利用平躺抬高腿部試驗發現腿部抬高時舒張壓降低,但抽一根菸後收縮壓,舒張壓,及心跳立刻昇高; 腿部抬高時肱骨動脈之管徑增大(副交感啟動),但抽一根菸後管徑縮小; 腿部抬高時LF/HF降低, 但抽一根菸後立刻昇高
Effects of smoking on cardiopulmonary baroreceptor activation and peripheral vascular resistance.
Eur J Clin Invest. 2006; 36(5):320-5 (ISSN: 0014-2972)
Arosio E; De Marchi S; Rigoni A; Prior M; Lechi A
Division of Cardiovascular Rehabilitation, University of Verona, Valeggio Hospital, Verona, Italy. email@example.com
PATIENTS AND METHODS: We studied 16 healthy smokers and 16 nonsmokers acting as controls. We subjected smokers and nonsmokers to cardiopulmonary baroreceptor stimulation by studying forearm and common carotid haemodynamic and sympathovagal balance. Smokers repeated the tests after smoking one cigarette. Smokers and controls were subjected to passive elevation of the legs and the trunk in a horizontal position with pressure monitoring and measurement of the calibre and flow in the brachial and common carotid arteries using a colourDoppler ultrasound. We calculated forearm resistance and carotid wall tension. We also studied R-R variability, calculating the ratio between low frequency (LF) and high frequency (HF) R-R interval variability. RESULTS: During stimulation diastolic blood pressure values decreased in controls and in smokers at rest. After smoking one cigarette, smokers showed an increase in systolic and diastolic blood pressure as well as in the heart rate during stimulation. Humeral artery increased the calibre during stimulation in both groups; after cigarette smoking the calibre declined throughout the study phases. Forearm resistance decreased in both groups during stimulation at rest, but increased after cigarette smoking. The LF/HF ratio decreased during stimulation in both groups, and it increased at rest after smoking. Carotid diameter did not change in either group, and wall tension increased in smokers after smoking one cigarette. CONCLUSIONS: Smoking one cigarette increases resistance, impairs baroreflex and increases carotid wall tension in mild smokers. These findings may explain the higher rate of a cardiovascular event in smokers.