Q; Which gender tends to have a higher propensity to have a prolonged QT interval? (select one)
The 99th percentile of QTc value in an adult male has a QT interval on average of 470 milliseconds and an adult female of 480 milliseconds. This makes the female gender more prone to develop prolong QT-related arrhythmias. This also explains why females are more at risk of Torsades de Pointes (TdP) with sotalol and other commonly prescribed anti-arrhythmic drugs. Female sex is considered the highest risk factor for drug-induced TdP.
The objective of the above question is to highlight the American Heart Association/American College of Cardiology (AHA/ACC) scientific statement on the prevention of TdP in hospital settings that a QTc over the 99th percentile should be considered abnormally prolonged.
References:1. Drew BJ, Ackerman MJ, Funk M, et al. Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation. Circulation 2010; 121:1047.