Reduced cardiac reserve in amiodarone-treated pigs after cardiopulmonary bypass and cardioplegic arrest.
An animal model was designed for blinded study to elucidate whether cardiac pump failure after heart surgery in amiodarone-treated patients is due to interference between the drug and the surgical procedures. Seventeen adult pigs were treated with amiodarone for 30 days (study animals, 1,400 mg/day, n = 9; untreated control animals, n = 8) followed by exposure to cardiopulmonary bypass and topical cold cardioplegic arrest (Bretschneiders solution) for 60 min. Apart from 1 g of calcium, no inotropic agents were administered. Cardiac reserve was tested by ventricular pacing (200 beats/min for 30 min or until exhaustion). No difference in hemodynamic status was observed between the treated and the untreated group before pacing. Pacing duration in the amiodarone-treated pigs was 10 +/- 3 versus 22 +/- 4 min in control pigs (p less than 0.05). Only one amiodarone-treated pig survived 30 min of pacing compared with five control pigs (11% vs. 63%, p less than 0.05). The following variables differed significantly in the two groups during pacing: cardiac output, left ventricular pressure, arterial pressure and peak positive and negative first derivative of left ventricular pressure (dP/dt). Most marked were the changes in peak positive dP/dt, indicating a compromised systolic function. The two groups did not differ in preload or afterload at any time during the experiments.
Gøtzsche
L B
LB
Institute of Experimental Clinical Research, Skejby University Hospital, Aarhus, Denmark.
Pedersen
E M
EM
Keld
D
D
Paulsen
P K
PK
D000638:Amiodarone / Q000009:adverse effects* / Q000493:pharmacokinetics; D000818:Animals; D001682:Biological Availability; D002304:Cardiac Pacing, Artificial; D002315:Cardiopulmonary Bypass; D004195:Disease Models, Animal; D004311:Double-Blind Method; D006321:Heart / Q000187:drug effects*; D006324:Heart Arrest, Induced; D013552:Swine
D000638:Amiodarone