Mitral systolic velocity at peak exercise predicts impaired exercise capacity in patients with heart failure with preserved ejection fraction.

Background Nearly half of patients with heart failure have normal left ventricular ejection fraction ( LVEF), but their prognosis is no better than those with reduced LVEF. Although peak oxygen consumption ( VO₂) is an independent predictor of mortality in heart failure, it is unclear how cardiac function during exercise contributes to peak VO₂. Therefore, we explored the useful parameters measured by exercise stress echocardiography to predict peak VO₂ in patients with heart failure with preserved LVEF ( HFp EF). Methods and Results We assessed 80 patients being investigated for effort intolerance or dyspnea and finally analyzed 50 patients who satisfied the HFp EF criteria. Mean peak VO₂ was 16.4±2.8 mL/kg/min. Twenty-three patients (46.0%) achieved a peak VO₂ <16.0 mL/kg/min (Weber class C or D). There was a significant relationship between mitral systolic velocity (S′) and cardiac output ( CO) at rest ( R=.55, P<.0001) and peak exercise ( R=.64, P<.0001). The absolute increase in S′ from rest to peak exercise also correlated with the absolute increase in CO ( R=.32, P=.02). Multivariate logistic regression analysis showed that S′ at peak exercise independently predicted peak VO₂. Receiver-operator characteristic curve analysis identified that an S′ at peak exercise of ≤8.13 cm/s predicted a peak VO₂ <16.0 mL/kg/min (sensitivity 95.7%, specificity 44.4%, area under curve 0.70, 95% confidence interval 0.55-0.84, P=.004). Conclusions Mitral systolic velocity at peak exercise accurately reflects peak VO₂ and may facilitate stratification of risk in patients with HFp EF. [ABSTRACT FROM AUTHOR]