In what areas are the murmurs of aortic stenosis and aortic regurgitation best heard?
(A) aortic area (i.e., right sternal border and second intercostal space) and (E) left sternal border, respectively
In what areas are the murmurs of pulmonic stenosis and pulmonic regurgitation best heard?
(B) pulmonic area (i.e., left sternal border at second intercostal space) and (E) left sternal border, respectively
On which part of the chest are tricuspid valve murmurs best auscultated?
(C) tricuspid area (i.e., the left sternal border at the fifth intercostal space)
In what area is the murmur of a ventricular septal defect best heard?
(C) tricuspid area (i.e., left sternal border at fifth intercostal space)
In what area is the murmur of an atrial septal defect best heard?
(C) tricuspid area
In what areas are flow murmurs best heard?
(A) aortic area and (B) pulmonic area
In what area is the murmur of hypertrophic cardiomyopathy best heard?
(E) left sternal border
What are the two equations for mean arterial pressure?
Mean atrial pressure = cardiac output x total peripheral resistance; mean atrial pressure = (1/3) systolic pressure + (2/3) diastolic pressure
Pulse pressure is proportional to what other cardiac parameter?
What accounts for the increase in cardiac output in the first stages of exercise?
An increase in stroke volume is responsible for the increase in cardiac output in the first stages of exercise
What accounts for the increase in cardiac output after prolonged exercise?
An increase in heart rate is responsible for the increase in cardiac output after prolonged exercise
What accounts for the decrease in cardiac output at very high heart rates?
At very high heart rates, the ventricles are unable to fill completely during diastole; therefore, the cardiac output decreases
Cardiac output = stroke volume x _____ _____.
What is Ficks principle?
Cardiac output = rate of oxygen consumption / (arterial oxygen content - venous oxygen content)
Stroke volume = end-diastolic volume - _____ _____.
With an increase in stroke volume, one would expect the heart to have a(n) _____ (decrease/increase) in preload, a(n) _____ (decrease/increase) in afterload, and/or a(n) _____ (decrease/increase) in contractility.
Increase; decrease; increase
What are the three variables that affect stroke volume?
Contractility, Afterload, and Preload (remember the mnemonic SV CAP)
How does digitalis affect contractility (and thus stroke volume)?
Digitalis increases contractility by causing an increase in intracellular sodium, which results in an increase in intracellular calcium, which strengthens contractions
How does hypoxia affect contractility?
Hypoxia causes a decrease in contractility and in stroke volume
How do calcium channel blockers affect contractility and stroke volume?
Calcium channel blockers decrease contractility and stroke volume by decreasing intracellular calcium
How does increasing intracellular calcium affect contractility (and thus stroke volume)?
An increase in intracellular calcium increases contractility; this is the mechanism of digitalis
How does decreasing extracellular sodium affect contractility (and thus stroke volume)?
A decrease in extracellular sodium increases contractility by decreasing the activity of the sodium/calcium ion exchanger
How does acidosis affect contractility?
Acidosis decreases contractility
Would a patient with hypertrophic cardiomyopathy have an increase or decrease in myocardial oxygen demand?
How does 1 blockade affect contractility and stroke volume?
1 blockade decreases contractility and stroke volume
Would chronic hypertension increase or decrease myocardial oxygen demand? By what mechanism?
Chronic hypertension would cause an increase in myocardial oxygen demand by causing an increase in afterload
How do catecholamines affect contractility (and thus stroke volume)?
Catecholamines increase contractility
By what mechanism do catecholamines cause an increase in contractility?
By increasing the activity of the calcium pump in the sarcoplasmic reticulum
Does pregnancy increase or decrease stroke volume?
By what mechanism does increasing heart size increase myocardial oxygen demand?
By causing an increase in wall tension