ischemic heart disease Flashcards
ischemic heart disease is synonymus with what
- coronary heart disease
- coronary artery disease
what causes ischemic heart disease
- imbalance between myocardial oxygen supply and oxygen demand
- increasing stenosis is associated with inability to meet increased demand
causes of gradual vs sudden ischemic heart disease
- gradually: progressive narrowing of coronary arteries
- suddenly: rupture of a “vulnerable plaque”
what three conditions make up ischemic heart disease
- atherosclerotic disease
- angina pectoris
- acute coronary syndrome
what is the # 1 killer in the US
ischemic heart disease
why are women 10 times more likely to die from IHD than breast cancer
- women generally have atypical symptoms
- 33% have no CP
- 58% have dyspnea
ischemic heart disease most commonly affects what age population
- > 45 y.o
subpopulations < 45 yo have increased risk of heart disease if
- use cocaine
- type I DM
- hypercholesterolemia
- family hx of early onset heart disease
describe the process of artherogenesis
- endothelial damage plays a key role in the development of atherosclerosis
- lipids undergo oxidation and deposit in the arterial intima, beneath endothelium
- an inflammatory process occurs in intima, with macrophages and lymphocytes, which mature into lipid-laden “foam cells”
- a “fatty streak” develops, which is a precursor to fully formed artherosclerotic plaques
how does plaque rupture lead to coronary thrombosis
- platelet rupture
- platelet adhesion
- platelet activation
- platelet aggregation
- occlusive thrombosis + vasoconstriction
function of intravascular ultrasound
- technique for veiwing plaque embedded in coronary artery walls which would not be detected by routine angiography
right coronary artery branches into what
- posterior descending artery
- right marginal artery.
left coronary artery has what branches
- anterior interventricular artery (left anterior descending)
- left circumflex artery
the left marginal artery is a branch off of what artery
left circumflex artery
most of the perfusion of the myocardium occurs during systole or diastole
diastole
the main arteries are located in the epicardial region and blood flows from
- epicardium to endocardium
where do atherosclerotic plaques normally form in coronaries
- at sites of increased turbulance, such as branching points
when ischemia is transient, it may result in . When it is more prolonged, it may result in .
- angina pectoris
- myocardial infarction
acute coronary syndrome is broken down into what categories
- unstable angina
- myocardial infarction
- STEMI
- NSTEMI
clinical presentation
- heaviness, pressure, squeezing, tightness, smothering pain
- location: substernal
- radiation: shoulders, arms, neck, jaw, teeth, epigastrium, mid back
- duration: 2-5 minutes
- relief: stopping activity, rest, sublingual nitroglycerin
Angina pectoris
Levin’s sign
- clenched fist over sternum
- frequently demonstrated by patients experiencing ischemic chest pain
what are some atypical symptoms of myocardial ischemia
- dysnpnea
- nausea
- fatigue
- faintness
- *more common in elderly and diabetic patients
because IHD is commonly associated with atherosclerotic disease elsewhere, what should be included in PE
- BP
- skin for xanthomas and xanthelasmas
- fundus for A-V nicking
- carotids for pulse and bruits
- cardiac auscultation
- abdomen for aortic size and bruits
- extremities for pulses and edema
define stable angina
- exertional or stress-related chest or arm discomfort that resolves with rest and/or the use of sublingual nitroglycerin
- usually not greater than 5-10 minutes
define unstable angina
- ischemic discomfort with at least one of the following features
- occurs at rest (or minimal exertion), usually lasting > 10 min
- severe and of new onset (w/in prior 4-6 weeks)
- occurs with a crescendo pattern
- more severe or
- more prolonged or
- more frequently than previously
What is Prinzmetal’s angina
- chest pain occuring at rest, associated with transient ST-segment elevation
- ischemic symptoms secondary to vasospasm
- usually younger patients with fewer risk factors
treatment for Prinzmetal’s angina
- nitrates and calcium channel blockers
EKG changes consistent with stable angina
- resting ECG may be normal
- ST-T wave changes that occur during an episode of chest pain and then resolve afterwards are consistent with angina
Bruce Protocol of exercise stress test
- speed and incline are increased every three minutes until patient’s HR is at 85% of the patients maximum HR predicted for their age
- look for
- ECG changes
- decreased myocardial perfusion seen on nuclear imaging
- drop in systolic BP > 10 mmHg
- symptoms
Give all methods of stress testing
- stress modality
- exercise
- pharmacologic
- imaging
- ECG
- Echo
- Nuclear
list indications for pharmacologic stress testing
- patient is unable to exercise due to
- neurologic deficits
- rheumatologic or ortho conditions
- chronic lung disease
- debilitation, old age
- beta-blocker: not able to achieve target HR
- poor exercise tolerance
populations in which exercise stress testing can be unreliable
- women
- eldery
- obese
- debility
- bundle branch block
- pacemaker
stress echocardiogram can diagnosis ischemia related to ? when are peak-stress images obtained
- development of wall motion abnormality with exercise/stress
- peak-stress images are obtained once patient reaches 85% of predicted HR
MOA of nuclear medicine imaging
- thallium is concentrated in areas of the myocardium with adequate blood flow and living myocardial cells
- rest images are obtained initially
