Key result
During head-up tilt testing in a patient with POTS, heart rate increased by 30 beats/min within 5 minutes and the LF/HF ratio increased in parallel with the onset of orthostatic intolerance.
Case Report (n=1)
No
In a patient with POTS, an increased LF/HF ratio during head-up tilt testing correlated with the onset of orthostatic intolerance, suggesting sympathetic hyperactivity.
Should not change POTS evaluation; hypothesis-generating for sympathetic hyperactivity during tilt testing.
A 16-year-old boy was diagnosed with idiopathic postural orthostatic tachycardia syndrome (POTS) during head-up tilt testing. During a passive tilt, the patient's heart rate (HR) increased by 30 beats/min within 5 min. After 25 min of tilting, his HR further increased to 133 beats/min and he began to complain of lightheadedness and weakness without hypotension. Power spectral analysis of HR variability during the tilt test revealed that the ratio of low and high frequency powers increased with the onset of orthostatic intolerance. Propranolol (10mg every morning) dramatically alleviated his clinical symptoms, and he has been asymptomatic with gaining weight after discontinuing his crowded train commuting.
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Sumiyoshi et al. (1999) conducted a case report in Idiopathic postural orthostatic tachycardia syndrome (POTS) (n=1). Head-up tilt testing vs. Supine position (baseline) was evaluated on Heart rate and heart rate variability (LF/HF ratio). During head-up tilt testing in a patient with POTS, heart rate increased by 30 beats/min within 5 minutes and the LF/HF ratio increased in parallel with the onset of orthostatic intolerance.
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