Table 2.
Univariate predictors of postdiagnosis VT/VF-free survival
| Predictor | Overall | Adult | ||||
| HR | 95% CI | P value | HR | 95% CI | P value | |
| Female | 1.13 | (0.568 to 2.25) | 0.730 | 1.37 | (0.518 to 3.60) | 0.529 |
| Onset age | 1.01 | (0.997 to 1.02) | 0.146 | 0.992 | (0.963 to 1.02) | 0.573 |
| Family history of LQTS | 0.359 | (0.163 to 0.794) | 0.011 | 0.427 | (0.154 to 1.19) | 0.103 |
| Family history of SCD | 0.148 | (0.020 to 1.08) | 0.060 | 0.162 | (0.022 to 1.22) | 0.077 |
| Initial asymptomatic | 0.301 | (0.136 to 0.662) | 0.003 | 0.357 | (0.129 to 0.986) | 0.047 |
| Initial syncope | 0.721 | (0.345 to 1.50) | 0.383 | 1.08 | (0.411 to 2.83) | 0.878 |
| Initial VT/VF | 5.80 | (2.94 to 11.5) | <0.0001 | 2.82 | (1.14 to 7.03) | 0.026 |
| Initial QTc interval | 1.01 | (1.00 to 1.02) | 0.007 | 1.01 | (0.997 to 1.01) | 0.227 |
| Positive treadmill test | 0.086 | (0.009 to 0.793) | 0.030 | / | / | / |
| Positive EPS | 0.377 | (0.039 to 3.63) | 0.399 | 1.09 | (0.089 to 13.3) | 0.948 |
| Arrhythmia in Holter Study | 1.10 | (0.330 to 3.67) | 0.877 | 0.449 | (0.075 to 2.69) | 0.381 |
| Other arrhythmias | 4.50 | (2.32 to 8.74) | <0.0001 | 4.49 | (1.85 to 10.9) | 0.001 |
| Schwartz Score | 1.49 | (1.08 to 2.05) | 0.015 | 3.76 | (1.70 to 8.34) | 0.001 |
| Follow-up duration | 0.999 | (0.993 to 1.00) | 0.634 | 0.999 | (0.992 to 1.01) | 0.787 |
| Baseline ECG characteristics | ||||||
| Heart rate | 1.00 | (0.987 to 1.02) | 0.743 | 1.01 | (0.983 to 1.03) | 0.562 |
| P-wave duration | 0.988 | (0.946 to 1.03) | 0.571 | 0.998 | (0.959 to 1.04) | 0.932 |
| PR interval | 1.00 | (0.985 to 1.02) | 0.754 | 1.00 | (0.981 to 1.03) | 0.809 |
| QRS interval | 1.03 | (1.01 to 1.04) | 0.001 | 1.03 | (1.01 to 1.04) | 0.002 |
| QT interval | 1.00 | (0.997 to 1.01) | 0.359 | 1.00 | (0.995 to 1.01) | 0.500 |
| QTc interval | 1.02 | (1.01 to 1.02) | <0.001 | 1.01 | (1.00 to 1.02) | 0.062 |
| P axis | 0.998 | (0.988 to 1.01) | 0.737 | 0.994 | (0.982 to 1.01) | 0.383 |
| QRS axis | 1.00 | (0.995 to 1.01) | 0.494 | 1.00 | (0.994 to 1.01) | 0.620 |
| T axis | 1.00 | (0.994 to 1.01) | 0.705 | 0.998 | (0.990 to 1.01) | 0.695 |
| Lead V5 R wave amplitude | 1.15 | (0.587 to 2.26) | 0.680 | 0.761 | (0.371 to 1.56) | 0.456 |
| Lead V1 S wave amplitude | 2.09 | (0.699 to 6.26) | 0.187 | 1.73 | (0.556 to 5.37) | 0.344 |
| First degree AV block | 1.92 | (0.440 to 8.39) | 0.386 | 3.91 | (0.770 to 19.9) | 0.100 |
| Interventricular delay | 3.11 | (1.37 to 7.08) | 0.007 | 3.60 | (1.38 to 9.41) | 0.009 |
EPS, electrophysiological study; LQTS, long QT syndrome; LQTS, long QT syndrome; SCD, sudden cardiac death; VT/VF, ventricular tachycardia/ventricular fibrillation.