Cardiology: Acute Coronary Syndrome

Question 1

how is ACS defined?

Answer 1

spectrum of clinical syndromes caused by plaque disruption or vasospasm that leads to acute myocardial ischemia

Question 2

what is unstable angina defined as?

Answer 2

chest pain that is new onset, accelerating or occurs at rest, distinguished from stable angina pectoris by pt history

Question 3

how is unstable angina different from NSTEMI?

Answer 3

unstable=signals impeding infarction base on plaque instability. no elevation in cardiac enzymes, but ST changes in ECG
NSTEMI=myocaridal necrosis marked by elevations in troponin I and CK-MB without St segment elevations on ECG

Question 4

how are pts with ACS risk stratified?

Answer 4

using Thrombolysis in Myocardial Infarction (TMI)
History: 
Age>65 years
>3CAD risk factors
Known CAD (stenosis >50%)
ASA use in past 7 days
Presentation: 
Severe angina (>2 episodes w/i 24 hrs)
ST deviation >0.5mm
\+cardiac marker
each factor is 1 pnt
>3pnts= higher risk pts

Question 5

how is ACS treated?

Answer 5

same as for stable angina

clopidogrel, unfractionated heparin, enoxaparin

Question 6

what should be given to ACS pts with chest pain refractory to medical therapy, an TIMI score >3 a troponin elevation, or ST changes>1mm

Answer 6

give IV heparin and schedule angiography and possible revascularization (percutaneous coronary intervention PCI or CABG)

Question 7

how is STEMI defined?

Answer 7

ST elevation myocardial infarction is defined as ST-segment elevations and cardiac enzymes secondary to prolonged cardiac ischemia and necrosis

Question 8

how does STEMI present?

Answer 8

acute onset substernal chest pain, commonly described as pressure or tightness that can radiate to left arm, neck or jaw

Question 9

what associated symptoms of STEMI?

Answer 9

diaphoresis, SOB, lightheadedness, anxiety, nausea/vomiting, and syncope

Question 10

what PE findings are associated with STEMI?

Answer 10

arrhythmias, hypotension (cardiogenic shock), and evidence of new CHF

Question 11

what is the best predictor of survival in STEMI?

Answer 11

left ventricular EF

Question 12

what MOAN mnemonic for treatment of MI

Answer 12

Morphine
Oxygen
NItrogen
ASA

Question 13

how is STEMI seen on ECG?

Answer 13

ST segment elevations or new LBBB.

posterior wall infarct=ST segment depression and dominant R waves in leads V1-V2

Question 14

Describe sequence changes in STEMI

Answer 14

peaked T waves, ST segment elevation, Q waves, T wave inversion, ST segment normalization, T wave normalization over several hrs to days

Question 15

what is the most sensitive and specific cardiac enzyme? what other enzymes are checked? when do they rise?

Answer 15

troponin I
CK-MB and CK-MB/total CK ration (CK index)
both can take up to 6hrs to rise following onset of chest pain

Question 16

ST segment elevation in which leads is associated with inferior MI? which arteries are involved? what should be obtained afterwards?

Answer 16

II, III, avF
involves the RCA/PDA and :CA
obtain an right-sided ECG to look for ST elevations in the right ventricle

Question 17

ST segment elevations in which leads is associated with anterior MI? which arteries?

Answer 17

leads V1-V4

involves the LAD and diagonal branches

Question 18

ST segment elevations in which leads points to a lateral MI? which artery?

Answer 18

I, avL, and V5-V6

LCA

Question 19

ST segment depression in leads V1-V2 is associated with? what should be obtained?

Answer 19

acute transmural infarct in posterior wall

obtain posterior ECG leads V7-V9 to assess for ST segment elevations

Question 20

describe typical pattern of serum marker elevation after an acute MI. include myoglobin, CK-MB, LD1, MLC, cTnl, and cTnT

Answer 20

see figure 2.1-9 on pg 33

Question 21

A woman is found with pulseless electrical activity on hospital day 7 after suffering a lateral wall STEMI. The ACLS protocol is initiated. What is the next best step?

Answer 21

this pt has likely suffered a left ventricular free wall rupture with acute cardiac tamponade. emergent pericardiocentesis is the next best therapeutic and diagnostic step

Question 22

what six key medications should be considered in treatment of ACS?

Answer 22

ASA, beta-blockers, clopidogrel, morphine, nitrates, and O2

Question 23

If pt with ACS is in heart failure or cardiogenic shock, do not give what? what should be given instead?

Answer 23

beta-blockers

give ACEIs provided pt is no hypotensive

Question 24

what procedures should be performed in pt with ACS?

Answer 24

emergent angiography and PCI

Question 25

what is the time limit for PCI? what can be given after this?

Answer 25

90 minutes
after this there is no contranindication to thrombolysis,if within 3 hrs of chest pain onset given tPa and thrombolysis, reteplase, or streptokinase

Question 26

what is longterm treatment for ACS?

Answer 26

ASA, ACEIs, beta blockers, high dose statins, and clopidogrel (if PCI was performed)

Question 27

name indications for CABG using mnemonic UnLimiTeD

Answer 27

Unable to perform PCI (diffuse disease)
Left main coronary artery disease
Triple-vessel disease
Depressed ventricular function

Question 28

what is the most common complication following acute MI? what is most frequent cause of death?

Answer 28

arrhythmia

letal arrhythmia

Question 29

name some less common complications following acute MI?

Answer 29

reinfarction, left ventricular wall rupture, VSD, pericarditis, papillary muscle rupture (with MR), left ventricular aneurysm or pseudoaneurysm, and mural thrombi

Question 30

define Dressler’s syndrome? when does it occur? how does it present? (5 symptoms)

Answer 30

autoimmune process, occurs 2-10 weeks post MI, presents with fever, pericarditis, pleural effusion, leukocytosis, and increased ESR

Question 31

describe the timeline of common post-MI complications as follows
first day-1

Answer 31

heart failure

Question 32

describe the timeline of common post-MI complications as follows
2-4 days (2)

Answer 32

arrhythmia, pericarditis

Question 33

describe the timeline of common post-MI complications as follows
5-10 days (5)

Answer 33

left ventricular wall rupture (acute pericardial tamponade causing electrical alternans, pulseless electrical activity), papillary muscle rupture (severe mitral regurgitation)

Question 34

describe the timeline of common post-MI complications as follows
wks-months (6)

Answer 34

ventricular aneurysm (CHF, arrhythmia, persistent St-segment elevation, mitral regurgitation, thrombus formation)