APPLIED PHYSIOLOGY | The Heart and Anesthesia Flashcards
__ is the parasympathetic-mediated reflex occurs when stretch receptors located mainly in the left ventricle respond to an acute decrease in left ventricular preload
A. Bezold-Jarisch reflex
B. Baroreceptor reflex
C. Bainbridge reflex
D. Carotid sinus reflex
A. Bezold-Jarisch reflex
parasympathetic-mediated reflex occurs when stretch receptors located mainly in the left ventricle respond to an acute decrease in left ventricular preload. The result is bradycardia and reduced contractility (and resultant hypotension)
- this is thought to occur to give ventricle MORE TIME to fill an increase preload.
What primary mechanism is responsible for the decrease of blood pressure when volatile anesthetic is used?
A. relax the vascular smooth muscle leading to decreases in regional and systemic vascular resistance
B. constrict the vascular smooth muscle leading to decreases in regional and systemic vascular resistance
C. depresses the catecholamine secretion resulting to decreased cardiac output and vascular resistance
A. relax the vascular smooth muscle leading to decreases in regional and systemic vascular resistance
An increase in which of the following parameters will
cause a decrease in cardiac output?
(A) heart rate
(B) contractility
(C) afterload
(D) preload
(E) stroke volume
AFTERLOAD
An increase in afterload will cause a decrease in cardiac
output.
Cardiac output = stroke volume × heart rate
Stroke volume is directly proportional to preload
and contractility and INVERSELY proportional to afterload.
Therefore, increases in heart rate, preload, and
contractility will increase cardiac output, while a
decrease in afterload will increase cardiac output.
Which phase of the cardiac cycle is associated with the
greatest proportion of myocardial oxygen consumption?
(A) rapid ventricular ejection
(B) atrial systole
(C) isovolumetric contraction
(D) rapid ventricular filling
(E) isovolumetric relaxation
(C) isovolumetric contraction
Tissue edema due to heart failure is a result of:
(A) decreased Starling forces
(B) increased capillary hydrostatic pressure
(C) increased capillary oncotic pressure
(D) increased interstitial oncotic pressure
(E) increased interstitial hydrostatic pressure
(B) increased capillary hydrostatic pressure
The Starling equation describes how hydrostatic and
oncotic pressures (the Starling forces) determine the
movement of fluid between the intravascular space and
the interstitial space. Tissue edema due to heart failure
is a result of increased capillary hydrostatic pressure,
which causes movement of fluid from the intravascular
space to the interstitial space.
Tissue edema may also occur when there is decreased capillary oncotic pressure (e.g., nephrotic syndrome).
Blood supply to the LV is inversely related to the vascular resistance to flow, which varies to the fourth power of the radius of the vessel:
A. Laplace’s Law
B. Bernoulli’s principle
C. Frank-Starling effect
D. Poiseuille’s Law
D. Poiseuille’s Law
The “dominance” of the coronary circulation is determined on the basis of which major coronary artery feeds the
_______
A. Left anterior descending coronary artery
B. Left circumflex artery
C. Posterior descending coronary artery
D. Right coronary artery
C. Posterior descending coronary artery
What is the primary determinant of myocardial O2 demand?
A. Heart rate
B. Contractility
C. Afterload
D. Preload
A. Heart rate
This is the amount of blood that a chamber contains immediately before contraction BEGINS:
A. PRELOAD
B. AFTERLOAD
C. MYOCARDIAL RESISTANCE
A. PRELOAD
In 55% of patients, the sinoatrial (SA) node
is perfused by the ________
A. Left anterior descending coronary artery
B. Left circumflex artery
C. Posterior descending coronary artery
D. Right coronary artery
D. Right coronary artery
Blood supply to the LV is inversely related to the vascular resistance to flow, which varies to the fourth power of the radius of the vessel:
A. Laplace’s Law
B. Bernoulli’s principle
C. Frank-Starling effect
D. Poiseuille’s Law
D. Poiseuille’s Law
What is the primary determinant of myocardial O2 demand?
A. Heart rate
B. Contractility
C. Afterload
D. Preload
A. Heart rate
Which of the following is most accurate in terms of the hemodynamic goal in Coronary artery disease(CAD)
A. Decrease in preload
B. Maintain tachycardia
C. Increase in preload
D. Increase in afterload
A. Decrease in preload
In the current guideline of ACLS, when a patient is suspected to have a β-blocker or calcium channel blocker overdose, the epinephrine dose can be increased to:
A. 3 - 7 mg
B. 2 - 3 mg
C. 3 - 4 mg
A. 3 - 7 mg
Current recommendations are to give 1 mg of epinephrine IV every 3 to 5 minutes in the adult. The easiest way to manage this is to administer 1 mg of epinephrine approximately every other 2-minute cycle of CPR (i.e., about
every 4 minutes).
If this dose seems ineffective or in the setting of β-blocker
or calcium channel blocker overdose, higher doses (3 to 7 mg) may be considered.
The innervation of AV node is primarily from:
A. Right vagus nerve
B. Left vagus nerve
C. Cardio-accelerator fibers (T1-T4)
B. Left vagus nerve
Dictum:
SA node: Right vagus
AV node: Left vagus
Is the external resistance to chamber emptying after contraction begins and the aortic valve opens:
A. PRELOAD
B. AFTERLOAD
C. MYOCARDIAL RESISTANCE
B. AFTERLOAD
This is the amount of blood that a chamber contains immediately before contraction BEGINS:
A. PRELOAD
B. AFTERLOAD
C. MYOCARDIAL RESISTANCE
A. PRELOAD
Is the force of contraction under controlled heart rate and loading conditions:
A. PRELOAD
B. AFTERLOAD
C. MYOCARDIAL CONTRACTILITY
Myocardial contractility
This refers to the mechanism whereby alterations in muscle tension and length that occur during contraction and relaxation in the sarcomere are translated into phasic changes in pressure and volume that occur in the intact heart:
A. Laplace Law
B. Poiseuille’s Law
C. Frank-Starling Mechanism
A. Laplace Law
Analogously, the elevated LV pressure in severe aortic valve stenosis produces greater systolic LV wall stress. These increases in LV wall stress cause parallel increases in
myocardial oxygen demand because the myofilaments require more energy to develop enhanced tension.
Conversely, Laplace’s law indicates that an increase in wall thickness will reduce wall stress and tension developed by individual sarcomeres.
Major phases of left ventricular systole EXCEPT:
A. Isovolumic contraction
B. Atrial systole
C. Rapid ejection
D. Slower ejection
B. Atrial systole
The first phase of LV systole is isovolumic contraction, which describes the time interval between mitral valve closure
and aortic valve opening during which LV volume remains constant.
Major phases of LV diastole EXCEPT:
A. isovolumic relaxation
B. early ventricular filling
C. slower ejection
D. atrial systole
C. slower ejection
LV diastole is divided into four phases: isovolumic relaxation, early ventricular filling, diastasis, and atrial systole.
“c” wave of the left atrium pressure
waveform represents _______
A. Left atrial contraction
B. Left atrial filling during left ventricular early relaxation
C. Mitral valve closure during left ventricular systole
D. Diastasis
C. Mitral valve closure during left ventricular systole
“x descent of the left atrium pressure waveform corresponds to which cardiac mechanical event:
A. Atrial contraction
B. Atrial relaxation
C. Early ventricular filling
B. Atrial relaxation
Formula for ejection fraction:
A. Stroke volume / end-diastolic volume
B. Stroke volume / end-systolic volume
C. End-systolic volume / end-diastolic volume
D. End-systolic volume / stroke volume
A. Stroke volume / end-diastolic volume