ElectroMechanical Activation Time (EMAT) from wearable synchronous phonocardiogram-electrocardiogram device predicts left ventricular systolic dysfunction and prognosis in acute myocardial infarction

Background & Aims Left ventricular systolic dysfunction (LVSD) and ventricular remodeling after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) are major predictors of long-term adverse cardiovascular events. Current evaluation tools such as B-type natriuretic peptide (BNP) and echocardiography are limited by high cost, professional operation, and insufficient dynamic monitoring. Electromechanical activation time (EMAT, ms) is a non-invasive indicator reflecting left ventricular electromechanical coupling, but its prognostic value in AMI patients after PCI remains unclear. This study aimed to investigate the predictive value of EMAT measured by a wearable synchronous phonocardiogram-electrocardiogram (PCG-ECG) device for LVSD and major adverse cardiovascular events (MACEs) in AMI patients post-PCI. Methods This single-center prospective cohort study enrolled AMI patients undergoing emergency PCI between May 2024 and April 2025. Baseline EMAT was measured by a wearable synchronous PCG-ECG device. Baseline characteristics, comorbidities, medications, laboratory parameters, and left ventricular ejection fraction (LVEF) were collected. Primary endpoints were 6- and 12-month MACEs. Secondary endpoints included all-cause death, unplanned readmission, and LVSD (LVEF <50%). The correlation between EMAT and LVEF was analyzed using smoothing splines. Multivariate Cox regression was performed to evaluate the independent prognostic value of EMAT. Subgroup analysis was conducted according to age. Peri-procedural ΔEMAT was also assessed. P<0.05 was considered statistically significant. Results A total of 375 patients completed 6-month follow-up and 152 completed 12-month follow-up. Baseline EMAT was negatively and linearly correlated with LVEF (Figure 1). With increasing EMAT tertiles, LVEF decreased significantly (52.00–75.00 ms: 56.01%; 76.00–86.00 ms: 53.02%; 87.00–129.00 ms: 51.32%, P<0.001). At 6 months, 78 MACEs occurred; at 12 months, 31 MACEs occurred. In multivariable Cox regression, per 1 Z-score increase in EMAT was associated with higher 12-month MACE risk (HR=2.06, 95%CI:1.39–3.06, P=0.0003). The highest EMAT tertile conferred a 5.72-fold higher MACE risk compared with the lowest tertile (HR=5.72, 95%CI:1.63–20.13, P=0.0065; Table 1). The predictive effect of EMAT was stronger in patients <60 years (P-interaction=0.0053). Peri-procedural ΔEMAT showed no significant prognostic value (P>0.05). Conclusions Prolonged baseline EMAT is an independent predictor of LVSD and MACEs in AMI patients after PCI, especially in those younger than 60 years. The wearable PCG-ECG device provides a non-invasive, convenient, and low-cost strategy for risk stratification. Peri-procedural short-term ΔEMAT has no significant prognostic impact in this population.