(P147) THE EVOLUTION OF TILT-TABLE TESTING IN TORONTO, ONTARIO: A 10 YEAR, 1000+ PATIENT RETROSPECTIVE STUDY.

Background: Tilt-table test (TTT) is a non-invasive test which may differentiate sub-types of cardiac syncope and assist in the evaluation of non-cardiac causes of altered level of consciousness. Data on the use of TTT is limited, with no data available on the changing use of TTT over time. The latter is important given reports of autonomic dysfunction in a significant proportion of individuals who contracted the COVID-19 infection. In this retrospective study we describe the referral patterns for TTT over a 10-year period in Toronto, Ontario with particular attention to changes in TTT pre- and post- the onset of the COVID-19 pandemic.

METHODS AND RESULTS: Sunnybrook Health Sciences Center is a regional cardiac center located in Toronto, Ontario, and the only center performing TTT in Toronto, Ontario. All patients referred for, and completing a TTT between January 1st 2014 and April 31st 2024 were included. Patient demographics (age, sex), referring provider (Cardiologist vs. Non-Cardiologist), and referring diagnosis (Syncope/Altered level of consciousness vs postural orthostatic tachycardia syndrome (POTS)) were determined. The time prior to March 15th 2020 was considered pre- pandemic. Student’s t-test and Chi-squared tests were used to assess differences in continuous and categorical variables. A p-value of < 0.05 was considered significant.

A total of 1063 patients underwent TTT during the study period: 560 TTT pre- and 503 post-pandemic. Cardiologists were the dominant referring providers for TTT during the study period (86%) with increasing referrals for TTT being made by non-cardiologists post-pandemic (10% vs. 17%; p=0.004). Compared to pre-pandemic, there was an increasing frequency of younger individuals (48.8± 20.3 vs. 42.2 ± 18.4; p< 0.01) and females (58% vs. 73%; p=0.001) referred for a TTT. Tilt-table tests to evaluate for POTS increased post-pandemic (11% vs. 29%; p=0.001). The rate of a positive TTT for syncope (48% vs 34%; p=0.001) and POTS (58% vs 39%; p=0.013) decreased post-pandemic.

Conclusion: A change in referral patters for TTT was noted after the onset of the COVID-19 pandemic. Furthermore, the rate of a positive TTT for both syncope and POTS decreased post-pandemic. Further work to understand this association as well as the appropriateness for TTT with the changing referral indication is suggested.