Baseline characteristics of patient subgroups based on initial symptoms presented
| Feature | Initial asymptomatic (n=315) | Initial syncope (n=159) | Initial VT/VF (n=42) | P value |
| Female | 22 (6.98) | 15 (9.43) | 2 (4.76) | 0.567 |
| Age of initial presentation | 51.0±15.8 | 49.0±16.5 | 45.8±17.9 | 0.113 |
| Follow-up period (months) | 85.5±52.8 | 88.0±52.0 | 89.4±63.1 | 0.873 |
| Initial type 1 BrP | 202 (64.1) | 95 (59.7) | 22 (52.4) | 0.280 |
| Type 1 BrP | 247 (78.4) | 114 (71.7) | 27 (64.3) | 0.065 |
| Evolution | 117 (37.1) | 47 (29.2) | 13 (31.0) | 0.236 |
| Fever induced | 59 (18.7) | 17 (10.7) | 3 (7.14) | 0.024 |
| Family history of BrS | 13 (4.13) | 2 (1.26) | 1 (2.38) | 0.211 |
| Family History of VF/SCD | 26 (8.25) | 12 (7.55) | 3 (7.14) | 0.967 |
| Syncope | 35 (11.1) | 159 (100) | 28 (66.7) | <0.0001 |
| Number of syncope | 1.37±21.6 | 2.01±2.56 | 0.905±0.821 | <0.0001 |
| VT/VF | 13 (4.13) | 25 (15.7) | 42 (100) | <0.0001 |
| Number of VT/VF episodes | 0.302±3.14 | 1.39±7.86 | 8.10±14.7 | <0.0001 |
| Mean VT/VF event rate ratio per person-year, % | 0.010 | 0.048 | 1.70 | <0.0001 |
| High VT/VF burden | 3 (0.952) | 12 (7.55) | 22 (52.4) | <0.0001 |
| Drug challenge performed | 121 (38.4) | 82 (51.6) | 22 (52.4) | 0.012 |
| Drug positive* | 109 (90.1) | 72 (87.8) | 17 (77.3) | 0.245 |
| EPS performed | 50 (15.9) | 53 (33.3) | 9 (21.4) | <0.0001 |
| EPS positive* | 28 (56.0) | 38 (73.6) | 9 (100) | 0.014 |
| ICD | 35 (11.4) | 66 (41.5) | 34 (81.0) | <0.0001 |
| Holter performed | 89 (28.3) | 44 (27.7) | 7 (16.7) | 0.285 |
| Abnormal Holter* | 36 (40.4) | 21 (47.7) | 4 (57.1) | 0.531 |
| Other arrhythmias† | 39 (12.7) | 28 (17.6) | 12 (28.6) | 0.022 |
| Genetic test performed | 27 (8.60) | 15 (9.43) | 9 (21.4) | 0.052 |
| Genetic test positive* | 9 (33.3) | 4 (16.0) | 3 (33.3) | 0.922 |
| Treadmill performed | 41 (13.0) | 18 (11.3) | 4 (9.52) | 0.794 |
| Echocardiogram performed | 138 (43.8) | 73 (45.9) | 26 (66.7) | 0.020 |
| EEG performed | 13 (4.13) | 33 (20.1) | 12 (28.6) | <0.0001 |
| EEG positive | 3 (23.1) | 5 (15.2) | 8 (66.7) | <0.0001 |
P-values less than 0.05 are shown in bold text.
*Indicates the patient percentage within the subgroup population where the investigation is performed
†Other arrhythmias include sick sinus syndrome, bradycardia, atrioventricular block, atrial tachyarrhythmias and supraventricular tachyarrhythmias.
BrP, Brugada pattern; BrS, Brugada syndrome; EEG, electroencephalogram; EPS, electrophysiological study; ICD, implantable cardioverter-defibrillator; SCD, sudden cardiac death; VF, ventricular fibrillation; VT, ventricular tachycardia.