Endurance-trained subjects and sedentary controls increase ventricular contractility and efficiency during exercise: Feasibility of hemodynamics assessed by non-invasive pressure-volume loops

Figures

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  Fig 1. Schematic figure of a left ventricular pressure-volume loop with cardiovascular hemodynamics marked. Dashed lines indicate the slopes of maximal ventricular elastance (Emax) and arterial elastance (EA). EA: arterial elastance; Emax: maximal ventricular elastance; LV: left ventricular; PE: potential energy; SW: stroke work.

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  Fig 2. Left ventricular response in endurance-trained (ET) subjects and sedentary controls (SC) from rest to exercise. A) left ventricular end-diastolic volume (LVEDV), and B) left ventricular end-systolic volume LVESV). Endurance-trained increased LVEDV and decreased LVESV during moderate exercise compared to rest, whereas sedentary controls had unchanged LVEDV and decreased LVESV. Individual values are plotted, and error bars denote median [IQR]. P-values indicate Wilcoxon signed-rank test comparisons between rest vs exercise in endurance-trained and sedentary controls.

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  Fig 3. Left ventricular pressure-volume loop of one endurance-trained at rest (blue) and during exercise (red). Dashed lines indicate the slopes of Emax and EA. Note that Emax increases (increased slope) from rest to exercise, whereas EA decreases (decreased slope), resulting in decrease in ventricular-arterial coupling (left sided displacement of the EA/Emax intercept). Stroke work (i.e. the area within the pressure-volume loop) increases from rest to exercise and ventricular efficiency (i.e. the area within the pressure-volume loop divided by the total pressure-volume area) increases from rest to exercise. EA: arterial elastance; Emax: maximal ventricular elastance; LV: left ventricular.

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  Fig 4. Change of left ventricular stroke work (SW; panel A), potential energy (PE; panel B), ventricular efficiency (VE; panel C), and energy per ejected volume (EEV; panel D) from rest to exercise. Endurance-trained (ET) and sedentary controls (SC) did not differ in SW, PE, VE, or EEV at neither rest nor during moderate exercise, and there were no differences in delta values (exercise minus rest) of SW, PE, VE, or EEV between groups. Individual values are plotted and error bars denote median [IQR]. P-values indicate Wilcoxon signed-rank test comparisons between rest vs exercise in ET and SC.

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  Fig 5. Change of arterial elastance (EA; panel A), maximal ventricular elastance (Emax; panel B), and ventricular-arterial coupling (EA/Emax; panel C) from rest to exercise. Endurance-trained subjects (ET) and sedentary controls (SC) had similar responses in EA, Emax, and ventricular-arterial coupling to exercise. Individual values are plotted, and error bars denote median [IQR]. P-values indicate Wilcoxon signed-rank test comparisons between rest vs exercise in ET and SC.

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  Fig 6. Bland-Altman plots of intraobserver variability. Differences between measurements of cardiac magnetic resonance imaging variables and pressure-volume loops parameters during exercise from the same observer across two different time points against the average. Mean of the differences between measurements (bias) and limits of agreement (± 1.96 SD) are marked.

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  Fig 7. Bland-Altman plots of interobserver variability. Differences between observations of cardiac magnetic resonance imaging variables and pressure-volume loops parameters during exercise against the average. Mean of the differences between observers (bias) and limits of agreement (± 1.96 SD) are marked.