My approach to the patient with a borderline long QT interval

A prolonged QT interval is typically defined in adults as a corrected QT interval exceeding 440 ms in males and 460 ms in females on resting electrocardiogram (ECG). We worry about QT prolongation because it reflects delayed myocardial repolarization, which can lead to torsades de pointes (TdP). Up to 50% of genetically affected LQTS patients actually have a normal or borderline resting QT interval, yet are still at risk for TdP, leading to syncope, cardiac arrest, or sudden death. As such, a borderline QT interval, for example, in a young, asymptomatic female undergoing routine ECG, poses a unique challenge.
Source: Trends in Cardiovascular Medicine - Category: Cardiology Authors: Source Type: research