Cardio - Physiology (Part 1) Flashcards
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 fourth intercostal space)
In what area is the murmur of an atrial septal defect best heard?
(B) pulmonic 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?
(MAP)
- MAP = cardiac output x total peripheral resistance
- MAP = (1/3) systolic pressure + (2/3) diastolic pressure
Pulse pressure is proportional to what other cardiac parameter?
Stroke volume
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 _____ _____.
Heart rate
What is Ficks principle?
Cardiac output = rate of oxygen consumption / (arterial oxygen content - venous oxygen content)
Stroke volume = end-diastolic volume - _____ _____.
End-systolic 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?
Increase
How does β1 blockade affect contractility and stroke volume?
β1 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?
Increase
By what mechanism does increasing heart size increase myocardial oxygen demand?
By causing an increase in wall tension
Does increasing contractility increase or decrease myocardial oxygen demand?
Increase
________ (Preload/Afterload) = ventricular end-diastolic volume.
Preload
_____ (Preload/Afterload) = mean arterial pressure.
Afterload
Would you expect nitroglycerin to decrease preload or afterload? By what mechanism?
Nitroglycerin decreases preload by causing venodilation
Would you expect hydralazine to decrease preload or afterload? By what mechanism?
Hydralazine decreases afterload by causing arterial dilation
A 60-year-old male patient mistakenly receives triple the maintenance level of intravenous fluids for 24 hours. Do you expect his preload to increase or decrease?
Increase
An increase in peripheral resistance will cause an _____ (increase/decrease) in afterload.
Increase
The Starling curve represents the relationship between which two cardiac parameters?
Preload and cardiac output
The Starling curve shows that the force of contraction is proportional to what?
The preload or the initial length of the cardiac muscle fiber
Do β-blockers and calcium channel blockers increase or decrease contractile strength?
Decrease
Does sympathetic stimulation increase or decrease contractility of the heart?
Increase
Do circulating catecholamines increase or decrease contractility of the heart?
Increase
Does digitalis increase or decrease contractile strength?
Increase
What is the equation for ejection fraction?
Ejection fraction = (end-diastolic volume - end-systolic volume) ÷ end-diastolic volume
The cardiac ejection fraction is normally greater than what percentage of the total end-diastolic volume?
55%
Would an increase in end-diastolic volume be indicative of an increase or decrease in the ejection fraction?
Increase
In a failing heart, it might cause a decrease in EF.
Ejection fraction is used as an indication of which cardiac parameter?
Contractility
Ejection fraction = _____ _____ / end-diastolic volume.
Stroke volume
Name three hematologic disease states in which the viscosity of blood increases.
Polycythemia, multiple myeloma (or other hyperproteinemic states), hereditary spherocytosis
What is Ohms law?
Change in voltage (V1 - V2) = current (I) x resistance (R)
In cardiology, by what factor does resistance increase in a vessel whose size is reduced by one half?
16 times; resistance is inversely proportional to the radius to the fourth power
Which equation in cardiology, relating the variables of resistance, pressure, and flow, is a restatement of Ohms law?
Change in pressure (P1 - P2) = flow (Q) x resistance (R)
Which blood vessels account for most of total peripheral resistance?
Arterioles
What is the equation for blood vessel resistance that incorporates variables of viscosity, length, and radius?
Resistance = (8 x viscosity x length) / ( x [r4])
Pressure gradient drives flow from _____ (high/low) pressure to _____ (high/low) pressure.
High; low
What is the equation for the total resistance of blood vessels in series?
Total resistance = R1 + R2 + R3…
What is the equation for the total resistance of blood vessels in parallel?
1/(Total resistance) = 1 / R1 + 1 / R2 + 1 / R3…
Which parameter does the viscosity of blood mostly depend on?
Hematocrit
An increase in blood volume leads to a(n) _____ (increase/decrease) in right atrial pressure and a(n) _____ (increase/decrease) in cardiac output.
