Download Cardiac Pathophysiology

Cardiac Pathophysiology
1
Disorders of Pericardium
2
I. Pericarditis
• Often local manifestation (indication) of
another disease
• May present as:
1. Acute pericarditis
2. Pericardial effusion
3. Constrictive pericarditis
3
1. Acute Pericarditis
• Acute inflammation of the pericardium
• Cause often unknown, but commonly caused by
– infection,
– uremia (renal failure),
– neoplasm (tumor),
– myocardial infarction (heart attack),
– surgery or trauma.
• Membranes become inflamed and
roughened, and exudate may develop
4
Symptoms:
• Sudden onset of severe chest pain that
becomes worse with respiratory movements
and with lying down.
• anterior chest pain may radiate to the back.
• May be confused initially with acute
myocardial infarction
• Also report dysphagia (difficulty in swallowing;
restlessness, irritability, anxiety, weakness
and malaise, body discomfort.
5
Signs
• low grade fever
• sinus tachycardia
• Friction rub (sandpaper sound)
may be heard at cardiac apex
and left sternal border and is
diagnostic for pericarditis (but
may be intermittent or irregular)
• ECG changes reflect
inflammatory process through
PR segment depression and
ST segment elevation.
6
The "P wave presents atrial activation; the P-R interval is the time from onset of
atrial activation to onset of ventricular activation. The QRS complex represents
ventricular activation; the QRS duration is the duration of ventricular
activation. The ST-T wave represents ventricular repolarization. The QT interval
is the duration of ventricular activation and recovery. The U wave probably
represents 'after depolarizations' of the ventricles"7
Treatment
• Treat symptoms
• Look for underlying cause
• If pericardial effusion develops, aspirate excess
fluid
• Acute pericarditis is usually self-limiting,
but can progress to chronic constrictive
pericarditis
8
2. Pericardial effusion
• Accumulation of fluid in the pericardial cavity
– May be transudate (protein-poor fluid)
– May be exudate (protein rich fluid)
– May be blood
9
10
3. Constrictive (chronic) pericarditis
• Years ago, synonymous with T.B.
• Today, usually idiopathic, or associated
with radiation exposures, rheumatoid
arthritis, uremia, or coronary bypass graft
(surgical procedure performed to relieve angina and reduce the risk
of death from coronary artery disease)
11
Symptoms and Signs
•
•
•
•
Exercise intolerance
Dsypnea on exertion (shortness of breath)
Fatigue
Anorexia (eating disorder)
12
Clinical manifestations
•
•
•
•
•
Weight loss
Edema and ascites
Distention of jugular vein (Kussmaul sign)
Enlargement of the liver and/or spleen
ECG shows inverted T wave and atrial
fibrillation
• Can be seen on imaging
13
Treatment
• Drugs and diet
– Digitalis
– Diuretics
– Sodium restriction
• Surgery to remove restrictive pericardium
14
Disorders of Heart Muscles
Cardiomyopathies
15
Cardiomyopathies
• Disorders of the heart muscle
• Most cases idiopathic
• Many due to ischemic heart disease and
hypertension.
• Three categories:
A. Dilated ( formerly, congestive)
B. Hypertrophic
C. Restrictive
• Heart loses effectiveness as a pump
16
A. Dilated cardiomyopathy
• It is characterized by dilation and impaired contraction of
one or both ventricles
• Most common form of cardiomyopathy accounting for one
third of cases.
17
B. Hypertrophic Cardiomyopathy
• Genetic disease in which the heart muscle thickens abnormally
• The thickened heart muscle can interfere with the heart's electrical
system, increasing the risk for life-threatening abnormal heartbeats
(arrhythmias) and, rarely, sudden death.
18
C. Restrictive cardiomyopathy
• Portions of the heart wall become rigid and lose
their flexibility. so it's harder for the ventricles to fill
with blood between heartbeats.
• Thickening often occurs due to abnormal tissue
invading the heart muscle (Amyloid) and in elderly.
