PMT, Johnstons - MI (STEMI, NSTEMI) Flashcards
What are the cardinal symptoms of CVDisease?
- Chest pain/discomfort
- Dyspnea, orthopnea, paroxysmal, nocturnal dyspnea, wheezing
- Cough, hemoptysis
- Fatigue, weakness
- Pain in extremities with exertion (claudication)
STEMI means what?
ST segment Elevation
“Transmural” - involves entire wall with complete interruption of blood flow.
CHD occurs in how many adults?
1/6
Pathobiology of MI
Most MIs are caused by atherosclerosis and rupturing of the plaque.
- STEMI = coronary flow occluded
- NSTEMI or UA = partial coronary occlusion
S/S of MI
- Chest discomfort (more severe than angina)»_space; “heavy, crushing”
- Retrosternal, left, across chest, neck, jaw, left arm, epigastrum
- N/V. Diaphoresis, dyspnea.
- Cannot be relieved by nitro or rest
- 20% are painless»_space; diabetics and elderly!
PE of MI
- May be normal
- S4
- S/S of HF = (S3, crackle, JVD, new murmur)
- BP and HR dependent on location of infarct**
BP and HR in anterior wall infarct v. inferior wall infarct.
Anterior wall infarct (LAD) results in increased sympathetic tone = inc. BP/HR
Inferior wall infarct (RCA) results in decreased vagal/PS tone = dec. BP/HR
What is J point?
Where QRS stops and ST begins.
STEMI on ECG
**ST elevation of 2mm or more in 2 or more contiguous chest or limb leads.
(May be obscured in LBBB.)
Difference in ECG and s/s of NSTEMI v. NSTEMI ACS
Both have: ST depression, T inversion, and chest pain.
NSTEMI has elevated cardiac enzymes, meaning YES, MI.
NSTEMI ACS does NOT have elevated cardiac enzymes, meaning NO MI.
Other than MI, what are causes of ST elevation?
- Pericarditis
- LVH with J point elevation
- Normal variant early repolarization (i.e. young, healthy athlete or young blacks)
Describe ECG evolution in STEMI
Early Acute Phase - T wave amplitude increases; hyperacute pattern; convex upward ST pattern.
Evolved Acute Phase (Chronic Phase) - Resolution of ST elevation variable.
In Evolved Acute Phase (Chronic Phase), resolution of ST elevation variable - this is dependent upon what?
If after two weeks there is still persistent elevation, think what?
- Dependent upon location - 2 weeks for inferior wall infarct. Later for anterior wall.
- Ventricular aneurysm
Normal QRS duration. Normal Q wave duration. Normal QT* duration. Normal ST Normal T
- QRS is 0.05-0.10 sec
- Q wave is less than 0.03 sec
- ST is NEVER normally depressed (, but can be elevated in standard (1mm) and chest (2mm) leads
- Normal QT is 0.40sec (Fatal if prolonged)
- T is postive in L1, L2, V3-V6 (not greater than 5mm in standard, 10mm in chest). Is inverted in AVR.
ST depression means what?
Subendocardial injury. No Q wave.
ST elevation means what?
Subepicardial or transmural injury.
Myocardial ischemia to injury to infarction is indicated by what zones of infarction on ECG?
1) Ischemia - T wave inversion - due to deficient blood supply affecting repolarization
2) Injury - ST segment elevation - shifts (deficient blood supply)
3) Infarction - large Q waves - due to dead tissue causing absence of deloparization current. T waves inverted
Localization of MI/Myocardial ischemia
- LAD is anterior wall ischemia, seen on V1-V6
- RCA is inferior wall ischemia, seen on L2, L3, AVF
- LCX is lateral wall ischemia, seen on L1, AVL
Tombstone T waves indicate what?
Infarction
What do you see on an ECG in a posterior wall infarction?