Increase; increase
What is the name for the point at which cardiac output is equal to venous return?
The operating point of the heart
A 23-year-old man has significant blood loss following a motor vehicle accident. A decrease in blood volume leads to a(n) _____ (increase/decrease) in right atrial pressure and a(n) _____ (increase/decrease) in cardiac output.
Decrease; decrease
What does the x-intercept of the venous return curve signify?
The value of the mean systemic pressure
A 76-year-old man with congestive heart failure is given digoxin as a positive inotrope. An increase in inotropy leads to a(n) _____ (increase/decrease) in cardiac output and a(n) _____ (increase/decrease) in right atrial pressure.
Increase; increase
A 10-year-old boy presents with dehydration following acute diarrhea. He receives 2 liters of normal saline. An increase in blood volume leads to a(n) _____ (increase/decrease) in right atrial pressure and a(n) _____ (increase/decrease) in cardiac output.
Increase; increase
What causes the S4 heart sound or atrial kick?
The left atrium pushing against a stiff left ventricular wall in a patient with ventricular hypertrophy
What phase of the cardiac cycle corresponds with the period between the opening and closing of the aortic valve?
Systolic ejection
In relation to the cardiac cycle, the A wave of the jugular venous pulse is associated with what?
Contraction of the atrium
What phase of the cardiac cycle corresponds with the period between mitral valve closure and aortic valve opening?
Isovolumetric contraction
What is the name of the finding on auscultation that occurs when the aortic valve closes before the pulmonic valve?
S2 splitting
What phase of the cardiac cycle corresponds with the period just after mitral valve opening?
Rapid filling
On auscultation of a patient with an atrial septal defect during inspiration, does the time period between pulmonic and aortic valvular closure increase, decrease, or stay the same?
Stays the same; because pressures can equalize across the atrial wall, there is no change in splitting during inspiration
What phase of the cardiac cycle corresponds with the period just before mitral valve closure?
Reduced filling
What phase of the cardiac cycle corresponds with the period of highest oxygen consumption?
Isovolumetric contraction
What phase of the cardiac cycle corresponds with the period between the closing of the aortic valve and the opening of the mitral valve?
Isovolumetric relaxation
Which heart sound is also referred to as the atrial kick?
S4
With regard to auscultation of the heart, in what area is S1 loudest?
The mitral area (ie, the midclavicular line in the fifth intercostal space)
Which heart sound occurs during aortic and pulmonary valve closure?
S2
With regard to auscultation of the heart, in what area is S2 loudest?
The left sternal border
True or false: The presence of an S3 in children always indicates a cardiac defect.
False; S3 can be a normal finding in children and pregnant women
Which abnormal heart sound is associated with dilated congestive heart failure?
S3
Which abnormal heart sound is associated with a hypertrophic ventricle?
S4
Which abnormal heart sound occurs during rapid ventricular filling?
S3
Which heart sound occurs during mitral and tricuspid valve closure?
S1
In relation to the cardiac cycle, the C wave of the jugular venous pulse is associated with what contraction?
Right ventricle contraction (ie, the tricuspid valve bulging into the atrium)
In relation to the cardiac cycle, the V wave of the jugular venous pulse is associated with what?
Increased atrial pressure as a result of filling against the closed tricuspid valve
During a physical examination, what diagnostic sign may be observable in the neck of a patient with right heart failure?
Elevated jugular venous pressure
When listening to a normal heart, which valve closes first during S2: the aortic valve or the pulmonic valve?
The aortic valve
How is normal S2 splitting increased?
By inspiration
In which disorder is the paradoxical splitting of the S2 heart sound seen?
Aortic stenosis
Wide splitting of the S2 heart sound is associated with _____ stenosis.
Pulmonic
What is the name of the phenomenon that occurs when P2 (pulmonic valve) precedes A2 (aortic valve) in the heart sound S2?
