Left ventricular strain modifications after maximal exercise in athletes: a speckle tracking study.

Purpose: The increase in systolic indexes from rest (R) to exercise is achieved by combination of enhanced heart rate (HR) and stroke volume (SV). Aim of this study was to evaluate left ventricular (LV) longitudinal, circumferential, and torsional components immediately after a maximal intensity exercise (ME) by speckle tracking echocardiography (STE).

Methods: Twenty-seven male water polo players performed an ME that consisted of 6 repeats of 100 m freestyle swim sets. An echocardiographic examination was performed before and after ME. STE was performed to obtain the analysis of LV myocardial deformation.

Results: There were no differences between R and ME regarding LV longitudinal strains (PVLS). Apical circumferential LV strain (AVCS) and LV longitudinal strain rate (SR) increased at ME with respect to R (R: -23.1 ± 4.9%; ME: -28.4 ± 7.6%, P < 0.05; R: -1.1 ± 0.1/sec, ME: -1.5 ± 0.2/sec, P < 0.01). LV twisting (LVT) and untwisting (UTW) increased at ME (R: 7.9 ± 2.4°, ME: 14.2 ± 3.2°, P < 0.001; R: -107.2 ± 47.4; ME: -158.5 ± 61.5 °/sec; P < 0.01). At ME, apical rotation (Arot) had higher values than R values (5.4 ± 3.0°; 10.0 ± 6.0°; P < 0.01) and time-to-peak (TTP) of apical segments are earlier than all TTP. SV was related to LVT (r = 0.56, P = 0.01), AVCS (r = -0.59, P = 0.005) and Arot (r = 0.46, P = 0.04). At multivariate analysis, AVCS was the independent predictor of SV (β = -0.58; P < 0.05).

Conclusions: Apical fibers and LVT give the main contribution to systolic components at ME. The storage of energy during LVT, released during early diastole, seems to be a fundamental mechanism to support diastolic filling during maximal exercise.