What happened?

Annika's story is incomplete without sharing one final piece: what the heck happened?  After all, it's not normal for seemingly healthy children to collapse on the church steps.

While we don't have all the answers, we know quite a bit.  An analysis of Annika's entire genome revealed a variation (mutation) of her TNNT2 gene, which is causing some health challenges.  (Neither Jason nor I carry the gene variation, so it's unlikely that any one else in the family is affected.)  TNNT2 codes for Cardiac Troponin T, which is one of three proteins that make up the troponin complex, found exclusively in cardiac muscle.  Troponin is really important for cardiac muscle contraction.  Thus, it makes sense that if this gene isn't coding as expected, your heart will not contract as expected either.

For Annika, the genetic change in her TNNT2 has caused a couple of health conditions.  First of all, she has hypertrophic cardiomyopathy or HCM.  This means that some of the heart muscle along the inner septum of her left ventricle has become thickened and fibrous.  This can cause problems in a couple of ways.  First of all, stiff scar tissue doesn't expand and contract the way healthy cardiac muscle should.  Secondly, the hypertrophy or thickening lessens the amount of space available for blood to fill the ventricle.  

On the outside wall of her left ventricle, Annika also has left ventricular noncompaction, meaning that the heart muscle never developed properly.  It stayed spongy with deep crypts instead of transforming into smooth firm muscle.  This tissue likewise struggles to fully contract or relax--both of which are important for proper heart function.

When I first learned about cardiac muscle in my anatomy class, I was extremely impressed by how well-organized it is.  Check out this slide of cardiac tissue, courtesy of a histology class at SIU.

Well, some of Annika's cardiac tissue is far less organized, meaning that the electrical signals traveling between cells can get garbled.  We suspect that at the moment of Annika's collapse, the scrambled electrical signals must have hit just the wrong frequency, thereby causing a life-threatening arrhythmia--ventricular fibrillation.

All of this is pretty scary.  In reading about both hypertrophic cardiomyopathy and left ventricular noncompaction, there is the risk that for a very small portion of the population, the first symptom is cardiac arrest and sudden death.  These are the horror stories you hear about the high school athletes who collapse on the field with no warning.

Well, Annika's story was a near miss, barely averting a similar tragedy.  Now, however, we are in a much better place.  Because we know what is going on, we are able to treat her heart and keep these conditions from progressing.   She is taking a beta-blocker to help with heart rate and arrhythmias, an ace-inhibitor to control blood pressure, a couple of diuretics to limit the amount of fluid her heart needs to pump, and a blood thinner to help break up any clots.  Her pill box looks like it belongs to a geriatric, but we hope it will keep her safe.

This week for my pharmacology class I listened to an online lecture entitled Heart Failure where they specifically referenced four out of five of Annika's meds.  The term "heart failure" is hard for me.  Yes, I suppose we need to accept the fact that Annika's heart did indeed malfunction and we are now treating this failure.  Still, I much prefer to look at her medication regime as setting her up for "heart success."  Plus, we now have her ICD (Internal Cardio Defibrillator) as a life-saving backup should things ever go awry. 

Knowing Annika, I suspect that she will continue to heal from her cardiac arrest and shock the doctors with her health.  Her feisty spunk is not to be underestimated!  While the TNNT2 gene for cardiac troponin is known, Annika's specific variation is not found anywhere else in the medical literature.  One of her cardiologists explained how she was reaching out to doctors all over because Annika's case is so unique.  She said that most heart doctors would only see a case or two like it in their entire lifetime.  Our Annie Mae really is one in a million!

If you were to visit with Annika this afternoon, you would be surprised by how healthy she seems.  Were it not for her scars, you'd never know she'd been sick!  Skiing and swallowing liquids excepted, she's back to living her best life.  And a beautiful life it is!