Abstract 054: Altered Valsalva Maneuver Hemodynamics In Postural Tachycardia Syndrome

Abstract

Postural Tachycardia Syndrome (POTS) is often associated to subtle cardiovascular autonomic alterations. Valsalva maneuver (VM) is commonly used in clinical settings to assess autonomic functions. Specific hemodynamic responses during VM phases can support POTS diagnosis and can provide pathophysiological characterization.We hypothesize that POTS patients present differences in VM morphology with respect to healthy controls. We conducted a case-control study enrolling subjects with prior clinical diagnosis of POTS and controls. ECG and finger blood pressure were continuously recorded during an against-resistance expiratory effort, producing a 30-mmHg straining pressure for 15 seconds in supine. Hemodynamic parameters were computed in absolute terms at baseline, early (VM2e) and late (VM2l) phase 2, phase 3 (VM3) and phase 4 (VM4) and in inter-phase changes. We studied 13 POTS and 12 controls matched for age (28 ±2 vs 31 ±3 ; p=0.98) and BMI (24.2 ± 1.0 vs 23.2 ± 0.8; p=0.46). Mean HR was increased at baseline (80 ±4 vs 69 ±3 bpm; p<0.05). POTS had higher absolute SBP during VM3 (90 ±4 vs 76 ±4 mmHg; p<0.05) and VM4 (124 ±5 vs 112 ±3 mmHg; p<0.05). Figure shows higher HR increment (22 ± 2 vs 12 ±4 bpm; p<0.05) during VM2e and greater SBP rise (17 ± 4 vs 10 ±3 mmHg; p<0.05) in VM2l compared to controls. VM4 SBP overshoot increase was similar (17 ± 3 vs 14 ± 3 mmHg; p=0.36). POTS have higher SBP rise during VM2l and higher VM2e HR increase. These results suggest that VM analysis can aid clinical diagnosis and that maximal baroreceptor unloading creates higher tachycardic response and vasoconstriction in POTS.