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Cardiac function and pulmonary hemodynamics during exercise in COPD

Background COPD is often associated with changes of the structure and the function of the heart. Although functional abnormalities of the right ventricle have been well described in COPD patients with severe hypoxemia, little is known about these changes in patients with normal to mild hypoxemia. Study objectives To assess the structural and functional cardiac changes in COPD patients with normal partial pressure of arterial oxygen and without signs of right ventricular failure. Methods In 25 clinically stable COPD patients (FEV1 : 1.23 ± 0.51 l/s, PaO2: 82 ± 10 mm Hg) and 26 age-matched control subjects, the right and left ventricular structure and function were measured by MRI. Pulmonary artery pressure was estimated from right pulmonary artery distensibility. Results Right ventricular mass divided by right ventricular end-diastolic volume as a measure of right ventricular adaptation was 0.72 ± 0.18 g/ml in the COPD group and 0.41 ± 0.09 g/ml in the control group (p<0.01). Left and right ventricular ejection fraction were 62 ± 14% and 53 ± 12 % in the COPD patients, and 68 ± 11% and 53 ± 7% in the controls. Pulmonary artery pressure (Ppa) estimated from right pulmonary artery distensibility was not elevated in the COPD group. Conclusion From these results we conclude that concentric right ventricular hypertrophy is the earliest sign of right ventricular pressure overload in COPD. This structural adaptation of the heart does not alter right and left ventricular systolic function. 24 Cardiac function and pulmonary hemodynamics during exercise in COPD Scriptie Bas 10-08-2007 12:51 Pagina 24