Acute coronary syndrome is a term that describes a range of conditions related to sudden, reduced blood flow to the heart. These conditions include a heart attack and unstable angina.
A heart attack happens when cell death damages or destroys heart tissue. A heart attack also is known as a myocardial infarction.
Unstable angina occurs when blood flow to the heart decreases. It’s not severe enough to cause cell death or a heart attack. But the reduced blood flow may increase your risk of a heart attack.
Acute coronary syndrome often causes severe chest pain or discomfort. It is a medical emergency that needs a diagnosis and care right away. The goals of treatment include improving blood flow, treating complications and preventing future problems.
Symptoms
The symptoms of acute coronary syndrome usually begin suddenly. They include:
- Chest pain or discomfort. This is often described as aching, pressure, tightness or burning. Chest pain also is called angina.
- Pain that starts in the chest and spreads to other parts of the body. These areas include the shoulders, arms, upper belly area, back, neck or jaw.
- Nausea or vomiting.
- Indigestion.
- Shortness of breath, also called dyspnea.
- Sudden, heavy sweating.
- Racing heartbeat.
- Feeling lightheaded or dizzy.
- Fainting.
■ Essentials of Diagnosis
• Classified as ST-segment elevation (Q wave) myocardial infarction
(MI), non–ST-segment elevation (non-Q wave) MI, or unstable angina
• Prolonged (> 30 minutes) chest pain, associated with shortness of
breath, nausea, left arm or neck pain, and diaphoresis; can be
painless in diabetics
• S4 common; S3, mitral insufficiency on occasion
• Cardiogenic shock, ventricular arrhythmias may complicate
• Unrelenting chest pain may mean ongoing jeopardized myocardium
Causes
Acute coronary syndrome usually results from the buildup of fatty deposits on the walls of blood vessels that deliver blood, oxygen and nutrients to heart muscles. Fatty deposits also are called plaque. The blood vessels that supply the heart also are known as coronary arteries.
When a fatty deposit ruptures or splits, a blood clot forms. This clot blocks the flow of blood to heart muscles.
When the supply of oxygen to cells is too low, cells in the heart muscles can die. The death of cells results in damage to muscle tissues. This is called a heart attack.
Even when there is no cell death, the drop in oxygen still results in heart muscles that don’t work the way they should. This change may be short-lived or permanent. When acute coronary syndrome doesn’t result in cell death, it is called unstable angina.
■ Differential Diagnosis
• Stable angina; aortic dissection; pulmonary emboli
• Tietze’s syndrome (costochondritis)
• Cervical or thoracic radiculopathy, including pre-eruptive zoster
• Esophageal spasm or reflux; cholecystitis
• Pericarditis; myocarditis; Takotsubo’s (stress-induced) cardiomyopathy
• Pneumococcal pneumonia; pneumothorax
■ Treatment
• Monitoring, oxygen, aspirin, oral beta-blockers, and heparin if not
contraindicated; consider clopidogrel
• Reperfusion by thrombolysis early or percutaneous coronary intervention (PCI) in selected patients with either ST-segment elevation or new left bundle-branch block on ECG
• Glycoprotein IIb/IIIa inhibitors considered for ST-segment elevation MI in patients undergoing PCI
• Nitroglycerin and morphine for recurrent ischemic pain; also
useful for relieving pulmonary congestion, decreasing sympathetic tone, and reducing blood pressure
• Angiotensin-converting enzyme (ACE) inhibitors, angiotensin II
receptor blockers, and aldosterone blockers such as eplerenone
improve ventricular remodeling after infarcts