Comparison between invasive and non-invasive measurements of baroreflex sensitivity: Implications for studies on risk stratification after a myocardial infarction

Aims: The ATRAMI (Autonomic Tone and Reflexes After Myocardial Infarction) study has proved the independent prognostic value of baroreflex sensitivity. A limitation of the traditional method of estimating baroreflex sensitivity by phenylephrine, is the need to monitor intra-arterial blood pressure. Our objective was to establish whether this invasive method of monitoring could be superseded by non-invasive methods, such as the Finapres device. Methods and Results: Patients with three repeated invasive and non-invasive baroreflex sensitivity measurements were selected from the ATRAMI database (n=454). The mean of these measurements was taken as the baroreflex sensitivity estimate. The repeatability of both methods (standard deviation of the three measurements) decreased with increasing baroreflex sensitivity. There was no constant bias between invasive and non-invasive measurements (0.22 ± 2.2 ms . mmHg^-1, P=0.42). The linear correlation was very high (r=0.91, P