Cardiovascular Journal of Africa: Vol 32 No 6 (NOVEMBER/DECEMBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 6, November/December 2021 294 AFRICA Patients in group I were significantly younger, more symptomatic and more of them had inducible AF in EPS (Table 2). Furthermore, when patients were grouped into two groups, according to having inducible AF or not, individuals who experience AF episodes ( n = 30) had significantly shorter PDI (91.3 ± 7.9 vs 101.3 ± 8.1, p < 0.001). It was similar when the study group was divided into two according to symptom status; symptomatic patients ( n = 57) had significantly shorter PDI than the others (96.4 ± 9.79 vs 100.93 ± 8.03, p = 0.012). Spearman correlation analysis (Fig. 2) revealed a positive and moderate correlation between PDI and APERP ( r = 0.598, p < 0.001), a positive and moderate correlation between PDI and age ( r = 0.800, p < 0.001), a negative and moderate correlation between PDI and inducible AF ( r = –0.492, p < 0.001), a positive and moderate correlation between age and APERP ( r = 0.552, p < 0.001), a negative and moderate correlation between age and inducible AF ( r = –0.445, p < 0.001), and a negative and moderate correlation between APERP and inducible AF ( r = –0.425, p < 0.001). Univariate analysis showed that PDI was an independent predictor of APERP (OR: 1.211, 95% CI: 1.076–1.363; p = 0.002). In the ROC curve analysis, the value for PDI to detect APERP ≥ 240 ms with a sensitivity of 80% and a specificity of 83% was 90.5 (the area under the curve was 0.85, p < 0.001). The best cut-off value for PDI to detect AF triggering tachycardia was 110.5, with a sensitivity of 97% and a specificity of 83% (the area under the curve was 0.187, p < 0.001) (Fig. 3). Discussion We found that the non-invasive electrocardiographic PDI parameter was correlated with invasive risk-stratification parameters. Its use may provide additional information as an easily applicable non-invasive ECG parameter. In 1913, Kent demonstrated that AV connection was not singular and limited to the AV node. 6,7 In 1930, Wolff, Parkinson and White described a distinct pattern of surface ECG with short PR interval and right bundle branch block (RBBB) 1-specificity Sensitivity: 97% specificity: 83% AUC: 0.187 p < 0.001 1.0 0.8 0.6 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Sensitivity 1-specificity Sensitivity: 80% specificity: 83% AUC: 0.85 p < 0.001 1.0 0.8 0.6 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Sensitivity Fig. 3. A: ROC curve for P- to delta-wave interval to detect AF inducibility. B: ROC curve for P- to delta-wave interval to detect APERP ≥ 240 ms. Age APERP PDI Inducible AF Age APERP PDI Inducible AF Fig. 2. Correlation matrix. AF: atrial fibrillation, APERP: accessory pathway antegrade effective refractory period, PDI: P- to delta-wave interval. Table 2. Comparison of patients by APERP Parameter APERP < 240 ms ( n = 29) APERP ≥ 240 ms ( n = 74) p -value Age, years 31.38 ± 10.8 47.08 ± 13.1 0.000 Male gender, n (%) 5 (17.2) 27 (36.5) 0.059 Hypertension, n (%) 1 (3.4) 2 (2.7) 0.840 Diabetes, n (%) 0 6 (8.1) 0.116 Structural heart disease, n (%) 4 (13.8) 1 (1.4) 0.09 Symptomatic patients, n (%) 27 (93.1) 30 (40.5) 0.012 PDI, ms 89.8 ± 6.3 101.8 ± 8.0 0.000 AF triggering tachyardia, n (%) 16 (55.2) 14 (18.9) 0.000 AF: atrial fibrillation, APERP: accessory pathway antegrade effective refractory period, PDI: P- to delta-wave interval. A B