SPDX Week 3 Stress Testing PDF

WEEK 3 BRIEF HISTORY Angina was first STRESS TEST described in 1772 by the English physician...

WEEK 3 BRIEF HISTORY Angina was first STRESS TEST described in 1772 by the English physician William Heberden. The ST segment is the flat, isoelectric section of the Historical Note ECG between the end of the S wave (the J point) and the beginning of the T wave. The ST Segment represents the interval between ventricular The “cornerstone” of depolarization and repolarization. modern stress testing was the recognition of the importance of ST segment changes to predict the presence of coronary artery disease (CAD)  ST depression occurs when the J point is displaced below baseline. Historical Highlights There are multiple conditions associated with ST depression. 1918 ST depression first noted during angina (Bousfield) 1928 ST changes during exercise (sit ups) are associated with chest pain & decreased cardiac blood flow (Feil & Siegel) 1929 Master’s Step test, first “standard” exercise protocol (Master) 1932 ST depression is present in only 75% of patients with angina during exercise (similar to percentages today). (Goldhammer & Scherf) 1938 First to use maximal exercise testing to test for CAD (Missal) Historical Highlights Historical Highlights 1952- Treadmill testing used with set criteria to screen for 1940- Continuous EKG monitoring, depression > 1.0 mm is CAD (Yu et al.) ST depression > 1.0 mm clinically significant (Riseman et al.) Change in T wave (upright - inverted) 1941- EKG changes after exercise can be useful to detect Increase T wave amplitude & Q-T duration CAD (Master & Jaffe) 1942- The Harvard Step Test used to assess fitness from 1954- Cycle tests used to predict fitness (Astrand) HR during recovery (Johnson et al.) 1956- Bruce established the guidelines used today: treadmill, 1950- Maximal exercise (stair climbing) was more sensitive with EKG, during exercise (88%) to detect CAD than submaximal exercise (39%) 1969- Refined interpretation of ST changes (V5 or CM5 most (Master’s test) (Wood et al) sensitive leads) (Blackburn et al.)  Dr. Robert A. Bruce, Bayes Theorem (1970s and 1980s) the father of the treadmill exercise Named after 18th-century British mathematician Thomas stress test, died on February 12, 2004 Bayes, is a mathematical formula for determining conditional when he was 87 years of age. probability. Dr. Bruce used improvements in both Conditional probability is the likelihood of an outcome EKG's and treadmills to perfect his new procedure. occurring, based on a previous outcome having occurred in His first studies, published in 1949, similar circumstances. analyzed minute-to-minute changes in respiratory and circulatory function of The probability of a “true” positive stress test depends normal adults who took a single-stage on the pre-test risk of the patient treadmill test. He then published a paper describing a multistage test in 1963. WHAT IS STRESS TESTING? WHAT IS STRESS TESTING? Test used in Medicine to measure heart’s ability to respond to external stress in a controlled clinical environment Stress test makes it easier to identify and A stress test is a very commonly performed test evaluate certain heart issues, such as: to learn: 1. Issues with your muscle or valves. a) How well your heart pumps blood. 2. Adequate blood supply to your heart muscle. b) Whether your heart is receiving an adequate 3. Electric stability of your heart at rest and during blood supply. exercise. c) How you perform on physical activity (riding a treadmill or stationary bike) compared with other people your age and sex. d) If your symptoms (chest discomfort, shortness of breath, feeling like your heart is racing or even dizziness) can be reproduced while performing physical activity.  Types of Stress Testing How does a stress test work? A heart stress test starts by making your heart pump harder and faster. Healthcare providers assess your response to the increased workload by measuring: 1. Blood pressure. 2. Heart rate. 3. Oxygen levels. 4. Electrical activity in your heart. 5. How hard your heart is working compared with others your age and sex. Exercise Stress Test Pharmacological Stress Test This is the most A pharmacological stress test is common and basic done when an exercise stress heart stress test. test is not possible due to Shows how your heart physical limitations like back works during physical trouble, joint disease, prior activity. stroke, dizziness or shortness of It usually involves breath. walking on a treadmill A chemical or pharmacological or riding a stationary stress test uses a medication bike that increases your heart load in the place of exercise.  