MerlinRecalls & reported problems across all models

We found 6 models of Merlin by St. Jude Medical, Inc. in the FDA's device registry (GUDID). Together they are named in 417 adverse event reports in the FDA's MAUDE database, received between Jul 10, 2018 and Aug 18, 2026 — classified as 1 death, 40 injuries, 376 malfunctions.

The most frequently reported specific device problem is “Incorrect Measurement” (237 reports).

8 FDA recall records name at least one of these models by its device identifier, 6 still open.

Reports come from manufacturers, hospitals and patients and are not verified by the FDA. A report does not prove the device caused the event. Widely used products collect more reports, so totals can't be used to compare products or estimate failure rates. Only reports that name a model's exact device identifier are counted. What reports can and can't tell you · How this data works

Merlin recalls

FDA recall records that name at least one of these models by its device identifier, newest first. Each recall usually covers specific models or lots, so check the details.

1. May 12, 2026Class IIOpen, Classified

   Software malfunction may occur during pacing capture threshold test of pacemaker resulting in programmer not successfully communicating the command to terminate the test.

   Z-2405-2026 · Root cause: Software Design Change · Recall details · FDA record ↗

2. Nov 21, 2024Class IIOpen, Classified

   Due to a programmer software anomaly, during finalizing of the leadless pacemaker system, a specific sequence of programmer actions combined with a loss of telemetry during a small window (<2 seconds) may cause the finalization step to fail. If this occurs, the Programmer displays a loss of telemetry detected window, and there is no pacing.

   Z-0753-2025 · Root cause: Under Investigation by firm · Recall details · FDA record ↗

3. Jun 17, 2022Class IIOpen, Classified

   The Merlin" 2 PCS model MER3700 is a portable, dedicated programming system designed to interrogate, program, display data from, and test Abbott Medical implantable medical devices during implant and follow-up.

   Z-1496-2022 · Root cause: Software design · Recall details · FDA record ↗

4. Jun 17, 2022Class IIOpen, Classified

   There is a potential for programmer software (Merlin PCS) and remote monitoring software application (Merlin.net) to display overestimated predicted battery longevity for certain pacemakers.

   Z-1495-2022 · Root cause: Software design · Recall details · FDA record ↗

5. Mar 10, 2022Class IIOpen, Classified

   Due to a programmer software anomaly under very specific circumstance when executing a pacing capture Decrement Test in-clinic on implantable cardioverter and cardiac resynchronization therapy defibrillator devices, the programmer may continue to execute the Decrement Test instead of terminating the test and restoring the permanent programmed pacing parameters.

   Z-0965-2022 · Root cause: Software design · Recall details · FDA record ↗

6. Mar 10, 2022Class IIOpen, Classified

   Due to a programmer software anomaly under very specific circumstance when executing a pacing capture Decrement Test in-clinic on implantable cardioverter and cardiac resynchronization therapy defibrillator devices, the programmer may continue to execute the Decrement Test instead of terminating the test and restoring the permanent programmed pacing parameters.

   Z-0964-2022 · Root cause: Software design · Recall details · FDA record ↗

7. Feb 28, 2020Class IITerminated

   Internal testing of software identified software anomaly scenarios where if non-applicable shock energy value is selected, the device will continue to use the previously programmed energy level and the user will not be alerted that the selected value was not retained.

   Z-1700-2020 · Root cause: Under Investigation by firm · names 2 of these models · Recall details · FDA record ↗

8. Apr 13, 2018Class IITerminated

   Devices inappropriately displayed a low battery indicator determined to be due to memory corruption.

   Z-0808-2020 · Root cause: Process control · Recall details · FDA record ↗

Most reported Merlin problems

Merlin models

6 models, most reported first. Each model has its own page with its reports, recalls and device details.

• Merlin™ 3650

  Defibrillator, automatic implantable cardioverter, with cardiac resynchronization (CRT-D)
  1 recall1 death380 reports
• Merlin™ 3330

  Defibrillator, automatic implantable cardioverter, with cardiac resynchronization (CRT-D)
  6 recalls0 reports
• Merlin™ MER3400

  Implantable cardioverter defibrillator (non-CRT)
  2 recalls0 reports
• Merlin™ EX3100

  Defibrillator, automatic implantable cardioverter, with cardiac resynchronization (CRT-D)
  18 reports
• Merlin™ 2

  implantable pacemaker Pulse-generator
  18 reports
• Merlin™ 3638

  Pulse generator, permanent, implantable
  1 report

Recent Merlin adverse event reports

The 15 most recent reports across all models, in the reporter's own words as published by the FDA.

• InjuryAug 18, 2026Adverse Event Without Identified Device or Use Problem

  It was reported that the patient experienced loss of capture in the ventricle during an atrial capture threshold test. As a result, the patient experienced asystole. No intervention was reported to resolve the event. Abbott Technical Support reviewed the device session records and stated the event was due to a normal device behavior during the atrial capture threshold test. The RV pulse amplitude automatically becomes the last programmed fixed pulse amplitude which fell below the capture threshold required to stimulate the patient. The patient was in stable condition.

