Table 1 Clinical characteristics of investigated individuals, members of 10 unrelated families.

From: Long-QT founder variant T309I-Kv7.1 with dominant negative pattern may predispose delayed afterdepolarizations under β-adrenergic stimulation

All individuals (n = 54)

 

T309I + (n = 30)

T309I- (n = 24)

Age (years)

30.0 ± 20.2

32.2 ± 20.1

Females

25 (83.3%)

13 (54.2%)

Individuals with completed clinical investigation (n = 41)

 

T309I + (n = 24)

T309I- (n = 17)

Age (years)

26.3 ± 18.4

30.1 ± 15.6

Females

20 (83.3%)

9 (52.9%)

Children under 16 years

10

3

Syncope/ACA

4/2

0/0

QTc, rest (ms)

466 ± 24†††

418 ± 20

QTc, rest—children (ms)

465 ± 27††

410 ± 10

QTc, rest—adults (ms)

466 ± 22†††

420 ± 21

QTc, recovery (ms)

508 ± 32***†††

417 ± 24

QTc, recovery—children (ms)

510 ± 40**†

425 ± 7

QTc, recovery—adults (ms)

508 ± 27***†††

416 ± 25

  1. T309I + , T309I carriers; T309I-, T309I non-carriers; mean ± SD, n—number of individuals; QTc, QT interval corrected to the heart rate (Bazett´s formula); QTc, recovery, QTc, 4th minute of the recovery phase after ergometry; ACA, aborted cardiac arrest; statistics in the respective groups of patients (all/children/adults): ** and ***—statistical significance of QTc difference at rest and during recovery at P < 0.01 and 0.001, respectively, †, †† and †††—statistical significance of the respective QTc difference between T309I + and T309I- at P < 0.05, 0.01 and 0.001, respectively.
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