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Calcium channel blockade does not offer adequate protection from perioperative myocardial ischemia
F Chung1, P L Houston, D C Cheng
1Department of Anaesthesia, Toronto Western Hospital, Ontario, Canada.
Insights
Patients undergoing coronary bypass grafting who received calcium entry blockers alone showed more frequent perioperative ischemic ECG changes and higher heart rates compared to those on beta-blockers.
Area of Science:
- Cardiology
- Anesthesiology
- Pharmacology
Background:
- Perioperative myocardial ischemia is a significant concern in patients undergoing coronary bypass grafting (CABG).
- The use of beta-adrenergic blocking drugs and calcium entry blocking drugs is common in cardiac patients.
- Understanding the differential effects of these drug classes on hemodynamic and electrocardiographic responses during CABG is crucial for optimizing patient care.
Purpose of the Study:
- To compare the hemodynamic and electrocardiographic responses during the prebypass period in CABG patients receiving beta-adrenergic blockers, calcium entry blockers, or both.
- To identify potential differences in the incidence of myocardial ischemia based on preoperative medication regimens.
Main Methods:
- Prospective observational study involving patients undergoing CABG.
- Monitoring of hemodynamic parameters and electrocardiographic (ECG) findings during the prebypass period.
- Categorization of patients based on preoperative medication: beta-adrenergic blockers, calcium entry blockers, or combination therapy.
Main Results:
- Patients receiving calcium entry blockers alone exhibited a significantly higher frequency of electrocardiographic evidence of myocardial ischemia at induction of anesthesia, skin incision, and sternotomy.
- Heart rate at sternotomy was significantly higher in the calcium entry blocker group compared to the beta-adrenergic blocker group or the combination group.
- The incidence of perioperative ischemic ECG changes was significantly greater in patients treated with calcium entry blockers alone.
Conclusions:
- Preoperative treatment with calcium entry blockers alone is associated with an increased risk of perioperative myocardial ischemia during CABG.
- Beta-adrenergic blocking drugs, whether alone or in combination with calcium entry blockers, appear to offer greater protection against perioperative ischemic ECG changes in this patient population.
- These findings suggest that medication management strategies should be carefully considered in patients undergoing CABG to mitigate ischemic events.
Abstract:
This study aimed to detect the difference in hemodynamic and electrocardiographic responses during the prebypass period in patients undergoing coronary bypass grafting who were receiving beta-adrenergic blocking drugs, calcium entry blocking drugs, or both beta-adrenergic and calcium entry blocking drugs. Electrocardiographic evidence of myocardial ischemia was noted significantly more frequently in patients receiving calcium entry blocking drugs alone at induction of anesthesia (P less than 0.03), skin incision (P less than 0.05), and sternotomy (P less than 0.002). Heart rate at sternotomy was significantly higher in patients receiving calcium entry blocking drugs (P less than 0.02) as compared to patients receiving beta-adrenergic blocking drugs or the combination of both drugs. In conclusion, patients treated with calcium entry blocking drugs alone had significantly higher incidence of perioperative ischemic ECG changes compared with patients receiving beta-adrenergic blocking drugs alone or in combination with calcium channel blocking drugs.