Insights Into the Natural History of Recurrent Myocarditis, A Multicenter International Study (Re-Myo Study)

Area of Science:

• Cardiology
• Cardiovascular Research
• Clinical Medicine

Background:

• Recurrence of acute myocarditis (AM) poses significant clinical challenges.
• The natural history and management of recurrent AM (Re-AM) are not well-defined.
• This study aims to characterize Re-AM patients' clinical features and outcomes.

Purpose of the Study:

• To investigate the clinical characteristics of patients experiencing recurrent acute myocarditis (Re-AM).
• To compare the outcomes of Re-AM patients with those of single acute myocarditis (S-AM).
• To identify factors associated with an increased risk of recurrent AM.

Main Methods:

• An international multicenter study involving 141 patients with biopsy-proven or cardiac MRI-proven Re-AM.
• Comparison group: 372 patients with single acute myocarditis (S-AM).
• Primary outcome: composite of all-cause mortality, heart transplant, and major ventricular arrhythmias.

Main Results:

• Re-AM patients more frequently had a family history of cardiomyopathy and diffuse late gadolinium enhancement (LGE) on cardiac MRI.
• The extent of LGE increased between the first and second AM episodes in Re-AM patients.
• Re-AM patients faced a higher risk of the primary composite outcome and major ventricular arrhythmias compared to S-AM patients.

Conclusions:

• Recurrent acute myocarditis (Re-AM) represents a distinct clinical subgroup of AM.
• Re-AM is associated with a generally worse prognosis and a specific increased arrhythmic risk compared to S-AM.
• Family history of cardiomyopathy, autoimmune diseases, and ring-like LGE are independently associated with higher Re-AM risk.