Impact of diabetes and diastolic dysfunction on exercise capacity in normotensive patients without coronary artery disease

Objective: The aim of this study was to determine the impact of diabetes and diastolic dysfunction on exercise capacity in asymptomatic, normotensive patients with type 2 diabetes without coronary artery disease. Methods: A total of 43 type 2 diabetes patients (age: 505years) and 20 healthy controls (age: 484years) were enrolled. Diastolic function was investigated by conventional pulsed-wave (PW) Doppler and tissue Doppler imaging (TDI). Exercise capacity was evaluated with cardiopulmonary exercise testing (CPET). Results: In patients with type 2 diabetes, increase in resting heart rate (HR-rest) (p=0.013), decrease in maximum heart rate during exercise (HR-max) (p<0.001) and exercise time (p<0.001) compared with controls were significant. Patients had significantly increased minute ventilation volume (VE)/maximum carbon dioxide discharge (VCO2) ratio (p<0.001), decreased maximum oxygen consumption (VO2-max) (p<0.001), oxygen consumption at anaerobic threshold (VO2-an) (p<0.001) and maximum carbon dioxide discharge (VCO2) (p<0.001) compared to controls indicating significantly reduced exercise capacity. HbA1c was inversely correlated with VO2-max (r=-0.456, p<0.01) independent of the absence or presence of mild diastolic dysfunction. Conclusion: Exercise capacity was found to be significantly decreased in normotensive patients with type 2 diabetes without coronary artery disease, and this decrease was independent of diastolic dysfunction.