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123 Cards in this Set
- Front
- Back
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Coronary Artery Disease |
- Most common problem encountered in US adults |
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Ischemia |
- Inadequate blood supply to the myocardium - Myocardial contraction becomes abnormal immediately after the onset of ischemia |
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Order of Ischemia Occurrences |
1. Ischemia 2. RWMA 3. EKG Changes 4. Pain |
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Coronary Angiogram |
- Invasive procedure - Visualizes coronary arteries directly - Gold standard for assessing coronary artery anatomy |
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Role of Echo in CAD |
- TTE and TEE should detect most, if not all mechanical complications of MI - Use stress echo to predict myocardial viability and prognosis/detecting CAD - Early detection of MI (before EKG changes) |
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Angiogram |
- Patient is awake but lightly sedated - Use catheter entered through the femoral or radial artery and threaded through to the coronary arteries - Watch fluoroscope on screen and inject contrast dye to visualize arteries and look for blockages and determine whether intervention is needed |
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Atherosclerosis |
Hardening of plaque forming in artery. |
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Angioplasty (PTCA) |
- Procedure to open blocked arteries - PTCA: Percutaneous Transluminal Coronary Angioplasty - Use tiny balloon to push plaque into wall - Sometimes put a stent in, a stent is a small metal coil or tube to prevent artery from narrowing |
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Atherectomy |
- Use catheter with grinding device to find plaque into small bits which float away into bloodstream |
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CABG |
- Coronary Artery Bypass Graft - Performed when multiple arteries are blocked with diffuse disease (spread out over a lot of the heart) |
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Angina |
- Chest pain due to myocardial ischemia that is not associated with clinical evidence of acute MI - 3 Types: stable, unstable, and Prinzmetal's |
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Stable Angina |
Occurs with exercise and is relieved by rest or medications. |
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Unstable Angina |
May occur at rest or during sleep or may indicate a notable change in the nature of previously stale angina (pre-infarction angina). |
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Prinzmetal's Angina |
- Occurs exclusively at rest and usually during the night - Due to coronary spasm |
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Asymptomatic Ischemic Disease |
- Diabetics are prone to this - 2/3 of people with diabetes mellitus die of some form of heart or blood vessel disease |
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Medications Used in CAD |
- Nitrates - Beta Blockers - Calcium Channel Blockers - Digitalis Glycosides |
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Nitrates |
- Names: Isordil, Isosorbide dinitrate, cardilate, nitrobid, Nitroglycerin - Vasodilators - Relax the smooth muscle in veins/arteries/arterioles - Reduce RV and LV preload and afterload - Decreases cardiac work - Lowers myocardial oxygen requirement - 1st drug of choice for treating acute angina |
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Beta Blockers |
- Names: Inderal, corgard, lopressor, tenormin, atenolol - Reduces HR at rest and during exercise - Reduces contractility which effects myocardial demand - Reduces systemic BP - Blocks effects of epinephrine and adrenaline |
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Calcium Channel Blocker |
- Names: Calan, cardizem, diltiazem, nifedipine, procardia, verapamil - Potent arterial/coronary vasodilator - Decreases myocardial contractility - Decreases HR - Increases coronary flow |
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Digitalis Glycosides |
- Names: Digoxin, lanoxin - Increases peripheral and coronary vascular resistance - Increases the contractile state of the myocardium - Increases HR - Promotes elimination of fluid from tissues - Used to treat some arrhythmias |
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ACE Inhibitors |
- Angiotensin converting enzyme inhibitors - Prevents constriction of blood vessels - Decreases afterload - Increases contractility |
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Antiarrythmics |
- Lidocaine - Bretylium - Procainamide |
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Antihypertensives |
Lopressor |
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Diuretics |
- Fluid reduction - Lasix - Furosemide |
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Coronary arteries and their branches: |
Right coronary artery--branches to posterior descending artery (70% of the time) and acute marginal artery Left main coronary artery--branches to left anterior descending artery and left circumflex artery |
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When do the coronary arteries fill with blood? |
Mostly during diastole. |
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Coronary Artery Dominance |
- Where the posterior descending artery originates - PDA supplies basal 1/3 of the septum - RCA--70% (right dominant) - LCA--10% (left dominant) - RCA and LCX--20% (co-dominant |
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How much of the myocardium is supplied by each artery? |
LAD- supplies 50% of the myocardium RCA- supplies 25% of the myocardium LCX- supplies 25% of the myocardium PDA- supplies the basal 1/3 of the septum |
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Wall Motion Scoring |
1- Normal 2- Hypokinetic 3- Akinetic 4- Dyskinetic 5- Aneurysmal |