- exercise/stress images are obtained
- a perfusion defect will be seen in areas of hypoperfusion
what is the gold standard for diagnosing CAD
coronary angiography
- however, it does not demonstrate the presence of a “vulnerable plaque” which could rupture
evidence for plant based diet in prevention of CAD
- CAD is virtually absent in cultures that eat primarily plant based diets
- optimal diet
- gains, legumes, vegetables, fruit
- <10-15% calories from fat
risk factor modification treatment of stable angina
- risk factor modification
- smoking cessation
- treat HTN
- glucose control
- statin therapy
- weight reduction
- physical conditioning
name three classes of medicines that decrease oxygen demand
-
nitrates: preload reduction
- nitroglycerin
- beta-blockers: decrease HR, BP, and contractility
- calcium channel blockers: decrease BP and contractility
what is the first line medicinal treatment for chronic angina
beta blockers
calcium channel blockers are indicated for which patients
patients who don’t respond to nitrates and beta blockers
name medications that increase oxygen supply
- nitrates
- calcium channel blockers
function and dosing of Nitrates
- function: dilate coronary arteries
- dosing:
- 0.3-0.6 mg sublingually
- give at onset of pain and every 5 minutes for up to 3 doses
function of calcium channel blockers
coronary vasodilators
name the common antiplatelet medication used in treatment of IHD
- aspirin (75-325 mg daily)
- clopidogrel (plavix)
- combo of two
indication for percutaneous coronary intervention
- function: revascularization
- history of angina despite medical treatment; evidence of ischemia on stress testing
- cardiologist feeds a deflated balloon on a catheter from the inguinal femoral artery or radial artery up through blood vessels until they reach the site of blockage in the heart. At the blockage, the balloon is inflated to open the artery, allowing blood to flow. A stent is often placed at the site of blockage to permanently open the artery
indication for coronary artery bypass grafting (CABG)
- left main coronary stenosis
- triple vessel disease
- During CABG, a healthy artery or vein from the body is connected, or grafted, to the blocked coronary artery. The grafted artery or vein bypasses the blocked portion of the coronary artery. This creates a new path for oxygen-rich blood to flow to the heart muscle
- typically use saphenous vein or internal mammary arteries
name the three acute coronary syndromes
- unstable angina
- NSTEMI
- STEMI
in addition to the typical ischemic pain, patients with acute coronary syndrome may experience
- SOB
- weakness
- nausea
- anxiety
- sense of doom
name the 4 pathophysiological processes that can cause unstable angina/NSTEMI
- plaque rupture or erosion with superimposed nonocclusive thrombus (most common cause)
- dynamic obstruction (coronary artery spasm)
- progressive mechanical obstruction
- increases myocardial oxygen demand or decreased supply (tachycardia or anemia)
unstable angina has what changes in lab values and/or ECG
- NO elevation of CK-MB or troponin
- may be ST depression or T wave inversion on ECG
non-ST elevation MI has what changes in lab values and/or ECG
- definite elevation of CK-MB and/or troponin
- ECG:
- typically no ST elevation
- may be ST depression or T wave inversion
unstable angina and NSTEMI treatment
- MONA: morphine, oxygen, nitroglycerin and aspirin
- beta-blockers: metroprolol or esmolol
- antiplatelet: clopidogrel
- anticoagulation with heparin
- statins
-
revascularization if needed
- PCI or CABG
1/5 patients with STEMI will die prehospital due to
V-Fib arrest
what is the most common cause of STEMI
- rupture of a vulnerable plaque in the setting of atherosclerotic coronary artery disease
- results in complete occlusion of artery
in 50% of patients with STEMI, there is an indentifiable precipitating factor such as
- vigorous exercise
- emotional stress
- medical or surgical illness
- within a few hours of awakening in the am
differential diagnosis with chest pain
- CV
- aortic dissection
- pericarditis
- pulmonary
- PE
- pneumothorax
- PNA
- GI
- GERD
- peptic ulcer disease
- chest wall
- costrochondritis
- psychiatry
- anxiety
- cocaine
diagnostic approach to suspected ACS
- 12-lead ECG
- cardiac markers
- cardiac imaging
- angiogram
what is the diagnosis: ST segment elevation with (-) markers
unstable angina
what is the diagnosis: ST segment elevation with (+) markers
STEMI
what is the diagnosis: No ST segment elevation with (+) markers
NSTEMI
what is the diagnosis: No ST segment elevation with (-) markers
unstable angina
what risk score can be used to determine risk of death or serious ischemic events for UA/NSTEMI
TIMI (thrombolysis in myocardial infarction)
TIMI variables for risk stratification. 1 point is given for each of the following factors
- > or = 65
- > or = 3 risk factors for CHD
- prior coronary stenosis > or = 50%
- ST segment deviation
- > or = 2 anginal episodes in prior 24 hours
- increases serum cardiac biomarkers
- aspirin use in prior 7 days
Managment of acute coronary syndrome (MONA)
- morphine
- nitroglycerine
- oxygen
- aspirin, clopidogrel
two main approaches for revascularization post STEMI
- pharmacologically with thrombolytic tx
- percutaneous coronary intervention
- angioplasty or stenting
what are the absolute contraindications for thrombolytic therapy
- hx of cerebrovascular hermorrhage
- hx stroke in past year
- poorly controlled HTN
- systolic > 180, diastolic > 110
- suspected aortic dissection
- active internal bleeding
what is the leading cause of inpatient death post MI
pump failure
