Contents I. Introduction
Heart diseases are major causes of mortality in the developed countries. Their early diagnosis and treatment can effectively prevent the sudden death of patients. It is known that implantable cardiac devices such as pacemakers are widely used nowadays. A pacemaker is a medical device that uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart. However, one of the problems is the diagnosis of cardiac abnormalities via a pacemaker. This is because serious but infrequently occurring arrhythmias can be difficult to detect and analyze [1]. To solve it, various types of sensors, such as activity sensor, metabolic sensor and dual sensors, have been used to detect body activity, and measure some consequence of a physiological change during exercise or facing emotional changes (temperature and posture).
