Transcript Cardiac Procedures

Cardiovascular Testing
J.B. Handler, M.D.
Physician Assistant Program
University of New England
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Abbreviations
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PCI- percutaneous coronary
intervention
CHD- coronary heart disease
CABG- coronary artery
bypass surgery
Tc- technetium
CO- cardiac output
SVR- systemic vascular
resistance
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Ambulatory Monitoring
Arrhythmia Detection
 Evaluation of Syncope
 Evaluation of symptoms suggestive
of arrhythmia
 Identifying patients with heart
disease at risk for sudden death
 Evaluation of anti-arrhythmia
therapy
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Ambulatory Monitoring
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AKA “Holtor Monitoring”: 2 ECG
leads are monitored and recorded by
a device (cassette recorder) that
patient wears for extended period of
time. Provides continuous recording
of ECG for 24 hours. Useful for
detection of cardiac arrhythmias and
determination if their presence
correlates with patient symptoms.
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Ambulatory Monitoring
Patient diary of symptoms
 Analysis by both computer and
cardiologist
 Event Recorders: prolonged
monitoring for months or more.
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Useful in identifying rhythms that occur
when patient is experiencing
symptoms- palpitations,
lightheadedness, etc.
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Arrhythmia Detection
Stress Testing: Indications
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Evaluation of patients with chest
discomfort suggestive of angina pectoris
(coronary heart disease).
Assessment of functional capacity in
patients with documented CHD.
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Determine prognosis in high risk subsets.
Screening of high risk individuals with
atypical symptoms.
Assess response to therapy including
meds, PCI and CABG.
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Stress Testing: Indications
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Evaluate patients with recent MI pre
and post discharge.
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Exercise prescription for cardiac
rehabilitation post MI.
Screen patients with cardiac risk
factors and certain occupations
(pilots, bus and truck drivers, police
officers, firemen).
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Physiology of Ischemia
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Coronary blood flow- oxygen to
myocardium.
Exercise increases CO and coronary flow
up to 5x.
Blood flow through obstructed arteries
unable to increase to meet demands:
ischemia to tissue chest
discomfortECG or imaging changes.
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Physiology of Exercise
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Exercise increases CO and coronary blood
flow.
MET: Metabolic equivalents
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1 met: resting O2 consumption=
3.5ml/min/kg.
Method: Treadmill testing most
commonly used. Provides graded
exercise/workloads (METs) and O2
consumption.
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Evaluation of Ischemia
Electrocardiogram alone (Stress
Electrocardiography)
 Nuclear (isotope) imaging + ECG
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Thallium201, Tc99 labeled Sestamibi
Echocardiography (imaging) + ECG
 ECG + imaging improves
sensitivity/specificity
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Options for Stress
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Exercise using motorized treadmills
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Protocols using increasing
speed/elevation reproduce quantifiable
workloads at fixed intervals.
Pharmacologic stress
Adenosine and Dipyridamole
 Dobutamine
 Utilize ECG + imaging
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Goals of Exercise Testing
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Increase heart rate and workload in
incremental, objective fashion.
Endpoints:
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Reproduce symptoms and/or diagnostic
evidence of ischemia (ECG).
Achieve target heart rate: 85-90% of
PMHR if no ischemic changes.
Dangerous arrhythmias
Abnormal hemodynamics: ing BP during
exercise means stop the test!
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Exercise Protocols
Exercise Stress Testing
Images.google.com
Stress Electrocardiography
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Sensitivity overall: 60-70%
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Single vessel CAD: 50%
2 vessel CAD: 65%
3 vessel CAD: 85%
Specificity 80-85%
For patients without symptoms/ECG
changes, need to achieve 85-90% PMHR
before concluding “negative test for
ischemia.”
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Stress Electrocardiography
in Women
High incidence of false positives
in young, healthy women, no risk
factors and atypical types of chest
pain.
 Decreased sensitivity in women
with documented CHD.
 Consider stress testing with
imaging.
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Stress Testing with Nuclear
Imaging
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Isotope (Thallium201 or Tc99sestamibi)
distributes to myocardium via blood flow
and intact cell membrane Na/K pump.
Resting tissue (imaged before or several
hours after stress) takes up isotope
normally as perfusion is adequate at rest.
Ischemic tissue (stress induced) beyond
coronary stenosis does not take up
isotope intracellulary- appears as
“defect” on scan.
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Stress Testing with Nuclear
Imaging
Resting images compared with
stress images looking for reversible
ischemia.
 Nuclear scans will also show areas of
prior infarction if present: Defect on
both resting and stress images.
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Stress Echocardiography
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Myocardium with normal perfusion
contracts normally, well defined using
ultrasound. Heart normally gets smaller,
with increased EF during
exercise/dobutamine stress.
Ischemic segments (that correlate with
coronary artery that is obstructed) have
decreased or absent contraction. If
multiple or large, heart gets bigger, EF 
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Stress Echo
Images.google.com
Pharmacologic Stress
Testing
Dobutamine + Echocardiography
 Dipyridamole + Nuclear imaging
 Adenosine + Nuclear imaging
 Always combine ECG with imaging
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Nuclear Isotope: Tc99 Sestamibi or
Thallium201
 Echocardiography
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Stress Testing + Imaging
Clearly superior to stress testing
with ECG alone
 Increases sensitivity to 85-90%
 Increases specificity to 90%
 Similar S/S with both exercise and
pharmacologic stress + imaging
 Drawback is cost
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Limitations of ECG for
Ischemia
LVH
 LBBB
 Digoxin
 WPW abnormality
 In patients with above, must use
imaging when considering stress
testing; ECG alone is worthless.
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Echocardiography
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Non-invasive test, combines 2-D with
doppler ultrasound to image the cardiac
chambers, aorta, valves, myocardium,
pericardium and blood flow.
Transthoracic vs TEE
Global and segmental LV function and EF
Hypertrophy, chamber enlargement
Detection of endocarditis TEE
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Echocardiography
Evaluation of Heart Failure
 Valvular stenosis, insufficiency
 Congenital defects, shunting
 Pericardial disease/effusions
 Prosthetic valves
 Ventricular or atrial thrombus
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Radionuclide Ventriculography
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Isotope (Tc99) used to label RBC’s.
Passage of RBC’s over hundreds of cycles
allows reconstruction of the beating
heart.
Excellent for evaluation of EF
Some value in detecting wall motion
abnormalities.
Echocardiography provides more
information and has replaced need
for radionuclide ventriculography in
most settings.
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Radionuclide Angiography
Cardiac Catheterization
Images.google.com
AllRefer Health
Rt Heart Catheterization
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Invasive procedure with risk
Catheter advanced from central vein into
RA, RV, PA and PCW positions. Pressures
obtained. Oximetry performed if
congenital heart disease suspected.
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PCW=LA=LVEDP if MV normal
Measurement of cardiac output and SVR
Invasive monitoring of critically ill
patients.
Complications: Pneumothorax, arterial
puncture, infection, thrombosis.
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Right Heart Pressures
Lt Heart Catheterization
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Catheter advanced from major artery into
aorta, across Ao valve into LV; invasive.
Pressures recorded: Identify AS, MS
Angiography: Contrast (dye) can be
injected into:
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LV to assess contractility and look for mitral
valve regurgitation.
Coronary arteries to identify and define
presence/absence of
stenosis/occlusions.
Complications: Death, stroke, bleeding,
arterial thrombosis/emboli.
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Aortic Pressure
LV Pressure