## 3 Results
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Ref**} & \multirow{2}{*}{**Pop. Size**} & \multirow{2}{*}{**Age**} & \multirow{2}{*}{**Sex**} & \multicolumn{2}{c}{**Clinical Information**} \\ \cline{5-6}  & & & & **Health Status** & **Details** \\ \hline
[19] & 21 & Adult & 17 M; 4 F & D & Cardiomyopathy \\
[20] & 43 & Adult & 27 M; 16 F & 23 D; 20 H & Ulcerative colitis; NA \\
[21] & 60 & Young adult & 60 M; 0 F & H & NA \\
[22] & 180 & Adult & 67 M; 113 F & D & Chronic insomnia \\
[23] & 41 & Adult & 41 M; 0 F & H & NA \\
[24] & 39 & Adult & 19 M; 20 F & D & Diabetes \\
[25] & 62 & Adult & 24 M; 38 F & D & Dialysis \\
[26] & 71 & Adult & 48 M; 23 F & D & Dialysis \\
[27] & 30 & Adult & 21 M; 9 F & H & NA \\
[28] & 28 & Adult & 10 M; 18 F & 14 D; 14 H & Sleepwalking; NA \\
[29] & 114 & Adult & 31 M; 83 F & D & Psychiatric disorder \\
[30] & 114 & Adult & 90 M; 24 F & D & Cardiomyopathy \\
[31] & 56 & Adult & UA & 36 D; 20 H & Myocardial infarction; NA \\
[32] & 504 & Adult & 375 M; 129 F & D & Coronary artery disease \\
[33] & 155 & Adult & 125 M; 30 F & 108 D; 47 H & Myocardial infarction \\
[34] & 170 & Adult & 146 M; 24 F & D & Heart failure \\
[35] & 31 & Young adult & UA & H & NA \\
[36] & 52 & Adult & 22 M; 30 F & D & Cardiomyopathy \\
[37] & 87 & Infant & 51 M; 36 F & 58 D; 29 H & Congenital heart disease; NA \\
[38] & 22 & Fetal & UA & D & Preterm delivery \\
[39] & 51 & Adult & 51 M; 0 F & D & Coronary artery disease \\
[40] & 12 & Fetal & UA & D & Preterm delivery \\
[41] & 73 & Adult & 42 M; 31 F & 47 D; 26 H & Sleep disorder; NA \\
[42] & 96 & Adult & 23 M; 73 F & D & COVID-19 \\
[43] & 817 & Adult & 670 M; 147 F & D & Myocardial infarction \\
[44] & 17 & Young adult & 7 M; 10 F & 6 D; 11 H & Panic disorder; NA \\
[45] & 680 & Infant to young adult & 382 M; 298 F & H & NA \\
[46] & 14 & Newborn & UA & D & Preterm delivery \\
[47] & 41 & Adult & 15 M; 26 F & D & Cardiomyopathy \\
[48] & 47 & Adult & 25 M; 22 F & D & Heart rhythm disorder \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the populations studied in the included documents. Figure 2: Distribution of document publication years. Figure 3 further explores the health status of the studied populations. Specifically, panel A shows a pie chart representing whether the population was healthy or diseased, while panel B shows a pie chart representing the different pathologies affecting the diseased populations. Of the included documents, 7 studies enrolled healthy populations, while 15 studies considered patients with cardiac pathologies. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Ref**} & \multirow{2}{*}{**Pop. Size**} & \multirow{2}{*}{**Age**} & \multirow{2}{*}{**Sex**} & \multicolumn{3}{c}{**Clinical Information**} \\ \cline{5-6}  & & & & **Health Status** & **Details** \\ \hline
[49] & 44 & Adult & 44 M; 0 F & H & NA \\
[50] & 396 & Adult & 283 M; 113 F & D & Ventricular systolic disfunction \\
[51] & 523 & Adult & 264 M; 259 F & H & NA \\
[52] & 47 & Adult & 25 M; 22 F & D & Heart rhythm disorder \\
[53] & 53 & Adult & 31 M; 22 F & D & Chronic stroke \\
[54] & 134 & Adult & 49 M; 85 F & D & Heart rhythm disorder \\
[55] & 50 & Adult & 20 M; 30 F & D & Temporal lobe epilepsy \\
[56] & 123 & Adult & 123 M; 0 F & 90 D; 33 H & Cardiomyopathy; NA \\
[57] & 5 & Adult & 2 M; 3 F & D & Focal epilepsy \\ \hline \hline \end{tabular} Ref: reference; Pop. Size: population size; M: male; F: female; D: diseased; H: healthy; UA: unavailable; NA: not applicable.  
\end{table} 
Table 1: _Cont._  
Figure 3: Pie chart describing the health status of the populations studied in the included documents: (**A**) reports the percentage of studies involving healthy and diseased populations; (**B**) reports the percentage of studies involving diseased populations affected by various pathologies.