Heart Failure
Robbins Basic Pathology
Chapter 11
Lecture Outline
Introduction and Definition
Epidemiology
Cardiac Physiology Revisit
Aetiology
Left Sided Heart Failure
Causes
Pathophysiology
Hemodynamic Changes
Signs and Symptoms
Right Sided Heart Failure
Clinical Features
I. Introduction
Definition: A state in which the heart cannot provide sufficient
cardiac output to maintain the basic metabolic needs of the
body*
Can involve the left side, right side or both sides of the heart
Usually the left side is affected first
It is commonly termed congestive heart failure (CHF) since
symptoms of increase venous pressure are often prominent
*In a minority of cases the heart is unable to cope with increased tissue
demands (high output failure)
Introduction cont.
Common end point of many cardiac and cardiovascular
diseases
Most heart failure is secondary to systolic dysfunction i.e.
deterioration of myocardial contractile function
20% to 50% is secondary to diastolic dysfunction i.e. heart
contract normally but unable to relax normally
Onset is usually insidious but can be acute occasionally
II. Epidemiology
Frequency
Age
0.3/1000
< 45
3/1000
45-65
10/1000
>65
Increases with Age
Morbidity & Mortality
Dramatically Affects Quality and Length of Life
5 Year Mortality : Males
: Females
6 Year Mortality : Both Sexes
62%
42%
75%
Epidemiology
US Health and Human Services
5 million Americans suffer from CHF
$17.8 billion spent annually
400,000 new cases reported each year
III. Cardiac Physiology Revisited
Frank-Starling Mechanism
Cardiac Output
Stroke Volume x Heart Rate
Preload
Volume of Blood Delivered to Heart during Diastole (EDV)
1o Venous and Diastolic Function
Relationship between the EDV and force of contraction
Within limits, the greater the EDV, the greater the contraction during
systole (Frank-Starling Law)
Afterload
The pressure that must be overcome before a semilunar valve opens
Peripheral Vascular Resistance (1o arterial and systolic function)
IV. Aetiology: General Principles
Pathophysiological Causes
Inappropriate (increase) work load
Volume overload
Pressure overload
Myocardial dysfunction, myocyte loss
Decreased ventricular filling
In a mechanistic sense the heart is unable to pump blood delivered to
it by the venous circulation
inadequate CO i.e. forw ard failure
This is almost always followed by venous congestion
i.e. back w ard failure
Aetiology: General Principles cont.
Heart failure is a common end point for many diseases of the
heart and cardiovascular system (CVS)*
Ischaemic heart disease (IHD), myocardial infarction (MI)
Congenital heart disease
Hypertensive heart disease
Valvular heart disease
Primary myocardial disease
Pericardial disease
Heart disease secondary to intrinsic lung disease
Tachyarrhythmia
*R eview Heart Diseases
Causes of Heart Failure
Damage to the Heart and/or *Increase Workload
Coronary artery disease
IHD
Myocardial infarction (MI)
Heart muscle diseases
Cardiomyopathy (dilated, hypertrophic, restrictive)
Myocarditis (inflammatory, metabolic, immunologic)
*High blood pressure
*Abnormal heart valves (AS, AI, MI)
*Aortic coarctation
Causes of Heart Failure cont.
Other Causes
Congenital heart defects eg. ASD,VSD, PDA (shunted blood)
Pericardial disease eg. constrictive pericarditis (diastolic failure)
Severe lung parenchymal/vascular disease pulmonary
hypertension ( cor pulmonale)
Abnormal heart rhythms eg. atrial and ventricular fibrillation
(uncoordinated and inefficient contraction)
Diabetes mellitus (multiple effects)
Severe anemia (high output failure), hyperthyroidism
Causes of Heart Failure cont.
Coronary Artery Disease and MI
Ischaemia, necrosis, healing by fibrosis
Muscle weakness
Hypertension
Heart must pump harder to keep blood
circulating ( load)
hypertrophy, dilatation (decompensation)
Uncontrolled high blood pressure doubles the
risk of developing heart failure
Causes of Heart Failure cont.
Abnormal Heart Valves
Heart Muscle Disease
Rheumatic or infective endocarditis
Regurgitate and/or stenotic valves
Dilated cardiomyopathy impairment of contractility
systolic dysfunction
Hypertrophic and restricitve cardiomyopathy impairment of
compliance diastolic dysfunction
Myocarditis - drugs, alcohol, infections
Congenital Heart Disease
Eg. ASD, VSD, PDA
Abnormal shunts Volume overload
Causes of Heart Failure cont.
