Pain may arise in a muscle when it is made to contract repeatedly or to remain contracted in a sustained state, while its arterial blood supply is diminished below physiological limits. When this situation occurs in the heart, which is primarily a muscle, we apply the term angina pectoris, which means "pain of the chest". Other conditions may cause chest pain in the same areas and must be differentiated from true angina (of cardiac origin). This is seldom difficult for the physician.
Angina pectoris is most commonly seen in patients past 40 years of age, and men outnumber women with this affliction. It typically occurs as a severe, sharp, oppressive, squeezing, or knifelike stabbing pain in the front (anterior) of the chest along and under the sternum. It usually comes after the person has exerted his heart and exceeded the physiological limit of the blood supply to the heart muscle. This exertion threshold varies among individuals, depending upon the severity of the vascular disease that causes the pain. Some patients will experience an anginal "attack" after running or ascending stairs. Others will experience excruciating pain even while slowly walking. Most sufferers are painfree when they are resting; hence, mild or moderate shooting or continuous pain occurring at rest and not aggravated by effort is probably not angina. When angina occurs, relief usually comes with rest. The patient instinctively stops his activity. The pain lasts variably up to half an hour, usually much less. The attack causes no damage, if exertion is ceased. The patient must either live within the limitation of the blood supply of his heart muscle, or employ vasodilator drugs. The diminished blood supply is caused usually by atherosclerosis, with thickening of the walls of the arteries arid arterioles and resultant narrowing of their lumen, or "bore". These blood vessels carry less blood than in health and their capacity in terms of flow is exceeded by the needs of the working myocardium during periods of greater activity.
The prognosis in angina pectoris is extremely variable, but any patient, whether his symptoms are mild or severe, may die suddenly or develop a crippling coronary thrombosis (heart infarct). It is therefore extremely important that these patients be advised as to their mariner of living, and a member of the family should be taken into the physician's confidence and informed of the possibilities of sudden death. Many patients, by living within the limits of their cardiac reserve, may live for many years after the onset of angina.
The treatment of angina may be divided into two phases; the treatment of individual attacks, and the prevention (or at least a diminution in the number) of possible attacks. The use of nitroglycerin tablets in 1/100 or 1/200 grain (0.6 or 0.3 mg) is the treatment of choice in acute attacks. The patient should be instructed in their use. He will learn to place a tablet under the tongue at the sign of distress and to stop and rest. He may know that certain types of exertion, such as climbing a flight of stairs, can induce an attack, and that by placing a pellet under his tongue a few seconds before the ascent he can prevent the development of pain. The smallest effective dose of nitroglycerin should be used in order to avoid unpleasant side effects.
In order to prevent attacks, the patient should be advised to avoid exertion, excitement or overeating. His whole manner of living may have to be changed to permit an easygoing existence. Tobacco should be countermanded because of its vasoconstricting action.
Frequent small feedings should, as opposed to three large meals, be encouraged, and weight reduction is very important in the obese. The use of a vasodilatating drug such as ami- nophylline (3 grains, or 0.2g) is of value.
Дата добавления: 2015-06-10; просмотров: 1032;