Cardiac stress tests are used to diagnose coronary artery disease by assessing how the heart responds to induced stress. Stress can be induced through exercise on a treadmill or stationary bike or through pharmacological agents. The test measures for changes in electrocardiography, echocardiography, or nuclear imaging before and after stress is applied to detect any signs of ischemia. Stress tests are indicated for diagnosing chest pain, prior heart attacks, or post-revascularization and help evaluate the heart's response to physical or drug stimulation.

1. Cardiac stress tests
Porya Hassan Abadi

2. Introduction
• Diagnostic test for coronary artery disease
• Main aim is to assess the coronary flow system
• Measures ability of heart to respond to stress
• Stress is induced by drugs or exercise under
clinical supervision

3. Clinical case
• 50 y/o female with diabetes, HTN, smoker
• Nonspecific substernal chest pain
• Slight dyspnoea
• ECG nonspecific
• Normal cardiac markers

4. Indications
• Diagnosis of coronary disease in patients with:
– Stable chest pain
– Unstable chest pain stabilised with therapy
– Previous MI
– Post revascularisation (CABG)

5. Contra-indications
• Acute myocardial infarction (within 2 d)
• Unstable angina not previously stabilized by
medical therapy
• Uncontrolled cardiac arrhythmias causing
symptoms or hemodynamic compromise
• Symptomatic severe aortic stenosis
• Uncontrolled symptomatic heart failure
• Acute pulmonary embolus or pulmonary
infarction
• Acute myocarditis or pericarditis
• Acute aortic dissection

6. TYPES OF STRESS TESTING
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• EXERCISE
a. Treadmill
b. Bicycle
• PHARMACOLOGICAL
a. Adenosine
b. Dipyridamole
c. Dobutamine
d. Isoproterenol

7. Physical stimulation
• Test is done by exercise on treadmill or pedaling
an stationary bicycle.
• Constantly monitored (ECG,BP and heart rate)

8. 8
TEST OF CHOICE IN THOSE
WITH:
• NORMAL BASLINE ECG
• ABLE TO EXERCISE
• NO PRIOR REVASCULARISATION

9. How long? How fast?
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• Maximal Test: The patient achieves 85% of
MPHR (maximal predicted HR = 220 - Age)
• Submaximal Test: The patient becomes
symptomaticchest pain, dyspnea (MPHR
generally not achieved)

10. When the termination is
needed?
• Drop in systolic blood pressure (SBP) despite an
increase in workload
• Moderate-to-severe angina
• Increasing neurological symptoms (eg, ataxia,
dizziness, near-syncope)
• Signs of poor perfusion (cyanosis or pallor)
• Subject’s desire to stop
• Sustained ventricular tachycardia
• ST elevation (> 1 mm) in leads (other than V 1
or aVR)

11. Safety and risk of exercise test
• Nonselected patient population: Mortality <
0.01%
• Within 4 weeks of MI: Mortality = 0.03% and
Morbidity = 0.09% (reinfarction, cardiac arrest)

12. Pharmacological Stress Test
• Stress is induced using agents such as :
1. Vasodilators such as: Adenosine and
Dipyridamole not used asthma or COPD
2. B2 agonist such as: Dobutamine

13. INDICATIONS OF
PHARMACOLOGICAL STRESS
TESTING
13
• Patients inability to exercise adequately because
of physical or psychological limitations.
• The chosen test cannot be performed readily
with exercise (e.g. PET scanning).

14. METHODS OF DETECTING
ISCHEMIA DURING STRESS
TESTING
14
• Electrocardiography
• Echocardiography
• Myocardial perfusion imaging
• Positron emission tomography
• Magnetic resonance imaging

15. ECG changes

16. Stress echocardiography
• echocardiography is performed both before and
after the exercise used to detect:
1. Wall motion abnormalities
2. Ejection fraction
3. Valvular heart disease

17. Nuclear stress test
(Myocardial perfusion imaging)
• a radiotracer (Tc-99 sestamibi or thallium) is
injected
• scans are acquired with a gamma camera to
capture images of the blood flow.
• Usually done on two separate days:
1. After rest
2. After injection of stress stimulating drugs