Background—: The dynamics of systolic and diastolic strains and torsional mechanics of the left ventricle (LV) and their relation to diastolic filling never have been evaluated at various exercise intensities. Methods and Results—: Speckle tracking echocardiography was performed in 20 healthy sedentary subjects at rest and during a progressive submaximal exercise test at 20%, 30%, and 40% of maximal aerobic power. LV twist increased progressively with exercise intensity (10.5±3.2 to 15.8±4.5°; P <0.001), whereas longitudinal strain remained unchanged after the first workload, underlining the key role of torsional reserve in systolic-diastolic coupling during exercise. The increase in diastolic untwisting (−88.7±34.2 to −182.9±53.5 deg · s ⁻¹ ; P <0.01) was correlated to enhanced systolic twist ( R =0.61; P <0.001), and its magnitude of increase was significantly higher compared to diastolic longitudinal and circumferential strain rates (119±64% versus 65±44% and 57±24%, respectively), emphasizing its contribution to diastolic filling. The timing of peak untwisting and the chronology of diastolic mechanical events were unchanged during effort. Untwisting was driven mainly by apical rotation and determined mitral opening and isovolumic relaxation time ( R =0.47 and 0.61, respectively; P <0.001), whereas basal rotation and longitudinal and circumferential diastolic strain rates were major determinants of increased early diastolic filling ( R =0.64, 0.79, and 0.81, respectively; P <0.001). Conclusions—: The use of speckle tracking echocardiography gives new insights into physiological adaptive LV mechanics during incremental exercise in healthy subjects, underlining the key role of torsional mechanics. It might be useful to better understand the mechanisms of diastolic dysfunction and exercise intolerance in various pathological conditions.

Background— Numerous studies have reported evidence of cardiac injury associated with transient left ventricular (LV) systolic and diastolic dysfunction after prolonged and strenuous exercise. We u...

Investigations on the cardiac function consequences of mountain ultramarathon (MUM) >100 h are lacking. The present study assessed the progressive cardiac responses during the world's most challenging MUM (Tor des Géants; Italy; 330 km; 24,000 m of cumulative elevation gain). Resting echocardiographic evaluation of morphology, function, and mechanics of left and right ventricle (LV and RV) including speckle tracking echocardiography was conducted in 15 male participants (46 ± 13 yr) before (pre), during (mid; 148 km), and after (post) the race. Runners completed the race in 126 ± 15 h. From pre to post, the increase in stroke volume (SV) (103 ± 19 vs. 110 ± 23 vs. 116 ± 21 ml; P < 0.001 at pre, mid, and post) was concomitant to the increase in LV early filling ( peak E; 72.9 ± 15.7 vs. 74.6 ± 13.1 vs. 82.1 ± 11.5 cm/s; P < 0.05). Left and right atrial end-diastolic areas, RV end-diastolic area, and LV end-diastolic volume were 12–19% higher at post compared with pre ( P < 0.05). Resting heart rate and LV systolic strain rates demonstrated a biphasic adaptation with an increase from pre to mid (55 ± 8 vs. 72 ± 11 beats/min, P < 0.001) and a return to baseline values from mid to post (59 ± 8 beats/min). Significant correlations were found between pre-to-post percent changes in peak E and LV end-diastolic volume ( r = 0.63, P < 0.05) or RV ( r = 0.82, P < 0.001) or atrial end-diastolic areas ( r = 0.83, P < 0.001). An extreme MUM induced a biphasic pattern of heart rate in parallel with specific cardiac responses characterized by a progressive increase in diastolic filling, biventricular volumes, and SV. The underlying mechanisms and their clinical implications remain challenging for the future.

In children and adults, endurance training increases resting stroke volume, mainly as a result of an increase in left ventricular (LV) filling. To evaluate whether the LV morphologic and functional alterations responsible for this increase in cardiac filling are similar in children and young adults. Standard echocardiography (LV morphology and function) and tissue Doppler imaging (LV relaxation properties) were assessed in 10 adult cyclists, 13 age-matched sedentary controls, 12 boy cyclists, and 11 untrained boys. In our endurance-trained adults, LV morphological adaptations included increase in LV internal diameters, wall thickness, and mass. However, effects associated with training on LV morphology were different in children because no true cardiac hypertrophy was observed in our child cyclists compared with age-matched nonactive boys. Effects related training on LV systolic and diastolic function assessed by TDI were similar in boys and men. The LV diastolic function was improved in trained subjects (i.e., increased transmitral early to late filling velocities) as a result of an increase in LV relaxation properties. However, LV filling pressures, estimated from TDI, were similar in trained individuals compared with age-matched controls. In both children and adults, an increase in LV relaxation properties and normal LV filling pressures in endurance-trained subjects might be taken as additional indicators for a physiologic or "normal" hypertrophy. However, further investigations are needed to evaluate whether the specific LV morphological adaptation observed in trained-children reflects a blunted trained-induced cardiac hypertrophy before puberty.