Table 1.
Results of two-way anova testing for independent or interacting effects of genotype and anatomical region on electrophysiological properties, Nav1.5 expression and fibrotic properties*
| Effect of genotype (Scn5a+/− vs. WT) | Effect of anatomical region (RVOT vs. RV) | Presence/absence of interaction | Number (n) of Scn5a+/− hearts | Number (n) of WT hearts | |
|---|---|---|---|---|---|
| VERP | P < 0.001 (Scn5a+/− >WT) | P > 0.05 (NS) | P > 0.05 (NS) | 5 | 17 |
| Conduction velocity from planar fit to LATs (CV†) | |||||
| AVN pacing site | P < 0.01 (Scn5a+/− <WT) | P < 0.01 | P > 0.05 (NS) | 17 | 16 |
| LV base pacing site | P < 0.01 (Scn5a+/− <WT) | P < 0.01 | P > 0.05 (NS) | 10 | 7 |
| LV apex pacing site | P < 0.01 (Scn5a+/− <WT) | P < 0.01 | P > 0.05 (NS) | 11 | 6 |
| Conduction velocity from local vector analysis of LATs (CV*) | |||||
| AVN pacing site | P < 0.001 (Scn5a+/− <WT) | P > 0.05 (NS) | P > 0.05 (NS) | 17 | 14 |
| LV base pacing site | P < 0.0001 (Scn5a+/− <WT) | P < 0.01 (RVOT > RV) | P > 0.05 (NS) | 9 | 7 |
| LV apex pacing site | P < 0.001 (Scn5a+/− <WT) | P > 0.05 (NS) | P > 0.05 (NS) | 12 | 6 |
| Conduction dispersion from local vector analysis of LATs (CD) | |||||
| AVN pacing site | P > 0.05 (NS) | P < 0.001 (RVOT > RV) | P > 0.05 (NS) | 17 | 14 |
| LV base pacing site | P > 0.05 (NS) | P > 0.05 (NS) | P > 0.05 (NS) | 9 | 7 |
| LV apex pacing site | P > 0.05 (NS) | P > 0.05 (NS) | P > 0.05 (NS) | 12 | 6 |
| Western blot: Nav1.5 expression | P < 0.01 (Scn5a+/− <WT) | P > 0.05 (NS) | P > 0.05 (NS) | 5 | 5 |
| Levels of fibrosis | P > 0.05 (NS) | P < 0.001 (RVOT > RV) | P > 0.05 (NS) | 4 | 4 |
AVN, atrioventricular node; RV, right ventricular; RVOT, right ventricular outflow tract; LV, left ventricular; LATs, local activation times.
*
Pacing at the RVOT resulted in higher incidences of arrhythmia in Scn5a+/− than WT hearts (Fisher's exact test: P < 0.01); Pacing at the RV yielded indistinguishable incidences between WT and Scn5a+/−.