The Valuable Role of Cardio-Pulmonary Exercise Testing in the Diagnosis of Atrial Septal Defect in a Competitive Triathlete - A Case Report

Atrial septal defect (ASD) is characterized by a diverse clinical presentation influenced by the type, size, and hemodynamics. Endurance athletes with ASD may exhibit higher than normal performance levels, however they face an elevated risk of exercise-induced cardiac volume and pressure strain, potentially expediting a maladaptation of the right heart. An asymptomatic 28-year-old female elite triathlete sought a pre-participation sports medical examination. Her past medical history revealed right heart enlargement. Transthoracic echocardiography and magnetic resonance imaging did not ascertain a definitive diagnosis such as shunting. The examination revealed a remarkably high maximum oxygen uptake during cardio-pulmonary exercise testing (CPET), yet an abnormal oxygen uptake/workload slope and a low, plateauing oxygen pulse. The athlete agreed to transesophageal echocardiography which demonstrated a superior sinus venosus-type ASD. Surgical intervention, conducted with minimally invasive endoscopic robotic technology and a pericardial patch was performed at a tertiary center under full cardio-pulmonary bypass. At seven-month follow-up, the patient reported engaging in swim sessions without limitations and participating in high intensity cycling sessions with performances similar to pre-surgery. CPET revealed increased maximum oxygen consumption and normalization of oxygen uptake/workload slope and maximum oxygen pulse. Endurance athletes with ASD may have abnormal hemodynamic response during CPET despite an exceptional high maximum oxygen uptake. This underscores the value of CPET in the diagnostic work-up of right heart enlargement.