Administration of Amiodarone into the Aortic Root for Persistent Ventricular Fibrillation After Aortic Valve Replacement

The effect of lidocaine and amiodarone on prevention of ventricular fibrillation in patients undergoing coronary artery bypass grafting

OBJECTIVE

Ventricular fibrillation is common after aortic declamping in patients undergoing open heart surgery. This situation has a negative impact on morbidity and mortality. The aim of this prospective study was to compare the effect of administering lidocaine versus amiodarone before aortic declamping during elective coronary bypass grafting, paying close attention to when the initial effect of amiodarone sets in.

METHODS

In this double blind, prospective, randomized, controlled study, 86 patients who were candidates for elective coronary artery bypass grafting were recruited into three groups: group lidocaine (group L, n=29); group amiodarone (group A, n=27); and group placebo (group P, n=30). Group L patients received 1.5 mg/kg of lidocaine 2 minutes before aortic declamping and group A patients received 300 mg of amiodarone intravenously 15 minutes before release of the aortic cross clamp. The primary endpoints were the incidence of ventricular fibrillation and the number of shocks required to terminate ventricular fibrillation.

RESULTS

The frequency of ventricular fibrillation occurrence was significantly higher in group P (70%) when compared with group A (37%) and group L (38%) (P=.017). There was no statistically significant difference between the amiodarone and the lidocaine groups regarding ventricular fibrillation. However, when ventricular fibrillation occurred, the percentage of patients requiring electrical defibrillation was significantly higher in both group L and group P when compared with group A (P=.023).

CONCLUSION

We suggest that during coronary arterial bypass surgery, administration of an amiodarone regime before release of the aortic cross clamp, paying particular attention to the start of the initial effect of amiodarone, is no more effective than lidocaine for prevention from arrhythmia; however, amiodarone reduces the need for electrical defibrillation.

Ventricular fibrillation with diminished internal mammary artery graft flow during sternal retraction

Ventricular fibrillation is a common arrhythmia encountered after the termination of cardiopulmonary bypass. Risk is augmented in patients who are undergoing repeat cardiac procedures with most documented complications occurring during repeat sternotomy. Aortic valve surgery is more complex after coronary artery bypass grafting using internal mammary arteries, and it compounds the increased risk of repeat sternotomy. This case report describes a low-flow state artificially created by sternal retraction applying tension on a right internal mammary artery to posterior descending artery anastomosis, with resultant unrecognized myocardial ischemia yielding refractory ventricular fibrillation during aortic valve replacement.