Paradoxic splitting
During auscultation of a patient with aortic stenosis during inspiration, does the time period between pulmonic and aortic valvular closure increase or decrease?
Decrease; this is known as paradoxical splitting
During which phase is ventricular volume highest?
During atrial systole
During which phase is ventricular volume lowest?
During isovolumetric relaxation
_____ (Normal/Wide/Fixed/Paradoxical) splitting is seen in conditions that delay left ventricular emptying (ie, aortic stenosis and left bundle-branch block).
Paradoxical
Normal inspiration causes a _____ (increase/decrease) in intrathoracic pressure, which in turn causes _____ (increased/decreased) capacity for pulmonary blood flow.
Decrease; increased
_____ (Normal/Wide/Fixed/Paradoxical) splitting is seen in conditions that delay right ventricle emptying (ie, pulmonic stenosis and right bundle-branch block).
Wide
In normal splitting of the S2 heart sound, the pulmonic valve closes later during inspiration due to _____ (increased/decreased) blood flow in lungs, and the aortic valve closes earlier during inspiration due to _____ (increased/decreased) venous return to the left heart.
Increased; decreased
Regarding auscultation of the heart, in what areas are the murmurs of aortic stenosis and aortic regurgitation best heard?
The aortic area (ie, the right sternal border and the second intercostal space) and the left sternal border, respectively
In which phase of the cardiac cycle is the murmur of aortic stenosis heard?
Systole
Regarding auscultation of the heart, in what areas are the murmurs of pulmonic stenosis and pulmonic regurgitation best heard?
The pulmonic area (ie, the left sternal border at the second intercostal space) and the left sternal border, respectively
On which part of the chest are tricuspid valve murmurs best auscultated?
The tricuspid area (ie, the left sternal border at the fifth intercostal space)
Regarding auscultation of the heart, in what area is the murmur of a ventricular septal defect best heard?
The tricuspid area (ie, the left sternal border at the fifth intercostal space)
In which phase of the cardiac cycle is the murmur of tricuspid stenosis heard?
Diastole
On which part of the chest are mitral valve murmurs best auscultated?
The mitral area (ie, the midclavicular line at the fifth intercostal space)
In which phases of the cardiac cycle are the murmurs of mitral stenosis and mitral regurgitation heard?
Diastole and systole, respectively
In which phase of the cardiac cycle are the murmurs of aortic regurgitation and pulmonic regurgitation heard?
Diastole
With regard to auscultation of the heart, in what area is the murmur of an atrial septal defect best heard?
The tricuspid area (ie, the left sternal border at the fifth intercostal space)
Pulmonic flow murmurs and diastolic rumbles are commonly associated with which cardiac defect?
Atrial septal defects. The pulmonic flow murmur is due to increased flow through the pulmonary valve, and the diastolic rumble is due to increased flow across the tricuspid valve
With regard to auscultation of the heart, in what area are flow murmurs best heard?
The second intercostal space and both the left and right sternal borders
A murmur of hypertrophic cardiomyopathy occurs in the ______ phase of the cardiac cycle.
Systolic
With regard to auscultation of the heart, in what area is the murmur of hypertrophic cardiomyopathy best heard?
The left sternal border (generally)
Rheumatic fever can lead to which valve abnormality?
Mitral stenosis
Where is the murmur of mitral regurgitation the loudest?
At the apex
Compare the pressures in the left ventricle and aorta in a patient with aortic stenosis with those in a healthy patient.
In a patient with aortic stenosis, the pressure in the left ventricle is higher than the pressure in the aorta; the ventricle squeezes blood past a stenotic valve, thus the pressure before the valve (the ventricle) is higher than the pressure after the valve (in the aorta)
What are three examples of pathological processes that can cause mitral regurgitation?
Ischemic heart disease, mitral valve prolapse, and left ventricular dilatation
What type of murmur is loudest at the apex and radiates toward the axilla?
