© 2008 European Society of Cardiology
Sympathetic activation in congestive heart failure: Reproducibility of neuroadrenergic markers
a Clinica Medica, Dipartimento di Medicina Clinica, Prevenzione e Biotecnologie Sanitarie, Università Milano-Bicocca Ospedale San Gerardo, Monza (Milan), Italy
b Centro di Fisiologica Clinica e Ipertensione Milan, Italy
c Istituto Auxologico Italiano Milan, Italy
* Corresponding author. Clinica Medica, Ospedale S Gerardo, Via Pergolesi 33, 20052 Monza (Milano), Italy. Tel.: +39 039 2333357; fax: +39 039 322274. E-mail address: guido.grassi{at}unimib.it (G. Grassi).
| Abstract |
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Objective: To assess the reproducibility of the two markers of adrenergic drive, venous plasma norepinephrine (NE) and efferent postganglionic muscle sympathetic nerve activity (MSNA), in reflecting the sympathetic activation characterizing congestive heart failure (CHF).
Methods and measurements: In 19 CHF male normotensive patients (mean age: 53.0±2.1 years, NYHA classes II and III, left ventricular ejection fraction 35.9±2.9%), blood pressure (BP, Finapres), heart rate (EKG), plasma NE (HPLC assay) and MSNA (microneurography, peroneal nerve) were measured in two experimental sessions separated by a week interval. At each session, three NE samples were obtained and NE reproducibility between sessions was assessed by considering single NE samples or averaging 2–3 samples.
Results: While MSNA values showed a highly significant correlation between sessions (r = 0.85, P<0.001), NE values based on a single blood sample evaluation did not correlate with each other (r = 0.41, P = NS). NE correlation coefficients improved and achieved statistical significance when average data from 2 and 3 blood samples were examined (r = 0.54 and r = 0.57, P<0.02 for both).
Conclusions: In CHF, MSNA displays a better reproducibility pattern than plasma NE. The reproducibility of the NE approach, however, can be improved by performing the assay on multiple blood samples.
Key Words: Heart failure Sympathetic activity Plasma norepinephrine Muscle sympathetic nerve traffic Muscle sympathetic nerve activity
Received April 28, 2008; Revised July 30, 2008; Accepted September 24, 2008