Effects of diltiazem versus digoxin on dysrhythmias and cardiac function after pneumonectomy

This prospective study was designed to determine whether diltiazem is superior to digoxin for the prophylaxis of supraventricular dysrhythmias (SVD) after pneumonectomy or extrapleural pneumonectomy (EPP) and to assess the influence of these drugs on perioperative cardiac function.

Seventy consecutive patients without previous SVD were randomly allocated immediately after pneumonectomy or EPP to receive diltiazem (n = 35) or digoxin (n = 35). Diltiazem-treated patients received a slow intravenous loading dose of 20 mg, followed by 10 mg intravenously every 4 hours for 24 to 36 hours, then 180 to 240 mg orally daily for 1 month. Digoxin-treated patients received a 1-mg intravenous loading in the first 24 to 36 hours, then 0.125 to 0.25 mg orally daily for 1 month. A concurrent prospective cohort of 40 patients without previous SVD, who did not participate in the study and underwent pneumonectomy or EPP without prophylaxis, served as a comparison group for SVD occurrence. Serial Doppler echocardiograms were performed to assess cardiac function and all patients were continuously monitored with Holter recorders for 3 days. Data were analyzed by intent-to-treat.

In patients undergoing standard or intrapericardial pneumonectomy, diltiazem prevented the overall incidence of postoperative SVD when compared with digoxin, 0 of 21 patients versus 8 of 25 patients, respectively, p < 0.005. When EPP patients were included in the analysis, diltiazem decreased the incidence of all SVD from 11 of 35 patients (31%) to 5 of 35 patients (14%) when compared with digoxin, p = 0.09. Digoxin-treated patients had a similar incidence of all SVD (31%) as concurrent controls (11 of 40 patients [28%]). The two treated groups did not differ in right or left atrial size, left ventricular ejection fraction, or right heart pressure. When all patients were combined, those in whom SVD developed were significantly older (65 +/- 12 years versus 55 +/- 11 years, p = 0.004) and had a longer median hospital stay (9 versus 6 days, p = 0.03), when compared with those in whom SVD did not develop, respectively. The subset of patients undergoing EPP had a greater incidence of atrial fibrillation and electrocardiographic changes suggestive of postoperative pericarditis than all other pneumonectomy patients.

Diltiazem was both safe and more effective than digoxin in reducing the overall incidence of SVD after standard or intrapericardial pneumonectomy. Digoxin therapy had no effect on the incidence of postoperative SVD and is not recommended for prophylaxis of SVD. Dysrhythmias after pneumonectomy or EPP occur in older patients and are associated with a greater length of hospital stay.