Electroacupuncture and vagal AF
XI'AN, SHAANXI, CHINA. Orthostatic intolerance (OI) affects an estimated 500,000 Americans and manifests itself through a wide range of symptoms including headaches, nausea, diminished concentration, and even fainting. It is particularly likely to occur when changing position from supine (lying down) to upright. It is believed that the condition is caused by inadequate blood flow to the brain, at least partially mediated by a weak sympathetic response from the autonomic nervous system (ANS).

The presence and severity of OI is evaluated in the laboratory through the means of a head-up tilt (HUT) test, or the application of lower body negative pressure (LBNP). In the HUT test the patient starts out lying flat on their back on a tilt table. The table is then tilted towards the upright position and the patient's vital signs (heart rate, blood pressure, heart rate variability, etc) are measured whilst watching out for signs of fainting. The LBNP test is more complex. It involves placing the lower part of a patient's body in an airtight chamber and then creating a partial vacuum resulting in a transfer of blood from the upper part of the body, including the brain, to the lower part.

A group of researchers from the Fourth Military Medical University in China now reports that OI can be significantly relieved by the application of electroacupuncture (EA) to the Nei Guan (PC6) acupuncture points.

Nei Guan (PC6) is located on the pericardium meridian about two and a half fingers width above the crease of the wrist on the inner arm between the two tendons. The pericardium meridian controls blood flow as well as pulse rate. Stimulation of the Nei Guan point has been used to counteract palpitations and a sense of fullness in the chest. There is also evidence that it helps restore ANS balance. Nei Guan is also the number one point for treating nausea, seasickness, and morning sickness.

Their clinical trial involved 30 healthy young individuals (21 men and 9 women with an average age of 23 years) who were assigned to receive EA at Nei Guan points, EA at sham acupuncture points on the shoulders, or no EA treatment (controls). Twenty of the participants had their EA administered for 30 minutes prior to HUT/LBNP testing (group A), whilst 10 had EA treatment during HUT/LBPN testing (group B). All participants served as controls, or were given real or sham acupuncture on three separate days in random order.

There was a significant increase (about 15%) in the time elapsed from the start of the HUT/LBPN testing to the development of signs of presyncope (precursor to fainting) amongst those in both groups A and B who had received EA at the Nei Guan points. Diastolic blood pressure was also significantly higher amongst Nei Guan EA recipients than amongst controls and those who received sham acupuncture (76 vs 69 mm Hg). Nei Guan EA decreased the high frequency (vagal) ranges of heart rate variability, whilst increasing the low frequency (adrenergic) ranges whilst in the supine position. Finally, Nei Guan EA resulted in an increase in the concentrations of epinephrine (adrenalin) and norepinephrine (noradrenalin), thus indicating increased sympathetic (adrenergic) activity of the ANS.

The researchers conclude that EA at the Nei Guan points improves orthostatic tolerance via up-regulation of both the cardiac and peripheral sympathetic nervous system.
Sun, J, et al. Electroacupuncture improves orthostatic tolerance in healthy individuals via improving cardiac function and activating the sympathetic system. Europace, Vol. 15, 2013, pp. 127-34

Editor's comment: The finding that acupuncture at the Nei Guan points (PC6) increases sympathetic activity in the supine position could be of great interest to vagal afibbers who often experience excessive parasympathetic (vagal) dominance when lying down or resting, triggering an AF episode. Although electroacupuncture is obviously not accessible to everyone, it is possible that wearing a bracelet designed to combat nausea and seasickness when resting may be beneficial for vagal afibbers. Such bracelets are available in pharmacies and health food stores, and are specifically designed to put pressure on the Nei Guan point.