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Coronary pathology predicts conduction disturbances after coronary artery bypass grafting
1Department of Cardiology, Hadassah University Hospital, Jerusalem, Israel.
Insights
Coronary artery bypass grafting can cause conduction disturbances if the septal artery is compromised. Preoperative angiography can predict this risk, particularly in patients with specific left anterior descending artery lesions.
Area of Science:
- Cardiology
- Cardiac Surgery
- Vascular Anatomy
Background:
- Conduction disturbances following coronary artery bypass grafting (CABG) are a known complication.
- Compromised blood flow to the septal perforator branches of the left anterior descending coronary artery is a suspected cause.
Purpose of the Study:
- To investigate the relationship between preoperative coronary artery anatomy and the incidence of conduction disturbances after CABG.
- To determine if specific angiographic findings predict post-CABG conduction abnormalities.
Main Methods:
- Retrospective review of preoperative coronary angiograms in 55 patients undergoing CABG.
- Classification of patients into Type I (no or non-obstructive septal perforator lesion) and Type II (lesion compromising septal perforator flow) anatomy.
- Correlation of anatomical type with post-CABG conduction disturbances.
Main Results:
- No major conduction disturbances occurred in 35 patients with Type I anatomy.
- Eleven of 20 patients with Type II anatomy developed major conduction disturbances (e.g., bundle branch blocks, AV block).
- Conduction disturbances in Type II patients correlated with absent retrograde septal branch flow from the right coronary artery.
Conclusions:
- Pathological lesions in the left anterior descending coronary artery affecting septal perforator blood flow can cause localized damage and conduction disturbances post-CABG.
- Preoperative angiographic assessment of septal artery anatomy is crucial for predicting the risk of conduction disturbances after CABG.
Abstract:
Conduction disturbances after coronary artery bypass grafting may result from compromised septal blood flow. To examine this hypothesis we reviewed the preoperative coronary angiography of 55 consecutive patients undergoing coronary artery bypass grafting. Thirty-five patients had either no lesion or a discrete lesion in the left anterior descending coronary artery that did not include the septal perforator (type I anatomy). Twenty patients had a lesion of the left anterior descending coronary artery at the origin of the first septal branch, a lesion of the first septal artery, or a pair of lesions in the left anterior descending coronary artery that straddled the origin of the first septal artery; all lesions were proximal to the graft site (type II anatomy). None of the patients with type I anatomy had a major conduction disturbance after coronary artery bypass grafting. Eleven of the patients with type II anatomy had major conduction disturbances after coronary artery bypass grafting; right bundle-branch block in 1, right bundle-branch block and left anterior hemiblock in 2, left bundle-branch block in 5, and complete atrioventricular block that required pacemaker implantation in 3 (p less than 0.001). In the 20 patients with type II anatomy, the appearance of conduction disturbances correlated well with the absence of retrograde flow to the septal branches from the right coronary artery (p less than 0.01). Pathological lesions in the left anterior descending coronary artery that compromise flow in the first perforator and that do not provide an adequate circulation produce localized damage and conduction disturbances after coronary artery bypass grafting. This can be predicted from the preoperative angiographic anatomy.