Table 3.
Peri‐ictal electrocardiographic findings in the Dravet syndrome and historical epilepsy control group.
|
Dravet syndrome n = 45 subjects |
Controls n = 90 subjects |
P‐value | 95% CI of OR | |
|---|---|---|---|---|
| Seizure types, n seizures (%) | ||||
| Total number of seizures | 547 | 169 | NA | NA |
| Convulsive | 300 (55) | 120 (71) | NA | NA |
| Tonic | 33 (6) | 29 (17) | NA | NA |
| Focal impaired awareness | 12 (2.2) | 18 (11) | NA | NA |
| Focal motor | 9 (1.6) | 0 | NA | NA |
| Hemiclonic | 7 (1.3) | 2 (1.2) | NA | NA |
| Clonic | 1 (0.2) | 0 | NA | NA |
| Unknown type reported | 41 (7.5) | 0 | NA | NA |
| Unreported | 144 (6) | 0 | NA | NA |
| Peri‐ictal ECG variables, n seizures (n people; %) | ||||
| Bradycardia, n seizures (n subjects; %) | 4 (2; 0.7) | 11 (8; 6.5) | 0.002 | 1.2 to 5.3 |
| Prolonged QTc, n seizures (n subjects; %) | 1 (1; 0.2) | 1 (1; 0.6) | 0.7 1 | −0.99 to 2.8 |
| T1 | 0 | 0 | ||
| T2 | 0 | 1 | ||
| T3 | 1 | 0 | ||
| T4 | 1 | 0 | ||
| Shortened QTc, n seizures (n subjects; %) | 31 (12; 5.7) | 12 (12; 7.1) | 0.82 1 | −0.72 to 0.92 |
| T1 | 17 | 5 | ||
| T2 | 5 | 4 | ||
| T3 | 10 | 3 | ||
| T4 | 5 | 2 | ||
| Ictal QTc‐lengthening, ≥60 ms compared to T1, n seizures (n subjects; %) | 64 (23; 12) | 8 (8; 4.7) | 0.048 1 | −1.7 to −0.21 |
| T2 | 53 | 4 | ||
| T3 | 4 | 1 | ||
| T4 | 9 | 3 | ||
| Ictal QTc‐shortening, ≥60 ms compared to T1, n seizures (n subjects; %) | 15 (7; 2.7) | 13 (11; 7.7) | 0.39 1 | −0.26 to 2 |
| T2 | 12 | 10 | ||
| T3 | 3 | 5 | ||
| T4 | 2 | 4 | ||
CI, confidence interval; OR, odds ratio; T1, time of seizure onset; T2, seizure end; T3, 2 min after seizure end; T4, 5 min after seizure end.
1
The Holm–Bonferroni method was used to correct for the multiple comparisons of the QTc‐interval; corrected p‐values and original CIs are shown. Generalized estimating equations were used to correct for within‐subject correlation, seizure onset from sleep or wakefulness and seizure type (convulsive seizure yes or no). QTc changes can occur at multiple time points within seizures.