Embedded Files
Polar H10 Fibrillation Search application uses the POLAR H10 heart rate monitor to detect suspicious episodes of Atrial Fibrillation (AFib). Atrial fibrillation is a heart condition that causes an irregular and often abnormally fast heart rate. This condition increases the risk of stroke, heart failure, and other heart-related complications. During AFib, the heart's upper chambers (the atria) beat chaotically and irregularly, out of sync with the lower chambers (the ventricles).
Symptoms of AFib can include a fast, pounding heartbeat, shortness of breath, light-headedness, and fatigue. Some people may not notice any symptoms at all.
The POLAR H10 bluetooth connection allows you to record in real time on your Android device, the electrocardiogram (ECG) as well as your heart rate.
Inter-patient ECG classification with convolutional neural network:
Inter-patient ECG classification with convolutional neural network:
The ECG signal is processed using a convolutional neural network to distinguish between normal beats and Atrial Fibrillation. The neural network makes it possible to detect the RR intervals (time interval between two beats) in the signal and it performs the morphological analysis of the ECG. The model has been trained on the CPSC2021 Challenge database and validated on 3 other Physionet databases: MITDB, LTAFDB and AFDB, with a f1score greater than 82% (see table below). This analysis allows to detect suspicious phases of Atrial Fibrillation. The detection is done in real time in the application as well as heart rate monitoring.
Permormance of Polar H10 Fibrillation Search on Physionet.org public databases
MITDB : MIT-BIH Arrhythmia Database
AFD : Atrial Fibrillation Database
LTAFDB : Long term Atrial Fibrillation Database
The user gives a time interval which defines the frequency of the ECG signal processing and POLAR H10 Fibrillation Search will give periodically voice indications on the presence of suspected Atrial Fibrillation as well as the average, maximum and instantaneous heart rate. It is possible to perform an analysis of the ECG signal from the beginning at any time. There is no time limit in using the application which can run for hours in the background allowing continuous monitoring of your heartbeats.
Post processing of records:
It is also possible to analyze ECG signals already stored on your device. These are saved in real time in the Documents folder of the Android device. Additional analysis of segment and intervals on the ECG using the Neurokit2 software has been integrated to the application. When launching the application for the first time, please indicate the ID of the Polar H10 device (written on the edge of the sensor) then restart the application.
Waves, intervals and segment analysis:
Additional analysis of segment and intervals on the ECG using the Neurokit2 software (Makowski, D., Pham, T., Lau, Z. J., Brammer, J. C., Lespinasse, F., Pham, H., Schölzel, C., & Chen, S. A. (2021). NeuroKit2: A Python toolbox for neurophysiological signal processing. Behavior Research Methods, 53(4), 1689-1696. https://doi.org/10.3758/s13428-020-01516-y) has been integrated to the application.
Interpretation of Waves/Segments/intervals:
Here are the main waves, segments and intervals typically observed in an ECG:
The QRS complex represents ventricular depolarization. The normal duration of the QRS complex is less than 0.12 seconds. This duration can, however, decrease during physical exercise. It will increase when the electrical impulse takes longer to pass through the ventricle. A widened QRS occurs in the case of bundle branch block (left or right), an anomaly linked to a delay in intraventricular conduction (hyperkalemia, side effects of certain medications) and during certain ventricular arrhythmias such as ventricular extrasystole or ventricular tachicardia.
The PR interval represents the time that it takes for the electrical impulse to travel through the atria to the ventricles. The normal PR interval is 0.12 to 0.22 seconds. When the conduction of the electrical impulse is reduced, usually due to slow conduction through the atrioventricular node, the length of the PR interval increases. When the PR duration exceeds 0.22s, a first degree AV block is present. The causes of first degree heart block can be an increased vagal tone, myocardial ischemia, degenerative fibrosis related to age, and some medications (beta-blockers, calcium channel blockers, digoxin, amiodarone). When the PR interval is shortened, it means there is and additional pathway other than the atrioventricular node. Pre-excitation syndromes like Wolff-Parkinson-White syndrome or Lown-Ganong-Levine syndrome should be suspected. The duration of the PR interval tends to decrease during exercise.
The P wave represents atrial depolarisation of right atrium and then left atrium in chronological order. The normal duration of the P wave is less than 0.12 seconds and its amplitude should be less than 0.25 mV. Peaked P waves (> 0.25 mV) occurs when the right atrial depolarisation last longer (right atrial enlargement). In that case the combination of the right and left waves results in a higher peak. When the left atrial depolarization last longer (left atrial enlargment), it results in a waveform larger than normal. The common abnormalities are called: P mitrale when we observe a large and bifid P wave due to left atrial enlargement often caused by mitral stenosis, P pulmonale in the case of high amplitude P wave due to right atrial enlargement usually caused by pulmonary hypertension, Inverted P wave when the electric impulse is generated outside of the sinoatrial node.
