Stress Test1

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� Stress test involves stressing the heart + evaluating cardiac response to stress.

� Indications : Diagnose CAD ( patients with risk factors and symptoms of

chestpain. Assess pre-test probability)

In a person with known CAD, for assessing the functional capacity i.e; safety of work/ recreation ( Sub-maximal stress test)

� Contraindications : STEMI less than 4 days Acute aortic dissection Myocarditis, Pericarditis Third degree heartblock Poorly controlled Heart failure Severe AS with valve area < 1cm2

� For patients presenting with chestpain and CAD riskfactors, rule out Acute MI first with serial cardiac

enzymes before sending for Stress test



Stress Test

Components

Types of Stress

- Tachycardic

-Vasodilator

- Inotropic

Evaluating Response to Stress- Clinical features

- EKG changes

- Nuclear component/ Myocardial perfusion study

- Echocardiogram ( wall motion

abnormalities)



� Exercise Stress Test

Tachycardic type of stress ² Increase the heart rate bymaking the patient walk on a treadmill ( Target HeartRate = 220-age) and evaluate response to stress.

Evlauating Cardiac response� Clinical features ² observe for chestpain, sob during stress

� EKG changes ( observe for ST depressions > 2mm during stress, ventricular arrhythmias)x Specificity of this assessment is lowered ( more false positives) if there are

resting ST-T changes already eg: LVH, LBBB, WPW, Digoxin use)

� Adding Myocardial perfusion study ( Nuclear component)- Thallium or Sestamibi ( Technitium)

x Evaluate for the tracer uptake ² A fixed defect suggests infarcted t orhybernating myocardium. Reversible defect ( tracer uptake on stress andresolves with rest) suggests ischemia

� Echocardiogram ( Exercise Stress Echo) ² observe wall motion abnormalities, assesses viability ( viable ifmyocardial wall is akinetic at rest and improved withstress)



Exercise Stress Test (treadmill)� most preferred test in anyone who can exercise well as it

allows to assess exercise capacity and symptoms also apartfrom evaluating ST segment response.

� most sensitive if patients can reach 85% of Target Heart Rate(220-age)

� EKG component alone is sufficient if there is a Lowprobability of CAD. EKG component specificity is lower forpatients with resting EKG changes ( LBBB, earlyrepolarizations, LVH, WPW, pacemaker rhythms)

� Combining nuclear component increases sensitivity andspecificity. Nuclear imaging is preferred when patient hasintermediate probability of CAD.

� In LBBB, LVH, WPW , Paced LV rhythms, using a tachycardicstress may produce reversible defects on myocardialperfusion study in the septal area even in absence of CAD (False Positives) so, the solution here is to use vasodilatorstress ( Stress them with out increasing the heart rate

).



Positive Inotropic Stress: Dobutamine Stress Echo� Mechanism :

Dobutamine increases Heart rate as well as contractility of myocardium andproduces ischemia.

Echo is then used to evaluate wall motion abnormailities during dobutamineinfusion. An ischemic myocardial wall is hypokinetic . Also, useful to evaluateVIABILITY ( when in doubt regarding myocardial stunning vs. Scar) A scar is

Akinetic and does not improve with stress. A stunned myocardium (viable) maybe initially akinetic but improves with stress.

� Preferred Choice in

� Patients who can not walk and who also have contra indications for DipyridamoleStress ( Moderate to severe COPD or asthma, High grade heartblocks)

� Post Ischemia patients or Ischemic Mitral regurgitation ( To assess viability)

�

Not good for� patients with LBBB, on beta blockers, paced rhythm, freq PVCs or atrial

arrhythmias, or poorly controlled hypertension

� Prior to Dobutamine stress test, hold AM dose of b-blocker



� A 52 y/o man with presents to your office with complaints ofexertional chest pain for the past 4 weeks. The chest pain isusually left sided, occurs on walking about three blocks and goesaway with rest. He has developed a habit of taking rest when thechest pain comes and he did not think it needed medical attention until his friend told him yesterday that it might be a symptom ofheart disease. He is concerned and requests your

recommendation. He denies any chest pain or shortness of breathnow. He also reports no change in quality or intensity of his chestpain. His past medical history is significant for Hypertension andSmoking . His medications include lisinopril andhydrochlorthiazide. Physical examination is benign. The next beststep in establishing the diagnosis in this patient is :

