Car 20 - Myocardial Infarction Part 2 Flashcards
What is a Subendocardial infarct?
Infarct that is less than 50% of wall diameter. Tend to affect smaller areas in the left ventricle, ventricular septum, or papillary muscle. They are particularly susceptible to infarcts because profusion from coronary arteries starts from the outside and comes inside. They tend to show ST depression.
What is a transmural infarct?
An infarct that affects the entire wall. Caused by atherosclertosis of major coronary artery. There will be a great deal of necrosis. Causes an ST segmentation elevation that can progress to Q wave.
What part of the heart wall does the Left Anterior Descending artery perfuse? What EKG leads would register it?
Perfuses the Anterior Wall. V1, V2, V3. A little of V4, V5. Causes ST segment elevations or T wave inversions.
What part of the heart wall does the Left Circumflex artery perfuse? What EKG leads would register it?
Perfuses the Lateral wall. EKG leads aVL, V5, V6.
What part of the heart wall does the Right coronary artery perfuse? What EKG leads would register it?
Two parts: Inferior wall* (detected in leads II, III, aVF), and Posterior wall (detected in Right precordial EKG: V4). * always obtain a right-sided EKG (V1-V6 on right chest) in inferior wall MI, this is ST segment elevation in V4, then posterior right ventricle also affected. This indicates a “right-sided MI”: give fluids and avoid NTG.
What are MI complications?
Cardiac arrhythmias. Ventricular failure and pulmonary edema. Cardiogenic shock. Ventricular free wall rupture: can lead to cardiac tamponade. Papillary muscle rupture (shows up as severe mitral regurg). Intraventricular septal rupture (causes a VSD). Aneurysm: can result in embolism from mural thrombus. Fribrinous pericarditis (friction rub, 3-5 days after MI, painful, relieved by sitting forward). Dressler syndrome (after 2 wks post-MI).
What is the initial treatment for Myocardial Infarction?
ABCs. MONA: IV Morphine, supplemental O2 (only if hypoxemia present), Nitroglycerin, Aspirin. Beta-blockers (metoprolol 25mg orally if no signs of HF or severe asthma). Statin (80mg of atorvastatin, preferably before PCI). Antiplatelet therapy to all patients (clopidogrel or ticagrelor). Anticoagulant therapy to all patients (unfractionated heparin to all patients undergoing PCI. Enoxaparin for patients not managed w/ PCI). K+ above 4, Mg+ above 2.
What is the treatment for a STEMI (ST segment Elevation MI) after initial treatment?
Percutaneous coronary intervention (cath). If PCI is unavailable then treat w/ fibrinolysis w/i 90-120 minutes
What is the treatment for a NSTEMI (Non-ST segment Elevation MI) after initial treatment?
Avoid fibrinolysis in patients w/ a non ST segment MI. Move them to PCI (percutaneous coronary intervention).
What is the long term management for Post-MI patients?
Aspirin and/or Clopidogrel. Beta-blocker. ACE inhib. ARBs. K+-sparing diuretics. Statins.
How do we decrease mortality in MI’s.
Beta-blockers. ACE inhib. Statins. Risk reduction (exercise, smoking cessation, dietary mod).
What would cause a Cardiac tamponade post-MI?
Rupture of ventricular wall.
What would cause severe mitral regurg post-MI?
Rupture of papillary muscle.
What would cause a new VSD post-MI?
Rupture of intraventricular septum.
What would cause a stroke post-MI?
Mural thrombus that can cause an embolus.
