Chloroquine

Abstract

QT interval prolongation: case report A 72-year-old woman developed QT interval prolongation during an off label treatment with chloroquine for COVID-19 viral pneumonia. The woman presented to the emergency department with fever and dyspnoea. Her medical history was significant for paroxysmal atrial fibrillation, for which she had been taking flecainide. At the time of presentation, she was tachypnoeic, her oxygen saturation was 92% and auscultation of the lungs showed bilateral inspiratory crackles and expiratory rhonchi. An ECG revealed sinus rhythm with normal repolarization and a normal QTc interval. She was suspected to have COVID-19 viral pneumonia. Hence, she was admitted to the pulmonology department and started receiving off label treatment with chloroquine 300mg once daily and cefuroxime 1500mg three times daily along with oxygen. Initially, two COVID-19 polymerase chain reaction (PCR) assays were negative. However, 5 days after the admission, she developed respiratory insufficiency and was admitted to the ICU, where mechanical ventilation was initiated. Eventually, COVID-19 infection was confirmed by PCR. She also developed hypotension secondary to deep sedation, which was successfully treated with low doses of norepinephrine. Seven days after the ICU admission, negative T-waves were seen at the monitor and a 12-lead ECG revealed sinus rhythm with diffuse, new, deeply negative T-waves and a prolonged QTc interval of 505ms [duration of treatment to reaction onset not stated]. Echocardiography revealed a poor left ventricular systolic function (left ventricular ejection fraction (LVEF) approximately 30%) with circumferential akinesia of the apex in the mid-ventricular and apical segments and circumferential hyperdynamic contractions of the basal segments consistent with the diagnosis of Takotsubo cardiomyopathy. Her Inter TAK Diagnostic Score was 80 supporting the diagnosis Takotsubo cardiomyopathy. In view of the poor left ventricular systolic function and prior atrial fibrillation, the woman was treated with dalteparin-sodium [dalteparin]. The woman’s chloroquine therapy was discontinued due to the prolonged QTc interval [outcome not stated]. After 10 days of mechanical ventilation, she was successfully extubated and transferred to the ward. Seven days after the diagnosis of Takotsubo cardiomyopathy, her troponin levels normalised. At that time, the ECG revealed sinus rhythm and normalisation of the Twaves. She was started on perindopril 2mg once daily but discontinued shortly because of symptomatic hypotension. Follow-up echocardiography reveled important improvement of left ventricular systolic function to an LVEF of 45%; however, hypokinesia of theapical segments persistent. Coronary computed tomography angiography (CCTA) revealed a low calcium score and a nonsignificant stenosis (<50%) in the proximal left anterior descending artery (CAD-RADS score of 1) and systolic function (LVEF 55%), as expected in Takotsubo cardiomyopathy.