Chronic bifascicular and trifascicular block was associated with a low 5-year mortality from possible bradyarrhythmia (6%) and a low incidence of heart block (19 of 554 patients).
Cohort (n=554)
In patients with chronic bifascicular and trifascicular block, the risk of progressing to heart block or dying from bradyarrhythmia is low, and most sudden deaths are due to tachyarrhythmia or myocardial infarction.
We conducted a prospective study in which 554 patients with chronic bifascicular and trifascicular conduction abnormalities were followed for an average of 42.4 +/- 8.5 months. Heart block occurred in 19 patients, and 17 were successfully treated. The actuarial five-year mortality from an event that could conceivably have been a bradyarrhythmia was 6 per cent (35 per cent from all causes). Of the 160 deaths 67 (42 per cent) were sudden; most of these were not ascribable to bradyarrhythmia but to tachyarrhythmia and myocardial infarction. Mortality was higher in patients with coronary-artery disease (P less than 0.01) and congestive heart failure (P less than 0.05). Patients in whom syncope developed before or after entry into the study had a 17 per cent incidence of heart block (2 per cent in those without syncope)(P less than 0.05); however, no single variable was predictive of which patients were at high risk of death from a bradyarrhythmia. The predictors of death were increasing age, congestive heart failure, and coronary-artery disease; the predictors of sudden death were coronary-artery disease and increasing age. The risks of heart block and of death from a bradyarrhythmia are low; in most patients, heart block can be recognized and successfully treated with a pacemaker.
McAnulty et al. (1982) conducted a cohort in Chronic bifascicular and trifascicular conduction abnormalities (n=554). Chronic bifascicular and trifascicular block was associated with a low 5-year mortality from possible bradyarrhythmia (6%) and a low incidence of heart block (19 of 554 patients).