PowerPoint 2 Flashcards
What is a gold standard test?
Test with highest accuracy
Sensitivity of a test?
How often test shows abnormality in population with disease accurately.
Specificity of a test?
How often test does not show abnormality in population without disease
Four-step process in diagnosing heart disease?
-Initial medical history and physical exam
-Align with recommendations of the American College of Cardiology(ACC) and the American Heart Association (AHA)
-Assess patient with noninvasive and invasive tests
-Diagnosis is highly evidence based, providing sufficient information while containing costs
AHA decision tree eight steps?
-Contraindication to Stress testing?
No
-Symptoms or clinical findings warranting Angiography?
No
-Pt. able to Exercise
Yes
-Previous Coronary revascularization
No
-Resting ECG interpretable?
Yes
-Perform Exercise test
Choose test appropriately
-Test results suggest high risk?
No –> diagnosis Yes –> angiography
-Adequate info on DX and Prognosis available?
Yes
When is an exercise test performed as an initial diagnostic tool?
Patient has chest pain, can exercise, and normal resting ECG
What six things are looked for in an exercise test?
CAD
Fitness level
Pathology of dyspnea
What does exercise do to your body?
Return to work test
Gives insight on severity of disease(s)
How safe are exercise tests?
-Generally safe, if prescreening is done properly
-1/2500 tests experience MI or Death
What is the most popular types of exercise test protocol?
Bruce or modified bruce
Exercise tests should not be longer than ____-____ minutes?
12-14
What is an echocardiogram?
Visual inspection of the anatomy
Ability to capture images in various stages of cardiac cycle
What does an exercising echo do?
Compares images at rest and immediately post-exercise
Normal response to exercise-exercise echo?
Augmentation of the left ventricular wall.
Increased ejection fraction and left ventricular size.
Ischemic heart response to exercise-exercise echo?
Normal LV wall motion at rest.
Hypokinesis of LV wall when >70% artery stenosis
MI pts show no changes in ____ ____ wall at ____ or with ____?
MI pts show no changes in LV wall at rest or with exercise
Echo’s improve confidence level for Ischemia in heart from ~ ____ (standard exercise stress test) to ____-____%.
Echo’s improve confidence level for Ischemia in heart from ~ 75% (standard exercise stress test) to 80–85%.
Appropriate candidates for echocardiography?
-Intermediate pretest probability of coronary artery disease and uninterpretable rest ECG.
-Previous revascularization.
Who has a high probability of false-positive exercise test?
Women and patients with concurrent valvular or primary myocardial disease.
Inappropriate candidates for exercise echocardiography?
Multiple myocardial infarctions
Complex wall motion abnormalities
Obese and COPD
Inadequate ambulation (pharmacologic test possible alternative)
When to use pharmacologic echocardiography?
When exercise is contraindicated
What drug is used in pharmacologic echocardiography?
Dobutamine
What is myocardial perfusion imaging?
When radioisotopes are injected near peak exercise.
-Compare myocardial uptake immediately post exercise versus rest.
When is myocardial perfusion imaging indicated?
Follow-up to abnormal resting ECG.
Patients taking digitalis.
Women.
Angiographic-documented CAD.
When is myocardial perfusion imaging selected?
Uninterpretable resting ECG
Unable to reach high HR or SBP during exercise
Moderate/high risk symptoms in Pt
History of bypass surgery
Referred for echo but poor echo images
When is myocardial perfusion imaging contraindicated?
Risk with exercise
Hx of Bronchospasm with vasodilation drugs.
What is the gold standard for assessing CAD?
Coronary angiography
What is coronary angiography?
Cardiac catheterization (gold standard)
Dye injected to highlight arteries during X-ray
Displays limited flow at lumen stenosis or blockages
How is ischemia determined in coronary angiography?
-Coronary artery lumen restriction (lesion) > 70% = ischemia.
-Lesions between 50% and 70% of lumen diameter = borderline.
-Lesions < 50% stenosed; not generally thought to cause ischemia.
What might intravascular ultrasound be beneficial in?
-Identify lesions requiring revascularization.
-Evaluate vessel patency and stent operation.
-Determine amount of obstruction from individual plaque, when Doppler is used in conjunction with IVUS.
What is PCI?
Percutaneous coronary intervetions
What are two PCI?
AKA coronary angioplasty
Noninvasive surgical procedure using balloon to reestablish normal blood flow in affected coronary arteries.
High (25–50%) rate of restenosis within the initial 6 months without stent.
Drug eluting stent (DES) restenosis rate ~23%.
What is CABG?
Coronary artery bypass graft surgery
Reasons to perfrom CABG?
-Stable or unstable angina.
-Multiple stenosed coronary arteries and/or the left main coronary artery.
-Significant future cardiac event risk.
-Postmyocardial infarction when blood flow cannot be reestablished via PCI.
What is a PET scan?
Position emission tomography
Highly accurate noninvasive method of identification and assessment of severity of CAD.
What does a Cardiac MRI provide?
Provides anatomic view of heart in order to:
Assess extent of damage to left ventricle and type of cardiomyopathy.
Visualize the pericardium and coronary arteries.
Evaluate thoracic aorta and valvular function in congenital heart disease.
What is coronary calcium scoring?
Noninvasive using electron beam computed tomography (EBCT) or spiral tomography (CT).
Quantifies calcium in coronary arteries.
Related to the development of atherosclerosis.
Sensitivity ~92%, specificity ~51% for occlusive disease.
Effective for identifying preclinical, nonocclusive disease.
What is TWA?
T wave alternans testing
Screen and risk stratify individuals for risk of sudden cardiac death.
Software assessment of beat-to-beat variability in timing intervals and shape of T waves.
