EMERGENCY MANAGEMENT OF ATRIAL-FIBRILLATION AND FLUTTER - INTRAVENOUSDILTIAZEM VERSUS INTRAVENOUS DIGOXIN

Study objective: To compare the effects of IV diltiazem and IV digoxin on ventricular rate control in the emergency treatment of acute atria l fibrillation and flutter (AFF). Methods: This prospective, randomize d, open-label trial involved 30 consecutive patients who presented wit h acute AFF to the emergency department of an urban, 420-bed community teaching hospital from April 1993 through March 1994. Exclusion crite ria included systolic blood pressure lower than 100 mm Hg, treatment w ith calcium-channel blockers other than diltiazem, lack of informed co nsent, and objection of the private physician. Patients were randomly assigned to receive either IV diltiazem alone, IV digoxin alone, or bo th. Heart rate control was defined as a ventricular rate of less than 100 beats/minute. IV digoxin,.25 mg, was given as a bolus at time 0 an d at time 30 minutes. An initial dose of .25 mg/kg diltiazem was given intravenously over the first 2 minutes, followed by a dose of .35 mg/ kg at time 15 minutes and then a titratable IV infusion at a rate of 1 0 to 20 mg/hour to maintain heart rate control. The dosing regimens we re the same whether the drugs were given alone or in combination. Hear t rhythm, heart rate, and blood pressure were measured at times 0, 5, 10, 15, 30, 60, 120, and 180 minutes. Statistical significance was ass essed with the use of Student's t test and ANOVA methodology. Results: At time 0, the heart rate (mean+/-SD) was 150+/-19 beats/minute in th e diltiazem group and 144+/-112 in the digoxin group (difference not s ignificant, P=.432). The decrease in heart rate from time 0 reached st atistical significance at time 5 minutes in the diltiazem group (P=.00 06); the mean rates at time 5 minutes were 111+/-26 beats/minute for d iltiazem and 144+/-13 for digoxin. The decrease in heart rate achieved with digoxin did not reach statistical significance until time 180 mi nutes (P=.0099), at which time the rates were 90+/-13 for diltiazem an d 117+/-22 for digoxin. Conclusion: Treatment of acute AFF with IV dil tiazem decreases ventricular heart rate significantly within 5 minutes , compared with 3 hours for treatment with IV digoxin. No advantage wa s noted within 3 hours for IV treatment with a combination of diltiaze m and digoxin. IV diltiazem is superior to IV digoxin in the emergency control of ventricular rate in acute AFF and should be considered as a drug of choice for this condition. This study was not large enough t o adequately assess adverse effects, and further studies may be warran ted for clinical validation.