Angina & ACS Flashcards
______ is the underlying cause of CAD and 90% of cases of MI and most heart failure
Atherosclerosis
Atherosclerotic plaques in coronary arteries can undergo fissuring or erosion, which triggers _____ formation to cause ischemia to the myocardium
Thrombus
Risk factors for atherosclerosis
Hyperlipidemia (high LDL, low HDL)
Smoking
DM
HTN
Family hx
Obesity
Physical inactivity
Psychosocial stress
Sleep disturbance
Age and gender
Characteristics of metabolic syndrome
Insulin resistance, increased BG
HTN
High TG, low HDL
Hyperuricemia
Hypercoagulability
Central obesity (BMI >30) or overweight (BMI 25-29)
Most frequent presenting symptom of myocardial ischemia
Angina pectoris
Chronic stable angina is a consequence of imbalance between ____ supply and demand; there is a ____ risk of plaque rupture in these pts (meaning there is small lipid core and thick fibrous cap)
oxygen; low
Compare supply angina vs. demand angina
Supply angina = decreased delivery of O2 to tissues leads to ischemia (i.e., coronary vasoconstriction, stenosis, platelets release 5-HT and TA2)
Demand angina = increased myocardial O2 requirements and workload lead to ischemia (i.e., exercise, stress, emotion, fever, thyrotoxicosis, LVH d/t AS, anemia)
Mechanical consequences of myocardial ischemia
Heart failure (L or R or both)
Angina (if ischemia is prolonged ro develop coronary occlusion, may lead to myocardial necrosis)
Segmental akinesis, bulging (dyskinesis) — aka wall motion abnormalities
Biochemical consequences of myocardial ischemia
Fatty acids can’t be oxidized
Increased lactate production
Reduced pH with metabolic acidosis
Electrical consequences of myocardial ischemia
Inversion of T wave
Transient displacement of ST segment (ST Depression=subendocardial; ST elevation=subepicardial)
Electrical instability: VT, VF
Area and artery affected if ischemic changes are seen in V1-V6
LAD —> anterior wall infarction
Artery and area affected if ischemic changes are seen in leads II, III, and aVF
RCA —> inferior wall infarction
Area affected if ischemic changes are seen in leads V3R-V6R
RV infarct
Artery and area affected if ischemic changes are seen in I, aVL, V5-V6
Circumflex a.; lateral wall infarct
Artery and area affected if ischemic changes are seen in V1-V3
Posterior descending artery; Posterior wall infarct
What information can an ST elevation on ECG tell you that an ST depression cannot?
Location/artery involved in infarct
Symmetric T wave inversion in the anterior precordial leads that were upright in prior ECGs indicates what?
LAD dz, possible anterior infarct
NOTE that T wave inversion is only significant if it is a CHANGE from previous ECG
A 58 y/o male presents to the ED with a hx of chest discomfort described as heaviness and pressure in retrosternal region. Pain radiates into base of neck and into jaw, and has been going on for 20 minutes. On PE he has S3 gallop and systolic murmur over apex with radiation into left axilla.
What is the cause of the S3 and the murmur?
S3 gallop may be “impending” LV dysfunction leading to heart failure
Murmur is likely MR d/t dysfunction of papillary m. during chest pain; location is inferior or inferior-posterior d/t RCA lesion
CV causes of chest pain
IHD (angina, UA, ACS, MI)
VHD
Pericarditis
Myocarditis
Cardiomyopathy
Non-cardiac causes of chest pain
Pleuritis Costochondritis Pneumonia PE-pulm infarct Pneumothorax GERD, PUD Gallstones Esophageal spasm Lung cancer Aortic aneurysm
Non-chest pain symptoms of chronic IHD
Dyspnea Mid-epigastric or abd pain Diaphoresis Excessive fatigue and weakness Dizziness and syncope
[epigastric pain often associated with inferior ischemia]
What is Levine’s sign?
Pt shows clenched fist as representation of their chest pain
Anginal equivalents are symptoms due to ischemia but described as dyspnea, fatigue, faintness, and gastric belching. This occurs d/t ischemia causing elevated LV filling pressure —> pulmonary edema. What patient populations tend to present differently with MI, like with “anginal equivalents”?
Diabetics
Elderly
Women
What are some PE findings that suggest risk factors for angina?
Xanthelasma Xanthomas Diabetic skin lesions Nicotine stains Pale Absent peripheral pulses
What are some cardiovascular exam findings that you may find in pts complaining of angina?
Abnormal cardiac impulse (LV dyskinetic)
Bruits — carotid, abominal aorta, femorals
Gallop — S3, S4, both
Systolic murmur of MR if papillary muscle is dysfunctional; associated with inferior or inferior-posterior ischemia d/t right CAD
What conditions can mimic angina in the absence of coronary artery disease?