Pharmacological Stress Test Nuclear Stress Test A nuclear stress test, also called a myocardial perfusion scan, is a type of nuclear medicine procedure. INDICATIONS OF PHARMACOLOGICAL STRESS A radiotracer (Tc-99 sestamibi or TESTING thallium) is injected. Scans are acquired with a Patients inability to exercise adequately. gamma camera to capture The chosen test cannot be performed images of the blood flow. readily with exercise. Usually done on two separate days. Why might we need a stress test? Indications of Exercise Testing You may need this test to detect heart problems like: Diagnose coronary artery disease. Congenital heart disease. Diagnose heart rhythm problems (arrhythmias). Congestive heart failure. Guide treatment of heart disorders. Coronary artery disease. Heart valve disease. Hypertrophic cardiomyopathy. People with high-risk occupations (like pilots or professional athletes) may also need stress tests.  Risks Contraindications Acute M.I High risk of unstable angina Low blood pressure Uncontrolled cardiac arrthymias Abnormal heart rhythms (arrhythmias). Symptomatic severe aortic stenosis ́ Pulmonary Heart attack (myocardial infarction). infarction Acute myocarditis Acute aortic dissection TMT ROOM Safety Precautions and Equipment The treadmill should have Front and side rails for subjects to steady themselves. An emergency stop button should be readily available to the staff only.  TREADMILL Pre –Test Preparation Preparation for Exercise Testing Any history of light headedness, fainting while The subject should be instructed not to eat or smoke at exercising should be asked. least 2 hours prior to the test. The physician should also ask about family history Unusual physical exertion should be avoided before and general medical history, making note of any testing. considerations that may increase the risk of sudden Specific questioning should determine which drugs are death. being taken. A brief physical examination should always be Because of a greater potential for cardiac events with the performed prior to testing to rule out significant sudden cessation of -blockers , they should not be outflow obstruction. automatically stopped prior to testing.  Treadmill Test Exercise Protocols It usually involves walking on a treadmill at increasing In general, 6 to 12 minutes of continuous progressive levels of difficulty, while electrocardiogram, heart rate, exercise during which the myocardial oxygen demand is and blood pressure are monitored. elevated to the patient's maximal level is optimal for diagnostic and prognostic purposes. The protocol should include a suitable recovery or cool- down period. Various Protocols BRUCE PROTOCOL Treadmill protocols Bruce The Bruce multistage maximal treadmill protocol has 3-minute Cornell periods to allow achievement of a steady state before work-load is increased for next stage. Balke ware Acip The Bruce protocol treadmill test was designed by cardiologist mAcip Robert A. Bruce in 1963 as a non-invasive test to assess patients with suspected heart disease. Naughton Weber In this capacity, is perhaps more widely known as a stress test or exercise tolerance test. Bicycle ergometer  Termination of Exercise Testing Termination of Exercise Testing Moderate to severe chest pain Positive test Severe shortness of breath b. A flat or down sloping depression of the ST segment > Abnormally high or low blood pressure 0.1 mV below baseline An abnormal heart rhythm Dizziness Negative test Fatigue a. Target heart rate is not achieved. Certain changes in your electrocardiogram Responsibilities of a Cardiology Limitations of Treadmill Stress Test Technologist during Exercise Stress Tests Sensitivity- 68% Ensure the patient has signed all relevant forms, followed preparation guidelines, and that their medical history was provided. Specificity- 77 % Ensure the patient exercises for as long as possible in order to get a complete and accurate reading. Make sure the patient knows that they should speak up if they experience any chest or arm pains, dizziness or other unusual symptoms. Monitor the ECG continuously and be prepared to stop the test immediately if any anything warning signs appear. Thank You End of Pages