BackgroundThe tricuspid annular plane systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio is a non-invasive surrogate for right ventricular–pulmonary arterial (RV-PA) coupling, studied in chronic RV pressure overload syndromes. However, its prognostic utility in patients with acute myocardial infarction (AMI), which may cause acute RV pressure overload, remains unexplored. ObjectiveThis study aimed to determine predictors of RV-PA uncoupling in patients with first AMI and examine whether it could improve risk stratification for cardiovascular in-hospital mortality after revascularization. MethodsThree-hundred consecutive patients with first AMI were prospectively studied (age 61.2 ± 11.8, 24% females). Echocardiography was performed 24 h after successful revascularization, and TAPSE/PASP was evaluated. Cardiovascular in-hospital mortality was recorded. ResultsThe optimal cutoff value of TAPSE/PASP to determine cardiovascular in-hospital mortality was 0.49 mm/mmHg. RV-PA uncoupling was considered for patients with TAPSE/PASP ≤0.49 mm/mmHg. Left ventricular ejection fraction (LVEF) was independently associated with RV-PA uncoupling. A total of 23 (7.7%) patients died in hospital despite successful revascularization. TAPSE/PASP was independently associated with in-hospital mortality after adjustment for Global Registry of Acute Coronary Events (GRACE) risk score and LVEF (odds ratio 0.14 [95% confidence interval 0.03–0.56], P = 0.007). The prognostic value of a baseline model including the GRACE risk score and NT-pro-BNP (χ2 26.55) was significantly improved by adding LVEF ≤40% (χ2 44.71, P < 0.001), TAPSE ≤ 17 mm (χ2 75.42, P < 0.001) and TAPSE/PASP ≤ 0.49 mm/mmHg (χ2 101.74, P < 0.001) for predicting cardiovascular in-hospital mortality. ConclusionRV-PA uncoupling, assessed by echocardiographic TAPSE/PASP ≤ 0.49 mm/mmHg 24 h after revascularization, may improve risk stratification for cardiovascular in-hospital mortality after first AMI.