Cardio PPT 3: cardiac cycle
Some cardiologists refer to the collective S1, S2, and S3 sounds as the
"Kentucky gallop," because they mimic those produced by a galloping horse. Lub dub up
S4 occurs prior to S1 and the collective sounds S4, S1, and S2 are referred to by some cardiologists as the
"Tennessee gallop"
When is the cardiac cycle complete?
- Blood flow into atria - AV valves open - semilunar valves close
Fluids, whether gases or liquids, are materials that flow according to pressure gradients—that is, they move from......
.... regions that are higher in pressure to regions that are lower in pressure. Accordingly, when the heart chambers are relaxed (diastole), blood will flow into the atria from the veins, which are higher in pressure. As blood flows into the atria, the pressure will rise, so the blood will initially move passively from the atria into the ventricles. When the action potential triggers the muscles in the atria to contract (atrial systole), the pressure within the atria rises further, pumping blood into the ventricles. During ventricular systole, pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle.
isovolumetric relaxation
1. At the beginning of the cardiac cycle, both the atria and ventricles are relaxed ATRIAL FILLING: Blood is flowing into the right atrium from the superior and inferior venae cavae and the coronary sinus; Blood flows into the left atrium from the four pulmonary veins. [MID ATRIAL DIASTOLE] [EARLY VENTRICULAR DIASTOLE]
phases of cardiac cycle
1. Isovolumetric relaxation - still early ventricular diastole - atrial diastole/passive filling 2. ventricular filling - passive filling 70-80% - late ventricular diastole 3. atrial contraction - atrial systole - active ventricular filling remaining 20-30% 4. ventricular/isovolumetric contraction - first phase ventricular systole - contraction causes increased pressure but not ejection 5. ventricular ejection - second phase ventricular systole - contraction overcomes artery pressures and ventricular blood is ejected
about how long is atrial systole?
100ms
ventricular filling
2. Passive VENTRICULAR FILLING: The two atrioventricular valves, the tricuspid and mitral valves, are both open, so blood flows unimpeded from the atria and into the ventricles. Approximately 70-80 percent of ventricular filling occurs by this method. At the end of atrial diastole and just prior to atrial contraction, the ventricles contain approximately 130 mL blood in a resting adult in a standing position. This volume is known as the end diastolic volume (EDV) or preload. [END ATRIAL DIASTOLE] [LATE VENTRICULAR DIASTOLE]
atrial contraction
3. Contraction of the atria follows depolarization, represented by the P wave of the ECG. As the atrial muscles contract from the superior portion of the atria toward the atrioventricular septum, pressure rises within the atria and blood is pumped into the ventricles through the open atrioventricular (tricuspid, and mitral or bicuspid) valves. Atrial contraction, also referred to as the "atrial kick," contributes the remaining 20-30 percent of ventricular filling. Atrial systole lasts approximately 100 ms and ends prior to ventricular systole, as the atrial muscle returns to diastole. [ATRIAL SYSTOLE] [END VENTRICULAR DIASTOLE]
ventricular/isovolumetric contraction
4. Ventricular systole follows the depolarization of the ventricles which is represented by the QRS complex in the ECG. It may be conveniently divided into two phases, lasting a total of 270 ms (contraction & ejection). Initially, as the muscles in the ventricle contract, the pressure of the blood within the chamber rises, but it is not yet high enough to open the semilunar (pulmonary and aortic) valves and be ejected from the heart. However, blood pressure quickly rises above that of the atria that are now relaxed and in diastole. This increase in pressure causes blood to flow back toward the atria, closing the tricuspid and mitral valves. Since blood is not being ejected from the ventricles at this early stage, the volume of blood within the chamber remains constant. [EARLY VENTRICULAR SYSTOLE] [EARLY ATRIAL DIASTOLE]
How long is ventricular diastole?
430ms
ventricular ejection
6. In the second phase of ventricular systole, the contraction of the ventricular muscle has raised the pressure within the ventricle to the point that it is greater than the pressures in the pulmonary trunk and the aorta. Blood is pumped from the heart, pushing open the pulmonary and aortic semilunar valves. Pressure generated by the left ventricle will be appreciably greater than the pressure generated by the right ventricle, since the existing pressure in the aorta will be so much higher. Nevertheless, both ventricles pump the same amount of blood. This quantity is referred to as stroke volume. Stroke volume will normally be in the range of 70-80 mL. Since ventricular systole began with an EDV of approximately 130 mL of blood, this means that there is still 50-60 mL of blood remaining in the ventricle following contraction. This volume of blood is known as the end systolic volume (ESV).
complete cardiac cycle is how long?
800ms
What is preload and its normal amount?
= EDV end diastolic volume ~ 130 ml
Heart murmurs are
A sound made by backflow of blood through either set of valve that cannot close or open properly. The term murmur is used to describe an unusual sound coming from the heart that is caused by the turbulent flow of blood. Murmurs are graded on a scale of 1 to 6, with 1 being the most common, the most difficult sound to detect, and the least serious. The most severe is a 6.
What happens when ventricular pressure is greater than aorta and pulmonary aa?
