COMPARISON OF PEAK OXYGEN CONSUMPTION AND VENTILATORY THRESHOLD IN ELDERLY SUBJECTS WITH NORMAL VENTRICULAR FUNCTION, SYSTOLIC DYSFUNCTION, OR DIASTOLIC DYSFUNCTION 441

Abstract

Peak oxygen consumption and ventilatory threshold (VT) have prognostic and functional implications in patients with left ventricular systolic dysfunction(SD). Although younger patients with SD have been well studied, there is little data on elderly patients with SD or on patients with primary diastolic dysfunction (DD), a common cause of congestive heart failure (CHF) in the elderly. Consequently, we compared 114 consecutive elderly patients (mean age=70 yrs) with stable (NYHA class II - III) CHF due to SD (n=55) or DD(n=59) at baseline of a NIH sponsored trial to 31 age-matched normal subjects(NL). All subjects underwent screening echocardiograms to exclude significant ischemia and valvular disease and for measurement of resting left ventricular ejection fraction (LVEF). Subjects were tested to symptom-limited maximal levels on a calibrated bicycle ergometer while expired gases were collected breath-by-breath with a Medical Graphics CPX system. Peak oxygen consumption values were the highest value obtained during a 15 sec. interval and VT was determined by a blinded observer using the “v-slope” method and traditional ventilatory and gas exchange variables. VT was identifiable in 100% of NL and 85% of CHF patients. Data are presented as mean± SD.Table Conclusion: Peak oxygen consumption and ventilatory threshold in elderly patients with CHF due to DD are severely reduced compared to age-matched NL and are similar to what is observed in patients with SD.