Cardiopulmonary Exercise Performance in Adults with Native Ebstein's Anomaly—A Comparison of Cyanotic versus Acyanotic Patients

Background: Oxygen saturation usually does not decrease during exercise. However, patients with Ebstein's anomaly (EA) with an atrial septal defect or persistent foramen ovale may desaturate during exercise. This study investigates the impact of cyanosis during exercise testing on peak oxygen uptake, oxygen pulse, and ventilatory efficiency. Furthermore, due to its additional impact on exercise capacity, lung function patterns were analyzed and associations calculated.

Method: From September 2001 to August 2021 a total of 121 adults (44.7 ± 14.5 years of age; range: 18.4–77.7) with native EA performed a cardiopulmonary exercise test with spirometry in advance. Oxygen saturations were measured by pulse oximetry. Statistics were performed with student's t-test.

Results: Out of 121 patients (pts), 27 (22%) had cyanosis either already at rest (11 pts; 9%, 82.0 ± 6.9 SpO₂%) or at maximal effort (16 pts; 13%, 93.1 ± 1.9 SpO₂% at rest and 81.4 ± 9.6 SpO₂% at maximal effort). Compared with acyanotic pts (n = 94, 78%) peak oxygen uptake (cyanotic vs. acyanotic: 17.3 ± 5.7 vs. 20.5 ± 6.9 mL/min/kg, p = 0.028 represented as 60.5 ± 17.9 vs. 75.1 ± 20.7% of predicted, p = 0.001), oxygen pulse (8.7 ± 3.0 vs. 11.1 ± 3.3 mL/heartbeat, p = 0.001), V’E/V’CO₂ slope (43.2 ± 13.8 vs. 31.6 ± 6.2 L, p < 0.001) and PETCO₂ (27.3 ± 7.1 vs. 33.5 ± 4.8, p < 0.001) were significantly impaired in cyanotic patients. Furthermore, the decrease in cyanotic patients was significantly higher (−11.5 ± 9.2% vs. −1.1 ± 2.4%, p < 0.001). Lung function patterns did not differ significantly.

Conclusion: In our patients with native EA, desaturation during exercise occurred in 13%, while 9% were already undersaturated at rest. While lung volumes, a correlator with exercise capacity, do not differ significantly, peak oxygen uptake is approximately 15% lower compared with those with normal oxygen saturation. Further studies should evaluate whether after surgical tricuspid repair, patients’ exercise capacity increases and whether desaturation at exercise or diminished exercise capacity should be a criterion to decide on the timing of surgery.

Publication History

Article published online:
12 February 2022