World Journal of
Pharmaceutical and Life Sciences

AN ELECTROCARDIOGRAPHIC ABNORMALITY IN OBESITY: A STUDY AT TERTIARY CARE HOSPITAL FROM CENTRAL INDIA

Premshanker Singh*, Ritu Karoli and Shobhit Shakya

ABSTRACT

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. The electrocardiogram of 515 obese subjects was correlated with the severity of obesity and with age, sex and blood pressure. The heart rate, PR interval, QRS duration, QTc interval and voltage (R + S or Q wave in leads I, II and III) increased and the QRS vector shifted to the left with increasing obesity. These changes were independent of age, sex and blood pressure. Bradycardia was present in 19% of the patients, but tachycardia in only 0.5%. ST and T wave abnormalities were present in 11%, correlating better with increasing age and blood pressure than with severity of obesity. This study evaluates the electrocardiogram in 515 patients with various degrees of obesity. The electrocardiographic measurements were related to the degree of obesity and the data were controlled for age, sex and blood pressure Most obese subjects with no clinical heart disease have a normal electrocardiogram. The heart rate increases with increasing obesity, but tachycardia is infrequent. ST segment and T wave abnormalities were present in approximately 11% of our patients, correlating better with increasing age and blood pressure than with degree of obesity. The PR interval and QRS duration increased with increasing obesity, but conduction abnormalities were very infrequent. The QTc interval was often prolonged in obese subjects and increased with increasing obesity. Low voltage was present in only 3.9% of the patients and QTc prolongation was present in 28.3%. The heart rate and QRS voltage increase with increasing obesity. Conduction is slowed, and the QRS vector shifts toward the left as percent overweight increases. These changes must be considered when evaluating both baseline electrocardiographic studies in obese patients and the changes seen during weight reduction.

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