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Normal Heart Function
and
Congestive Heart Failure
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Basic Concepts:
The Cardiac Cycle
 Myocardial Filling -- “Diastole”
Compliance
Left ventricular filling curves
 Myocardial Emptying -- “Systole”
Cardiac Output
Frank-Starling Performance Curves
 The relationship of filling and emptying:
Pressure - Volume Loops

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Basic Definitions

Cardiac Output is
defined as:
Stroke Volume
X
Heart Rate
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
Blood Pressure is
defined as:
Cardiac Output
X
Systemic Vascular
Resistance
What happens to each of these during:
Exercise?
When LV filling is impaired??
When systolic function is impaired???
What happens to the runner
during exercise?
OR
“Why the jogger didn’t blow his top!”
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Basic Definitions

Cardiac Output is
defined as:
Stroke Volume
X
Heart Rate
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
Blood Pressure is
defined as:
Cardiac Output
X
Systemic Vascular
Resistance
Basic Concepts:
The
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#1
Cardiac Cycle
The Normal Cardiac Cycle
Components of Diastole:
Isovolumic relaxation
Rapid Ventricular filling
Atrial contraction (“kick”)
 Components of Systole
Isovolumic contraction
L.V. Ejection

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Volume change during LV filling
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The Normal Cardiac Cycle

Let’s take a look at the cycle in some
depth............
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The Cardiac Cycle
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Basic Concepts:
#2
The Cardiac Cycle
 Myocardial Filling -- “Diastole”
Compliance
Left ventricular filling curves
 Myocardial Contractility -- Systole
Frank-Starling Performance Curves
 The relationship of filling and emptying:
Pressure - Volume Loops

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Left ventricular filling curves


Relationship of pressure to
volume defines L.V. “stiffness”
or “non-compliance”
At low pressures, almost linear
Pressure (m m Hg)
Y
40
30
20
10
0
V o lu m e (m l)
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Relationships to Remember

“Compliance” is
proportional to
change in volume
over
change in pressure
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

“Stiffness” is the
inverse.
Stiffness is
proportional to
change in pressure
over
change in volume
Normal vs “non-compliant” LV
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Basic Concepts:
#3
The Cardiac Cycle
 Myocardial Filling -- “Diastole”
Compliance
Left ventricular filling curves
 Myocardial Emptying -- “Systole”
Cardiac Output
Frank-Starling Performance Curves
 The relationship of filling and emptying:
Pressure - Volume Loops
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
Mediators of Cardiac Output
CARDIAC OUTPUT
Heart Rate
Preload
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Stroke Volume
Afterload
Contractility
Relationships to Remember
“Preload” and “afterload” are defined as
the wall tension during diastole and
systole, respectively
 Wall tension is defined as:

Pxr
2h
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(where h = wall thickness)
Preload
Is the wall tension during ventricular
filling
 Is defined as
Pxr
2h

during diastole!!!
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Why is volume the most
important determinant of
ventricular preload??
(Hint: look at the cardiac cycle)
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The Cardiac Cycle
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Afterload
Is the wall tension during ventricular
ejection
 Is defined as:
Pxr
2h

during systole!!!
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Why is systolic pressure the
most important determinant of
ventricular afterload???
(Hint: look again at the cardiac cycle)
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The Cardiac Cycle
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How do we relate myocardial
performance to:

Loading conditions: i.e. preload and
afterload
And how does “myocardial contractility”
relate to all of the above??
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Frank - Starling Curves
7

L.V. “performance”
curves relating:
1.
L.V.E.D.P.
(i.e." preload”)
2.
L.V. “performance”
(i.e. cardiac output)
6
Cardiac Output
or stroke volume
5
4
3
2
1
0
L .V . e n d - d ia s t o lic p r e s s u r e
o r e n d - d ia s t o lic v o lu m e
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Frank-Starling Curves in CHF
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What happens to:




Heart rate
Blood pressure
Cardiac output
Vascular resistance

When:

LV filling falls
LV systolic function
is impaired
The LV is noncompliant
Afterload increases



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How do we measure.....
?
Blood pressure
 Cardiac output
 Stroke volume
 LVEDP
 Systemic vascular resistance

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The Swan-Ganz Catheter
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Werner Forssman – 1929
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Right heart catheterization
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Right Heart Catheterization
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Measuring Cardiac Output

