disorders of myocardial blood supply
DESCRIPTION
disorders of myocardial blood supplyTRANSCRIPT
Department of Nursing Sciences,
Faculty of Medicine,
Ahmadu Bello University, Zaria.
Topic;
Disorders of myocardial blood supplyBy;
ABDULLAHI Abbas
(student 400level)
OUTLINE
a) Blood supply to the heart
b) Risk factors of coronary artery diseases
c) Coronary artery diseases(C.A.D)
d) Myocardial infarction
e) Angina pectoris
Blood supply to the heart
Coronary Circulation
Coronary arteries;
Right coronary artery; originates from the right aortic
sinus, descends along the anterior side of the heart towards
the right along the inferior border of the right auricle, then
wraps posteriorly around the heart; gives rise to the
following branches:
SA nodal artery- usually branches from the right coronary
artery; supplies the SA node
Right marginal branch- supplies the right border of the
heart
AV nodal artery- supplies AV node
Posterior interventricular artery- supplies both ventricles
and the interventricular septum from the posterior side of
the heart
Left coronary artery; originates from the left aortic sinus,
descends along the anterior side of the heart towards the
left, courses between the pulmonary trunk and the left
auricle then bifurcates into the following branches:
Anterior interventricular branch (LAD)- descends along the
anterior surface towards the apex supplying the left
ventricle and interventricular septum
Circumflex branch- wraps posteriorly around the heart in
the coronary sulcus, gives rise to the left marginal artery
which supplies the left border of the heart.
Cardiac veins
Coronary sinus; courses along the posterior side of the
heart in the coronary sulcus; drains blood from the following
cardiac veins to the right atrium;
Great cardiac vein (anterior interventricular vein)-
ascends from the apex along the anterior side of the heart
in the anterior interventricular sulcus.
Middle cardiac vein (posterior interventricular vein)-
ascends from the apex along the posterior side of the
heart in the posterior interventricular sulcus.
Small cardiac vein- (right marginal vein)- courses with the
right marginal artery, wraps around the right border of the
heart in the coronary sulcus.
Anterior veins- originate on the anterior surface of the
right ventricle, course over the coronary sulcus to drain
directly into the right atrium.
CORONARY ARTERY DISEASE(C.A.D)
Is an abnormal accumulation of lipid or fatty substances
and fibrous tissues in the lining of the coronary arterial
vessels walls which lead to blockage and narrowing of the
vessels in a way that reduces blood flow to the
myocardium (muscles of the heart).
Risk factors of coronary artery
diseases
Age and gender
Family history and genetic
Diabetes
Hypertension
Tobacco use
Sedentary lifestyle
hyperlipidemia
Obesity
Stress
Poor diet etc.
Clinical manifestation
Asymptomatic.
Chest pain (angina) because of decreased blood flow to
heart muscle and/or increase in myocardial oxygen
demand resulting from stress. Chest pain lasts between 3
to 5 minutes.
Chest pain can occur when the patient is resting.
Pain may radiate to the arms, back, and jaw.
Chest pain occurs after exertion, excitement, or when the
patient is exposed to cold temperatures because there is
an increase in blood flow throughout the body, raising the
rate.
Some times shortness of breath(dyspnea)
Fatigue
Anxiety
restlessness
pathophysiology
Cholesterol, calcium and other elements
Deposited on the coronary artery wall
Narrowing of the artery and reduction of blood flow
Impedes blood supply to the heart muscle
Deposits start as fatty streaks and eventually develop into plaque
Diagnosis
History taking
Chest x-ray
Electrocardiograph
Cardiopulmonary angiography
Blood chemistry
Management
Treatment consists of;
Risk factor modification,
Life style changes,
Medications and,
revascularization.
Weight loss.
Diet change: lower sodium, lower cholesterol and fat,
decreased calorie intake, increased dietary fiber.
Administer low doses of aspirin.
Administer beta-adrenergic blockers to reduce workload
of heart: metroprolol, propranolol, nadolol.
Administer calcium channel blockers to reduce heart rate,
blood pressure,and muscle contractility; helps with
coronary vasodilation; slows AV node conduction.
Administer nitrate if patient has symptomatic chest pains
to reduce discomfort and enhance blood flow to
myocardium.
Platelet inhibitors:dipyridamole clopidogrel and
ticlopidine.
Administer HMG CoA reductase inhibitors (statins)—lowers
cholesterol:
a) lovastatin
b) simvastatin
c) atorvastatin
d) fluvastatin
e) pravastatin
f) rosuvastatin
Fibric acid derivatives reduce synthesis and increase
breakdown of VLDL particles: gemfibrozil.
Nursing diagnosis
Acute pain
Activity intolerance
Impaired gas exchange
Angina Pectoris
A narrowing of blood vessels to the coronary artery,
secondary to arteriosclerosis,
results in inadequate blood flow through blood vessels of
the heart muscle, causing chest pain.
Types of angina
Stable angina pectoris; pain is relieved by rest or nitrates
and symptoms are consistent.
Unstable angina pectoris; pain occurs at rest; is of new
onset; is of increasing intensity, force, or duration; isn't
relieved by rest; and is slow to subside in response to
nitroglycerin.
