Posted 11/18/2010 3:55 AM (GMT 0)
POTS (Postural Tachycardia Syndrome)
POTS (Postural Tachycardia Syndrome) is a condition where you have a rapid heart rate but low blood volume and low blood pressure which can result in the pooling of fluids in lower extremities (i.e. ankle swelling) . The syndrome has a history in medicine, known by many other names such as: Soldiers Heart, Effort Syndrome, Irritable Heart, Neurocirculatory Asthenia, Orthostatic Intolerance, Idiopathic Hypovolemia, Mitral Valve Prolapse Syndrome and Orthostatic Dysregulation. POTS is generally characterized by fluids (largely lymph) moving from the blood vessels to the interstitial space causing a decreased venous return to the heart and decreased arterial pressure. POTS can appear as any or all of the following symptoms:
1) Sympathetic nervous system activation (neurally mediated hypotension)
2) Pooling of fluid in the lower extremities (swelling)
3) Elevated heart rate often accompanied by low blood pressure
4) Extreme fatigue
5) Headache
6) Back pain
7) Poor quality of sleep
8) Abnormal sweating of the lower extremities (legs)
9) Brain Fog
10) Increased levels of the neurotransmitter Norepinephrine
11) Low blood volume (hypovolemia)
12) Autonomic imbalance (poor balance)
13) Blurred vision
14) Shortness of breath
15) Tunnel vision
16) Anxiety
17) Decreased ability to focus and poor attention skills
18) Feeling worse when standing upright
19) Lower extremities have a "blue" color and are cold to touch
20) More prevalent in women of childbearing age
21) Symptoms are worse during the premenstrual phase
22) Decreased blood flow to the skin
23) Neurally mediated syncope (fainting)
The pathophysiology of POTS is not entirely understood at this time however, Dr. Satish Raj at Vanderbilt University, is currently researching the physiological mechanisms that give rise to such a condition. Interestingly, it appears that there may be damaged sympathetic nervous system innervation of the blood vessels that service the extremities (arms, fingers, legs, toes) which leads to fluid retention (swelling). Pooling of this fluid results, causing the heart to essentially pump faster due to low blood volume as a compensatory mechanism.
Neurohormonal regulation of low blood volume is regulated largely by the renin, angiotensin II, aldosterone system, where the kidney plays a key modulatory role in the release of renin. This is important in POTS because the kidney is responsible for filtering fluids and retaining sodium, which contributes to the maintenance of proper osmolality in the blood. Ultimately there may be problems with sodium retention and consequences with maintenance of blood volume.
Mast cell activation often occurs with POTS as well. Mast cells are responsible for the release of histamine (i.e., generally associated with allergic reactions). Symptoms of mast cell activation with POTS can include:
1) Increased urination
2) Lightheadedness
3) Shortness of breath
4) Gastrointestinal symptoms (i.e., diarrhea, nausea, vommiting)
5) Increased urine methylhistamine, the primary metabolite of histamine
6) Episodic flushing
7) Sensation of warmth in certain areas of the body
This increased release of histamine via mast cell activation may be treated with antihistamines and aspirin, however, your physician should advise you on your treatment of this.
There are various treatments for POTS depending on the etiology of symptoms, but the following are general recommendations that may be helpful to you:
1) Drink 6-8 16oz glasses of water or green tea per day
2) Maintain adequate sodium in your diet
3) Use elastic support hose to minimize fluid retention in the legs (you can purchase these at a high quality pharmacy)
4) Exercise daily - walk 20-40 minutes daily briskly, also use light weight exercise 3 times a week
5) Use physical therapy for deconditioning of muscles from chronic fatigue
6) VIGOROROUS EXERCISE WILL MAKE SYMPTOMS WORSE
A variety of treatments for POTS is available and you may want to consider discussing these issues wi