Use of a spot-check protocol to measure ventricular response rate in dogs with atrial fibrillation: Ventricular rate spot-check protocol in dogs with atrial fibrillation

Abstract

Introduction: Fast ventricular response rates (VRR) have negative prognostic value in atrial fibrillation (AF). Therapeutic recommendations for canine AF rely on measurements of VRR from ambulatory electrocardiograms (aECG). Materials methods: Data from aECG of dogs with AF were prospectively acquired alongside VRR measurements obtained at home using a smartphone-based ECG device between 7:00 and 23:00. From these data, three protocols were outlined: (A) five predetermined spot-checks, (B) three six-hourly spot-checks, and (C) three eight-hourly spot-checks. The performance of the protocols was compared with aECG using mesor, mean and median VRR. The presence of circadian variation was explored using cosinor analysis.Results: Eighteen aECG were analysed, and 14 were used to test the spot-check protocols. The protocols showed moderate to strong correlation with aECG, with protocol B performing best (mean, r=0.84, P=<0.0001, bias -22.96, limits of agreement (LOA) 24.4; median, r=0.90, P=<0.0001, bias -24.48, LOA 22.04). Using a mean VRR < 125 beats per minute (bpm) as cut-off, 10/14 dogs (71.4%) hadinadequate VRR control. All protocols correctly identified these dogs, with protocol A performing best for mean VRR > 140 bpm. Circadian variation in VRR was identified in 17/18 dogs (94%).Limitations: Small population, high prevalence of inadequate VRR, non-standardised treatment, potential measurement artefact, lack of outcome data and precise temporal alignment with aECG recordings.Conclusions: Spot-check protocols offer a practical, affordable alternative to aECG for VRR assessment in dogs with AF. We have established that mean VRR > 140 bpm in the protocol predicts inadequate rate control on aECG