Vagal heart rate responses to chronic beta-blockade in human heart failure relate to cardiac norepinephrine spillover
| Autor: | Gary E. Newton, John D. Parker, Peter Picton, John S. Floras, Deborah J. Atchison, Eduardo R. Azevedo, Toshihiko Kubo |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
medicine.medical_specialty
Adrenergic beta-Antagonists Carbazoles Baroreflex Propanolamines Norepinephrine Heart Rate Vagal escape Internal medicine Heart rate medicine Humans Heart rate variability Sinus rhythm Carvedilol Heart Failure Ejection fraction business.industry Vagus Nerve Middle Aged medicine.disease Heart failure Cardiology Cardiology and Cardiovascular Medicine business Metoprolol medicine.drug |
| Zdroj: | European Journal of Heart Failure. 7:878-881 |
| ISSN: | 1388-9842 |
| DOI: | 10.1016/j.ejheart.2004.10.012 |
| Popis: | We have documented a pre-junctional beta-2 adrenoceptor mediated reduction in cardiac norepinephrine spillover (CNES) in heart failure patients receiving chronic beta-blockade. Our present objective was to ascertain the consequence of this decrease for vagal heart rate (HR) regulation by determining CNES, arterial baroreflex sensitivity for HR (BRS) and arterial baroreflex modulation of muscle sympathetic nerve activity (MSNA) before and upon 4 months of beta-blockade with either carvedilol or metoprolol. In 19 heart failure patients in sinus rhythm (age: 55+/-2 [mean+/-S.E.]; ejection fraction: 20+/-2%), beta-blockade increased BRS from 4.8+/-0.9 to 7.9+/-1.3 ms/mm Hg (P0.005) but had no effect on arterial baroreflex modulation of MSNA. Changes in CNES and BRS were inversely related (r=-0.52; n=16, P0.05). Chronic beta-blockade in heart failure augments reflex vagal control of HR at an efferent site of interaction involving blockade of cardiac sympathetic pre-junctional beta-2 adrenoceptors that facilitate NE release. |
| Databáze: | OpenAIRE |
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