Acute Myocarditis Riskier Than Unexplained Chest Pain

TOPLINE: 

Despite being younger and having fewer comorbidities, patients with acute myocarditis (AM) had a significantly higher risk for 30-day and long-term mortality than those with unexplained chest pain.

METHODOLOGY: 

• The accurate differentiation of AM from unexplained chest pain is a significant clinical challenge.
• Researchers conducted a retrospective analysis of data from a Swedish registry to compare the short- and long-term outcomes of AM with those of unexplained chest pain.
• They included patients older than 16 years who were hospitalised between 1998 and 2018 and had a diagnosis of either AM (n = 3792; median age, 37 years; 79.9% men) or unexplained chest pain (n = 109,934; median age, 59 years; 51.4% men).
• The primary outcome was all-cause mortality at 30 days and at a long-term follow-up (median follow-up duration, 7.8 years).
• Further assessments included the risk for myocardial infarction (MI), development of heart failure, significant bleeding, and stroke.

TAKEAWAY:

• Patients with AM were younger (P < .001) and had fewer comorbidities than those with unexplained chest pain. Chest pain was the most common presenting symptom in patients with AM (82.9%) and those with unexplained chest pain (93.4%).
• Although rare overall, cardiac shock and resuscitated cardiac arrest occurred more frequently in the AM group than in the unexplained chest pain group.
• Mortality at 30 days (adjusted odds ratio [aOR], 3.75; P < .001) and the risk of developing heart failure during hospitalisation (aOR, 5.4; P < .001) were significantly higher in patients with AM than in those with unexplained chest pain.
• Long-term risks for mortality, heart failure, and MI were higher in patients with AM than in those with unexplained chest pain (P < .001 for all).

IN PRACTICE:

“[The study] findings challenge the common perception of AM as a benign condition and emphasise the need for structured follow-up for these patients over both the short term and long term,” the authors wrote.

SOURCE: 

This study was led by Marie Björkenstam, MD, Sahlgrenska University Hospital, Gothenburg, Sweden. It was published online on April 04, 2025, in Open Heart.

LIMITATIONS:

Despite rigorous validation of the registry, a risk of reporting inaccurate data remained. Misclassification may have occurred owing to significant challenges in differentiating AM from unexplained chest pain. Furthermore, the true incidence of hospitalisations related to AM may have been underestimated, given the complexity of its diagnosis.

DISCLOSURES: 

This study was supported by grants from the Gothenburg Society of Medicine and the Swedish state under the agreement between the Swedish government and the county councils. The authors declared having no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.