Mitral valve murmurs
What are two examples of pathological processes that can cause tricuspid regurgitation?
Right ventricular dilatation or endocarditis
What type of murmur is loudest at the left sternal border at the fifth intercostal space and radiates to the right sternal border?
Tricuspid regurgitation
A ventricular septal defect causes what type of murmur: late systolic, diastolic, or holosystolic?
Holosystolic
Which heart valve disease process can be associated with syncope?
Aortic stenosis
What type of murmur is holosystolic, harsh sounding, and loudest at the left sternal border at the fifth intercostal space?
Ventricular septal defect
Which heart murmur is described as a holosystolic, high-pitched, blowing murmur?
Mitral regurgitation
Murmurs due to valvular defects on the right side of the heart _____ (decrease/increase) in intensity on inspiration.
Increase
Which heart murmur is described as a late systolic murmur with midsystolic click?
Mitral prolapse
What is the most frequent murmur-causing valvular lesion?
Mitral prolapse
Which heart murmur is described as an immediate high-pitched, blowing, diastolic murmur?
Aortic regurgitation
Which heart murmur is usually benign, but can predispose to infective endocarditis?
Mitral prolapse
Which heart murmur can be accompanied by a wide pulse pressure?
Aortic regurgitation
Which heart murmur follows an opening snap?
Mitral stenosis
What are three examples of pathological processes that can cause aortic regurgitation?
Aortic root dilatation, bicuspid aortic valve, or rheumatic fever
Which heart murmur is described as a continuous, machine-like murmur?
Patent ductus arteriosus
Which heart murmur is described as a delayed, rumbling, late-diastolic murmur?
Mitral stenosis
Which heart chamber has the greatest increase in pressure above normal in a patient with mitral stenosis?
Left atrium
What does the term pulsus parvus et tardus mean?
Pulses are weak, and the strongest part of the peripheral pulse occurs late after the S1 is heard; this is because it takes a longer time for blood to cross the stenotic aortic valve to fill the vessels
Which heart murmur is described as a crescendo-decrescendo systolic murmur following an ejection click?
Aortic stenosis
To where does the aortic stenosis murmur radiate?
The carotid arteries
When a cardiac defect occurs on the left side of the heart, does the intensity of the corresponding murmur generally increase or decrease upon expiration?
Increase
What causes the increase in intensity upon expiration of a left-sided cardiac defect?
Increased blood flow into the left atrium
Match each of these conditions with one of the Starling curves: exercise; congestive heart failure (CHF); CHF plus digitalis
(A) exercise;
(B) CHF plus digitalis;
(C) CHF
What phase of the cardiac cycle is the period of highest O2 consumption?
(1) isovolumetric contraction: the period between mitral valve closure and aortic valve opening
What phase of the cardiac cycle corresponds to number (2)?
Systolic ejection: the period during which the aortic valve is open
What phase of the cardiac cycle corresponds to number (4)?
Rapid filling: right after the mitral valve opens
An asymptomatic 55-year-old woman has this electrocardiogram on a routine preoperative exam. Why are beats “missing”?
She has Mobitz type I (Wenckebach) second-degree atrioventricular block; the PR interval progressively lengthens until a beat is “dropped”
A 35-year-old man presents with palpitations and lightheadedness and has this electrocardiogram. What is he at risk for?
He has Mobitz type II second-degree atrioventricular block, which can progress to complete (third-degree) heart block
A 57-year-old man complains of crushing chest pain. He has this electrocardiogram in the ER. Compare the atrial and ventricular rates.
He has 3rd-degree (complete) atrioventricular block; the atrial rate is faster than the ventricular rate
A 64-year-old has crushing chest pain radiating to his L arm. He becomes unresponsive; electrocardiogram is as shown. Diagnosis? Treatment?
Ventricular fibrillation; CPR and defibrillation are the only treatments for this otherwise fatal arrhythmia
