A RANDOMIZED, DOUBLE-BLIND COMPARISON OF INTRAVENOUS DILTIAZEM AND DIGOXIN FOR ATRIAL-FIBRILLATION AFTER CORONARY-ARTERY BYPASS-SURGERY

Background Atrial fibrillation (AF) after coronary bypass graft surger y may result in hypotension, heart failure symptoms, embolic complicat ions, and prolongation in length of hospital stay (LOHS). The purpose of this study was to determine whether intravenous diltiazem is more e ffective than digoxin for ventricular rate control in AF after coronar y artery bypass graft surgery. A secondary end point was to determine whether ventricular rate control with diltiazem reduces postoperative LOHS compared with digoxin. Methods and Results Patients with AF and v entricular rate >100 beats/min within 7 days after coronary artery byp ass graft surgery were randomly assigned to receive intravenous therap y with diltiazem (n = 20) or digoxin (n = 20). Efficacy was measured w ith ambulatory electrocardiography (Holter monitoring). Safety was ass essed by clinical monitoring and electrocardiographic recording. LOHS was measured from the day of surgery. Data were analyzed with the inte ntion-to-treat principle in all randomly assigned patients. In additio n, a separate intention-to-treat analysis was performed excluding pati ents who spontaneously converted to sinus rhythm. In the analysis of a ll randomly assigned patients, those who received diltiazem achieved v entricular rate control (greater than or equal to 20% decrease in pret reatment ventricular rate) in a mean of 10 +/- 20 (median 2) minutes c ompared with 352 +/- 312 (median 228) minutes for patients who receive d digoxin (p < 0.0001). At 2 hours, the proportion of patients who ach ieved rate control was significantly higher in patients treated with d iltiazem (75% vs 35%, p = 0.03). Similarly, at 6 hours, the response r ate associated with diltiazem was higher than that in the digoxin grou p (85% vs 45%, p = 0.02). However, response rates associated with dilt iazem and digoxin at 12 and 24 hours were not significantly different. At 24 hours, conversion to sinus rhythm had occurred in 11 of 20 (55% ) patients receiving diltiazem and 13 of 20 (65%) patients receiving d igoxin (p = 0.75). Results of the analysis of only those patients who remained in AF were similar to those presented above. There was no dif ference between the diltiazem-treated and digoxin-treated groups in po stoperative LOHS (8.6 +/- 2.2 vs 77 +/- 2.0 days, respectively, p = 0. 43). Conclusions Ventricular rate control occurs more rapidly with int ravenous diltiazem than digoxin in AF after coronary artery bypass gra ft surgery. However, 12- and 24-hour response rates and duration of po stoperative hospital stay associated with the two drugs are similar.