# Mechanical wave velocities in acute myocardial infarction: an exploratory study using three-dimensional high frame rate echocardiography

## TL;DR

This study explores using high-speed 3D echocardiography to measure mechanical wave speeds in heart attack patients, finding higher speeds in damaged areas compared to healthy ones.

## Contribution

Demonstrates the feasibility of 3D high frame rate echocardiography for measuring mechanical wave velocities in acute myocardial infarction patients.

## Key findings

- Global mechanical wave velocities were significantly higher in AMI patients than in controls.
- Infarcted territories showed higher velocities compared to corresponding healthy territories.
- Mechanical wave velocities correlated strongly with wall motion score index and were higher in segments with wall motion abnormalities.

## Abstract

High frame rate (HFR) echocardiography captures myocardial mechanical waves (MWs), reflecting critical tissue properties. The aim was to assess the feasibility of 3D HFR echocardiography for estimating MW velocities in acute myocardial infarction (AMI) patients and to compare MW velocities with those in controls.

Twenty patients with ST-elevation AMI were included within 48 h of reperfusion therapy. 3D high-quality recordings (∼20 volumes/s) were acquired for myocardial segmentation and 3D HFR recordings (750 volumes/s) for measuring the atrial kick wave propagation velocity. MW velocities were compared with 20 controls. MW velocities were successfully measured in 93% of subjects (17 patients and 20 controls). The segmental feasibility was 97%. Global MW velocities were significantly higher in AMI patients than controls (2.1 ± 0.6 m/s vs. 1.5 ± 0.2 m/s, P < 0.001). Infarcted territories had higher velocities when compared with the corresponding territories in controls: right coronary artery: 1.9 ± 0.7 m/s vs. 1.4 ± 0.3 m/s, P < 0.05; circumflex artery: 3.1 ± 1.5 m/s vs. 1.7 ± 0.4 m/s, P < 0.01; and left anterior descending artery: 1.8 ± 0.5 m/s vs. 1.4 ± 0.2 m/s, P < 0.01. There was a strong correlation between global MW velocities and wall motion score index (r = 0.70, P < 0.001). MW velocities were higher in segments with wall motion abnormalities than in healthy segments (2.3 ± 1.1 vs. 1.6 ± 0.7 m/s, P < 0.001).

Estimation of MW velocities using 3D HFR echocardiography had excellent feasibility. MW velocities were higher in patients with AMI than in controls, in infarcted compared with healthy territories, and in segments with wall motion abnormalities. Future work should evaluate the clinical value in larger populations.

Graphical AbstractFeasibility and velocity estimation using 3D high frame rate mechanical wave imaging in patients with ST-elevation myocardial infarction. STEMI, ST-elevation myocardial infarction.

Feasibility and velocity estimation using 3D high frame rate mechanical wave imaging in patients with ST-elevation myocardial infarction. STEMI, ST-elevation myocardial infarction.