Cardiac Findings in Swimming-Induced Pulmonary Edema: Implications for Acute Assessment

Pathologic cardiac findings have been described in case reports of patients with swimming-induced pulmonary edema (SIPE).

What are the cardiac findings in patients with SIPE and how are they characterized?

A cohort study evaluated patients with SIPE and asymptomatic swimmers (control participants) participating in Sweden's largest open-water swimming event, Vansbrosimningen, from 2022 through 2024. Transthoracic echocardiogram (TTE), ECG, and cardiac biomarkers were assessed within 2 hours following swimming and at follow-up within 12 months.

In total, 45 patients with SIPE and 45 control participants were included in the study. Systolic ventricular function on TTE was mildly impaired following swimming in 43% of patients and 10% of control participants (P = .003). Systolic pulmonary artery pressure was increased in 30% of patients but in none of the control participants (P = .005). TTE pathology had improved at follow-up in all but 1 patient. Findings on ECG following swimming showed no difference between groups (P = .746). High-sensitivity cardiac troponin I levels following swimming were increased in 67% of patients and 40% of control participants (median, 47 pg/mL vs 14 pg/mL; P < .001). N-terminal pro-B-type natriuretic peptide levels were higher in patients than in control participants (median, 169 pg/mL vs 65 pg/mL; P < .001). Two patients with myocardial infarction concurrently with SIPE had clinically significant chest pain and high levels of cardiac troponin.

In patients with SIPE, transient mildly affected cardiac function on TTE and a small to moderate elevation of cardiac biomarkers is likely to be found. ECG did not differ between groups. This study provides a reference of expected cardiac findings in patients with SIPE.

ClinicalTrials.gov; No.: NCT05391737; URL: www.

gov.