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Unique Identifier 97152160
Authors: Schreck DM. Rivera AR. Tricarico VJ.
Institution: Department of Emergency Medicine, Muhlenberg Regional Medical Center, Plainfield, New Jersey, USA.
Title: Emergency management of atrial fibrillation and flutter: intravenous diltiazem versus intravenous digoxin.
Source: Annals of Emergency Medicine. 29(1)135-40, 1997 Jan. [see comments].
Abstract: STUDY OBJECTIVE: To compare the effects of i.v. diltiazem and i.v. digoxin on ventricular rate control in the emergency treatment of acute atrial fibrillation and flutter (AFF). METHODS: This prospective, randomized, open-label trial involved 30 consecutive patients who presented with acute AFF to the emergency department of an urban, 420-bed community teaching hospital from April 1993 through March 1994. Exclusion criteria included systolic blood pressure lower than 100 mm Hg, treatment with calcium-channel blockers other than diltiazem, lack of informed consent, and objection of the private physician. Patients were randomly assigned to receive either i.v. diltiazem alone, i.v. digoxin alone, or both. Heart rate control was defined as a ventricular rate of less than 100 beats/minute. I.v. digoxin, 25 mg, was given as a bolus at time 0 and 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 i.v. infusion at a rate of 10 to 20 mg/hour to maintain heart rate control. The dosing regimens were the same whether the drugs were given alone or in combination. Heart rhythm, heart rate, and blood pressure were measured at time 0, 5, 10, 15, 30, 60, 120, and 180 minutes. Statistical significance was assessed 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 the diltiazem group and 144 +/- 12 in the digoxin group (difference not significant, P = .432). The decrease in heart rate from time 0 reached statistical significance at time 5 minutes in the diltiazem group (P = .0006); the mean rates at time 5 minutes were 111 +/- 26 beats/minute for diltiazem and 144 +/- 13 for digoxin. The decrease in heart rate achieved with digoxin did not reach statistical significance until time 180 minutes (P = .0099), at which time the rates were 90 +/- 13 for diltiazem and 117 +/- 22 for digoxin. CONCLUSION: Treatment of acute AFF with i.v. diltiazem decreases ventricular heart rate significantly within 5 minutes, compared with 3 hours for treatment with i.v. digoxin. No advantage was noted within 3 hours for i.v. treatment with a combination of diltiazem and digoxin. I.v. diltiazem is superior to i.v. 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 to adequately assess adverse effects, and further studies may be warranted for clinical validation.

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Unique Identifier 95023333
Authors: Gonzalez ER. Ornato JP. Lawson CL.
Institution: Department of Pharmacy and Pharmaceutics, Medical College of Virginia, Richmond 23298.
Title: Clinical decision analysis modeling: short-term control of ventricular response rate in atrial fibrillation or atrial flutter-digoxin versus diltiazem.
Source: Pharmacotherapy. 14(4)446-51, 1994 Jul-Aug.
Abstract: OBJECTIVE. To develop a clinical decision model to compare the outcome of therapy with digoxin versus diltiazem for short-term control of ventricular response rate (VRR) in patients with atrial fibrillation or atrial flutter. DESIGN. Review of data from two studies that examined the percentages of response and frequency of adverse reactions in patients treated with intravenous digoxin or diltiazem to control VRR in atrial fibrillation or flutter. We constructed a clinical decision model and performed sensitivity analysis to determine if the model's predictions could be altered. SETTING. Large teaching, university hospitals. PARTICIPANTS. Adults age 18 years or older treated with intravenous digoxin or intravenous diltiazem for atrial fibrillation or flutter (VRR > or = 120 beats/min). Patients with severe heart failure New York Heart Association class III or IV, a surgical procedure prior to the exacerbation, or an acute myocardial infarction were excluded. MEASUREMENTS AND MAIN RESULTS. We measured VRR control after 1 and 24 hours of therapy (VRR < 100 beats/min or decrease of > or = 20%) and assessed the likelihood that a patient would suffer an adverse drug reaction. Initial assumptions were that the probability digoxin would achieve VRR control was 0.10 (95% confidence interval 0.04-0.20) at 1 hour and 0.70 (95% CI 0.56-0.80) at 24 hours; the probability that diltiazem would achieve VRR control was 0.94 (95% CI 0.82-0.99) at 1 hour and 0.83 (95% CI 0.68-0.94) at 24 hours; and the probability of no serious adverse drug reaction would be 0.90 (95% CI 0.80-0.96) for digoxin and 0.96 (95% CI 0.86-0.98) for diltiazem. RESULTS. Diltiazem was superior to digoxin with respect to the composite end point score at 1 hour (91.20 vs 17.29) and 24 hours (81.65 vs 66.43). Digoxin was superior to diltiazem at 24 hours only if the VRR was assumed to be at the highest 95% CI limit for digoxin and simultaneously at the lowest 95% CI for diltiazem (74.62 vs 68.63). CONCLUSIONS. Clinical decision analysis suggests that intravenous diltiazem is superior to intravenous digoxin in controlling VRR in patients with atrial fibrillation or flutter.

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Unique Identifier 89005166
Authors: Lewis RV. Irvine N. McDevitt DG.
Institution: Department of Pharmacology and Clinical Pharmacology, Ninewells Hospital and Medical School, Dundee, Scotland.
Title: Relationships between heart rate, exercise tolerance and cardiac output in atrial fibrillation: the effects of treatment with digoxin, verapamil and diltiazem.
Source: European Heart Journal. 9(7)777-81, 1988 Jul.
Abstract: Six patients with chronic atrial fibrillation (AF) took single doses of digoxin, verapamil and diltiazem, alone and in combination. Three hours after dosing, resting and post-exercise heart rate, exercise tolerance and resting and post-exercise cardiac output were measured. Post-exercise heart rates ranged from 167 bpm (after placebo) to 122 bpm (after digoxin plus diltiazem) (P less than 0.05). However, the lower ventricular rates seen after treatment with the calcium antagonists were not associated with improved exercise tolerance, which did not differ significantly between the various treatments. Reduction of the ventricular rate was associated with a small increase in stroke volume but the benefits of this were offset by a rate related reduction in cardiac output. Further reduction of the rapid ventricular rates seen in digitalized patients with AF does not appear to be of benefit in terms of improving either exercise tolerance or cardiac output.

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