Cardiology Flashcards
(146 cards)
> Rapid rule-out protocols for ACS are now well-accepted
-ADAPT (incorporates TIMI score)
-HEART
-EDACS
These stratify patients to low enough risk to justify discharge for further outpatient evaluation
For intermediate risk patients (e.g. HEART score 4-6), admit/obs, get stress test or CCTA
For higher risk patients, admit for full workup and potential aggressive therapy
Chest Pain Evaluation
- Spectrum of disease due to myocardial ischemia
- Unstable angina to acute MI - Ischemic heart disease is the most common cause of death in the US
- 2 million MI and unstable angina patients each year
Acute Coronary Syndrome (ACS)
Usually due to atherosclerosis
Fixed lesion, critical stenosis
Plaque disruption, platelet aggregation, thrombus formation
Results in oxygen supply/demand imbalance leading to cardiac muscle damage
Causes of ACS
Trauma Connective tissue diseases (vasculitis) Metabolic diseases (thickening of vessels) Congenital anomalies Thrombus (DIC, TTP) Emboli (bacterial, non-bacterial) Thoracic aortic dissection Coronary artery dissection Drugs (cocaine) Infectious diseases
Non-Atherosclerotic Causes of ACS
4% of AMIs have normal EKG
Hyperacute T waves (early)
ST segment changes
1mm of elevation in two anatomically
contiguous leads
Elevation usually corresponds to areas of
involvement
Exception: AMI with LBBB
Depression over areas opposite injury
(reciprocal changes). Predictor of larger
MI, increased mortality
T wave inversion: within 4 hours is good
Px sign
Significant Q waves: 1 square wide, 1/3 of
height of R wave
AMI EKG Changes
Differential diagnosis of diffuse STE Acute MI (large one!) Prinzmetal's angina (vasospasm) Pericarditis Ventricular wall aneurysm Benign early repolarization
EKG - ST Elevation
Factors that increase the specificity
ST elevation (horizontal or convex upwards)
Follows coronary anatomy
Reciprocal ST depression
Changes over time (minutes to hours)
May see hyperacute T waves (early)
Q waves (start developing within a few hours)
ST Segment ElevationPredictors of MI
Convex or concave upwards morphology Transient over minutes More common in women Difficult to distinguish from true STEMI Generally underlying CAD is present Usually no reciprocal depression
Causes of ST Segment Elevation:Prinzmetal’s angina/spasm
Convex or concave upwards morphology Persistent ST elevation Large Q waves usually present Usually in anterior leads Easily seen on echo No reciprocal depression Look for old ECGs — no change No serial changes
Causes of ST Segment Elevation:Ventricular Aneurysm
Concave upwards morphology In many leads, maximal in mid-precordial leads with “fishhook” J-point Doesn't change over time No reciprocal depression Men > women, young > old No large Qs
Causes of ST Segment Elevation: “Early Repolarization”
Posterior MI
Usually accompanies inferior MI due to RCA…
But 4-10% will be isolated posterior MI
Look for large R waves with ST depressions in V1, V2 and upright Ts
R:S > 1 = “large R waves”
STEMI and STEMI EquivalentsPMI: ST-depression + tall R-waves in V1-2
EKG indications for emergent reperfusion
STE > 1 mm in 2 contiguous leads
Posterior MI (ST-depression with tall R-
waves and upright Ts in V1-2)
Left bundle branch block with
concordant Sgarbossa criteria
ST-segment elevation measuring ≥1
mm concordant with the QRS in any
lead.
ST-segment depression measuring
≥1 mm in any of the V1 through V3
leads (concordant with the QRS).
A RBBB should not obscure the diagnosis
of an acute MI
STEMI and STEMI Equivalents
Predictors of reperfusion
Normalization of ischemia-related ST elevation
Failure to normalize may indicate the need for “rescue PCI”
Early T wave inversions can be highly specific markers of reperfusion
An accelerated idioventricular rhythm (rate 60-120) is also highly specific for reperfusion
Benign, don’t suppress it
Resolves within seconds to minutes
The EKG in AMI
1-2 hours (rises)
4-6 hours (peaks)
24 hrs (normalizes)
Myoglobin
3-6 hours (rises)
12-24 hours (peaks)
7-10 days (normalizes)
Troponin
3-4 hours (rises)
12-24 hours (peaks)
1-2 days (normalizes)
CK-MB
Advantage: early detection
Disadvantage: poor specificity, especially in trauma, renal failure, hemolytic syndromes
Myoglobin
more specific for AMI than CK-MB
High values predict complications and mortality
Troponin
Elevation without infarction (skeletal disease, muscle exertion, cocaine, renal failure)
Comparing MB to total CK improves specificity
CK-MB
Oxygen Nitrates (sublingual, topical, IV) Contraindicated if sildanefil (Viagra) etc. within 24 hours or if hypotensive Caution/avoid in RV MI Vasodilatation ASA (162-325 mg) ASA alone reduces mortality 23% Combined with thrombolytics, ASA reduces mortality 42% Morphine for persistent pain
Therapy of AMI
Heparin (Unfractionated or LMWH)
Beta blockers – early IV use is discouraged
Give within 24 hours orally but no rush
Contraindications (asthma, CHF, bradycardia, hypotension; caution in RV MI)
Addl. platelet inhibitors (in ED or cath lab)
GP Ilb/IIIa receptor antags IV
Clopidogrel, ticagrelor: can give oral load
Prasugrel 60 mg oral load at cath; avoid if history of TIA or stroke
Therapy of AMI
Thrombolysis vs. percutaneous coronary intervention
Outcomes have shown consistent benefit with PCI over thrombolytics
Guidelines recommend PCI if balloon inflation can be performed within 90 minutes
Window of benefit over lytics extended if chest pain > 6 hours or if cardiogenic shock
Therapy of AMI
Concerning Sx’s greater than 30 minutes but less than 12 hours, not relieved by nitroglycerin
EKG criteria of STEMI as previously discussed
STE in 2 contiguous leads
Posterior STEMI
[LBBB with Sgarbossa concordant criteria for EM boards]
PCI delayed greater than 90-120 minutes
Thrombolytic Therapy Indications
Absolute
PCI immediately available
Active bleeding from any site
CVA within 6 months or hemorrhagic CVA at any time in the past
Intracranial or intraspinal surgery or trauma within 2 months
Intracranial or intraspinal neoplasm, aneurysm or AV malformation
Suspected aortic dissection
Contraindications to Thrombolytic Therapy