Clinical and angiographic importance of right bundle branch block in the setting of acute anterior myocardial infarction.
OBJECTIVE
To investigate functional status of patients (Killip class), left ventricular contractility, angiographic anatomy and severity of coronary lesions in patients with and without right bundle branch block (RBBB) in the setting of anterior myocardial infarction (MI).


METHODS
Patients who admitted to coronary care unit with the diagnosis of acute anterior MI between 1999 and 2005 were retrospectively searched from our database. Out of 792 patients, 37 had RBBB (RBBB group) either at admission or in the course of anterior MI. Forty patients who developed no intraventricular conduction defect during the course of anterior MI with the same demographic characteristics were selected as the control group.


RESULTS
Out of 37 patients, 30 had RBBB on admission and 7 developed RBBB in the course of acute MI. Left anterior descending artery (LAD) proximal lesion was more commonly detected in the RBBB group [23 (62.2%) vs. 11 (27.5%) patients, p=0.003]. Left ventricular ejection fraction was lower (33.0+/-4.2% vs 36.7+/-4.9%, p=0.003) and end-systolic volume was higher (84.1+/-24.9 ml vs 74.6+/-22.0 ml, p=0.012) in patients with RBBB. Number of patients with high Killip grade (III and IV) was more in the RBBB group [7 (18.9%) vs 3 (7.5%), RR: 1.75, %95 CI 0.92-3.32, p=0.14], and number of patients with Killip grade I was more in the control group [34 (85.0%) vs 22 (59.5%), p=0.012]. Besides mean Killip class was higher in the RBBB group (1.65+/-0.90 vs 1.25+/-0.67, p=0.03). Three patients (8.1%) in the RBBB group and 2 patients (5.0%) in the control group died during hospitalization (p=0.67).


CONCLUSIONS
Left ventricular ejection fraction decreases and Killip grade increases in case of RBBB in the setting of acute anterior MI. Culprit lesion in patients with RBBB is more commonly a LAD proximal lesion and threatened myocardial tissue is larger in patients with RBBB.
Arslan
Uğur
U
Department of Cardiology, Faculty of Medicine, Gazi University, Ankara, Turkey. ugurarslan5@yahoo.com
Balcioğlu
Serhat
S
Tavil
Yusuf
Y
Ozdemir
Murat
M
Cengel
Atiye
A
D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*