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Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block
Insights
Patients with right bundle branch block and left anterior fascicular block face higher mortality risks. This study highlights the importance of considering these blocks in cardiac risk assessment.
Area of Science:
- Cardiology
- Electrophysiology
- Clinical Research
Background:
- Right bundle branch block (RBBB) and left anterior fascicular block (LAFB) are common electrocardiographic abnormalities.
- Their association with long-term mortality and morbidity requires further investigation.
Purpose of the Study:
- To evaluate the excess mortality and morbidity associated with RBBB and LAFB.
- To assess the natural history of these conduction abnormalities.
Main Methods:
- A case-control study involving 108 patients with RBBB/LAFB and 108 matched controls.
- Life table analysis was used to compare 12-year mortality rates.
Main Results:
- Patients with RBBB/LAFB exhibited a significantly higher 12-year mortality risk (risk ratio 1.47, p < 0.05).
- Increased rates of sudden death and deaths of unknown cause were observed in the block group.
- Development of new atrioventricular block and coronary artery disease was more frequent in patients with conduction blocks.
Conclusions:
- RBBB and LAFB are associated with increased long-term mortality, even after accounting for heart failure.
- These findings underscore the prognostic significance of conduction abnormalities.
- Prophylactic pacing is not supported for asymptomatic patients based on these results.
Abstract:
Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block were evaluated in 108 patients with block (age 74 +/- 10 years, 69% male) and 108 age- and sex-matched control patients with normal conduction. Clinical characteristics were similar initially except for more congestive heart failure in patients with block. Life table analysis revealed a higher 12 year mortality with block, even after omitting patients with moderate or severe congestive heart failure (risk ratio 1.47, p less than 0.05). Compared with control subjects, the group of patients with block had more sudden death and deaths of unknown cause, but a similar number of noncardiac and diagnosed cardiac deaths. More patients with block developed new second and third degree atrioventricular block or new overt coronary artery disease, but this finding did not support prophylactic pacing in asymptomatic patients. The importance of internal controls in assessing the natural history of clinical and electrocardiographic abnormalities is emphasized.