In what population is TWA applicable?
Previous myocardial infarction.
Reduced left ventricular ejection fraction.
Symptomatic heart failure.
Three methods for calculating heart rate?
Dark line method
1500 method
6 second method
Dark line method?
Regular HR
1st R-wave on dark line
Measure distance to next dark line
R waves on every dark line = 300 bpm.
Every other dark line = 150, every third dark line = 100, 75, 60, 50
1500 method?
Count # of small boxes between R waves
Divide 1500 by # of small boxes to get bpm
6-second method?
Irregular HR
Determine 6 sec period or 30 large boxes
Count the cardiac cycles in 6 sec period then multiply by 10 to get bpm
How to prepare for ECG placement?
-Can be tricky, Electrodes need to be sticky
-Often need to rub off dead skin cells and wipe clean with alcohol prep pad
What does noise in the ECG mean?
Weak signals
What are the two categories of leads?
6 Limb and 6 precordial/chest leads
What are the 6 limb leads?
3 bipolar
R Arm, L Arm, R Leg, L Leg
3 unipolar
aVF, aVL, aVR
What are the 6 precordial leads?
V1-V6
Lead I?
Lead I = LA – RA (flow RA –> LA)
Positive deflection
Lead II?
Lead II = LL – RA (flow RA –> LL)
Most positive deflection
Most aligned with Heart axis
Commonly used to Record HR
Lead III?
Lead III = LL – LA (flow LA –> LL)
Positive deflection
Einthoven’s triangle?
Einthoven’s Triangle shows movement of electrical activity from Neg to Pos poles as compared to the heart and defined Bipolar limb leads
RL electrode function?
RL Electrodes serve as a ground. No electrical movement.
What are the unipolar limb leads?
Augmented vector lead/combo leads
Uses RA, LA or LL as Pos pole and then combined signal of the two others as Neg pole. Augmenting signal strength for measuring Electrical activity
aVF?
Augmented Vector Foot Lead
aVL?
Augmented Vector L Arm Lead
aVR?
Augmented Vector R Arm Lead
QRS complex shows Neg deflection. Opposite of Lead II.
V1 electrical activity captured and placement?
R side of septum
4th intercostal R of sternum
V2 electrical activity captured and placement?
Anterior side of heart and septum
4th intercostal L of sternum
V3 electrical activity captured and placement?
Anterior region
Mid point btwn V2 and V4
V4 electrical activity captured and placement?
Anterior region
5th intercostal space Mid clavicular line
V5 electrical activity captured and placement?
Lateral region
Level with V4, Ant axillary line
V6 electrical activity captured and placement?
Lateral region
Level with V4, mid axillary line
Direction of normal sinus rhythm?
Depolarization is downward and to the left
Same as Lead II and with normal axis deviation
Eight normal components of the cardiac cycle?
-1 P wave before every QRS complex
-P wave and QRS complex positive in Lead II
-P wave and QRS complex negative in aVR
Intervals within normal limits
-PR interval 0.12 – 0.20 sec
-QRS complex < 0.10 sec
-HR 60-99 Bpm
-Normal Axis Deviation present
-All waveforms must have normal morphology for leads observed and be identical in every cycle.
What is the P Wave?
1st positive deflection in ECG (except aVR)
Generated by atrial depolarization
Representing electrical activity from SA node to AV node
P wave happens right before atrial depolarization
(starting of Atrial systole progressing to Atrial kick)
Atrial kick allows for Ventricular top off of blood volume
P wave appearance?
Positive in lead II and Neg in aVR
If Opposite, (Neg Lead II, Pos aVR) the rhythm originated outside of the SA Node
Abnormal morphology could mean various chamber enlargement
Normal P wave
Height = < 2.5mm
Length = < .10sec
PR interval should be within 1 small box. Representing atrial rate.
What is the PR interval?
Measured from beginning of P wave to Beginning of QRS Complex
Time btwn beginning of Atrial depolarization to beginning of Ventricular depolarization
NOT just time needed for Atrial Depolarization
Appearance of PR interval?
Normal PRI is 0.12 – 0.20 sec
Premature Beats or beat from above AV junction is < 0.12
Conduction disturbances of impulses show > 0.20 sec
What is the QRS complex?
LV electrically dominate
Time for complete V Depolarization
Appearance of QRS interval?
Normal time 0.06 - 0.10sec (1.5-2.5 sm boxes)
ST segement?
End of S wave start of T wave
No electrical activity in heart
Myocardial contraction occurring
Ventricles emptying
Should be isoelectric or baseline
ST elevation signal?
Evidence of recent or upcoming MI
Sign of myocardium needing O2 and nutrients
Should be seen in reciprocal leads
Seen in exercise means PROBLEMS!
ST depression signal?
Evidence of CAD or old MI injuries
Electrical signal taking longer to travel
During exercise shows myocardial Ischemia
Ventricular Hypertrophies and branch bundle blocks
What is the T wave?
Ventricular Repolarization and end of Ventricular systole
“End of Systole, Start of Diastole”
Post T wave heart relaxes
T wave has a positive deflection
Normal T-wave shape?
Normal Asymmetrical shape
-Up slow, down fast
What does a symmetrical T wave indicate?
Symmetrical wave means pathology
What does a peaked T wave mean?
Hyperkalemia
What does an inverted T wave mean?
Coronary ischemia, LV hypertorphy
U wave?
Last small, rounded, upward deflection in Lead II
Last stage of ventricular repolarization
Not usually seen on Normal ECG
Can be fused with T wave
How long should Q-T interval be?
Normal QTc < 0.44 sec and less than half of R-R interval.
What do enlongated Q-T intervals mean?
Increased risk for sudden death
