L1: Diagnostics in Cardiology Flashcards
What are the 2 types of electrocardiography tests?
12-Lead EKG
Telemetry
What does an EKG detect?
-The electrical activity occurring in the heart (series of upward + and downward - deflections)
When is the use of an EKG indicated?
- Most helpful in acute setting, especially ACUTE CHEST PAIN (Angina and MI)
- Palpitations
- Screening for left ventricular hypertrophy
- Can evaluate for past myocardial infarction
What are the contraindications for EKG?
None
but can be subjective so best to have a baseline for comparison
How does Telemetry work?
Continuous EKG monitoring in an inpatient setting
What are the indications for telemetry?
Hospital admission for chest pain or possible acute coronary syndrome
Name the cardiac enzymes.
- Troponin
- CK, CK-MB
How are we able to detect cardiac enzymes?
Cardiac injury results in disruption of myocyte membrane, therefore cardiac enzymes are measurable biomarkers of cardiac injury
What does troponin do in the heart?
- Regulates muscle contraction
- Cardiac regulatory protein complex that controls the calcium-mediated interaction of actin and myosin
What are the 2 types of cardiac troponin enzymes?
cTn I and cTn II
What are the indications for Troponin measurement?
- Preferred method of dx and prognosis in ACUTE MI
- Biomarker of cardiac injury
Which cardiac enzyme is most sensitive and more specific?
Troponin»_space;» CK-MB
*If available, high-sensitivity cardiac troponin is preferred
In what situations would troponin levels increase?
Cardiac injury:
- Trauma
- Surgery
- Inflammation
- Infection
What is important to remember when measuring troponin levels in regards to detecting acute ischemia?
Always obtain serial enzymes to monitor the rise and fall (remember some pts may have consistently elevated levels)
What does Creatine Kinase do in the body? Where is it found?
- Facilitates movement of high-energy phosphates into and out of the mitochondria
- Found in a number of tissues (heart, brain, SM)
Is CK or CK-MB more specific to the heart?
CK-MB
What is the onset, peak, and duration of CK (total and MB) levels following cardiac injury?
Onset: 3-12 hours
Peak: 18-24 hours
Duration: 36-48 hours
What is the onset, peak, and duration of Troponin levels following cardiac injury?
Onset: 3-12 hours
Peak: 18-24 hours
Duration*: Up to 14 days (in system longer which is better for testing compared to CK-MB)
What are the 2 kinds of echocardiography?
- Transthoracic echocardiogram (TTE)
- Transesophageal Echocardiogram (TEE)
How does ultrasound work (electrocardiography)?
- High frequency sound pulses travel into tissues and sound waves are reflected back to crystal probe (provides 2D image)
- Gives apical (upside down) view of 4 chamber heart
What is the primary indication for a TTE? What are some other indications?
-Primary noninvasive modality for quantitative/qualitative EVAL OF CARDIAC ANATOMY AND FUNCTION
Can also assess for:
- Wall motion (during or after an MI)***
- Calculate ejection fraction/systolic function***
- Eval size of heart chambers
- Assess diastolic function
- Evaluate valve structure and function***
- Detect tumors, masses, or clots in heart
List some factors that affect the results of a TTE (7)
- Chest wall abnormalities/trauma
- COPD
- Thick chest wall
- Excessive movement during exam
- Obesity
- Large breasts
- Posterior cardiac structure view
When is the most appropriate situation to utilize a TEE?
When higher resolution images of the POSTERIOR CARDIAC STRUCTURES are necessary
What is a TEE able to detect? (6)
- Clots (left atrial thrombi in pts with afib)***
- Septal defects or patent foramen ovale
- Ascending aortic atherosclerosis
- Aortic dissection
- Valvular pathology, such as vegetations in endocarditis***
- Better myocardial motion without as much interference
What are the contraindications for performing a TEE?
- Overall test has increased complications (requires cardiology and gas man team)
- Altered mental status
- Compromised cardiorespiratory status
- Recent or active esophageal tear or hemorrhage
- Coagulopathies
- Thrombocytopenia
- Esophageal stricture
What is the purpose of a cardiac stress test?
