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Avatar universal

Unresolved/unexplained tachycardia is still a mystery?

  I have a strange situation that has been unresolved by GPs, cardiac specialists,
  neurologists, and pathologists for almost ten years.
  When I was about 15, I passed out on the football field during after-
  school band practice.  Every day, while standing completely still,
  I continued to pass out.  The heat was not too bad, though everyone was
  sweating.  My parents passed it off to heat exhaustion and took me out
  for a few weeks.  When I went back, it came back, and I continued to pass
  out after standing still for a few minutes.
  Finally, they took me to the hospital for some tests to see what the
  problem was.  They ran the following tests on me over the next few
  weeks, and all were declared normal:
  24-hr EEG
  Sleep Deprived EEG
  CAT Scan
  Regular Glucose Test
  Fasting Glucose Test
  Two years later, I became pregnant.  I noticed during the entire term
  of the pregnancy that my heart rate would become elevated for long periods
  of time, causing me to become dizzy and sometimes pass out.  At this point
  my OBGYN ran another glucose test, which was normal.  He said I was anemic
  but it wasn't related to my problem.  He referred me to a cardiologist,
  who then ran an EKG and an ECG, as well as a 24-hour holter monitor. When
  the results came back, he said there was definitely an increased rate of
  heartbeat but that it wasn't my heart that was the problem.  Again, I
  was back at square one.  
  A few years later, I went back to my GP for another opinion.  He took my
  blood pressure, which was the same while laying down, sitting up,
  and standing up, though the heart rate was markedly increased while standing
  up.  He couldn't explain the probem, prescribed beta-blockers, and they
  seemed to help.  However, when I went back for a re-eval a year later to
  get another prescription, the condition was gone, and he couldn't
  re-prescribe it again.
  Here are the symptoms:
  When I'm standing still for more than a few moments (ex. standing in a check-out
  line) my heart rate increases to anywhere from 120 to 180 and stays there until
  I either pass out or sit down.  When I'm sitting down, it can run anywhere
  from 100-140, and when laying down is around normal (70-90).  My blood
  pressure remains the same no matter what position I'm in.  This condition
  appears sporadically; it's not a constant every-day thing.  It comes and
  goes seemingly at random; the majority of the time I am under stress but
  not always.  It comes in periods of a few months and then goes away again.
  Beta blockers seem to help. (I was on Lopressor 50 mg twice a day to control
  It seems to be aggravated by heat but is not dependent on heat to occur. It
  occurs when I'm fully rested or completely exhausted.  It doesn't appear
  to occur any more intensely after eating.  Caffeine and nicotine intensify
  the effect but stopping the intake of them have not stopped the problem.
  I've looked for resources for an explanation but have come up drastically
  short.  Every doctor has been baffled and no one seems to know why I have
  this problem.  Since it's sporadic, I never know if it's going to be happening
  when it's time for a new prescription.  Help!!
1 Responses
Avatar universal

Dear Janet,
The problem you describe is somewhat unusual, which I suspect has led to the conflicting opinions you've received, and the general difficulty in treating this condition.  Your symptoms fall under the category of syncope (or loss of consciousness), even though you don't always lose consciousness-- having learned to abort these episodes by sitting or laying down.  Syncope has many causes, many of which are benign, but some of which herald more serious underlying problems.  In your case, you mention tachycardia in the absence of hypotension.  I'm a little doubtful that you're passing out in this circumstance, unless the high heart rate is enough, of itself, to compromise the flow of blood to vital organs such as the brain.  Tachycardia rarely does this unless there are structural abnormalities of the heart, such as hypertrophic cardiomyopathy, critical aortic valve stenosis, and multiple other problems that are often diagnosed by echocardiography (an ultrasound test used to image the heart).    I suspect that when you are about to pass out, your blood pressure is indeed low, despite the fact that this has not been documented.  It would be useful to first perform a tilt-table test to see whether you have an element of orthostatic hypotension (blood pressure falling with standing with increasing heart rate).  Also,  the syndromes of "postural hypotension" need to be considered.  There are several varieties of these conditions, some associated with high adrenergic (adrenaline) states, and others with low adrenergic states.   Depending on the condition, there are various treatments available... therapies which would likely improve your symptoms.  
I can sympathize with your frustration.  However, it sounds as though you have clearly exceeded the routine medical resources, and now need more specialized consultation and evaluation.  I recommend that you arrange to be evaluated by an expert in syncope or postural hypotension,  preferably by an individual who can reevaluate the tachycardia component of this problem to determine whether the high heart rate is a normal response to falling blood pressure, or whether it is itself causing the loss of consciousness.  Dr. Jaeger or Dr. Fouad at the Cleveland Clinic would be able to perform a thorough and detailed evaluation of your condition.   An appointment can be made by calling 1 800 CCF CARE.   If a trip to Cleveland is not practical, I suggest that you visit the largest university medical center/teaching hospital in your area and seek consultation at that institution.  Best of luck with your condition.  I hope you get some answers.
Information provided in the Heart Forum is for general purposes only.  Specific diagnoses and therapies should only be made by your personal physicians.  

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