Amiodarone/digoxin/esmolol
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Amiodarone/digoxin/esmolol Recurrent Torsades de pointes and lack of efficacy: case report
A 4-year-old boy developed recurrent Torsade de Pointes during treatment with amiodarone for ectopic atrial tachycardia. He also experienced lack of efficacy during treatment with amiodarone, digoxin and esmolol for ectopic atrial tachycardia [dosages not stated; not all routes stated]. The boy was brought to the emergency department due to prolonged abdominal pain and lethargy. On admission, his BP, pulse and respiratory rate were 96/56mm Hg, 208 beats/min and 40 breaths/min, respectively. His weight was 22kg, which had recently increased by 2kg. On chest x-ray, the cardiothoracic ratio was 62% and bilateral pleural effusions were present. Electrocardiography showed narrow QRS tachycardia with invisible normal P-waves. During atrioventricular conduction block by adenosine, ectopic Pwaves were apparent; therefore, ectopic atrial tachycardia was suspected. Echocardiography showed dilation of the four cardiac chambers and a left ventricular ejection fraction of 33%. The plasma level of B-type natriuretic peptide was 3296 pg/mL. Intravenous digoxin was initially started for rate control, but it was ineffective. A very low dose of esmolol was administered, but his BP decreased to 70/49mm Hg. Consequently, esmolol was discontinued. Intravenous amiodarone infusion was started for sustained atrial tachycardia; however, it remained uncontrolled. Subsequently, amiodarone was stopped due to recurrent Torsade de pointes and non-sustained ventricular tachycardia [duration of treatment to reaction onset not stated]. Since the atrial tachycardia could not be controlled with the antiarrhythmic drugs, electrophysiologic study and radiofrequency catheter ablation were planned. Temporary terminations of atrial tachycardia were achieved several times during the ablation, but the tachycardia frequently recurred at multiple sites in the left atrial appendage. Even after the radiofrequency catheter ablation, his pulse increased to 215 beats/min and his systolic BP decreased to 50mm Hg. Due to intractable atrial tachycardia and worsening heart failure, the boy underwent atrial appendectomy using a video-assisted thoracoscopic approach. Immediately after the appendectomy, the persistent atrial tachycardia was resolved, and his rhythm restored to sinus rhythm while in the operating room. The surgery was uneventful, and he was extubated the day after the surgery. His left ventricular ejection fraction increased to 60% within 1 week and he was discharged. His cardiothoracic ratio on chest x-ray decreased to 47%, and plasma B-type natriuretic peptide level decreased to 31 pg/mL within 2 months. He had no arrhythmia and maintained normal left ventricular function during the subsequent 9-month follow-up period. Pathologic evaluation of the left atrial appendage showed multiple round lesions, caused by the radiofrequency catheter ablations, and intervening non-ablative myocardium. The ablative lesions showed acute myocardial coagulative necrosis, hae
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