Fick Method --
O2 consumption
A-V O2 difference
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
Thermodilution
method -“The Black Box”
The Fick Principle
Lungs
O2
Body
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Measuring O2 consumption
The Waters Hood
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The Thermodilution Method
Similar in principle to the Fick method
 Uses change in temperature per unit
time, rather than change in O2
saturation
 Requires a thermal probe in the right
side of the heart

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Construction of Starling Curve for
an individual patient
7
6
Cardiac Output
or stroke volume
5
4
3
2
1
0
L .V . e n d - d ia s t o lic p r e s s u r e
o r e n d - d ia s t o lic v o lu m e
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Pressure - Volume Loops

Pressure
(mm Hg)

Vo lum e (m l)
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Relate L.V. pressure
to L.V. volume in a
single cardiac cycle
Can be used to
explore the effects of
various therapies on
stroke volume and
L.V.E.D.P.
Pressure - Volume Loops


Holding afterload
and contractility
constant
Varying “preload”,
measured as enddiastolic volume
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Heart Failure
Forward Failure:
Inability to pump blood forward to meet the
body’s demands
Backward Failure:
Ability to meet the body’s demands, at the
cost of abnormally high filling pressures
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Systolic vs. Diastolic Dysfunction

Systolic dysfunction
• Decreased stroke volume
• Decreased forward cardiac output
• Almost always associated with diastolic
dysfunction as well

Diastolic Dysfunction
• One third of patients with clinical heart
failure have normal systolic function – i.e.
“pure” diastolic dysfunction
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Impa ire d Co ntra c tility
1.
2.
3.
4.
Pre s s ure Ove rlo a d
Myo c a rdia l Infa rc tio n
Tra ns ie nt myo c a rdia l is c he mia
Chro nic Vo lume o ve rlo a d
Dila te d Ca rdio myo pa thy
1 . Ao rtic S te no s is
2 . Unc o ntro lle d hype rte ns io n
L.V. Sys tolic dys func tion
Left Heart Failure
L.V. Dia s to lic dys func tio n
1.
2.
3.
4.
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Le ft ve ntric ula r hype rtro phy
Hype rtro phic c a rdio myo pa thy
Re s tric tive c a rdio myo pa thy
Tra ns ie nt myo c a rdia l is c he mia
Obs truc tio n o f L.V. filling
1 . Mitra l S te no s is
2 . Pe ric a rdia l c o ns tric tio n o r
ta mpo na de
Impaired Contractility
Pre s s ure Ove rlo a d
1. Myocardial Infarction
2. Transient myocardial ischemia
3. Dilated Cardiomyopathy
4. Chronic Volume overload
1 . Ao rtic S te no s is
2 . Unc o ntro lle d hype rte ns io n
L.V. Sys tolic dys func tion
Left Heart Failure
L.V. Dia s to lic dys func tio n
1.
2.
3.
4.
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Le ft ve ntric ula r hype rtro phy
Hype rtro phic c a rdio myo pa thy
Re s tric tive c a rdio myo pa thy
Tra ns ie nt myo c a rdia l is c he mia
Obs truc tio n o f L.V. filling
1 . Mitra l S te no s is
2 . Pe ric a rdia l c o ns tric tio n o r
ta mpo na de
Pre s s ure Ove rlo a d
Impa ire d Co ntra c tility
1.
2.
3.
4.
Myo c a rdia l Infa rc tio n
Tra ns ie nt myo c a rdia l is c he mia
Chro nic Vo lume o ve rlo a d
Dila te d Ca rdio myo pa thy
1 . Ao rtic S te no s is
2 . Unc o ntro lle d hype rte ns io n
L.V. Sys tolic dys func tion
Left Heart Failure
L.V. Dia s to lic dys func tio n
1.
2.
3.
4.
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Le ft ve ntric ula r hype rtro phy
Hype rtro phic c a rdio myo pa thy
Re s tric tive c a rdio myo pa thy
Tra ns ie nt myo c a rdia l is c he mia
Obs truc tio n o f L.V. filling
1 . Mitra l S te no s is
2 . Pe ric a rdia l c o ns tric tio n o r
ta mpo na de
Pre s s ure Ove rlo a d
Impa ire d Co ntra c tility
1.
2.
3.
4.
Myo c a rdia l Infa rc tio n
Tra ns ie nt myo c a rdia l is c he mia
Chro nic Vo lume o ve rlo a d
Dila te d Ca rdio myo pa thy
1 . Ao rtic S te no s is
2 . Unc o ntro lle d hype rte ns io n
L.V. Sys tolic dys func tion
L.V. Diastolic dysfunction
Left Heart Failure
L.V. Dia s to lic dys func tio n
1.
2.
3.
4.
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Le ft ve ntric ula r hype rtro phy
Hype rtro phic c a rdio myo pa thy
Re s tric tive c a rdio myo pa thy
Tra ns ie nt myo c a rdia l is c he mia
Obs truc tio n o f L.V. filling
1 . Mitra l S te no s is
2 . Pe ric a rdia l c o ns tric tio n o r
ta mpo na de
Diastolic Dysfunction

