterior wall of ...

This report describes an unusual case of secondary nocturnal enuresis presumptively secondary to progressive bradycardia from complete heart block. Congenital complete heart block occurs in approximately 1 of 22,000 livebirths and is typically associated with structural congenital heart disease or maternal collagen vascular diseases. It can be entirely asymptomatic during ...

A new technique to block conduction from both atria to the atrio-ventricular node (A-V node) was devised through anatomical considerations of the junctional area. To assess the validity of the technique, a series of experiments were performed in mongrel dogs. Under cardiopulmonary bypass, the interatrial septum was incised along the ...

Our purpose was to test if pinacidil and bimakalim (EMD 52692 or SR 44866), which are ATP-sensitive K+ (K+ATP) channel openers, can attenuate bupivacaine-induced atrioventricular (AV) block. Bupivacaine-induced AV block was studied in 24 isolated guinea pig hearts with or without either pinacidil or bimakalim. Hearts were perfused at 55 ...

A 40-year-old man undergoing electrophysiologic study for recurrent palpitations was found to have a right bundle branch block during sinus rhythm and right bundle potentials occurring after ventricular activation. The sequence of activation of the proximal and distal right bundle potentials was suggestive of a retrograde invasion of the right ...

We report an extremely rare case of dilated cardiomyopathy manifested by exercise-induced left bundle branch block. A 63-year-old female came to our hospital because supraventricular arrhythmia had been detected at a check-up. A treadmill exercise test induced left bundle branch block. However, chest X-ray and echocardiography revealed no abnormal finding. ...

Dofetilide may induce aberrant intraventricular conduction due to its Class III effect. This report describes an atrial fibrillation patient in whom intraventricular conduction was studied before and after dofetilide using multiple endocardial recordings. Dofetilide provoked aberrant conduction during atrial fibrillation, and aberrancy could be mimicked with programmed atrial stimulation after ...

OBJECTIVE: To study the pattern of innervation of the conduction system of the neonatal heart in humans. DESIGN: A prospective analysis based on immunohistochemical and enzyme histochemical examination of newborn human hearts. SETTING: A general district hospital. MAIN OUTCOME MEASURES: Fresh necropsy tissue. MATERIAL: Hearts of three neonatal humans with ...

Surface electrocardiographic findings of 10 cases of left bundle branch block with echocardiographically determined left ventricular hypertrophy were compared with another 10 cases of left bundle branch block without left ventricular hypertrophy. Horizontal plane QRS- and T-wave angle > or = 150 degrees was highly sensitive (70%) and specific (90%) ...

The main goal of the present paper is to study the temporal and spatial course of cardiac electrical activation noninvasively, and to acquire more information than can be obtained from conventional methods, such as electrocardiography or vectorcardiography. The single moving resultant heart dipole is determined from a set of measured ...

We examined the electrophysiologic actions of BRB-I-28 using two in vivo and two in vitro models of myocardial ischemic injury. In intact canine heart studied 4 days after anterior descending coronary artery occlusion, BRB-I-28 (3 and 6 mg/kg, i.v.) prolonged refractoriness in ischemically injured epicardium to an extent similar to ...

To evaluate the significance of clinical, hemodynamic and electrocardiographic risk factors in idiopathic dilated cardiomyopathy 94 patients were followed prospectively for 49 +/- 37 months. During follow-up, 30 patients died, 13 died suddenly, 13 died of congestive heart failure and 4 of other causes. Follow-up was completed in 85 patients, ...

A simple catheterization technique for producing suppression or block of atrioventricular (AV) conduction in dogs by neodymium:YAG (Nd:YAG) laser photocoagulation from the aortic root is described. In 14 canines, electrode catheters were percutaneously advanced to the high right atrium, to the His bundle area at the tricuspid valve (right His ...

It is important to distinguish proximal right bundle branch block (RBBB) from distal RBBB because patients with both proximal RBBB and left bundle branch block may progress to a late atrioventricular conduction disturbance. Signal-averaged electrocardiograms (SAECGs) were investigated in 35 patients with RBBB following surgical correction of tetralogy of Fallot ...