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1- Normal Wall Motion |
Systolic contraction and wall thickening increase more than 50% |
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2- Hypokinetic Wall Motion |
Reduced systolic wall thickening (<40%) |
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3- Akinetic Wall Motion |
Diastolic wall thickness is usually thin and systolic wall thickening of less than 10% (or no thickening) |
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4- Dyskinetic Wall Motion |
Diastolic wall thickness is think and movement of the myocardium is outward in systole |
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5- Aneurysmal Wall Motion |
Constantly deformed segment throughout cardiac cycle |
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WMSI (Wall Motion Score Index) |
WMSI = sum of wall motion score / # of segments visualized 1 = Normal (any greater means infarct) |
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Stress Testing Purpose |
- To induce ischemia by increasing oxygen demand. - To increase cardiac workload to elicit signs of physiologic dysfunction in many types of cardiac disease - GOAL: for patient to reach target heart rate |
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Types of Stress Testing |
- Stress EKG - Exercise Stress Echo (treadmill, supine bike, upright bike) - Pharmacological (dobutamine) |
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Stress EKG |
- Patient hooked to 12 lead EKG - Take resting BP and EKG - Exercised according to protocol - END POINTS: target HR, EKG changes, abnormal BP change, symptoms * not as sensitive as stress echo * |
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Treadmill Stress Echo Indications |
- CAD (known or suspected) - Chest pain, shortness of breath - Before surgery/intervention (determine risk) - Abnormal EKG - Evaluate LV function - Identity viable, hibernating, or stunned myocardium - Evaluate hemodynamics in valvular/cardiomyopathy heart disease |
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Treadmill Stress Echo |
- Combines baseline echo with peak/post exercise echo to detect and assess known or suspected CAD - 12 lead EKG in addition to echo imaging |
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Contraindications for TSE |
- Acute MI (within 2 days) - Unstable angina - Uncontrolled ventricular arrythmias - Symptomatic AS (resting gradient >50 mmHg) **may cause them to pass out - Acute pulmonary embolism - Acute myocarditis/pericarditis - Pregnancy |
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TSE Procedure |
- Patient hooked to 12 lead EKG - Take resting BP, EKG, and echo (evaluate valves, ventricular function, acquire before images) - Exercised according to protocol (Bruce protocol) - END POINTS: reaches target HR+, EKG changes, abnormal BP changes, symptoms, end of protocol reached - Immediately POST exercise: attain images within 60 seconds ( A2C, A4C, PLAX, PSAX pap.) |
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Bruce Protocol |
Target HR = 220 - age - 3 minute stages - % grade and mph change every 3 minutes - Protocol starts at 10% grade and 1.7 mph |
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Advantages/Disadvantages TSE |
Advantages: - non-invasive - high total workload Disadvantages: - imaging only done after exercise - WMA's may resolve quickly and be missed |
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Dobutamine Stress Echo |
- Use medication via IV infusion instead of physical exercise to raise HR and mimic effects of exercise - Done on patients unable to exercise |
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Dobutamine Stress Echo Procedure |
- Patient hooked to 12 lead EKG - Take resting BP, EKG, and echo (evaluate valves, ventricular function, acquire before images) - Saline IV started by RN prior to resting echo - Infusion of dopamine begins (started at 5 mpg/kg/min and increased at 3 minute intervals (5, 10, 20, 30) - Echo images acquired at low dose and peak dose as well as recovery - Absolute end point: target HR reached |
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Supine Bike Stress Echo Protocol |
- Begins at workload of 25 watts and a cadence of 60 rpm - Increased by 25 watts every 2 minutes - Images acquired throughout exercise |
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Supine Bike Stress Echo Advantages/Disadvantages |
Advantages: - Able to images throughout exercise, particularly at peak stress Disadvantages: - Some patients find bicycling in the supine position difficult, and inadequate levels of stress may be achieved - May be hard to scan because they move as they bike |
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Normal at rest, Hyperkinetic when stressed |
Interpreted as normal |
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Normal at rest, Hypokinetic/Akinetic when stressed |
Interpreted as ischemic |
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Akinetic at rest, Akinetic when stressed |
Interpreted as infarction |
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Hypokinetic at rest, Akinetic/dyskinetic when stressed |
Interpreted as ischemic and or infarction |
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Hypokinetic/Akinetic at rest, Normal when stressed |
Determines that the myocardium is still viable |
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Positive Stress Echo |
- Normal wall motion at rest becomes hypokinetic, akinetic, or dyskinetic when stressed - Wall motion after exercise fails to become hyperdynamic - Increase in size of LV and or shape after exercise - Decrease in EF |
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Negative Stress Echo |
Normal |
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Positive SEKG with Negative SE |
SEKG thought to be a false positive. |
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LV Volume Changes during Stress |
Normal Response: - A decrease in both ESV and EDV Abnormal Response: - Failure of the ESV to decrease - Increase in both ESV and EDV usually indicates severe and extensive multi-vessel disease |
