Purpose .– Although heart failure with normal ejection fraction (HFNEF) is a frequent disease, physiopathologic mechanisms are still controversial. We hypothesized that elevated arterial stiffness and impaired diastolic reserve could explain symptoms at exercise.
Methods .– From our heart failure clinic (614 patients), we selected 85 patients with a HFNEF syndrom (ESC 2007 criteria). Thirty-two were on sinus rhythm and could perform an echocardiography at rest and peak exercise with measurement of diastolic transmitral parameters (E and A), and tissue Doppler velocities (early diastolic Ea, and systolic Sa). Central arterial stiffness parameters were assessed noninvasively by tonometry: carotidofemoral pulse wave velocity (PWVcf), central pulse pressure (PP), and Augmentation Index (AIx@75). Distance during a six-minute walking test (6MWT) and a semi-quantitative assessment of peak exercise dyspnoea evaluated functional performances.
Results .– Mean age was 76 ± 11 years, with a high prevalence of hypertension (66%). PWVcf was increased at 10 ± 2.3m/s, and distance at 6MWT was 373 ± 114 m. In univariate analysis, distance correlated with PWVcf (R = −0.82, P < 0.0001), heart rate at rest (R = −0.39, P = 0.045), and E/Ea at rest (R = −0.48, P = 0.012) but almost at peak exercise (R = −0.61, P < 0.01). Exertional dyspnoea correlated with PWVcf too ( P = 0.025), and with diastolic and systolic parameters measured at peak exercise (E/Ea: P = 0.02; Sa: P = 0.014). In multivariate analysis, PWVcf was the strongest predictor of distance at 6MWT, with a lower influence of heart rate, and no significant influence of diastolic and systolic functions.
Conclusion .– In HFNEF, different interlinked mechanisms can lead to functional limitation and dyspnoea at exercise, but central arterial compliance and ventricular-arterial coupling impairment play a key role.
