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