Table 2.
ECG characteristics of Scn1b wildtype, null, and heterozygous mice.
| CONTROL | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| n | P duration (ms) | QRS (ms) | PR (ms) | QTPeak (ms) | QT90 (ms) | RR (ms) | R-amp (mV) | QT90C (ms) | |
| WT | 27 | 10.61±0.33 | 8.62± 0.32 | 46.60±1.58 | 17.41±0.61 | 27.23±0.96 | 162.1±5.5 | 1.49±0.07 | 19.3±0.07 |
| Null | 29 | 10.39±0.32 | 8.98± 0.29 | 49.18±1.57† | 20.87±0.58* | 32.42±0.99* | 181.8±5.7* | 1.46±0.07 | 33.12±0.10 |
| Het | 48 | 10.00±0.32 | 8.67± 0.22 | 46.22±0.96 | 17.66±0.41 | 27.57±0.63 | 163.3±3.2 | 1.58±0.05 | 22.2±0.08 |
| PROPRANOLOL & ATROPINE | |||||||||
| n | P duration (ms) | QRS (ms) | PR (ms) | QTPeak (ms) | QT90 (ms) | RR (ms) | R-amp (mV) | QT90C (ms) | |
| WT | 8 | 11.81±0.5§ | 10.20±0.8¢ | 48.51±2. 5 | 20.24±1.3¢ | 28.66±1.3 | 174.2±6.8 | 1.37±0.07 | 16.61±0.1 |
| Null | 10 | 11.34±0.6¢ | 9.58±0.5¢ | 47.57±1.4 | 23.91±0.9¢* | 35.41±1.0* | 205.5±4.7§* | 1.30±0.08 | 43.82±0.3 |
| Het | 13 | 11.64±0.3§ | 10.74±0.6¢ | 45.94±1.5 | 20.38±0.6¢ | 28.92±0.9 | 171.9±7.4 | 1.33±0.08 | 23.34±0.1 |
ECG data are tabulated before (control) and after autonomic block. P represents the duration of the P wave, while QTPEAK represents the interval from the onset of the Q wave to the peak of the T wave. QT90 is the time duration from Q to 90% decay of the T wave from peak to baseline. QT90C represents the QT90 duration corrected for heart rate [24]. R-amp denotes the amplitude of the R wave. Data were analyzed as described in Methods (Investigator 1).
p ≤ 0.05 for Scn1b null (Null) vs. both Scn1b wildtype (WT) and Scn1b heterozygous (Het) mice, with p > 0.1 for WT vs. Het.
p ≤ 0.1 for Null vs. Het only, with p > 0.1 for both Null vs. WT, and WT vs. Het.
p ≤ 0.05
p ≤ 0.1 for control vs. propranolol and atropine recordings.
Similar results (not shown) were observed using an alternative analysis protocol (Methods, Investigator 2), which also included measurements of (control) heart rate corrected Q to end of T interval (QT100c); Scn1b wildtype = 50.40 ± 0.17 ms n = 26, Scn1b null =79.04 ± 0.19 ms n = 30, Scn1b heterozygous = 44.93 ± 0.23 ms n = 41.