The rupture risk triad: a novel cardiac magnetic resonance-based predictor of impending heart rupture after STEMI

Background Heart rupture is a rare but life-threatening complication of acute myocardial infarction (AMI). While acute rupture leads to cardiac tamponade and sudden death, subacute forms may allow for early detection and treatment. Cardiac magnetic resonance (CMR) is the gold standard for non-invasive assessment of microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH), key mechanisms contributing to infarcted tissue weakening and rupture risk. However, the role of CMR in identifying impending heart rupture (IHR) is underexplored. Purpose To identify CMR imaging features associated with IHR. Methods CMR examinations performed within the first week from ST-elevation MI (STEMI) in patients from January 2018 to November 2024 were retrospectively evaluated. IHR was defined by the presence of transmural MVO, extra-myocardial thrombosis, pseudoaneurysm, or post-infarction septal defect. Results A total of 205 patients were included, 88% were male and 62% had an anteroseptal infarction. IHR was identified in 26 patients (12%). Compared to patients without IHR, these individuals were all experiencing their first MI (0% vs 31%, p = 0.02) and had lower LVEF% (38% vs 49%, p = 0.002), higher LV mass (88 vs 75 g/m², p = 0.003), greater infarcted wall thickness (15 vs 10 mm, p < 0.001), and a higher infarcted-to-remote wall thickness ratio (1.44 vs 1.09, p < 0.001). The prevalence of MVO and IMH was significantly higher among patients with IHR, occurring in 100% of cases compared to 39% (p < 0.001) and 26% (p < 0.001) in the non-rupture group, respectively. Also, LV thrombus and pericardial effusion were more frequent in patients with IHR (48% vs 13%, p < 0.001 and 88% vs 15%, p < 0.001, respectively). On univariate analysis, infarcted wall thickness (OR 1.57, 95% CI 1.3–1.9, p < 0.001), the presence of MVO (OR 38, 95% CI 5.1–293, p < 0.001), LV thrombus (OR 45, 95% CI 13–161, p < 0.001), lower LVEF% (OR 0.97, 95% CI 0.95–0.99, p = 0.015), and infarcted-to-remote wall thickness ratio > 1 (OR 1.4, 95% CI 1.25–1.63, p < 0.001) were all predictors of IHR. The presence of the "Rupture Risk Triad", characterized by a combination of pericardial effusion, infarcted wall thickness > 12 mm, and an infarcted-to-remote wall thickness ratio > 1 had the highest predictive value (OR 371, 95% CI 68–2036, p < 0.001). On multivariate analysis, only MVO (OR 27, 95% CI 1.7–416, p = 0.02) and the Rupture Risk Triad (OR 263, 95% CI 28–2512, p < 0.001) remained independent predictors of IHR. Conclusions CMR plays a crucial role in the early identification of IHR following STEMI. In our retrospective study, the identification of the Rupture Risk Triad, represented by a combination of pericardial effusion, infarcted wall thickness > 12 mm, and infarcted-to-remote wall thickness ratio > 1 emerged as a strong and independent predictor of IHR, with a sensitivity of 81% and a specificity of 99%.