Cardiac rupture complicating acute myocardial infarction: the clinical features from an observational study and animal experiment

Background. Cardiac rupture (CR) is a fatal complication of ST-elevation myocardial infarction (STEMI) with its incidence markedly declined in the recent decades. However, clinical features of CR patients now and the effect of reperfusion therapy to CR remain unclear. We investigated the clinical features of CR in STEMI patients and the effect of reperfusion therapy to CR in mice. Methods. Two studies were conducted. In Study 1, Data of 1456 STEMI patients admitted to the First Hospital, Xi'an Jiaotong University during 2015.12.~2018.12. were analyzed. In Study 2, 83 male C57BL/6 mice were operated to MI, 39 mice were allocated for MI (group-1) and 21 mice for 1 h (group-2 ) and 23 mice for 4 h (group-3) ischemia followed by reperfusion. All operated mice were monitored up to day-10. Animals were inspected three times daily for the incidence of death and autopsy was done for all mice found died to determine the cause of death. Results. CR was diagnosed in 40 patients: free-wall rupture in 17, ventricular septal rupture in 20, and combined locations in 3 cases, present in 19 patients at admission and diagnosed in another 21 patients during 1 ~ 14 days post-STEMI, giving an in-hospital incidence of 1.4%. The mortality of CR patients was high during hospitalization accounting for 39% of total in-hospital death. By multivariate logistic regression analysis, older age, peak CK-MB and peak hs-CRP were independent predictors of CR post-STEMI. There were 17 deaths in group-1 during day 3–6 post MI. In the two IR groups, one mouse died of acute heart failure at day-5 post surgery and the rest of mice survived to the end of experiment without onset of rupture. Conclusion. CR remains as a major cause of in-hospital death in STEMI patients. CR Patients are characterized of being elderly, having larger infarct and more server inflammation. Reperfusion therapy can decrease CR incidence sharply.