Baroreflex Sensitivity Estimation by the Transfer Function Method Revised: Effect of Changing the Coherence Criterion

In this study we appraised three new criteria for the computation of baroreflex sensitivity (BRS) using the transfer function magnitude (TFM) method, with the aim of overcoming the conventional requirement of a coherence ≥ 0.5 between arterial pressure and RR interval time series. Measurements were carried out in a sample of 44 post-myocardial infarction patients at risk of malignant arrhythmias. The three proposed TFM criteria dramatically increased the number of measurable BRSs compared to the traditional coherence-based method and provided substantially equivalent BRS measurements. The agreement between these new indexes and BRS obtained by the phenylephrine test was similar to that of the traditional coherence method.