Abstract Body (Do not enter title and authors here):

Introduction
Mechanical complications after acute myocardial infarction (MI) have decreased in the context of readily available pPCI and other reperfusion therapies, however, many patients still cannot achieve adequate reperfusion status. Acute Mitral Regurgitation (AMR) is associated with worse clinical outcomes, and can be classified according to three main mechanisms; papillary muscle ischemia, papillary muscle rupture and left ventricular remodeling.
Data regarding AMR an association between disease mechanism and mortality is lacking.

Objective
To assess the association between AMR mechanism and mortality

Methods
We performed a retrospective cohort study and included patients who visited the ED in a Mexican National Institute due to ACS who also presented AMR from February 2006 through to October 2023.
A univariate Cox regression model was performed and adjusted by age and sex, and the only Killip-Kimball class (K-K) and Type of ACS at admission showed significance, which both persisted in individual adjusted multivariate analyses. A survival analysis with Kaplan-Meier curve was done.

Results
We included 161 patients in the analysis. The frequency per AMR mechanism was 98 (60.4%) for ischemia of papillary muscle, 33 (20.3%) for papillary muscle rupture, and 30 (19.3%) for left ventricular remodeling.
The multivariate Cox regression models were done by subgroup analysis, by each different type of AMR mechanism. Ischemia of Papillary Muscle showed a significantly increased risk for mortality when analyzed by K-K (HR 1.48, 95% CI 1.01-2.17, p=0.045), but showed a decreased risk by ACS type (HR 0.39, 95% CI 0.18-0.82, p=0.014). Papillary Muscle Rupture was associated with increased risk for mortality in the model with K-K (HR 1.8, 95% CI 0.95-3.38, p=0.067) but not by ACS type. Left Ventricular Remodelling was not significantly associated with an increased risk in any model.

Conclusions
In patients presenting AMR and ACS, there was an increased risk of mortality in the subgroup of patients with ischemic mitral regurgitation.