Table 1

Clinical phenotype at baseline and follow-up

Echocardiographic characteristicsBaseline, n=76Follow-up, n=64
LV hypertrophyMean 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 (%)01 (1.6)
Median maximal LVOT gradient (mm Hg) (IQR) (n=50)/(n=45)6 (4–9)6 (4–9)
LV end diastolic dimensionMean 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 characteristicsBaseline, n=76Follow-up, n=29
AxisNormal, n (%)33 (82.5)19 (70.4)
Right, n (%)6 (15.0)7 (29.2)
Left, n (%)00
Extreme, n (%)1 (2.5)1 (3.4)
PR intervalMean (ms)136 (±24.3)137.5 (±25.7)
Range104–20093–200
Sokolow-Lyon scoreMean±SD (range), mm38.5±13.9 (14–67)31.5±14.5 (9–70)
≥35 mm, n (%)25 (64.1)10 (34.5)
Dominant S wave in V4n (%)11 (27.5)7 (24.1)
QT intervalMean (±SD)316.1 (46.3)322.3 (50.0)
Corrected QT intervalMean Qtc (±)375.7 (46.1)370.1 (40.3)
≥440 ms, n (%)3 (7.3)2 (6.9)
T wave inversionPresent, n (%)30 (73.2)25 (86.2)
Location of T wave inversionInferior43
Lateral20
Inferolateral2018
Anterior31
Anterolateral and inferior13
ST segment changesElevation, n (%)5 (12.2)6 (20.7)
Depression, n (%)2 (4.9)1 (3.4)
Pathological Q wavesPresent, n (%)11 (26.8)13 (44.8)
Location of pathological Q wavesInferolateral51
Inferior612
  • 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.