SYNCOPE Flashcards
triggered by centrally mediated inhibition of the normal tonic sympathetic
influences, is often associated with excessive vagal
effect and bradycardia (vagal effect)
vasovagal syncope
is meant the withdrawal of sympathetic tone through a
reflex neural mechanism
neurocardiogenic syncope
Neurocardiogenic syncope usually
signifies that the inciting stimulus originates in ________
neural
receptors within the heart
failure of sympathetic innervation of blood vessels and of autonomically activated compensatory responses (reflex tachycardia and vasoconstriction), which occurs with assumption of the upright body position
and leads to pooling of blood in the lower parts of
the body
orthostatic hypotension
caused by a primary diminished
cardiac output because of disease of the heart itself
as in the ____________ bradyarrhythmia attack, severe
aortic or subaortic stenosis, or ischemic heart disease
Stokes-Adams
The vasodepressor faint occurs
(1) in normal health under the influence of strong emotion, particularly in some susceptible individuals (sight of blood or an accident) or in conditions that ___________
e. g., hot, crowded rooms (“heat syncope”), e
favor peripheral vasodilatation,
The vasodepressor faint occurs
2) during a ____________ (especially
of the abdomen or genitalia), as a consequence of
fright, pain, and other factors (where pain is involved, the
vagal element tends to be more prominent in the genesis
of the faint
(3) during ______ in some sensitive persons
painful illness or after bodily injury
exercise
authentic seizure caused by a prolonged period of
brain hypoxia
con vulsive syncope
heightened vagal discharge produced by compression
of the eyeballs _________could produce brief periods of cardiac
arrest and syncope
( oculovagal reflex, a cause of syncope in
acute glaucoma)
T or F
In essence, all the types of
syncope in this category are “vasovagal,” meaning a combination
of vasodepressor and vagal effects in varying
proportions; the only differences are in the stimuli that
elicit the reflex response.
T
Unmyelinated (postganglio sympathec)
fibers cease firing during vasovagal famting at a pomt
when the blood pressure falls below _______ mm Hg
and the pulse, below ________
80/40
60
There is agreement that peripheral vascular resiStance
is greatly reduced just prior to and at th onset of
fainting. This drop in resistance has been attributed to
an initial _______discharge that, at high levels, causes
a ___________
adrenergic
vasodilatation
the drpp in blood
pressure is the result of a transient ut excessive activity
of sympathetic nerves that paradoXIcally leads to vascular dilatation in muscle and viscera from an _______
imbalance between beta-adrenergic and alpha-adrenergic activity
peripherally.
Oberg and Thoren were the first to observe tha the
_______ itself can be the source of neurally mediated
syncope in much the same way as the _______when
stimulated, produces vasodilatation and bradycardi.
left ventricle
carotid sinus
the heart as the afferent
source of vasodepressor reflexes
Bezold-Jansch reflex.
The _______ is the site of most ofthe
subendocardial mechanoreceptors that are responsible
for the afferent impulses to the nucleus tractus solitarius
inferoposterior
wall of the left ventricle
a proclivity to primary neurocardiogenic
syncope can be identified by the finding of
delayed fainting when the patient is placed at __________ position on a tilt table.
After approXImately _________ the blood pressure drps belw100 mm Hg; soon thereafter, the patient complams of diZziness and sweating and subsequently faints.
In contrast,
patients with primary sympathetic failure will faint________
60-degree upright
10 min of upright posture,
s oon
after upward tilting.
Th e ____________ i s normally sensitive t o stretch and gives rise to sensory impulses carried via the nerve of Hering, a tributary of the glossopharyngeal nerve, to the medulla.
carotid sinus
Massage of one of the carotid sinuses or of both alternately, particularly in elderly persons, causes
(1) a reflex cardiac
slowing (sinus bradycardia, sinus arrest, or even atrioventricular
block)-the ________, or
(2) a fall of
arterial pressure without cardiac slowing-the __________
vagal type of response
vasodepressor type of response.
Pathophysio of syncope in Glossopharyngeal neuralgia
Presumably the pain gives rise to a massive volley of afferent impulses
along the ninth cranial nerve, activating the medullary
vasomotor centers via collateral fibers from the nucleus
of the tractus solitarius. An increase in parasympathetic
(vagal) activity slows the heart
consciousness is
lost during or immediately after a forceful swallow.
The
administration of anticholinergic drugs ___________ has abolished these attacks
deglutitional syncope
propantheline 15 mg tid
Pathophysio of micturition syncope
A full bladder causes reflex ______ as the bladder empties, this gives way to ______ which, combined with
an element of postural hypotension, might be sufficient to
cause fainting in some individuals
vasoconstriction;
vasodilatation,
Pathophysio of tussive syncope
This is mainly attributable to the greatly elevated
intrathoracic pressure, which interferes with venous
return to the heart.
______and ________, with resultant cerebral vaso constriction, are possibly contributing factors
Increased cerebrospinal fluid (CSF) pressure
diminished Pco2
the so-called ________ in infants probably represent
reflex vasodepression
pallid attacks
