Myocardial oxygen demand can be met if there is a balance between supply and demand of oxygen. Decrease in myocardial oxygen supply could jeopardize the function of the myocardium. Coronary heart disease is caused by an imbalance between myocardial oxygen supply and demand. If the increased myocardial oxygen demand, the oxygen supply must also increase. Increased oxygen demand occurs on: tachycardia, increased myocardial contractility, hypertension, hypertrophy, and ventricular dilatation. To increase the oxygen supply in sufficient quantity should be increased coronary artery flow.
Four factors that influence the oxygen demand of the heart:
- Heart rate
- Contraction force
- Muscle mass
- Ventricular wall tension
- Narrowing of the coronary arteries (atherosclerosis), which is a common cause.
- Decreased blood flow (cardiac output).
- Increased myocardial oxygen demand
- Coronary artery spasm.
Pathogenesis
Atherosclerosis of the coronary arteries is the cause of coronary artery disease is most often found. On coronary atherosclerosis and lipid accumulation found in the fibrous tissue of the coronary artery lumen narrowing of coronary arteries.
Mechanism of atherosclerosis:
- The tunica intima containing lipid deposition occur much cholesterol.
- Arising complex atherosclerotic plaque consisting of fat, fibrous tissue, collagen, calcium, cellular debris and capillaries.
- Degenerative changes in artery walls.
- Narrowing of the coronary artery lumen.
Risk Factors of Coronary Heart Disease
Irreversible risk factors:
- Age
- Gender
- Family history / genetics
- Race
- Hyperlipidemia, hypercholesterolemia
- Hypertension
- Smoking
- Diabetes mellitus
- Obesity
- Psychological stress
- Personality type
- Less sports activities
Clinical Manifestations
- Without symptoms
- Angina pectoris
- Acute myocardial infarction
- Arrhythmias
- Heart trouble
- Sudden death
Nursing Care Plan for Coronary Heart Disease
Assessment
- Assessment: complaints of pain, disease history, risk factors.
- Physical examination: vital signs, peripheral perfusion, capillary reffil, arterial pulse, heart sounds: S3, S4, murmurs, lung sounds: ronchi, wheezing.
- Psychological response: depression, anxiety, worry.
- ECG: T inversion, ST depression.
- Laboratory: Routine blood, cardiac enzymes, lipid profile.
- Echocardiogram.
- Cardiac catheterization.
- Chest X-ray.
Nursing Diagnosis for Coronary Heart Disease
- Ineffective Tissue perfusion
- Ineffective breathing pattern
- Acute pain
- Activity intolerance
- Anxiety
Management
- The most effective management is to detect and reduce risk factors.
- Reduces cardiac oxygen demand by decreasing heart work.
- Increasing the oxygen supply of the heart.
- Coronary revascularization.
