[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries].
OBJECTIVE
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.


METHODS
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.
Candell Riera
Jaume
J
Servicios de Cardiología y Medicina Nuclear. Hospital Universitari Vall d'Hebron. Barcelona. Spain. jcandell@hg.vhebron.es
Oller Martínez
Guillermo
G
Vega
Juan
J
Gordillo
Enrique
E
Ferreira
Ignacio
I
Peña
Carlos
C
Castell
Joan
J
Aguadé
Santiago
S
Soler Soler
Jordi
J
D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D015899:Tomography, Emission-Computed, Single-Photon