Provoked exercise desaturation in patients with patent foramen ovale, infrequent or underdiagnosed?

Abstract

To the Editor, The patent oval foramen (PFO) is present in nearly 1 out of every 4 people, and for the vast majority of them, it has no clinical implications.1 In others, however, it can trigger strokes, migraines or the orthostatic decompression or desaturation syndrome (known as platypnea-orthodeoxia syndrome).2 An even rarer presentation of PFO that can occur in the adult age is exercise-induced desaturation, which has been described in very few literature reviews and with a term not fully coined.3,4 This is the case of a 79-year-old woman with a past medical history of hypertension and diabetes referred to the cardiac rehabilitation unit due to dyspnea and poor functional capacity. The patient had previously undergone various tests including transthoracic echocardiography, pulmonary function tests, computed tomography pulmonary angiography, and coronary catheterization, all of which showed no significant findings. The physical examination revealed oxygen saturation levels around 98%, blood test results were normal, and N-terminal pro-brain natriuretic peptide levels, 255 pg/mL. Atthe office, she complained of exertional dyspnea that had just appeared after walking from the waiting room to the office. Then, a pulse oximeter was placed on her, and she was told to go for a walk. Oxygen saturation progressively dropped down to...