The relationship among atrium electromechanical interval, insulin resistance, and metabolic syndrome

Metabolic syndrome (MS) is an important risk factor of atrial fibrillation. However, an understanding of the adverse effects of MS on left atrial (LA) functional assessment in terms of electromechanical interval, a convenient parameter that can reflect the process of LA remodelling, has been lacking. The goal of this study was to investigate the association between electromechanical interval and MS.

In all, 337 patients (91 with MS) with mean age of 51.9 ± 9.0 years were enrolled. Metabolic syndrome was defined by National Cholesterol Education Program-Adult Treatment Panel III score. Insulin resistance was assessed by the homeostasis model assessment-insulin resistance method. The electromechanical interval, defined as the time from initiation of P wave deflection to peak of mitral inflow Doppler A wave (PA-PDI), was measured.

Patients with MS had significantly longer PA-PDI intervals compared with those of patients without MS (131.0 ± 12.4 milliseconds vs. 123.2 ± 14.0 milliseconds, P < 0.001). Longer PA-PDI intervals were observed in subjects with higher metabolic scores (P < 0.05). In patients with small LA size, PA-PDI intervals, but not LA dimensions, were significantly different between groups with and without MS (P < 0.05). Additionally, PA-PDI interval was positively correlated with insulin resistance (r = 0.267, P < 0.001).

PA-PDI intervals were longer in patients with MS compared with those of patients without MS and tracked with insulin resistance. PA-PDI may be a useful clinical parameter to represent the degree of atrial remodelling in subjects with metabolic derangements.