Device–Device Interaction Between Medtronic Sphere-9™ Ablation Catheter and Biotronik ICD/CRT-D Systems

Authors
Molly Sachdev, MD, MPH; Mina K. Chung, MD; Sana Al-Khatib, MD; Christopher F. Liu, MD; Lisa Miller, MS; Amit J. Shanker, MD

Correspondence
[email protected]

Summary

The Heart Rhythm Society (HRS) is notifying clinicians of a reported device–device interaction between the Medtronic Sphere-9™ ablation catheter and Biotronik implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) systems during radiofrequency (RF) energy delivery.

During RF energy delivery with the Sphere-9 catheter in patients implanted with Biotronik ICD or CRT-D systems, 33 cases of induced ventricular tachycardia (VT) and ventricular fibrillation (VF) have been reported as of February 20, 2026.  These events occurred during active RF delivery and terminated either spontaneously or with external defibrillation. To date, no deaths or permanent patient harm have been reported related to this interaction.

This device-device interaction results when RF current delivery from the Sphere-9 catheter activates a protective safety feature incorporated into Biotronik ICD and CRT-D systems.  Interaction has not been reported during pulsed field ablation (PFA) energy delivery using the Sphere-9 catheter.

Devices Affected

Ablation System

• Medtronic Sphere-9™ Ablation Catheter Model Number: AFR-00001

Implanted Cardiac Devices

• Biotronik ICD and CRT-D systems. No similar interaction has been observed with ICD or CRT-D systems from other manufacturers.

Clinical Issue and Patient Risk Considerations

As of February 20, 2026, a total of 33 incidents of VT or VF have been reported during RF energy delivery with the Sphere-9 Catheter in patients implanted with Biotronik ICD or CRT-D systems. Reported events occurred during energy delivery for cavotricuspid isthmus ablation in 22 cases, ventricular arrhythmia ablation in 10 cases, and ablation near a repaired mitral valve in 1 case. All ventricular arrhythmias occurred during active RF delivery and were successfully terminated, either spontaneously or with external defibrillation when required. Importantly, no deaths, permanent injury, or delayed adverse events have been reported. This interaction appears to be limited to the period of active RF delivery and has not been observed with pulsed field ablation (PFA) using the Sphere-9 catheter, nor has it been reported when the catheter is used in conjunction with ICD or CRT-D systems from manufacturers other than Biotronik.

Joint evaluation conducted by Medtronic and Biotronik determined that the observed interaction results from the specific RF current characteristics delivered by the Sphere-9 catheter interacting with a protective safety feature incorporated into Biotronik ICD and CRT-D systems designed to protect circuits from high voltage external signals, such as from cardioversion or MRI. This interaction may produce modulation by the Biotronik ICD or CRT-D of the coupled current into a 40 Hz signal which in turn may be conducted to the ICD tip electrode and precipitate ventricular arrhythmia induction. Neither manufacturer has identified evidence of hardware or software device malfunction, manufacturing defect, or design non-conformance in either the ablation catheter or the affected ICD or CRT-D systems.

The patient risk associated with this device–device interaction is procedural in nature and appears limited to periods of active RF energy delivery using the Sphere-9 Catheter in patients with implanted Biotronik ICD or CRT-D systems. Patients who may be at relatively increased risk include those implanted with a Biotronik ICD or CRT-D and undergoing cavotricuspid isthmus RF ablation, or those with defibrillation leads located in close proximity to the intended RF ablation site.  Importantly, available data demonstrate no evidence of long-term device damage from this particular interaction, persistent device malfunction, or clinically meaningful risk outside the procedural setting, and the observed risk appears confined to the intraprocedural period during RF energy application.

Medtronic and Biotronik are continuing joint evaluation of this interaction and will provide updates as additional clinical and bench-testing data become available.  HRS will update this advisory as new information emerges.

Manufacturer Recommendations

Medtronic US-based Instructions for Use already include the following procedural precautions when performing ablation using the Sphere-9 catheter in patients with ICD or CRT-D systems:

1. During a cardiac ablation procedure, life-threatening cardiac arrhythmias may be induced intentionally or unintentionally. Defibrillation equipment must be available for immediate use in the case of a life-threatening arrhythmia.
2. Exercise extreme caution when manipulating the catheter in close proximity to pacing and defibrillation leads to avoid damage or displacement of leads.
3. Do not deliver energy near other intracardiac devices or when in contact with other cardiac catheters or pacing and defibrillation leads to avoid possible unintended treatment application.

Medtronic has stated that updated labeling will be issued to include warnings specific to this device interaction when performing RF ablation using the Sphere 9 catheter in patients with Biotronik device.

HRS Recommendations

Before the Procedure

• Identify whether the patient has a Biotronik ICD or CRT-D system.
• Ensure external defibrillation equipment is applied and functional.
• Review procedural planning to minimize catheter proximity to ICD leads.
• As is standard with other RF and electrocautery procedures to direct the current path away from the ICD, place the return grounding pad/electrode away from the ICD, lower on the body.
• As is standard with all cardiac procedures involving energy delivery, it is advised to temporarily disable ICD tachy detection & therapy during an ablation procedure to minimize the risk of inappropriate therapies.
• Pacing function should be set as per patient needs, noting that energy delivery may cause oversensing and pacing inhibition.

During the Procedure

• Maintain heightened vigilance during RF energy delivery.
• Avoid delivering RF energy in close proximity to ICD coils when possible.
• Be prepared for immediate management of ventricular arrhythmias.
• Consider alternative energy modalities (including pulsed field ablation with the Sphere-9 catheter) or alternative RF catheter when clinically appropriate.
• Continue to follow institutional ICD management protocols during ablation.
• It is important to perform a complete implantable device check on all patients after ablation is completed.

Reporting & Support

Clinicians are advised to notify institutional risk management and device safety leadership of observed cases. Adverse events or observed device interactions should additionally be reported to:

FDA MedWatch
www.fda.gov/MedWatch

Phone: 1-800-FDA-1088

Medtronic Technical Support
Phone: 877-464-2796

FDA’s MedWatch
Adverse Event Reporting program either online, by regular mail or by fax.

• Complete and submit the report online
• Regular Mail or Fax: Download form or call 1- 800-332-1088 to request a reporting form, then complete and return to the address on the pre-addressed form or submit by fax to 1-800-FDA-0178.