Characteristics and analysis of right-to-left shunt-related dizziness in patients without hypoxemia

OBJECTIVE: This study aimed to analyze right-to-left shunt-related dizziness in three patients without hypoxemia. METHODS: Case 1 was a 47-year-old man with a history of cerebral infarction 8 years previously and recurrent dizziness for > 6 months. Patent foramen ovale (PFO) was found with a severe right-to-left shunt. Case 2 was a 50-year-old man with acute stroke. He had a history of repeated dizziness for > 4 years. He was diagnosed with PFO with a severe right-to-left shunt after admission. Case 3 was a 73-year-old woman with recurrent dizziness for > 10 months. Pulmonary arteriovenous fistula was diagnosed upon admission. No patients had hypoxemia. RESULTS: After percutaneous PFO occlusion in Cases 1 and 2, the patients were followed up for 6 months and 1 year, respectively. Two patients had relief of dizziness without recurrence. In Case 3, the pallor improved and the dizziness was relieved after pulmonary arteriovenous fistula embolization and did not recur over a 6-month follow-up. CONCLUSIONS: There was a possible association between a severe right-to-left shunt and dizziness, although hypoxemia was absent in the cases. Intervention to eliminate a left-to-right shunt can improve dizziness in patients without hypoxemia with a severe right-to-left shunt.