Case report of halofantrine induced QT interval prolongation with subsequent ventricular arrhythmias

ABSTRACT

A 45 years old lady, presented in emergency department of NICVD with 2 days history of high grade fever with rigors followed by severe vertigo. There was no previous history of any cardiac ailment nor she was hospitalized for any major illness. No family history of cardiac disease. No past history of palpitations or vertigo. She was prescribed antimalarial "halofantrine" in a dose of 500 mg 6 hourly [3 doses], a day prior to admission in NICVD. On examination, middle-aged lady appeared anxious and tachypnic. Apart from irregularly irregular pulse and relative hypotention rest of the examination was unremarkable. ECGInitial ECG showed prolongation of QT interval, i.e., 0.48 seconds. QTc, 0.6 seconds. She developed unstable Torsade De pointes and then subsequent ECGs showed recurrent intermittent ventricular tachycardia. Management Patient was cardioverted initially at 200 Joules, followed by i/v bolus of lignocaine; as she failed to respond, i/v magnesium sulphate was tried, as intermittent VT continued, temporary pacemaker was implanted and overdrive pacing successfully maintained normal sinus rhythm. Patient`s intrinsic heart rate was 80b/m, QT 0.48 sec. QTc, 0.6 see, while overdrive pacing was done at 120b/m, with QT 0.36 see, QTc 0.46 sec Investigations All routine hemotological and biochemical investigations were found normal including [CBC, ESR, RBS, Urea. Creatinene, Electrolytes, Cholesterol, UrineD/R, LFTs], Chest XRay and echocardiagraphy reports were also normal. Course in the HospitalSubsequently, temporary Pacemaker was switched off after few days. Serial ECGs showed normalization of QT interval. Last ECG showed QT of 0.4 seconds, QTc, 0.5 seconds. She was discharged after a week without any medication