Abnormal gastric myoelectrical activity in postural tachycardia syndrome
- Source: Clinical Autonomic Research, Dec 2, 2012
By William H Seligman, et al.
[Note: To read the first 2 pages of this article, click ‘Look Inside’ here. Many people with ME/CFS and fibromyalgia experience symptoms of autonomic dysfunction, and often are diagnosed with the form called POTS. The muscles of a well functioning GI tract produce paced, rhythmic contractions (peristalsis) to propel food smoothly down to the stomach, mix it up, empty the stomach, and propel the contents through the large & small intestines. The measures reported in this study of POTS patients identified disruptions in this process.]
Objective: Postural tachycardia syndrome (PoTS) is an important cause of orthostatic intolerance resulting from cardiovascular autonomic dysfunction. In addition to postural symptoms, PoTS patients may have allied features, including gastrointestinal (GI) symptoms, which have not yet been thoroughly investigated.
We evaluated gastric myoelectrical activity in PoTS patients.
Methods: Using cutaneous electrogastrography (EGG), we recorded gastric myoelectrical activity before and after standard liquid meal ingestion in 15 PoTS patients (age 27 +/- 4 years); including 7 with and 8 without GI symptoms, and in 11 healthy individuals (age 23 +/- 7 years). We performed spectral analysis of EGG recordings to obtain the dominant frequency of gastric pacemaker rhythm (DF), instability coefficient of DF (ICDF), and low (LFR%), normal (NFR%), and high (HFR%) range power percentages of the total power.
• Instability coefficient of DF, an index of variability of gastric pacemaker rhythm, was significantly elevated both pre- and post-prandially (30-45 min after the meal) in the PoTS group [overall] (8.8 +/- 6, 10.0 +/- 8%) compared with controls (4.0 +/- 3, 4.0 +/- 3%; both p < 0.05).
• Patients with GI symptoms had significantly higher post-prandial ICDF (15.0 +/- 5%) than those without GI symptoms (5.6 +/- 4%; p < 0.05).
• There were no significant differences in DF, LFR%, NFR% and HFR% before and after the meal between the PoTS and control groups, or between PoTS patients with and without GI symptoms.
Interpretation: Our study revealed increased variability of gastric pacemaker rhythm in PoTS, and these findings might be related to pathophysiology of functional GI symptoms in PoTS.
Source: Clinical Autonomic Research, Dec 2, 2012. Seligman WH, Low DA, Asahina M, Mathias CJ. Department of Medicine, Autonomic and Neurovascular Medicine Unit, Imperial College London, St. Mary's Hospital, London, UK. [Email: firstname.lastname@example.org]