Cardiology Drug References
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Innes GD, Vertesi L, Dillon EC, Metcalfe C
Effectiveness of verapamil-quinidine versus digoxin-quinidine in the emergency
department treatment of paroxysmal atrial fibrillation
Ann Emerg Med 1997; 29:126-34

STUDY OBJECTIVE: To determine the relative effectiveness of a
verapamil-quinidine sequential combination versus digoxin-quinidine in the
emergency department treatment of paroxysmal atrial fibrillation (PAF).
METHOD: This prospective, double-blind, randomized, controlled trial involved
patients, aged 18 to 75 years, with new-onset (< 48 hours) atrial fibrillation
who presented to a community-based urban hospital with an annual ED census of
65,000. Exclusion criteria included ventricular response rate lower than 100
or higher than 200 beats/minute, allergy to study drugs, hypotension with
evidence of end-organ hypoperfusion, and conduction abnormalities. Consenting
patients were randomly assigned to receive rapid digitalization (1.0 mg over 2
hours) or i.v. verapamil (sequential 5-mg boluses up to 20 mg). After
ventricular rate was controlled (< 100 beats/minute), oral quinidine (200 mg)
was initiated and repeated every 2 hours until conversion to normal sinus
rhythm (NSR) occurred, until 1 g of quinidine was administered, or until
adverse effects supervened. Heart rate, blood pressure, cardiac rhythm, time
to conversion, and adverse effects were documented. RESULTS: Forty-four
patients received the study drugs. Three were withdrawn, leaving 19 in the
verapamil-quinidine (VER-Q) group and 22 in the digoxin-quinidine (DIG-Q)
group. Sixteen patients (84%) in the VER-Q group and 10 (45%) in the DIG-Q
group converted to NSR within 6 hours (P < .02). Mean time to conversion
(+/-SD) was 185 +/- 146 minutes for VER-Q and 368 +/- 386 minutes for DIG-Q
patients (P = NS). Twelve VER-Q patients (63%) and 6 DIG-Q patients (27%) were
discharged from the ED (P < .05). Minor adverse effects were more common in
the VER-Q group. No mortality or significant morbidity occurred. CONCLUSION:
The sequential combination of verapamil and quinidine, in the doses studied,
is an effective treatment for PAF and is superior to digoxin-quinidine.
Digoxin should no longer be considered the treatment of choice for
uncomplicated PAF.

Schreck DM, Rivera AR, Tricarico VJ
Emergency management of atrial fibrillation and flutter: intravenous diltiazem
versus intravenous digoxin
Ann Emerg Med 1997; 29:135-40

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 times 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.