SUMMARY In eleven patients in whom atrial premature stimulation elicited functional block in the conduction system distal to the atrioventricular (A-V) node, the influence of atrial driving rate was studied. Functional conduction disturbances in the left bundle branch-Purkinje system were produced by driving the atria at a rate just above the spontaneous sinus rate and by introducing premature ...

This study concerns two cases of chronic 2 degrees atrioventricular (A-V) block with left bundle branch block (LBBB). Pathological studies included serial section of the conduction systems. Case 1 had type I 2 degrees block with LBBB. Electrophysiological studies revealed type I 2 degrees block proximal to the His bundle recording site and a prolonged H-V interval (60 msec). Pathologically ther...

We describe the case of a 37-year-old woman who presented with complete right bundle branch block and right axis deviation. She was admitted to our hospital due to severe heart failure and was dependent on inotropic agents. Cardiac resynchronization therapy was initiated but did not improve her condition. After the optimization of the pacing timing, we performed earlier right ventricular pacing...

Filtered bipolar right ventricular apical (RVA) and His bundle electrograms, using electrodes only i mm apart, were recorded in two patients with intermittent WPW type A with and without 'complete' right bundle-branch block. In beats with exclusive normal pathway conduction and 'complete' right bundle-branch block, the HV and V-RVA intervals represented His-to-left ventricular endocardial and l...

A case of intraventricular trifascicular block secondary to an inferior myocardial infarction is reported. The case denonstrates instances of 2: I atrioventricular conduction due to alternating block in the right bundle-branch and block in the right bundle and both anterior and posterior divisions of the left bundle (trifascicular block). Instances of I: i AV conduction with grade I block and p...

Reentry within the His-Purkinje System (V3 phenomenon) where the reentry pathway incorporates both bundle branches and the bundle of His is a frequent phenomenon during ventricular refractory period studies. In this form of reentry, both divisions of the left bundle branch function as a single limb and the reentrant beats (V3) have either left bundle branch block or right bundle branch block pa...

Interruption of anterior fibers of the left bundle branch system together with right bundle branch block was accomplished experimentally in canine and primate hearts. In both species the electrocardiographic effects included a major alteration of the mean electrical axis to a superior and anterior direction. Epicardial excitation was markedly delayed anteriorly, causing widening of the QRS comp...

The antemortem diagnosis of myocardial sarcoidosis is rare in patients without overt signs of the disease. Two patients are presented to alert physicians to the value of early scalene node biopsy when sarcoidosis could be the cause of marked disturbances in cardiac conduction. The first patient, aged 29 years, had first, second, and third degree atrioventricular block and intermittent left and ...

background differentiating ischemic from nonischemic cardiomyopathy is important both prognostically and therapeutically, although it may be difficult clinically. objectives we aimed to determine the diagnostic power of cardiogoniometry (cgm) in the differentiation of the ischemic from the nonischemic etiology of left bundle branch block (lbbb). patients and methods we studied 37 patients with ...

Over a 3-year period of observation, the electrocardiogram in an adult patient with an ostium primum atrial septal defect changed from first-degree atrioventricular block alone to right bundle-branch block and left-axis deviation (left anterior hemiblock) with variable atrioventricular block. Coronary atherosclerosis was excluded by selective coronary arteriography. Although right bundle-branch...