Automobile Driving After Life-Threatening Ventricular Tachyarrhythmia

Abstract & Commentary

Synopsis: Patients after recovery from a life-threatening arrhythmia are not at higher risk for motor vehicle accidents.

Source: Akiyama T, et al. N Engl J Med. 2001;345: 391-397.

Akiyama and colleagues from the antiar-rhythmics Versus Implantable Defibrillators (AVID) Trial studied the driving habits of patients enrolled in the study. AVID was a randomized trial that compared antiarrhythmic drug therapy to defibrillator therapy in patients who had survived a cardiac arrest or an episode of hemodynamically unstable ventricular tachycardia. Questionnaires about driving habits were sent a median of 9 months (range, 1-55 months) after the patient had been enrolled in the study. Questionnaires were sent to patients in both the drug treatment and the ICD treatment arms. Questionnaires were sent from the coordinating center and respondents were assured of anonymity.

There were 1016 patients enrolled in the AVID trial, but 107 (11%) died before the initial driving questionnaire was sent. The initial questionnaire was completed by 83% of those to whom the survey was mailed. Of the 758 patients who responded to the initial questionnaire, 627 (83%) had been driving during the year before their enrollment in the trial. Among these 627 patients who form the subject of this report, there were 537 men and 90 women who were 64.5 ± 10.1 years of age. Subsequent questionnaires were sent every 6 months to these patients. About 80% of patients returned each questionnaire.

Patients could recall that their physicians discussed driving restrictions with them 54% of the time. However, the recommendations they reported were variable. Forty-five percent of the patients, however, reported that their physician recommended that they not drive for at least 3 months. Patients reported that being restricted from driving was a severe hardship 59% of the time, and 35% of the patients reported that their household included no other drivers.

After enrollment, 57% of the patients had resumed driving within 3 months, 78% within 6 months, and 88% within 12 months after randomization. Most of the drivers reported driving the same amount as they had in the previous year with only one third reporting driving less. Most driving was for personal pleasure or errands rather than for job-related matters. Only 25% drove more than 100 miles per week.

Patients who had resumed driving were questioned regarding possible arrhythmia-related symptoms that occurred while driving. Loss of consciousness while driving was reported by 2%, 11% reported dizziness or palpitations that necessitated stopping the automobile, and 22% reported dizziness or palpitations that did not require them to stop. Of the 295 patients who had received an implantable cardioverter defibrillator, 8% reported receiving a shock while driving. Fifty patients reported having had at least 1 motor vehicle accident. In only 6 of 55 reported, accidents with symptoms of possible arrhythmia were associated with the accident. None of the accidents were preceded by an ICD shock. No patient in the study died because of an automobile accident. Possible injuries to others were not described. The annual risk of a motor vehicle accident was 3.4%. Interestingly, 6.2% of the patients reported having a motor vehicle accident during the year before their enrollment in the trial. Accidents occurred at a steady rate over time. There was no relationship to the period of time the patient had abstained from driving after AVID enrollment to his risk of having an accident. This accident rate was compared to that of the general US population (7.1%) and the rates were not significantly different.

Akiyama et al conclude that their data show that patients after recovery from a life-threatening arrhythmia are not at higher risk for motor vehicle accidents. They recommend that guidelines be changed to permit driving as soon as a patient’s associated medical conditions allow.

Comment by John P. DiMarco, MD, PhD

Many patients consider driving to be an important part of their lifestyle. Except in major cities, public transportation is often inadequate or inconvenient and driving forms an important role in maintaining the patient’s independence. In rural areas, a patient who cannot drive is virtually homebound unless relatives or friends can assist him. Society, however, has the responsibility to restrict those with obvious physical disabilities from driving in order to promote public safety. The study by Akiyama et al offers some insight into this problem.

It has also been in my experience that patients return to driving as soon as they feel physically able, even if their physician recommends against it. In my own practice, ICD or ventricular tachycardia patients will frequently arrive for their first follow-up visit after discharge having driven by themselves from a nearby town. All of these patients had been told about the current American Heart Association recommendations that restrict driving for several months after an episode of arrhythmia.

Unfortunately, the paper by Akiyama et al may not give the most accurate picture possible. This is due to the design of this retrospective study. First, it must be remembered that in AVID, patients had to be eligible for either drug therapy or an ICD. This meant that patients with frequent arrhythmia recurrences who required drug therapy to decrease the frequency of events were ineligible for the study. These patients with frequent episodes are the ones that physicians would most strongly counsel to avoid driving and these patients would presumably be at the highest risk for accidents. Second, 11% of the patients enrolled in the AVID trial died before they received the initial driving questionnaire. Once again, these were probably the sickest patients who were most at risk for recurrent arrhythmias. Extending conclusions based on data from healthier patients may not be justified. Finally, some of the patients in the AVID trial presumably had long-term disabilities related to complications of their resuscitation. Even minor motor or cognitive deficits might make it unsafe for an individual patient to drive.

Physicians counseling patients who resume driving should be aware that the highest risk of an unstable arrhythmia occurs during the first several months after the initial event. It is during that time period that antiarrhythmic therapy can be specifically tailored to the individual, if necessary, to decrease the frequency of symptoms. Therefore, I think that some period during which patients should be advised not to drive is still appropriate. I personally recommend at least 3 months even though this does cause some patients hardship.