Background: Intracardiac thrombus is a clinically important complication of acute myocardial infarction (AMI), particularly in patients with ventricular aneurysm. We examined the contemporaneous associations of anterior ventricular involvement and D-dimer with echocardiographically documented intracardiac thrombus with incomplete chamber-specific localization among hospitalized AMI patients with ventricular aneurysm. Methods: This retrospective analysis included 1684 patients with documented ventricular aneurysm from a final cohort of 17,950 hospitalized AMI patients treated between January 2018 and October 2025. The first D-dimer measurement obtained at our hospital after AMI confirmation was used for D-dimer analyses. Ventricular aneurysm and intracardiac thrombus status were determined from the available echocardiographic documentation during the index hospitalization. Aneurysm locations were coded as linked patient-level, non-mutually exclusive indicators. Logistic regression evaluated anterior involvement; missing model covariates were multiply imputed and regression estimates were pooled using Rubin’s rules. Collinearity diagnostics and sensitivity analyses restricted to patients with apical aneurysm, including a complete-case analysis, were performed. Model-performance measures were interpreted as exploratory apparent performance in the development dataset. Results: Intracardiac thrombus was documented in 211 of 1684 patients (12.5%). Anterior involvement was more frequent among patients with thrombus than among those without thrombus (57.3% vs. 45.0%; p < 0.001) and remained associated with thrombus in the primary anatomical and clinical model (OR, 1.63; 95% CI, 1.20–2.21; p = 0.002). D-dimer was available in 1633 patients. On the log2-transformed scale, each doubling of D-dimer was associated with higher odds of echocardiographically documented intracardiac thrombus (adjusted OR, 1.24; 95% CI, 1.14–1.34; p < 0.001). As a complementary descriptive analysis, the observed thrombus proportion increased from 3.63% in Q1 to 22.30% in Q4; compared with Q1, the adjusted ORs were 3.71, 5.22, and 9.50 in Q2, Q3, and Q4, respectively. The combined model had a mean apparent AUC of 0.716, compared with 0.713 for the model containing D-dimer without anterior involvement; the mean absolute increment was approximately 0.003. Conclusions: Among hospitalized patients with AMI and ventricular aneurysm, higher D-dimer levels and anterior ventricular involvement were associated with echocardiographically documented intracardiac thrombus. Chamber-specific localization was incomplete, and these contemporaneous associations do not establish causality or prospective prediction. Anterior involvement provided minimal incremental discrimination beyond D-dimer.

Background/Objectives: Intracardiac thrombosis (ICT) is a serious complication in acute myocardial infarction (AMI) patients. This study aimed to identify potential risk factors of ICT in AMI patients, providing valuable insights for clinical management. Methods: A case–control study was conducted involving consecutive AMI patients admitted to the First Affiliated Hospital of Xi’an Jiaotong University between January 2019 and December 2022. Binary logistic regression identified independent risk factors of ICT and a nomogram prediction model was constructed and validated for accuracy. Conclusions: A total of 7341 patients with ICT and 74 without ICT were included. Multivariate logistic regression identified male gender, acute anterior wall myocardial infarction (AWMI), ventricular aneurysm, and lower prothrombin activity as independent risk factors of ICT in AMI patients. A nomogram based on these factors demonstrated excellent performance (AUC: 0.910, 95% CI: 0.877–0.943, p < 0.001), with calibration and sensitivity analyses confirming its robustness. This nomogram provides an accurate tool for predicting ICT risk, facilitating personalized management and early intervention in AMI patients.