Table 2.
Clinical characteristics of patients based on genotype
| LQT1 n = 207 |
LQT2 n = 175 |
p | |
|---|---|---|---|
| Symptoms prior to therapy, n (%) | 56 (27) | 45 (26) | 0.8 |
| Baseline HR, bpm | 77 ± 15 | 74 ± 16 | 0.08 |
| Baseline QTc, ms | 467 ± 42 | 478 ± 50 | 0.01 |
| Median age at start of BB (IQR), years | 12 (7–30) | 18 (10–34) | 0.04 |
| ΔHR, bpm | 11 ± 12 | 11 ± 12 | 0.9 |
| ΔQTc, ms | 18 ± 32 | 18 ± 37 | 0.9 |
| ΔQTc with propranolol, ms | 25 ± 35 | 29 ± 43 | 0.6 |
| ΔQTc with metoprolol, ms | 16 ± 29 | 12 ± 37 | 0.5 |
| ΔQTc with nadolol, ms | 11 ± 30 | 14 ± 22 | 0.6 |
BB, beta-blocker; HR, heart rate; IQR, interquartile range; Δ, change in ECG parameter with BB initiation