# Characterization of Cardiac Fat in Atrial Fibrillation Patients Prior to Ablation Treatment
## 3 Results
### Factors Influencing Different Cardiac Fat Parameters
However, a larger total cardiac fat area was observed in males than females only across overweight and obese patients but not in normal-weight patients (see green bracket in Figure 1f,g). In normal-weight patients (yellow box plot in Figure 2), the area of EAT, PAT, and total cardiac fat in end-systolic phase is significantly higher in >60 years age group than 40 to 50 years age group (see green brackets in Figure 2a,c,f, \(p\) \(<\) 0.05). Similar results were obtained with the areas of EAT and PAT in end-diastolic phase (top upper green bracket in Figure 2b,d) but not with total cardiac fat (Figure 2g). This may suggest that cardiac fat parameters increase with age in normal weighted patients with paroxysmal AF. In overweight patients, there were larger EAT areas in end-diastolic phase in the age group 50 to 60 years compared with age group 40 to 50 years (see lower green bracket Figure 2b, \(p\) \(<\) 0.05). In obese patients, we observed an apparent trend of the EAT areas in the end-systolic and end-diastolic phases increasing with age until 60 years, at which point there showed a slight drop, although not statistically significant (Figure 2a,b). Notably, EAT and PAT were not associated with CHA2 DS2-VASc stroke-risk score, suggesting that cardiac fat may be an independent marker of AF. \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & **Normal (n = 45)** & **Overweight (n = 79)** & **Obese (n = 74)** & _p-Value_ \\ \hline Epicardial Adipose Tissue (EAT) & & & & \\ \hline EAT End-systolic area (cm\({}^{2}\)) & 10.8 (\(\pm\)4.5) + & 14.7 (\(\pm\)5.7) \(\ddagger\) & 17.6 (\(\pm\)5.1) \# & \textless{}0.001 ** \\ EAT End-diastolic area (cm\({}^{2}\)) & 10.4 (\(\pm\)4.8) \(\ddagger\) & 13.9 (\(\pm\)5.7) \(\ddagger\) & 16.5 (\(\pm\)4.9) \# & \textless{}0.001 ** \\ \hline Pericardial Adipose Tissue (PAT) & & & & \\ \hline PAT Area in 4-Chamber view (cm\({}^{2}\)) & 24.9 (\(\pm\)17.6) \(\ddagger\) & 35.2 (\(\pm\)16.6) \(\ddagger\) & 48.1 (\(\pm\)21.7) \# & \textless{}0.001 ** \\ PAT End-systolic area (cm\({}^{2}\)) & 12.8 (\(\pm\)9.8) \(\ddagger\) & 18.9 (\(\pm\)10.7) \(\ddagger\) & 25.6 (\(\pm\)12.2) \# & \textless{}0.001 ** \\ PAT End-diastolic area (cm\({}^{2}\)) & 11.8 (\(\pm\)9.8) \(\ddagger\) & 17.7 (\(\pm\)9.6) \(\ddagger\) & 24.5 (\(\pm\)11.5) \# & \textless{}0.001 ** \\ \hline Total cardiac fat (EAT + PAT) & & & & \\ \hline Total end-systolic area (cm\({}^{2}\)) & 23.6 (\(\pm\)13.8) \(\ddagger\) & 33.6 (\(\pm\)15.6) \(\ddagger\) & 43.1 (\(\pm\)16.2) \# & \textless{}0.001 ** \\ Total end-diastolic area (cm\({}^{2}\)) & 22.1 (\(\pm\)14.12) \(\ddagger\) & 31.6 (\(\pm\)14.5) \(\ddagger\) & 40.9 (\(\pm\)15.2) \# & \textless{}0.001 ** \\ \hline \hline \end{tabular}  
* Variables are expressed as mean \(\pm\) SD. **\(p\)** \(<\) 0.001 assessed by Kruskal–Wallis H test and adjusted using Bonferroni adjustment for multiple comparisons; \(\ddagger\), difference between group 1 and 2, \(p\) \(<\) 0.05; \(\ddagger\), difference between group 2 and 3, \(p\) \(<\) 0.05; and \(\#\), difference between group 1 and 3, \(p\) \(<\) 0.05.  
\end{table} 
Table 2: Cardiac fat parameters in relation to BMI.