Introduction

There is a worldwide epidemic of obesity in developed nations that involves virtually all ages, races and socio-economic classes. In the US alone nearly one-third of the population is overweight or obese. Consequently, it is logical to assume that a comparable proportion of patients presenting for anesthesia and analgesia will be overweight or obese, and will be subject to the complications of this increasingly common malady. A resting 12-lead electrocardiogram (ECG) is routinely performed on obese patients who present for medical or surgical evaluation. Obesity is associated with a wide variety of ECG abnormalities. Some of these are innocuous. Some may represent alterations in cardiac morphology associated with obesity and/or its co-morbidities. Still others may serve as markers of risk for sudden cardiac death. Many of these alterations are reversible with weight loss. This chapter describes ECG abnormalities associated with obesity. Morbidly obese patients receive special attention because of the large body of information available concerning the ECG in this group. In addition to reviewing alterations in heart rate, axis, waves and intervals, this chapter addresses the issue of arrhythmogenesis by discussing ventricular repolarization, the signal-averaged ECG and heart rate variability. Arrhythmias associated with obesity are also reviewed. Finally, ECG abnormalities and arrhythmias associated with dietary therapy, bariatric surgery and currently available anorexiant drugs are described.