Professional and Linguistic Assessments Board (PLAB) Practice Exam

What condition is characterized by Polymorphic ventricular tachycardia, commonly known as Torsades de Pointes?

1. Left dominant heart

2. Right dominant circulation

3. Ventricular fibrillation

4. Supraventricular tachycardia

The correct answer is: Left dominant heart

Torsades de Pointes is a specific type of polymorphic ventricular tachycardia that occurs in the setting of prolonged QT interval, whether congenital or acquired. It's characterized by a distinctive pattern on the electrocardiogram, where the peaks and troughs of the QRS complexes appear to rotate around the baseline. When considering the context of left dominant heart structures, it is important to note that the anatomy of the heart and its vascular supply can influence the types of arrhythmias that arise. A left dominant coronary system typically means that the left coronary artery supplies the majority of the heart, while a right dominant system places more reliance on the right coronary artery. In some cases, the specific architecture of the heart can predispose individuals to develop certain arrhythmias due to variations in myocardial perfusion and electrical conduction pathways. The other options, such as right dominant circulation, ventricular fibrillation, and supraventricular tachycardia, refer to different anatomical and pathological conditions not directly associated with Torsades de Pointes. Right dominant circulation refers to the blood supply structure of the heart, while ventricular fibrillation is a disorganized electrical activity of the ventricles leading to no effective heart contractions. Supraventricular tachycardia