Physical Activity, BMI and Smoking History Affect QT Interval Duration in Cardiac Patients

The QT interval is an element of the electrocardiograph (ECG) tracing that includes ventricular depolarization and repolarization and that provides clinical evidence regarding ventricular function. Long QT syndrome (LQTS) extends the relative refractory period of ventricular repolarization, thus placing the individual at risk for sudden cardiac death.

The purpose of the researchers by this study was to determine if QT interval duration was significantly different in cardiac patients based on modifiable risk factors such as smoking, physical activity (PA) and body mass index (BMI).

89 (48 males; 41 females; average age [yr) 59.4 ± 13.1; average BMI 29.75± 4.99) Materials/Methods: This study was a retrospective cohort study to determine if QT interval duration, corrected for heart rate (QTc), is significantly different based on PA, BMI, and cardiac medication intake while statistically controlling for smoking history in cardiac patients completing physical stress testing at a Midwestern hospital.

Clinical Relevance: This study supports the need for physical therapists (PTs) to be aware of each patient’s medical history when completing risk assessments for patients with non-communicable diseases such as heart disease, prior to engaging them in any therapeutic physical intervention and when prescribing activity and therapeutic exercise (APTA HOD P06-12-20-07; 2012).