Table 1.
Clinical phenotype at baseline and follow-up
| Echocardiographic characteristics | Baseline, n=76 | Follow-up, n=64 | |
| LV hypertrophy | Mean MLVWT, mm (±SD, range) (n=71) | 12.8 (±2.6, 8.0–19.0) | 13.0 (±3.0, 7.0–24.0) |
| Mean MLVWT z-score (±SD) (n=34) | 6.6 (±3.4) | NA* | |
| Pattern of hypertrophy (n=72) | Concentric, n (%) | 65 (90.3) | 58 (90.6) |
| ASH, n (%) | 7 (9.7) | 5 (7.8) | |
| Eccentric, n (%) | 0 | 1 (1.6) | |
| Median maximal LVOT gradient (mm Hg) (IQR) (n=50)/(n=45) | 6 (4–9) | 6 (4–9) | |
| LV end diastolic dimension | Mean LVEDd, mm (±SD, range) (n=56) | 36.0 (±6.2, 25–54) | 37.9 (±6.3) |
| Median LVEDd z-score (IQR) | −1.5 (−2.5 to −0.5) | NA* | |
| Impaired LV systolic function (n=49), n (%) | 6 (12.5) | 3 (6.3) | |
| Impaired LV diastolic function (n=39), n (%) | 6 (15.4) | 6 (18.2) | |
| ECG characteristics | Baseline, n=76 | Follow-up, n=29 | |
| Axis | Normal, n (%) | 33 (82.5) | 19 (70.4) |
| Right, n (%) | 6 (15.0) | 7 (29.2) | |
| Left, n (%) | 0 | 0 | |
| Extreme, n (%) | 1 (2.5) | 1 (3.4) | |
| PR interval | Mean (ms) | 136 (±24.3) | 137.5 (±25.7) |
| Range | 104–200 | 93–200 | |
| Sokolow-Lyon score | Mean±SD (range), mm | 38.5±13.9 (14–67) | 31.5±14.5 (9–70) |
| ≥35 mm, n (%) | 25 (64.1) | 10 (34.5) | |
| Dominant S wave in V4 | n (%) | 11 (27.5) | 7 (24.1) |
| QT interval | Mean (±SD) | 316.1 (46.3) | 322.3 (50.0) |
| Corrected QT interval | Mean Qtc (±) | 375.7 (46.1) | 370.1 (40.3) |
| ≥440 ms, n (%) | 3 (7.3) | 2 (6.9) | |
| T wave inversion | Present, n (%) | 30 (73.2) | 25 (86.2) |
| Location of T wave inversion | Inferior | 4 | 3 |
| Lateral | 2 | 0 | |
| Inferolateral | 20 | 18 | |
| Anterior | 3 | 1 | |
| Anterolateral and inferior | 1 | 3 | |
| ST segment changes | Elevation, n (%) | 5 (12.2) | 6 (20.7) |
| Depression, n (%) | 2 (4.9) | 1 (3.4) | |
| Pathological Q waves | Present, n (%) | 11 (26.8) | 13 (44.8) |
| Location of pathological Q waves | Inferolateral | 5 | 1 |
| Inferior | 6 | 12 | |
ASH = asymmetric septal hypertrophy, LVEDd = Left ventricular end diastolic dimension
*The z-scores for MLVWT were not available for follow-up echocardiograms (missing weight and height data).
LV, left ventricular; LVOT, left ventricular outflow tract; MLVWT, maximal left ventricular wall thickness; NA, not available.