Cardiac Manifestations of Mycoplasma pneumoniae Infections: A Cohort Study 2007–2024

Background. While Mycoplasma pneumoniae (MP) infections typically present as a respiratory disease, extrapulmonary manifestations are well-documented. Historically, cardiac involvement has been considered uncommon (1%–2%); however, recent observations suggest higher rates, especially in MP ICU patients. This study aims to characterize the prevalence, clinical spectrum, and outcomes of hospitalized patients with MP and cardiac manifestations. Methods. We conducted a cohort study at Hadassah Medical Center, Jerusalem, Israel, including all inpatients with a positive PCR for MP from 2007 to mid-2024. Cardiac involvement included congestive heart failure (CHF), arrhythmias, acute coronary syndrome (ACS), peri/myocarditis, and isolated troponin elevation. Results. Of 1305 MP-positive patients (mean age 33.4 years), 152 (11.6%) were found to have cardiac involvement—17% among adult patients and 4.9% among children (P <.001). In adults, CHF and arrhythmias were most common (each 34.7%), followed by ACS (10.5%), peri/myocarditis (15.3%), and isolated troponinemia (9.7%). ICU admission occurred in 50% of adults with cardiac involvement and was significantly higher in arrhythmias and peri/myocarditis groups. In-hospital mortality among adults was high at 22.6%. Predictors of mortality included ICU admission (aOR 7.76; CI: 2.78–21.66), older age (aOR per year increase: 1.03; CI: 1.01–1.06), and primary diagnosis other than MP (aOR 3.57; CI: 1.34–9.51). Pediatric cardiac involvement primarily presented as arrhythmia (42.9%). Conclusions. Cardiac involvement in hospitalized MP-infected adults is more common than previously recognized (17%) and carries substantial morbidity and mortality risks. Early evaluation for cardiac complications is crucial in MP-infected hospitalized patients presenting with severe illness or unexplained cardiac symptoms.