Myocardial systolic and diastolic consequences of left ventricular mechanical dyssynchrony in heart failure with normal left ventricular ejection fraction

Abstract

Aims: The purpose of this study was to test the hypothesis that left ventricular (LV) mechanical dyssynchrony deteriorates the longitudinal systolic and diastolic function of the left ventricle (LV) in patients with heart failure with a normal LV ejection fraction (HFNEF).

Methods and results: In patients with HFNEF and in a control group consisting of asymptomatic patients with LV diastolic dysfunction [LVDD], matched by age, gender, and LV ejection fraction, we assessed the global longitudinal systolic (global strain), diastolic [global early-diastolic strain rate (SRe)], and synchronous (standard deviation of time-to-peak systolic strain) function of the LV by two-dimensional speckle-tracking echocardiography using a 18-segment LV model. A total of 325 patients were included (85 with HFNEF and 240 with asymptomatic LVDD). Patients with HFNEF had a significant impairment of the longitudinal systolic and diastolic function of the LV as compared with the control group. Concerning the pathophysiological mechanisms linked to these findings, we found that HFNEF patients with asynchronous LV contractions had significantly more impaired longitudinal systolic and diastolic LV function (global strain -14.76 ± 3.44%, global SRe 0.79 ± 0.24 s(-1)) than patients without asynchronous LV contractions (global strain -18.57 ± 3.10%, global SRe 1.06 ± 0.32 s(-1); all P < 0.0001). Accordingly, in HFNEF patients with LV mechanical dyssynchrony the rates of LV longitudinal systolic and diastolic dysfunction were 64 and 70%, respectively, whereas these rates were significantly lower (19.5 and 41.3%), respectively, in patients without asynchronous LV contractions. In addition, HFNEF patients with LV mechanical dyssynchrony presented higher LV filling pressures and worse NYHA functional class than those with normal LV contractions.

Conclusion: In patients with HFNEF, LV mechanical dyssynchrony is associated with an important impairment of the longitudinal systolic and diastolic function of the LV. Therefore, the restoration of asynchronous LV contractions could help to improve and/or correct both the systolic and the diastolic longitudinal dysfunction of the LV in HFNEF and thereby improve the symptomatology of these patients.