Aims: Heart failure patients with reduced and preserved left ventricular (LV) ejection fraction (EF) show reduced exercise capacity. We explored the relationship between exercise capacity and systolic and diastolic myocardial function in heart failure patients.
Methods and results: Exercise capacity, by peak oxygen uptake (VO2), was assessed in 100 patients (56 ± 12 years, NYHA functional class: 2.5 ± 0.9, EF: 42 ± 19%). LV systolic function, as EF and global longitudinal strain (GLS), and right ventricular function were assessed by echocardiography. Left atrial volume index and the ratio of peak early diastolic filling velocity (E) to early diastolic mitral annular velocity (e') were measures of diastolic function. Thirty-seven patients had heart failure with preserved EF (HFpEF), defined as EF ≥50% and echocardiographic diastolic dysfunction. LV GLS and peak pulmonary arterial systolic pressure were independently correlated to peak VO2 in the total study population and in HFpEF separately. LV GLS was superior to EF in identifying patients with impaired peak VO2 <20 mL/kg/min as shown by receiver operating characteristic analyses [areas under curves 0.93 (0.89-0.98) vs. 0.85 (0.77-0.93), P < 0.05]. In patients with HFpEF, GLS was reduced below normal (-17.5 ± 3.2%) and correlated to E/e' (R = 0.45, P = 0.005) and left atrial volume index (R = 0.48, P = 0.003), while EF did not.
Conclusion: GLS correlated independently to peak VO2 in patients with reduced and preserved EF and was superior in identifying patients with reduced exercise capacity. In HFpEF, systolic function by GLS was impaired. There was a significant relationship between diastolic function and GLS, confirming a coupling between diastolic and longitudinal systolic function in HFpEF.
Keywords: diastolic function; exercise testing; heart failure; myocardial mechanics; speckle tracking echocardiography.
© The Author 2014. Published by Oxford University Press on behalf of the European Society of Cardiology.