Reciprocal of anterior wall:
V’s: unusually large R and upright T
Labs in MI
- Inc. WBC 12k-15k (hrs to 2-4 days)
- Inc. CRP
- Inc. BNP
Cardiac biomarkers of necrosis.
What can cause false positives?
Troponin.
Renal failure.
What are non-MI causes of elevated troponin?
CV, pulmonary (pulm embolism, HTN) , neurological (IC-hemorrhage, stroke), shock, renal
Most deaths from aMI are due to what?
VFib
Tx of STEMI and time frame.
What is DIDO and time frame?
- Reperfusion with PCI in Cath Lab within 90 minutes (transfer within 120min if hospital does not have cath lab)
- Fibrinolysis within 30 minutes
- “Door In, Door Out” within 30 min if non-PCI-capable hospital
Failure of ST elevation to resolve by __% in __hrs suggests failure of fibrinolysis.
50% in 1-2hrs
When is PCI preferred and what are its advantages?
- Preferred with STEMI within 12 hours of s/s onset.
- Lowers mortality rate and ICH
What two things are PCI useful for and what is its major disadvantage?
- Useful for STEMI, new LBBB, within 12 hours of s/s onset.
- Major risk of ICH
Contraindications of fibrinolytic therapy.
Are menses contraindicated?
- Active bleed or bleed tendency. (**Menses excluded!)
- Prior hemorrhagic stroke, ischemic stroke within 3 months, except acute ischemic stroke within 3-4.5hrs
- Intracranial or spinal cord neoplasm or AV malformation
- Suspected or known aortic dissection
- Closed head or facial trauma within 3 months
What is the initial pharmacological management of a STEMI
- **ASA - given upon presentation
- **IV Heparin or Enoxaprin (ADP-receptor inhibitor or Antiplatelet agent - clopidogrel; use for once year after PC1 for STEMI with stenting to prevent stent stenosis)
- **Nitroglycerin
- **Morphine
- BB
- Oxygen
- Stool Softener
- ACE
When do you NOT give BB to a STEMI?
When the patient is decompensated»_space; dec. HR, BP, MVO2.
Don’t use anything higher than 1st degree AVB.
“hurts to breath, but feels better leaning forward” is what? A complication, post-MI, is what and tx?
Acute pericarditis 2-4 days post MI. If 2-10 weeks after MI could be Dressler.
Rx - ASA and NSAID
What rhythm disturbances do you get post MI?
- VT, VF
- Accelerated Idioventricular Rhythm (AIVR)
- AFib (5-10% of aMI)
- Sinus brady - inferior MI
- Wenckebach - inferior MI
What is AIVR and when does it occur?
- After fibrinolytic therapy as reperfusion occurs.
- SLOW, but looks like vtach (60-100BPM)
- BENIGN
What is the leading cause of death in hospital from aMI?
HF due to LV dysfunction (S3, S4 crackles), RV infarct (inferior STEMI), cardiogenic shock
Kaussmaul sign indicates what?
JVD - RV infarct.
What mechanical complications can occur after an inferior wall-MI? What indicates this? Tx?
- MR due to Infarction of papillary muscles
- NEW holosystolic murmur associated with inferior wall MI
- Sinus brady
- Wenckebach
Tx - surgery
What mechanical complications can occur after an anterior wall-MI? What indicates this? Tx?
- Septal rupture with VSD.
- LV free wall rupture - causes tamponade
- LV aneurysm - associated with anterior MI
Rx - surgery
What leads can dx RV infarction due to proximal occlusion of RCA before acute marginal branch?
R precordial, ST elevation of 1+mm in V4-V6R
Pericarditis, myocarditis, Takotsubo, Early repolarization
**DDx of STEMI?
- Pericarditis
- Myocarditis
- Takutsubo (ST elevation, coronaries normal)
- Early ventricular repolarization (blacks)
Anterior MI:
- LV free wall rupture - causes what?
- LV aneurysm - associated with what?
Tamponade
anterior MI
