Table 4 Pseudo code of the proposed methodology to find CV of ECG localized features.
From: Phase Space Reconstruction Based CVD Classifier Using Localized Features
1. Requirement: Find the CV distribution of all the localized features |
2. E(t) = Healthy + Unhealthy ECG signal |
3. Ef(t) = filtering(E(t)) |
4. Normalization: En(t) = (Ef(t) − Efmin(t))/(Efmax(t) − Efmin(t)) |
5. Extraction of boundaries: for i = 1 to length (En(t)) {E(1), E(2), E(3), —E(n),} = BD[En(t)] endfor where E(n) is the nth ECG beat. |
6. Extracting ECG Features: for i = 1 to n {PR[i], QRS[i], QT[i]} = FE[E(i)] endfor |
7. Taking QT interval array for PSR analysis: QT(i), i ∈ {1, 2, 3, ....n} |
8. Applying Sliding window on QT interval array: for z = 1 to n − 19 SW(t) = {QT(z + 1), QT(z + 2), QT(z + 3)....QT(z + 19)} PSR_Image(k) = plot(SW(t), SW(t − 20)) endfor SW = Sliding Window. |
9. Box-count array: for x = 1 to k Box_count_array(x) = No. ofBlackBoxes(PSR_image(x)) endfor |
10. Sliding window on Box-count distribution: for m = 1 to x − 19 CV(m) = CV(Box_count_array(m), Box_count_array(2), Box_count_array(3))...Box_count_array(m + 19) endfor |
11. for i = 1 to m Thmax(i) = max[CV(i){1:a}] Thmin1(i) = min[CV(i){b:end}] endfor Note: point ‘a’ and ‘b’ in CV plot are corresponding to ‘Unhealhty QT start’ and ‘Healthy QT end’ windows of Fig. 14 |
12. Thfinal_max_QT = max(Thmax(1), Thmax(2), Thmax(3)..Thmax(m)) Thfinal_min_QT = min(Thmin(1), Thmin(2), Thmin(3)..Thmin(m)) |
13. Thfinal_min_QT and Thfinal_max_QT are the two thresholds of CV corresponing to QT interval, the similar procedure is followed for PR interval and QRS complex to find thresholds. |