current status of stress testing john hamaty d.o

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

PHARMACOLOGICIndications

Patients unable to exercise Preoperative risk stratification Early postinfarct risk stratification Left bundle branch block Fixed-rate pacemakers

PHARMACOLOGIC TESTING

Persantine/Adenosine

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/ADENOSINE-CONTRAINDICATIONS

Bronchospasm- active lung disease

AV blockTaking caffine or

methalxanthinesHypotention- <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.

DOBUTAMINE-CONTRAINDICATIONS

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

Real-time imaging

Additional information

(LVH, valves)

Patient convenience Cost

Relative perfusion

More objective interpret.

Quantitation of extent

of perfusion abnorm.

More extensive literature on prognosis