Natural history of "high-risk" bundle-branch block: final report of a prospective study.
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.
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000401:mortality; D001919:Bradycardia / Q000150:complications; D002037:Bundle-Branch Block / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D003327:Coronary Disease / Q000150:complications; D003645:Death, Sudden / Q000453:epidemiology; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000209:etiology* / Q000628:therapy; D006333:Heart Failure / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D012306:Risk; D013575:Syncope / Q000150:complications