Novel Electrocardiographic Parameters of Altered Repolarization in Uncomplicated Overweight and Obesity

Abstract

IntroductIonAn excessive caloric intake and a low physical activity have as consequence the development of obesity, which, in turn, may lead to an increased risk of cardiovascular morbidity and mortality (1,2). In obese subjects, compared to normal weight subjects, it has been shown a lengthening of corrected QT (QTc) and QT dispersion (QTd) (3,4), parameters related to an increased incidence of ventricular tachyarrhythmias in various pathologies (5-10).Interest has grown, recently, in new electrocardiographic parameters, as indirect indexes of ventricular repolarization; in particular the Tpeak-Tend (Tpe) interval, its dispersion (Tpe-d), and the relationship between Tpe interval and QT interval (Tpe/QT ratio) showed to be valid markers of arrhythmic vulnerability in coronary heart disease, in Brugada syndrome, in hypertrophic cardiomyopathy, and in long QT syndrome (11)(12)(13)(14)(15).The aforementioned parameters have not yet been evaluated in overweight/obese subjects. The aim of this study was to verify their potential alteration in obesity without associated comorbid conditions. Methods and ProceduresA total of 120 subjects were studied, divided into two groups. The first group was composed of 60 healthy, athletic subjects with normal weight (BMI ≤24.9 kg/m 2 ). They worked out at the gym three times a week for more than 60 min, engaging in aerobic and anerobic activities. The second group was composed of 60 sedentary, overweight (BMI between 25 and 29.9 kg/m 2 ) and obese subjects (BMI ≥30 kg/m 2 ). The first group comprised 21 women and 39 men with the following characteristics: BMI between 19 and 24 kg/m 2 , mean BMI 22.0 ± 2.0 kg/m 2 , aged 14-64 years, mean age 32 ± 13.59 years. The second group comprised 22 women and 38 men, 34 overweight and 26 obese subjects with the following characteristics: BMI between 26 and 55 kg/m 2 , mean BMI 30.7 ± 5.7 kg/m 2 , aged 14-64 years, mean age 38 ± 14.49 years. The subjects with a normal weight were recruited from the Division of Sports Medicine at Palermo University Hospital, the overweight and obese subjects came from a primary prevention ambulatory clinic. Nobody had a personal history of heart disease, hypertension, impaired glucose tolerance, diabetes, renal failure, hepatic or thyroid diseases. No one had a family history of long QT syndrome, electrolyte disorders

Body fat, especially visceral fat, is associated with electrocardiographic measures of sympathetic activation

“…We were able to extend these observations by showing that VAT was also associated with measures of sympathetic activation on the ECG (HR, QTc, and the ventricular gradient) after adjustment for SAT, while the association of SAT with these measures attenuated after adjustment for VAT. Finally, in line with our results, a recent paper observed an association of BMI with QTc, but not with Tpeak-end (35). We showed the same results for other body fat measures.…”

Age- and sex-based reference ranges for non-invasive ventricular repolarisation parameters

“…Moreover, repolarisation markers have been studied in athletes and in non-morbidly obese populations. [26][27][28][29][30] A relationship between Tpe duration and pacing-induced ventricular arrhythmia vulnerability has been demonstrated during electrophysiological study, 31 and data on large cohorts of patients have confirmed its utility as a risk stratification marker for sudden cardiac death and all-cause and cardiovascular mortality. 32,33 It is consequently essential to discriminate between normal and abnormal values in clinical decision-making.…”

“…Moreover, repolarisation markers have been studied in athletes and in non‐morbidly obese populations …”

Influence of long-term oral application of quinolones on the ECG curve in dogs

“…Barbhaiya et al (2013) concluded that both parameters are very useful in assessing the risk of ventricular arrhythmias in patients who underwent resynchronising therapy (Antzelevitch 2008). There are also studies proving the usefulness of these parameters in patients with the Burgada syndrome (Kay et al 1983, Braschi et al 2011. In veterinary medicine, there are isolated reports of the use of these markers and further studies are necessary to confirm their usefulness (Moss 1999).…”