Estimating prognosis in patients with acute myocardial infarction using personalized computational heart models

Abstract

Biomechanical computational models have potential prognostic utility in patients after an acute ST-segment-elevation myocardial infarction (STEMI). In a proof-of-concept study, we defined two groups (1) an acute STEMI group (n = 6, 83% male, age 54 ± 12 years) complicated by left ventricular (LV) systolic dysfunction; (2) an age- and sex- matched hyper-control group (n = 6, 83% male, age 46 ± 14 years), no prior history of cardiovascular disease and normal systolic blood pressure (SBP < 130 mmHg). Cardiac MRI was performed in the patients (2 days & 6 months post-STEMI) and the volunteers, and biomechanical heart models were synthesized for each subject. The candidate parameters included normalized active tension (AT norm) and active tension at the resting sarcomere length (T req, reflecting required contractility). Myocardial contractility was inversely determined from personalized heart models by matching CMR-imaged LV dynamics. Compared with controls, patients with recent STEMI exhibited increased LV wall active tension when normalized by SBP. We observed a linear relationship between T req 2 days post-MI and global longitudinal strain 6 months later (r = 0.86; p = 0.03). T req may be associated with changes in LV function in the longer term in STEMI patients complicated by LV dysfunction. Further studies seem warranted.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1

Predicted systolic strain from a personalized left ventricular model compared with in vivo measurements in one healthy subject.

Figure 2

Simulated left ventricular dynamics in a healthy control subject and a patient after acute STEMI. (A,B) Deformed left ventricular geometries superimposed in CMR images at end-diastole and end-systole for the healthy control and for the MI patient (C,D). (A–D) are coloured by displacements related to the early-diastole geometry. Red: high, blue: low.

Figure 3

Comparisons between the control groups and the STEMI group in: (A), required contractility; (B) average systolic active tention; (C), systolic blood pressure; and (D), active tension generation per mmHg ventricular pressure increase.

Figure 4

Estimated stiffness along myofibre direction under differnet end-diastolic pressure.

Figure 5

The scatter plots of (A): the global longitudinal strain (GLS) and (B): LVEF change after six months in the STEMI group in related to the required contractility.

Figure 6

An example of the left ventricular model construction for a healthy control: (A), Left ventricular boundary segmentation; (B), reconstructed left ventricular geometry. An example of a diseased left ventricular model construction: (C), left ventricular boundary segmentation; (D), a LGE image in a middle short-axial position, MI region is indicated by the arrows, the black region inside the infarct region represents the microvascular obstruction. (E), a LGE image in a long-axial view; (F), reconstructed left ventricular model, the infart region is represented by the red colour, and the remote viable myocardium is represented by the blue color. A linear transition region is defined from the infart region towards the remote viable myocardium within 10 mm (1: 100% infarction, 0: viable myocardium).