Cardiac quizzlet Flashcards
During which interval on the EKG does the aortic valve close?
T-wave
Which one of the following is the best index of preload?
Left ventricular end-diastolic volume
Which one of the following is the best index of afterload?
Left ventricular mean systolic pressure
The highest blood flow per gram of left ventricular myocardium would occur
At the beginning of diastole
During ventricular ejection, the pressure difference smallest in magnitude is between the
Left ventricle and aorta
Which of the following would result from a regurgitant aortic valve in a nonfailing heart?
A decrease in diastolic pressure
Stroke volume is increased by
A decrease in venous compliance
An increased preload would most likely be caused by an increase in
Venous tone
Propagation of the action potential through the heart is fastest in the
Purkinje fibers
A patient in heart failure improves markedly after using a drug that increases the inotropic state of her heart. Which one of the following changes is primarily responsible for the improvement in her condition?
A reduction in heart size
Closure of the aortic valve occurs at the onset of which phase of the cardiac cycle?
Isovolumetric relaxation
Which one of the following is most likely to be observed in a patient with untreated atrial fibrillation?
An increased left atrial pressure
Normal splitting of the second heart sound (S2) into two components is increased during inspiration because
The closing of the pulmonic valve is delayed
Which of the following statements about the third heart sound (S3) is correct?
It is produced by turbulence during rapid ventricular filling in early diastole
In a resting, healthy man, the ejection fraction is approximately?
0.6
Sustained elevation of cardiac output will occur with which of the following conditions?
Anemia
A diastolic murmur accompanied by an increased preload can be caused by
Aortic regurgitation
Increasing vagal stimulation of the heart will cause an increase in
PR interval
During exercise, there is an increase in a person’s
Stroke volume
Phase-4 depolarization of SA nodal cells is caused by
An increase in the flow of sodium into the cell
Cardiovascular changes that occur during inspiration include decreased
Systemic blood pressure
Blood pressure increases and heart rate decreases in response to
Increased intracranial pressure
During exercise, cardiac output is augmented by
Increased ventricular contractility
When flow through the mitral valve is restricted by mitral stenosis,
Exercise can induce acute pulmonary edema
Stroke volume can be decreased by
Increasing heart rate
An ectopic extrasystole caused by a ventricular focus is characterized by
A skipped ventricular contraction
The electrocardiogram is most effective in detecting a decrease in
Coronary blood flow
Stroke volume can be increased by
Decreasing total peripheral resistance
Which one of the following will be observed in a patient with a dilated failing left ventricle and a normal resting mean blood pressure?
An increased pulmonary capillary hydrostatic pressure
Which one of the following correctly describes an event that normally occurs during the PR interval?
The cardiac action potential passes through the AV node
Left ventricular wall stress will be decreased by an increase in
The thickness of the free wall of the left ventricle
Which one of the following will be observed in a patient with aortic regurgitation?
An increased ejection fraction
At which point on the above ventricular action potential is membrane potential most dependent on calcium permeability?
Point D
During which interval on the ECG does the bundle of His depolarize?
PR
The diagnosis of a first-degree heart block is made if
The PR interval of the ECG is increased
Positive inotropic drugs such a digitalis reduce ischemic cardiac pain (angina) in a dilated failing heart by
Decreasing preload
The mitral valve opens at point
A
The second heart sound begins at point
B
Systole begins at point
E
A major sign of cardiac tamponade is
Pulsus paradoxus
A mild hemorrhage will cause stroke volume to shift from point X to point
A
An increase in afterload and venous compliance can cause stroke volume to change from the point marked X to point
C