The implantable cardioverter-defibrillator (ICD) improves survival in patients who have been resuscitated from ventricular fibrillation or unstable ventricular tachycardia (ie, secondary prevention of sudden cardiac death). Compelling data indicate that the ICD is also effective in the primary prevention of sudden cardiac death (SCD) in select high risk patients. (See "Overview of sudden cardiac arrest and sudden cardiac death".)
Most ICD candidates are ambulatory and appear well enough to drive an automobile. However, due to the risks of ventricular arrhythmias and ICD shocks, there are concerns about the risks associated with driving in this population. This topic will review issues related to driving in patients with an ICD.
CONCERNS WITH DRIVING
Concerns about driving center on the risk of symptomatic ventricular tachyarrhythmias and/or ICD discharge. More specifically, the risks associated with driving are based upon the likelihood that such events could impair consciousness and the patient's ability to control the vehicle. Driving, therefore, carries risk for the patient, other occupants of the vehicle, and persons outside of the vehicle. The extension of risk to others makes this issue a public health concern. Data regarding the risks associated with driving with an ICD are primarily retrospective, with no prospective trials that have randomized patients to driving with or without restrictions, and recommendations are based primarily on expert opinion and public policy.
Mechanisms of risk — Both ventricular arrhythmias and the actions of the ICD itself can potentially interfere with driving by several mechanisms:
- Sudden cardiac death – Although ICDs improve survival, they do not entirely eliminate the risk of sudden cardiac death (SCD). Data from major trials indicate that the rate of SCD among patients who receive an ICD for secondary prevention is one to two percent per year [1-3]. Similar or slightly lower SCD rates have been reported in major primary prevention trials [4-6].
- Syncope – Even rapid treatment of a ventricular arrhythmia by an ICD may not protect against driving impairment, since syncope or altered states of consciousness can still occur. In a review of 421 ICD patients, for example, syncope occurred in approximately 15 percent . (See 'Syncope' below.)
- Transient incapacitation from the shock – Even if therapy is successful and the patient remains conscious, the discomfort from an ICD discharge, either appropriate or inappropriate, may startle or briefly incapacitate the patient and disrupt safe motor vehicle operation.