Acute Coronary Syndrome DETAILED Overview (MI, STEMI, NSTEMI)

Summary

This video covers acute coronary syndrome (ACS), a condition caused by reduced or blocked blood flow to the heart. It explains the heart’s anatomy, the coronary arteries, and how plaque buildup leads to conditions like stable angina, unstable angina, and myocardial infarction (heart attack). The video highlights the role of non-ST elevation myocardial infarctions (NSTEMI) and ST-elevation myocardial infarctions (STEMI), their diagnosis using ECG and cardiac markers like troponin, and their treatment through interventions like PCI or fibrinolytic therapy. It concludes with potential complications and long-term management strategies.

Takeaways

• 🫀 Acute coronary syndrome is characterized by a reduction or total occlusion of blood supply to the heart.
• 🫁 The heart receives its blood supply from the right and left coronary arteries; the left further divides into the left anterior descending and circumflex arteries.
• 🧬 Atherosclerotic plaque buildup in coronary arteries, often due to non-modifiable factors like aging, male sex, and ethnicity, can reduce blood flow and cause chest pain (angina).
• ⚠️ Unstable angina causes chest pain even at rest, and when plaques rupture, they can cause thrombosis, leading to myocardial infarction (heart attack).
• 📉 A non-ST-elevation myocardial infarction (NSTEMI) occurs when the artery is partially occluded, while a ST-elevation myocardial infarction (STEMI) occurs with complete artery occlusion.
• 💉 Key diagnostic markers for heart attacks include elevated levels of troponin and creatine kinase MB (CK-MB) in the blood, which indicate heart muscle necrosis.
• 🫀 ECG changes, such as ST-segment elevation or depression, help differentiate between STEMI and NSTEMI, and are vital for diagnosis.
• ⚕️ Management of acute coronary syndrome includes the acronym MOAN: Morphine, Oxygen, Aspirin, and Nitrates, followed by definitive treatments like PCI (angioplasty) or thrombolysis.
• 📉 Cardiac markers are normal in stable and unstable angina but elevated in STEMI and NSTEMI.
• 🧑‍⚕️ Long-term management includes lifestyle modifications and medications like ACE inhibitors, beta-blockers, aspirin, and statins to prevent recurrence.

Q & A

What is acute coronary syndrome (ACS)?

Acute coronary syndrome (ACS) refers to a range of conditions caused by a reduction or complete blockage of blood supply to the heart muscles, leading to varying degrees of damage or ischemia. It includes unstable angina, non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI).

What are the main arteries that supply the heart with blood?

The heart is supplied with blood by two main coronary arteries: the right coronary artery (RCA) and the left coronary artery (LCA). The left coronary artery further branches into the left anterior descending (LAD) artery and the left circumflex (LCX) artery.

What causes angina, and how does it differ between stable and unstable angina?

Angina is chest pain caused by reduced blood flow to the heart muscle. Stable angina occurs during exertion and subsides with rest, while unstable angina can occur even at rest and indicates a more serious condition that may lead to a heart attack.

What is the difference between STEMI and NSTEMI?

STEMI (ST-segment elevation myocardial infarction) occurs when there is a complete occlusion of a coronary artery, leading to full-thickness heart muscle damage. NSTEMI (non-ST-segment elevation myocardial infarction) involves partial occlusion, causing partial heart muscle damage. The key difference is seen in the ECG, where STEMI shows ST-segment elevation, while NSTEMI shows ST-segment depression.

What are the risk factors for developing acute coronary syndrome?

Risk factors for acute coronary syndrome include non-modifiable factors such as age, male gender, family history, and certain ethnicities (e.g., Caucasians). Modifiable risk factors include smoking, hypertension, high cholesterol, obesity, poor diet, diabetes, and a sedentary lifestyle.

What are troponin and creatine kinase-MB (CK-MB), and why are they important in diagnosing myocardial infarction?

Troponin and CK-MB are proteins released into the bloodstream when heart muscle cells are damaged, such as during a heart attack. Elevated levels of these cardiac markers are crucial for diagnosing myocardial infarction, as they indicate heart muscle necrosis.

What ECG changes are associated with STEMI and NSTEMI?

In STEMI, the ECG shows ST-segment elevation, which indicates full-thickness myocardial infarction. In NSTEMI, there is ST-segment depression or T-wave inversion, indicating partial-thickness infarction.

What is the initial management of acute coronary syndrome?

The initial management of acute coronary syndrome is often summarized by the acronym MOAN: Morphine (for pain relief), Oxygen (if levels are low), Aspirin (to reduce clot formation), and Nitroglycerin (to improve blood flow by dilating the coronary arteries).

What is the definitive treatment for STEMI?

The definitive treatment for STEMI is emergency reperfusion therapy. The first-line treatment is primary percutaneous coronary intervention (PCI), where a balloon and stent are used to open the blocked artery. If PCI is unavailable, fibrinolytic therapy (thrombolysis) is used to dissolve the clot.

What are some complications that can occur after a myocardial infarction?

Complications after a myocardial infarction include arrhythmias, heart failure, ventricular rupture, mitral regurgitation, pericarditis, and pulmonary embolism. Late complications can include Dressler syndrome (post-myocardial infarction pericarditis) and chronic heart failure.