Myocarditis is an inflammatory disease of the heart muscle which is mostly caused by viruses, bacteria, parasites, toxic substances/drugs or by primary autoimmune mechanisms. Signs of heart failure (dyspnea, reduced resilience, tendency to edema), thoracic pain, palpitations / arrhythmias / syncope, as well as (potentially) lethal clinical conditions in the sense of a cardiogenic shock or sudden cardiac death can be found.

In 2015, the European Society of Cardiology (ESC) gave a IIa recommendation for the indication of an ICD vest restoration as "bridging" until the acute phase subsides (possibly normalisation of the left ventricular pump function with reduced probability of malignant cardiac arrhythmia) or until ICD implantation in cases of severe LV dysfunction and/or ventricular electrical instability. The Monitoring and analysis of malignant cardiac arrhythmias are therefore crucial in the treatment of acute myocarditis.

The aim of this study is to observe the long-term incidence of ventricular arrhythmias in patients diagnosed with myocarditis and to analyze the MRI and echocardiographic data obtained as potential predictive factors for the occurrence of ventricular arrhythmias.

Myocarditis is an inflammatory disease of the heart muscle, which is mostly caused by viruses, bacteria, parasites, toxic substances/drugs or by primary autoimmune mechanisms. In the first phase of acute myocarditis direct cell damage, in a second phase myocardial inflammation with additional myocardial damage can be observed. Symptoms vary widely and may include signs of heart failure (dyspnoea, reduced exercise capacity, edema tendency), chest pain, palpitations / arrhythmias / syncope, and (potentially) lethal clinical conditions such as cardiogenic shock or sudden cardiac death. Predictors of increased mortality are syncopes, malignant arrhythmias EF≤35% or heart failure NYHA III-IV. ICD implantation is recommended <3 months after manifestation only in exceptional situations (e.g. following resuscitation). The European Society of Cardiology (ESC) issued a IIa recommendation in 2015 for the indication of ICD vest fitting as "bridging" until the acute phase subsides (possible normalization of left ventricular pumping function with reduced probability of malignant cardiac arrhythmias) or until ICD implantation in cases of severe LV dysfunction and/or ventricular electrical instability is necessary. The observation, monitoring and analysis of malignant cardiac arrhythmias are therefore crucial in the treatment of acute myocarditis.

The aim of this study is to observe the long-term incidence of ventricular arrhythmias in patients with diagnosed myocarditis and to analyze the MRI and echocardiographic data obtained as potential predictive factors for the occurrence of ventricular arrhythmias.

The study is a prospective multicenter registry study. All potentially stressful measures and examinations such as blood sampling and echocardiography - except for follow-up MRI examinations - are carried out at our centre as standard clinical progress assessment, even independently of participation in the registry. The indication for biomonitor implantation is given after initial screening by means of a 24h-LZ-ECG with positive results (detection of ventricular arrhythmias). The registry study is performed with approved IECDs (Implantable electronic cardiovascular devices: Biomonitor (BioMonitor 2-AF, BioMonitor 3-AF (after release)), Biotronik® ICD) as well as WCD (Wearable Cardioverter Defibrillator, Zoll® LifeVest) and Biotronik® Cardio Messenger. The implantation is carried out exclusively according to the indication/testing guidelines. Thus, there are no risks or disadvantages for the participating patient.

The primary aim of the study is to monitor the long-term incidence of ventricular arrhythmias in patients with diagnosed myocarditis and to identify potential predictive factors for their occurrence.

Secondary goal is to analyze the long-term survival and need for heart transplantation and to identify MRI/echocardiographic parameters as determinants of arrhythmias.

Inclusion Criteria:

• secured myocarditis via MRT / endomyocardial biopsy
• ventricular arrhythmias (≥ 5 beats) in the ECG / LZ ECG with clinical indication for a WCD system/ biomonitor/ or the indication for primary/secondary prophylactic ICD implantation
• presence of informed consent
• age >18 and <85 years

Exclusion Criteria:

• Participation in another study with an active treatment group
• Pregnant or breastfeeding women

The groups will be selected from all patients attending the participating hospitals.