Cardiac Diastolic Function Is Impaired at Rest and Worsens With Exercise in Otherwise Healthy Individuals With Insulin Resistance

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Insulin resistance (IR) is a pathophysiological condition and is associated with cardiovascular risk factors including heart failure. However, studies demonstrating myocardial abnormalities in the early phases of IR are limited. The aim of this study was to investigate myocardial function in otherwise healthy individuals with IR.
Individuals with IR who were free of cardiovascular risk factors and healthy controls were included. Stress echocardiography with tissue Doppler imaging (TDI) was performed. Systolic and diastolic TDI waves were compared in both groups.
A total of 77 individuals (51 with IR and 26 controls) were included in our study. The tissue early flow (e’)/atrial contraction (a’) ratio at rest was significantly lower in the IR group (P = 0.003). The annular early flow (E)/e’ ratio, a predictor of left ventricular filling pressure, was similar in both groups at rest (P = 0.522). After exercise, e’/a’ impairment became more prominent in the IR group (P < 0.001); whereas the E/e’ ratio was also significantly lower (7.6 ± 1.8 versus 6.7 ± 0.9; P = 0.007) in the IR group.
Myocardial involvement seems to occur in patients with IR, before the appearance of other cardiovascular risk factors. Exercise induced diastolic worsening may be a predictor of reduced compliance and increased ventricular stiffness. More detailed prospective studies are required for more precise results.