Deaths Caused by the Failure of Riata and Riata ST Implantable Cardioverter-Defibrillator Leads

Study Questions:

Has failure of the Riata or Riata ST implantable cardioverter-defibrillator (ICD) leads been responsible for any deaths?

Methods:

A Food and Drug Administration database was queried to identify deaths that may have been caused by a Riata lead failure. A lead-related death was defined as sudden death accompanied by evidence of lead failure. Deaths in patients with a Quattro Secure ICD lead also were assessed.

Results:

The database search yielded 22 deaths related to failure of a Riata/Riata ST lead, and five related to a Quattro lead failure. The mean time of death after implantation was longer for Riata lead failures (61 months) than for failures of the Riata ST (36 months) and the Quattro (36 months) leads. Seven of the 22 Riata/Riata ST lead-related deaths were caused by an insulation defect in the pocket that resulted in a short circuit and failure to deliver therapy. None of the Quattro lead-related deaths were caused by an insulation defect. Thirteen Riata/Riata ST lead-related deaths were due to high-voltage conductor defects resulting in failure to defibrillate. Three Quattro lead-related deaths were due to pace-sense conductor failure, and two were due to high-voltage conductor defects.

Conclusions:

Insulation defects in Riata/Riata ST leads can result in death caused by failure of an ICD to defibrillate.

Perspective:

Electrical shorts can occur abruptly during shock delivery without any prior evidence of lead failure detectable by routine monitoring. During monitoring, all impedance vectors should be evaluated, and coil-to-can electrograms should be examined for artifacts that may be caused by a coil-to-can short. Because of the risk of failure to defibrillate, any evidence of Riata lead failure should prompt early replacement.

Keywords: Defibrillators, Death, Shock, Electric Impedance, Electric Countershock, Heart Rate, United States, Tachycardia, Artifacts


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