Impaired early diastolic relaxation
(this is an active, energy dependent process)

Increased stiffness of the left ventricle
(this is a passive phenomenon)
• LVH
• LV fibrosis
• Restrictive or infiltrative cardiomyopathy
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Diastolic dysfunction due to LVH
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Diastolic dysfunction:
Pressure – Volume Loop
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Impa ire d Co ntra c tility
1.
2.
3.
4.
Pre s s ure Ove rlo a d
Myo c a rdia l Infa rc tio n
Tra ns ie nt myo c a rdia l is c he mia
Chro nic Vo lume o ve rlo a d
Dila te d Ca rdio myo pa thy
1 . Ao rtic S te no s is
2 . Unc o ntro lle d hype rte ns io n
L.V. Sys tolic dys func tion
Left Heart Failure
L.V. Dia s to lic dys func tio n
1.
2.
3.
4.
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Le ft ve ntric ula r hype rtro phy
Hype rtro phic c a rdio myo pa thy
Re s tric tive c a rdio myo pa thy
Tra ns ie nt myo c a rdia l is c he mia
Obs truc tio n o f L.V. filling
1 . Mitra l S te no s is
2 . Pe ric a rdia l c o ns tric tio n o r
ta mpo na de
Compensatory Mechanisms for
Heart Failure
Frank – Starling Mechanism
 Neuro-humoral alterations
 Left ventricular enlargement

• LV Hypertrophy  ↑ contractility
• LV “remodeling”  ↑ stroke volume
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Frank –Starling mechanism
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Neuro-humoral mediators
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Neuro-humoral mediators
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Left Ventricular enlargement

Concentric LVH
• Increased LVEDP
• Increased incidence
of backward failure
• Decreased wall
stress at expense of
increased oxygen
demand and
increased LVEDP
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
Eccentric hypertrophy
(cavity dilation and hypertrophy)
• Seen in volume-overload
states
• Seen after acute MI
(post-infarction “remodeling”)
• Increased stroke volume
at the expense of
increased wall stress,
oxygen demand and
LVEDP
End results of “compensatory mechanisms”
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Impa ire d Co ntra c tility
1.
2.
3.
4.
Pre s s ure Ove rlo a d
Myo c a rdia l Infa rc tio n
Tra ns ie nt myo c a rdia l is c he mia
Chro nic Vo lume o ve rlo a d
Dila te d Ca rdio myo pa thy
1 . Ao rtic S te no s is
2 . Unc o ntro lle d hype rte ns io n
L.V. Sys tolic dys func tion
Left Heart Failure
L.V. Dia s to lic dys func tio n
1.
2.
3.
4.
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Le ft ve ntric ula r hype rtro phy
Hype rtro phic c a rdio myo pa thy
Re s tric tive c a rdio myo pa thy
Tra ns ie nt myo c a rdia l is c he mia
Obs truc tio n o f L.V. filling
1 . Mitra l S te no s is
2 . Pe ric a rdia l c o ns tric tio n o r
ta mpo na de
“Pseudo” Left Heart Failure
Abnormally high filling pressure (PCW pressure)
despite normal LV function and LVEDP
Obstruction of L.V. filling
Mitral Stenosis
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Right Heart Failure

Very commonly a
sequela of Left Heart
Failure

•
LVEDP
•
PCW
•
PA pressure
• Right heart pressure
overload

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Cardiac causes
• Pulmonic valve stenosis
• RV infarction
Parenchymal pulmonary
causes
• COPD
• ILD

Pulmonary vascular disease
• Pulmonary embolism
• Primary Pulmonary
hypertension
Right heart vs. Left heart failure
Left Heart failure
•
•
Pulmonary congestion
Reduced forward
cardiac output:
•
•
•
•
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Fatigue
Renal insufficiency
Cool extremities
Decreased mentation
Right Heart failure
•
•
•
•
Neck vein distension
Hepatic congestion
Peripheral edema
Also may result in
reduced forward cardiac
output, but with clear
lung fields