Blood is ejected from ventricles
Title: KAPLANPA0002 0002. Which of the following physical examination findings is associated with aortic stenosis? ©Kaplan A. Heave noted at point of maximal intensity B. Murmur which worsens with squatting C. Decreased carotid upstroke D. Wide pulse pressure E. Fixed splitting of S2
C. Decreased carotid upstroke
Ventricular systole follows?
Depolarization of ventricles
isovolumetric ventricular relaxation phase
During the early phase of ventricular diastole, as the ventricular muscle relaxes, pressure on the remaining blood within the ventricle begins to fall. When pressure within the ventricles drops below pressure in both the pulmonary trunk and aorta, blood flows back toward the heart, producing the dicrotic notch (small dip) seen in blood pressure tracings. The semilunar valves close to prevent backflow into the heart. Since the atrioventricular valves remain closed at this point, there is no change in the volume of blood in the ventricle, so the early phase of ventricular diastole is called the isovolumetric ventricular relaxation phase.
Six grades are used to classify the intensity of a murmur:
Grade I: - is the faintest murmur that can be heard (with difficulty; murmur usually softer than first [S1] and second heart sound [S2]) -> quiet room, listen for over a minute (AS in Golden Ret certification) Grade II: - murmur is also a faint murmur but has the same intensity as S1 and S2. -> student should hear Grade III: - murmur is louder than S1 and S2 without a palpable thrill. Hear! Grade IV: - murmur is loud and is associated with a palpable thrill. Feel! Grade V: - murmur is very loud with a thrill and can be heard with slightest touch of the stethoscope. Grade VI: - murmur is the loudest and can be heard without a stethoscope. Ick! The gradation of intensity is purely subjective. However, it allows recognition of changes in the intensity of the murmur, which has diagnostic relevance.
Late ventricular diastole
In the second later phase of ventricular diastole, as the ventricular muscle relaxes, pressure on the blood within the ventricles drops even further. Eventually, it drops below the pressure in the atria. When this occurs, blood flows from the atria into the ventricles, pushing open the tricuspid and mitral valves. As pressure drops within the ventricles, blood flows from the major veins into the relaxed atria and from there into the ventricles. Both chambers are in diastole, the atrioventricular valves are open, and the semilunar valves remain closed. The cardiac cycle is complete.
What is another name for the early phase of ventricular diastole?
Isovolumetric relaxation
S3 is the sound of
It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae.
Diastolic dysfunction
Preserved EF, normal EDV; ⬇compliance (stiff/thick = impaired filling) often 2° to myocardial hypertrophy. aging, valvular dz, hemochromatosis, constrictive pericarditis, sarcoidosis, fibrosis, amyloidosis, restrictive and hypertrophic cardiomyopathies, HTN with LV hypertrophy. S4 gallop
Define isovolumetric contraction
Pressure increase in ventricle but no blood ejected yet
What wave segment shows ventricular systole?
QRS
Systolic dysfunction
Reduced EF, ⬆EDV; ⬇contractility often 2° to ischemia/MI, chronic HTN, myocarditis, or dilated cardiomyopathy. S3 gallop
Ventricular relaxation, or diastole, follows what?
Repolarization of the ventricles
what are the basic heart sounds?
S1 = "lub" = AV valve close S2 = "dub" = Close semilunar valve S3 = "upp" = Blood slosh, tense chordae
"lub"
S1 = AV valve close
In a normal, healthy heart, there are only two audible heart sounds:
S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as a "lub," or first heart sound. S2 is the sound of the closing of the semilunar valves during ventricular diastole and is described as a "dub". In both cases, as the valves close, the openings within the atrioventricular septum guarded by the valves will become reduced, and blood flow through the opening will become more turbulent until the valves are fully closed. There is a third heart sound, S3, but it is rarely heard in healthy individuals. It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae. S3 may be heard in youth, some athletes, and pregnant women. If the sound is heard later in life, it may indicate congestive heart failure, warranting further tests.
"dub"
S2 = close semilunar valve
"upp"
S3 = blood slosh, tense chordae
A few individuals may have both S3 and S4, and this combined sound is referred to as
S7
Which ventricle pumps more blood volume?
Same! both pump the same amount of blood
What is the dichotic notch?
Semilunar valve closure and slight pressure drop
What wave shows ventricular diastole?
T wave
what are the general steps of the cardiac cycle?
The cardiac cycle begins with atrial systole and progresses to ventricular systole, atrial diastole, and ventricular diastole, when the cycle begins again. Correlations to the ECG in image complete cardiac cycle = 800ms
What happens during the early phase of ventricular diastole?
