Introduction: Carotid artery applanation tonometry is widely used to assess carotid-femoral pulse wave velocity and the local carotid artery pressure waveform. However, the substantial pressure applied locally to the carotid artery with applanation tonometry, might evoke a baroreceptor response. This response would lead to changes in heart rate (HR) and blood pressure waveforms, influencing the intended measurements. In this study, we assessed whether carotid applanation tonometry has an influence on HR.

Methods: In 22 hypertensive subjects, HR was assessed during carotid as well as femoral applanation tonometry by continuous finger pulse waveform recording (Nexfin). Subjects were in supine position. Both carotid and femoral acquisitions were measured in alternation and in triplicate. Median averaging over the three measurements was used to obtain a subject’s median HR during carotid as well as femoral tonometry.

Results: HR during carotid tonometry and femoral tonometry was 64.0±9.3bpm and 64.6±9.0bpm, respectively. Difference (carotid-femoral) was −0.7±2.4bpm (p=0.198, two-sided t-test, 95% CI: [−1.7,0.4]bpm). Given a power (1-β) of 0.8 and α=0.05, our study was powered to statistically detect a 1.4bpm HR difference.

Conclusion: We conclude that carotid artery tonometry influences HR by at most 1.4bpm, which appears clinically insignificant.