The relationship between echocardiographic epicardial adipose tissue, P-wave dispersion, and corrected QT interval

OBJECTIVE
Epicardial adipose tissue (EAT) secretes various pro-inflammatory and atherogenic substances that have several effects on the heart. The goal of this study was to evaluate the association between EAT thickness and both P-wave dispersion (Pd) and corrected QT interval (QTc), as simple, non-invasive indicators of arrhythmia on a surface electrocardiogram.

METHODS
This retrospective observational study included 216 patients who had normal coronary arteries observed on coronary angiography. Each patient underwent 12-derivation electrocardiography to measure Pd and QTc, and transthoracic echocardiography to measure EAT thickness. The patients were divided into 2 groups according to the median EAT value (EAT low group: <5.35 mm; EAT high group: ≥5.35 mm).

RESULTS
P-wave dispersion (p=0.001) was significantly greater in the EAT high group compared with the EAT low group. However, the QTc (p=0.004) was significantly greater in the latter group. The median left ventricular end-diastolic diameter (p=0.033), mean left ventricular end-systolic diameter (p=0.039), and mean left atrial diameter (p=0.012) were significantly greater in the EAT high group. Multiple logistic regression analysis using the backward elimination method revealed that the leukocyte count (Odds ratio [OR]: 1.000; 95% confidence interval [CI]: 1.000–1.000; p=0.001), Pd (OR: 1.1026; 95% CI: 1.010–1.043; p=0.002), QTc interval (OR: 0.988; 95% CI: 0.979–0.997; p=0.009), and left ventricular ejection fraction (OR: 0.922; 95% CI: 0.859–0.989; p=0.023) were independently associated with greater EAT thickness.

CONCLUSION
Echocardiographic end-diastolic EAT thickness on the free wall of the right ventricle was associated with Pd and QTc in patients with normal coronary arteries.