The valuable role of cardio-pulmonary exercise testing in the diagnosis of atrial septal defect in a competitive triathlete: a case report

BACKGROUND: Atrial septal defect (ASD) is characterized by a diverse clinical presentation influenced by the type, size, and haemodynamics. 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.

CASE SUMMARY: 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 transoesophageal echocardiography that 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 centre 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. Cardio-pulmonary exercise testing revealed increased maximum oxygen consumption and normalization of oxygen uptake/workload slope and maximum oxygen pulse.

DISCUSSION: Endurance athletes with ASD may have abnormal haemodynamic 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.