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].