Coronary Artery Disease Flashcards
What are the inferior, anterior, and lateral leads and which blood vessels supply those areas?
II, III, aVF - supplied by RCA
V1-V4 - supplied by LAD
I, aVL, V5-V6 - supplied by circumflex
What can a new LBBB in a patient presenting with chest pain be suspicious for?
STEMI
Of the acute coronary syndromes, which are more common?
NSTEMI and unstable angina more common than STEMI
Where is a plaque particularly vulnerable to rupture?
The shoulder
When during the day is acute MI most likely to occur?
Between 6am and noon
Peak incidence in first three hours after awakening
What’s the main goal of treatment for patients presenting with a STEMI?
Achieve reperfusion within 120 minutes - optimally within 60
What are the options for reperfusion in a STEMI?
PCI - primary coronary intervention - door to balloon time of less than 90 minutes
Thrombolytic therapy - door to needle time within 30 minutes
What are absolute contraindications to thrombolytic therapy?
Active internal bleeding
Recent (<1 mo) GI bleeding
Recent serious trauma, including prolonged CPR
What are relative contraindications to thrombolytic therapy?
Severe hypertension (s>200, d>110) Recent minor trauma Hemostatic defect Severe hepatic or renal disease Diabetic hemorrhagic retinopathy
What are 3 major factors to consider when crossing between PCI and thrombolytic therapy?
Availability of PCI capable lab that can achieve door to balloon of 90 minutes - if not, thrombolytic, then transfer later
Bleeding risk or contraindications for thrombolytic - use PCI
experience of operator doing PCI
What are acute medications commonly given after MI?
Aspirin Other antiplatelet agents (clopidogrel) Heparin Nitrates Beta blockers - but can precipitate cardiogenic shock in tachycardia, heart failures or large infarctions - don't use ACE inhibitors - if normal creatinine and not hypotension Statins Admin of oxygen
Which two drugs have been proven in long term studies to reduce mortality following MIs?
Beta blockers
Captopril (ACE inhibitor)
What is the pathophysiology of NSTEMI or unstable angina?
Periodic platelet plugging and platelet mediated coronary arterial vasoconstriction occur after which portions of plug break off and are swept away, partially restoring perfusion
What is the medical therapy for NSTEMI and unstable angina?
Reperfusion with thrombolytics not beneficial
Emergent coronary intervention not required
Invasive management reduces morbidity but not mortality and is warranted if: older than 65, marked ST and T alterations, enzyme evidence of myocyte necrosis –> angiography followed by revascularization (catheter based or surgical)
Also indicated if patient has spontaneous or inducible ischemia despite adequate medical therapy
In addition to coronary revascularization, what does therapy of unstable angina or NSTEMI center on?
Platelet inhibition (clopidogrel, aspirin) Thrombin inhibition (LMWH) Control of oxygen demands (beta blocker) Prevention of vasoconstriction (nitroglycerin)
What cocktail are patients who have been diagnosed with NSTEMI or unstable angina given when discharged from the hospital?
Aspirin Clopidogrel Beta blocker ACE inhibitor Statin
What 3 factors determine long term prognosis following acute MI?
Patient age
Residual left systolic function
Extent and severity of underlying coronary artery disease
What irregular ventricular rates are common after an acute MI and how are they treated?
Ventricular premature beats common 2-3 days post MI - don’t require therapy but monitor in case turns into VT or VF
Prophylactic therapy with antiarrhythmics not used
VT/VF within 24 hrs after acute MI not associated with adverse prognosis
Other than ventricular rates, what other abnormality is commonly seen after an acute MI and how is it treated?
AV block of some degree
First degree usually with inferior MI - require no therapy, almost always transient, lasting no more than 24-48 hrs, but watch for development of more serious blocks
Type I second degree - inferior - usually transient 2-3 days, no therapy unless ventricular rate too slow, then give atropine
Type II second degree - anterior - often permanent, pacemaker
Third degree - inferior - transient within a few days, no pacemaker
Third degree - anterior - infarct of BBs, permanent pacemaker
What are the kilip classes of left ventricular heart failure following an acute MI?
I - none II - mild III - substantial IV - cardiogenic shock Mortality increases as you go up in class
What are the clinical manifestations of cardiogenic shock?
Hypotension and hypo perfusion of critical organs
Elevated LV filling pressures
Cardiac index depressed
Pulmonary congestion
What are the risk factors for cardiogenic shock?
Severe coronary atherosclerosis (usually in LAD) Prior MI increased age Female gender Diabetes STEMI anterior infarct
What is the treatment of cardiogenic shock?
Agents to support BP and augment ventricular function
Intraaortic balloon pump
PCI or bypass surgery
What are the 3 main MECHANICAL complications of acute MI?
Ventricular septal rupture (ant or inf infarct, 1-5 post MI)
Papillary muscle rupture –> mitral regurgitation (inf infarct, usually posterior leaflet because only LAD, ant has LAD and circumflex, 1-5 days post MI)
Free wall rupture (can lead to SCD, ant or inf infarct)
