  Objectives: With the technological advancements in the field of tele-health
monitoring, it is now possible to gather huge amounts of electro-physiological
signals such as electrocardiogram (ECG). It is therefore necessary to develop
models/algorithms that are capable of analysing these massive amounts of data
in real-time. This paper proposes a deep learning model for real-time
segmentation of heartbeats. Methods: The proposed algorithm, named as the
DENS-ECG algorithm, combines convolutional neural network (CNN) and long
short-term memory (LSTM) model to detect onset, peak, and offset of different
heartbeat waveforms such as the P-wave, QRS complex, T-wave, and No wave (NW).
Using ECG as the inputs, the model learns to extract high level features
through the training process, which, unlike other classical machine learning
based methods, eliminates the feature engineering step. Results: The proposed
DENS-ECG model was trained and validated on a dataset with 105 ECGs of length
15 minutes each and achieved an average sensitivity and precision of 97.95% and
95.68%, respectively, using a 5-fold cross validation. Additionally, the model
was evaluated on an unseen dataset to examine its robustness in QRS detection,
which resulted in a sensitivity of 99.61% and precision of 99.52%. Conclusion:
The empirical results show the flexibility and accuracy of the combined
CNN-LSTM model for ECG signal delineation. Significance: This paper proposes an
efficient and easy to use approach using deep learning for heartbeat
segmentation, which could potentially be used in real-time tele-health
monitoring systems.
