Table 3.

Diagnostic criteria for clinically suspected myocarditis.

Clinical presentations A acute chest pain, pericarditic, or pseudo-ischaemic New-onset (days up to 3 months) or worsening of: dyspnoea at rest or exercise, and/or fatigue, with or without left and/or right heart failure signs Subacute/chronic (3 months) or worsening of: dyspnoea at rest or exercise, and/or fatigue, with or without left and/or right heart failure signs Palpitation, and/or unexplained arrhythmia symptoms and/or syncope, and/or aborted sudden cardiac death Unexplained cardiogenic shock

Diagnostic criteria I.ECG/Holter/stress test features Newly abnormal 12 lead ECG and/or Holter and/or stress testing,any of the following:Ito III degree atrioventricular block,or bundle branch block,ST/T wave change (ST elevation or non ST elevation, T wave inversion), sinus arrest, ventricular tachycardia or fibrillation and asystole, atrial fibrillation, reduced R wave height, intraventricular conduction delay (widened QRS complex), abnormal Q waves, low voltage, frequent premature beats, supraventricular tachycardia II.Myocardiocytolysis markers Elevated TnT/TnI III.Functional and structural abnormalities on cardiac imaging (echo/angio/CMR) New,otherwise unexplained LV and/or RV structure and function abnormality(including incidental finding in apparently asymptomatic subjects):regional Wall motion or global systolicordiastolic function abnormality, with or without ventricular dilatation, with or without increased wall thickness, with or without pericardial effusion, with or without endocavitary thrombi IV.Tissue characterization by CMR Edema and/or LGE of classical myocarditic pattern (see text)

Clinically suspected myocarditis if ≥ 1 clinical presentation and ≥1 diagnostic criteria from different categories, in the absence of: (1) angiographically detectable coronary artery disease (coronary stenosis ≥50%); (2) known pre-existing cardiovascular disease or extra-cardiac causes that could explain the syndrome (e.g., valve disease, congenital heart disease, hyperthyroidism, etc.) (see text). Suspicion is higher with higher number of fulfilled criteria. a If the patient is asymptomatic ≥2 diagnostic criteria should be met.