Determinants of left ventricular early-diastolic lengthening velocity: independent contributions from left ventricular relaxation, restoring forces, and lengthening load.

Abstract:

BACKGROUND:Peak early-diastolic mitral annulus velocity (e') by tissue Doppler imaging has been introduced as a clinical marker of diastolic function. This study investigates whether lengthening load (early-diastolic load) and restoring forces are determinants of e' in addition to rate of left ventricular (LV) relaxation. METHODS AND RESULTS:In 10 anesthetized dogs, we measured e' by sonomicrometry and tissue Doppler imaging during baseline, volume loading, caval constriction, dobutamine infusion, and occlusion of the left anterior descending coronary artery. Relaxation was measured as the time constant (tau) of LV pressure decay by micromanometer. Lengthening load was measured as LV transmural pressure at mitral valve opening (LVP(MVO)). Restoring forces were quantified by 2 different indices: (1) As the difference between minimum and unstressed LV diameter (Lmin-L0) and (2) as the estimated fully relaxed LV transmural pressure (FRP(Est)) at minimum diameter. In the overall analysis, a strong association was observed between e' and LVP(MVO) (beta=0.49; P<0.001), which indicates an independent effect of lengthening load, as well as between e' and Lmin-L0 (beta=-0.38; P<0.002) and between e' and FRP(Est) (beta=-0.31; P<0.002), consistent with an independent contribution of restoring forces. A direct effect of rate of relaxation on e' was observed in a separate analysis of baseline, dobutamine, and ischemia when postextrasystolic beats were included (beta=-0.06, P<0.01). CONCLUSIONS:The present study indicates that in the nonfailing ventricle, in addition to LV relaxation, restoring forces and lengthening load are important determinants of early-diastolic lengthening velocity.

journal_name

Circulation

journal_title

Circulation

authors

Opdahl A,Remme EW,Helle-Valle T,Lyseggen E,Vartdal T,Pettersen E,Edvardsen T,Smiseth OA

doi

10.1161/CIRCULATIONAHA.108.791681

subject

Has Abstract

pub_date

2009-05-19 00:00:00

pages

2578-86

issue

19

eissn

0009-7322

issn

1524-4539

pii

CIRCULATIONAHA.108.791681

journal_volume

119

pub_type

杂志文章