Case description
A 49-year-old male with past medical history of alcoholic liver cirrhosis was admitted to the emergency room in hemorrhagic shock due to bleeding from esophageal varices, resolved by endoscopic treatment. Later, he developed atrial fibrillation and intravenous amiodarone was initiated. After that, he presented non-sustained polymorphic ventricular tachycardia. The electrocardiogram showed flattened T waves and slightly prolonged corrected QT interval (QTc) that was not noticed (Figure 1A). Magnesium sulphate and amiodarone (total dose of 2100 mg in 36 hours) were administered to prevent ventricular dysrhythmia. Then, he developed recurrent sustained polymorphic ventricular tachycardia requiring defibrillation several times. The electrocardiogram revealed QTc higher than 700 milliseconds and T-wave alternans (Figure 1B). It was assumed iatrogenic QTc prolongation due to concomitant use of amiodarone plus tiapride. Isoproterenol with target heart rate of 100 beats per minute was initiated. Ventricular dysrhythmia terminated and QTc progressively normalized (Figure 1C).
Amiodarone is commonly used in acute care due to its effectiveness in several arrythmias and safety if structural heart disease is present or unknown [1]. However, it has proarrhythmic risk, especially in the presence of other conditions that prolong the QT interval [1]. Isoproterenol is a less invasive alternative to the temporary overdrive pacing in preventing ventricular dysrhythmia [2].