The Relationship between Body Composition and ECG Ventricular Activity in Young Adults

This study aimed to determine the correlation between body composition (measured as weight, body mass index, and body fat percentage (BFP)) and electrocardiographic ventricular parameters (the QT and TQ intervals and the ratios between the electrical diastole and electrical systole (TQ/QT) and between the cardiac cycle and electrical diastole (RR/TQ), both for uncorrected and corrected intervals) in a sample of 50 healthy subjects (age interval 19-23 years, mean age 21.27 ± 1.41 years, 33 women and 17 men). Subjects' measurements were performed with a bioimpedancemetry body composition analyzer and a portable ECG monitor with six leads. Starting from the correlations obtained between the investigated continuous variables, we performed a standard linear regression analysis between the body composition parameters and the ECG ones. Our results revealed that some of our regression models are statistically significant (p < 0.001). Thus, a specific part of the variability of the dependent variables (ECG ventricular activity parameters for corrected QT intervals) is explained by the independent variable BFP. Therefore, body composition influences ventricular electrical activity in young adults, which implies a differentiated interpretation of the electrocardiogram in these situations.

Quantifying Long QT Syndrome in Obese Sleep Apnea Patients Undergoing Roux-en-Y Gastric Bypass Surgery

Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS) is sleep-disordered breathing distinguished by repetitive cessation or reduction of airflow due to the collapse or narrowing of the upper airway during sleep with continued respiratory effort. A high level of incidence of OSAHS is correlated with obesity. Both severely obese patients and OSAHS patients manifest Long QT Syndrome (LQTS). It is reported that most obese patients undergoing weight reduction surgery positively reverse symptoms of LQST. Also, severely obese OSAHS undergoing the same surgery report alleviation of OSAHS symptoms. In this study, we presented preliminary results of the changes in QT and QTc intervals for obese OSAHS patients undergoing Roux-en-Y Gastric Bypass (RYGB) surgery and had their weight reduced, and were treated from OSAHS post-RYGB surgery. We developed an algorithm to detect the different waveforms in the ECG signal and calculated QT and QTc intervals. Results comparing the changes in the QT and QTc pre- and post-RYGB surgery for four apneic subjects (Aged 37.0 ± 8.9 years, Pre-RYGB BMI 51.7 ± 10.1 kg/m², Post-RYGB BMI 35.6 ± 7.9 kg/m²) were contrasted with a control group of 3 non-apneic subjects (Aged 32.7 ± 7.0 years, Pre-RYGB BMI 50.8 ± 11.8 kg/m², Post-RYGB BMI 31.6 ± 2.9 kg/m²) who underwent the same surgery. The results suggest that although the RYGB surgery is successful in weight loss and OSAHS symptoms reduction, apneic patients may continue to have non-reversible LQTS despite long-term weight reduction.