Cardiovascular Diagnostic Tests and Procedures Flashcards
Purposes of medical tests
- Facilitate the achievement of a correct diagnosis
- Aid in the prevention of complications
- Develop information to determine a prognosis
- Identify subclinical disease states
Define Sensitivity
- Proportion of individuals with the disease who have a true positive test
Define Specificity
- Proportion of individuals w/o the disease with a true negative test
Describe positive versus negative predictive values
- Positive: proportion of individuals who had a positive test & actually have the disease
- Negative: proportion of individuals who had a negative test & truly do not have the disease
Serum enzymes and cardiac biomarkers may aid in assessing the _________________ or the _________________
- Degree of myocardial damage
- Effectiveness of reperfusion
Serum Enzymes and Cardiac Biomarkers that are most commonly used for the diagnosis of cardiac injury
- Creatine kinase (CK-MB isoenzyme): abnormal if >5%
- Troponins: gold standard for assessing myocardial damage
Describe acute coronary syndrome (ACS)
- Unstable anginia: absences of cardiac myocyte death
- MI: STEMI resulted from total occlusion thrombus and NSTEMI resulted from partial occlusion with/without collateral circulation
Define myoglobin
- Heme protein found in all muscle tissue; potential diagnostic tool for acute MI
Define B type natriuretic peptide (BNP)
- Protein produced by the ventricles of the heart used in diagnosing heart failure, with implications for CAD
Enzyme and isoenzyme levels increase within the first _______ hours after myocardial injury and reach their individual peaks at different rates
- 2 to 6 hours
BNP lab values
- Normal: <100
- Pro BNP normal: <300
- Heart failure likely if >400
What is considered a major risk factor for CAD in the blood
- Hyperlipidemia (elevation in blood lipid levels)
Serum cholesterol and triglycerides are blood lipids of concern when elevated
- Elevated cholesterol is associated with ingestion of excess amounts of saturated fat and cholesterol
- Elevated triglyceride levels are defined as being higher than 150 mg/dL
Highly sensitive C-reactive protein (hs-CRP) assay is available to determine heart disease risk
- Normal/low risk: <1.0
- Average: 1.0-3.0
- High risk: >3.0
What 3 components are included in a complete blood cell count test
- White blood cells (WBC)
- Hemoglobin (Hb)
- Hematocrit
Hemoglobin (Hb) below what value is a red flag for out of bed activity
- <8
Hematocrit is a significant indicator of the viscosity of the blood; list the implications for elevated/low lab values
- Critically low Hb and hematocrit (<15-20%) may lead to cardiac failure or death
- Hb values >20 or hematocrit >60% will increase viscosity of the blood causing increased resistance & stress on the heart
Prothrombin time and partial thromboplastin time measure ___________
- Coagulation of blood
Electrolytes involved in maintaining cell membrane potential that are most important to monitor
- Sodium (Na)
- Potassium (K)
- Magnesium (Mg)
Patients receiving diuretics (e.g., for hypertension or heart failure) should have their ________ and ________ levels monitored carefully because some diuretics act on the kidney
- Sodium and potassium
Critical values and implications for sodium levels
- Critical: <120 or >160
- Hypernatremia:thrist, confusion, irritability, hyperreflexia, seizure, coma, tachycardia, hypotension, oliguria
- Hyponatremia: HA, lethargy, hyporeflexia, seizure, coma, OH, pitting edema, confusion, weakness, nausea
Critical values and implications for potassium levels
- Critical: Newborn -> <2.5 or >8; Adult -> <2.5 or >6.5
- Hyperkalemia: muscle weakness or paralysis, muscle tenderness, paresthesia, dysrhythmia, bradycardia
- Hypokalemia: extremity weakness, hyporeflexia, paresthesia, leg cramps, dysrhythmia, hypotension
Critical values and implications for magnesium levels
- Critical: <0.5 or >3
- Hypermagnesemia: N/V, hyporefelxia, hypotonia, somnolence (drowsy), bradycardia, dysrhythmia, hypotension, respiratory depression
- Hypomagnesemia: hypertonia, hyperreflexia, tremors, muscle cramping, seizures, apathy, nystagmus, dysrhythmias
Elevated BUN may indicate
- renal failure, uremia, or retention of urea in the blood
- Unsuitable as a single measure for renal disease; creatine value should also be noted
Critical values and implications for serum creatine levels
- Critical: >4 indicates serious impairment in renal function
- Elevated: edema, dyspnea, abdominal/back pain, arthralgia, myalgia, myopathy, fatigue/malaise, insomnia, HA, confusion, pruiritis
- Low: fatigue (uncommon)
Normal glucose levels
- Fasting normal: 90-130
- Elevated 120-130 suggests prediabetic states & warrants further testing for DM
- Hyperglycemia: >200 denotes a crisis situation requiring immediate insulin (should not exercise)
- Normal A1C: <5.7%
Symptoms of hyper/hypo glycemia
- Hyper/Ketoacidosis: N/V, fruity breath, confusion, weak/rapid pulse, kussmaul respiration
- Hypoglycemia: perspiration, weakness, pallor, nervousness, seizure, lethargy, irritability, tachycardia, palpitation, altered mental status, hunger, HA, shaking, blurred vision, LOC
Describe Holter monitoring
- Continuous 24hr ECG monitoring of heart rhythm
- PT should obtain interpretation of results to determine whether modifications are needed in the pt’s activities
- Pts with abnormal Holter monitor results may be referred for treadmill exercise testing to assess arrhythmia or for echocardiography to assess valve functioning
Patients demonstrating _________________ with ambulatory monitoring may be referred to electrophysiologic mapping studies (EPS)
- Life threatening arrhythmias
Describe an echocardiography
- Provides real time images of beating heart
- Uses pulses or reflected ultrasound to evaluate functioning of the heart
- Transducer is placed on chest wall at the 3rd-5th intercostal space near L sternal border
Information that can be obtained from the echocardiogram
- Size of ventricular cavity
- Thickness/integrity of inter arterial/ventricular septa
- Function of valves
- Motions of ventricular wall
- Degree of normal thickening of the myocardium
Advantages and disadvantages of a PET (position emission tomography)
- Direct measurement of metabolic function & blood flow of the heart
- Advantages: gold standard for blood flow, detects jeopardized but viable myocardium w/o exercise
- Disadvantages: requires specialized tech & highly trained staff, costly & not available at many hospitals
What can different types of CT scans show in the heart
- Used to identify masses in cardiovascular system or to detect aortic aneurysms or pericardial thickening
- Single-photon emission computed tomography (SPECT)—detects and quantifies myocardial perfusion defects and contractility defects
- Electron beam computed tomography—detects calcium in coronary arteries and quantifies coronary atherosclerosis
Describe a Multigated acquisition imaging (MUGA)
- Calculates L ventricular ejection fraction (LVEF)
- Radioactive tracer injected intravenous & gamma camera acquires images
Describe MRI of the heart
- Evaluates morphology, cardiac blood flow, and myocardial contractility
- Similar diagnostic accuracy as PET imaging, but more available and less expensive
Describe MRA (magnetic resonance angiogram)
- uses magnetic and radio wave energy to take pictures of blood vessels