Computational Analysis of Cardiac Contractile Function

Abstract

Purpose of review: Heart failure results in the high incidence and mortality all over the world. Mechanical properties of myocardium are critical determinants of cardiac function, with regional variations in myocardial contractility demonstrated within infarcted ventricles. Quantitative assessment of cardiac contractile function is therefore critical to identify myocardial infarction for the early diagnosis and therapeutic intervention.

Recent findings: Current advancement of cardiac functional assessments is in pace with the development of imaging techniques. The methods tailored to advanced imaging have been widely used in cardiac magnetic resonance, echocardiography, and optical microscopy. In this review, we introduce fundamental concepts and applications of representative methods for each imaging modality used in both fundamental research and clinical investigations. All these methods have been designed or developed to quantify time-dependent 2-dimensional (2D) or 3D cardiac mechanics, holding great potential to unravel global or regional myocardial deformation and contractile function from end-systole to end-diastole. Computational methods to assess cardiac contractile function provide a quantitative insight into the analysis of myocardial mechanics during cardiac development, injury, and remodeling.

Keywords: Biomedical imaging; Cardiac contractile function; Computational analysis; Heart failure.

Figure 1.

Schematic diagram of myocardial strain. A. Three types of strain are defined along longitudinal, circumferential, and radial, respectively. B-C. Circumferential and radial strains are obtained from short-axis sections, whereas longitudinal strain is obtained from long-axis sections. Cd: circumferential strain in diastole, Cs: circumferential strain in systole, Ld: longitudinal strain in diastole, Ls: longitudinal strain in systole, Rd: radial strain in diastole, Rs: radial strain in systole. In the long-axis plane, the longitudinal deformation corresponds to apex-base shortening / lengthening. In the short-axis plane, circumferential strain is tangential to the epicardial wall (oriented along the perimeter), and radial strain is oriented toward the center of the ventricular cavity. Ventricular sections close to the apex have a counterclockwise systolic rotation, whereas sections close to the base have a clockwise rotation.

Figure 2.

A. Implemented tagging lines are orthogonal to the imaging slice in conventional CMR tagging methods. B. In contrast, the tag planes generated in SENC are parallel to and inside the imaging slice, to record through-plane strain.

Figure 3.

The advent of methods for cardiac magnetic resonance and echocardiography. Adapted from references: [19], [42], [47], [111], [112].

Figure 4.

A. Auto-correlation-based tissue Doppler imaging (TDI). B. Cross-correlation based 2D speckle tracking (STE). Vt: Velocity towards the transducer. Va: velocity away from the transducer. VL: Longitudinal velocity along the myocardial contraction. VT: Transverse velocity perpendicular to myocardial contraction.

Figure 5.

A. Fundamental concept of the light-sheet imaging strategy. B. Displacement analysis of focal myocardial mechanical deformation (DIAMOND) in zebrafish embryos. (Adapted with permission from: Chen et al. [77].)