Dzikowicz DJ, et al. - Researchers focused on the links between obesity, hypertension, and the interaction between them on QRS duration (QRSd) in this secondary data analysis including firefighters (n=77) with 89.4% being overweight or obese. The participants had no documented cardiovascular disease in normal sinus rhythm. Mean QRSd was measured by means of twelve-lead 24-hr electrocardiogram Holter monitors. They also measured and classified body mass index (BMI) and resting blood pressure (BP). Findings revealed an independent association of increased BMI and an interaction between BMI and systolic BP, with prolongation of the QRS complex.