EXERCISE PERFORMANCE IN PATIENTS WITH DILATED CARDIOMYOPATHY - RELATIONSHIP TO RESTING LEFT-VENTRICULAR FUNCTION

Relationship between maximal exercise tolerance and resting indexes of left ventricular systolic and diastolic function were evaluated in 35 men, aged 55.1+/-10.4 years, with dilated cardiomyopathy. Clinical di agnosis of dilated cardiomyopathy was confirmed with M-mode echocardio graphy (M-mode echocardiographic end-diastolic dimension >55 mm, fract ional shortening <25%, increased E point septal separation). Coronary angiography was considered mandatory for exclusion of patients with co ronary artery disease. Patients with mitral regurgitation (greater tha n or equal to grade 2) and rhythm other than sinus were excluded. Acco rding to the functional classification of New York Heart Association 6 patients were in class I, 11 in class II, 12 in class III and 6 in cl ass IV. Left ventricular ejection fraction (LVEF), stroke volume (SV) and left ventricular end-diastolic pressure (LVEDP) were measured with contrast angiography. Peak early (VE) and late (VA) transmitral filli ng velocities and their ratio (E/A), isovolumetric relaxation time (IR T) and deceleration time (DT) were computed from pulsed wave Doppler e chocardiograms. On completion of all resting measurements, patients un derwent symptom limited upright treadmill exercise testing using a mod ified Naughton protocol and maximal exercise performance metabolic equ ivalent work load (NETS) was calculated from the speed, incline and le ngth of time at the stage using standard tables to make interpatient c omparisons. Significant correlation has been found between NYHA class and METS (r= -0.77, P<0.001). However NYHA class II and NYHA class III patients were found to have similar METS (P=0.317). Patients were fur ther divided into two groups on the basis of exercise data. Group I co nsisted of 22 patients with relatively preserved exercise tolerance (g reater than or equal to 4 METS) and Group II included 13 patients with impaired exercise tolerance (greater than or equal to 4 METS). This a rbitrary classification was based upon previously described survival d ifferences in these two groups. There were no differences between two groups in terms of age, gender distribution tall were male), heart rat e and arterial blood pressure. LVEF, LVEDP stroke volume, VE, VA, E/A, IRT and DT were also similar between two groups. Strong positive corr elation was observed between LVEDP and VE (r=0.74) while IRT and VA ne gatively correlated with LVEDP (r=-0.77 and r=-0.81 respectively) but neither of resting indexes of left ventricular systolic and diastolic function showed significant correlation with METS and exercise duratio n. (C) 1998 Elsevier Science B.V.