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Global strain rate imaging for the estimation of diastolic function in HFNEF compared with pressure-volume loop analysis.

AIMS
Strain rate imaging provides direct information on intrinsic myocardial function and may improve the diagnostic of diastolic dysfunction in heart failure with normal ejection fraction (HFNEF). We therefore correlated global strain with pressure-volume (PV) loop analysis and compared it with flow and tissue Doppler measurements.


METHODS AND RESULTS
Longitudinal two-dimensional strain rate and flow and tissue Doppler (TDI) indices were measured simultaneously and correlated with diastolic indices of PV relationship obtained by a conductance catheter in 21 patients with HFNEF and 12 controls. HFNEF patients showed a reduced global strain rate during isovolumetric relaxation (SR(IVR)) [0.27 (0.12-0.39) vs. 0.44 (0.29-0.56) s(-1), P = 0.028]. Global strain rate during early (SR(E)) and late (SR(L)) diastole did not defer from controls. Their ratios with early transmitral flow, E/SR(IVR) and E/SR(E), were both elevated in HFNEF [3.68 (2.57-7.52) vs. 1.73 (1.47-2.37) m, P = 0.007 and 1.13 (0.76-1.36) vs. 0.83 (0.57-1.04) m, P = 0.030]. SR(E) and SR(IVR) correlated with left ventricular (LV) relaxation τ (r = 0.40 and 0.47, P < 0.05); E/SR(IVR) and E/SR(E) with LV end-diastolic pressure (r = 0.49 and 0.57, P < 0.01) and LV stiffness constant β (r = 0.42 and 0.43, P < 0.01). Neither of the strain rate indices were significantly more accurate than TDI (area under the curve: SR(E) 0.55, SR(IVR) 0.70, E'/A' 0.72, E/SR(E) 0.75, E/SR(IVR) 0.80, and E/E' 0.83).


CONCLUSION
Strain rate imaging is accurate in detecting increased LV stiffness in HFNEF, but it is not superior to already established TDI analysis including E/E' in patients with only mild degree of disease.