Postural orthostatic tachycardia syndrome and orthostatic intolerance in adult patients with active cancer.

BACKGROUND: Postural Orthostatic Tachycardia Syndrome (POTS) is a variant of autonomic dysfunction (AD) defined by an increase in heart rate (HR) ≥ 30 bpm within 10 minutes (min) of a change from the supine to an upright position, in the absence of orthostatic hypotension. Many studies suggest that AD is common in active cancer patients and is associated with variable symptoms and decreased survival. Based on this evidence, we hypothesized that POTS can be associated with active cancer and might contribute to some of these patients' symptoms and survival. METHODS: Consecutive 220 active cancer patients aged 19-59 were enrolled. They were asked to lay flat for 5-10 min then to stand for 10 min without support. Total of 5 blood pressure (BP) and HR readings were taken (immediately before standing up then immediately after, and at 3, 6, and 10 min while standing). All patient's symptoms were recorded. RESULTS: 213 patients were included. Age was 48 ± 8, 76% were females,18% had metastasis and 43% were on chemotherapy. 55% reported symptoms of AD, with symptoms associated with standing were reported in 28%. Baseline HR was 76 ± 13 bpm, and systolic BP was 129 ± 20. Upon standing, HR increased by 10 ± 3 bpm and systolic BP dropped by 1.3 ± 0.4. Immediately after standing, 47 (22%) Patients developed symptoms.18 patients (8.5%) met the criteria for POTS, where HR increased by 37 ± 5 with an increase in systolic BP by -1.6 ± 6. Patients with POTS had higher HR upon standing (p = 0.000), HR at 3 min (p = 0.005), HR at 6 min (p = 0.002), and HR at 10 min (p = 0.000). In contrast, baseline HR and BP showed no significant difference between patients with and without POTS (p = 0.74 and 0.11). After 16.9 ± 5.5 months, there was no statistical deterrence in all-cause mortality between POTS and non-POTS patients. CONCLUSION: POTS and orthostatic intolerance are prevalent in active cancer, where onset of symptoms started after cancer diagnosis in many patients. These patients have a significant association with higher HR upon standing and overall prognosis comparable to that of patients without POTS.