Initial diagnosis of acute coronary syndrome is almost entirely based on history, risk factors, and, to a lesser extent, ECG. The symptoms are due to myocardial ischemia, which has an underlying cause of an imbalance between supply and demand for myocardial oxygen.
History
• Typically, angina is a symptom of myocardial ischemia that appears in circumstances of increased oxygen demand. It usually is described as a sensation of chest pressure or heaviness that is reproduced by activities or conditions that increase myocardial oxygen demand.
• Not all patients experience chest pain. Some present with only neck, jaw, ear, arm, or epigastric discomfort.
• Other symptoms, such as shortness of breath or severe weakness, may represent anginal equivalent symptoms.
• A patient may present to the ED because of a change in pattern or severity of symptoms. A new case of angina is more difficult to diagnose because symptoms are often vague and similar to those caused by other conditions (eg, indigestion, anxiety).
• Patients may have no pain and may only complain of episodic shortness of breath, weakness, lightheadedness.
Patients may complain of the following:
• Palpitations
• Pain, which is usually described as pressure, squeezing, or a burning sensation across the precordium and may radiate to neck, shoulder, jaw, back, upper abdomen, or either arm
• Exertional dyspnea that resolves with pain or rest
• Diaphoresis from sympathetic discharge
• Nausea from vagal stimulation
• Decreased exercise tolerance
• Patients with diabetes and elderly patients are more likely to have atypical presentations and offer only vague complaints, such as weakness, lightheadedness, and nausea.ess, diaphoresis, or nausea and vomiting
Risk Factors
• Male gender
• Diabetes mellitus (DM)
• Smoking history
• Hypertension
• Increased age
• Hypercholesterolemia
• Hyperlipidemia
• Prior cerebrovascular accident (CVA) - These patients constitute 7.5% of patients with ACS and have high-risk features (Hasdai, 2003).
• Inherited metabolic disorders (Wilken, 2003)
• Methamphetamine use (Turnipseed, 2003)
• Occupational stress (Panagiotakos, 2003)
• Connective tissue disease (Soejima, 2004)
ECG
• Transient ST segment elevations (fixed changes suggest acute MI): In patients with elevated ST segments, consider LV aneurysm, pericarditis, Prinzmetal angina, early repolarization, and Wolff-Parkinson-White syndrome as possible diagnoses.
• Dynamic T-wave changes, either inversions, normalizations, or hyperacute changes: In patients with deep T-wave inversions, consider also CNS events or drug therapy with tricyclic antidepressants or phenothiazines.
• ST depressions that may be junctional, downsloping, or horizontal
• Diagnostic sensitivity may be increased by performing right-sided leads (V4R), posterior leads (V8, V9), and serial recordings
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