Obesity is associated with a wide variety of electrocardiographic (ECG) abnormalities. Most of these reflect alterations in cardiac morphology. Some serve as markers of risk for sudden death. Key ECG abnormalities or alterations occurring with disproportionately high frequency in obese subjects include: leftward shifts of the P wave QRS and T wave axes, various changes in P wave morphology, low QRS voltage, various markers of left ventricular hypertrophy (particularly the Cornell voltage and product), T wave flattening in the inferior and lateral leads, lengthening of the corrected QT interval and prolonged QT interval duration. Alterations in the signal-averaged ECG and in heart rate variability may be arrhythmogenic. Cardiac arrhythmias have been described in obese subjects, but are often accompanied by left ventricular hypertrophy or the sleep apnea syndrome. Many of these ECG abnormalities are reversible with substantial weight loss. Thus, obesity is associated with a wide variety of ECG abnormalities, many of which are corrected by weight loss.

To assess the effect of obesity on blood pressure measurement the authors obtained simultaneous oscillometric and intraarterial systolic and diastolic blood pressures on 188 lean, overweight, class I/II obese, and class III obese subjects. Oscillometric arm cuff/bladder size was selected in accordance with standard guidelines. Oscillometry significantly underestimated systolic and significantly overestimated diastolic blood pressures in each of the 4 weight groups studied. The differences between oscillometric and intraarterial systolic and diastolic pressures were not significantly different among lean, overweight, class I/II obese, and class III obese subjects. Thus, obesity per se does not influence the accuracy of blood pressure measurement. However, oscillometric blood pressure measurement is associated with significant error when compared to intraarterial blood pressure.

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