Tachycardia Symptoms and Adrenal Fatigue Syndrome – Part 1
Mitral valve prolapse syndrome, chronic orthostatic intolerance, and orthostatic tachycardia symptoms are each names that reference postural tachycardia syndrome (POTS). POTS is not a new illness. It is caused by a malfunction of the patient’s autonomic nervous system (ANS).
Tachycardia Symptoms and Postural Orthostatic Tachycardia Syndrome (POTS) 101
The autonomic nervous system (ANS) governs the involuntary inner workings of our body through five separate but related branches. They control functions such as heart rate, blood pressure, digestion, temperature control, bladder control, sweating, and the fight-or-flight response to stress. The two most famous branches are called the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The ANS branch is regulated by neurotransmitters and hormones like dopamine, norepinephrine, epinephrine (also called adrenaline) and acetylcholine. Any illness caused by dysfunction of the ANS is collectively called dysautonomia.
POTS is a subset of dysautonomia where orthostatic (blood pressure) intolerance is associated with the presence of excessive tachycardia (fast heart rate) on standing. It is believed to be caused by central hypovolemia.
Between 75 and 80 percent of POTS patients are female and of menstruating age. Most male patients develop POTS in their early to mid-teens during a growth spurt or following a viral or bacterial infection. Some women develop POTS or tachycardia symptoms with pregnancy.
Physiology of POTS
When lying down, 25 percent of our blood lies in our chest cavity. Upon standing, 500-1000 cc of blood is pulled from our chest to the abdomen and legs by gravity. To maintain adequate blood profusion to our brain and prevent fainting, the SNS is automatically activated, with norepinephrine released by the brain. This hormone travels to the heart and peripheral blood vessels, narrowing blood vessels and increasing the heart rate. Blood flow to the brain is increased. Without norepinephrine, one simply cannot maintain an upright position for long in day-to-day living. Many of the POTS or tachycardia symptoms come from this inability to move the blood quickly to the brain.
Epinephrine, another hormone, also plays a part in normal daily life, though in a much lesser degree. It is primarily released when the body is under severe stress. As part of the fight-or-flight response, epinephrine is the body’s last response to stress. It acts to supply blood to brain and muscle in order for us to survive. It is under the control of the adrenomedullary hormone system.
SNS activation in normal people causes the normal heart rate to increase transiently by 10-15 beats per minute along with a very slight increase in blood pressure on standing. Instantly, an automatic vessel dilatation occurs and blood pressure and heart rate returns to normal. In some people, these activation and feedback mechanisms fail, altering the first increase in profusion and subsequent normalization of blood to the heart and brain. This is when the POTS and tachycardia symptoms surface. Blood pressure falls (orthostatic intolerance), with a compensatory rise in heart rate (tachycardia) when it is too fast.
Remember that as a syndrome, POTS is a collection of symptoms. The symptoms are widespread throughout the body because of the all-encompassing effect of the ANS internally. No organ system can fully escape. You don’t need to have all the symptoms to be diagnosed. They can include:
- Light-headedness or dizziness upon standing or even with prolonged sitting. Some describe it as a sense of almost fainting. Approximately 30 percent of people with POTS experience syncope.
- Fatigue and lethargy. Overwhelmingly the vast majority of POTS patients experience severe fatigue. This can last for a considerable time after a bout of POTS symptoms.
- Fast heart rate or palpitations. There is also a sense of heart pounding commonly associated with this. In severe cases, tachycardia symptoms such as atrial fibrillation and supraventricular tachycardia can be triggered.
- Anxiety is very common. This can be accompanied by chest pain.
- GI problems, such as nausea, bloating, cramps, vomiting, diarrhea, and constipation. The gut is irritable. Many are told they have irritable bowel syndrome.
- Brain fog. This can happen before or after bouts of POTS, and may reflect blood profusion issues to the brain.
- Shakiness and hypoglycemia. Some have concurrent low blood sugar and related symptoms after a bout of POTS.
- Headaches. Both vascular and migraine type headaches can be experienced. They tend to be better when lying down and worse in an upright position.
- Shortness of breath. Patients can feel breathless when standing or during slight exertion.
