https://www.selleckchem.com/pr....oducts/-r-s--3-5-dhp
RESULTS High similarity with P value varying between .97 and 1.0 in both positions was found. The correlation coefficient of the heart-rate-variability indexes was perfect (r = 1.0; P = .0 for all variables. The constant error, standard error of estimation, and limits of agreement between ECG and the smartphone app were considered small. CONCLUSION The smartphone app and chest strap provide excellent ECG compliance for all variables in the time domain, frequency domain, and nonlinear indexes, regardless of the assessed position