Fig. 4: ECG measurement by flexible devices.

a Balloon catheter for the cardiac electrophysiological mapping and ablation therapy. b The image of the high-density electrodes on a porcine heart for the recording of the spatial-temporal cardiac electrical rhythms in real time, the inset shows the circuit unit and the enlarged view of the electrode array; and c the recorded wave of cardiac activation propagating of the entire 288-electrodes. d The image of the epidermal electronic system on the human skin for the ECG measurement, the inset show the enlarged view of the mesh design; e equivalent circuit model of the epidermal electronic system; and f comparisons of the ECG recordings with traditional flat electrode. a Reproduced with permission¹¹⁷ (Copyright 2011, Nature Publish Group). b, c Reproduced with permission¹¹⁸ (Copyright 2010, the American Association for the Advancement of Science). d–f Reproduced with permission⁸⁵ (Copyright 2014, Wiley-VCH).