Three-dimensional simultaneous strain-volume analysis describes left ventricular remodelling and its progression: a pilot study

Abstract

Aims: Three-dimensional (3D)-echocardiography speckle imaging allows the evaluation of frame-by-frame strain and volume changes simultaneously. The aim of the present investigation was to describe the strain-volume combined assessment in different patterns of cardiac remodelling.

Methods and results: Fifty patients received a 3D acquisition. Patients were classified as follows: healthy subjects (CNT), previous AMI, and normal ejection fraction (EF; group A); ischaemic cardiomyopathy with reduced EF (group B); hypertrophic/infiltrative cardiomyopathy (group C). Values of 3D strain were plotted vs. volume for each frame to build a strain-volume curve for each case. Peak of radial, longitudinal, and circumferential systolic strain (Rεp, Lεp, and Cεp, respectively), slopes of the curves (RεSl, LεSl, CεSl), and strain to end-diastolic volume (EDV) ratio (Rε/V, Lε/V, Cε/V) were computed for the analysis. Strain-volume curves of the CNT group were steep and clustered, whereas, due to progressive dilatation and reduction of strains, progressive flattening could be demonstrated in groups A and B. Quantitative data supported visual assessment with progressive lower slopes (P< 0.05 for RεSl, CεSl, P= 0.06 for LεSl) and significantly lower ratios (P< 0.01 for Rε/V, Lε/V, and Cε/V). Group C showed an opposite behaviour with slopes and ratios close to those of normal subjects. Correlation coefficients between EDV and slopes of the curves were significant for all the directions of strain (CεSl: r = 0.891; RєSl: r = 0.704; LєSl: r = 0.833; P< 0.0001 for all).

Conclusion: We measured left ventricular volumes and strain by 3D-echo and obtained strain-volume curve to evaluate their behaviour in remodelling. A distinctive and progressive pattern consistent with pathophysiology was observed. The analysis here shown could represent a new non-invasive method to assess myocardial mechanics and its relationship with volumes.

Figure 1

Schema of strain/volume curve. Values of strain (y-axis) and volume (x-axis) of each frame were plotted and curve were derived for the systolic phase. For each patient, absolute slope of the curve was calculated as the differences between peak of strain (ɛ) and end-diastolic ɛ divided by stroke volume. Ratio of peak of ɛ and EDV was also computed: ratio represents slopes of the curve considering ESV and basal ɛ equal to 0.

Figure 2

End-diastolic volume (EDVi) and circumferential peak of strain (Cɛp) with mean values (larger marker) within each group. Bar represents standard deviation. Progression of dilatation is coupled with reduction of strain (r = 0.666, P < 0.001).

Figure 3

Curve of each patient for Cɛ in normal subjects, ischemic patients with normal (group A), markedly reduced ejection fraction (group B), and hypertrophic/infiltrative cardiomyopathy (group C).

Figure 4

Relation between and end-diastolic volume and slope of curves for circumferential ɛ in CNT and ischaemic patients. Non-linear relation has been observed with a high coefficient value (r = 0.891, P < 0.0001).