General points
Syncopes affect a large population (13% to 40%). Not surprisingly, this impacts on their driving.
Syncopes affect a large population (13% to 40%). Not surprisingly, this impacts on their driving.
Syncope on road
In a large Danish study involving 4,139 patients with a 2-year follow-up, the occurrence of syncope was associated with an almost doubled accident risk. According to the study, 1,791 patients (4.4%) had a collision: 78.1% resulted in injuries and 0.3% resulted in death. Surprisingly, only a small portion of these accidents (349) were directly attributable to the driver’s syncope.1
A retrospective study on fainting while driving found that 30% of cases have a vasovagal origin, 25% supraventricular arrhythmia, 17% ventricular arrhythmia, 10% cardiac conduction abnormalities and 20% were undiagnosed.2
Vasovagal syncope is benign but recurring. Frequently preceded by prodromes, the driver would anticipate the accident by stopping the vehicle most of the time. However, in a study of 245 patients referred for suspicion of vasovagal syncope, 9% had experienced an event at the wheel, and a second one for a quarter of them. Despite the presence of prodromes in most patients, only nine injuries and one death were reported3
Cardiac arrhythmias often induced palpitations, dyspnea, chest pain and dizziness. A loss of consciousness is determined by the nature of the arrhythmia, the existence of underlying heart disease, and above all by individual susceptibility to sudden heart rate changes
The incidence of syncope indicates a patient’s poor tolerance to arrhythmia and its potential for recurrence. It contraindicates driving, at least temporarily.4
Most serious heart rhythm disorders (ventricular tachycardia, ventricular fibrillation, etc.) rapidly lead to death if they are untreated.
Fortunately, high-risk patients are protected by implantable defibrillators. Developed in the 1980s, these devices are widely used nowadays and convert a significant percentage of patients’ arrhythmias to normal heart rhythm by a rapid heart pacing or an electrical cardioversion.
Nevertheless, a small percentage of sudden death risk still exist:
- Faced with a refractory arrhythmia, the device would only deliver a limited number of therapies. If theses ones fail, the process is aborted.
- If arrhythmias are incessant or recurring despite effective therapies, the device’s battery ends up depleting.
- Even if treatment is prompt, syncope induced by the rhythm disorder may cause fatal trauma.
Most studies concluded the risk (based on the Canadian equation) as acceptable for patients implanted in primary prevention (identified before any rhythmic accident) for leisure driving. Driving prohibition is therefore limited to the post-operative recovery time (one week to one month).
For patients implanted after a rhythmic event, the results are contradictory. Learned societies have ruled on a ban of three to six months in Europe and the U.S.A.
Patients who have received a device appropriate therapy have a high risk of reoccurrence with two to four months, which justifies exclusion.5
If the fatality risk appears to be acceptable in these studies, it is because the results established the presence of syncope (occurring in 10% to 30% of cases) as the only cause of the accident.
However, the administration of therapy to a driver can destabilize them even without loss of consciousness. The studies of Mylotte et al. have prospectively followed 275 defibrillator carriers. Of these, 9.5% of them have developed pre-syncope and 3.3% (n=8) received a shock whilst driving, resulting in five accidents (out of a total of 14 collisions). Fortunately, no serious injuries nor deaths occurred, but as a matter of fact less than half of these accident victims had developed syncope prior to the crash.
The risk of shock while driving was calculated in this study at 1.5% per year but with an important bias: 9.1% of patients had stopped driving permanently and more than 30% limited their movements to what was strictly necessary after the device implantation…6
On the other hand, TOVA’s study has evaluated the occurrence of shock during and just after driving for two years in 1188 defibrillators carriers. The risk of needing a shock whilst driving was almost doubled when compared to the rest of the day. Seven appropriate shocks occurred while driving. None resulted in syncope, but one resulted in an accident.7
In a large Danish study involving 4,139 patients with a 2-year follow-up, the occurrence of syncope was associated with an almost doubled accident risk. According to the study, 1,791 patients (4.4%) had a collision: 78.1% resulted in injuries and 0.3% resulted in death. Surprisingly, only a small portion of these accidents (349) were directly attributable to the driver’s syncope.1
A retrospective study on fainting while driving found that 30% of cases have a vasovagal origin, 25% supraventricular arrhythmia, 17% ventricular arrhythmia, 10% cardiac conduction abnormalities and 20% were undiagnosed.2
Vasovagal syncope is benign but recurring. Frequently preceded by prodromes, the driver would anticipate the accident by stopping the vehicle most of the time. However, in a study of 245 patients referred for suspicion of vasovagal syncope, 9% had experienced an event at the wheel, and a second one for a quarter of them. Despite the presence of prodromes in most patients, only nine injuries and one death were reported3
Cardiac arrhythmias often induced palpitations, dyspnea, chest pain and dizziness. A loss of consciousness is determined by the nature of the arrhythmia, the existence of underlying heart disease, and above all by individual susceptibility to sudden heart rate changes
The incidence of syncope indicates a patient’s poor tolerance to arrhythmia and its potential for recurrence. It contraindicates driving, at least temporarily.4
Most serious heart rhythm disorders (ventricular tachycardia, ventricular fibrillation, etc.) rapidly lead to death if they are untreated.
