How to estimate heart rate from pulse rate reported by oscillometric method in atrial fibrillation: The value of pulse rate variation.

Objectives: To evaluate whether the mean pulse rate (PR) from three oscillometric blood pressure (BP) measurements provides an accurate estimation of electrocardiogram ventricular rate (HR) in patients with permanent atrial fibrillation (AF).

Methods: BP and PR were measured with an oscillometric BP device for three times with one-minute interval. Simultaneously, one-minute electrocardiogram was also recorded for three times. The first PR and HR values were recorded as PR1 and HR1, and the averages of three PR and HR values as mean PR (mPR) and mean HR (mHR). Meanwhile, the differences between the highest and lowest values among the three PR and HR were calculated as ΔPR and ΔHR. Furthermore, the patients were stratified on ΔPR into the 0-15 and >15 subgroups.

Results: A moderate positive correlation existed between PR1 and HR1 or mPR and mHR, and Bland-Altman plot also showed quite wide 95% limits between them. Meanwhile, ΔPR was significantly higher than ΔHR (12.1±8.6 vs 3.6±2.5bpm, P<0.001). However, in the 0-15 subgroup, the correlation between mPR and mHR was high (R2=0.800), and the 95% limits were only from -11.3 to 14.2bpm with a difference of 1.4bpm. The coincidence (mPR-mHR<10bpm) rate was 93.9% when PR≤80bpm, 96.3% when PR 81-100bpm, and 88.9% when PR over 100bpm.

Conclusion: The average of three PR values reported by an oscillometric BP device could provide a clinically accepted estimation of mean HR of 3min in AF patients with ΔPR 0-15bpm and mean PR ≤100bpm.