Final answer:
Unstable angina and NSTEMI represent more severe stages of cardiac ischemia with symptoms that can occur at rest, last longer, and indicate higher risk of a heart attack. Differentiation of NSTEMI from unstable angina requires specific tests like ECG and cardiac biomarkers. Both conditions necessitate urgent medical intervention to prevent further complications.
Step-by-step explanation:
Unstable angina and non-ST elevation myocardial infarction (NSTEMI) are conditions associated with increased severity, duration, or frequency of chest pain when compared to stable angina. Unstable angina can occur during rest, last more than 15 minutes, and indicates a new change in a patient's condition, signaling a higher risk of a heart attack. NSTEMI, while similar to unstable angina in symptom presentation, can be differentiated by specific diagnostic tests such as elevated levels of cardiac biomarkers like creatine kinase MB and cardiac troponin, and changes on an electrocardiogram (ECG).
An acute myocardial infarction (MI), commonly known as a heart attack, exhibits symptoms including sudden retrosternal pain, which may radiate down the left arm, particularly in males. However, females may present differently, which historically led to misdiagnoses. Diagnosing an MI requires careful differential diagnosis due to symptom overlap with other conditions.
While stable angina improves with rest or nitroglycerin, both unstable angina and NSTEMI indicate worsening coronary artery disease and demand urgent medical attention to prevent further cardiac damage or a heart attack, which can lead to serious complications, including sudden death, arrhythmias, heart failure, and cardiac arrest.