The Relationship Between Patent Foramen Ovaleand Unexplained Dizziness

Objective:Patent foramen ovale(PFO)is potentially associated with abnormal embolisms,and it results in mixing of arteriovenous blood when its right-to-left shunt(RLS)emerges.Present studies have found that PFO is a risk factor that can lead to many diseases.However,few studies have examined the relationship between PFO and dizziness.Methods:This study was a large single-center,controlled study.From March 2019 to March2021,we recruited patients with dizziness were divided into two groups: “explained”and “unexplained”.All patients were submitted to contrast-enhanced transcranial Doppler ultrasound and screened for PFO.Transesophageal heart ultrasound or right heart catheterization was used to confirm PFO.Additionally,multiple factors were collected and statistical analysis was performed between the two groups.Results:1、Basic information:Among the 244 patients included,123 were in the “explained” group and 121 were in the “unexplained” group.The prevalence of PFO in the “explained” group was 34(27.4%)compared to 79(64.7%)in the “unexplained” group.The average age of the unexplained dizziness group was 49.74 ± 15.19 years old,with 57 males(47%)and 64females(53%).The average age of the control group was 56.22 ± 12.16 years old,with62 males(50%)and 61 females(50%).The average age of patients in the " explained" group was 56.22 ± 12.16,and that in the "unexplained" group was 49.74 ± 15.19(P<0.001).There was no statistical difference between the two groups in gender.2、Analysis of related factors of dizziness.The risk factors related to dizziness were included,including diabetes,hypertension,coronary heart disease,arrhythmia,hyperlipidemia,BMI,LDL,TG,HCY,previous history of thrombosis,smoking,drinking,and history of mental illness.No statistical difference was found between the two groups after analysis of the above factors.3、Incidence rate of patent foramen ovale analysis:⑴ Compared with the explained dizziness group,the incidence rate of PFO in patients with unexplained dizziness was higher(64.7% vs 27.4%),which has statistical significance(P<0.001).⑵ Massively shunted PFO showed more pronounced risk factors(OR = 8.76;P<0.001).In the “explained” group,7 were RLS level IV,6 were level III,7 were level II,and 14 were level I.For the “unexplained” group,the numbers of patients with levels IV,III,II and I were 27,26,12,and 14.Conclusions:1 、 The incidence rate of PFO and age are independent risk factors for unexplained dizziness.The incidence of PFO is higher in patients with unexplained dizziness,and a large number of right-to-left shunts in PFO are more closely related to dizziness.2、Other influencing factors of dizziness,such as hypertension,diabetes,body mass index(BMI),dyslipidemia,and other indicators,showed no difference.We do not believe that unexplained dizziness is associated with chronic metabolic syndrome.Similarly,no correlation was found between smoking and alcohol consumption among health behavior variables.