Wireless, minimized, stretchable, and breathable electrocardiogram sensor system

Home-use, wearable healthcare devices may enable patients to collect various types of medical data during daily activities. Electrocardiographic data are vitally important. To be practical, monitoring devices must be wearable, comfortable, and stable, even during exercise. This study develops a breathable, stretchable sensor sheet by employing a kirigami structure, and we examine the size dependence of electrocardiographic sensors. Because the kirigami film has many holes, sweat readily passes through the sensor from the skin to the environment. For comfort, in addition to breathability, electrocardiographic sensor size is minimized. The limitation of the size is studied in relation to the signal-to-noise ratio of electrocardiographic signals, even under exercise. We found that the optimal size of the sensor is ∼200 mm² and the distance between electrodes is 1.5 cm. Finally, long-term wireless electrocardiographic monitoring is demonstrated using data transmission to a smart phone app during different activities.