Stability of left ventricular longitudinal and circumferential deformation over time and standard loading conditions.

Aims: Load dependence is an important source of variation in left ventricular (LV) deformation. This impacts on the precision of information obtained from serial measurements. However, it is clinically important to distinguish actual myocardial dysfunction from changes associated with altered loading conditions. We sought to investigate the association of changes of loading parameters with changes in LV longitudinal (GLS) and circumferential (GCS) strains.
Methods and Results: Baseline and a 12-month follow-up 2D echocardiograms were performed in 191 Stage A heart failure patients with uncomplicated hypertension. These patients underwent simultaneous measurement of conventional and central blood pressures (BPs) and haemodynamic measurements by applanation tonometry. Significant, but weak correlations (r = 0.15-0.28) of LV strain parameters and their changes over the follow-up period were shown for the majority of LV afterload-associated variables, including central and brachial systolic, diastolic, and mean BPs; 24-h systolic and diastolic BPs; peak reservoir and excess pressures; central augmented pressure (CAP) and pulse pressure; augmentation index; and arterial elastance index (EaI). Central mean BP, EaI, and changes in CAP and EaI over follow-up were independent contributors to LV deformation in multivariable analysis. No improvement in the Bland-Altman 95% limits of agreement and correlation coefficients was seen with LV afterload correction of GLS and GCS using central BP indices.
Conclusions: LV longitudinal and circumferential strains in a population without apparent heart disease is relatively insusceptible to changes in LV afterload within physiological range, which, therefore, seem unlikely to be a significant confounder in repeated GLS or GCS observations.
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