The following points highlight the four major types of heart diseases. The types are: 1. Cardiovascular Disease 2. Ischaemic (Coronary) Heart Disease 3. Angina Pectoris 4. Myocardial Infarction.
Type # 1. Cardiovascular Disease:
A. Chest pain:
a. Chest pain is a common presentation of cardiac disease, but it can also signify disease of the lungs and the gastrointestinal system.
b. Cardiac pain is centrally located in the chest on account of the derivation of the nerve supply to the heart and mediastinum. Pain is only experienced at a peripheral site in the chest.
c. This pain is dull, constricting or heavy. It may not be appreciated as pain but as discomfort, and the constricting sensation can be described as breathlessness.
d. The pain is very sudden in onset (seconds). Myocardial infarction pain takes several minutes or even longer to develop.
e. The severe pain of myocardial infarction is accompanied by sweating, nausea and vomiting.
f. Angina is a choking or constricting chest pain which comes with exertion and is relieved by rest. The pain becomes worse by large meals or a cold wind. It is relieved by nitrates.
g. Myocardial infarction is more severe and does not respond to nitrates, vomiting is common.
h. Oesophageal pain is precipitated by exercise and may be relieved by nitrates.
B. Heart failure:
a. Heart failure may be diagnosed whenever a patient with significant heart disease develops the symptoms of low cardiac output, pulmonary congestion or systemic venous congestion.
b. Heart failure is frequently due to coronary artery disease and tends to affect elderly subjects.
c. Heart failure may develop suddenly, as in myocardial infarction.
d. A low cardiac output causes fatigue. The peripheries are cold and the blood pressure is low, poor renal perfusion leads to uremia.
e. Chronic heart failure is sometimes associated with marked weight loss caused by impaired absorption due to gastrointestinal congestion.
f. In advanced heart failure, there occurs hypokalemia, hyponatremia, impaired liver function and thromboembolism. Patients with heart failure should be advised to avoid a high dietary salt intake, excess alcohol, salt or fluid retaining drugs.
g. Diuretics are usually the first line of treatment in this case.
Other Manifestations of Cardiovascular Disease:
A. Oedema:
1. This is a symptom of chronic heart failure and is due to excessive salt and water retention.
2. It usually affects the ankles, legs, thighs and lower abdomen.
3. Oedema of nephrotic syndrome tends to be more severe and often affects the face and arms.
B. Palpitations:
a. This is an abnormal subjective awareness of the heart-beat.
b. Palpitation with a regular rhythm and a normal heart rate may be due to sudden vasodilatation.
C. Syncope:
a. This is a loss of consciousness resulting from an inadequate blood supply to the
brain. This is due to sudden vasodilatation.
b. Exertional syncope may occur under conditions of aortic stenosis.
Type # 2. Ischaemic (Coronary) Heart Disease:
It is the commonest form of heart disease and the most important cause of premature death in the developed world.
The following factors are responsible for coronary heart disease:
a. Age and male sex:
These are the risk factors which cannot be corrected. Hormone replacement therapy reduces the disease.
b. Smoking:
Tobacco is the most important cause of coronary disease. The risk is highest in young people and becomes lower within six months of quitting.
c. Hypertension:
The coronary artery disease increases as blood pressure rises. Antihypertensive drugs can reduce the disease.
d. Hypercholesterolemia:
Patients with hyperlipidemia have a high incidence of premature coronary disease. The excess risk is closely related to the plasma concentration of LDL: cholesterol.
e. Diabetes mellitus:
Insulin resistance is associated with obesity and physical inactivity and is also a potent risk factor for coronary heart disease.
f. Hemostatic factors:
High levels of fibrinogen and factor VII are associated with an increased risk of myocardial infarction (coronary thrombosis).
g. Physical activity:
Regular exercise (walking, cycling or swimming) has a protective effect which has the ability to increase HDL: cholesterol, lower blood pressure, reduce blood clotting.
h. Alcohol:
A moderate intake of alcohol (2 to 4 units a day) offers some protection from coronary disease. Heavy drinking is associated with hypertension and an excess of cardiac events.
i. Mental stress:
Stress can produce the symptoms of heart disease.
j. Other dietary factors:
Diets deficient in polyunsaturated fatty acids are associated with an increased risk of coronary disease. Decreased levels of Vitamin C, Vitamin E and other antioxidants may promote the production of oxidized LDL.
