INTRODUCTION AND OBJECTIVES Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block. PATIENTS AND METHOD 9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and ev...

Accurate branch prediction and instruction fetch prediction of a microprocessor are critical to achieve high performance. For a processor which fetches and executes multiple instructions per cycle, an accurate and high bandwidth instruction fetching mechanism becomes increasingly important to performance. Unfortunately, the relatively small basic block size exhibited in many general-purpose app...

Alternating bundle branch block (ABBB) is a less commonly encountered phenomenon with the advent of re-perfusion therapy for acute myocardial infarction. ECGs simulating the appearance of an ABBB need to be carefully analysed. We present an ECG showing a baseline Left Bundle Branch Block(LBBB) progressing to a high grade AV block with escape complexes having a Right Bundle Branch Block (RBBB) m...

During the past five years 161 cases of bundlebranch block have been seen in the Cardiac Department of St. Vincent's Hospital. These patients have been evaluated clinically in an attempt to identify all possible associated and causative factors. This communication deals with these various factors and attempts to identify their relative importance in the genesis of both types of conduction defec...

Two patients who developed left bundle-branch block with increase in heart rate are presented. Atrial pacing during His bundle recording studies showed differing responses in the ventricular specialized conduction system of the two patients. In one, the onset of left bundle-branch block was associated with no change in the previously normal HVinterval (so msec), while in the second the HV inter...

BACKGROUND Definitive diagnosis of bilateral bundle-branch delay/block may be made when catheter-induced right bundle-branch block (RBBB) develops in patients with baseline left bundle-branch (LBB) block. We hypothesized that a RBBB pattern with absent S waves in leads I and aVL will identify bilateral bundle-branch delay/block. METHODS AND RESULTS Fifty patients developing transient RBBB pat...

Simultaneous tracings of right and left ventricular leads were taken in 6 dogs with experimentally produced left bundle-branch block, and in 30 clinical cases of left ventricular hypertrophy. In the experimental study it was found that the initial phase of the QRS complex in the right epicardial lead did not change its configuration or its duration after the production of left bundle-branch blo...

The main ventricular conducting fascicles were slightly injured in anesthetized dogs by gently scratching them with a blunt needle introduced through the ventricular wall. Initially the bundle branch block that resulted was rate independent (stage 1). When conduction returned to normal, both premature atrial and vagal stimulation reproduced the bundle branch block (stage 2). During stage 2 (5-1...

Complete right bundle branch block manifests with a rSR' configuration in right orientated leads and a duration of 0.12 sec or longer. Incomplete right bundle branch block is perceived as this classic rSr' configuration and a duration of less than 0.12 sec. This presentation reflects the early development of right bundle branch block which first manifests with a hitherto undescribed sign, namel...

To validate the accuracy of catheter endocardial mapping to localize the origin of ventricular tachycardia (VT), we compared cathether endocardial mapping with intraoperative epicardial and endocardial mapping of 24 morphologically distinct VTs in 18 patients undergoing surgery. Twelve had VT with left bundle branch block morphology and 12 had VT with right bundle branch block morphology. Cathe...