Name two inherited tachyarrhythmia syndromes associated with sudden cardiac death.

• A. Wolff-Parkinson-White syndrome and Long QT syndrome
• B. Sick sinus syndrome and Brugada syndrome
• C. Long QT syndrome and Brugada syndrome
• D. Catecholaminergic polymorphic VT and hypertrophic cardiomyopathy

Answer: (C)

The key idea is that some inherited heart rhythm disorders are channelopathies that disrupt how ions move in heart cells, creating a high risk of dangerous ventricular rhythms and sudden cardiac death even when the heart’s structure looks normal.

Long QT syndrome lengthens the cardiac repolarization, which shows up as a prolonged QT interval on the ECG. This creates a substrate for torsades de pointes, a dangerous form of a fast heart rhythm that can deteriorate into ventricular fibrillation and sudden death. Brugada syndrome, on the other hand, involves a distinct ECG pattern with ST-segment elevations in the right precordial leads and is linked to malignant ventricular arrhythmias, often occurring at rest or during sleep. Both are classic inherited channelopathies and are commonly discussed together as syndromes tied to sudden cardiac death.

Other options mix conditions that aren’t primarily tachyarrhythmia channelopathies or aren’t classically presented as inherited arrhythmia syndromes linked to sudden death (for example, sick sinus syndrome is mainly bradyarrhythmia; hypertrophic cardiomyopathy is structural heart disease).