. 2021 Oct 2;9(10):1318. doi: 10.3390/healthcare9101318
© 2021 by the authors.
Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Figure 2.
Heartbeat cycle waveform and R–R interval.