1 / 12

CHAPTER SIX

CHAPTER SIX. Interpretation of Clinical Test Data Posttest probability of disease is determined by pretest probability and the probability of the test providing a true result Pretest probability determined mainly by angina but also by major risk factors

varen
Download Presentation

CHAPTER SIX

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHAPTER SIX • Interpretation of Clinical Test Data • Posttest probability of disease is determined by pretest probability and the probability of the test providing a true result • Pretest probability determined mainly by angina but also by major risk factors • Exercise testing in the apparently healthy not recommended

  2. INTERPRETING THE DATA • Purpose of the test and patient conditions including medications and resting ECG abnormalities • Objectives of exercise testing address : exercise tolerance, max VO2, hemodynamics (HR, BP), changes associated with electrical functions of heart and limiting signs or symptoms

  3. WHAT DETERMINES MAXIMAL EFFORT? • Failure of HR to increase with increase in exercise • Plateau in oxygen consumption--hard to determine • Lactic acid measure of > 8 mmol • RPE > 17 ( 6-20 scale)

  4. HR and BP RESPONSE • Inability to appropriately increase HR and/or delayed decrease in recovery HR usually indicate heart disease and impact prognosis • Drop or failure to increase SBP with increasing exercise is abnormal • Normal postexercise SBP presents as a progressive decline with a greater drop during passive recovery

  5. ABNORMAL BP RESPONES • SBP greater than 250 mmHg is criteria for test termination • DBP greater than 114 mmHg (115 mmHg in book) is criteria for test termination

  6. MORE • RPP= SBP X HR represent myocardial oxygen consumption--ischemia happens at a reproducible product • Increase of DBP > 10 mmHg questionable as to disease • Some medications make BP responses hard to evaluate

  7. ECG WAVEFORMS • Test 2 – You’ll need to know PQRST and be able to determine HR from an ECG strip

  8. DIAGNOSTIC VALUE OF EXERCISE TESTING • To detect for CAD • Sensitivity • Specificity • Prevalence • Predictive value--positive and negative

  9. SENSITIVITY • Refers to the percent of patients that have disease and test positive for disease= true positive test • A false negative test fails to identify a patient with disease • See box 6-3 for causes leading to false negative tests

  10. SENSITIVITY • Test sensitivity is decreased by failure to reach maximum stress, meds, and poor ECG monitoring • Using the correct precordial leads increase sensitivity

  11. SPECIFICITY • The percent of patients considered normal that present with negative tests=true negative-see box 6-4 for causes for FP • A false positive test incorrectly identifies a person as having disease when they do not • Sensitivity and Specificity of exercise testing vary based on patient selection, test protocols, and ECG criteria for CAD • Sensitivity=68% and Specificity=77%

  12. PREDICTIVE VALUE • Predictive value measures how accurately a test result identifies a person with or without disease • Predictive value is driven by disease prevalence in the population under study

More Related