Does lifetime sports participation increase the risk of having a pacemaker installed due to bradycardia?

Introduction Traditionally, sinus bradycardia and AV block in athletes have been associated with vagus nerve activity. It is known that exercise can cause a decrease in the density of key ionic currents involved in the generation and conduction of impulses in the heart. This remodeling can persist over long periods of time, exacerbating age-related intrinsic dysfunction. The purpose of our study was to examine the characteristics of former professional athletes with a pacemaker due to idiopathic SA and AV node dysfunction, compared with a sedentary control group. Methods 18 former professional athletes (9 men, 9 women, mean age 69±13 years), group 1. Of these, 9 were involved in endurance sports (endurance subgroup), 9 were engaged in strength disciplines, strength subgroup. The control group consisted of 343 patients, of which 20 people had idiopathic dysfunction of the sinus and/or AV node (10 men, 10 women, 75.2±10.4 years, group 2). 323 patients (182 men, 141 women, 75.0±11.4 years) had various cardiac pathologies and made up the 3rd group. Clinical data, anamnesis, Holter monitoring, and echocardiography were analyzed. Results The age of diagnosis of SA or AV block and pacemaker (PM) implantation was significantly higher in the strength subgroup of group 1 compared to the endurance subgroup (72.4±9.5 and 64.0±7.5 years, p<0.01; 68 .5±13.0 and 65.0±11.7 years, p<0.05). The prevalence of AV block was higher in the endurance subgroup (78%) compared to the strength subgroup (48%), p < 0.05. At the time of implantation, the average age in the strength subgroup and group 2 did not differ (73.0±10.3 and 75.2±8.3 years, p>0.05), but was significantly lower (65.0±11.7 years, p<0.01) in the endurance subgroup. The age of PM installation in group 3 was lower than in groups 1 and 2 (72.4±7.4 and 75.2±8.3 years, p<0.05; 72.4 and 68.5±13.0 years, p<0.01, respectively). Other clinical characteristics did not differ between individuals in groups 1 and 2. The role of sports activities is evidenced by the correlations obtained for group 1 between the age of onset of first complaints (46.7±16.3 years), diagnosis (65.0±9.3 years), age of PM installation (68.5±13.0 years) and duration of sports in years (12.3±6.2 years), r=0.3, r=0.5, r=0.5 at p<0.05, respectively. A correlation coefficient was obtained between the age of stopping sports (25.2±7.5 years) and installation of PM (68.5±13.0 years) r=0.3 at p<0.05. Conclusions former professional endurance athletes with idiopathic SN dysfunction/AV block manifested the disease earlier in the life course compared to former power/mixed athletes and non-athletes. The nature and duration of sports play an important role in the formation of SA and AV conduction disorders. This suggests that bradycardia/AV block caused by intense and prolonged endurance sports may not always be a benign and adaptive phenomena.