AS AI Pulmonary HTN Hypertrophic cardiomyopathy Heart failure
What 2 criteria need to be met in order for a pt presenting with chest pain to be diagnosed with NSTEMI?
Elevation of cardiac enzymes (troponin I or CK-MB)
No ST elevation on ECG
What changes on ECG might be seen in pts with stable angina?
Normal in 50%
During anginal attack, may have displaced ST segment; most common change is ST depression (subendocardial injury-ischemia)
May show old MI (Q waves in corresponding leads to location of previous MI)
In terms of ECG findings in pts with unstable angina/NSTE ACS, the magnitude of _______ correlates with the pts prognosis
ST depression
T/F: pulmonary emboli may show ECG changes and elevated troponin
True — if it is a large enough PE to affect the LV and cause some cell death, cardiac troponin may be elevated
Characteristic ECG finding in pt with stress cardiomyopathy (takotsubo syndrome)
Deeply inverted T waves
What diagnostic labs would you order in someone with CAD that you suspect possible NSTEMI?
Cardiac enzymes (troponin I; detected in 2-4 hrs in NSTEMI)
Increased CK-MB after 3-6 hr
Increase in BNP (associated with increased mortality)
CRP
CMP, BUN, Cr, liver panel, electrolytes, CBC
Fasting lipid profile, TSH
What functional tests can be done to reveal presence of ischemia in pts with atherosclerotic CAD?
Exercise ECG, single photon emission (SPECT, PET)
Coronary flow (PET, fractional flow reserve)
Wall motion abnormalities (Echo, cardiac magnetic imaging - CMRI)
Signs with cardiac stress testing that indicate high risk for coronary event
Positive stress test at low workload
ST depression greater than 5 minutes after completion of test
Decrease in BP — systolic fall > 10 mm Hg during exercise
VT during exercise
Reduced EF during exercise (stress echo)
Exercise electrocardiography is preferred test if pt is suspected to have angina. What are contraindications to this test?
Recent MI or acute MI, unstable arrhythmias, acute PE, aortic dissection, unstable angina, severe AS, decompensated HF, endocarditis, DVT
Primary test recommended when baseline ECG findings are abnormal or when area of myocardium is at risk with exercise or when pt can’t exercise
Stress echocardiography
What test is useful in LBBB, LVH, or in digitalis effect?
Nuclear myocardial perfusion imaging
When is a pharmacological stress test indicated?
Pt unable to exercise; abnormal ECG with LBBB, LVH
What drugs are used in pharmacologic stress test?
Adenosine/regadenosine/dipyridamole — vasodilators that increase HR; vasodilate normal blood vessels more than diseased ones, then inject radioisotope - the amount taken up by heart muscle is directly proportional to blood flow
Can also use dobutamine to increase HR
_____ ______ provides anatomic diagnosis of severity of CAD; percutaneous revascularization can be performed after the study; risk in renal dysfunction bc exposure to radio contrast
Coronary angiography “cardiac cath”
Gold standard for anatomic definition of CAD
Coronary angiography
In what 2 circumstances is CABG preferred procedure above PCI?
L main disease
3 vessel disease
In coronary CT angiography, ability to quantify lesion severity can be limited by significant _____
Calcification
CXR findings in CAD
Usually normal, unless hx of MI, HF, or VHD
Cardiomegaly in HTN, VHD, cardiomyopathy, pericardial effusion
Pharmacologic therapies used to prevent MI and reduce symptoms
Aspirin Beta blocker ACEI Statins Nitro/nitrates CCBs
[note that nitrates and CCBs do NOT reduce mortality, but the rest do]
Contraindications to beta blockers
Decompensated HF
Hypotension
Advanced AV block
Drug useful in reducing maladaptive remodeling post-MI, especially in diabetics (renal protection), and patients with LV systolic dysfunction; reduces CV mortality
ACEI
Drug class used post-MI that is NOT shown to reduce mortality but vasodilates and reduces workload as well as decreases heartrate
Calcium channel blockers
MOA of ranolazine
Inhibits inward Na current and decreases intracellular Ca
What type of angina causes transient ST elevation during chest pain in the absence of severe CAD?
Prinzmetal angina
Prinzmetal angina is relieved by nitro; they should also be prescribed _________
Dihydropyridine CCB (amlodipine)
Angina management strategies in low risk patients
Antianginal therapy — BB, nitro, CCB
Statin
Antiplatelet — ASA, clopidogrel
Anticoagulant — UF heparin
Cath: revascularization if appropriate [when refractory to other therapy]
Management strategies of angina in high risk pts
Antianginal- BB, nitro, CCB
Statin for plaque stabilization and restoration of endothelial function
Antiplatelet - ASA, clopidogrel or prasigrel or ticagrelor glycoprotein inhibitor
Anticoagulant - UFH or enoxaparin or bivalirudin or fondiparinux
Cath: revascularization if appropriate (refractory to other therapy)
