Effect of Weight Loss on the ECG of Normotensive Morbidly Obese Patients

Abstract

Morbid obesity produces a variety of ECG alterations, including leftward shifts of the P-wave, QRS, and T-wave axes; disproportionately high frequencies of low QRS voltage; left ventricular hypertrophy and left atrial abnormality; and a high frequency of T-wave flattening in the inferior and lateral leads. This study was designed to assess the effects of substantial weight loss on the ECG in morbid obesity. We performed a resting 12-lead ECG on 60 normotensive patients (48 women and 12 men; mean +/- SD age, 37 +/- 7 years), whose body weight was twice their ideal body weight prior to and at the time of maximum weight loss after bariatric surgery. Mean weight decreased from 136 +/- 7 to 85 +/- 3 kg. Weight loss produced significant decreases in the frequencies of low QRS voltage; Romhilt-Estes point score > or = 5 points; SV(1) + RV(5) or V(6) > 35 mm; RV(5) or V(6) > 26 mm; RaVL > 11 mm; RaVL > or = 7.5 mm; SaVR > 14 mm; P-terminal force more negative than - 0.04 mm.s in lead V(1); and T-wave flattening in the inferior, lateral, and inferolateral leads. Weight loss significantly shifted the mean P-wave, QRS, T-wave axes rightward, and significantly reduced mean RaVL and mean SaVR voltage. Substantial weight loss is capable of reversing many of the ECG alterations associated with morbid obesity.