Table 1.
Heart rate, sinus pauses, and AV block in unrestrained mice at baseline and effect of acute and chronic interventions
| Baseline |
Propranolol |
|||
|---|---|---|---|---|
| WT | ΔKPQ-SCN5A | WT | ΔKPQ-SCN5A | |
| Mean heart rate (HR) 24 h | 548 ± 47(16) | 498 ± 52*(18) | 489 ± 33***(13) | 474 ± 40*,***(15) |
| HR variability SD-HR | 76 ± 15(16) | 86 ± 15(18) | 57 ± 13***(13) | 64 ± 14***(15) |
| HR 10 am - 6 pm (at rest) | 505 ± 20**(16) | 451 ± 24*,**(18) | 464 ± 20**,***(13) | 446 ± 22*,**(15) |
| HR swim stress | 705 ± 35**(10) | 677 ± 22*,**(13) | 555 ± 54**,***(10) | 539 ± 32**,***(13) |
| HR air jet stress | 678 ± 35**(10) | 640 ± 44*,**(13) | 583 ± 37**,***(10) | 550 ± 57**,***(13) |
| HR isoproterenol i.p. | 725 ± 41**(11) | 694 ± 35*,**(14) | 699 ± 71**(4) | 710 ± 26**(4) |
| HR atropine i.p. | 641 ± 42**(3) | 612 ± 68**(6) | no value | no value |
| HR carbachol i.p. | 223 ± 38**(7) | 230 ± 51**(9) | 190 ± 21**(4) | 240 ± 46**(4) |
| HR carbachol i.p. prior ES | 207 ± 40**(4) | 210 ± 54**(8) | 180 ± 24**(4) | 207 ± 43**(6) |
| AVB or pauses/5 min/24 h | 1.4 ± 1.3(6) | 3.1 ± 1.8*(6) | 1.7 ± 1.4(6) | 2.5 ± 1.4*(6) |
| Max pause (ms cycle length) | 227(6) | 601(6) | 489(5) | 993(6) |
Mean ± SD of heart rates (n of mice in brackets) in unrestrained ΔKPQ-SCN5A and littermate WT mice at baseline and during chronic oral propranolol treatment. Pauses or AV block numbers were determined as mean of 24 5-min-time periods over 24 consecutive hours per animal.
b.p.m., beats per minute; HR, variability SD-HR standard deviation of heart rate; i.p., intraperitoneal (time 2–12 min after i.p. injection was analysed, only sinus beats counted); ES, extrasystole (10 beats prior to first ES or arrhythmia analysed); AVB, atrioventricular block.
*P < 0.05 ΔKPQ-SCN5A vs. WT.
**P < 0.05 heart rate vs. respective 24 h heart rate.
***P < 0.05 baseline vs. propranolol.