Ventricle relax; pressure drops
Ventricular Diastole
Ventricular relaxation, or diastole, follows repolarization of the ventricles and is represented by the T wave of the ECG. It too is divided into two distinct phases and lasts approximately 430 ms. 1. isovolumetric ventricular relaxation phase During the early phase of ventricular diastole, as the ventricular muscle relaxes, pressure on the remaining blood within the ventricle begins to fall. When pressure within the ventricles drops below pressure in both the pulmonary trunk and aorta, blood flows back toward the heart, producing the dicrotic notch (small dip) seen in blood pressure tracings. The semilunar valves close to prevent backflow into the heart. Since the atrioventricular valves remain closed at this point, there is no change in the volume of blood in the ventricle, so the early phase of ventricular diastole is called the isovolumetric ventricular relaxation phase. 2. Late ventricular diastole In the second later phase of ventricular diastole, as the ventricular muscle relaxes, pressure on the blood within the ventricles drops even further. Eventually, it drops below the pressure in the atria. When this occurs, blood flows from the atria into the ventricles, pushing open the tricuspid and mitral valves. As pressure drops within the ventricles, blood flows from the major veins into the relaxed atria and from there into the ventricles. Both chambers are in diastole, the atrioventricular valves are open, and the semilunar valves remain closed. The cardiac cycle is complete.
Grade VI murmur
Very loud, audible with stethoscope not in contact with chest, thrill palpable and visible
When do the AV valves close?
When blood flows back to atria due to increased pressure in the ventricle
Explain the high/low pressures in the heart during the cardiac cycle
When the heart chambers are relaxed (diastole), blood will flow into the atria from the veins, which are higher in pressure. As blood flows into the atria, the pressure will rise, so the blood will initially move passively from the atria into the ventricles. When the action potential triggers the muscles in the atria to contract (atrial systole), the pressure within the atria rises further, pumping blood into the ventricles. During ventricular systole, pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle.
When does blood flow from the atria into the ventricles?
When ventricular pressure becomes lower than atrial pressure
what heart diseases are associated with diastolic dysfunction?
aging, valvular dz, hemochromatosis, constrictive pericarditis, sarcoidosis, fibrosis, amyloidosis, restrictive and hypertrophic cardiomyopathies, HTN with LV hypertrophy.
During auscultation, it is common practice for the clinician to ask the patient to breathe deeply. This procedure not only allows for listening to airflow, but it may also
amplify heart murmurs. Inhalation increases blood flow into the right side of the heart and may increase the amplitude of right-sided heart murmurs. Expiration partially restricts blood flow into the left side of the heart and may amplify left-sided heart murmurs.
atrial "kick"
atrial contraction/systole
What does the P wave represent?
atrial depolarization
One of the simplest, yet effective, diagnostic techniques applied to assess the state of a patient's heart is
auscultation using a stethoscope.
Murmurs are a "whoosh" or "slosh" sound that indicate
backflow through the valves.
Grade I murmur
barely audible in a quiet room
A fourth heart sound, S4, results from the
contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. S4 occurs prior to S1 and the collective sounds S4, S1, and S2 are referred to by some cardiologists as the "Tennessee gallop," because of their similarity to the sound produced by a galloping horse with a different gait.
Grade II murmur
faint, immediately recognizable same intensity as S1/2
There is a third heart sound, S3, but it is rarely heard in
healthy individuals. It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae. S3 may be heard in youth, some athletes, and pregnant women. If the sound is heard later in life, it may indicate congestive heart failure, warranting further tests.
fluids move from what pressure to what pressure?
high to low
what heart diseases are associated with systolic dysfunction?
ischemia/MI, chronic HTN, myocarditis, or dilated cardiomyopathy.
Grade IV murmur
loud with palpable thrill
Stroke Volume (SV)
measurement of the amount of blood ejected from a ventricle in one contraction ~70-80ml = SV
Grade III murmur
moderately loud, easy to hear *without a thrust or thrill
Phonocardiograms or auscultograms can be used to
record both normal and abnormal heart sounds using specialized electronic stethoscopes.
Which valves open at the end of ventricular contraction?
semilunar
The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as......
the cardiac cycle. The period of contraction that the heart undergoes while it pumps blood into circulation is called systole. The period of relaxation that occurs as the chambers fill with blood is called diastole. Both the atria and ventricles undergo systole and diastole, and it is essential that these components be carefully regulated and coordinated to ensure blood is pumped efficiently to the body
The heart tone "dub," or S2 (A2+P2), is caused by
the closure of the aortic valve and pulmonary valve at the end of ventricular systole.
The heart tone "lub," or S1, is caused by
the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole.
What valves close preventing back-flow into the ventricles?
two semilunar valves: the pulmonary and aortic valves
S3 and S4 are a "ta" sound that indicates
ventricles that are either too weak or too stiff to effectively pump blood.
What happens to ventricular blood pressure during diastole?
ventricular BP drops
When do the semilunar valves open?
ventricular pressure increased enough to overcome isovolumetric contraction
Grade V murmur
very loud, heard with one corner of the stethoscope lifted off the chest wall, with palpable thrill
End Diastolic Volume (EDV)
volume of blood in each ventricle at end of ventricular diastole ~130mL = EDV
End Systolic Volume (ESV)
volume of blood remaining in each ventricle after systole ~50-60ml = ESV
when does blood flow into a chamber?
when the chamber is relaxed
The splitting of the second heart tone, S2, into two distinct components, A2 and P2, can sometimes be heard in
younger people during inspiration. During expiration, the interval between the two components shortens and the tones become merged
