Comparison of methods to measure baroreflex sensitivity in Brugada syndrome

Baroreflex sensitivity (BRS) is a valuable index to assess cardiovascular autonomic control and therefore to provide prognostic evaluation in many cardiac diseases. Although several methods have been developed to noninvasively capture spontaneous BRS, they are difficult to compare and often provide conflicting results. In this study we analyzed different BRS estimates obtained from a clinical series of thirty-two patients diagnosed with Brugada syndrome. They took part in a standardized head-up tilt test in order to quantify the level of agreement between the following measures: (1) BRS+/+ and (2) BRS-/- from sequence analysis, (3) BRS-LF, (4) BRS-HF, (5) BRS-LHF, (6) BRS-TF and (7) BRS-TFLF from cross-spectral analysis and (8) BRS-SD. Measures resulting from the sequence method failed to provide results in many recordings and showed low agreement with the remaining methods based on intraclass correlation coefficient results. Assuming an age-associated reduction in BRS, which has been previously reported, the lowest Pearson´s correlation coefficients came from sequence analysis results. Thus, among the analyzed BRS estimates, those derived from sequence analysis showed a lower reliability when capturing baroreflex function in Brugada syndrome patients.