Attenuation of baroreflex changes in cardiac sympathetic efferent activities during acute myocardial ischemia
| Autor: | Gilbert R. Hageman, Nicholas S. Gantenberg |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Male
Mean arterial pressure Sympathetic Nervous System Time Factors Efferent Ischemia Myocardial Ischemia Blood Pressure Pressoreceptors Baroreflex Efferent Pathways Sudden cardiac death Nitroglycerin Phenylephrine Dogs Reflex medicine Animals business.industry Heart medicine.disease Blood pressure Anesthesia Female Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | American heart journal. 126(2) |
| ISSN: | 0002-8703 |
| Popis: | Sympathetic efferent activities to the heart during blood pressure changes were investigated in 11 dogs with acute myocardial ischemia. Normalized sympathetic efferent activities recorded in thoracic cardiac nerves decreased or increased as anticipated in response to transient changes in mean arterial pressure (15 to 25 mm Hg with nitroglycerin or phenylephrine, 2 to 8 micrograms/kg, intravenously). A branch of the left circumflex coronary artery was occluded, and the arterial pressure challenges were repeated at 5, 15, and 25 minutes after the occlusion. The control (preocclusion) responses in sympathetic efferent activities to the heart ranged from +/- 2% to 70% (changes relative to steady state normalized at 100%). Reflex sympathetic efferent responses were diminished at 15 and 25 minutes of ischemia. Several sympathetic efferent baroreflex responses during myocardial ischemia were paradoxic. Reflex sympathetic efferent changes were not affected in sham animals. These results indicate that both increases and decreases in cardiac sympathetic efferent activities during baroreflex challenges are attenuated within 15 to 25 minutes of acute coronary artery occlusion. These findings suggest that an abnormal buffering of blood pressure changes during acute myocardial ischemia might lead to autonomic dysfunction that promotes arrhythmogenesis and sudden cardiac death. |
| Databáze: | OpenAIRE |
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