Unstable Angina Pathophysiology Definition STEMI and NSTEMI

Unstable Angina

• Patients with ischemic heart disease can be divided into two groups:

Patients with stable angina due to chronic coronary artery disease

• Patients with acute coronary syndrome Stable angina pectoris is characterized by chest pain or discomfort radiating to left or both arms, on physi­cal exertion or stress lasting for 5 to 10 minutes and relieved by rest and / or sublingual nitroglycerine.

Acute coronary syndrome may be divided into:

• AMI (Acute myocardial infarction) y UA (Unstable angina)
• AMI is STEMI ST-se ment elevation MI
• UA is NSTEMI (Non ST – Segment elevation MI)
• UA pectoris is chest pain or discomfort occurring at rest or mild exertion, lasting more than 10 minutes OR very severe pain of new onset (less than 6 weeks old) OR very severe, prolonged, frequent or crescendoain.
• UA is called NSTEMI when a patient of typical UA has elevated cardiac bio-markers i.e. evidence of myo­aralum necrosis (elevated troponins).

Definition

• unstable angina is acute ischemic discomfort without s-t segment elevation and without elevation of serum crdiac markers.

Pathophysiology

• There may be rupture of plaque over a throm­bus or atheroma resulting in occlusion of coro­nary artery. In UA there are white thrombi which are – platelet rich as compared to red thrombi (loose cells) in AMI.
• There may be coronary spasm as in Prinzmetal’s angina (variant angina).
• Rapid development of atherosclerotic obstruc­tion as in restenosis after PCI (percutaneous in­ervention).
• Acute ischemia secondary to exertion or anaemia.