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Spontaneous baroreflex control of muscle sympathetic nerve activity: Impact of baseline duration
Author(s) -
Holwerda Seth W.,
Vianna Lauro C.,
Fadel Paul J.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1091.80
Subject(s) - baroreflex , intraclass correlation , medicine , blood pressure , heart rate , cardiology , anesthesia , psychometrics , clinical psychology
The relationship between spontaneously occurring changes in muscle sympathetic nerve activity (MSNA) and diastolic blood pressure (DBP) is increasingly being used to estimate baroreflex MSNA sensitivity. Although spontaneous measures have been shown to correlate with MSNA baroreflex sensitivity derived using the modified Oxford, standardized analyses procedures have not been established. For example, studies have used varying durations of baseline for this analysis and whether spontaneous baroreflex measures are affected by the period of data used (e.g., 5 vs. 2min) is unknown. Also, how bin size impacts the reliability of different durations is unknown. To begin to address this, in 8 subjects, weighted linear regression analysis between MSNA and DBP was used to determine baroreflex MSNA sensitivity. Intraclass correlation coefficients (ICC) for each bin size (1, 2, and 3 mmHg) were calculated to examine reliability of spontaneous MSNA sensitivity over segment durations of 2‐, 5‐, and 10‐minutes. Overall ICC for burst incidence was high (0.884; P<0.05) indicating an acceptable reliability. Importantly, the reliability over different segment durations was unaffected by bin size (e.g., 3 mmHg bins: ICC=0.875, P<0.05). Similar results were found for burst strength. These preliminary findings suggest that the duration of baseline and bin size does not affect spontaneous MSNA baroreflex estimates at rest.