C66 LONG TERM FOLLOW–UP OF PATIENTS WITH BIOPSY– PROVEN DIAGNOSIS OF MYOCARDITIS AND VENTRICULAR ARRHYTHMIAS

Abstract

Abstract Background The diagnosis and management of patients with myocarditis with ventricular arrhythmic (VA) onset is one of the major challenging issues faced by physicians. Objective We aimed at evaluating the natural history of patients with an endomyocardial biopsy–proven diagnosis of myocarditis with a VA manifestation at the time of diagnosis. Methods From January 2013 to October 2021, 243 consecutive patients with unexplained VAs underwent a complete diagnostic work–out, including endomyocardial biopsy. All patients with a biopsy–proven diagnosis of myocarditis were included in the study. Results 104 patients were enrolled (mean age: 54 ± 16 years; 75% male). The presenting arrhythmic manifestation was syncope/aborted sudden death in 21 (20.2%) patients, sustained ventricular tachycardia (VT) in 16 (15.4%), nonsustained VT in 29 (27.9%) and frequent premature ventricular complexes in 38 (36.5%). Patients with severe systolic dysfunction (Ejection Fraction<35%) were 63.5%. Late gadolinium enhancement (LGE) and myocardial oedema were detected at cardiac magnetic resonance (CMR) in 91.8% and 30% patients, respectively. Thirty–eight (36.5%) patients received an implantable cardioverter defibrillator (ICD) for primary (n = 14; 36.8%) or secondary (n = 24; 63.2%) prevention of sudden cardiac death (SCD). The mean follow–up was 69 ± 32 months: cardiovascular (CV) death was 15.4% while the recurrence of sustained Vas was 27.9%. Among ICD patients, 13 (34.2%) had an appropriated therapy of the device and arrhythmic storm occurred in 3 (23.1%) of them. The combined endpoint of sustained VA/ICD therapy/CV death occurred in 35.6%. The most important independent predictor of VAs was the presence of LGE [Odds Ratio: 9.100; Confidence of Interval: 1.125 – 73.609; p–value: 0.04]. Conclusion Among patients with a diagnosis of myocarditis and VAs, 35.6% had recurrences of VA/ICD therapy/CV death during follow–up. The presence of LGE at CMR stratifies the risk of VA recurrence.