Table 2.
Conventional Morphological Features of Heartbeats.
| Features | Description | Reference |
|---|---|---|
| QRS complex duration | The time interval between the onsite of the Q wave and offsite of the S wave |
[30,31,38] [73,74,75] |
| QRS velociy left | The QRS slope velocity calculated for the time-interval between the QRS complex onset and the first peak |
[30,73] |
| QRS velociy right | The QRS slope velocity calculated for the time-interval between the first peak and the second peaks |
[30,73] |
| QRS complex area | The sum of the positive area and absolute negative area in the QRS complex | [30,73] |
| QRS complex morphology | Sample points from the QRS onsite to the QRS offsite | [31] |
| QRS complex AC power | The total power content of the QRS complex signal | [32] |
| QRS complex Kurtosis | The kurtosis indicates the peakedness of the QRS complex | [32] |
| QRS complex Skewness | The skewness measures the symmetry of the distribution of the QRS complex | [32] |
| Q wave valley | The valley value of Q wave | [75] |
| S wave valley | The valley value of S wave | [75] |
| T wave peak | The peak value of T wave | [75] |
| T wave duration | The duration from the QRS offsite to the T wave offsite | [31] |
| T wave morphology | Sample points from the QRS offsite to the T wave offsite | [31] |
| P wave flag | A Boolean value indicates the presence or absence of the P wave | [31] |
| P wave duration | The duration from the P wave onsite to the P wave offsite | [74] |
| P wave morphology | Sample points from the P wave onsite to the P wave offsite | [34,74] |
| PR interval duration | The duration from the P wave onsite to the QRS complex onsite | [74] |
| PR interval morphology | Sample points from the P wave onsite to the QRS complex onsite | [34] |
| QT interval duration | The duration from the QRS complex onsite to the T wave offsite | [74] |
| QT interval morphology | Sample points from the QRS complex onsite to the T wave offsite | [34,75] |
| ST interval morphology | Sample points from the S wave valley to the T wave offsite | [75] |
| Max peak(R peak) value | The maximum amplitude of the heartbeat | [30,73,75] |
| Min peak value | The minimum amplitude of the heartbeat | [30,73] |
| Positive QRS complex area | The area of the positive sample points in the QRS complex | [30,73,74] |
| Negative QRS complex area | The area of the negative sample points in the QRS complex | [30,73,74] |
| Positive P wave area | The area of the positive sample points in the P wave | [74] |
| Negative P wave area | The area of the negative sample points in the P wave | [74] |
| Positive T wave area | The area of the positive sample points in the T wave | [74] |
| Negative T wave area | The area of the negative sample points in the T wave | [74] |
| Absolute velocity sum | Sum of the absolute velocities in the pattern interval | [30,73] |
| Ima | Time-interval from the QRS complex onset to the maximal peak | [30,73] |
| Imi | Time-interval from the QRS complex onset to the minimal peak | [30,73] |
| Pre-RR interval | The RR interval between the heartbeat and its previous heartbeat | [31,71,74] |
| Post-RR interval | The RR interval between the heartbeat and its following heartbeat | [31,71,74] |
| Post-PP interval | The PP interval between the heartbeat and its following heartbeat | [74] |
| Average-RR interval | The average value of all valid RR intervals in the ECG record | [31,71,74] [32,75] |
| Local Average-RR interval | The average value of ten valid RR intervals surrounding the heartbeat | [31,71,74] |
| Normalized signal | The heartbeat sample points are normalized and down-sampled to have a mean of zero and standard deviation of one |
[76,77,78] |
| Raw/downsampled ECG signal | The unprocessed ECG signal or the only processing on the signal is downsampled | [36,79] |