CMC Technology & Digital Tools 4 — Questions and Answers
Question 1: Which artificial intelligence application has received FDA clearance for detecting atrial fibrillation from a single-lead ECG signal in sinus rhythm?
- Apple Watch ECG algorithm using deep neural networks (Correct answer)
- Standard 12-lead ECG autoanalysis software
- Holter monitor beat-by-beat arrhythmia classifier
- Implantable loop recorder detection algorithm
Correct answer: Apple Watch ECG algorithm using deep neural networks
The Apple Watch ECG algorithm, developed with Mayo Clinic, uses deep learning to detect AF signatures even during sinus rhythm from a single-lead recording.
Question 2: In cardiac CT angiography, a coronary calcium score (Agatston score) of 400 places a patient in which cardiovascular risk category?
- High risk, equivalent to a CHD risk event rate >2% per year (Correct answer)
- Low risk, suitable for primary prevention without statin therapy
- Intermediate risk requiring stress testing for further stratification
- Very low risk where statin therapy can be safely withheld
Correct answer: High risk, equivalent to a CHD risk event rate >2% per year
An Agatston score >300–400 indicates extensive calcification and places patients in a high-risk category warranting intensified preventive therapy.
Question 3: A biventricular pacemaker used for cardiac resynchronization therapy (CRT) improves cardiac output primarily by:
- Coordinating simultaneous right and left ventricular activation to reduce dyssynchrony (Correct answer)
- Increasing heart rate to optimize cardiac output
- Providing backup pacing for complete heart block
- Overdrive pacing to suppress ventricular ectopy
Correct answer: Coordinating simultaneous right and left ventricular activation to reduce dyssynchrony
CRT resynchronizes dyssynchronous ventricular contraction in LBBB, improving stroke volume and reducing mitral regurgitation.
Question 4: Transesophageal echocardiography (TEE) probe cleaning between cases MUST follow which disinfection level to prevent transmission of pathogens?
- High-level disinfection (HLD) using glutaraldehyde, ortho-phthalaldehyde, or hydrogen peroxide (Correct answer)
- Intermediate-level disinfection with alcohol wipe
- Low-level disinfection with quaternary ammonium compounds
- Sterilization by autoclaving at 134°C
Correct answer: High-level disinfection (HLD) using glutaraldehyde, ortho-phthalaldehyde, or hydrogen peroxide
TEE probes are semi-critical devices requiring high-level disinfection per CDC and AIUM guidelines to eliminate all microorganisms except bacterial spores.
Question 5: Which hemodynamic parameter is measured by a thermodilution pulmonary artery catheter (Swan-Ganz) that cannot be obtained by echocardiography alone?
- Cardiac output measured by thermodilution with cold saline injection (Correct answer)
- Left ventricular ejection fraction
- Mitral valve area by pressure half-time
- Pulmonary artery systolic pressure estimate
Correct answer: Cardiac output measured by thermodilution with cold saline injection
Thermodilution cardiac output requires a PA catheter for cold injectate delivery and thermistor measurement, which cannot be replicated non-invasively by echo.
Question 6: A pacemaker programmed in DDD mode with a lower rate limit of 60 bpm and upper tracking limit of 130 bpm will behave how during sinus tachycardia at 150 bpm?
- Track at 130 bpm maximum, then apply Wenckebach-type upper rate behavior (Correct answer)
- Track the native rate of 150 bpm without limit
- Switch to VVI pacing at the lower rate limit of 60 bpm
- Deliver asynchronous pacing at 75 bpm regardless of native rate
Correct answer: Track at 130 bpm maximum, then apply Wenckebach-type upper rate behavior
When atrial rate exceeds the upper tracking limit in DDD mode, the device responds with Wenckebach upper rate behavior, dropping some P-waves.
Question 7: Quantitative flow ratio (QFR) is a novel catheterization laboratory technology that estimates FFR by:
- Computational fluid dynamics applied to 3D coronary reconstruction from biplane angiography without a pressure wire (Correct answer)
- Intravascular pressure wire measurement at rest without adenosine
- Doppler flow velocity integrated over the cardiac cycle
- Optical coherence tomography-derived lumen area calculation
Correct answer: Computational fluid dynamics applied to 3D coronary reconstruction from biplane angiography without a pressure wire
QFR uses 3D coronary reconstruction from two angiographic projections combined with fluid dynamics modeling to compute a virtual FFR without a pressure wire.
CMC Technology & Digital Tools 4
Which artificial intelligence application has received FDA clearance for detecting atrial fibrillation from a single-lead ECG signal in sinus rhythm?