Left ventricular diastolic dysfunction is related to oxidative stress and exercise capacity in hypertensive patients with preserved systolic function.

BACKGROUND

Left ventricular diastolic dysfunction and oxidative stress are important determinants in heart failure development. Peak oxygen uptake, maximal oxygen consumption, metabolic equivalents (MET), ventilatory response and time to respiratory gas exchange assess cardiopulmonary capacity.

AIM

It was the aim of this study to investigate the impact of oxidative stress on diastolic indexes and cardiopulmonary exercise capacity in hypertensive patients with left ventricular diastolic dysfunction.

METHODS

Mitral flow velocities (E, A), ejection fraction, left atrial and ventricular diameters were assessed by Doppler echocardiography. Superoxide dismutase (SOD) and glutathione peroxidase activity in blood were evaluated. Sixty patients (aged 49.8 +/- 9.2 years) with essential hypertension and preserved systolic function (ejection fraction 58.3 +/- 7%) performed a bicycle exercise test. Forty patients showed impaired left ventricular relaxation (E/A <1, deceleration time of E >220 ms) and were assigned to group 1, while 20 had normal relaxation (group 2).

RESULTS

An increase in SOD was significantly blunted after exercise in group 1 compared with group 2 (p = 0.049). A significant difference between groups in the glutathione peroxidase level was observed before exercise (p = 0.038). There were significantly lower values of peak oxygen uptake and MET (p = 0.013 and p = 0.024, respectively) and a prolonged respiratory exchange ratio (p = 0.022) in group 1 compared with group 2. MET was significantly influenced by SOD level (p = 0.035).

CONCLUSIONS

Lower antioxidative protection and impaired relaxation decrease cardiopulmonary capacity in hypertensive patients.