Flashcards in Cardiac Deck (133)
What causes the first (S1) and second (S2) heart sound?
1st: closure of the mitral and tricuspid valves at the beginning of systole.
2nd: closure of the aortic and pulmonic valves (semilunar valves) at the beginning of diastole
An S3 heart sound is an indicator of what condition?
An S3 heart sound (gallop rhythm) during mid-diastole is most often heard in the context of CHF.
What is the postulated mechanism (s) that produces an S3 heart sound?
-S3 is thought to reflect a flaccid and inelastic condition of the heart during diastole (Stoelting)
-Guyton says: a logical but unproven explanation of this sound (S3) is oscillation of blood back and forth between the walls of the ventricles initiated by inrushing blood from the atria
*Describe the murmurs heard, and specify the stethoscope location where they are best heard, if the patient has mitral stenosis. If the patient has mitral regurgitation.
-mitral stenosis is recognized by the characteristic opening snap that occurs early in diastole and by a rumbling diastolic murmur, best heard with the chest piece placed over the cardiac apex.
-cardinal feature of mitral regurgitation is a blowing pansystolic (heard throughout systole) murmur, best heard with the chest piece placed over the cardiac apex.
*Describe the murmurs heard, and specify the stethoscope location where they are best heard, if the patient has aortic stenosis. If the patient has aortic regurgitation.
-aortic stenosis is recognized by its characteristic systolic murmur, best heard in the second right intercostal space with transmission into the neck
-aortic regurgitation is recognized by its diastolic murmur, best heard in the second right intercostal space
How is aortic valvular regurgitation graded?
severity is graded angiographically after contrast injection into the aortic root as follows:
1+= small amount of contrast material enters left ventricle during diastole, but is cleared from left ventricle during systole
2+= left ventricle is faintly opacified by contrast media during diastole and not cleared during systole
3+= left ventricle is progressively opacified
4+= left ventricle is completely opacified during the first diastole and remains so for several beats
NOTE: there are 4 grades for aortic valvular regurgitation reflecting the severity of the problem
What left heart valve problems cause diastolic murmurs?
What left heart valve problems cause systolic murmurs?
-aortic regurgitation and mitral stenosis are associated with diastolic murmurs
-aortic stenosis and mitral regurgitation are associated with systolic murmurs
Which left heart valve problems can best be auscultated to the right of the sternum in the second intercostal space?
Which valve problems can best be auscultated at the cardiac apex?
-aortic stenosis or aortic regurgitation can best be auscultated in the second intercostal space
-mitral stenosis and mitral regurgitation are best auscultated at the apex of the heart
What is the problem if the newborn has a systolic and a diastolic murmur?
The patient with patent ductus arteriosus has both systolic and diastolic murmur
A patient is in CHF, and you are listening to the heart sounds. What should be heard? Where on the chest should this be heard?
An S3 gallop should be heard if the patient is in CHF. Left sided S3 is best heard with the bell piece of the stethoscope at the left ventricular apex during expiration and with the patient in the lateral position. Right sided S3 is best heard at the left sternal border or just beneath the xiphoid and is increased with inspiration.
What dysrhythmia is most commonly observed in the patient with mitral stenosis?
What dysrhythmia in the patient is most likely to occur with mitral valve regurgitation?
Premature ventricular beats
*With atrial flutter, atrial fibrillation, or junctional rhythms a portion of left ventricular filling is lost; what percent of left ventricular end diastolic volume is normally contributed by atrial contraction (atrial kick or atrial priming)?
passive diastolic filling usually accounts for 75% of LV filling, with atrial contraction causing an additional 25% filling of ventricles
- Stoelting states: during the latter portion of diastole, the atria contract to deliver about 30% of the blood that normally enters the ventricle during each cardiac cycle
What is the normal range for stroke volume in ml in a 70kg male? Write the formula for stroke index (SI). What is the normal range for stroke volume index?
-normal range for SV is 60-90ml
-stroke index is stroke volume (SV) divided by body surface area (BSA) in meters squared; so, SI= (SV) (BSA)
-normal range for SV index is 40-60 ml/beat/m2
Define ejection fraction, and state its normal range.
EF is the ratio of SV (end-diastolic volume minus end-systolic volume) to end-diastolic volume
*EF= SV/EDV= (EDV-ESV)/EDV
-normal range is 0.6-0.8, or 60-80%
What are the two determinants of cardiac output? If stroke volume is 70ml and HR is 70bpm what is the CO?
-SV and HR are the two determinants of CO
-CO= SV x HR
-with a stroke volume of 70ml and a HR of 70bpm, CO is 70ml/beat x 70bpm= 4900ml/min-4.9liters/min
What is the cardiac output in liters/min for a healthy 70kg person? In mL/kg/min?
CO is normally 5L/min
-CO in mL/kg/min is calculated as follows:
5L/min= 5,000ml/min= 5,000ml/70kg/min (assume 70kg person)= 71.43ml/kg/min
Remember you may be asked to convert a normal value to a per kg.
What is cardiac index? What is the normal range for cardiac index?
CI is CO divided by body surface area in meters squared. CI= CO/BSA
-normal CI ranges from 2.5-4.0 l/min/m2
Starlings law of the heart relates ventricular filling during diastole to what?
Starlings law of the heart relates ventricular filling during diastole to the amount of blood ejected during systole.
-the greater the ventricular filling during diastole (> the preload), the greater the quantity go blood pumped into the aorta during systole.
Describe the process at causes ventricular myocyte relaxation (lusitropy).
Ventricular myocyte contraction requires increased intracellular calcium.
Thus, for the ventricular myocyte to relax, intracellular calcium must be reduced back to resting levels.
-calcium is sequestered in the sarcoplasmic reticulum (SR) through energy-dependent processes.
Name the five organs in the vessel rich group. What percent of cardiac output goes to each of these organs?
1- brain (15%)
2- kidney (20%)
3- liver (25%)
4- lungs (100%)
5- heart (4-5%, 225ml/min)
What percent of the right hearts CO traverses the pulmonary circulation? Bronchial circulation?
100% of blood pumped by the right heart traverses pulmonary circulation and 0% traverses the bronchial circulation
What percent of the left hearts output traverses the bronchial circulation? Vessels delivering blood to the bronchial circulation arise from what arteries?
1-2% of the left hearts output traverses the bronchial circulation.
The bronchial circulation arises from the thoracic aorta and intercostal arteries.
In words, describe where isovolumetric relaxation occurs on the left ventricular pressure volume loop.
Isovolumetric relaxation occurs from the closure of the aortic valve to the opening of the mitral valve on the left ventricular pressure volume loop.
In words, describe where isovolumetric contraction occurs on the left ventricular pressure volume loop.
Isovolumetric contraction occurs from closure of the mitral valve to opening of the aortic valve on the left ventricular pressure volume loop
What is the range of normal pressures in each chamber of the heart?
What is the normal range of values for pulmonary capillary wedge pressure?
normally, PCWP= 5-15mmHg
What is the normal value for mean pulmonary artery pressure? For pulmonary artery systolic and diastolic pressures?
mean pulmonary artery pressure normally is about 16mmHg; systolic/diastolic pressures average 25/8mmHg
What is the normal value for mean systemic arterial pressure?