Recent ICD Implant Not a Risk for Car Crashes, but There Are Caveats
Due to uncertainty within the data, the impact of looser driving restrictions still merits close scrutiny, a researcher says.

Receiving an implantable cardioverter-defibrillator (ICD) within the last 6 months does not appear to increase a patient’s risk of serious motor vehicle accidents, though some degree of hazard cannot be definitively excluded, data out of Canada suggest.
A recent implant was not associated with a significantly greater risk of having a subsequent crash or, if one did occur, of being deemed responsible for that accident, researchers led by John Staples, MD (University of British Columbia, Vancouver, Canada), report in a study published online recently in JACC: Clinical Electrophysiology.
With so few ICD recipients included in the analysis looking at patients’ culpability, however, there was insufficient statistical power to exclude a potentially large increase in the likelihood of being blamed for an accident among patients who had a device.
The results “are all somewhat reassuring,” Staples told TCTMD, but because of the uncertainty in the data, the impact of less-stringent driving guidance for ICD recipients—as introduced in the past few years in Europe and Canada, for instance—should be closely monitored moving forward. “I think our study suggests that caution is needed . . . to make sure that the crash risk hasn’t increased,” he said.
Driving With an ICD
Ventricular arrhythmias, appropriate and inappropriate shocks, and complications like lead dislodgement are believed to occur more frequently in the first few months after ICD implantation, and if these occur while a patient is driving, they might cause an accident. For that reason, driving is typically restricted for a certain period of time after the implant, with longer periods of up to 3 to 6 months advised for those receiving a device for secondary prevention.
Though prior studies have examined the risk of car crash after ICD implantation, they have been subject to various limitations. Thus, the evidence that can be used to inform fitness-to-drive recommendations in this setting is not that strong, Staples said.
He and his colleagues sought to overcome some of the limitations of the existing evidence by taking advantage of large population-based administrative health and driving databases in the province of British Columbia. They identified all drivers who were involved in a serious motor vehicle accident between 1997 and 2019 and patients with an ICD implant in the prior 6 months.
A case-crossover analysis included 2,595 drivers (median age 66 years; 85% men) who were involved in 3,299 crashes during the study period. ICD implantation was recorded in 6.4% of precrash intervals and 7.4% of control intervals that didn’t involve an accident, indicating no significant association between device implantation and subsequent crashes (adjusted OR 0.86; 95% CI 0.71-1.03).
The researchers also performed an analysis of all drivers who were involved in a crash and had a responsible individual listed (the responsibility analysis eliminates total time spent driving as a potential confounder). Overall, 14 of 22 drivers who had recently received an ICD were deemed responsible for the crash, compared with 532,741 of 1,035,433 drivers without an ICD (64% vs 51%); the difference fell short of statistical significance (adjusted OR 2.20; 95% CI 0.94-5.30).
Our study suggests that caution is needed . . . to make sure that the crash risk hasn’t increased. John Staples
Based on these two analyses, “the mixture of driving restrictions, voluntary reductions in driving, and nonadherence to recommended driving restrictions all seem to generate crash risk that’s pretty similar to control groups,” Staples said. “And so that’s the reassuring finding overall, although it comes with a number of caveats.”
As with prior studies, it’s difficult to ultimately account for differences in the amount of time people spend driving. Staples noted that a prior study from his group showed that ICD recipients had a crash risk that was lower than that among controls. “But for a number of reasons, we think this is because many of those people either stop driving or reduce the amount of driving that they’re doing after the ICD is put in partly in line with recommendations from their physician,” he said.
It's important to determine the crash risk per hour of driving, Staples said, “because obviously we don’t want to reassure people falsely that their crash risk is ‘lower’ if indeed when they get behind the wheel their crash risk is dramatically higher than it would otherwise be.”
The responsibility analysis addresses this limitation to some extent because all drivers had been involved in an accident. Although there was no significant difference in crash responsibility between ICD recipients and controls, there was a numerical increase in being blamed for the accident in the ICD group.
“I think that number gives everybody a bit of pause,” Staples said, referring to the adjusted odds ratio of 2.20. “The challenge is that the confidence intervals on that were very wide and included perhaps a decreased likelihood of crash responsibility or a very large . . . fivefold increase in crash responsibility. So it’s hard to say with any confidence that the risk is not increased at all.”
What this indicates is that “there needs to be more research that maybe leverages technology to try to better establish the specific times when people are driving to account for that road exposure and maybe also uses technology to relate the crashes to cardiac events such as ventricular tachycardia, ventricular fibrillation, or shocks from the ICD,” Staples said.
And considering that post-ICD driving restrictions were loosened in Canada and Europe relatively recently, research is needed to ensure that crash risk has not gone up, he added. Staples stressed the importance of this research, which concerns clinicians, police, traffic safety professionals, and patients.
“In many prior studies, patients have identified driving restrictions as the worst aspect of having an ICD,” he said. “And clinicians have previously identified challenges with feeling confident about the driving restrictions that they’re recommending to patients. So this kind of cross-disciplinary work is just an important topic for both groups.”
Todd Neale is the Associate News Editor for TCTMD and a Senior Medical Journalist. He got his start in journalism at …
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Staples JA, Daly-Grafstein D, Robinson I, et al. Cardioverter-defibrillator implantation as a risk factor for motor vehicle crash. JACC Clin Electrophysiol. 2025;Epub ahead of print.
Disclosures
- The study was supported by the Heart and Stroke Foundation of Canada.
- Staples reports being supported by a Mentored Clinician Scientist Award from the Vancouver Coastal Health Research Institute and a Health Professional-Investigator Award from Michael Smith Health Research BC.
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