TABLE 2.
Comparisons of bimodal versus singular histogram distributions within dog and clustered versus branched beat-to-beat interval patterns between dogs.
| (A) Within dog (n = 128) (paired data) comparison of an hour with a large paucity of beats resulting in a bimodal distribution and an hour with a small paucity of beats characterized as a single distribution. Heart rate variability parameters corrected for heart rate (see text). Data shown as median (range) and p-value from Wilcoxon Signed Rank Test with Bonferroni correction. | |||
| Parameter | Bimodal | Singular | p-value |
| Average heart rate (bpm) | 68(50−130) | 110(75−163) | <0.001 |
| Beat-to-beat interval (ms) | 882(462−1200) | 546(368−800) | <0.001 |
| Minimum heart rate (bpm) | 48(32−139) | 69(34−108) | <0.001 |
| Maximum heart rate (bpm) | 147(80−236) | 199(123−313) | <0.001 |
| SDNN (ms) | 0.38(0.22−0.58) | 0.27(0.07−1.35) | <0.001 |
| SDANNIn (ms) | 0.34(0.15−0.49) | 0.20(0.05−0.55) | <0.001 |
| SDANN (ms) | 0.11(0.03−0.50) | 0.16(0.03−0.59) | 0.032 |
| RMSSD (ms) | 0.47(0.18−0.69) | 0.24(0.04−0.57) | <0.001 |
| Frequency domain total power (ms2) | 24486(1379−66913) | 4493(335−31063) | <0.001 |
| Frequency domain HRV-HF (ms2) | 19311(33−59924) | 312(14−10770) | <0.001 |
| (B) Comparison of beat patterning (clustered versus branched) during a single sleep hour in 50 dogs (13/12 boxers/non-boxers each group). Heart rate variability parameters corrected for rate/interval (see text). Data shown as median (range) and p-value from Wilcoxon Test with Bonferroni correction. | |||
| Clustered (n = 25) | Branched (n = 25) | p-value | |
| Average heart rate (bpm) | 71(57−93) | 54(46−92) | <0.001 |
| Beat-to-beat interval (ms) | 845(645−1053) | 1111(652−1304) | <0.001 |
| Minimum heart rate (bpm) | 55(42−68) | 41(34−71) | <0.001 |
| Maximum heart rate (bpm) | 144(103−196) | 137(112−174) | 0.99 |
| Number of pauses | 1(0−16) | 24(0−374) | 0.006 |
| SDNN (ms) | 0.349(0.156−0.468) | 0.409(0.273−0.467) | 0.008 |
| SDANNIn (ms) | 0.312(0.128−0.424) | 0.369(0.245−0.426) | 0.02 |
| SDANN (ms) | 0.099(0.049−0.205) | 0.118(0.038−0.226) | 0.36 |
| RMSSD (ms) | 0.477(0.167−0.619) | 0.481(0.373−0.686) | 0.99 |
| Frequency domain total power (ms2) | 19036(6352−59061) | 33541(11492−86423) | <0.001 |
| Frequency domain HRV-HF (ms2) | 15856(4107−55894) | 19741(5205−44501) | 0.2 |