Myocarditis has a wide range of symptoms, ranging from mild chest pain and dyspnea to cardiogenic shock and death. We encountered a case of fatal myocarditis with various arrhythmia, including uncontrolled ventricular tachycardia (VT), a high degree atrioventricular block with a long pause, and a complete atrioventricular block. The patient had deteriorated even though conservative heart failure therapy, antiarrhythmic drugs, and pacing therapy were given. Long-lasting and various types of VT in patients with myocarditis might reveal an electrically unstable status of the myocardium due to extensive invasion of myocarditis. In the case of fatal myocarditis, an aggressive medical approach that includes immune therapy sometimes seems needed.