  Patient problems: Arrhythmia

  MAUDE report 50308016 ↗
• InjuryJul 31, 2026Application Program Freezes or Fails to Launch

  It was reported that a programmer became frozen during the sense test for a right atrial (RA) leadless pacemaker (LP). The LP had been programmed to a lower pacing rate for the test and there was no way to end it or reprogram. The test was also unsuccessful as the LP failed to sense, which was the same result from implant. The programmer power supply was accidentally unplugged, but the RA LP was still set to the lower pacing rate and unable to sense. The programmer test was then successfully ended on its own. Patient was stable with no other symptoms.

  Patient problems: Arrhythmia

  MAUDE report 50107404 ↗
• MalfunctionJun 25, 2026Thermal Decomposition of Device; Failure to Power Up; No Apparent Adverse Event; Unexpected Shutdown

  THIS REPORT IS TO ADVISE OF AN EVENT OBSERVED DURING ANALYSIS.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 25627173 ↗
• MalfunctionJun 23, 2026Communication or Transmission Problem; No Tactile Prompts/Feedback

  DURING AN IN-CLINIC FOLLOW-UP, THE PROGRAMMER'S TOUCH SCREEN WAS RESPONSIVE BUT NOT FUNCTIONING CORRECTLY AND THE PROGRAMMER WASN'T PROGRAMMING THE DEVICE AS DESIRED. THE PROGRAMMER SWITCHED TO NO PACING MODE (ODO MODE) UNPROMPTED. THE PATIENT IS PACEMAKER DEPENDENT, HOWEVER NO ADVERSE EVENT OCCURRED. A DIFFERENT PROGRAMMER WAS USED TO PROGRAM BACK TO DESIRED SETTINGS. THE PATIENT WAS STABLE WITH NO CONSEQUENCES.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 25598577 ↗
• MalfunctionJun 11, 2026Device Emits Odor; Smoking

  THE HEALTHCARE PROVIDER ATTEMPTED TO TURN ON THE PROGRAMMER AND IT BEGAN TO SMOKE AND A BURNT SMELL WAS OMITTED. NO PATIENT WAS INVOLVED AND NO CONSEQUENCE TO THE HEALTH CARE PROVIDER.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 25466189 ↗
• MalfunctionMay 31, 2026Loose or Intermittent Connection; No Pacing

  IT WAS REPORTED THAT THE PATIENT PRESENTED FOR AN IMPLANT PROCEDURE. DURING THE PROCEDURE, IT WAS NOTED THE RIGHT ATRIAL (RA) LEAD HAD DISLODGED. THE DISLODGEMENT OCCURRED DURING STYLET REMOVAL AND WAS CONFIRMED INTRAOPERATIVELY UNDER FLUOROSCOPY IN THE CATHETERIZATION LABORATORY. AFTER DISLODGEMENT, THE LEAD WAS REMOVED ONCE, AND THE SCREW WAS CONFIRMED TO BE NORMAL. DURING A SUBSEQUENT ATTEMPT TO RE IMPLANT IN THE RIGHT ATRIAL APPENDAGE, PACING SYSTEM ANALYZER (PSA) MEASUREMENTS PRIOR TO SCREW FIXATION COULD NOT BE PERFORMED. UPON CONNECTING THE THRESHOLD CABLE, NO WAVEFORM WAS OBTAINED, AND NO PACING OUTPUT WAS OBSERVED. THE RA LEAD WAS SUSPECTED TO BE DAMAGED. THE RA LEAD IS NOT USED AND REPLACED. THE PSA WAS NOT USED. THE PATIENT WAS IN STABLE CONDITION THROUGHOUT THE PROCEDURE.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 25344454 ↗
• MalfunctionMay 12, 2026Unintended Electrical Shock

  IT WAS REPORTED THAT THE USER WAS SHOCKED BY THE PROGRAMMER. THERE WERE NO ADVERSE CONSEQUENCES AND THE USER WAS STABLE.

  Patient problems: Discomfort

  MAUDE report 25153417 ↗
• InjuryApr 20, 2026Interrogation Problem; Application Program Freezes or Fails to Launch

  IT WAS REPORTED THAT THE PATIENT PRESENTED POST IMPLANT PROCEDURE FOR FOLLOW-UP. UPON DEVICE INTERROGATION, THERE WAS I2P INTERRUPTION WHILE PERFORMING AN ATRIAL SENSE TEST. THE PROGRAMMER THEN FROZE AND HAD TO BE RESTARTED AS A RESULT. DURING THIS TIME THE PATIENT EXPERIENCED BRADYCARDIA FOR LONGER THAN EXPECTED. AFTER TURNING THE PROGRAMMER OFF AND THEN BACK ON THE PACING BASE RATES WERE SUCCESSFULLY RE-ESTABLISHED. THE PATIENT WAS IN STABLE CONDITION.

