Cardiology : Diagnostic Modalities Flashcards
Indications for 12-Lead EKG
acute CP
current palpitations
LV Hypertrophy screening
evaluation of past MI
Contraindications for 12-Lead EKG
None
Indications for telemetry
hospital admission for CP or possible ACS
12 Lead EKG works by detecting ________ in the heart.
electrical activity
What is important when administering 12 lead EKG?
serial collection of data.
don’t use as a solitary assessment
Which cardiac enzyme test is preferred to diagnose and provide prognosis of MI?
high-sensitivity cardiac troponin
Is cTn I or cTn T more sensitive for cardiac infarct?
cTn I
troponin is considered a biomarker of what
cardiac injury
When should you expect to see elevated troponin and CK-MB?
trauma, surgery, inflammation, infection
what is an important consideration when evaluating both EKG and troponin?
must obtain serial enzymes and several EKGs to compare against baseline.
On serial cardiac enzymes, what is indicative of acute ischemia?
rise and fall of troponin
CK and troponin both have an onset of 3-12 hrs and a peak at 18-24, but troponin has a duration of ______ while CK’s duration is ______.
Troponin duration: 14 days
CK: 36-48 hrs
This is the primary noninvasive modality for quantitative and qualitative evaluation of cardiac anatomy and function….
transthoracic echocardiogram (TTE)
What are the indications for TTE?
evaluate wall motion, valve structure and function
calculate EF
This imaging modality can detect:
LA clots within the heart
valvular pathology
visualization of vegetations in endocarditis
transesophageal echo (TEE)
Who must be present when performing TEE?
cardiology and anesthesiology
TEE provides high resolution of what cardiac structures?
posterior cardiac structures
What are the indications for cardiac stress tests?
exertional chest pain
CHD with new/worsening symptoms
Newly diagnosed CHF or cardiomyopathy
What are the contraindications for cardiac stress testing?
acute MI in 48 hours
unstable angina
uncontrolled arrhythmia, heart failure, hypertension
acute aortic dissection
severe pulmonary HTN
acutely ill
This cardiac stress test is:
- Less expensive
- helps diagnose CAD in symptomatic patients
- Useful in assessing functional capacity
Exercise EKG
What should a clinician look for during exercise EKG stress test?
EKG changes from baseline
Increased HR
Development of Sx
What is the protocol for an EKG stress test?
- baseline resting EKG
- exercise to target HR, Sx, or time
- monitor Sx and EKG
This cardiac stress test has the following advantages:
low cost
no radiation
determines exercise capacity
widely available
mimics physiological conditions
Exercise EKG
This cardiac stress test has the following disadvantages:
Doesn’t localize ischemia
doesn’t evaluate LV function
Lower sensitivity
Poor specificity in ST-T abnormal pts, digoxin use, LBBB or pacemakers, female population
exercise EKG
What radioactive tracers are used for the nuclear stress test? Where do these concentrate?
Technitium-99m or Thallium
concentrate in myocardium with adequate blood flow
Does a nuclear stress test utilize exercise or pharmacologic stressors?
pharmacologic
What drugs are used in nuclear stress testing to cause cardiac stress?
Vasodilators: adenosine, dypyridamole
What causes more dilation and by what degree: Exercise or pharmacologic intervention?
pharmacologic intervention by 3-5x
Nuclear Stress Test Protocol:
Inject tracer
wait 20-40 mins
Scan at rest
Induce stress w/ adenosine/dypyridamole to achieve target HR/Sx
Inject tracer 2nd time
wait 20-40 min
2nd Scan
Compare scans
With a nuclear stress test, reversible ischemia would be found with what results?
good perfusion at rest, ischemia under stress
With a nuclear stress test, non-reversible ischemia (infarction) would be found with what results?
ischemia at rest and during stress
This cardiac stress test has the following indications:
abnormal resting EKG
To asses areas of myocardial ischemia
to determine location and size of injured muscle after MI
Dx coronary artery stenosis
evaluate function of grafted vessels after bypass
Nuclear stress test
This cardiac stress test has the following indications:
known or suspected CAD
evaluation of CP, SOB, DOE
Evaluation of valvular abnormalities
preop risk assessment
stress echo
Which drug is used to cause stress in a stress echo?
dobutamine
This stress test can evaluate ischemia related to wall motion abnormalities when stressed
stress echo
When should a stress echo be avoided?
afib and LBBB
What is the protocol for a stress echo?
TTE at rest
administer dobutamine
reach target HR, administer stress echo
compare baseline and stress images
When wearing a Holter Monitor, a patient’s cardiac electrical events are recorded over ________
24-48 hours
What are the indications for a Holter Monitor?
syncope, palpitations
What is a major limitation of Holter Monitor?
79% of patients are asymptomatic during the 24-48 hour period
How long can an event monitor be worn?
30-60 days
What is a major difference between an event monitor and a holter monitor?
Holter is continuously recording
How does a patient record a cardiac event when wearing an event monitor?
patient pushes button to capture previous 2-5 minutes to present.
For how long does an implantable cardiac monitor record?
3 years
What activates an implantable cardiac monitor?
automatically activated, or patient activated
indictions for implantable cardiac monitor?
infrequent sxs
suspected arrhythmia with inconclusive non-invasive testing
What is a fingertip monitor used for?
monitoring afib and other symptomatic arrhythmias
What are the two main forms of cardiac CT?
coronary CT angiography
coronary CT calcium scan
This cardiac imaging modality:
assesses presence and extent of coronary artery occlusion
given with contrast
CCTA
This cardiac imaging modality:
assesses for calcium deposits in coronary arteries/MI risk
Given without contrast
Coronary CT calcium scan
This imaging modality is the following major applications:
detection of aortic dissection
detection of coronary artery calcium deposition/atherosclerosis
detection for presence and extend of CAD
Cardiac Computerized Tomography
The indications for cardiac CT scan:
Aortic dissection
stable angina
r/o CAD
What are the contraindications for cardiac CT scan?
allergy to contrast dye
severe renal insufficiency
This imaging modality has the following characteristics:
assessment of functional and tissue properties of heart
highlights atrial and ventricular anatomy
highlights myocardial tissue composition
Cardiac MRI
Cardiac MRI is typically used for what patients?
complicated patients after 1st line testing/echo
Indications for cardiac MRI:
myocardial, pericardial, or valvular disease
cardiac tumor
CAD
myocardial perfusion
What are the contraindications for cardiac MRI?
metal or electrical implants, devices or foreign bodies
What is the gold standard to diagnose CAD, but is often not 1st line test?
cardiac catheterization/coronary angiography
What is the protocol for cardiac catheterization?
Thread catheter through groin, arm, neck
inject radiopaque dye
view patency of coronary arteries via fluoroscopy
What risks accompany cardiac catheterization?
bleeding, arrythmia, vessel injury
Indications for cardiac catheterization?
known/suspected CAD
Atypical chest pain
before valve surgery in CP patients
What conditions would make you suspect CAD, and therefore order cardiac cath?
unstable angina
angina and (+) exercise stress test
history of MI w/ EKG changes
post-resus from cardiac arrest
What are two methods of percutaneous coronary intervention?
balloon angioplasty
cardiac stenting
