minimum heart rate to qualify for Torsades de pointes

Q: By definition, what should be the minimum heart rate to qualify for Polymorphic Ventricular Tachycardia (Torsades de pointes) in adults?

Answer: 100 beats per minute

Polymorphic ventricular tachycardia, popularly known as Torsades de pointes ("twisting of the points.") is defined as a ventricular rhythm faster than 100 beats per minute in adults with frequent variations of the QRS axis, morphology, or both. Although minimum heart rate required is 100 beats per minute, usually heart rate runs between 160 to 250 beats per minute.

#cardiology

References:

1. Passman R, Kadish A. Polymorphic ventricular tachycardia, long Q-T syndrome, and torsades de pointes. Med Clin North Am 2001; 85:321.

2. Khan IA. Long QT syndrome: diagnosis and management. Am Heart J 2002; 143:7.

3. El-Sherif N, Turitto G. Torsade de pointes. Curr Opin Cardiol 2003; 18:6.