CORRELATION BETWEEN VENTRICULAR FUNCTION AS ASSESSED BY ECHOCARDIOGRAPHY AND 6 -MINUTE WALK TEST AS SURROGATE OF EXERCISE CAPACITY IN COPD PATIENTS

Abstract

Exercise intolerance is common in COPD patients, and has multiple mechanisms underlying its progression. Ventricular dysfunction may play a role in development of exercise incapacity in COPD patients. Aim: to investigate the possible contribution of left and right ventricular dysfunction (either systolic or diastolic) in development of exercise intolerance in COPD patients. Methods: 60 patients with diagnosis of COPD were categorized according to GOLD spirometeric stage to 2 groups (group 1: mild to moderate COPD, group2: severe to very severe COPD). Both groups were evaluated by spirometry, ECG, CXR, routine lab., six minute walk test and echocardiography including Tissue Doppler Imaging. Results: The average age in the whole study group was 56.63±10.33 years. Male patients in the study were 46 (76.7%) and female patients were 14 (23.3%). Mean maximum walk distance among the whole group was 342.75 ± 54.85 meter. There was significant correlation between 6 minute walk distance and transtricuspid E velocity , tricuspid E/A and transtricusped deceleration time (P-value = 0.011, 0.015 and 0.021 respectively). There was no significant correlation between 6 minute walk distance and parameters of LV diastolic dysfunction. Prevalence of ventricular dysfunction was as follow: LV systolic Dysfunction 3.3%, LV diastolic dysfunction 30%, RV systolic dysfunction 21% and RV diastolic dysfunction 46%. Conclusion: Right ventricular diastolic dysfunction may be a contributing factor in progression of exercise intolerance in COPD. Although left ventricular diastolic dysfunction may not be associated with exercise intolerance, It is still prevalent in COPD and must be assessed and managed through the course of the disease and especially during exacerbation.