Amiodarone versus diltiazem for rate control in critically ill patients with atrial tachyarrhythmias.
OBJECTIVE
To compare the rate-lowering effect of diltiazem and two amiodarone regimens in critically ill patients with recent-onset atrial tachyarrhythmias.


METHODS
Prospective, randomized, controlled study.


METHODS
Medical cardiologic intensive care unit in a university hospital.


METHODS
Sixty critically ill patients (Acute Physiology and Chronic Health Evaluation [APACHE] III score 70 +/- 30, age 67 +/- 10 yrs).


METHODS
Patients with atrial fibrillation (n = 57), atrial flutter (n = 2), or atrial tachycardia (n = 1, and a heart rate consistently >120 beats/min over 30 mins were randomly assigned to one of three intravenous treatment regimens. Group 1 received diltiazem in a 25-mg bolus followed by a continuous infusion of 20 mg/hr for 24 hrs, group 2 received amiodarone in a 300-mg bolus, and group 3 received amiodarone in a 300-mg bolus followed by 45 mg/hr for 24 hrs.


RESULTS
The primary study end point was a >30% rate reduction within 4 hrs. The secondary study end point was a heart rate <120 beats/min (a patient was considered to have uncontrolled tachycardia if heart rate was >120 beats/min 4 hrs after study drug). The primary study end point was achieved in 14/20 (70%), 11/20 (55%), and 15/20 (75%) of patients in groups 1, 2, and 3, respectively (chi2 = 1.95, p =.38). Uncontrolled tachycardia was more frequently observed in group 2 (0/20, 9/29 [55%], and 1/20 [5%] of patients in groups 1, 2, and 3, respectively; chi2 = 17, p =.00016). In patients achieving tachycardia control, diltiazem showed a significantly better rate reduction (p =.0001 group 1 vs. group 3, p =.0001 over time; p =.0001 group 1 vs. group 2, p =.001 over time) when compared with the amiodarone groups. Premature drug discontinuation due to hypotension was required significantly more often in group 1 (6/20 [30%], 0/20, and 1/20 [5%] for groups 1, 2, and 3, respectively; chi2 = 10, p =.01).


CONCLUSIONS
Sufficient rate control can be achieved in critically ill patients with atrial tachyarrhythmias using either diltiazem or amiodarone. Although diltiazem allowed for significantly better 24-hr heart rate control, this effect was offset by a significantly higher incidence of hypotension requiring discontinuation of the drug. Amiodarone may be an alternative in patients with severe hemodynamic compromise.
Delle Karth
G
G
Department of Cardiology, University of Vienna, Waeringer Gürtel 18-20, 1090 Vienna, Austria. georg.delle-karth@univie.ac.at
Geppert
A
A
Neunteufl
T
T
Priglinger
U
U
Haumer
M
M
Gschwandtner
M
M
Siostrzonek
P
P
Heinz
G
G
D018806:APACHE; D000368:Aged; D000638:Amiodarone / Q000008:administration & dosage / Q000627:therapeutic use*; D000704:Analysis of Variance; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D001282:Atrial Flutter / Q000188:drug therapy*; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D016638:Critical Illness; D004110:Diltiazem / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006339:Heart Rate; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D002121:Calcium Channel Blockers; D004110:Diltiazem; D000638:Amiodarone