A CASE OF A SURVIVOR OF AN OUT-OF HOSPITAL CARDIAC ARREST WITH A PROLONGED QTC INTERVAL PERHAPS DUE TO COMBINED PHARMACOTHERAPY OF BIPOLAR DISORDER TYPE II.

A thirty three year old man was brought to hospital after seventeen minutes of out-of-hospital cardiopulmonary resuscitation. The first recorded rhythm was ventricular fibrillation which was successfully terminated in the field. 

Upon arrival to hospital, an electrocardiogram showed sinus rhythm with a prolonged QTc interval and incomplete right bundle branch block. Transthoracic echocardiogram (TTE) demonstrated normal sized heart chambers, a moderately decreased left ventricular ejection fraction of 35-40 % and diffuse hypokinesis of the left ventricle. The patient’s past medical history was notable for bipolar disorder type II, requiring hospitalization ten weeks ago. He had been taking bupropion 150 mg p.o. per day and lamotrigine 200 mg p.o. per day since discharge from the psychiatric facility. Aminotriptyline 25 mg p.o. per day at night was administered during the stay at the same psychiatric facility to treat insomnia and had been discontinued upon discharge. At that time, his resting EKG had showed normal QTc interval. The prolonged QTc interval was serially followed and within 3 days normalized. No gabapentin or bupropion was given. The most plausible clinical explanation for the prolonged QTc interval would be lengthy resuscitation as suggested by entry TTE findings, entry lactate level of 7.2 mmol/L and pH of 7.18. 

Whilst considering possible effects of medication on cardiac arrest we found a report of intentional overdose with lamotrigine (7.95 grams p.o.) and bupropion (4 grams p.o.) leading to cardiac arrest (1) but apparently with excessive doses. There is also a suggested association between sudden cardiac deaths in patients with epilepsy taking lamotrigine in usual doses. The explanation could be a channelopathy leading to both epilepsy and a propensity to prolong QTc leading to malignant arrhythmia. (2).