Wednesday, February 18, 2009
Ischemic Heart Disease
Coronary Artery Disease
Coronary artery disease (CAD) is typically defined as a >50% stenosis of any epi cardial coronary artery.It is most commonly due to obstruction by atheromatous plaque.
AD is the leading cause of morbidity and mortality in Western society and caused one of every five deaths in the United States in 2002.
The morbidity associated with CAD is considerable: More than 1 million patients have a myocardial infarction (MI) annually. Many more are hospitalized for unstable angina and evaluation and treatment of stable chest pain syndromes.
About 90% of patients with CAD have prior exposure to at least one major risk factor (see Risk Factor) Blood Vessels
The manifestations of CAD include stable angina, acute coronary syndromes (ACS), congestive heart failure, sudden cardiac death, and silent ischemia.
ACS encompasses a spectrum of clinical conditions from unstable angina to ST-elevation MI.
Stable angina most often results from fixed coronary lesions that produce a mismatch of myocardial supply and demand with increasing cardiac workload.
The presence of ischemic heart disease can predispose patients to additional problems, including heart failure, cardiac arrhythmias, and sudden cardiac death.
A careful history and physical examination are usually sufficient to provide information to establish an appropriate pretest probability of coronary disease.
Characteristics of angina:
Angina is usually described as a chest discomfort or heaviness that may radiate to the neck, jaw, or arm(s) and can be further defined as follows.
1.Typical angina (definite) is (a) substernal chest discomfort with a characteristic quality and duration that is (b) precipitated by stress and (c) relieved by rest or nitroglycerin (NTG).
2.Atypical angina (probable) meets two of these characteristics.
3.Noncardiac chest pain meets one or none of these characteristics.
Grading of angina:
Grading of angina is based on the Canadian Cardiovascular Society (CCS) Classification System.
Class I: Angina occurs only with strenuous activity.
Class II: Angina occurs with moderate activity like walking more than two blocks or climbing more than one flight of stairs.
Class III: Angina occurs with mild activity like climbing a flight of stairs or walking less than two blocks.
Class IV: Angina occurs with any activity and may occur at rest.
Associated symptoms may include dyspnea, diaphoresis, nausea, vomiting, dizziness, or palpitations. The patient's complaints may also be atypical in nature, such as epigastric discomfort.