Multiple drugs

Abstract

Wide complex tachycardia followed by lack of efficacy: case report A female neonate [exact age at onset not stated] exhibited lack of efficacy during treatment with adenosine, propranolol, amiodarone and digoxin for automatic atrial tachycardia. Subsequently, she developed wide complex tachycardia during treatment with sotalol [not all routes and dosages stated]. The girl child was born at 35 weeks + 2 days of gestational age by vaginal delivery due to pre-eclampsia, with a body weight at birth of 2450g. An ECG confirmed sinus rhythm and an echocardiogram showed a good biventricular function and absence of congenital heart disease. She had no family history of any structural and arrhythmic cardiac diseases. However, given the clinical history, flecainide was administered prophylactically at birth. At 5 days of life, after a crying episode, a narrow QRS complex tachycardia was detected at 210 bpm. Imaging study showed a prolonged PR interval. She was administered with adenosine 0.2 mg/kg, which temporarily slowed her heart rate, but a cardioversion was not achieved, even with the addition of propranolol [propanolol] at 2.5 mg/kg/day. Subsequently, flecainide and propanol were discontinued, and IV amiodarone loading dose of 5 mg/kg, followed by 10 mg/kg/day and oral digoxin 10 mcg/kg were initiated. At 10 days of life, she was admitted to a hospital in Italy. Digoxin was discontinued and amiodarone was increased up to 18 mg/kg/day (i.e., 13.3 mcg/kg/min) without obtaining cardioversion, but only adequate heart rate control up to 140 bpm. Afterwards, due to persistence of tachycardia, flecainide was recommenced at a higher dose, and IV amiodarone was discontinued in the following days. Blood levels of flecainide were periodically checked with blood tests. A period of prevalent sinus rhythm was achieved, however, due to relapses, the dose of flecainide was increased again. Sotalol was also added at 3 mg/kg/day (3 mg thrice a day) and then increased up to 6 mg/kg/day (6 mg thrice a day). At 29 days of life, a wide complex tachycardia developed secondary to sotalol, with a heart rate of 215-240 bpm, undetectable P waves, and with the help of a transesophageal electrophysiological study a ventricular tachycardia was excluded and the diagnosis of automatic atrial tachycardia (AAT) was confirmed. The girl’s treatment was switched from sotalol and flecainide to nadolol. In the following days, the infant represented with AAT, and flecainide was added to the treatment. During this combination therapy, episodes of SVT were noted to reappear just before the next administration of flecainide and they became progressively less frequent as increased the number of daily administrations. Eventually, there were no further recurrences when flecainide was administered at a constant dose. During the admission, she maintained appropriate weight gain, and was discharged home at 54 days of life, with flecainide, nadolol and ECG home monitoring. During her first follow-up visit (at 65 days of life), an ECG revealed a sinus rhythm with a heart rate of 122 bpm with good control of the arrhythmia. No further episodes of SVT were detected and no adverse effects were reported.