MAXIMAL EXERCISE TOLERANCE IN CHRONIC CONGESTIVE-HEART-FAILURE - RELATIONSHIP TO RESTING LEFT-VENTRICULAR FUNCTION

The relationship between maximal exercise tolerance and resting radion uclide indexes of left ventricular systolic and diastolic function wer e evaluated in 20 ischemic and 44 idiopathic cardiomyopathy patients w ith New York Heart Association class 2-4 chronic congestive heart fail ure. Left ventricular ejection fraction, peak systolic ejection rate, peak diastolic filling rate, time to peak filling from end-systolic vo lume, and fractional filling in early diastole were measured from the radionuclide ventriculogram. All patients underwent symptom-limited ex ercise testing with on-line measurement of oxygen consumption. In the ischemic group, all of the radionuclide indexes correlated poorly with maximal exercise oxygen consumption (Vo(2)max) except the peak systol ic ejection rate which correlated modestly (r=0.58, p<0.05). Peak syst olic ejection rate was significantly lower (p<0.01) as were the peak d iastolic filling rate and fractional filling in the first third of dia stole (p<0.05) in ischemic patients with marked exercise intolerance ( Vo(2)max less than or equal to 14 mL/kg/min) compared with those with preserved exercise tolerance (Vo(2)max >14 mL/kg/min). In the idiopath ic group, none of the radionuclide indexes correlated well with Vo(2)m ax; and all indexes were similar in patients with and without marked e xercise intolerance. These data suggest that (1) resting left ventricu lar ejection fraction poorly predicts maximal exercise capacity in bot h ischemic and idiopathic cardiomyopathy and (2) resting peak systolic ejection rate, peak diastolic filling rate, and fractional filling in early diastole may predict exercise tolerance in ischemic but not idi opathic cardiomyopathy.