Severe Lung Disease
Intrinsic disease of the lung parenchyma and/or
vasculature chronic pulmonary hypertension
Chronic obstructive or interstitial lung disease
Recurrent pulmonary emboli
Primary, idiopathic pulmonary hypertension
Abnormal Heart Rhythm
If the heart beat is too fast, too slow or irregular it
may not be able to pump enough blood to the body
Causes of Heart Failure cont.
Diabetes: Tend to have other conditions that make the
heart work harder
Obesity
Hypertension
High cholesterol
Severe anemia
Inadequate number of red blood cells to carry oxygen
tachycardia and workload for the heart
Hyperthyroidism
Body metabolism is increased and overworks the heart
V. Left Ventricular Failure (LVF)
Pathophysiology and Causes
Volume over load * : Regurgitate valve eg. aortic incompetence (AI)
High output status eg. severe anaemia
Pressure overload * : Systemic hypertension
Outflow obstruction eg. aortic stenosis (AS)
Loss of muscles
: Impairment of contractility eg. post MI, chronic
ischaemia, cardiomyopathy, myocarditis
Restricted Filling
: Impairment of compliance eg. constrictive
pericarditis, restrictive cardiomyopathy
Tachyarrhythmia
* i.e. inappropriate increase in workload
LVF: Pathophysiologic Changes
Hemodynamic Changes
Neurohormonal Changes
Redistribution of Blood to the Brain
Cellular Changes
LVF: Pathophysiology
Hemodynamic Changes
Hemodynamic Changes: From the hemodynamic stand point HF
can be secondary to:
Systolic dysfunction
Diastolic dysfunction
In either case, blood may back up in the lungs causing fluid to
leak into the lungs (pulmonary edema)
Fluid may also build up in tissues throughout the body
Lower limb edema
Ascites
Sacral edema
LVF: Pathophysiology
Neurohormonal (NH) Changes
NH Changes
Favorable Effect
Unfavorable Effect
Sympathetic activity*
n-epinephrine
HR , contractility
Vasoconstn Venous
return (VR)
VR diastolic filling
Arteriolar constriction
after load workload
O2 consumption
Renin-AngiotensinAldosterone*
Salt & water retention
VR
VR diastolic filling
Vasoconstriction
after load (i.e. peripheral
resistance)
Vasopressin*
Water retention VR
a/a
atrial natriuretic
peptide (ANP)
Natriuresis, diuresis,
vasodilatation alleviate
pressure or volume overload
Endothelin
Vasoconstriction VR
a/a
*Review physiology of BP control
After load
Pathophysiology : Myocardial Structural
and Cellular Changes
Hypertrophy of myocytes
May be able to maintain CO in the face of worsening heart function
With sustained or worsening heart function structural and functional
abnormalities occur
Changes in Ca++ handling
Changes in adrenergic receptors
Slight in 1 receptors
1 receptors desensitization followed by down regulation
Changes in contractile proteins
Program cell death (Apoptosis)
Increase amount of fibrous tissue
Compensatory Mechanisms to Failure
Increased Heart Rate and Contractility
Dilation
Sympathetic = Norepinephrine
Frank Starling = Contractility
Neurohormonal
Redistribution of Blood to the Brain
Decompensation
Increased Pulmonary Venous Pressure
Interstitial Edema
Alveolar Edema
Morphology: Pulmonary Congestion and
Edema
Congestive Heart Failure Vicious Cycle
Low Output
Preload
4B
Salt/H2O
3B
After load
n-epinephrine
4A
Renal blood flow
Vasoconstriction
3A
Note: Preload = diastolic volume
After load = peripheral resistance
Renin
Angiotensin
Aldosterone
Signs and Symptoms of Left Heart Failure
Shortness of breath (SOB),
orthopnea, paroxysmal
nocturnal dyspnea (PND)
Cough
Low cardiac output
symptoms
Abdominal symptoms:
Anorexia, nausea
Abdominal fullness
Right hypochondrial pain
Signs and Symptoms of Heart
Failure
Shortness of Breath (Dyspnea)
WHY?
Blood backs up in the pulmonary veins because the
heart is unable to keep up with the supply
hydrostatic pressure
Fluid leaks into the lungs (pulmonary edema)
SYMPTOMS
Dyspnea on exertion or at rest
Difficulty breathing when lying flat (orthopnea)
Waking up due to attacks of severe shortness of breath
(PND)
Signs and Symptoms of Heart
Failure
Persistent Cough or Wheezing
WHY?
