Global dyssynchrony correlates with compromised left ventricular filling and stroke volume but not with ejection fraction or QRS duration in HFpEF

Abstract

Background and Aim: Mechanical global left ventricular (LV) dyssynchrony reflected as prolonged total isovolumic time<br />(t-IVT) has been introduced as a potential mechanism behind compromised stroke volume in heart failure (HF). It has also<br />been shown to be superior to other markers of dyssynchrony in predicting response to cardiac resynchronization therapy<br />(CRT), but its application in HF with preserved ejection fraction (HFpEF) remains unknown. The aim of this study was to<br />assess the role of t-IVT in explaining symptoms in HFpEF.<br />Methods: In 55 symptomatic HFpEF patients (age 60±9 years, NYHA class II-IV; LV EF ≥45%) and 24 age and gender<br />matched controls, a complete Doppler echocardiographic study was performed including mitral annulus peak systolic<br />excursion (MAPSE) and myocardial velocities as well as LV filling, outflow tract velocity time integral (VTI) and stroke volume<br />measurements. Global LV dyssynchrony was assessed by t-IVT [in s/min; calculated as: 60 - (total ejection time + total filling<br />time)], Tei index (t-IVT/ejection time) and pre-ejection time difference between LV and RV.<br />Results: Patients had reduced lateral and septal MAPSE (p=0.009 and p=0.01, respectively) lower lateral and septal s’<br />(p=0.002 and p=0.04, respectively) and e’ (p&lt;0.001, for both) velocities and higher E/e’ ratio (p=0.01) compared to controls.<br />They also had longer t-IVT (p&lt;0.001), higher Tei index (p=0.04), but similar pre-ejection time difference and LVEF to controls.<br />T-IVT correlated with LV filling time (r=0.44, p&lt;0.001), stroke volume (r=-0.41; p=0.002), MAPSE (lateral: r=-0.36, p=0.007 and<br />septal: r=-0.31; p=0.02), but not with LV mass index, LVEF, E/e’ ratio or QRS duration.<br />Conclusion: Patients with HFpEF have exaggerated global mechanical dyssynchrony shown by prolonged t-IVT, compared<br />with healthy age and gender matched controls. The relationship between t-IVT, LV filling and stroke volume suggests an<br />association, more important than with ejection fraction or electrical dyssynchrony. These results support the importance of<br />the individualistic approach for optimum HFpEF patient management.