Echocardiographic evidence of left ventricular untwisting-filling interplay

Abstract

Background: Left ventricular untwisting generates an early diastolic intraventricular pressure gradient (DIVPG) than can be quantified by echocardiography. We sought to confirm the quantitative relationship between peak untwisting rate and peak DIVPG in a large adult population.

Methods: From our echocardiographic database, we retrieved all the echocardiograms with a normal left ventricular ejection fraction, for whom color Doppler M-Mode interrogation of mitral inflow was available, and left ventricular untwisting rate was measurable using speckle tracking. Standard indices of left ventricular early diastolic function were assessed by Doppler (peaks E, e' and Vp) and speckle tracking (peak strain rate Esr). Load dependency of DIVPG and untwisting rate was evaluated using a passive leg raising maneuver.

Results: We included 154 subjects, aged between 18 to 77 years old, 63% were male. Test-retest reliability for color Doppler-derived DIVPG measurements was good, the intraclass correlation coefficients were 0.97 [0.91-0.99] and 0.97 [0.67-0.99] for intra- and inter-observer reproducibility, respectively. Peak DIVPG was positively correlated with peak untwisting rate (r = 0.73, P < 0.001). On multivariate analysis, peak DIVPG was the only diastolic parameter that was independently associated with untwisting rate. Age and gender were the clinical predictive factors for peak untwisting rate, whereas only age was independently associated with peak DIVPG. Untwisting rate and DIVPG were both load-dependent, without affecting their relationship.

Conclusions: Color Doppler-derived peak DIVPG was quantitatively and independently associated with peak untwisting rate. It thus provides a reliable flow-based index of early left ventricular diastolic function.

Keywords: Color Doppler M-mode; Diastolic function; Intraventricular pressure gradient; Untwisting rate.

Fig. 1

Measurement of left ventricular untwisting rate using speckle tracking a: Speckle tracking of left ventricular rotation in the short-axis view, at the basal and the apical levels (the arrows indicate the untwisting direction). b: Rotation rate curves from speckle tracking analysis.

Fig. 2

Semi-automatic assessment of peak DIVPG using color Doppler M-mode echocardiograms post-processed with custom software

Fig. 3

Relationship between peak DIVPG and peak untwisting rate in the entire population

Fig. 4

Relationship between peak DIVPG and peak untwisting rate depending on age, gender, training status, and personal history of hypertension The comparison of correlation coefficients was analyzed using Fisher’s Z-transformation.

Fig. 5

Correlations between peak DIVPG and the standard parameters of left ventricular early diastolic function and filling

Fig. 6

Correlations between peak untwisting rate and the standard parameters of left ventricular early diastolic function and filling

Fig. 7

Relationship between DIVPG and untwisting rate during a passive leg raising maneuver. Mean peaks DIVPG and untwisting rate increased significantly after a passive leg raising in 20 healthy volunteers (left, *P < 0.001), without altering the correlation between the magnitudes of peak untwisting rate and peak DIVPG (right). Each pair of resting and leg raising states was connected by a line