� Electrocardiogram� 2 D -Echocadiogram� Exercise ² EKG Stress Test� Dobutamine Stress Echocardiogram� Persantin Stress Test� Cardiac Catheterization



� Exercise EKG Stress test is the preferred test in evaluating patients who can walk and are presenting with symptomstypical of CAD. The patient gives a history of typical exertional chest pain that improves with rest. This highlysuggestive of stable angina.

� The patient has no chest pain now. A resting ECG is useful to show if there are any baseline changes but it will notestablish the diagnosis. An ECG should be obtained during stress to establish the diagnosis of ischemic heart disease

� In patients who can walk, Exercise stress is the preferredmodality since one can also assess the symptoms, ekgchanges and functional capacity. In patients who cannotwalk, persantin (dipyridamole) stress is preferred

� Dobutamine echocardiogram is reserved for patients who can not walk and have contraindications to dypridamolestress test.



� A 65 y/o man with presents to your office with complaints of exertionalchest pain for the past 4 weeks. The chest pain is usually left sided, occurson walking about three blocks and goes away with rest. He has developeda habit of taking rest when the chest pain comes and he did not think itneeded medical attention until his friend told him yesterday that it mightbe a symptom of heart disease. He is concerned and requests yourrecommendation. He denies any chest pain now. He also reports no changein quality or intensity of his chest pain. His past medical history is

significant for pacemaker insertion for a symptomatic second degree heartblock, Hypertension, and Smoking . His medications include lisinopril, atenolol and hydrochlorthiazide. Physical examination is benign. An EKGis obtained which reveals pacemaker rhythm with secondary ST-T changes.The next best step in establishing the diagnosis in this patient is :

� 2 D -Echocadiogram

� Exercise Stress Test ( Treadmill Stress Test)� Dobutamine Stress Echocardiogram� Persantin Stress Test� Cardiac Catheterization



� Persantin is the preferred option for stress when ExerciseStress Test is not useful or can not be done.

� Patients with pacemaker rhythms, LBBB and severe LVH, will have baseline EKG changes that may make EKGcomponent of the Stress test difficult. However, in theseconditions, Tachycardic stress ( Exercise Stress test) mayalso produce false positive defects on nuclear imaging. So, the solution is to use a different type of stress such asvasodilator stress ( Persantin). Moreover, this patient wasalso on beta blocker which makes it difficult to achievetarget heart rate during the Exercise Stress.

� Dobutamine stress test is reserved for patients withbronchospasm or heartblocks ( in conditions wherepersantin is contraindicated)

� If stress test revealed ischemia, cardiac catheterization should be performed.



�

A 65 y/o man with presents to your office with complaints ofexertional chest pain for the past 4 weeks. The chest pain isusually left sided, occurs on walking about one block and goesaway with rest. He denies any chest pain now. He also reports no change in quality or intensity of his chest pain He also reportshaving been diagnosed with peripheral arterial disease about 2months ago for which he was advised exercise therapy. He does

experience leg pain on walking about one block which also improves with rest. His past medical history is significant formoderate COPD, Hypertension and a hernia repair about 3 yearsago. His medications include lisinopril, hydrochlorthiazide andtiotropium inhaler. Physical examination is benign. The next beststep in establishing the diagnosis in this patient is :

� 2 D -Echocadiogram� Exercise Stress Test ( Treadmill Stress Test)� Dobutamine Stress Echocardiogram� Persantin Stress Test� Cardiac Catheterization



� This patient presents with symptoms suggestive ofischemic heart disease. So, needs a stress test to establish diagnosis.

� He cannot walk to his maximum secondary to peripheral arterial disease and this will limit theexercise. So, exercise stress test can not be done.

� He has moderate COPD. Using persantin in

patients with COPD/ asthma can exacerbatebronchospasm .

� The preferred choice in this patient is, therefore, Dobutamine Stress Echo.

Stress Test1

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