- Excessive or reduced sweating can be seen if other branches of the SNS are involved that regulate sweating.
- Visual problems. These can be described as excessive glare, blurred or tunnel vision.
Diagnosis of POTS
If your doctor suspects POTS, a tilt table test is ordered. You lay down on a table, which is then tilted while cardiovascular biomarkers are measured. In adults, POTS is clinically diagnosed when there is a heart rate increase of 30 beats per minute (bpm) or more from baseline, or over 120 bpm within the first 10 minutes of standing in an upright position. Unfortunately, many times the results can be inconclusive or borderline.
While the diagnostic criteria of POTS focuses on the abnormal heart rate increase upon standing, sufferers usually present with a wide set of symptoms beyond blood pressure and rate irregularities. Some POTS patients have no blood pressure dysregulation on standing. Many have high levels of plasma norepinephrine while standing, reflecting increased SNS tone. Norepinephrine acts on the brain and triggers anxiety.
Remember that a person with POTS is stressed every time she/he moves or stands. There is a constant over-release of epinephrine and norepinephrine. It is for this reason that POTS is so often misdiagnosed as anxiety.
The key to proper diagnosis of POTS should factor in the many possible associated symptoms to form a complete clinical picture of an overall autonomic nervous system in disarray.
As with any syndrome, the continuum of dysfunction varies from mild to severe. Those with mild symptoms lead normal lives. In severe cases, even mundane daily activities such as eating, walking, and bathing can be problematic.
Approximately 25 percent of POTS patients are disabled and unable to work.
Illnesses frequently associated with POTS include fibromyalgia, viral illness, autoimmune disease, adrenal disorders, mast cell disorders, hypersensitivity of baroreceptors, chronic fatigue syndrome, post traumatic stress disorder, panic attacks, inappropriate sinus tachycardia, irritable bowl syndrome, type 1 diabetes, Lyme disease, and mitochondrial diseases. This is clearly a complicated and convoluted disorder because of the widespread effect of the ANS in the body.
Different Types of POTS
To better describe the pathophysicology of POTS, it can be grouped in various ways, such as primary (unknown cause) and secondary (caused by something else) POTS, hypovolemic POTS (associated with low blood volume), partial dysautonomic POTS (associated with a partial autonomic neuropathy), and hyperadrenergic POTS (associated with high levels of norepinephrine).
About 20-30 percent of POTS patients fall into this group. It is characterized by a high normal level of plasma norepinephrine in the supine position, while the upright norepinephrine is usually elevated (>600 pg/ml). As the name implies, it is caused by an uptight sympathetic nervous system. In some subjects, this hyperadrenergic response may be a compensatory reaction to either hypovolemia or peripheral dysautonomia with venous pooling.
Hyperadrenergic POTS has a strong familial link, and is associated with light sensitivity, stress intolerance, adrenergic urtricia, and medication sensitivities.
There is a strong link between hyperadrenergic POTS and Adrenal Fatigue Syndrome (AFS).
Conventional Treatment of POTS
Treatment of POTS should be directed at the underlying cause as the top priority and long-term solution. Unfortunately, root causes usually evade detection without a very detailed history. Most physicians trained in Western medicine tend to focus on symptoms control as follows:
Increase fluid intake to support volume and adrenal function
Use of firm compression support socks (compared to mild compression socks, for varicose veins) can avoid blood pooling in lower extremities.
Avoidance of diuretics such as coffee, tea and medications with that effect.
Focus on reclining exercises such as rowing instead of upright exercise such as running.
Prescribe medications such as Fludrocortisone, Adderall, Pyridostigmine, Benzodiazepines, Beta Blockers, ProAmitine (Midodrine), and Clonidine, SSRIs such as Prozac or Zoloft, and Dexedrine. In severe cases, Florinef may be considered. Beta blockers and calcium channel blockers can be used to reduce high resting heart rate.
© Copyright 2014 Michael Lam, M.D. All Rights Reserved.
Dr. Lam’s Key Question
I feel very good doing yoga exercises, but some poses, where my head is below my heart, can give me some dizziness, is that normal?
That can happen to some people, especially those with circulation issues. If that happens, skip those poses. Also, find out from your doctor why you have dizziness during those poses.