Survival in patients with intraventricular conduction defects

Area of Science:

• Cardiology
• Electrophysiology
• Public Health

Background:

• Bundle branch blocks (BBB) are common electrocardiogram (ECG) findings.
• Left bundle-branch block (LBBB) and right bundle-branch block (RBBB) with axis deviation (AD) represent significant conduction abnormalities.
• Long-term survival data for patients with these specific ECG findings are limited.

Purpose of the Study:

• To determine the five-year survival rate of patients diagnosed with LBBB or RBBB with AD.
• To compare the survival rates of these patients with age- and sex-matched controls.
• To explore factors influencing survival, such as syncope and underlying cardiac conditions.

Main Methods:

• Retrospective review of 42,000 electrocardiograms (ECGs) from 1969-1971.
• Identification of 325 patients with LBBB or RBBB and AD (0.77% prevalence).
• Actuarial survival analysis conducted in 1974, with 90% of patients contacted or confirmed deceased.

Main Results:

• The overall five-year survival rate for patients with LBBB or RBBB and AD was 45.5%, significantly lower than controls.
• Survival rates for LBBB patients (40.7%) and RBBB with AD patients (49.5%) were not significantly different from each other.
• Patients with coronary artery disease had a lower five-year survival (33.7%) compared to those with primary conduction system disease (50.6%).
• Presence of syncope did not significantly impact survival rates.

Conclusions:

• LBBB or RBBB with AD is associated with a poor long-term prognosis.
• Coronary artery disease is a significant negative prognostic factor in this patient group.
• Further investigation into the causes of death and syncope is crucial for understanding potential interventions, such as pacemakers.