Cardiac amyloidosis, an uncommon disease, has been reported to manifest as congestive heart failure (CHF) and/or various arrhythmias. Herein, we report a case of CHF and sick sinus syndrome. The patient, a 66-year-old man, was admitted to the National Taiwan University Hospital because of dizzy spells and recurrent syncope. Electrocardiogram ...

OBJECTIVE: To compare the different effects of right ventricular pacing and classic left bundle branch block on left ventricular function. DESIGN: Retrospective and prospective study of 48 patients by electrocardiography, and M mode, cross sectional, and Doppler echocardiography. SETTING: A tertiary cardiac referral centre. PATIENTS: 48 patients (age range 21 ...

The possibility of estimating infarct size with body surface QRST integral (IQRST) maps was investigated in dogs. IQRST maps were constructed from 87-lead body surface ECGs, which were recorded 1 week after the production of anterior myocardial infarction during artificial pacing that simulated normal conduction, left bundle branch block, and ...

The relationship between the angle formed by the left circumflex (LCX) and left anterior descending (LAD) coronary arteries at the bifurcation of the left main coronary artery (LM) and the location of sudanophilia in the proximal portions of the LCX and LAD, was investigated, using a normalized index of disease ...

Propranolol, a nonselective beta-adrenergic blocking agent, although prescribed frequently, has not been monitored for its adverse reactions in Indian population. A collaborative ADR monitoring study was planned in 2661 hypertensive patients. Exclusion criteria were associated circulatory insufficiency, heart block, left ventricular failure, diabetic mellitus and airway obstruction. The incidence of ...

The objectives of this retrospective study are to describe the effect of thrombolytic treatment on the clinical course of patients with acute anterior myocardial infarction complicated by acute right bundle branch block. Patients admitted to the intensive cardiac care unit within < 4 hours from onset of symptoms, and demonstrating ...

Acute atrioventricular (AV) block occurs frequently in patients with myocardial infarction. Atrioventricular block is also a common manifestation of sclerodegenerative conduction system disease. Occasionally, heart block results from drug toxicity, hyperkalemia, cardiac valvular calcification, myocarditis, or infiltrative cardiomyopathy. Second-degree AV block is a form of "incomplete" heart block, in which ...

Myocardial ischemia may decrease conduction velocity and produce QRS prolongation in the surface electrocardiogram. In cases with normal intraventricular conduction, areas of the myocardium contributing to the development of the S wave receive blood from all 3 major coronary arteries, whereas in left anterior hemiblock or right bundle branch block, ...

An experimental model of anisotropy was developed, consisting of a thin layer (1 mm) of perfused ventricular epicardium created by cryodestruction of the interventricular septum and the inner four-fifths of the free wall of the left ventricle. The electrophysiological properties of the 1-mm-thick surviving layer were the same as before ...

Eleven patients with an exercise dependent complete left bundle branch block (CLBBB) were followed-up over a period of 2-13 years (mean 6.5 +/- 3.8). Their ages ranged from 19 to 62 years (mean 48). Four patients complained of chest pain on effort and one of palpitations. All patients underwent a ...

We describe pathological abnormalities in a 72-year-old male member of a family with a congenital absence of sinus rhythm and a tendency to develop atrial fibrillation at an early age, and in a 54-year-old female member of a family with cardiomyopathy and progressive conduction system disease manifested by first-degree atrioventricular ...

The ECG is useful in diagnosing acute myocardial infarction and unrecognized Q-wave myocardial infarction in the elderly. Unrecognized myocardial infarction and myocardial infarction associated with clinical symptoms have a similar incidence of new coronary events. Ischemic ST-segment depression on the resting ECG is associated with an increased incidence of new ...

OBJECTIVES: Our goal was to compare histologically the mechanisms producing congenital complete heart block in normally structured hearts and in hearts with isomerism of the atrial appendages. BACKGROUND: It is known that several different histologic patterns can underscore the existence of congenital complete heart block in the normally structured heart, ...