Fortunately, high-risk patients are protected by implantable defibrillators. Developed in the 1980s, these devices are widely used nowadays and convert a significant percentage of patients’ arrhythmias to normal heart rhythm by a rapid heart pacing or an electrical cardioversion.
Nevertheless, a small percentage of sudden death risk still exist:
- Faced with a refractory arrhythmia, the device would only deliver a limited number of therapies. If theses ones fail, the process is aborted.
- If arrhythmias are incessant or recurring despite effective therapies, the device’s battery ends up depleting.
- Even if treatment is prompt, syncope induced by the rhythm disorder may cause fatal trauma.
Most studies concluded the risk (based on the Canadian equation) as acceptable for patients implanted in primary prevention (identified before any rhythmic accident) for leisure driving. Driving prohibition is therefore limited to the post-operative recovery time (one week to one month).
For patients implanted after a rhythmic event, the results are contradictory. Learned societies have ruled on a ban of three to six months in Europe and the U.S.A.
Patients who have received a device appropriate therapy have a high risk of reoccurrence with two to four months, which justifies exclusion.5
If the fatality risk appears to be acceptable in these studies, it is because the results established the presence of syncope (occurring in 10% to 30% of cases) as the only cause of the accident.
However, the administration of therapy to a driver can destabilize them even without loss of consciousness. The studies of Mylotte et al. have prospectively followed 275 defibrillator carriers. Of these, 9.5% of them have developed pre-syncope and 3.3% (n=8) received a shock whilst driving, resulting in five accidents (out of a total of 14 collisions). Fortunately, no serious injuries nor deaths occurred, but as a matter of fact less than half of these accident victims had developed syncope prior to the crash.
The risk of shock while driving was calculated in this study at 1.5% per year but with an important bias: 9.1% of patients had stopped driving permanently and more than 30% limited their movements to what was strictly necessary after the device implantation…6
On the other hand, TOVA’s study has evaluated the occurrence of shock during and just after driving for two years in 1188 defibrillators carriers. The risk of needing a shock whilst driving was almost doubled when compared to the rest of the day. Seven appropriate shocks occurred while driving. None resulted in syncope, but one resulted in an accident.7
References
- Nume AK, Gislason G, Christiansen CB, et al. Syncope and Motor Vehicle Crash Risk: A Danish Nationwide Study. JAMA Intern Med 2016;176:503-10.
- Blitzer ML, Saliba BC, Ghantous AE, Marieb MA, Schoenfeld MH. Causes of impaired consciousness while driving a motorized vehicle. Am J Cardiol 2003;91:1373-4.
- Li H, Weitzel M, Easley A, Barrington W, Windle J. Potential risk of vasovagal syncope for motor vehicle driving. Am J Cardiol 2000;85:184-6.
- Sorajja D, Nesbitt GC, Hodge DO, et al. Syncope while driving: clinical characteristics, causes, and prognosis. Circulation 2009;120:928-34.
- Thijssen J, Borleffs CJ, van Rees JB, et al. Driving restrictions after implantable cardioverter defibrillator implantation: an evidence-based approach. Eur Heart J 2011;32:2678-87.
- Mylotte D, Sheahan RG, Nolan PG, et al. The implantable defibrillator and return to operation of vehicles study. Europace 2013;15:212-8.
- Albert CM, Rosenthal L, Calkins H, et al. Driving and implantable cardioverter-defibrillator shocks for ventricular arrhythmias: results from the TOVA study. J Am Coll Cardiol 2007;50:2233-40.
