# Deep Learning-Based ECG Arrhythmia Classification: A Systematic Review
## 3 Results
### Performance Metrics  
To evaluate the classification performance of DL models, the commonly used performance metrics are overall accuracy (Acc), sensitivity (Sen), positive predictivity (Ppv), false positive rate (FPR), and \(F_{1}\) score. Sen and Ppv correspond to recall and precision rates, respectively. It can be seen that Acc (82.1%, 302), Sen (72%, 265), \(F_{1}\) score (59.8%, 220) are \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Paper**} & \multirow{2}{*}{**Paradigm**} & \multirow{2}{*}{\
\begin{tabular}{c} **Train/Validate** \\ **Data** \\ \end{tabular} } & \multirow{2}{*}{**Test Data**} & \multirow{2}{*}{**Algorithm**} & \multirow{2}{*}{**Class**} & \multirow{2}{*}{
\begin{tabular}{c} **Cross-** \\ **Validation** \\ \end{tabular} } & \multicolumn{4}{c}{**Performance**} & \\ \cline{5-10}  & & & & & & & & **Acc** & \(F_{1}\) & **Sen** & **Ppv** & **Spe** \\ \hline
[82] & Intra- & MITDB & MITDB & DenseNet- & 4: N, S, V, F & 10-fold & 99.44 & 95.89 & 95.69 & 96.11 & 99.32 \\  & Inter- & MITDB & D1S1 & MITDB & D2S2 & EliSTM & 92.37 & 63.49 & 68.29 & 60.35 & 94.51 \\ \hline
[83] & Intra- & MITDB & MITDB & MITDB & D1 & CNN & 5: N, S, V, F, Q & 10-fold & 99.48 & / & 96.97 & 98.83 & 99.87 \\  & Inter- & MITDB & D1 & MITDB & D2S2 & CNN & 5: N, S, V, F, Q & 88.34 & / & 90.90 & 48.25 & 88.51 \\ \hline
[84] & Intra- & Fantasia+ & Fantasia+ & & & & / & 99.85 & 99.52 & 99.85 & / & 99.84 \\  & Inter- & INCART & INCART & & & & & & & & \\  & & Fantasia+ & Fantasia + & & CNN-LSTM & 2: N, CAD & & & & & \\  & Inter- & INCART (by & INCART (by & & & & & & \\  & Subjects) & Subjects) & & & & & & & & \\ \hline
[85] & Intra- & MITDB & MITDB & MITDB & D2S & O-WCNN & 4: N, S, V, F & 10-fold & 99.58 & 99.28 & 99.2 & / & 99.15 \\  & Inter- & MITDB & D1 & MITDB & D2S & & & & 99.43 & 92.05 & 91.06 & 93.50 & 99.69 \\ \hline
[81] & Intra- & AFDB & AFDB & AFDB & & & 5-fold & 97.80 & / & 98.98 & 95.76 & 96.95 \\  & Inter- & AFDB & MITDB & & & & & 89.30 & / & 99.82 & 51.71 & 87.94 \\  & Inter- & AFDB & NSRD & & & & / & / & / & / & 95.01 \\ \hline
[86] & Intra- & MITDB & MITDB & MITDB & & & & 10-fold & 99.56 & 96.40 & 95.90 & 97.14 & 99.47 \\  & Inter- & MITDB & D1S1 & MITDB & D2S & CNN+BLSTM & 9: N, S, V, F, Q & 96.77 & 77.84 & 74.89 & 81.24 & 95.16 \\ \hline
[28] & Intra- & PTB-XL & PTB-XL & & & & / & 89.92 & 90.70 & 91.40 & 90.01 & / \\  & Inter- & VIP-XL (by & PPS-XL (by & CNN-FWS & & abnormal & & 90.05 & 90.20 & 88.90 & 91.50 & / \\  & subject) & subject) & & & & & & & & \\ \hline
[87] & Intra- & PTB & PTB & MLA-CNN- & 6 & & 5-fold & 99.11 & / & 99.02 & 99.10 & / \\  & Inter- & PITB & PTB & BiGRU & & & 62.94 & / & 63.97 & 63.00 & / \\ \hline
[88] & Intra- & MITDB & MITDB & MITDB & CNN & & & & & \\  & Inter- & MITDB & D5S1 & MITDB & D5S2 & & & & 96.36 & / & 70.6 & 48.10 & 96.16 \\ \hline
[89] & Intra- &
\begin{tabular}{c} Tongi \\ Hospital, \\ Database \\ \end{tabular} & DCNN & 26 & / & / & 91.3 & 89.1 & / & 99.7 \\  & China & China & & & & & & \\  & & Tongi & & & & & & & \\  & Hospital, \\  & China & & & & & & & & & \\ \hline
[90] & Intra- & MITDB & MITDB & CNN & 5: N, S, V, F, Q & / & 99.31 & / & 73.66 & 69.6 & 98.83 \\  & Inter- & MITDB DS1 & MITDB DS2 & & & & 90.22 & / & 35.64 & 27.71 & 87.87 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparative summary table of inter/intra-patient paradigms studies. the three most used performance metrics to evaluate the classification performance of the DL models for arrhythmia classification. Regardless of the evaluation paradigm and other conditions, such as task and number categories to be classified, we simply calculate the average of those metrics and find that the classification accuracy of the DL models in the selected studies is already above 95%, while other metrics such as \(F_{1}\) score, sensitivity, positive predictivity, and specificity are relatively lower, within the range of 80-95%. Furthermore, interesting comparisons between the DL models and professional cardiologists are performed in [110,111].