Download Near-Syncope After Exercise

From: Near-Syncope After Exercise
JAMA. 2004;292(10):1221-1226. doi:10.1001/jama.292.10.1221
Figure Legend:
The carotid sinus is a small dilatation of the internal carotid arteryimmediately above the bifurcation of the common carotid artery
that containsspecialized sensory nerve endings sensitive to pressure or stretch. To performcarotid sinus massage, firm but gentle
pressure is applied to the area atthe midpoint between the angle of the mandible and the superior border ofthe thyroid cartilage
along the anterior margin of the sternocleidomastoidmuscle.
Date of download: 5/2/2017
Copyright © 2004 American Medical
Association. All rights reserved.
From: Near-Syncope After Exercise
JAMA. 2004;292(10):1221-1226. doi:10.1001/jama.292.10.1221
Figure Legend:
A, A pure cardioinhibitory response produces a reflex slowing ofthe heart and may produce sinus arrest or asystole. A fall in systolic
bloodpressure typically occurs deriving from and proportional to the extent andduration of the decrease in heart rate. During carotid
sinus massage, a positivecardioinhibitory response is defined as a ventricular pause of more than 3seconds. If the slowing of the
heart is prevented (for example with a pacemaker),individuals exhibiting a pure cardioinhibitory response will not experiencea
decline in blood pressure. B, A pure vasodepressor
response
produces
hypotensionwithout
bradycardia due chiefly to inhibition of
Copyright
© 2004
American
Medical
Date
of download:
5/2/2017
sympathetic
vasoconstriction.A
pure vasodepressor
response
results
in
a
decline
in
systolic
blood pressurethat is of longer duration
Association. All rights reserved.
than that observed in a pure cardioinhibitory response.During carotid sinus massage, a positive vasodepressor response is