Evaluation of in-hospital electrocardiography versus 24-hour Holter for rate control in dogs with atrial fibrillation

ObjectivesTo determine if the in-clinic ECG-derived heart rate could predict the at-home Holter-derived 24-hour average heart rate (Holter(24h)), and whether it is useful to identify slow versus fast atrial fibrillation in dogs. Materials and Methods82 pairs of 1-minute ECGs and 24-hour Holter recordings were acquired in 34 dogs with atrial fibrillation. The initial 24-hour Holter was used to test if the ECG heart rate can identify dogs with slow versus fast atrial fibrillation based on a Holter(24h) threshold value of 140bpm. ResultsECG heart rate overestimated Holter(24h) by 26bpm (95% CI: 3bpm, 48bpm; P<0015) with a 95% limit of agreement of -21 to 83bpm. The in-clinic ECG-derived heart rate A155 bpm had a sensitivity of 73% and a specificity of 100% for identifying a Holter(24h) HR A140 bpm; an in-clinic ECG-derived HR <160bpm had a sensitivity and specificity of 91% each. Clinical SignificanceIn-clinic ECG assessment of heart rate in dogs with atrial fibrillation does not reliably predict the heart rate in their home environment. However, an in-clinic heart rate greater than 155bpm is useful in identifying fast atrial fibrillation, allowing clinicians to stratify which case may benefit from antiarrhythmic therapy.