Table 5.
ROC curve statistics for RMSSD to predict the presence of arrhythmia (including only horses with arrhythmias occurring in each separate phase)
| Phase AUC (95% CI) P‐value | RMSSD cutoff | Sn (%) (95% CI) | Sp (%) (95% CI) | LR | |
|---|---|---|---|---|---|
| Trot 0.82 (0.55‐1.1) P = .01 | High Sn | 3.7 | 100 (54%‐100%) | 10 (3.5%‐23%) | 1.1 |
| Youden index | 6.7 | 83 (36%‐100%) | 83 (70%‐93%) | 5 | |
| High Sp | 8.8 | 67 (22%‐96%) | 98 (89%‐100%) | 32 | |
| Canter 0.72 (0.54‐0.91) P = .04 | High Sn | 4.6 | 100 (63%‐100%) | 33 (20%‐48%) | 1.5 |
| Youden index | 6.7 | 63 (24%‐91%) | 72 (57%‐84%) | 2.2 | |
| High Sp | 12 | 25 (3.2%‐65%) | 98 (88%‐100%) | 12 | |
| Recovery 0.98 (0.95‐1) P < .0001 | High Sn | 5.2 | 100 (86%‐100%) | 67 (47%‐83%) | 3 |
| Youden index | 6.4 | 96 (79%‐100%) | 93 (78%‐99%) | 14 | |
| High Sp | 7.3 | 83 (63%‐95%) | 97 (83%‐100%) | 25 |
Abbreviations: AUC, area under curve; LR, likelihood ratio; RMSSD, square root of mean‐squared differences in successive R‐R intervals; ROC curve, receiver operating characteristic curve; Sn, sensitivity; Sp, Specificity.