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Questions and Answers
What is the most common cause of coronary artery disease (CAD) discussed in the video?
Which artery is responsible for supplying the right side of the heart and can lead to AV blocks when occluded?
In stable CAD, what results from atherosclerotic plaques causing luminal stenosis?
Which condition presents with intensified angina at rest?
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What is a possible complication of myocardial infarction that may lead to ventricular tachycardia or fibrillation?
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Which complication of myocardial ischemia post-infarction can cause a decrease in left ventricular ejection fraction and cardiac output?
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Which condition can lead to a holosystolic murmur and left heart failure post-MI?
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What can result from a contained rupture due to LED occlusion post-MI?
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Which test is considered the test of choice for patients with STEMI?
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What are positive stress test indicators during stress testing?
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Study Notes
- The video discusses coronary artery disease (CAD), focusing on the anatomy of coronary vessels supplying the heart.
- Four main coronary vessels are highlighted: posterior descending artery, right coronary artery, left anterior descending artery (LAD), and left circumflex artery (LCX).
- Atherosclerosis, characterized by fatty plaques in blood vessel walls, is the most common cause of CAD.
- Risk factors for atherosclerosis include smoking, advanced age, diabetes, high cholesterol (specifically high LDL and low HDL), hypertension, and a family history of CAD.
- In stable CAD, atherosclerotic plaques cause luminal stenosis, reducing oxygen supply to the myocardium.
- Increased oxygen demand due to factors like elevated heart rate or high blood pressure can lead to ischemia in stable CAD patients, resulting in angina.
- Plaque rupture in CAD can lead to thrombus formation, causing a sudden decrease in oxygen supply and potentially leading to acute coronary syndromes like unstable angina, NSTEMI, or STEMI.
- Unstable angina presents with intensified angina at rest, while NSTEMI involves sub-endocardial ischemia without tissue death, and STEMI results in transmural infarction with positive troponins and ST-segment elevation.
- Complications of infarction can include arrhythmias (e.g., AV blocks from RCA occlusion, re-entrant circuits from LAD or LCX occlusion), which may lead to bradycardia or ventricular tachycardia/fibrillation.
- Acute heart failure can also occur as a complication of myocardial ischemia post-infarction, especially within the first 24 hours.- LED occlusion can lead to dropping left ventricular contractility, causing a decrease in left ventricular ejection fraction and cardiac output, potentially leading to hypotension and cardiogenic shock.
- Blood backing up into the left atrium due to ventricular septal defect can lead to a murmur and heart failure, more commonly right heart failure.
- Papillary muscle rupture due to occlusion can cause acute mitral regurgitation, leading to a holosystolic murmur and left heart failure.
- Free wall rupture from a large LED occlusion can result in hemopericardium and cardiac tamponade, characterized by Beck's triad and muffled heart sounds.
- A contained rupture from LED occlusion can create a pseudoaneurysm, increasing the risk of thromboembolic complications like stroke.
- Pericarditis can result from inflammation extending to the nearby pericardium after an infarct, presenting with pleuritic chest pain and a friction rub on auscultation.
- Differentiating between fibrinous and Dressler's pericarditis can be based on timing post-MI, with fibrinous occurring 1-3 days after and Dressler's about 14 days post-MI.
- Diagnosing myocardial ischemia includes starting with an EKG, normal troponin supporting stable angina, while positive troponin indicates unstable angina or NSTEMI/STEMI.
- Localizing an MI with EKG leads helps identify the occluded vessel, with anterior (V1-V4), inferior (II, III, aVF), lateral (I, aVL, V5, V6), and posterior (V7-V9) areas corresponding to different vessels.
- ECG findings correlated with echocardiogram wall motion abnormalities can aid in confirming the location of the occlusion and guiding treatment decisions.
- For patients with STEMI, the test of choice and therapeutic intervention is a coronary angiogram to locate and treat the occlusion by inserting a stent.- Different options for stress testing include baseline ECG, myocardial perfusion imaging, and echocardiogram to assess heart function.
- During stress testing, patients are made to exercise to reach target heart rate and monitored for symptoms or arrhythmias.
- Positive stress test indicators include signs of ischemia on ECG, areas of poor perfusion on MPI, or wall motion abnormalities on echocardiogram.
- Reasons for choosing MPI or echocardiogram over ECG include abnormal ECG findings like left bundle or Q waves.
- Patients unable to exercise can undergo pharmacological stress testing with drugs like adenosine or dipyridamole to induce stress.
- Adenosine or dipyridamole causes coronary steal syndrome, reducing blood flow to diseased vessels during stress testing.
- Positive stress test results may lead to further evaluation with coronary angiogram or coronary CTA to assess vascular lesions.
- Treatment for stable CAD includes aspirin, nitroglycerin, beta blockers, calcium channel blockers, and potentially revascularization.
- Revascularization options for significant CAD include PCI for less severe cases and CABG for more complex cases.
- Dual antiplatelet therapy is crucial post-PCI to prevent stent thrombosis, typically involving aspirin and clopidogrel for at least one year.
- For unstable angina and NSTEMI, dual antiplatelet therapy (aspirin + clopidogrel) with heparin is given before revascularization.
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Description
Explore the anatomy of coronary vessels, causes of CAD, complications of MI, diagnostic tests like EKG and stress testing, treatment options including revascularization, and medications like dual antiplatelet therapy. Understand the pathophysiology of stable and unstable CAD, different types of MI, and how to localize infarctions based on EKG findings.
