Left atrial distension and antiorthostatic decrease in arterial pressure and heart rate in humans
| Autor: | Peter Norsk, Bettina Pump, Jørgen Warberg, Regitze Videbæk, Niels Juel Christensen, Ole Hendriksen |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Adult
Male Baroreceptor Physiology Posture Hemodynamics Blood Pressure Distension Baroreflex Norepinephrine (medication) Hypotension Orthostatic Left atrial Heart Rate Physiology (medical) Heart rate Supine Position Medicine Humans Heart Atria business.industry Blood pressure Anesthesia Aortic Valve Atrial Function Left Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | The American journal of physiology. 273(6) |
| ISSN: | 0002-9513 |
| Popis: | It was investigated to what degree left atrial distension augments the hypotensive effects of a 15-min moderate antiorthostatic maneuver in humans. Ten healthy males underwent a posture change from upright seated (Seat, legs horizontal) to supine (Sup) or to supine with simultaneous lower body negative pressure (Sup + LBNP) to keep left atrial diameter (LAD) unchanged. After 2.5 min of Sup, mean arterial pressure (MAP) decreased from 94 ± 3 to 86 ± 3 mmHg ( P < 0.05), whereas a similar decrease was delayed 7.5 min into Sup + LBNP. Heart rate (HR) decreased within 2.5 min of Sup from 68 ± 2 to 60 ± 3 beats/min ( P < 0.05) and remained significantly decreased for at least 2.5 min longer than during Sup + LBNP. Aortic systolic distension (ASD) increased by 59 ± 17% during Sup ( P < 0.05) but was unchanged during Sup + LBNP. The 29 ± 4% decrease in plasma norepinephrine (NE) during Sup ( P < 0.05) was abolished during Sup + LBNP. In conclusion, the increases in LAD and ASD seem important stimuli for the prompt decrease in MAP, the 2.5-min longer-lasting decrease in HR, and the sustained decrease in NE during a 15-min moderate antiorthostatic posture change in humans. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|