Quantification of Myocardial Contraction Fraction with Three-Dimensional Automated, Machine-Learning-Based Left-Heart-Chamber Metrics: Diagnostic Utility in Hypertrophic Phenotypes and Normal Ejection Fraction

Figures

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  Figure 1. Flowchart depicting the patient selection process. * Absence of diabetes, hypertension, previous or current heart disease, cardiac implantable electronic devices, stroke, chronic obstructive pulmonary disease, venous thromboembolism, cancer, previous or current systemic diseases that may have an impact on the cardiovascular system, drug therapy, or other treatments with cardiovascular effects, normal cardiovascular physical examination, normal ECG at rest) without clinical indication of DHM. 2DE: bidimensional echocardiography; DHM: Dynamic Heart Model; LVEF: left ventricular ejection fraction; VHD: valvular heart disease; BMI: body mass index; IHT: isolated arterial hypertension; HCM: hypertrophic cardiomyopathy; CA: cardiac amyloidosis.

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  Figure 2. Myocardial contraction fraction values across patients’ subgroups CA, cardiac amyloidosis; HCM, hypertrophic cardiomyopathy; IHT, isolated hypertension; MCF, myocardial contraction fraction.

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  Figure 3. Performance of myocardial contraction fraction for detecting hypertrophic phenotypes. (Panel A) Receiver-operating characteristics (ROC) curve showing the performance of myocardial contraction fraction for detecting hypertrophic cardiomyopathy. (Panel B) ROC curve showing the performance of myocardial contraction fraction for detecting Cardiac amyloidosis. (Panel C) ROC curve showing the performance of myocardial contraction fraction for detecting isolated hypertension. AUC, area under the curve; CA, cardiac amyloidosis; HCM, hypertrophic cardiomyopathy; IHT, isolated hypertension.

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  Figure 4. Example of 3D measurements (LV volumes and LV mass) obtained from automated DHM in a patient with cardiac amyloidosis and normal EF (54%). This advanced echocardiography allows for accurate, automated measurements of chamber volumes and function providing larger, more accurate LV volumes with good agreement with cardiac magnetic resonance when analyzed using the default settings of the boundary detection sliders (end-diastolic default position = 60/60; end-systolic default position = 30/30). LV myocardial mass (233 g) divided by the mean density of myocardium of 1.05 g/mL presents LV myocardial volume (221 mL). The ratio of SV (88 mL) to myocardial volume calculated the Myocardial Contraction Fraction (39%), significantly lower than the EF. LV: left ventricular; DHM: Dynamic Heart Model, Philips Healthcare, Andover, MA, USA; SV: stroke volume; EF: ejection fraction. DHM automatically measures chamber volumes throughout the cardiac cycle, resulting in LV time curve (yellow).