Software Monitoring Helps Detect ICD Malfunctions

A software-monitoring program that tracks implantable cardioverter-defibrillator (ICD) function could detect problems with the devices earlier than current monitoring processes, according to a new study.

Researchers at the Minneapolis Heart Institute Foundation (MN, USA) performed simulated prospective monthly full-cohort and propensity-matched comparative survival analyses on 3-center databases of the Sprint Fidelis--which was eventually recalled--and the Quattro Secure ICD, using a commercially available automated surveillance tool that was preset to detect early signals that an ICD was underperforming and trigger an alert if the log rank probability value was lower than 0.05. Patients in both databases had their ICDs implanted between 2001 and 2008.

The results showed that the surveillance software simulated and detected problems with the recalled leads at least a year before recall; in all, 84 of 1,035 Fidelis (8.1%) and 23 of 1,675 Quattro (1.4%) leads failed, with the simulated full-cohort analysis triggering a sustained alert for Fidelis leads beginning 13 months after the first implant, and two years before Fidelis leads were actually removed from the market. In the propensity-matched analysis, the alert triggered 22 months after the first Fidelis implant and more than one year before the lead was recalled. The study was published ahead of print on March 6, 2012, in Circulation.

"The software works; looking at ICD patients implanted years ago, we showed that the automated program detects medical device problems faster than current approaches,” said lead author consulting cardiologist Robert Hauser, MD. “Pinpointing the malfunction a year earlier in this case could have spared thousands of patients the health risks, costs and inconvenience of receiving a device prone to failure.”

ICDs monitor heart rhythms and deliver electric shocks to restore normal rhythm when life-threatening, irregular heartbeats occur. However, the surgically implanted devices can malfunction, particularly in the leads that connect them to the heart, causing injury or death. ICD manufacturers track repeated malfunctions and issue recalls if they are widespread, but by the time of the recall, thousands of the devices have usually already been implanted in patients.

Related Links:
Minneapolis Heart Institute Foundation