OBJECTIVES:To evaluate the relationship between weight loss velocity following bariatric surgery and the onset and long-term persistence of Patulous Eustachian Tube (PET) symptoms. METHODS:Sixty patients who underwent laparoscopic sleeve gastrectomy were prospectively evaluated. Otological assessments and the Eustachian Tube Dysfunction Questionnaire (ETDQ-7) were completed preoperatively and postoperatively at 1, 3, 6, and 12 months. Patients were categorized into Asymptomatic (Group 1), Recovered (Group 2), and Persistent (Group 3) groups based on 12-month clinical trajectories. Postoperative weight loss velocity was calculated via periodic BMI (Body Mass Index) change rates (ΔBMI%). RESULTS:The overall PET symptom onset rate was 55.0% (n = 33), with 43.3% (n = 26) experiencing spontaneous resolution and 11.7% (n = 7) developing chronic symptoms. No significant difference was found in 12-month excess weight loss percentage (%EWL) success rates among groups (p = 0.577). However, BMI decline velocities demonstrated highly significant intergroup variances (p < 0.001). ROC analysis revealed that an initial 0-3 month BMI decline exceeding 25.0% significantly predicted symptom onset (p = 0.003). Remarkably, a 3-6 month BMI decline velocity above 22.4% predicted long-term symptom chronicity. (p < 0.001), yielding a sensitivity and negative predictive value of 100%. Higher preoperative BMI was significantly associated with symptom persistence. CONCLUSION:The onset and long-term persistence of post-bariatric PET symptoms are fundamentally dictated by postoperative weight loss velocity rather than absolute weight loss. A sustained high-velocity BMI decline between Months 3 and 6 serves as the definitive clinical predictor for chronicity, demanding close monitoring. LEVEL OF EVIDENCE: 3: