Table 1. Baseline Characteristics of the Study Cohort.
| Characteristic | Patient Data (n = 13)a |
|---|---|
| Age, median (IQR), y | 16 (15.0-22.5) |
| Male | 7 (54) |
| White | 12 (92) |
| Hispanic | 1 (8) |
| Putative pathogenic mutation | 11 (85) |
| RYR2 | 10 (77) |
| CASQ2 | 1 (8) |
| Weight, median (IQR), kg | 74.5 (54-86) |
| Height, median (IQR), cm | 168 (157-180) |
| β-Blocker useb | 13 (100) |
| Nadolol | 9 (69) |
| Atenolol | 2 (15) |
| Metoprolol succinate | 1 (8) |
| Propranolol hydrochloride | 1 (8) |
| Exercise score at baselinec | |
| 0 | 3 (23) |
| 1 | 0 (0) |
| 2 | 1 (8) |
| 3 | 6 (46) |
| 4 | 3 (23) |
Abbreviations: CASQ2, cardiac calsequestrin gene; IQR, interquartile range; RYR2, ryanodine receptor 2 calcium release channel gene.
a
Unless otherwise indicated, data are expressed as number (percentage) of patients.
b
β-Blocker use was unchanged throughout the trial. For nadolol, median daily dose was 80 mg; for atenolol, median daily dose was 112 mg; for metoprolol succinate, daily dose was 50 mg; and for propranolol hydrochloride, daily dose was 240 mg.
c
Scores are for β-blocker treatment alone, with 0 indicating no ectopy; 1, isolated premature ventricular contractions; 2, bigeminy; 3, couplets; and 4, nonsustained ventricular tachycardia.