Prinzmetal angina pectoris; usually occurs at rest or with
minimal formal exercise or exertion; often occurs at
night.
causes
An episode of angina is typically precipitated by physical
activity, excitement, or emotional stress.also due to
diseases such as;
Coronary atherosclerosis
Anaemia
Polycythaemia
Aortic stenosis
Extreme cold
Smoking
pathophysiology
.• Narrowing of coronary artery
.• Inadequate blood flow through the heart
‘
• Reduced myocardial oxygenation that leads to discrepancy btw the oxygen and energy expended
• Causing chest pain, which also radiate to left or both shoulders, arms, neck and jaws
Clinical manifestation
Chest pain lasting 3 to 5 minutes—not all patients get
substernal pain; it may
be described as pressure, heaviness, squeezing, or
tightness. Use the patient’s
words.
Can occur at rest or after exertion, excitement, or
exposure to cold—due to
increased oxygen demands or vasospasm.
Usually relieved by rest—a chance to re-establish oxygen
needs.
Pain may radiate to other parts of the body such as the
jaw, back, or arms—
angina pain is not always felt in the chest. Ask if the
patient has had similar
pain in the past.
Sweating (diaphoresis)—increased work of body to meet
basic physiologic
needs; anxiety.
• Tachycardia—heart pumping faster trying to meet
oxygen needs as anxiety
increases.
• Difficulty breathing, shortness of breath (dyspnea)—
increased heart rate
increases respiratory rate and increases oxygenation.
• Anxiety—not getting enough oxygen to heart muscle, the
patient becomes
nervous.
diagnosis
History taking
Electrocardiography
Echocardiograph
Coronary angiography
Radionuclide imagine
Basic screening;
a) Fasting blood glucose
b) Serum lipids including high
density lipoproteins (HDL)
and triglycerides
c) Full blood count
d) Blood urea and electrolytes
e) Serum urates
management
The goal of treatment is to deliver sufficient oxygen to
the heart muscle to meet its need, 2 to 4 liters of oxygen.
Administer beta-adrenergic blocker e.g. propranolol,
nadolol, atenolol, metoprolol.
Administer nitrates—aids in getting oxygenated blood to
heart muscle.
a) Nitroglycerin—sublingual tablets or spray; timed-release
tablets.
b) Topical nitroglycerin—paste or timed-released patch.
Aspirin for antiplatelet effect.
Analgesic
Nursing diagnoses
Anxiety
Decreased cardiac output
Acute pain
Myocardial Infarction commonly known as heart attack
Is when blood supply to the myocardium is interrupted for a
prolonged time due to the blockage of coronary arteries
resulting in insufficient oxygen reaching cardiac
muscle,causing cardiac muscles to die (necrosis).
causes
Coronary atherosclerosis
Coronary thrombosis
Coronary embolism
Hypovolemic shock
pathophysiology
Blockage of the coronary artery
Resulting to insufficient oxygen supply
Leading to death of the cardiac muscle(necrosis)
Clinical manifestation
Chest pain that is unrelieved by rest or nitroglycerin, unlike
angina
Pain that radiates to arms, jaw, back and/or neck
Shortness of breath, especially in the elderly or women
Nausea or vomiting possible
Maybe asymptomatic, known as a silent MI, which is more
common in diabetic patients
Heart rate >100 (tachycardia) because of sympathetic
stimulation, pain, or low cardiac output
Variable blood pressure
Anxiety
Restlessness
Feeling of impending doom
Pale, cool, clammy skin; sweating (diaphoresis)
Sudden death due to arrhythmia usually occurs within first
hour
diagnosis
History taking
Electrocardiography(ECG)
Erythrocyte sedimentation rate(ESR)
Echocardiography
Radionuclide imaging
Cardiac enzyme analysis; creatinine phosphokinase, lactic
dehydrogenase, and aspartate aminotransferase.
management Treatment is focused on reversing and preventing further
damage to the myocardium.
Early intervention is needed to have the best possible
outcome
Administer oxygen, aspirin.
Administer antiarrhythmics because arrhythmias are
common as are conduction disturbances.
a) Amiodarone.
b) Lidocaine.
c) Procainamide.
Electrical cardioversion for unstable ventricular
tachycardia. An initial shock is administered to the heart
to re-establish sinus rhythm.
Administer antihypertensive to keep blood pressure low
e.g Hydralazine.
Percutaneous revascularization
Administer thrombolytic therapy within 3 to 12 hours of
onset because it can re-establish blood flow in an
occluded artery, reduce mortality, and halt the size of the
infarction.
a) Alteplase.
b) Streptokinase.
c) Anistreplase.
d) Reteplase.
Heparin following thrombolytic therapy.
Administer calcium channel blockers as they appear to
prevent reinfarction and ischemia, only in non–Q-wave
infarctions. e.g. Verapamil, Diltiazem.
Administer beta-adrenergic blockers because they reduce
the duration of ischemic pain and the incidence of
ventricular fibrillation; decreases mortality. Propranolol.
E.g. Nadolol, Metroprolol.
Administer analgesics to relieve pain, reduce pulmonary
congestion, and decrease myocardial oxygen
consumption.e.g. Morphine.
Administer nitrates to reduce ischemic pain by dilation of
blood vessels; helps to lower BP.e.g Nitroglycerin.
Place patient on bed rest in CCU.
No bathroom privileges. Bedside commode only.
Low-fat, low-caloric, low-cholesterol diet.
Nursing diagnoses
Ineffective tissue perfusion
Decreased cardiac output
General complications of myocardial
blood supply disorders
Myocardial ischemia
Pericarditis
Cardiogenic shock
Depression etc.
THANKS FOR READING!
ABDULLAHI Abbas