Patients affected usually present with high levels of cardiac biomarkers (Troponin I or T, brain natriuretic peptide [BNP] or N-terminal pro B-type natriuretic peptide [NT-proBNP]), electrocardiographic (EKG) changes consistent with myocarditis (abnormal ST segments or low voltage QRS in the presence of edema), ischemia (abnormal ST segments, T wave inversion) or ventricular tachyarrhythmia (e.g. ventricular tachycardia [VT] or ventricular fibrillation [VF]). This evidence concerns the gene NPPB and ventricular fibrillation.