The value of the left atrium as detected by cardiovascular magnetic resonance in predicting reverse left ventricular remodeling in patients with ST-segment elevation myocardial infarction.

BACKGROUND

The importance of the left ventricle after ST-segment elevation myocardial infarction (STEMI) has been well established; however, the role of left atrial (LA) dynamics in reverse left ventricular remodeling (R-LVR) remains unclear. This study aimed to assess structural and functional changes in the left heart by serial cardiovascular magnetic resonance (CMR) imaging, exploring the predictive value of the left atrium and left ventricle for R-LVR.

METHODS

A total of 105 patients with STEMI were retrospectively enrolled in the study, and data on their baseline clinical characteristics and CMR features at 4 days and 5 months after percutaneous coronary intervention (PCI) were collected. The CMR evaluation included the LA and left ventricular (LV) volumes, myocardial function, and infarct characteristics. The patients were categorized into two groups according to the presence of R-LVR, which was assessed by comparing the two CMR examinations; 47 patients were assigned to the R-LVR group, and 58 to the non-R-LVR group. Subsequently, the baseline clinical and CMR characteristics of these two groups were compared. The R-LVR predictors were identified by logistic regression. Three predictive models were built to explore the incremental value of the left heart function parameters for R-LVR prediction, using the Net Reclassification Index (NRI).

RESULTS

At first CMR, the R-LVR group had higher LV and LA volumes, and LV longitudinal displacement, as well as a lower myocardial injury value and LA reservoir strain rate (all P<0.05). At the second CMR, the R-LVR group had a lower LV volume, a smaller infarct mass, and greater left ventricular ejection fraction (LVEF) (all P<0.05). Notably, the left ventricular end-diastolic volume (LVEDV) [odds ratio (OR): 1.022, 95% confidence interval (CI): 1.007-1.037, P=0.005], infarct mass (OR: 0.946, 95% CI: 0.918-0.975, P<0.001), and LA reservoir strain rate (OR: 0.224, 95% CI: 0.055-0.905, P=0.036) were independent predictors of R-LVR. When LV longitudinal displacement and the LA reservoir strain rate were introduced into the model, the NRI was 44.10%.

CONCLUSIONS

This study assessed the predictive value of the LVEDV, infarct mass, and LA reservoir strain rate by CMR, and found that the combination of the LA reservoir strain rate and LV longitudinal displacement improved model prediction of R-LVR.