His bundle electrograms were obtained at rest during atrial pacing in 16 patients with congestive cardiomyopathy. Increments in heart rate during atrial pacing were associated with progressive increases in the A-H interval in all patients. Three patients had abnormal conduction (prolonged P-H) proximal to the His bundle; atrial pacing resulted in second degree A-V block (A-H block) in these three patients at paced rates below 130/min; these three patients were on digitalis at the time of the study. Two patients had left bundle branch block associated with a prolonged H-V interval suggesting a conduction disturbance in the contralateral bundle system either at or distal to the branching portion of the His bundle. Two patients had H-V prolongation in the presence of a normal QRS duration which suggests delay in the bundle of His. Two patients with normal H-V intervals had marked prolongation of the total intraventricular conduction time (H-S prolongation). The His bundle electrogram uncovered abnormalities in atrioventricular conduction not apparent on the standard electrocardiogram and has allowed expansion of our knowledge regarding the electrophysiologic features of congestive cardiomyopathy.
|Original language||English (US)|
|Number of pages||8|
|Journal||European Journal of Cardiology|
|State||Published - Jan 1 1975|
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