Significance of A-H interval in patients with chronic bundle branch block. Clinical, electrophysiologic and follow-up observations.

摘要: His bundle electrograms were recorded in 308 adults with chronic branch block. The A-H interval was normal 249 patients and prolonged 59. Comparison of intervals revealed a greater incidence demonstrable organic heart disease the latter (P less than 0.01). Dyspnea, cardiomegaly congestive failure more frequent prolongation. These also had longer P-R atrioventricular (A-V) nodal effective refractory periods, lower paced rates producing second degree A-V block proximal to frequency H-V All prospectively followed up conduction clinic mean follow-up periods (+/- standard error mean) 523 +/- 23 588 47 days intervals, respectively. Seven (3 percent) probable or definite site three distal four. In five six who experienced (10 percent), bundle. Mortality (both sudden nonsudden) not significantly different intervals. summary, prolongation associated increased myocardial dysfunction. risk development but appeared be minimal clinical significance.