Fluid backs up in the lungs (fluid transudation into air
spaces)
SYMPTOMS
Coughing that produces white or pink blood-tinged
sputum
Signs and Symptoms of Heart
Failure
Edema
WHY?
Decreased blood flow out of the weak heart
Blood returning to the heart from the veins backs up
hydrostatic pressure fluid to leak out into tissues
SYMPTOMS
Swelling in feet, ankles, legs or abdomen
Weight gain
Signs and Symptoms of Heart
Failure
Tiredness, Fatigue
WHY?
Heart is unable to pump enough blood to meet needs
of bodies tissues
Body diverts blood away from less vital organs
(muscles in limbs) and sends it to the heart and brain
SYMPTOMS
Constant tired feeling
Difficulty with everyday activities
Signs and Symptoms of Heart
Failure
Lack of Appetite / Nausea
WHY?
The digestive system receives less blood causing
problems with digestion
SYMPTOMS
Feeling of being full or sick to the stomach
Signs and Symptoms of Heart
Failure
Confusion / Impaired Thinking
WHY?
Water electrolyte disturbances (sodium)
SYMPTOMS
Memory loss or feeling of disorientation
Relative or caregiver may notice this first
Signs and Symptoms of Heart
Failure
Increased Heart Rate
WHY?
The heart beats faster to make up for the loss in
pumping function
SYMPTOMS
Heart palpitations
May feel like the heart is racing or throbbing
New York Heart Association (NYHA)
Functional Classification
Class
% of
patients
Symptoms
35%
No symptoms or limitations in ordinary physical activity
II
35%
Mild symptoms and slight limitation during ordinary
activity
III
25%
Marked limitation in activity even during minimal
activity. Comfortable only at rest
IV
5%
Severe limitation. Experiences symptoms even at rest
Physical Signs: General
Pale and anxious
Cold, clammy skin
Breathless
Edema of lower extremities
May be confused
May have cyanosis
Physical Signs: CVS and Lung
High diastolic BP and occasional decrease in systolic BP
(decapitated BP)
Increased heart rate
Displaced and sustained apical impulse (enlarged heart)
Rales (Inspiratory)
Systolic murmur due to atrial regurgitation
Third heart sound low pitched sound that is heard
during rapid filling of ventricle
Forms of Heart Failure
Systolic vs Diastolic (see next slide)
Acute vs Chronic
Acute - Large MI, aortic valve dysfunction
Chronic - CHF usually chronic
The heart tries to compensate for the loss in
pumping function by muscle mass (hypertrophy)
and heart rate
High Output Failure
Pregnancy, severe anemia, thyrotoxisis, A/V fistula, beriberi,
Pagets disease
Forms of heart failure cont.
Right vs Left Sided Heart Failure
Left Heart Failure :
Involves the left ventricle
Systolic failure
The heart loses the ability to contract / pump blood into
the circulation
Diastolic failure
The heart loses the ability to relax because it becomes
stiff
Unable to fill properly between each beat
Forms of heart failure cont.
Left Heart Failure
Systolic and Diastolic Failure cont.
In both types, blood may back up in the lungs causing
fluid to leak into the lungs (pulmonary edema)
Fluid may also build up in tissues throughout the body
(edema)
Forms of heart failure cont.
Right Heart Failure
Right sided heart failure:
Usually presents with:
M ost com m on cause is
left sided failure
Lower limb/ankle edema
Ascites
Occasionally isolated right
heart failure can be due to
Hepatic congestion
- Pulmonary embolisms
- Other causes of
pulmonary hypertension
- Rt Ventricular infarction
- Mitral stenosis
Cardiac cirrhosis (in the
long run)
Minimal or no pulmonary
congestion or edema
Laboratory Investigations
CXR - Single most useful
clinical tool
EKG - Non Specific
Lab - Non Specific
Principles of Managment
Correction of reversible causes (treat underlying
cause)
Myocardial ischemia
Valvular heart disease
Thyrotoxicosis and other high output status
Shunts
Arrhythmia
Principles of Management cont.
Life Style Change: Diet and Activity
Salt restriction
Fluid restriction
Daily weight (tailor therapy)
Gradual exertion programs
Medications
Diuretics
Inhibitors of the renin-angiotensin-aldosterone system
Digitalis
-blokers
Vasodilators
Ionotropic agents
