Table 1.
Baseline Characteristics of LQTS LP/Pathogenic Carriers and Unaffected Noncarriers
| Characteristic | Carriers | Noncarriers | P value |
|---|---|---|---|
| Total No. | 208 | 215 | |
| Age at test, mean (SD), y | 33 (18) | 36 (19) | 0.05 |
| Male sex, n (%) | 87 (42) | 101 (47) | 0.33 |
| Race or ethnicity, n (%) | <0.001 | ||
| East Asian | 14 (7) | 25 (12) | |
| European ancestry | 143 (69) | 152 (71) | |
| Indigenous | 39 (18) | 4 (2) | |
| KCNQ1 variant, n (%) | 163 (78) | … | … |
| KCNH2 variant, n (%) | 45 (22) | … | … |
| Resting HR, mean (SD), bpm | 68 (13) | 73 (14) | <0.001* |
| Resting QTc, mean (SD), ms | 461 (43) | 407 (33) | <0.001* |
| β‐Blocker use, n (%) | 87 (40) | … | … |
| Symptomatic at baseline, n (%) | 80 (38) | … | … |
| Syncope | 39 | ||
| Chest pain | 19 | ||
| Cardiac arrest | 5 | ||
| Palpitations | 23 | ||
| Presyncope | 17 |
BPM indicates beats per minute; HR, heart rate; LP, likely pathogenic; LQTS, long‐QT syndrome; and QTc, corrected QT interval.
*
Adjusted for age, sex, and familial relatedness.