Hemodynamic Behaviour During Tilt Test in Patients with Long COVID

Ana Leticia Gomes dos Santos1, Christian Goncalves Sassaki1, stella tassinari maximo2, Beatriz Oliveira Machado3, Kelly Correa Baioco Da Silva4, Samuel Minucci Camargo1, Rodrigo O. Marañón5, Jose L Puglisi6, Daniel Gustavo Goroso1
1University of Mogi das Cruzes, 2UniversetyofMogidasCruzesandCollegeSãoLeopoldoMandic, 3Universidade de Mogi das Cruzes, 4Universidade Mogi das Cruzes, 5Faculty of Medicine, Universidad Nacional de Tucumán, CONICET, 6California North State University


Abstract

Postural Orthostatic Tachycardia Syndrome (POTS) is increasingly identi-fied as a long-term sequela of COVID-19 and is characterized by autonomic dysfunction and abnormal hemodynamic responses during postural changes. This study investigates systolic and diastolic blood pressure variability in patients with a history of COVID-19 and symptoms suggestive of POTS using a standardized tilt test protocol. A total of 56 volunteers (37 study group; 19 control) aged 18–75 years were evaluated. The tilt test protocol involved 15 minutes in supine position, 15 minutes in upright position (or-thostasis), and 20 minutes back in supine. Blood pressure was measured every minute using an automatic monitor. Heart rate and posture were con-currently recorded using smartwatches. Statistical analysis included Mann-Whitney tests and time-domain variability indices calculated using PysBio. The mean SBP-DBP difference was 41.4 ± 12.4 mmHg in the study group and 43.8 ± 10.1 mmHg in the control group. During the orthostatic phase, the SBP-DBP difference decreased similarly (35.5 ± 14.0 vs. 35.7 ± 8.5 mmHg), but variability was lower in the study group: SD = 6.76 ± 2.2 vs. 7.49 ± 2.7. Although not statistically significant, these results suggest reduced autonomic adaptation in the post-COVID-19 group. Comorbidities such as hypertension (19.6%) and obesity (14.3%) were more frequent in the post-COVID group. These preliminary findings support the hypothesis that POTS after COVID-19 is associated with subtle impairments in baroreflex-mediated cardiovas-cular control. Further investigations with multivariate analyses and increased sample size are ongoing.