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Predictors of conduction disturbances after coronary bypass grafting
M Hippeläinen1, P Mustonen, H Manninen
1Department of Surgery, Kuopio University Hospital, Finland.
Insights
Excessively low myocardial temperatures during cardiac surgery may lead to conduction disturbances (CD). Left main coronary artery stenoses also predict permanent CD, highlighting temperature management importance.
Area of Science:
- Cardiovascular Surgery
- Cardiac Electrophysiology
Background:
- Conduction disturbances (CD) are a complication of coronary artery bypass grafting (CABG).
- Predictors of CD, including coronary pathology and intraoperative factors, require further investigation.
Purpose of the Study:
- To investigate the effect of coronary pathology on CD after CABG.
- To identify preoperative and intraoperative predictors of permanent CD.
Main Methods:
- Prospective study of 169 patients undergoing CABG.
- Classification of interventricular septum vascularization using Mosseri's system.
- Analysis of preoperative and intraoperative data, including myocardial temperatures and creatine kinase MB levels.
Main Results:
- Type II coronary pathology, affecting septum revascularization, correlated with coronary disease severity but not CD.
- Permanent CD (34%) was associated with left main coronary artery stenoses (p=0.03).
- Lower myocardial temperatures and higher creatine kinase MB levels were observed in patients with permanent CD.
- Left circumflex artery region temperature and left main coronary artery stenoses independently predicted permanent CD.
Conclusions:
- Coronary pathology classification did not predict conduction disturbances.
- Excessively low myocardial temperatures during cardioplegia are a significant predictor of permanent CD.
- Left main coronary artery stenoses are also an independent predictor of permanent CD.
Abstract:
One hundred sixty-nine patients undergoing coronary artery bypass grafting were included in a prospective study to test the effect of coronary pathology on conduction disturbances (CD). At the same time, several other proposed preoperative and intraoperative predictors of CD were collected. From the angiograms, the vascularization of the interventricular septum was classified according to Mosseri and colleagues. Ninety-four patients (56%) had type II coronary pathology, which does not allow full revascularization of the interventricular septum. The tested classification did correlate with the state of coronary disease, resulting in more left main coronary stenoses and more numerous peripheral anastomoses in type II patients. However, there was no correlation between the classification and CD. Patients with permanent CD (34%) had more left main coronary artery stenoses (29% versus 14%; p = 0.03). Their measured maximal myocardial temperatures were lower in all three myocardial regions measured (p = 0.01 to 0.07), and their creatine kinase MB fraction values on the day of operation were also higher (92 versus 70 IU; p = 0.002). In multivariate logistic regression analysis, the maximal temperature of the left circumflex artery region and the presence of left main coronary artery stenoses were the only independent predictors of permanent CD. We conclude that excessively low myocardial temperatures during cardioplegia may cause CD.