Differences

Even with no knowledge of heart conditions, it’s easy to see Alexander’s heart is significantly different from a normal one.  It was created uniquely, just inside his tiny body and no where else.  However, it has and continues to work for him.  He’s a special heterotaxy-RAI guy that’s fortunate enough to have two ventricles.  The following is how I perceive his differences.  Please remember, I’m just a mom devouring medical documents, not a trained medical professional.

Dextrocardia (Incomplete)

Dextrocardia is when the heart is on the opposite side of the body.  Normally the human heart is located just on the left side of the body with the apex the furthest point left.  Oddly enough, the apex is not at the top of the heart, but the very bottom.  In complete dextrocardia, the heart is just on the right side, with the apex furthest right.  It would look something like this:

Alexander’s dextrocardia is incomplete.  His heart is completely midline, straight as you are looking at him, with the apex of his heart near the tip of his sternum.  

While in itself, this is not a problem, it has many effects.  It makes surgery more difficult, as the parts and structures surgeons are familiar with are not where they normally are, and creates new problems when trying to re-route heart plumbing.  It makes it more difficult to get accurate readings with ECG (electrocardiogram), it makes Echos (echocardiograms/ultrasound of the heart) harder to read.  Most of all, it’s indicative of other structural differences of the heart.

dextro-Transposition of the Great Arteries (d-TGA)

d-TGA generally happens when the heart is forming, near the 24^th day of pregnancy.  Instead of twisting one last time, the Aorta and Pulmonary Artery remain parallel to one another.  While mother is carrying the baby, it has no effect, as the mother oxygenates the blood (baby doesn’t breathe) and the Aorta and Pulmonary Artery are connected by the Ductus Arteriosis (DA).  For such a simple problem, it devastates the circulatory system.  

  

At birth, a mother’s hormones stop being passed to baby and the DA begins to close.  The body gets less and less oxygen.   In d-TGA, instead of operating as an entire system, the heart operates as two closed loops.  The blue blood enters the heart on the right side and is immediately sent back out to the body through the Aorta.  On the left, blood rich in oxygen from the lungs enters the left and is sent directly back to the lungs.  The result is the body’s tissues are never oxygenated and the lungs receive blood at high pressure.   Without surgery, death is near certain by one year of age.

While Alexander was born with this condition, because of his other defects, d-TGA was not able to leave his body with no oxygen.

Dual Superior Vena Cava (SVC)

Because of Alexander’s heterotaxy, many structures that normally occur on the right are copied onto the left.  The SVC is the major vessel that drains all of the blood from the upper part of the body (from the heart up) back to the heart so it can be re-oxygenated.  It connects to the right atrium.  

Alexander also has one on his left side.  It connects into the left atrium much like the other side.  There was one small bridging vessel between the right and left SVCs.  The left SVC is problematic because it would return blue blood to the side of the heart that deals with red.  Instead of being able to head to the lungs and exchange its carbon dioxide for oxygen, it would simply mix with red blood and head out to the body.

Those are three of Alexander’s heart defects; he has five others.  Like all of his heterotaxy brothers and sisters, his anatomy is complicated.  In the interest of keeping blog sizes manageable, I’ll save those for later.

***I am not a nurse or doctor, nor have I received any formal medical training.  Any and all medical related information on Alexander’s Fight is the product of a mother’s desperation to understand and advocate for her child.  This series of notes is the culmination of countless hours of independent research and medical consultation and is meant only to communicate my understanding of Alexander’s condition.  It is not intended as medical advice.  As always, seek the advice of a qualified medical professional to explain your specific diagnosis.***