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Natural history of "high-risk" bundle-branch block: final report of a prospective study
Insights
The risk of heart block and bradyarrhythmia death is low in patients with conduction abnormalities. Most heart block cases are treatable with pacemakers, though sudden death is often linked to other cardiac issues.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Chronic bifascicular and trifascicular conduction abnormalities affect numerous patients.
- Understanding the long-term prognosis and risks associated with these conditions is crucial for patient management.
Purpose of the Study:
- To prospectively evaluate the incidence of heart block and bradyarrhythmia-related mortality in patients with chronic bifascicular and trifascicular conduction abnormalities.
- To identify predictors of mortality and sudden death in this patient cohort.
Main Methods:
- Prospective follow-up of 554 patients with chronic bifascicular/trifascicular conduction abnormalities for an average of 42.4 months.
- Analysis of heart block incidence, bradyarrhythmia-related mortality, all-cause mortality, and sudden death.
- Statistical analysis to identify predictors of adverse events, including syncope, coronary artery disease, and congestive heart failure.
Main Results:
- Heart block occurred in 19 patients (17 successfully treated); 5-year mortality from bradyarrhythmia was 6% (35% all-cause).
- Sudden death (42% of 160 deaths) was mainly due to tachyarrhythmia and myocardial infarction, not bradyarrhythmia.
- Mortality and sudden death were significantly higher in patients with coronary artery disease and congestive heart failure. Syncope predicted heart block.
- Increasing age, congestive heart failure, and coronary artery disease predicted overall death; coronary artery disease and increasing age predicted sudden death.
Conclusions:
- The risks of heart block and death from bradyarrhythmia are low in patients with chronic conduction abnormalities.
- Heart block is generally recognizable and treatable with pacemakers.
- Coronary artery disease and congestive heart failure are significant predictors of mortality and sudden death in this population.
Abstract:
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.