Objective The Objective of the study is to compare the ECG recordings using a novel mobile ECG recorder (EPI Mini) with a clinically validated mobile phone with ECG recording function (EPI Life).
Methods The EPI Mini and EPI Life are ECG recorders that use the same type of ECG chip modules, same surface electrodes and are able to record ECG following direct contact of the inbuilt contact electrodes with skin surfaces. The ECG recordings from EPI Life have been clinically validated with standard 12 lead ECG recordings. While the EPI Life is a mobile phone which allows the recording of ECGs and its transmission to a 24 hour centre, the EPI Mini is a mobile device that is a scaled down version of the EPI Life which records the ECG and transmits it wirelessly through smartphones. 30 consecutive healthy individuals aged 18 to 48 years consented to this prospective study. ECG recording using the EPI Mini device was performed, followed immediately by the recording of ECG using the EPI Life device in 3 different lead positions. ECG recordings were performed using modified limb leads I and II (mL I and mL II) and modified V5 precordial lead (mV5), and the optimal ECG recordings were compared. ECG parameters that were compared include ECG morphology (pattern and orientation of p wave, QRS complex, ST segment and T wave), QRS amplitude (R wave, S wave and R + S waves) and ECG parameters (PR interval and QT interval). The data were statistically assessed using linear regression analysis, as the Objective was to assess the correlation between the two modalities of ECG recording. Analysis was made between two variables, with X representing data from EPI Life ECG recordings and Y representing data from EPI Mini ECG recordings. From the data, the best fit value for the slope and P values were calculated.
Results A total of 180 ECG recordings were obtained for comparison; 90 ECG recordings using EPI Life and 90 recordings using EPI Mini. The linear regression graphs show that there was good correlation, as demonstrated by the linearity of the units, X and Y plotted on the graph for QRS amplitude (R wave, S wave and R + S waves) and ECG parameters (PR interval and QT interval) for all 3 leads. The R wave, S wave, R + S waves, PR interval and QT interval had best fit value for the slope of 1.0623, 1.392, 1.120, 0.855 and 1.141 respectively for mL I. The R wave, S wave, R + S waves, PR interval and QT interval had best fit value for the slope of 1.021, 1.031, 1.025, 0.991 and 1.011 respectively for mL II. The R wave, S wave, R + S waves, PR interval and QT interval had best fit value for the slope of 0.951, 1.148, 1.034, 0.856 and 1.073 respectively for mV5. The P values were found to be less than 0.0001 for all the quantitative parameters that were analysed. There was 100% correlation of the ECG morphology for ECG recordings from both devices for all the subjects when comparing the mL I, mL II and mV5 leads.
Conclusions There was statistically significant correlation between the quantitative ECG parameters recorded using the novel EPI Mini and the clinically validated EPI Life. In addition, the data showed that there was good qualitative correlation when comparing between the morphology of the ECGs recorded using both devices.