The spatiotemporal distribution of the immunoreactivity of monoclonal antibody HNK-1 was investigated immunohistochemically in normal and bis-diamine-induced malformed rat embryonic hearts using three-dimensional reconstruction with computer graphics. First recognized in the primitive heart 11.5 days after conception, HNK-1 immunoreactivity was distributed in the atrio-ventricular and bulbo-ventricular junctional areas with incomplete ...

Three hundred forty consecutive patients (mean age 69 +/- 9 years) were evaluated with adenosine tomographic thallium-201 scintigraphy for suspected coronary artery disease. Minor side effects occurred in 91% of patients. Out of 28 patients (8%) with potentially serious side effects, 28 had significant atrioventricular (AV) block (second-degree, 24 patients; ...

This presentation reflects a case of phase-3 left bundle branch block (LBBB). Analysis reveals that relatively early QRS complexes are wide, whereas beats occurring later than a critical time are narrow. There are, however, two unexpected phenomena: (1) an overlap occurs between the range of R-R intervals resulting in normal ...

OBJECTIVES: The aim of this study was to determine the incidence and significance of second- or third-degree heart block among patients with inferior myocardial infarction treated with thrombolytic therapy. BACKGROUND: Data from the prethrombolytic era suggest that heart block occurs in approximately 20% of patients with acute inferior myocardial infarction ...

We report the electrocardiographic and electrophysiologic effects of magnesium (Mg) sulfate infusion in 25 normomagnesemic patients (16 men and 9 women, aged 22-74 years; mean +/- SD, 60.4 +/- 11.9) with different cardiac conduction impairments. Ten patients had chronic ischemic heart disease, two had idiopathic dilated cardiomyopathy, two had hypertensive ...

The development of complete heart block during left-sided cardiac catheterization is an uncommon event. We describe three cases of complete heart block complicating left-sided cardiac catheterization of patients with cardiac allografts. Review of the cases performed at our institution suggests that complete heart block during left-sided catheterization may be more ...

Eight of 120 consecutive patients with inducible sustained ventricular tachycardia who were studied at our institution from September 1, 1988 to January 1, 1991, were found to have reentry within the His-Purkinje System as the mechanism of their tachycardias. Two of the eight patients (25%) required the recording of the ...

A case report of a patient with persistent left anterior hemiblock admitted with acute ischemic heart disease is described. At effort during follow-up evaluation, the patient complained of retrosternal pain when the heart rate was 124 beats/min. No pathological ST-T changes were demonstrated at this time. At 133 beats/min, the ...

BACKGROUND: Reentry has been shown to be a mechanism of ventricular arrhythmias elicited by programmed premature stimulation in the subacute ischemic period of dogs subjected to myocardial infarction. The spatial distribution of refractoriness in these hearts has been shown to play an important part in the formation of functional arcs ...

A combined pathological and radiological study of descending aortae from 15 subjects from 2 to 80 yrs of age was conducted to investigate changes in the segmental vessels with advancing aortic atherosclerosis. There were (i) small hillocks of musculo-elastic intimal thickening adjacent to the apex (centre of the flow divider) ...

We present four patients with the Wolff-Parkinson-White syndrome who exhibited retrograde supernormal conduction or gap phenomenon in concealed accessory pathways. In the first patient, ventricular extrastimulus testing revealed retrograde block at the coupling interval of 520 msec and reappearance of conduction at the coupling interval of 370 msec. In a ...

To assess the incidence and clinical significance of ventricular late potentials in non-ischaemic dilated cardiomyopathy, 51 consecutive (44 male, seven female, mean age 53 +/- 11 years) patients with dilated cardiomyopathy were studied. Twenty-eight patients (55%) were in New York Heart Association functional class III or IV, 34 out of ...

In transverse and longitudinal paraffin-embedded sections, the human anterior cruciate ligament (ACL) is made up of wavy bundles of collagen fibres arrayed in various directions, the majority around the axis of the ligament with a few running parallel to it. The fascicles making up the larger bundles are also characterised ...