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False Negative Stress Echo |
- Inadequate response to stress by not reaching target HR - Mild CAD or single vessel disease present - Collaterals have formed |
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False Positive Stress Echo |
- Hypertrophic Cardiomyopathy - Hypertension |
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Ischemia |
Ischemia: - Myocardium will appear hypokinetic/akinetic - WMA will return to baseline between ischemic events - Reversible WMA |
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Hibernating Myocardium |
Hibernating Myocardium: - Reversible WMA - Due to chronic disease in blood supply - Viable myocardium |
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Stunned Myocardium |
Stunned Myocardium: - Occurs after reperfusion therapy - Reversible WMA - Viable myocardium |
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Other Modalities to Assess Ischemia |
- Doppler SE - Intravascular US - Contrast agents to assess perfusion - CT angiography - Cardiac MRI - Nuclear medicine stress test - PET imaging - Angiography (gold standard) |
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Sensitivity |
% of sick people correctly identified as having the disease 100%--predicting all sick people as being sick |
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Specificity |
% of healthy people correctly identified as not having the disease 100%--not predicting any healthy people as having the disease |
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Which leads are related to which parts of the heart? |
Inferior: II, III, aVF Septal: V1, V2 Anterior: V3, V4 Lateral: I, aVL, V5, V6 RV Infarct: V4R |
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P Wave |
Atrial systole/depolarization |
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PR Interval |
Onset of atrial depolarization to onset of QRS (ventricular depolarization) |
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QRS Complex |
Ventricular systole/depolarization |
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ST Segment |
Represents period when ventricles are depolarized. |
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T Wave |
Ventricular repolarization |
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How many electrodes in a 12 lead EKG? |
10 (6 on chest, 4 on limbs) |
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Chest Leads |
V1-V6 |
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Bipolar Leads |
Limb leads (I, II, III) |
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Unipolar Leads |
Augmented limb leads (aVR, aVL, aVF) Precordial leads (V1, V6) |
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ST Depression
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- Any lead but aVR - Ischemia - Subendocardial infarct - During exercise, its a positive stress test |
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ST Elevation |
- Any lead but aVR - Also called STEMI - Acute MI - Could also be pericarditis/tamponade/cardiac contusion |
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Q Waves (Significant vs. Insignificant) |
Significant: 1 mm wide (one small square), and/or at least 1/3 the height of the QRS
Insignificant: Does not meet above criteria - any lead but aVR |
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Flattened T Waves |
- in leads V2-V6 Ischemia |
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Inverted T Waves |
- in leads V2-V6 Ischemia |
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Atherosclerosis |
- Disease of the intima (inner layer of artery) - Gets thick with fatty deposits, calcium, and fibrous tissue (lumen gets smaller) - Has to be 75% narrowed for symptoms on exertion - Has to be 90% narrowed for symptoms at rest - How well myocardium works is better prognosis than how badly occluded arteries are. |
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Arteriosclerosis |
- Characterized by hardening, loss of elasticity, and thickening of arterial walls - Results in decreased blood supply |
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Ischemia |
- Inadequate perfusion - Reversible - See hypokinetic or akinetic RWMA |
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Most deaths from infarcts occur with: |
Anteroseptal infarcts |
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Most hospitalizations from infarcts occur with: |
Inferoseptal infarcts |
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Infarction |
- Dead myocardium - Irreversible - See akinetic or dyskinetic RWMA |
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Acute MI |
- Akinetic wall motion with normal wall thickness - Opposing walls may be hyperkinetic - ST segment elevation usually seen on EKG |
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Old MI |
- Akinetic wall motion with thinned echogenic myocardium - Significant Q waves may be present on EKG |
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Transmural MI |
- Injury > 50 % of myocardium thickness |
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Subendocardial MI/Non Q wave MI |
- Injury < 50 % of myocardial thickness |
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Silent MI |
- Asymptomatic - Up to 1/3 of MI's are silent - Often seen with diabetic patients |
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Stunned Myocardium |
- Associated with reperfusion therapy - WMA may last up to 72 hrs after therapy |
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Hibernating Myocardium |
- Prolonged ischemia - Reversible - Bi-phasic response to dopamine |
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Echo Assessment to Rule Out MI |
- Use all windows to assess wall motion - Must see endocardium!!! - Assess diastolic function - Be aware of imaging pitfalls |
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Diagnosing MI |
