Comparing perioperative magnesium sulphate, lidocaine, and their combination in preventing ventricular arrhythmia in off-pump coronary artery bypass grafting

Background
Techniques of coronary artery bypass grafting (CABG) have developed rapidly over the last decades. However, dysrhythmia is a common feature during off pump CABG. The aim of this work was to study effect of perioperative magnesium sulphate infusion on the incidence of cardiac arrhythmia in off-pump CABG: and comparing such effects to lidocaine alone or combined to magnesium.
Methodology
Ninety patients undergoing elective coronary artery bypass grafting surgery were randomly divided into three equal groups: magnesium group received magnesium over 12 h prior to off-pump surgery and over 30 min intraoperatively; lidocaine group were given an intravenous bolus injection of lidocaine followed by a continuous infusion; and combination group received half the doses of magnesium and lidocaine prescribed for the other two groups. The patients’ perioperative hemodynamic data (heart rate and mean arterial pressure) and the occurrence of intraoperative and postoperative arrhythmia were recorded.
Results
There was statistically significant difference between study groups as regards mean intraoperative heart rate and intraoperative mean arterial pressure. In addition, the need for intraoperative beta-blockers was significantly higher in lidocaine group; there was no need for intraoperative beta-blockers for combination group. Also, the need for perioperative aortic balloon pump was significantly higher in lidocaine group (20.0%), followed by 6.7% in magnesium group, and none in combination group. The percentage of ventricular tachycardia was significantly higher in lidocaine group (16.7%), followed by magnesium group (3.3%) and none in combination group.
Conclusion
Results of the present study revealed that combination of both perioperative magnesium and lidocaine when compared to each of both drugs separately has a better effect in controlling hemodynamics (heart rate and mean arterial blood pressure intraoperatively), less ventricular tachycardia, and reduction in the need for beta blockers and aortic balloon pump perioperatively. In addition, magnesium was superior to lidocaine, although both are effective.