The duration of the P wave tends to increase during exercise.
The ST segment normally represents an electrically neutral area between ventricular depolarization (QRS complex) and repolarization (T wave) and should be flat on the ECG. The beginning of the ST segment is called the J point. Any displacement of the ST segment above or below baseline (the reference being the PR segment) is often measured at the J point. However it must be noted that during exercise, the J point is often depressed with an upsloping ST segment. For that reason it is recommended that during exercise, the measurement should be done at J-60 or J-80 points which are located respectively at 60ms and 80 ms (ST80) after the J point. A displacement (elevation or depression) is considered as normal between -0.1mV and +0.1mV. There are many causes for ST segment elevation including myocardial infarction, pericarditis, left ventricular hypertrophy and benign early repolarization. The causes for ST segment depression include myocardial ischemia, hypokalaemia and left ventricular hypertrophy.
The T wave is located after the QRS complex. It represents ventricular repolarisation. The T wave amplitude should not exceed 1mV and should be positive. T waves which are high and narrow are observed in hyperkalaemia. Inverted T waves (negative) occur for example in myocardial ischaemia and infarction, bundle branch block and ventricular hypertrophy but are normal in children and adolescents. The T wave amplitude may increase during exercise.
The QT interval represents the total duration of ventricular depolarization and ventricular repolarization. The normal duration of the QT interval should be less than 0.45 s. The QT interval shortens at faster heart rates and lengthens at slower heart rates. Common causes of a prolonged QT (>450ms) are hypokalaemia, hypomagnesaemia, hypocalcaemia, hypothermia, myocardial ischemia and some drugs (antiarrhythmic, antidepressants and antibiotics). The duration of the QT interval tends to decrease during exercise.
The R wave is located after the P wave and represents early ventricular depolarisation. R wave is the largest wave but its amplitude should be less than 2mV. High amplitude R wave may be due to ventricular hypertrophy.
The recordings are listed in chronological order. To start analyzing a recording, simply click on the corresponding date in the table. By clicking on a variable on the first line, we obtain a graph representing the history of the variable.
Warning: This application is for educational purposes only and does not replace a medical diagnosis. The Polar H10 belt is not a medical device and the predictions given by this application could be wrong. If you think you are experiencing heart rhythm disturbances, please consult your doctor.
INSTRUCTIONS
To connect to the Polar H10 it is necessary to wear the Polar belt. Press connection, the application will automatically detect your device. In case of connection difficulty, you can also indicate in the settings the number which is on the edge of your Polar H10, then exit and restart the application. If you still cannot connect please verify that your device is not already connected to another bluetooth device. Push the button connection to start recording on your device. The Polar H10 records an ECG file, and a file containing the heart rate. These files are saved in the Documents folder of your cell phone, in the POLARH10_ECG_androidstudio and POLARH10_HR_androidstudio subfolders.
In order to regularly have information on identified auricular fibrillation phases and heart rate, we enter the frequency of the periodic calculation in the parameters. All calculations are then carried out for the period given in the application settings, in order to have periodic and fast monitoring. After each cycle, those periodic data are merged in order to provide information on the number of fibrillation phases and the heart rate since the start of the recording. The number of fibrillation phases is then equal to the sum of fibrillation phases identified over each period. We can see the merged ECG signal by clicking on the left button and once the search is completed, press the button to the right to view the fibrillation phases. Each time you click on this button, the next fibrillation phases is displayed on the ECG.
The ECGLive button allows you to follow the ECG recording live over the last 60 seconds.
It is also possible to search for fibrillation phases from the start of the recording but this may take several minutes depending on the power of your device and the duration of the recording. Note that the results may be slightly different from those obtained with the periodic search, since in the latter case the search is carried out on segments of the ECG which are then merged and not on the entire signal. To search from start click on the left button then on the button to its right to view the fibrillation phases in the ECG.
Clicking on this button provides access to previously made recordings in a new page, and carry out a certain number of treatments.
Attention! Analysis of the ECG signal (search for peaks, intervals and segments) can be very long and depend on the power of your mobile phone and the duration of the recording.
Allows you to choose an ECG recording on your device and perform a new analysis for atrial fibrillation. An analysis of heart rate variability is also performed. Open the ECG file located in the POLARH10_ECG_androidstudio folder.
Allows you to locate the fibrillation phases identified on the recording that was imported.
Allows to view the ECG of the loaded recording.
Stops the current recording and starts a new recording.
Allows access to statistics on history of recordings.
Exports the results as a PDF file. Files are stored in the download directory. It is also possible to export the results as an EDF (European Data Format) file. The files are exported to the download directory.
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