19
Disorders of the Endocardium
20
1. Valvular dysfunction
• Endocardial disorders damage heart valves
• Changes can lead to :
– Valvular Stenosis = too narrow
– Valvular Regurgitation = too leaky
(or insufficiency or incompetence)
21
22
• Valves that are most often affected are the
mitral and aortic valves,
• but in I.V. drug users and in athletes that
inject performance enhancing drugs, > 50 %
involve only the tricuspid valve.
• Heart Murmur – sound caused by turbulent
blood flow through damaged valves.
23
Both types of valve disorders:
• Cause increased cardiac work, and
increased volumes and pressures in the
chambers.
• This leads to chamber dilation and
hypertrophy.
• Chamber dilation and myocardial
hypertrophy are compensatory
mechanisms to increase the pumping
capability of the heart.
• Eventually, the heart fails from overwork
24
2. Aortic Stenosis
• Three common causes:
– Rheumatic heart disease
-Streptococcus infection –
damage by bacteria and
auto-immune response
– Congenital malformation
– Degeneration resulting
from calcification
25
3. Mitral Stenosis
• Most common of all valve disorders
• result of rheumatic fever or bacterial endocarditis
• During healing the orifice narrows, the valves become fibrous and
fused, and chordae tendineae become shortened
• Get decreased flow from LA to LV during filling
• Results in hypertrophy of LA
26
4. Aortic Regurgitation (Aortic insufficiency)
• Heart condition in which the valve between the left ventricle (lower left
heart chamber) and the aorta (the major blood vessel leaving the heart)
malfunctions.
• This valve defect allows the pumped out blood to leak back into the heart.
• As a result, the left ventricle must work harder to pump more blood than
normal.
27
5. Mitral Regurgitation
Mitral regurgitation (MR), mitral insufficiency or mitral
incompetence is a disorder of the heart in which the mitral
valve does not close properly when the heart pumps out
blood.
It is the abnormal leaking of blood from the left ventricle,
through the mitral valve, and into the left atrium, when the
left ventricle contracts, i.e. there is regurgitation of blood
back into the left atrium.
Management
•
•
•
•
Echocardiography for diagnosis
Related to degree of regurgitation
Antibiotics before invasive procedures
 blockers to relieve syncope, severe
chest pain, or palpitations
• Avoid hypovolemia
• Surgical repair
29
General Treatment for Valve disorders
• Antibiotics for Strep
• Anti-inflammatories for autoimmune disorder
• Analgesics for pain
• Restrict physical activity
• Valve replacement surgery
30
Heart Failure
• The heart as a pump is insufficient to meet
the metabolic requirements of tissues.
• Can be due to:
– dysfunction of the left ventricle
– dysfunction of the right ventricle
– or due to inadequate perfusion despite
normal or elevated cardiac output
31
Classification of Heart Failure
• Acute –develops quickly
» 65% survival rate
• Chronic – conditions gradually increase
demands on the heart; when the heart and
circulatory system can no longer adapt the
result is heart failure
– Can lead to acute failure with excessive
cardiac demand
32
Four broad consequences of
heart failure
•
•
•
•
Congestion – blood backs up
Activation of circulatory compensations
Cardiac output declines
Death
33
Types of Heart Failure
High output vs. Low output
• High output
– Anemia
– Septicemia
– Hyperthroidism (thyrotoxicosis)
– Beriberi (Vitamin B1 or thiamine difficiency)
• Low output
– Decreased pumping ability and cardiac output
34
Right-sided vs. Left sided Heart Failure
• Right-sided HF
– Most common cause is left heart failure
– Can occur independently in primary lung
disease conditions
• COPD, ARDS, cystic fibrosis
• Cor pulmonale (pulmonary heart disease is
enlargement of the RV as a response to increased
resistance or high blood pressure in the lungs)
• Left-sided HF
– Decreased output to body
– Blood backs up
35
Systolic vs. Diastolic HF
• Systolic – decreased contraction leads to
decreased output and poor perfusion of
tissues
• Diastolic heart failure or diastolic
dysfunction refers to decline in
performance of one or both ventricles of
the heart during the Time phase of
Diastole
36