The Annals of Thoracic Surgery, Vol 39, 324-328, Copyright © 1985 by The Society of Thoracic Surgeons
Verapamil potassium cardioplegia and cardiac conduction
GL Hicks Jr and JA DeWeese
This clinical study analyzes the effect of potassium cardioplegic solution
containing verapamil hydrochloride (1 mg/L) on cardiac conduction after
release of the aortic cross-clamp and throughout recovery. Fifty
consecutive patients undergoing open-heart operation were studied as a unit
for postoperative conduction abnormalities. They were also analyzed in
groups based on spontaneous ventricular conversion to regular rhythm (54%)
and the need for single DC cardioversion (32%), or multiple DC
cardioversions (14%). Results showed that spontaneous ventricular
conversion had no relationship to aortic cross-clamp time and that DC
cardioversion using 10 Ws had no detrimental effects on the myocardium or
incidence of conduction abnormalities. The need for transient
intraoperative pacing was lowest with spontaneous ventricular conversion,
but not statistically different from single or multiple DC cardioversions.
Only 3 patients (6%) required pacing in the intensive care unit. The
incidence of postoperative atrial and ventricular arrhythmias was similar
in all groups, and no deaths or episodes of malignant ventricular
arrhythmias occurred. This study concludes that verapamil potassium
cardioplegia is associated with excellent myocardial protection and a high
incidence of transient intraoperative dysfunction of the atrioventricular
node (70%) but a low incidence of postoperative pacing. Benign
postoperative arrhythmias occur, but at hospital discharge, few conduction
abnormalities (10%) persist.