title: Exercise-induced left bundle branch block and its relation to coronary artery disease.
abstract: The records of 2,584 consecutive patients who underwent both treadmill exercise testing and coronary cineangiography were reviewed to determine the relation between exercise-induced, acceleration-dependent left bundle branch block (LBBB) and the presence of coronary artery disease (CAD). Rate-dependent LBBB during exercise was identified in 28 patients (1.1%), who were categorized according to their presenting symptoms: classic angina pectoris, atypical chest pain, symptomatic cardiac arrhythmia and asymptomatic. Asymptomatic patients underwent a screening exercise test. CAD was present in 7 of 10 patients who presented with classic angina pectoris, but 12 of 13 patients presenting with atypical chest pain had normal coronary arteries. All 10 patients in whom LBBB developed at a heart rate of 125 beats/min or higher were free of CAD, whereas 9 of 18 patients in whom LBBB developed at a heart rate of less than 125 beats/min had CAD. Normal coronary arteries were present in 3 patients who presented with angina and in whom both chest pain and LBBB developed during exercise. It is concluded that patients who present with atypical chest pain in whom rate-dependent LBBB develops on the treadmill are significantly less likely to have CAD than patients who present with classic angina; the onset of LBBB at a heart rate of 125 beats/min or higher is highly correlated with the presence of normal coronary arteries, regardless of patient presentation; and patients with angina in whom both chest pain and LBBB develop during exercise may have normal coronary arteries.
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000209:etiology; D002037:Bundle-Branch Block / Q000209:etiology* / Q000503:physiopathology; D006328:Cardiac Catheterization; D002932:Cineangiography; D017023:Coronary Angiography; D003327:Coronary Disease / Q000150:complications* / Q000503:physiopathology; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D005082:Physical Exertion; D012189:Retrospective Studies; D013909:Thorax