Electrocardiographic and Hemodynamic Changes During Tilt-Table Testing in Patients With Syncope

Background Syncope is a common clinical condition with diverse underlying mechanisms, making its evaluation challenging. Tilt-table testing is widely used to assess autonomic and cardiovascular responses; however, the role of electrocardiographic (ECG) parameters in differentiating syncope types remains unclear. Methodology This retrospective study analyzed patients who underwent tilt-table testing for syncope evaluation in 2023-2024. A total of 59 patients were included and divided into three groups: orthostatic hypotension (n = 20), vasovagal syncope (n = 19), and negative test results (n = 20). ECG parameters (P-wave duration, PR interval, QRS duration, QTc interval, and T-wave duration) and hemodynamic variables (systolic and diastolic blood pressure and heart rate) were assessed at five time points. Linear mixed models were used to evaluate the effects of group, time, and their interaction. Results Most ECG parameters showed significant changes over time; however, no consistent group-time interactions were observed, indicating similar temporal patterns across groups. P-wave duration and PR interval differed between groups. In contrast, both systolic and diastolic blood pressure demonstrated significant group-time interactions (p < 0.001), reflecting distinct hemodynamic response patterns between syncope types. Heart rate increased significantly during orthostatic testing but did not differ between groups. Conclusions ECG parameters reflect general autonomic adaptation but lack specificity for differentiating syncope etiology. In contrast, hemodynamic responses, particularly blood pressure changes, provide greater diagnostic value and should be the primary focus during orthostatic testing.