Prevention for Coronary Disease:
a. Smoking is prohibited.
b. Regular exercise is a must.
c. Ideal body weight must be maintained.
d. Mixed diet with fruits and vegetables as well as meat and dairy products must be taken as food.
e. Fats containing polyunsaturated fatty acids must be taken.
Type # 3. Angina Pectoris:
This is described as discomfort due to transient myocardial ischaemia and forms a clinical syndrome rather than a disease. It may occur due to an imbalance between myocardial oxygen supply and demand.
Clinical Symptoms:
a. Stable angina is characterised by left-sided or central chest pain.
b. Most patients describe a sense of oppression or tightness in the chest — “like a band round the chest”.
c. Many patients report a “choking” sensation. Breathlessness is sometimes a prominent feature.
d. The pain may radiate to the neck and is often accompanied by discomfort in the arms.
e. Symptoms become worse after a heavy meal, in the cold, in walking uphill, into a strong wind and in lying flat.
f. Care must be taken for important risk factors like nicotine stains, hypertension, hyperlipidemia, diabetes mellitus, myxoedema, contributory disease like obesity, anemia, thyrotoxicosis.
Advice to patients with angina:
i. Smoking is strictly prohibited.
ii. Ideal body weight must be maintained.
iii. Regular exercise should be taken.
iv. Severe unaccustomed exertion, vigorous exercise after a heavy meal or in very cold weather must be avoided.
v. The anti-anginal drugs, e.g., nitrates, beta-adrenoceptor antagonists (beta-blockers) and calcium antagonists must be taken.
Type # 4. Myocardial Infarction:
It occurs due to the formation of thrombus at the site of rupture of an atheromatus plaque in a coronary artery. The thrombus often undergoes spontaneous lysis by the next few days.
Clinical Symptoms:
a. Pain is the principal symptom; but breathlessness, vomiting and collapse or syncope are common features.
b. The pain is more severe and lasts longer. It is often described as a tightness, heaviness or constriction in the chest.
c. Most patients are breathless. Syncope occurs due to profound hypotension.
d. Vomiting and sinus bradycardia often occur due to vagal stimulation and are particularly common in patients with this disease.
e. Some myocardial infarcts are un-recognised. These painless myocardial infarcts are common in elderly and diabetic patients.
f. Sudden death from ventricular fibrillation may occur immediately and many deaths occur within the first hour. If the patient survives this most critical stage, the dangerous state remains, but diminishes as each hour goes by.
g. The development of cardiac failure shows the extent of myocardial damage and is the major cause of death in those who survive the first few hours of infarction.
h. There are signs of tissue damage causing fever, leucocytosis, high ESR.
Investigations:
a. The ECG is usually a sensitive and specific way of confirming the diagnosis.
b. The plasma enzymes creatine kinase (CK), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) should be estimated. CK starts to rise at 4-6 hours, peaks at about 12 hours and falls to normal within 48-72 hours. AST starts to rise about 12 hours after infarction and reaches a peak on the first or second day, returning to normal within 3 or 4 days.
LDH starts to rise after 12 hours, reaches a peak after 2 or 3 days and may remain elevated for a week or more. Measurements of LDH are appropriate when a patient presents several days after a possible infarct. Unfortunately, LDH is highly concentrated in red cells and abnormal results may be obtained due to very mild hemolysis.
c. The ESR becomes raised and may remain so for several days.
Early management of acute myocardial infarction:
a. Bed rest is most essential.
b. Oral aspirin is needed.
c. High flow oxygen should be administered.
d. Beta adrenoceptor antagonist should be considered.
e. I.V. analgesia with opiates should be arranged.
Risk factor modification:
a. Giving up smoking is the most effective decision for the future not to face coronary attack.
b. Lipid lowering therapy is ideal to reduce the risk of attack.
c. Maintaining an ideal body weight, taking regular exercise, having good control of hypertension and diabetes may improve the long-term outlook.
Prognosis:
a. Death occurs within a few minutes without medical care in about one fourth of all cases of myocardial infarction.
b. Half the deaths occur within two hours and three quarters within 24 hours of the onset of symptoms of myocardial infarction.
c. The un-favourable features in this case include poor left ventricular functions and heart block.
d. Old age, stress and social isolation are the main cause for the enhancement of this disease.
e. Among the patients who survive an acute attack, more than 80 per cent live for a further year, about 75 per cent for 5 years, 50 per cent for 10 years and 25 per cent for 20 years.