Validation Study of WITHINGS BPM Core for the Detection of Atrial Fibrillation

BPM Core is a blood-pressure monitor with an build-in single-channel electrocardiogram similar to a lead I.

Primary objective:

The primary objective is to demonstrate that Withings BPM Core has acceptable sensitivity and specificity in the automatic identification of AF and SR in comparison with a gold-standard diagnosis from a 12-lead ECG by board certified cardiologists.

The algorithm classifies the device signals into four categories: normal sinus rhythm (RSN), AF, arrhythmia other than AF, or non-interpretable. The latter category includes signals of insufficient quality to be interpreted with confidence.

This classification will be compared to the diagnosis made by three independent, blinded cardiologists based on a 12-lead ECG. The final diagnosis retained will be decided by majority with adjudication by a consensus of 3 to 6 cardiologists. The sensitivity and specificity of the device will then be estimated.

Secondary objectives:

The first secondary objective is to assess the quality of tracings of the BPM Core armband thanks to a qualitative and quantitative comparison between BPM Core tracings and reference ECG ones, based on clinical evaluation criteria.

Firstly, three independent cardiologists who have not performed or read the reference ECG and do not know the patient's clinical files will make a diagnosis from the recordings from the BPM Core. There will be a majority vote to select the diagnosis. The cases where the three readers reached three different diagnosis will be reviewed by a panel of 3 to 6 board certified cardiologists who will decide by consensus. Sensitivity and specificity will be calculated relative to the reference ECG.

Secondly, quantitative analyses will be performed to assess the quality of ECG tracings provided by Withings BPM Core and its software, as follows:

• The visibility and polarity of the ECG waves (namely P-waves, QRS complexes and T-waves) will be determined by the cardiologists for each lead I signals recorded with Withings BPM Core and with the 12-channel ECG device. The assessment will be made on the 5th complete beat of the recording. For each of the waves (P, QRS and T), the agreement of visibility and the agreement of polarity (when both are visible) between the signals of Withings BPM Core and the reference ECG device will be computed.
• The duration of the main ECG intervals (namely QT interval, QRS width and PR interval) will be determined by the cardiologists for each lead I signal recorded by Withings BPM Core and the 12-channel ECG device. The measurement will be made with a caliper on the 5th complete beat of the recording. For each interval (QT, QRS, PR), the difference of length between the signals of Withings BPM Core and the reference ECG device will be computed.
• The heart rate will be first determined by the cardiologists for each lead I signal (recorded by Withings BPM Core and the 12-channel ECG device) which are diagnosed as NSR. The heart rate difference between the signals of Withings BPM Core and the reference ECG device will be computed. Second, the heart rate of the signals recorded with the BPM Core will be computed by the Withings software. The difference between the heart rate estimated by Withings software on Withings BPM Core signals and the heart rate determined by the cardiologists on the lead I signal from the ECG reference device will also be calculated.

The sponsor will make sure that the same cardiologist will not be asked to annotate both a Withings BPM Core signal and the corresponding lead I signal from the 12-channel ECG device. The sponsor will then centralize the annotations of Withings BPM Core tracings and of the ECG reference lead I signals and perform agreement calculations on synchronous pairs.

The second secondary objective is to verify the safety of use of the device by analyzing adverse effects.

The safety of use of the device will be assessed by the number of adverse effects.