## 6 Beat Variations for MIT-BIH Dataset  
Another discrepancy found while reviewing the existing literature using the MIT-BIH arrhythmia database is that not all studies considered the same number of beats, which impacts the R-peak validation results and fair methodological comparison. The total number of actual beats is 109,494 for all 48 records as available in the PhysioNet database. This number, 109,494, serves as the standard from which we can deduce the following [94]:  
* If the literature shows a higher number, it means non-beats have been included in the results. * If the numbers are lower than 109,494, it indicates that beats have been removed, which should be thoroughly discussed in the manuscript. In the literature, [PERSON] et al. reported the total number of beats as 109,401, 93 fewer than the standard 109,494, indicating they missed valid beats in their final statistical results [31]. Additionally, they claimed that the total beats in the MIT-BIH dataset are 116,137 but did not provide a rationale for this figure. Even after reviewing the PhysioNet database and archives, the total number of actual beats (109,494) and non-beats (3153) amounts to 112,647, not 116,137. [PERSON] et al. reported the total number of beats as 109,474 [39]. They used fewer beats for records 100, 106, 107, 108, 116, 118, 119, 201, 205, 207, 208, 209, 210, 213, 215, 222, and 233, indicating that they missed many actual beats. They also used more beats in records 101, 105, 115, 121, 123, 124, 200, 203, and 214, showing that they have added some non-beats to the results of these records. [PERSON] et al. reported the total number of beats as 109,497 [66]. Upon reviewing the number of beats for each record in their manuscript, we found that the reported beats for record 109 are 3 more than the original 2532 beats, which is only possible if all 3 non-beats are added to the final count. [PERSON] et al. reported a total number of beats of 109,267, fewer than 109,494 [67]. They also skipped beats from every record of the MIT-BIH dataset but did not mention the timestamps to show which  
Figure 8: WFDB comparator bxb excluding a non-beat. samples were skipped in their manuscript. [PERSON] et al. reported the total number of beats as 109,510 [68]. They used more beats in records 103, 108, 207, 214, and 217, indicating that they have added non-beats into the final count without specifying. [PERSON] et al. reported 91,314 beats using fewer samples from each record [40]. They skipped the first 5 min of each record to comply with the WFDB validation tool mxm settings. The rationale is to allow the signal to stabilize and reduce the impact of any initial artifacts and noise that may be present. [PERSON] et al. claimed to use a total of 116,137 beats [43]. However, contrary to their claim, the actual number of beats used per record in their manuscript yields a total of not more than 109,809, which is still higher than the actual beat count of 109,494. Similarly, [PERSON] et al. [41] also reported the total number of beats as 116,137, but recalculation shows the total number to be 109,809 beats used in their manuscript. [PERSON] et al. [69] also claimed to use the complete number of beats of the MIT-BIH arrhythmia dataset but reported 108,494, 1000 fewer than the actual count of 109,494. These discrepancies emphasize the necessity of uniformity and transparency in reporting the total beats used and timestamps for the skipped segments while validating the R-peak detector. Table 1 also provides a comprehensive overview of the information about beats skipped, where NG indicates unavailable information from referenced papers. This overall discussion leads to three conclusions:  
1. Inconsistency in reporting no. of beats makes it difficult to compare results directly since performance metrics (accuracy, precision, recall, etc.) vary depending on the size and composition of the dataset. 2.