New Research on ICDs with Regards to Sports Participation, High Altitudes, and Driving: Interview with Richard Kobza, MD

A recent survey in Switzerland shows that ICD patients can be encouraged to continue leisure-time physical activities at a low-to-moderate intensity level. In addition, the same research shows that high altitudes and driving are not often associated with ICD shocks. Lead author Dr. Richard Kobza, from the Division of Cardiology, Cantonal Hospital in Luzern, Switzerland, discusses his research.¹

What made you decide to study this population of ICD patients and these specific lifestyle factors? There is substantial evidence that patients with ICDs experience psychological distress, and we as treating physicians are regularly confronted with questions concerning possible limitations of lifestyle. Effects of exercise training in patients with ICDs have been studied and recommendations on sports participation among ICD patients published previously. However, there is limited information about the sports activities of these patients. Another question frequently posed by ICD patients is whether they may stay in the mountains, but little is known about the behavior of ICD patients during high-altitude stays. Tell us about the study, including how many ICD patients were followed, where the patients were located, and what the age range and gender of the patients were. A survey was performed in 387 patients with ICDs who were followed at two hospitals in Switzerland (Lucerne and Zurich). The specially-designed questionnaire addressed lifestyle practices concerning sports activity, high-altitude visits, and driving motor vehicles. The mean age of the 276 patients who provided information was 65 years (range 25–86); 81% were male. They were ICD carriers for 65 ± 40 months.

What were some of the questions included on the questionnaire? Some of the questions included: • How often did you perform sports before ICD implantation? • How often have you performed sports after ICD implantation? • Have you ever experienced an ICD shock during exercise? • Have you ever experienced an ICD shock during a high-altitude stay in the mountains? • What was your highest altitude stay since you are an ICD carrier? • Did you experience an ICD shock while you were driving?

How many patients reported participating in sports activities? Prior to ICD implantation, 69% of the patients did participate in sports activities; after ICD implantation, 59% were active in any sport.

Which sports or activities did they list? Sports and activities included biking/hometrainer (43%), hiking/nordic walking (31%), swimming (20%), skiing (18%), jogging (11%), gymnastics (7%), soccer (4%), and tennis (3%).

How many experienced an ICD shock during the activity? Seventeen percent of the 161 patients who regularly performed sports after ICD implantation experienced an ICD shock during sports activity. Most reported that the sports during which they received ICD shocks were biking (33%), skiing (18%), and hiking/jogging (13%).

Did high altitude have any negative effect on the patients who were studied? Has high altitude been shown to cause shocks in ICD patients? About 56% of the patients in our study reported a high-altitude stay above 2,000 m since having received their ICD, but only 4% experienced an ICD shock during the stay. Eleven percent of the patients even regularly stayed above 2,500 m. Our findings should help to reassure the patients that having an ICD does not disqualify them from going up into the mountains. However, since our findings are only observational, we cannot conclude that high-altitude stays do not trigger malignant arrhythmias and subsequent ICD therapy.

How many patients reported driving? Most patients continue to drive after ICD implantation; in our study, 85% and 79% of the patients drove a motor vehicle before and after ICD implantation, respectively. The concern is loss of consciousness and traffic accidents due to ICD shocks. In our study, 2% of the patients experienced an ICD shock during driving, but none of them reported loss of consciousness or a traffic accident.

Were any of the patients discouraged from these activities (sports, driving, or spending time in higher altitudes)? This study provides some information that implantation of an ICD per se should not lead to an impaired quality of life or an enforced restriction of leisure-time activities. Treating physicians may assure ICD patients to continue sports with a low to moderate activity level, as well as assure them that the ICD does not prevent them from going up into the mountains. However, these are not general recommendations — instead, every patient should be advised individually by his or her physician.

Were you surprised by these findings? The most surprising finding for me was that most of the patients continued going up in the mountains despite their heart disease. However, in Switzerland, it is common to spend leisure time in the mountains; therefore, people with ICDs do not want to change their habits after ICD implantation.

Is this study part of ongoing research? Will further research into this topic be done? Indeed, prospective studies are needed to confirm the safety of sports and the effect of high altitude on arrhythmogenesis.

¹Kobza R, Duru F, Erne P. Leisure-time activities of patients with ICDs: findings of a survey with respect to sports activity, high altitude stays, and driving patterns. Pacing Clin Electrophysiol 2008;31:845-849.