Cardiac Imaging/ ECG Interpretation Flashcards
Indications:
Symptomatic patients: chest pain, palpitations, fatigue/sob, syncope, seizure
Evaluation/monitoring of: audible abnormalities (arrhythmia), suspected electrolyte imbalance, PE, congenital heart disorders, CHF, cardiomyopathy, poisonings/electrocution
Drug monitoring
Presence of implanted defibrillator/pacemaker
ECG (Electrocardiography)
Diagnose a myocardial infarction or potential of coronary artery disease
Detect arrhythmias
Pulmonary emboli
Detect enlargement of ventricles
Detect electrolyte disturbances
Detect drug effects on the heart
Diagnostic Uses of the EKG
Indications:
Diagnosis/assessment of arrhythmias
Symptoms suggestive of arrhythmia: unexplained syncope/near syncope, episodic dizziness, unexplained recurrent palpitations
Evaluate the effectiveness of arrhythmia therapy
Screen for asymptomatic arrhythmia in patients with high risk (i.e. cardiomyopathies, long QT syndrome, congenital heart disease)
Evaluate prognosis after ACS
Assess for silent ischemia in someone with known/suspected CAD
Ambulatory ECG Monitoring
Continuous ECG (Holter)
Event (loop) monitors
Patch Monitors
Mobile Cardiac Outpatient Telemetry (MOCT)
Insertable cardiac monitoring
Types of Ambulatory Monitoring
Best for patients with daily or near daily symptoms and/or if continuous monitoring of all cardiac activity is required
Daily palpitations or dizziness
Assessment of rate control in afib
Continuously records heart rhythm
Usually worn for 24 hours during normal activity
3-5 electrodes on the chest
Battery operated monitor
Patient keeps symptom diary for correlation to symptoms
Holter Monitor
Good for patients with slightly less frequent symptoms/need for longer monitoring
More convenient and easier for patient to tolerate than Holter
Small all in one device, no separate leads/wires or batteries
Record only a single lead but can record continuously for up to 30 days
3, 7, 14 or 30 days
Similar to MCOT which is 3 leads
Patch Monitor
Mobile Cardiac Outpatient Telemetry
Traditionally 3 leads but now available as 1 lead (patch)
Can be worn up to 30 days with continuous recording OR auto or patient triggered
Daily report transmitted wirelessly to central monitoring station for physician review
Can get real time (or close) interpretation
Good for those who require comprehensive assessment of all cardiac activity for longer periods – assessing arrhythmia burden, assessment of nocturnal arrhythmias etc
MCOT
May be needed if other event monitors can’t provide enough data
Size of a pack of gum
Can be programmed to record when patient activates it or when symptoms occur
Insertable Cardiac Monitor
Treadmill:
Bruce Protocol – most common in office based testing – extensively validated
Modified Bruce Protocol – can be used in patients unable to complete Bruce protocol
Bicycle
Stress Testing - Common Exercise Protocols
Stress radionuclide myocardial perfusion imaging (rMPI)
Single photon emission computed tomography (SPECT)
Can be used in exercise MPI or pharmacologic MPI
OR
Positron emission tomography (PET)
Generally only used in pharmacologic MPI
IV Radioactive tracer (Tc-99 technetium sestamibi) administered – wait 30-45 minutes – resting pictures taken
Exercise/stress starts – 2nd tracer administered – stress pictures taken
Total time 2-3 hours
Nuclear Imaging Stress Test (MPI)
SPECT images (single photon emission computed tomography) - gamma radiation is measured directly
Images after 30-45 minutes of rest are compared to stress images.
Nuclear imaging – “cold spot” areas are considered areas of low or no blood flow
Interpretation is based on the rest images
Reperfused (ischemic area), also called reversible defect
Fixed defect (infarct)
Nuclear Imaging Stress Tests
heterogeneous uptake radionuclide throughout the myocardium of the LV.
Cardiac Nuclear Scan normal finding
is the most accurate to determine coronary occlusive disease
Nuclear Scan
Cardiac Stress Test
normal finding: pt. able to maintain HR of 85% for predicted age and gender with no cardiac symptoms or EKG change
