Table 3.
ECG intervals and intracardiac ECG parameters in anaesthetized NPR-C+/+ and NPR-C−/− mice
| NPR-C+/+ | NPR-C−/− | P value | |
|---|---|---|---|
| Heart rate (beats min–1) | 568 ± 9 | 587 ± 12 | 0.228 |
| R-R interval (ms) | 106.1 ± 1.6 | 103.1 ± 2.1 | 0.438 |
| P wave duration (ms) | 14.1 ± 0.4 | 13.0 ± 0.3 | 0.117 |
| P-R interval (ms) | 37.6 ± 0.7 | 38.6 ± 0.6 | 0.268 |
| QRS duration (ms) | 11.7 ± 0.4 | 12.7 ± 0.4 | 0.189 |
| Q-T interval (ms) | 40.5 ± 0.9 | 38.7 ± 0.9 | 0.284 |
| Q-Tc interval (ms) | 124.4 ± 2.5 | 120.5 ± 2.2 | 0.393 |
| cSNRT100 (ms) | 36.1 ± 2.0 | 47.1 ± 5.2* | <0.001 |
| AERP (ms) | 32.8 ± 1.4 | 41.0 ± 2.6* | 0.011 |
| AVERP (ms) | 49.5 ± 3.3 | 51.0 ± 1.9 | 0.066 |
| VERP (ms) | 48.5 ± 4.7 | 46.2 ± 5.8 | 0.768 |
Data are means ± SEM; n = 20 NPR-C+/+ mice and 16 NPR-C−/− mice for all measurements except VERP where n = 8 NPR-C+/+ mice and 9 NPR-C−/− mice. *P < 0.05 vs. NPR-C+/+ by Student's t test. Abbreviations: AERP, atrial effective refractory period; AVERP, atrioventricular node effective refractory period; cSNRT, corrected sinoatrial node recovery time; NPR, natriuretic peptide receptor; VERP, ventricular effective refractory period. P-R interval was measured from the start of the P wave to the peak of the QRS complex. Q-T interval was measured from the start of the QRS complex to the end of the T wave. Q-Tc, HR corrected Q-T interval.