Non‐invasive pressure–volume loop analysis in left ventricular load manipulation

Figures

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  Figure 1. Study overview and PV‐loop parameters. Top: Two sets of experiments were performed to assess the effects of preload and afterload alteration on non‐invasive pressure–volume (PV) loops. (1) Controls and patients with HCM were studied at rest and during infusion of isotonic saline. (2) Volunteers were studied at rest and during infusion of glyceryl trinitrate. Bottom: From the PV‐loops, we computed contractility and arterial elastance as the respective slope of the dashed lines, as well as ventricular‐arterial coupling as the ratio of arterial elastance/contractility, stroke work as the area of the loop, potential energy as the area of the blue triangle, and ventricular efficiency according to the formula in the figure. E max, maximum elastance; HCM, hypertrophic cardiomyopathy.

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  Figure 2. Average pressure–volume loops with alterations in preload and afterload. Each pressure–volume loop is computed from the average values in the respective cohort at a given hemodynamic state. Controls and patients with HCM were examined at baseline and during saline infusion, while another group of volunteers was examined at baseline and during infusion of GTN. GTN, glyceryl trinitrate; HCM, hypertrophic cardiomyopathy.

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  Figure 3. Effects of saline infusion on pressure–volume loop parameters. Left ventricular contractility, arterial elastance, ventricular‐arterial coupling, stroke work, potential energy and ventricular efficiency, measured in controls (black) and patients with hypertrophic cardiomyopathy (HCM) (red) at baseline and during saline infusion. The Wilcoxon test was used for paired intragroup comparisons, and p values show paired comparisons within each group.

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  Figure 4. Associations between changes in contractility, arterial elastance and ventricular‐arterial coupling (E a/E max ratio) and volumetric or pressure response to saline infusion in controls (black) and patients with HCM (red). E a, arterial elastance; E max, maximum elastance; EDV, end‐diastolic volume; EF, ejection fraction; HCM, hypertrophic cardiomyopathy; SBP, systolic blood pressure.

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  Figure 5. Associations between changes in stroke work, potential energy and ventricular efficiency and volumetric or pressure response to saline infusion in controls (black) and patients with HCM (red). EDV, end‐diastolic volume; EF, ejection fraction; ESV, end‐systolic volume; HCM, hypertrophic cardiomyopathy.

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  Figure 6. Effects of glyceryl trinitrate (GTN) infusion on pressure–volume loop parameters. Left ventricular contractility, arterial elastance, ventricular‐arterial coupling, stroke work, potential energy and ventricular efficiency, measured in volunteers at baseline and during GTN infusion. The Wilcoxon test was used for paired intragroup comparisons.

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  Figure 7. Associations between changes in contractility, arterial elastance and ventricular‐arterial coupling (E a/E max ratio) and volumetric or pressure response to glyceryl trinitrate infusion in volunteers. E a, arterial elastance; E max, maximum elastance; EDV, end‐diastolic volume; EF, ejection fraction; SBP, systolic blood pressure.

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  Figure 8. Associations between changes in stroke work, potential energy and ventricular efficiency and volumetric or pressure response to glyceryl trinitrate infusion in volunteers. EDV, end‐diastolic volume; EF, ejection fraction; ESV, end‐systolic volume.