Significance of right bundle branch block in the diagnosis of myocardial ischemia in patients undergoing coronary artery bypass grafting.
BACKGROUND
Perioperative diagnosis of myocardial ischemia following cardiac surgical procedures remains a challenging problem. Particularly, the role of new conduction disturbances as markers of postoperative ischemia is still questionable. The goal of this study was to elucidate the diagnostic significance of new postoperative right bundle branch block (RBBB) for the detection of perioperative myocardial ischemia in patients undergoing elective coronary artery bypass grafting (CABG).


METHODS
In 169 consecutive patients, three-channel Holter monitoring and serial assessment of serum enzymes were performed for 48 h, and 12-lead ECG repeated for up to 5 days postoperatively. Postoperative events were classified as either myocardial infarction (MI), transient ischemic events (TIE) or various conduction disturbances.


RESULTS
Transient (n=9) or permanent (n=4) RBBB occurred in 13 patients (8%); 14 patients (8%) showed signs of perioperative MI and 18 patients (11%) evidence of TIE. Peak activity of creatine-kinase (CK, 561+/-135 vs. 316+/-19, P<0.05) and CK-MB (22.7+/-3.2 vs. 13.4+/-0.8, P<0.01) were higher in patients with RBBB than in patients without perioperative ischemic events. Peak CK-MB levels were significantly higher in patients with MI as compared to those with RBBB (33.4+/-7.6 vs. 22.7+/-3.2, P<0. 05). Patients with TIE had similar perioperative enzyme levels as patients with no events.


CONCLUSIONS
It is concluded that the combined assessment of repeated 12-lead ECG, continuous Holter monitoring and enzyme analysis allows a reliable diagnosis of perioperative myocardial ischemia and conduction disturbances. The occurrence of new RBBB following elective CABG is indicative of perioperative myocardial necrosis and thus serves as a valuable tool for the diagnosis of new, perioperative ischemic events.
Department of Cardiothoracic Surgery, University of Vienna, AKH Vienna, Währingergürtel 18-20, 1090, Vienna, Austria. seitel@magnet.at
R
R
Seitelberger
T
T
Wild
N
N
Serbecic
S
S
Schwarzacher
M
M
Ploner
A
A
Lassnigg
B
B
Podesser
D015415:Biomarkers / Q000097:blood; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D001026:Coronary Artery Bypass; D003402:Creatine Kinase / Q000097:blood*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis* / Q000201:enzymology / Q000601:surgery; D011379:Prognosis; D012680:Sensitivity and Specificity
D015415:Biomarkers; D007527:Isoenzymes; D003402:Creatine Kinase