“Torsade de Pointes” in Patients with Structural Heart Disease and Atrial Fibrillation Treated with Amiodarone, β‐Blockers, and Digitalis

Abstract

Amiodarone is one of the most efficient and safe antiarrhythmic drugs in the treatment of atrial fibrillation (AF). Yet, though rare, proarrhythmic effects remain a clinical problem. We present three cases of amiodarone-associated "Torsade de pointes" tachycardia (Tdp) in patients treated concomitantly with heart rate controlling medication for AF. Amiodarone loading therapy was started for the treatment of tachyarrhythmic AF in all the three patients. All presented with a history of coronary heart disease, resulting in a severely reduced left ventricular ejection fraction in two patients. One received oral amiodarone loading, in the others, amiodarone was administered intravenously because of hemodynamically relevant AF episodes. Amiodarone therapy was combined with a heart rate controlling medication including a beta-blocking agent and digitalis in all the cases. All the subjects suffered from clinically relevant Tdp in the early run after initiation of amiodarone loading (max. 48 hours). The mean QTc in all patients before induction of Tdp was prolonged. The present case reports imply that amiodarone in combination with beta-blocker/digitalis therapy may be associated with an elevated proarrhythmic risk in selected patients with structural heart disease and AF.

Estudio sobre los efectos adversos de los fármacos antiarrítmicos en pacientes con fibrilación auricular atendidos en un Centro de Atención Primaria

“…Se incluyó a 400 pacientes, 215 mujeres (53,75%), con una edad media (DE) de 75,8 (11,12) añ os. Las características clínicas de los pacientes incluidos se muestran en la tabla 1.…”

“…Tanto para una como para la otra se pueden utilizar distintos fá rmacos antiarrítmicos y/o té cnicas no farmacoló gicas, ademá s de la profilaxis tromboembó lica, que debe plantearse en todos los casos. Actualmente, los fá rmacos antiarrítmicos se utilizan con el fin de controlar la frecuencia ventricular, restablecer el ritmo sinusal y/o prevenir las recurrencias 8 , pero tienen una elevada tasa de efectos adversos (EA) [9][10][11][12][13][14] . Este hecho representa una de las mayores dificultades que encuentran los mé dicos que atienden a pacientes con FA a la hora de determinar el tratamiento antiarrítmico má s apropiado 15 .…”

“…Los primeros son poco frecuentes pero tienen una alta morbimortalidad. Los principales son la bradicardia sinusal, el alargamiento del segmento QT, la taquicardia ventricular polimó rfica tipo «Torsades de Pointes» y un aumento del riesgo de algunas taquicardias ventriculares 10,11 . Los EA no arritmogé nicos má s frecuentes son la anorexia, ná useas, vó mitos, neuropatía perifé rica, temblor, hipo e hipertiroidismo, hipotensió n, broncoespasmo o fibrosis pulmonar 12,13 .…”

Amiodarone and digitalis: An odd couple in a tachycardiomyopathic patient

“…Proarrhythmic effects of amiodarone and digitalis combination have already been described in case series [4] and small observational studies [5] but no large clinical trial has tackled this important issue yet. Moreover, said evidence is mainly related to ischemic cardiomyopathy and our case is the first to report similar proarrhythmic events in acute left ventricular dysfunction due to a reversible tachycardiomyopathy, without any coronary disease.…”

“…The association between amiodarone and TdP may be promoted by concomitant electrolytes imbalance, high drug dosages, or left ventricular dysfunction [2,3] . Amiodarone and digitalis have already been described as an "odd couple", producing TdP and other ventricular arrhythmias, especially in chronic heart failure secondary to coronary heart disease [4,5] . Hereby, we are presenting the first case in which the proarrhythmic effect of this combination is evident in acute non-ischemic ventricular dysfunction.…”