T-wave alternans presence in young competitive athletes — to be or not to be accepted as a prognostic factor?

Objective We analysed the prevalence of TWA during cardiopulmonary stress test (CPT) in athletes and in patients with suspected or proven coronary artery disease with stress electrocardiographic test. Materials and Methods Athlete's group comprised 414 subjects (24±8 years, 95.5% males), non-athlete's — 107 (63±10 years, 42% males). Stress testing lasted longer and heart rate (HR) increased more in athletes compared to non-athletes. A TWA cluster was defined in case of uninterrupted appearance of TWA > 30 seconds. Results Our initial analysis revealed higher prevalence and worse parameters of TWA in athletes compared to non-athletes: at least one TWA cluster in 389 athletes (94.0%) and in 56 (52.3%) non-athletes, p<0.001. When we considered TWA-HR relationship and limited our TWA analysis to HR-range common to the two groups (80–125 bpm), our results changed significantly, with lower TWA prevalence in athletes than in non-athletes: 50 (12.1%) vs 46 (42.9%), p<0.001. Conclusion TWA is a HR-dependent parameter and athletes achieving high HR during CPT have an increased prevalence of TWA. Therefore, the prognostic significance of exercise-induced TWA in athletes could not be the same as that of TWA in high-risk non-athletes, where TWA appears in a lower HR range.