Angina pectoris is a clinical syndrome normally best characterized by episodes
or paroxysms of pressure and pain in the anterior part of the chest. The primary cause of this condition is the insufficient coronary blood flow which results in the decreased oxygen supply when there is increased myocardial demand for oxygen in response or physical exertion or emotional stress.
The severity of angina pectoris is primarily based on the precipitating activity and its effects on activities of daily living. It is generally caused by atherosclerotic disease and almost invariably angina is associated with a significant obstruction of a major coronary artery. Normally, the myocardium extracts a huge amount of oxygen from the coronary circulation (circulation that perfuse oxygen rich blood to the cardiac muscles) to meet its continuous demands.
Pathophysiology of angina pectoris
In angina pectoris, there is an increased in demand and flow through the coronary arteries is also proportionally increased to meet such demand. In other words the need for oxygen substantially exceeds the existing supply especially when there is a blockage in one of the branching coronary arteries wherein blood flow cannot be increased, pressure builds up and ischemia results. There are several factors that can precipitate an attack which are associated factors with the following:
- Physical exertion which can precipitate an attack by increasing myocardial demand.
- Exposure to cold which can cause vasoconstriction and elevated blood pressure with increased oxygen demand.
- Eating a heavy meal, which increases the blood flow to the mesenteric area of the lower gastrointestinal tract thereby reducing the blood supply available to the coronary circulation.
- Any stress or emotion-provoking situation causes the release of catecholamines which increases the blood pressure, heart rate and the heart’s workload.
Clinical manifestations of angina pectoris
In angina pectoris, there is ischemia if the heart muscle produces pain or other similar symptoms, varying in severity from mild indigestion to a choking or heavy sensation in the upper chest that ranges from discomfort to agonizing pain accompanied by severe apprehension and a feeling of impending doom. The pain is often felt deep in the chest behind the sternum (retro-sternal area). Usually, the pain and discomfort are poorly localized that normally radiates to the neck, jaw, shoulders and inner aspects of the upper arms usually the left arm. A feeling of weakness or numbness in the arms, wrists and hands as well as shortness of breath, pallor, diaphoresis, dizziness or lightheadedness, nausea and vomiting may accompany the pain sensation. The important and qualifying characteristic of angina is that it subsides with rest periods and nitroglycerin.
General medical management of angina pectoris
The general objectives in managing individuals with angina pectoris are to decrease the oxygen demand of the myocardium and to increase
the oxygen supply to the coronary circulation. Medically, those objectives are met through pharmacologic therapy and control of the risk factors. Alternatively, severely reperfusion procedures (which may be invasive and surgical in nature) may be initiated to restore adequate blood supply to the myocardium. Moreover, oxygen therapy is the first and easily accessible treatment modality for patients experiencing angina pectoris in an attempt to increase the amount of oxygen delivered to the myocardium and to decrease pain sensation brought about by ischemia.