Angina Pectoris : Definition
Angina pectoris is a term that describes chest pain caused by myocardial ischemia - a condition in which the amount of oxygen getting to the heart muscle is insufficient. It usually occurs on exertion and is relieved by rest. Angina generally is a symptom ofcoronary artery disease. In most severe cases, it may occur with minimal effort or at rest.
Causes
The two main causes of angina are coronary artery spasm, and atherosclerotic plaque buildup which causes critical blockage of the coronary artery.
The risk factors include:
• smoking
• sedentary lifestyle
• high blood pressure, or hypertension
• high blood fats or cholesterol
• hypercholesterolemia
• diabetes
• family history of premature ischemic heart disease
Men are at higher risk than women.
Treatment
In most instances, drugs are recommended for the treatment of angina before surgery is considered. The major classes of drugs used to treat angina include the following:
Nitrates. These come in several forms: nitroglycerine tablets to be slipped under the tongue during or in anticipation of an attack; ointment to be absorbed through the skin; long-acting medicated skin discs; or long-acting tablets. The latter three forms are used mostly to prevent rather than relieve attacks. The nitrates work by reducing the oxygen requirements of the heart muscle.
Beta-blocking Drugs. These agents act by blocking the effect of the sympathetic nervous system on the heart, slowing heart rate, decreasing blood pressure, and thereby, reducing the oxygen demand of the heart. Recent studies have found that these drugs also can reduce the chances of dying or suffering a recurrent heart attack if they are started shortly after suffering a heart attack and continued for two years.
Calcium-channel Blocking Drugs. These drugs are prescribed to treat angina that is thought to be caused by coronary artery spasm. They can also be effective for stable angina associated with exercise. All muscles need varying amounts of calcium in order to contract. By reducing the amount of calcium that enters the muscle cells in the coronary artery walls, the spasms can be prevented. Some calcium-channel blocking drugs also decrease the workload of the heart and some lower the heart rate as well.
Arrhythmia : DEFINITION
Arrhythmia is defined as loss of cardiac rhythm, especially irregularity of heart-beat and is an abnormal cardiac rhythm, usually involving the change in rate or regularity and is monitored by using Electrocardiograph (ECG).
PATHOPHYSIOLOGY
The blood pushed from ventricles in a controlled sequence of muscle contraction. In cardiac arrhythmia, there will be disturbed in the sequence and in electrical conductivity.
Arrhythmias are classified in to differentkinds depending upon the disorders of impulse generation and includes,
Premature contraction - Common arrhythmia, which affect large number of people. Caffeine and stress increases the occurrence of premature beats.
Tachycardia - An abnormally fast heart beats (more than 100beats/min) ,this can also lead to insufficient blood circulation.
Bradycardia- An abnormally fast heart beats (more than 100beats/min). This can also lead to insufficient blood circulation.
Atrial fibrillation- A rapid, irregular heart rhythm caused by abnormal electrical impulses that begins in the upper chambers of the heart.In atrial fibrillation the heart rate is even higher i.e. 500 beats/min.
Atrial flutter - In atrial flutter the heart rate is 250-350 beats/min, associated with tachycardia.Commonly seen in hyperthyroidism and heart failure.
Ventricular fibrillation - Life threatening condition in which the heartquivers very rapidly about 350times/min or more.This leads to rapidly fatal if not reversed by defibrillation.