One more thought...doctors often confuse the various myotonias. If your mutation was on the gene SCN4A rather than CLCN1 your AVNRT could be caused by the potassium issues related to those mutations. This article mentions electrolyte imbalances:

http://www.heart-consult.com/articles/what-avnrt

I'm assuming you've been checked for hyperthyroidism and told to restrict caffeine.

Also if your neck injury is around the sixth cervical vertebrae, that affects the vagus nerve which controls the heart rate and could be provoking the tachycardia.

Jan

Type of Myotonia: Thomsen's

Country: USA

Jan, thank you so much for your response. You have a wealth of knowledge! I have a recogonized mutation associated with MC on the CLCN1 gene and an unrecognized mutation (that the testing lab thinks is non-significant) on the SCN4A gene. I will email you my results as soon as I can scan it all to send to you.

I do stay away from caffine. Regarding the thyroid, I developed a thyroid infection last year that first caused hyperthyroidism and now hypothyroid. I am currently being treated with Synthroid. It aggravated everything and really elevated my HR even more for awhile. They gave me Metopropol for the elevated HR, which I have since stopped.

Thanks for the references for natural treatments. I prefer them when possible. I will check on the location of the neck injury. It would be very interesting if that was causing and/or aggravating the HR issues.

Off to bed now so i can be functional for work tomorrow...

Linda

Type of Myotonia: Thompson's

Country: US

Hi,
There are currently 102 known defects in the SCN4a gene. About thirty (30) of them present phenotypically distinct disorders. Several of the 72 remaining were created in research labs to present very narrowly defined disorders for ease of testing. Because the bulk of
SCN4a defects are very rare and present with mixed symptoms, or with some mild symptoms
they may be cataloged as benign. Some symptoms consistent with Thomsens may be the result
the Sodium Channel defect instead.

Athena Diagnostics has a computer model that says that my SCN4a defect is benign but my delayed onset, Potassium Aggravated Myotonia has shaped my whole life and left me disabled for the last 12 years.

In response to your previous posts I suggested Dr. Stephen Cannon, he is still your best bet for good and complete treatment.

Type of Myotonia: SCN4a

Country: US

Joe,

I agree that the associations are sometimes incorrect. While we have a confirmed CLCN1 mutation that has caused symptoms of Thomsen's Disease all through my family, I recently had a test which indicated I also have a mutation (S524G) on the SCN4A gene. It is also listed as unknown significance, but I am very sensitive to potassium and one of my daughters has symptoms that are consistent with PAM or paramyotonia congenita. She is in a wheelchair much of the time but my other family members with Thomsen's don't seem to be affected by potassium at all and they don't experience the weakness that bothers us.

Is Dr. Cannon in California now?

Jan

Type of Myotonia: Thomsen's

Country: USA

Dr Cannon is Associate Dean of Medicine at the University of Texas Southwestern in Dallas.

Type of Myotonia: SCN4a

Country: US

Thanks, Joe. I emailed him and he responded right away. He said that the amino acid change is in a region of the gene that could impact the channel function. It hasn't been associated yet as disease-causing in research studies, but it would certainly explain our greater sensitivity to potassium and cold as well as weakness that isn't typically seen as much in MC.

Jan

Type of Myotonia: Thomsen's

Country: USA