Integration of longitudinal and circumferential strain predicts volumetric change across the cardiac cycle and differentiates patients along the heart failure continuum

Figures

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  Fig. 1. Left ventricular ejection fraction (EF) can be calculated by integrating peak longitudinal (LS) and circumferential strain (CS), with changes in ventricular volume being linearly related to changes in chamber length and quadratically related to changes in chamber circumference (A).[15] In a randomly chosen sample of 79 individuals with varying EF and clinical status, EF calculated using the integrated strain approach (EFStrain) and EF measured using the gold-standard method of disks volume-time relationship (EFVolume) were strongly related (B), with good agreement between the two measures across a range of EF (C)

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  Fig. 2. Data from a representative individual showing the circumferential and longitudinal strain rate curves as well as how using the integrated strain approach can be used to calculate the volumetric rate of change curve (A). From the integrated strain curve, peak ejection rate (PERStrain) and peak filling rate (PFRStrain) can be identified. PERStrain, calculated using the integrated strain approach and peak ejection rate measured using the gold-standard volume-time relationship (PERVolume) was correlated with good agreement between the two measures across a range of ventricular systolic performance (B). Similarly, PFRStrain calculated using the integrated strain approach and peak filling rate measured using the gold-standard volume-time relationship (PFRVolume) was correlated with good agreement between the two measures in participants with varying degrees of diastolic dysfunction (C). These data were generated using the same randomly chosen sample of 79 individuals as in Fig. 1. s’ – peak systolic strain rate; e’ – peak early diastolic strain rate; a’ – peak late diastolic strain rate

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  Fig. 3. When applied to the entire cohort of subjects (n = 229), the integrated strain approach for measuring left ventricular ejection fraction (EFStrain), peak ejection rate (PERStrain) and peak filling rate (PFRStrain) successfully differentiated groups according to their heart failure diagnosis (all P < 0.01, Panels A–C). *indicates significantly different from control; #indicates significantly different from At-Risk. †indicates significantly different from HFpEF

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  Fig. 4. Three representative case examples are shown, highlighting the strain-volume relationship and the influence each individual strain component has on left ventricular ejection fraction (EF). Top: 63-year-old male with heart failure with preserved EF. Middle: 55-year-old female control participant. Bottom: 80-year-old female with heart failure with reduced EF. Note how a reduction in strain in one direction can be compensated for by a higher strain in the other direction to achieve the same EF, while reductions in both strain components ultimately leads to a reduction in EF. Together, these examples highlight the potential advantages of integrating discrete strain components when interpreting global left ventricular function. Green arrows and numbers represent normal strains, while red arrows and numbers represent impaired strains, relative to the mean of the control group (LS: − 21.5 ± 3.3%; CS: − 29.6 ± 3.9%; EF: 62.0 ± 6.2%)