ID 5 – Head-up tilt table test in differentiating neuropathic from hyperadrenergic type of postural orthostatic tachycardia syndrome (POTS)

Abstract

to investigate differences between hyperadrenergic and neuropathic type of POTS in cardiovascular response to orthostatic provocation. Forty-three POTS patients underwent head-up tilt table test (HUTT) protocol: 10-minute supine phase and 30-minute 70° tilted phase. Serum catecholamine levels were determined and patients were categorized into one of two types of POTS. Ten patients had hyperadrenergic (group 1) and 33 had neuropathic (group 2) type of POTS. In group 1, 80% of the patients were men, and in group 2, 69.7% were women (p = 0.005). Group 1 had higer values of heart rate during supine phase (82.6 ± 16.3 bpm vs. 73.8 ± 10.4 bpm, p = 0.048). Group 2 had earlier tilted phase mean ending time (8.8 ± 6.8 min vs. 21.2 ± 4.5 min, p = 0.001) as well as lower values of diastolic blood pressure difference between 1st minute of tilted phase and supine values (−1.7 ± 7 mmHg vs. 5.6 ± 7.5 mmHg, p = 0.007). Using observed differences in response to orthostatic provocation we developed a HUTT model for differentiating neuropathic POTS with sensitivity of 76% and specificity of 80%. Prolonged HUTT can differentiate between two types of POTS. This study provides evidence that prolonged HUTT is valuable in making diagnostic and treatment decisions in POTS.