To monitor the heart’s ability to respond to external stress in a controlled environment
What are the 3 types of stress tests? Are they typically exercise or pharmacologically induced?a
- EKG stress test (exercise)
- Nuclear stress test (pharmacologic)
- Stress echocardiogram (pharmacologic)
What are the indications for cardiac stress tests? (3 main)
- Eval of exertional chest pain***
- Known CHD with new/worsening sx***
- Newly diagnosed heart failure or cardiomyopathy***
- Risk stratification of ischemic heart disease
- Determine exercise capacity
- Patients with prior coronary revascularization
- Pts with valvular heart disease
- Surgical clearance (non-cardiac)
What are the contraindications for any form of cardiac stress testing?
- Uncontrolled cardiac or vascular issue
- Aortic dissection
- Acutely ill
- Uncontrolled hypertension
Describe an exercise EKG stress test.
- EKG obtained at rest and monitored during exercise
- Patient exercises within protocol to achieve: target heart rate, symptoms, or time limit
What kind of stress testing can localize ischemia?
Cardiac stress testing with Imaging (exercise EKG unable to do this)
What are the 2 kinds of radioactive tracers used for nuclear stress testing? Where do they concentrate?
- Technetium-99m agents*** or Thallium
- Concentrate in areas of the myocardium with adequate blood flow and living myocardial cells (defect seen w/ hypoperfusion)
Name the 2 vasodilators and 1 inotrope used in nuclear stress testing.
Vasodilators:
- Adenosine
- Dipyridamole
Ionotropes:
-Dobutamine
What are indications for nuclear stress testing? (5)
- Pt has abnormal resting EKG (EKG stress test nondiagnostic for ischemia)
- Assess areas of myocardial ischemia
- Determine location and size of injured muscle after MI (1-2 months post MI)
- Diagnose coronary artery stenosis
- Eval how grafted vessels work post bypass surgery
What are the indications for a stress echocardiogram?
- Used in the dx of ischemia related to development of WALL MOTION ABNORMALITY with exercise/stress
- Known or suspected CAD
- Eval of CP, SOB, DOE
- Eval of valvular abnormalities
- Preoperative risk assessment prior to major surgery
What pharmacologic agent is often used with a stress echocardiogram?
Dobutamine (increases contractility and HR)
What are the indications for a Holter Monitor (ambulatory EKG)?
- Eval of syncope, PALPITATIONS
- Rhythm record
- Heart rate variability
- ST segment monitoring
What is the difference between a holter monitor and event monitor?
Both are ambulatory EKG monitors but holter monitors are continuous recordings while an event monitor is not (pt activates device indicating an event)
List the length of times a holter monitor, event monitor, and implantable monitor are typically used for.
Holter: 24-48 hours (best when they’re having daily sx)
Event: 30-60 days (best when sx are weekly-monthly)
Implantable: Up to 3 years (best for infrequent sx)
What is are the indications for use of an implantable cardiac monitor
- Pts with infrequent symptoms
- Pts with suspected arrhythmia but non-invasive testing has been negative or inconclusive
What is the primary indication for use of a fingertip monitor?
Best for monitoring arrhythmias (such as afib) that are symptomatic (essentially an at home EKG test for pts)
What are the 2 types of cardiac CT scanning and what are they used to detect?
- Coronary CT angiography (CCTA): Pt given contrast dye + CT; evaluates presence and extent of CORONARY ARTERY OCCLUSION
- Coronary CT calcium scan: No IV contrast given; assess for Ca2+ DEPOSITS IN CORONARY ARTERIES and therefore risk of MI
What are the major applications of a cardiac CT scan (in general)?
- Useful for evaluation of less mobile structures (like the thoracic aorta and pericardium as opposed to heart structures)
- Detection of AORTIC DISSECTION
- Detection of CORONARY ARTERY CALCIUM deposition (atherosclerosis)
- Detection of presence and extent of CAD
What are the contraindications for a cardiac CT scan?
- Allergy to contrast dye
- Severe renal insufficiency
What is the modality of choice for assessment of the functional and tissue properties of the heart?
Cardiac MRI
-Typically used for complicated and advanced disease patients, after eval with first-line testing, such as echocardiography
What are the indications for a cardiac MRI?
- Myocardial disease
- Valvular disease
- Pericardial disease
- Cardiac tumor
- CAD
- Myocardial perfusion
What are the contraindications for a cardiac MRI?
-Metal or electrical implants, devices, or foreign bodies
What is the gold standard for diagnosing CAD?
Cardiac catheterization/coronary angiography (pinpoints location and extent of occlusion)
What are the indications for use of cardiac catheterization/coronary angiography?
- Known/suspected CAD
- Atypical chest pain
- Before valve surgery in patient with chest pain or EKG changes
*Docs use this to put in balloons/stents
