A small percentage of cases of dermatomyositis are positive for anti-mitochondrial antibodies (AMA), a known marker for primary biliary cirrhosis. AMA-positive myositis is a rare disease that has been reported to be accompanied by myocarditis, resulting in low left ventricular function, supraventricular arrhythmias, and abnormalities of the conduction system. We present a case of AMA-positive myocarditis resulting in sinus arrest during general anesthesia. A 66-year-old female with AMA-positive myocarditis underwent artificial femoral head replacement for osteonecrosis of the femoral head under general anesthesia. During general anesthesia, a nine-second sinus arrest occurred without any inducement. The sinus arrest was thought to be influenced by not only over-suppression caused by severe supraventricular tachycardia derived from sick sinus syndrome but sympathetic depression caused by general anesthesia. Because of the potential for life-threatening cardiovascular events during anesthesia in patients with AMA-positive myositis, it was considered essential to provide adequate preoperative management and intraoperative monitoring during anesthesia for patients with this disease. Herein, we report our case with a literature review.