Two of the following: - Symptoms - EKG changes - Cardiac enzymes |
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Cardiac Enzymes |
Proteins from the heart muscle cells that are released into the bloodstream when heart muscle is damaged. |
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Troponin |
- Cardiac enzyme - Early marker of cardiac cell damage - Elevates 3-6 hrs after MI - Peaks 10-24 hrs after MI - Falls > 7 days |
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Creatine Kinase |
- Cardiac enzyme - Later marker of cardiac cell damage - Elevates in 3-12 hrs after MI - Peaks in 12-24 hrs after MI - Falls in 1-3 days |
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What cardiac enzyme is useful in patients who present late? |
Lactic Dehydrogenase (LDH) |
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What enzyme is released when body tissue is damaged and isn't specific to the heart? |
Aspartate Transaminase (AST) |
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Different Methods to Diagnose MI |
- Perfusion study (good specificity) - Echo (portable, better sensitivity) - Coronary Angiogram (both diagnosis/intervention) - Cardiac Short Stay Units: non diagnostic but suspicious for ruling out MI (monitor things before doing anything invasive) |
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Infarction Stages |
Week 1: Inflammation stage (increase WBC's) Week 2: Clean up stage Week 3-4: Healing phase (scar formation) |
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Ischemic Heart Disease |
- Impaired systolic function due to numerous MI's over time - Definite areas of akinesia or thinned myocardium - MR in absence of MV abnormalities - Elevated PA pressures |
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Chronic Valve Disease |
- Mitral regurgitation due to anatomic abnormalities of the mitral valve - LV enlargement due to systolic dysfunction - High PA pressures |
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Dilated Cardiomyopathy |
- Often idiopathic - More global WMA's than specific RWMA - Usually both RV and LV are dilated - MR in absence of MV abnormalities - Moderate to severe TR - Elevated PA pressures |
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Warning signs of MI |
- Chest discomfort - Upper body discomfort - Shortness of breath - Nausea - Lightheadedness - Anxiety |
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What percentage of patients with coronary atherosclerosis who suffer an acute cardiac arrest will die within one hour? |
50% |
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Of the patients that survive and have a diagnosis of acute MI, what percentage will have an uncomplicated hospital course? |
50%, the other 50% will experience one or more complications |
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Complications of MI |
- LV remodeling - True aneurysm - Pseudoaneurysm - Cardiac rupture - LV thrombus - Dressler's syndrome - Cardiogenic shock - RV infarct |
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LV Remodeling |
- Volume does not get bigger but infarcted region begins to stretch and thin - Outward bulging of the infarcted wall during systole - Not a good prognosis |
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True Aneurysm |
- Lined by myocardium - Wall motion is dyskinetic & fixed - Area of bulging result in wall thinning and or infarct expansion - Apical aneurysms are most common - Usually don't rupture once healed - 50% are filled with thrombi - Only found in transmural infarctions |
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Pseudoaneurysm |
- Chronic, contained ventricular rupture - Wall is made of pericardium - Narrow neck from LV into pseudo aneurysm - Only found in transmural infarctions - Surgical repair necessary due to high chance of spontaneous rupture |
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Cardiac Rupture |
- Catastrophic and often fatal complication of acute MI - Tends to occur in first week - Infarcted wall is maximally soft and weak - Types: free wall, ventricular septal, papillary muscle |
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Free Wall Rupture |
- Blood enters pericardium causing pericardial tamponade - Life threatening unless sealed by thrombus - Rapidly fatal in 85% of cases - Only found in transmural infarctions |
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Ventricular Septal Rupture |
- Acute VSD: shunt between LV and RV - New, loud, harsh systolic murmur - Bad prognosis: makes up 10% of rupture cases - 50% mortality |
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MV Papillary Muscle Rupture Types |
Partial: rocking or flapping of papillary muscle Complete: flail MV with an attached mass in LA |
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MV Papillary Muscle Rupture |
- 80% posteromedial pap. muscle - 20% anterolateral pap. muscle - New systolic murmur - Better prognosis: makes up 5% of rupture cases |
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Conditions for thrombus formation: |
- Area of dilation - Area of WMA - Presence of spontaneous echo contrast ("smoke" in the LV) |
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Types of LV Thrombus |
Pedunculated thrombus: - protrudes into LV cavity Mural thrombus: - adheres to endocardium |
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Dressler's Syndrome |
- Post-infarction syndrome occurs weeks to months after MI - Characterized by: recurrent low grade fever, pleropericardial chest pain, pericardial friction rub, pleural effusions, pericardial effusion |
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Cardiogenic Shock |
- Cannot maintain CO - May lead to death - Complication of large MI (>40% loss of LV mass) |
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RV Infarct |
- Associated with LV inferior wall infarct - Assess for WMA or chamber enlargement - Observe for right heart failure |
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Pericardial Effusion |
Fluid in pericardial space |
