Diagonostic Tests Flashcards
Sensitivity
proportion of those individuals with the disease who have a true positive test
Specificity
proportion of those individuals without the disease with a true negative test
Positive predictive value
proportion of individuals who had a positive test and actually have the disease
Negative predictive value
proportion of individuals who had a negative test and truly do not have the disease
What does troponin assess?
the gold standard for cardiac injury
BNP
protein produced by the ventricles of the heart, important in the diagnosis of heart failure
B-type natriuretic peptide
Normal BUN range
8 to 23 mg/dl
What does elevated BUN indicate?
heart failure or renal failure
Holter Monitoring
Continuous 24-hour electrocardiographic monitoring of a patient’s heart rhythm
Essential to the diagnosis and management of episodes of cardiac arrhythmias and symptoms
Echocardiography
Uses pulse of reflected ultrasound to evaluate the functioning of the heart
Provides real time images of beating heart
Quantify volumes of left ventricle, estimate SV and ejection fraction
Transesophageal Echocardiography
High quality 2D images
Use of flexible endoscope inserted into esophagus
Pharmacological Stress Testing
Used when a patient is unable to perform upright exercise on a treadmill or cycle
Injection of a pharmacological agent to induce physiological stress
Adenosine or dipyridamole-walk protocol
Combined low-level treadmill exercise during adenosine infusion
Ergonovine stimulation
Important diagnostic test of coronary spasm
Performed in cardiac catheterization laboratory
If positive response occurs, patient is managed with medications that reduce or prevent occurrence of spasm
Indications for Cardiac Catheterization
Cardiac arrest or ventricular fibrillation
Pulmonary edema
Intolerance of or noncompliance with medical therapy for angina
Job description mandate
Significant decrease in exercise duration (>35%)
Progressive decline in systolic BP to less than 100 mm Hg during exercise
Evidence of symptomatic hypoperfusion during exercise (intense diaphoresis, pallor, mental confusion with dec in BP)
Left ventricular ejection fraction (<35%)
Ventricular tachycardia with exercise
Endocardial Biopsy
Samples of right or left ventricular endomyocardium may be obtained at time of catheterization
Determines myocardial rejection in patients with a cardiac transplant
May be use to diagnose hypertrophic and congenital cardiomyopathy
ABI greater than 1.10
normal
ABI 0.5 to 1
claudication
pain in calf with ambulation
ABI 0.2 to 0.5
critical limb ischemia
atrophic changes
rest pain
wounds
ABI less than .02
severe ischemia
gangrene/necrosis
Submaximal Tests
Terminated on achievement of predetermined end point (unless symptoms otherwise limit completion of the test
Low-Level Exercise Testing
Performed when patients are post-MI or CABG
Useful in predicting subsequent course of MI or bypass surgery
Identifying high-risk patients
Contraindications for low level testing
unstable angina or angina pectoris at rest severe heart failure serious arryhthmias at rest second or third degree heart block disabling MSK abnormalities valvular heart disease BP> 180/105 no patient consent
Criteria for Termination of Maximal Testing
Increasing frequency or pairing of premature ventricular complexes
Development of ventricular tachycardia
Rapid atrial arrhythmias, including atrial fibrillation or atrial flutter, with uncontrolled ventricular response rates
Development of second- or third-degree heart block
Increased angina pain (Level 2 on a scale of 4)
Hypotensive blood pressure response (20 mm Hg or greater decrease)
Extreme shortness of breath
Dizziness, mental confusion, or lack of coordination
Severe ST-segment depression.
Observation of the patient reveals pale and clammy skin (pallor and diaphoresis)
Extremely elevated systolic or diastolic blood pressure, or both, which may or may not be associated with symptoms
On achievement of predicted maximal heart rate; it is usually safe to proceed with the test beyond the predicted maximal heart rate if the patient is able and willing to continue and if other indications to terminate the test are absent.
Presence of leg fatigue or leg cramps or claudication pain
Patient request for termination of test
