Recurrent cardiac events in survivors of ventricular fibrillation or tachycardia: implications for driving restrictions

Survivors of ventricular fibrillation (VF) or ventricular tachycardia (VT) should not drive during the month following hospital discharge, and most VF and VT survivors should not consider driving for eight months after discharge. VF and VT are both forms of arrhythmic disorders of the heart and often result in a loss of consciousness and death. A study of 501 survivors of arrhythmic episodes, 290 with VT and 211 with VF, was conducted to determine when and if the risk of future arrhythmic episodes becomes low enough to allow the survivors to drive. The chances of experiencing an episode that would make operating a motor vehicle dangerous declined over the course of a year, and could be grouped into three periods. Survivors had a 4.22% hazard rate during the first month, a monthly rate between 1.4 and 2.2% in months 2 through 7, and a monthly hazard rate between 0 and 1.2% for months 8 through 12. The hazard rates were shown to be higher for VT survivors than for VF survivors, and patients with ejection fraction less than 0.40 (P
Objective. - To determine when survivors of ventricular tachycardia (VT) or ventricular fibrillation (VF) might most safely return to driving. Design. - Consecutive case series of 501 VT and VF survivors discharged alive between August 1978 and October 1989 and followed from 0 to 117 months (mean, 26 months). Setting. - Cardiac arrhythmia service of a university hospital. Patients. - The study group comprised 290 consecutive patients with sustained VT and 211 patients with VF who underwent electrophysiological studies and were discharged alive (78% male; mean age, 59 years). The mean ejection fraction (available in 338 patients) was 0.42. Interventions. - Antiarrhythmic drug testing for all patients was guided by serial electrophysiological testing. Overall, 227 patients (45%) were discharged on conventional antiarrhythmic agents, 115 (23%) on amiodarone, 39 (8%) received an implantable defibrillator, and 120 (24%) received no specific antiarrhythmic therapy. Main Outcome Measures. - Main outcomes included any event that could hamper a patient's ability to operate a motor vehicle. Specifically, these events included recurrent VF, poorly tolerated, hemodynamically unstable VT, syncope, sudden cardiac death, and implantable defibrillator discharge. Results. - Event risks were assessed during the first year after hospital discharge because that is when most patients decide whether to begin driving again. The 1 -year outcome event rate for all 501 patients was 17%. Three distinct periods of risk were identified. The monthly hazard rate was highest in the first month after hospital discharge (4.22% per month), intermediate in months 2 through 7 (1.81% per month), and lowest in months 8 through 12 (0.63% per month). The 191 patients for whom no successful conventional antiarrhythmic drug could be found during electrophysiological testing experienced a persistently high monthly event risk (1.6%) during months 8 through 12. Conclusions. - All survivors of VT or VF should refrain from driving during the first month after hospital discharge when the hazard for events that could impair their ability to drive is greatest. Our data would support restricting driving for most patients until the eighth month after hospital discharge, when risk becomes lowest. Restriction might be lengthened in patients for whom electrophysiological testing finds no satisfactory conventional antiarrhythmic agent because their risk remains higher than average even after 7 months. Individualized recommendations should be allowed because the accident rate for patients who actually suffer sudden death is low.