Exercise Test: Practice and Interpretation Jidong Sung Division of Cardiology Samsung Medical Center Sungkyunkwan University School of Medicine
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Aerobic capacity and survival Circulation 117:614, 2008
Exercise stress test Detection of myocardial ischemia Diagnosis of coronary artery disease Evaluation of exercise capacity Prediction of prognosis Detection of exercise-induced arrhythmia Differential diagnosis of cardiac symptoms, such as dyspnea Screening in asymptomatic population?
Mode of stress Exercise the most physiologic mode treadmill, bicycle limitation: patients with severe obesity, gait disturbance, joint problem, etc. Pharmacological stress adenosine: coronary steal dobutamine: increase in cardiac contractility and heart rate 6-minute walk test
Treadmill vs. bicycle Mode of stress Patients with orthopedic problem BP measurement Obtaining quality ECG recording Need for patient's motivation Cost of equipment Size of equipment Noise during test Treadmill physiologic (walking) difficult to apply may be difficult may be difficult moderate higher bigger higher Bicycle ergometer may be unfamiliar relatively easier relatively easier relatively easier high lower smaller lower
Exercise protocols
Pharmacological stress Useful in patients who cannot exercise Not as physiologic as exercise stress OK for detection of myocardial ischemia Limited information for functional capacity Adenosine single IV bolus antidote: theophylline Dobutamine continuous infusion with dose escalation antidote: beta blocker Palpitation and/or anginal symptom may appear.
Detection of myocardial ischemia ECG less expensive test accuracy lower than imaging not feasible in LBBB, LVH with ST change, WPW syndrome false positive Echo may be difficult in patients with poor echo window test results immediately available myocardial SPECT Thallium radiation potential for false negative multi-vessel disease MRI expensive no poor image
Accuracy for diagnosis of CAD Exercise ECG: Sensitivity and specificity around 70 s% + imaging technique: About 10% improvement both in sensitivity and specificity
Predictive value of exercise tests Depends on pretest probability of CAD Diagnostic power of the exercise test is maximal when the pretest probability of CAD in intermediate (30-70%)
Preparation Strict NPO usually not needed Not to eat, drink alcohol or caffeine or smoke for 3 hours Should permission be obtained? Medications with anti-anginal effects (beta blockers, calcium channel blockers, nitrates, etc) should be withdrawn temporarily, if initial diagnosis of CAD is the objective. Tests should be attended by a physician or medical personnel should be immediately available.
ACC/AHA Guidelines: Absolute and Relative Contraindications to Exercise Testing Absolute Recent significant change in the rest electrocardiogram (ECG) suggestive of significant ischemia or other acute cardiac event Acute systemic infection accompanied by fever, body aches, or lymphadenopathy Acute myocardial infarction (within 2 days) High-risk unstable angina 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 Relative* Left main coronary stenosis Moderate stenotic valvular heart disease Electrolyte abnormalities Severe arterial hypertension (suggested definition: systolic blood pressure > 200 mm Hg and/or diastolic blood pressure > 110 mm Hg) Tachyarrhythmias or bradyarrhythmias Hypertrophic cardiomyopathy and other forms of outflow tract obstruction Mental or physical impairment leading to inability to exercise adequately High-degree atrioventricular block Neuromuscular, musculoskeletal, or rheumatoid disorders known to be exacerbated by exercise Ventricular aneurysm Uncontrolled endocrine disorder (e.g., diabetes, thyroid) Chronic infectious diseases (mononucleosis, hepatitis, AIDS)
ACC/AHA Guidelines: Indications for Terminating Exercise Testing Absolute Drop in systolic blood pressure >10 mm Hg from baseline blood pressure despite an increase in workload, when accompanied by other evidence of ischemia Moderate to severe angina (defined as three of four on exercise angina scale) Increasing nervous system symptoms (e.g., ataxia, dizziness, near-syncope) Signs of poor perfusion (cyanosis or pallor) Technical difficulties in monitoring electrocardiogram (ECG) or systolic blood pressure Subject's desire to stop Sustained ventricular tachycardia ST elevation ( 1.0 mm) in leads without diagnostic Q waves (other than V1 or avr) Relative Drop in systolic blood pressure >10 mm Hg from baseline blood pressure despite an increase in workload, in the absence of other evidence of ischemia ST or QRS changes, such as excessive ST-segment depression (>2 mm of horizontal or downsloping ST segment depression) or marked axis shift Arrhythmias other than sustained ventricular tachycardia, including multifocal PVCs, triplets of PVCs, supraventricular tachycardia, heart block, or bradyarrhythmias Fatigue, shortness of breath, wheezing, leg cramps, or claudication Development of bundle-branch block or IVCD that cannot be distinguished from ventricular tachycardia Increasing chest pain Hypertensive response (suggested definition: systolic blood pressure > 250 mm Hg and/or a diastolic blood pressure > 115 mm Hg)
Interpretation of ST segments 1: PQ junction 2: J points 3: ST80
Duke treadmill score (DTS) DTS=exercise time-(5xst deviation)- (4xexercise angina) 0=none 1=nonlimiting 2=exercise-limiting. The score typically ranges from -25 to +15. low-risk +5 moderate-risk -10 to +4 high-risk -11
Exercise Parameters Associated with Adverse Prognosis and Multivessel Coronary Artery Disease Duration of symptom-limiting exercise < 5 METs Failure to increase systolic blood pressure 120 mm Hg, or a sustained decrease 10 mm Hg, or below rest levels, during progressive exercise ST-segment depression 2 mm, downsloping ST segment, starting at <5 METs, involving 5 leads, persisting 5 min into recovery Exercise-induced ST-segment elevation (avr excluded) Angina pectoris at low exercise workloads Reproducible sustained (>30 sec) or symptomatic ventricular tachycardia
M/54, atypical chest pain
M/53 무증상, 건강검진하러오심 Smoking 1 pack/d
Stage 3
Stage 4
Recovery
Coronary CT angiogram
Summary Exercise stress test is useful in Diagnosis of coronary disease Prediction of cardiovascular prognosis Evaluation of aerobic exercise capacity planning and prescription for exercise training