  Patient problems: Arrhythmia

  MAUDE report 24927920 ↗
• MalfunctionApr 13, 2026Incorrect Measurement

  IT WAS REPORTED THAT THE PROGRAMMER EXHIBITED AN INCORRECT LONGEVITY ESTIMATE BECAUSE OF A BATTERY LONGEVITY CALCULATION OVERESTIMATION. NO PATIENT COMPLICATIONS HAVE BEEN REPORTED AS A RESULT OF THIS EVENT.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 24867616 ↗
• MalfunctionApr 11, 2026Smoking; Excessive Heating

  IT WAS REPORTED THAT THE PROGRAMMER WAS EMITTING SMOKE. THERE WERE NO ADVERSE CONSEQUENCES.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 24847359 ↗
• MalfunctionApr 8, 2026Failure to Interrogate

  IT WAS REPORTED THAT THE PATIENT PRESENTED IN CLINIC FOR FOLLOW-UP. DURING THE VENTRICULAR CAPTURE TESTING, IT WAS FOUND THAT THE RIGHT VENTRICULAR LEADLESS PACEMAKER LOST ITS CONDUCTIVE TELEMETRY WITH THE PROGRAMMER AND RESULTED IN FAILURE TO CAPTURE. NO INTERVENTION WAS PERFORMED. PATIENT CONDITION WAS STABLE.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 24821453 ↗
• MalfunctionApr 8, 2026Interrogation Problem

  IT WAS REPORTED THAT THE PATIENT PRESENTED TO THE HOSPITAL FOR A LEADLESS PACEMAKER (LP) IMPLANT PROCEDURE. WHILE CONDUCTING A PACING CAPTURE THRESHOLD (PCT) TEST, TELEMETRY WAS LOST BETWEEN THE LP AND PROGRAMMER. THE CAPTURE TEST COULD NOT BE TERMINATED, AND THE PROGRAMMER WAS TURNED OFF. AFTERWARDS, IT WAS DIFFICULT TO RE-ESTABLISH TELEMETRY AND THE IMPLANT COULD NOT BE FINALIZED. IT WAS SUSPECTED THAT THE LOSS OF TELEMETRY WAS DUE TO NOISE INTERFERENCE FROM A PACING CATHETER WHICH WAS REQUIRED TO STIMULATE THE PATIENT WHO WAS PACEMAKER DEPENDENT. THE PHYSICIAN THEN REDUCED THE RHYTHM AND POWER FROM THE PACING CATHETER, AND THEY WERE ABLE TO RE-ESTABLISH TELEMETRY AND FINALIZE THE IMPLANT FOR THE LP. THERE WAS NO ADVERSE CONSEQUENCE TO THE PATIENT AND THE PATIENT REMAINED IN STABLE CONDITION.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 24821195 ↗
• InjuryMar 12, 2026Display or Visual Feedback Problem; Application Program Freezes or Fails to Launch; Program or Algorithm Execution Failure

  DURING AN IN-CLINIC CAPTURE THRESHOLD TESTING, THE USER RELEASED THE BUTTON TO TERMINATE THE TESTING AS EXPECTED, HOWEVER, THE PROGRAMMER SCREEN FLICKERED AND THE SOFTWARE FROZE WITH THE SUSTAINED DECREMENT, RESULTING IN LOSS OF CAPTURE, AND PATIENT SYNCOPE. SHORTLY, BACKUP PACING WAS ENABLED, AND THE PACING FUNCTION WAS RESTORED. PATIENT CONDITION WAS STABLE.

  Patient problems: Syncope/Fainting

  MAUDE report 24585984 ↗
• MalfunctionMar 11, 2026Noise, Audible; Unintended Electrical Shock

  IT WAS REPORTED THAT UPON SWITCHING THE PROGRAMMER ON, A CRACKLING SOUND WAS HEARD AND THE USER RECEIVED A SMALL ELECTRIC SHOCK FROM THE PROGRAMMER. NO CONSEQUENCES TO THE USER AND NO MEDICAL INTERVENTION WAS REQUIRED. THE PROGRAMMER WAS NO LONGER USED AND WAS REPLACED.

  Patient problems: Discomfort

  MAUDE report 24573176 ↗
• MalfunctionJan 7, 2026Data Problem; Application Program Freezes or Fails to Launch

  ADDITIONAL INFORMATION WAS RECEIVED INDICATING THE DEVICE WAS REPROGRAMMED. THE PATIENT WAS IN STABLE CONDITION.

  Patient problems: Arrhythmia

  MAUDE report 23987137 ↗

Other St. Jude Medical, Inc. products

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