AF Equipment Operation & Maintenance 3 — Questions and Answers
Question 1: In an electrophysiology lab performing AF ablation, the high-density mapping catheter is used primarily to:
- Deliver radiofrequency energy to pulmonary veins
- Create a 3D electroanatomic map of the left atrium (Correct answer)
- Monitor systemic blood pressure during the procedure
- Pace the atrium at fixed intervals for cardioversion
Correct answer: Create a 3D electroanatomic map of the left atrium
High-density mapping catheters collect electrogram data across multiple electrodes to build a 3D activation map guiding ablation strategy.
Question 2: Radiofrequency (RF) ablation catheters used for AF pulmonary vein isolation typically operate at a frequency of:
- 50–60 Hz (standard household current)
- 300–1,000 kHz (RF range) (Correct answer)
- 1–10 MHz (microwave range)
- 10–100 GHz (millimeter wave)
Correct answer: 300–1,000 kHz (RF range)
RF ablation operates in the 300–1,000 kHz range, generating resistive heating at the catheter tip to create a lesion.
Question 3: The primary safety advantage of cryoablation balloons over radiofrequency catheters for pulmonary vein isolation is:
- Faster lesion creation
- Reversibility of early freeze lesions before ice forms completely (Correct answer)
- Higher success rates in persistent AF
- No need for fluoroscopic guidance
Correct answer: Reversibility of early freeze lesions before ice forms completely
Early cryo application is reversible, allowing tissue assessment before a permanent lesion is formed, reducing risk of collateral damage.
Question 4: Contact force sensing ablation catheters improve AF ablation outcomes by:
- Automatically selecting energy output based on catheter position
- Providing real-time tissue contact force data to reduce gaps in lesion sets (Correct answer)
- Measuring intracardiac temperature at the ablation site
- Detecting pulmonary vein stenosis post-ablation
Correct answer: Providing real-time tissue contact force data to reduce gaps in lesion sets
Adequate and consistent contact force is critical to creating transmural lesions; force sensors provide feedback to prevent under-contact gaps.
Question 5: When the ablation generator displays an impedance rise ("impedance pop") during RF delivery, the clinician should:
- Increase power to overcome the impedance
- Immediately stop RF energy and reassess catheter position (Correct answer)
- Continue at current settings for 30 more seconds
- Switch to pacing mode
Correct answer: Immediately stop RF energy and reassess catheter position
A sudden impedance rise (pop) indicates char formation or steam pop at the catheter tip, which can cause perforation; energy must be stopped immediately.
Question 6: The irrigation flow rate of a cooled-tip ablation catheter is increased primarily to:
- Reduce thrombus formation and limit tip temperature rise (Correct answer)
- Increase the depth of the lesion by cooling surrounding tissue
- Flush contrast dye for angiographic imaging
- Maintain catheter stiffness during positioning
Correct answer: Reduce thrombus formation and limit tip temperature rise
Saline irrigation cools the catheter tip to prevent char and thrombus while allowing higher power delivery for deeper lesions.
Question 7: After an AF ablation procedure, the EP catheter introducer sheaths should be inspected for which critical maintenance concern before reuse or disposal?
- Discoloration of the plastic hub
- Integrity of the hemostasis valve to prevent air embolism (Correct answer)
- Presence of residual contrast dye
- Length measurement accuracy
Correct answer: Integrity of the hemostasis valve to prevent air embolism
A damaged hemostasis valve can allow air entry or uncontrolled bleeding; valve integrity must be verified before and after use.
AF Equipment Operation & Maintenance 3
In an electrophysiology lab performing AF ablation, the high-density mapping catheter is used primarily to: