Amiodarone attenuates the proarrhythmic effects of dobutamine in patients with advanced congestive heart failure.
BACKGROUND
The long-term use of positive inotropic pharmaceuticals in patients suffering from end-stage congestive heart failure (CHF) has been associated with increased mortality, presumed to be due to proarrhythmia. Oral amiodarone combined with intermittent dobutamine infusions (IDI), on the other hand, has been shown to increase survival. This study evaluated the effects of oral amiodarone on the arrhythmias caused by dobutamine in patients with advanced CHF.


METHODS
Thirty patients with CHF, in New York Heart Association functional class III or IV despite optimal medical therapy, were treated with weekly 8-h infusions of dobutamine 10 Ig/kg/min. All patients were treated for 1 month with oral amiodarone, 400 mg/day, before initiation of IDI. A 24-h ambulatory electrocardiogram was recorded on the day before dobutamine infusion and repeated the next day, starting with the onset of infusion.


RESULTS
The average heart rate on the 24-h ambulatory electrocardiogram was 72 +/- 14 beats/min before vs. 72 +/- 12 beats/min during IDI (p=1.000). Likewise, dobutamine did not increase the frequency of premature ventricular complexes (23 +/- 32 per h before vs. 42 +/- 69 per h during infusion, p=0.131), ventricular couplets (18 +/- 36 per 24 h vs. 17 +/- 28 per 24 h, p=0.859), or the incidence of non-sustained ventricular tachycardia (27% vs. 40%, p=0.383). No patient developed ventricular fibrillation or sustained ventricular tachycardia during or after IDI.


CONCLUSIONS
Chronic low-dose oral amiodarone attenuates the proarrhythmic effects of dobutamine, increasing the safety of ambulatory IDI.
Tsagalou
Eleftheria P
EP
3rd Cardiology Department, University of Athens School of Medicine, Athens, Greece.
Gounopoulos
Pantelis
P
Terrovitis
John V
JV
Drakos
Stavros G
SG
Katsaros
Fotios T
FT
Kaldara
Elisabeth E
EE
Alexopoulos
George P
GP
Anastasiou-Nana
Maria I
MI
D000284:Administration, Oral; D000638:Amiodarone / Q000008:administration & dosage*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage*; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D004280:Dobutamine / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D004280:Dobutamine; D000638:Amiodarone