Abstract
Cardiac ischemia and angina pectoris are commonly experienced during exertion in a cold environment. In the current study we tested the hypotheses that oropharyngeal afferent blockade (i.e., local anesthesia of the upper airway with lidocaine) as well as systemic β-adrenergic receptor blockade (i.e., intravenous propranolol) would improve the balance between myocardial oxygen supply and demand in response to the combined stimulus of cold air inhalation (-15 to -30°C) and isometric handgrip exercise (Cold + Grip). Young healthy subjects underwent Cold + Grip following lidocaine, propranolol, and control (no drug). Heart rate, blood pressure, and coronary blood flow velocity (CBV, from Doppler echocardiography) were continuously measured. Rate-pressure product (RPP) was calculated, and changes from baseline were compared between treatments. The change in RPP at the end of Cold + Grip was not different between lidocaine (2,441± 376) and control conditions (3,159± 626); CBV responses were also not different between treatments. With propranolol, heart rate (8± 1 vs. 14± 3 beats/min) and RPP responses to Cold + Grip were significantly attenuated. However, at peak exercise propranolol also resulted in a smaller CBV (1.4± 0.8 vs. 5.3± 1.4 cm/s, P < 0.035), such that the relationship between coronary flow and cardiac metabolism was impaired under propranolol (0.43± 0.37 vs. 2.1± 0.63 arbitrary units). These data suggest that cold air breathing and isometric exercise significantly influence efferent control of coronary blood flow. Additionally, β-adrenergic vasodilation may play a significant role in coronary regulation during exercise.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 307 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jul 15 2014 |
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All Science Journal Classification (ASJC) codes
- Physiology
- Physiology (medical)
- Cardiology and Cardiovascular Medicine
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Coronary responses to cold air inhalation following afferent and efferent blockade. / Muller, Matthew; Gao, Zhaohui; McQuillan, Patrick; Leuenberger, Urs; Sinoway, Lawrence.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 307, No. 2, 15.07.2014.Research output: Contribution to journal › Article
TY - JOUR
T1 - Coronary responses to cold air inhalation following afferent and efferent blockade
AU - Muller, Matthew
AU - Gao, Zhaohui
AU - McQuillan, Patrick
AU - Leuenberger, Urs
AU - Sinoway, Lawrence
PY - 2014/7/15
Y1 - 2014/7/15
N2 - Cardiac ischemia and angina pectoris are commonly experienced during exertion in a cold environment. In the current study we tested the hypotheses that oropharyngeal afferent blockade (i.e., local anesthesia of the upper airway with lidocaine) as well as systemic β-adrenergic receptor blockade (i.e., intravenous propranolol) would improve the balance between myocardial oxygen supply and demand in response to the combined stimulus of cold air inhalation (-15 to -30°C) and isometric handgrip exercise (Cold + Grip). Young healthy subjects underwent Cold + Grip following lidocaine, propranolol, and control (no drug). Heart rate, blood pressure, and coronary blood flow velocity (CBV, from Doppler echocardiography) were continuously measured. Rate-pressure product (RPP) was calculated, and changes from baseline were compared between treatments. The change in RPP at the end of Cold + Grip was not different between lidocaine (2,441± 376) and control conditions (3,159± 626); CBV responses were also not different between treatments. With propranolol, heart rate (8± 1 vs. 14± 3 beats/min) and RPP responses to Cold + Grip were significantly attenuated. However, at peak exercise propranolol also resulted in a smaller CBV (1.4± 0.8 vs. 5.3± 1.4 cm/s, P < 0.035), such that the relationship between coronary flow and cardiac metabolism was impaired under propranolol (0.43± 0.37 vs. 2.1± 0.63 arbitrary units). These data suggest that cold air breathing and isometric exercise significantly influence efferent control of coronary blood flow. Additionally, β-adrenergic vasodilation may play a significant role in coronary regulation during exercise.
AB - Cardiac ischemia and angina pectoris are commonly experienced during exertion in a cold environment. In the current study we tested the hypotheses that oropharyngeal afferent blockade (i.e., local anesthesia of the upper airway with lidocaine) as well as systemic β-adrenergic receptor blockade (i.e., intravenous propranolol) would improve the balance between myocardial oxygen supply and demand in response to the combined stimulus of cold air inhalation (-15 to -30°C) and isometric handgrip exercise (Cold + Grip). Young healthy subjects underwent Cold + Grip following lidocaine, propranolol, and control (no drug). Heart rate, blood pressure, and coronary blood flow velocity (CBV, from Doppler echocardiography) were continuously measured. Rate-pressure product (RPP) was calculated, and changes from baseline were compared between treatments. The change in RPP at the end of Cold + Grip was not different between lidocaine (2,441± 376) and control conditions (3,159± 626); CBV responses were also not different between treatments. With propranolol, heart rate (8± 1 vs. 14± 3 beats/min) and RPP responses to Cold + Grip were significantly attenuated. However, at peak exercise propranolol also resulted in a smaller CBV (1.4± 0.8 vs. 5.3± 1.4 cm/s, P < 0.035), such that the relationship between coronary flow and cardiac metabolism was impaired under propranolol (0.43± 0.37 vs. 2.1± 0.63 arbitrary units). These data suggest that cold air breathing and isometric exercise significantly influence efferent control of coronary blood flow. Additionally, β-adrenergic vasodilation may play a significant role in coronary regulation during exercise.
UR - http://www.scopus.com/inward/record.url?scp=84904291646&partnerID=8YFLogxK
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U2 - 10.1152/ajpheart.00174.2014
DO - 10.1152/ajpheart.00174.2014
M3 - Article
C2 - 24816257
AN - SCOPUS:84904291646
VL - 307
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6135
IS - 2
ER -