Transcript CURRENT STATUS OF STRESS TESTING

CURRENT STATUS OF
STRESS TESTING
JOHN HAMATY D.O.
INTRODUCTION
 Form of imprisonment in 1818
 Edward Smith’s observations
TECHNIQUE
 Heart rate
 Blood pressure
 ECG parameters
 Physical appearance
INDICATIONS
 Ischemic heart disease
 Medical efficacy
 Baseline post procedure
 Culprit vessel
 Hypertension management
COMPLICATIONS
 Cardiac arrhythmias
 Sudden death
 Myocardial infarction
 Fatigue
 Heart failure
 hypotension
DIAGNOSTIC VALUE OF
STRESS TESTING
(SENSITIVITY & SPECIFICITY)
 Designed to test how effectively a test
separates subjects with disease from
healthy individuals
 ST segment depression has 84%
specificity for angiographically significant
CAD(assumes 85% heart rate)
Prognostic Value of Testing
 Post MI
 Stable CAD
 Post CABG(3 mos.)
 Post intervention(6 mos.)
 High Risk(Diabetics*******)
 Hypertension
ASSESSING THE APPROPRIATE TEST
FOR THE APPROPRIATE PATIENT
 Treadmill
 Treadmill with imaging
 Pharmacologic
 Echocardiography
PHARMACOLOGIC
Indications
 Patients unable to exercise
 Preoperative risk stratification
 Early postinfarct risk stratification
 Left bundle branch block
 Fixed-rate pacemakers
PHARMACOLOGIC TESTING
Persantine/Adenosine
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

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Needs nuclear

augmentation

Coronary vasodilation 
Bronchospastic

Not for acute

asthmatic’s or severe
COPD
Dobutamine
Inotrope
Vasodilator
Afterload reducer
Increase heart rate
May require atropine
No bronchospastic
component(COPD)
PERSANTINE
 IV dosing of .56ml/kg over 4 minutes
 5 fold increase in coronary blood flow
velocity
 Acts by indirectly increasing intravascular
adenosine levels
 Precursor to adenosine
 Reverse effects with Aminophylline(dosing
from 50-250mg iv injection
ADENOSINE
 Actively transported across cell to activate
the A1 and A2 receptors, stimulates
adenocine cyclase in smooth muscle and
produces vasodilatation
 Leads to increase in cAMP, causes
increase in Ca levels leading to smooth
muscle relaxation
PERSANTINE/ADENOSINECONTRAINDICATIONS
 Bronchospasm- active lung
disease
 AV block
 Taking caffine or
methalxanthines
 Hypotention- <90mm hg
DOBUTAMINE
 Dobutamine is a synthetic
catecholamine, which directly
stimulates both beta-1 and beta-2
receptors. A dose-related
increase in heart rate, blood
pressure, and myocardial
contractility occurs.
DOBUTAMINE
 increases regional myocardial blood flow based
on physiological principles of coronary flow
reserve. A similar dose-related increase in
subepicardial and subendocardial blood flow
occurs within vascular beds supplied by
significantly stenosed arteries, with most of the
increase occurring within the subepicardium
rather than the subendocardium. Thus,
perfusion abnormalities are induced by the
development of regional myocardial ischemia.
DOBUTAMINECONTRAINDICATIONS
 Patients with recent (1 wk) myocardial
infarction; unstable angina; significant
aortic stenosis or obstructive
cardiomyopathy; atrial tachyarrhythmias
with uncontrolled ventricular response;
history of ventricular tachycardia,
uncontrolled hypertension, or thoracic
aortic aneurysm; or left bundle branch
block should not undergo dobutamine
stress testing.
Treadmill Stress Testing
 Must be able to walk!!
 Can be used alone for low risk cases
 Augmentation can be with nuclear or echo
 Physiologic response
 Blood pressure response to exercise
 Exercise prescription
STRESS ECHO
 Can be done with treadmill or dobutamine
 Assesses wall motion
 Evaluates regional and global wall motion
 Fast answers
 No radiation exposure
STRESS ECHO
STRESS NUCLEAR
 Cardiac function
 Relative perfusion
 Real-time imaging
 More objective interpret.
 Additional information
 Quantitation of extent
(LVH, valves)
 Patient convenience
 Cost
of perfusion abnorm.
 More extensive literature
on prognosis