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[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal
Jaume Candell Riera1, Guillermo Oller Martínez, Juan Vega
1Servicios de Cardiología y Medicina Nuclear. Hospital Universitari Vall d'Hebron. Barcelona. Spain. jcandell@hg.vhebron.es
Insights
Exercise-induced left bundle-branch block with normal coronary arteries has a good prognosis, though permanent block may develop. Patients with coronary artery disease face higher risks.
Area of Science:
- Cardiology
- Electrophysiology
- Exercise Physiology
Background:
- Exercise-induced left bundle-branch block (LBBB) can occur without coronary artery disease.
- Understanding the clinical course of rate-dependent LBBB is crucial for patient management.
Purpose of the Study:
- To analyze the clinical characteristics and long-term evolution of patients diagnosed with exercise-induced LBBB.
- To differentiate outcomes based on the presence or absence of coronary artery disease.
Main Methods:
- Retrospective analysis of 9,318 exercise stress tests.
- Detailed review of 20 patients with exercise-induced LBBB who underwent coronary angiography.
- Mean follow-up duration of 6.9 years.
Main Results:
- Eight patients had normal coronary arteries (Group A), 12 had coronary artery disease (Group B).
- Group A showed higher peak oxygen consumption and heart rate at block onset (132 bpm vs 95 bpm).
- Group A patients with chest pain and normal coronaries had a good prognosis, but 5 developed permanent LBBB; Group B had 3 deaths and 2 myocardial infarctions.
Conclusions:
- Patients with exercise-induced LBBB and normal coronary arteries generally have a favorable prognosis, especially when experiencing chest pain.
- Permanent LBBB is a frequent outcome in patients with normal coronary arteries.
- Atrioventricular block is a rare but possible complication in patients with exercise-induced LBBB.
Introduction And Objectives:
Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block.
Patients And Method:
9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and evolution (mean follow-up: 6.9 years) of 20 patients with exercise-induced left bundle-branch block in which coronary angiography had been performed were analyzed.
Results:
Eight out of 20 patients had normal coronary arteries (group A) and 12 had coronary artery disease (group B). Peak O2 consumption, peak myocardial O2 consumption, and heart rate when block appeared (132 20 vs. 95.4 23 beats/min; p = 0.002) were significantly higher in group A. Seven of the 8 patients with normal coronary arteries had chest pain coinciding with the first beat of left bundle-branch block. There were no deaths during follow-up in group A, but permanent left bundle-branch block appeared in 5 patients of this group who experienced disappearance of exercise-related pain. There were 3 deaths in group B and 2 patients had acute myocardial infarction during follow-up. One patient in each group developed atrioventricular block and required pacemaker implantation.
Conclusions:
In contrast with patients with left bundle-branch block and coronary artery disease, the prognosis of patients with painful left bundle-branch block and normal coronary arteries is good. However, the development of permanent left bundle-branch block is frequent. Atrioventricular block, although rare, may occur.