Conversion of postischemic ventricular fibrillation with intraaortic infusion of potassium chloride

Ventricular fibrillation after declamping of the aorta after cardioplegic arrest is commonly managed by direct-current countershock. However, in coronary artery bypass grafting, placement of the electrodes can cause mechanical damage to the grafts and anastomoses, and the surgical procedure must be interrupted. As an alternative, intraaortic infusion of potassium chloride through the arterial line from the heart-lung machine was investigated.

In a series of 100 patients with postischemic ventricular fibrillation (group P), 20 mmol of potassium chloride (plus 10 mmol later if necessary) was added to the oxygenator reservoir and perfused through the arterial line into the proximal aorta. The results were compared with those in a matched control group of 100 patients primarily treated with direct-current countershock (group DC).

In group P, the ventricular fibrillation was effectively converted to a supraventricular rhythm in 82% of the patients. The remaining 18 patients required significantly (p < 0.005) fewer electric shocks than the patients in group DC. Serum K+ levels were slightly elevated for a short period after the potassium chloride infusion. Otherwise there were no significant differences in regard to incidence of heart block, temporary epicardial pacing, myocardial infarction, or atrial fibrillation between the two groups.

Conversion of postischemic ventricular fibrillation with potassium chloride administered through the arterial line from the heart-lung machine is an effective, gentle, and convenient method. No side effects were noted.