# Longitudinal observation of left ventricular inflow reorientation with preserved vorticity after myocardial infarction in a porcine model

## TL;DR

This study tracks heart flow changes in pigs after a heart attack, finding that while heart structure changes, certain flow patterns remain stable.

## Contribution

The study provides longitudinal in vivo data on intracardiac flow dynamics after myocardial infarction in a porcine model.

## Key findings

- Both animals showed consistent LV remodeling patterns after MI, including wall thinning and volume increases.
- Intracardiac vorticity remained preserved despite structural changes.
- The angle of the helical filling vortex increased over time, suggesting potential as a remodeling marker.

## Abstract

The evolution of left ventricular (LV) intracardiac flow characteristics following myocardial infarction (MI), and their relationship to LV remodeling, remains incompletely understood, particularly from longitudinal in vivo observations with dense temporal sampling.

Two porcine models with experimentally induced myocardial infarction at the left anterior descending artery were longitudinally followed from baseline to 11 weeks, with 10 cardiac MRI sessions per animal. Cardiac MRI assessed myocardial tissue characteristics (LGE, native T1/T2 mapping, and extracellular volume), global left ventricular function, and strain. Four-dimensional flow MRI was used to characterize intracardiac flow features, including E/A ratio, vorticity, and diastolic helical vortex structures. Longitudinal changes were examined descriptively within each animal. Overall temporal trends were summarized using the Theil–Sen estimator, with uncertainty assessed by residual bootstrap-derived 95% confidence intervals.

Both animals demonstrated overall remodeling patterns consistent with post-infarction progression, including temporal reductions in LGE with secondary changes during the chronic phase, thinning of the infarcted myocardial wall, and increases in indexed end-diastolic and end-systolic volumes. Native T1 relaxation time increased over time in one animal and showed a similar directional pattern in the other. Despite these structural and tissue-level changes, regional intracardiac vorticity remained relatively preserved throughout the study period. In contrast, the angle of the helical filling vortex between the anatomical LV and the vortex core centerlines was observed to increase in both animals.

In this exploratory longitudinal study, both animals demonstrated similar temporal patterns of LV remodeling after MI, despite differences in the absolute magnitude of the measured parameters. In addition, our findings suggest that the angle of the helical filling vortex may have potential as a remodeling marker, which warrants validation in larger cohorts.