Q&A: Dextrocardia

I’m not sure if you could help as this may be more medical but someone in a fight gets stabbed in the heart with the weapon left in the body and left for dead. Thing is, that’s not the heart because the victim has dextrocardia, in other words the heart is on the other side of the body. Can the victim survive this? Or would the attacker know they missed the heart. Or do most attackers want to miss the heart because they don’t want arterial spray all over?

That’s not how dextrocardia works. That’s not where your heart is.

Your heart is in the center of your chest, between, and behind, your lungs. The organ is asymmetrical, and the left side is responsible for pumping blood, meaning it is larger on that side. However, if you’re trying to stab someone in the heart, that’s going to be center mass. Dextrocardia or no, you’re going to hit their heart.

If, for some reason, you decided to skewer their pericardium, and could find that in battle, but they had dextrocardia, you’d still collapse their lung. It’s not like, “oh, yeah, that’s not where I keep my heart, I’m fine.” You would still seriously mess them up.

Incidentally, impaired cilia functionality is sometimes associated with dextrocardia. The lung’s cilia are “hair-like” tissues that assist with respiration, and help protect the lungs from infection. This means that the sufferer may experience reduced resistance to airborne bacterial and viral infection, and they may have difficulty getting sufficient oxygen. These have serious developmental implications.

Something I’m not entirely clear on is whether dextrocardia is merely associated with heterotaxy, or if it is a form of heterotaxy.

Heterotaxy is a catch all of genetic mutations where the subject’s internal organs either aren’t where they’re supposed to be, or are oriented differently from normal. This can be benign in rare cases, but those internal organs don’t, usually, function properly. Additionally, some organs can appear as multiple smaller variants (which don’t function properly), or an organ can be outright missing (with severe consequences.)

In the case of dextrocardia, a common form of heterotaxy is a missing spleen. You need that for your immune system, and it’s absence is a pretty big deal. This will often require the subject to supplement their immune system with antibiotics.

Additionally, dextrocardia is frequently associated with other heart defects. It makes sense that the heart might not be in working order, but this can get wild, including the ventricles being reversed, a perforated intraventricular septum (this is the tissue that separates the ventricles), failure of the heart’s walls to develop properly (or at all), the complete absence of a ventricle, (meaning the subject has a single ventricle heart), or having both the pulmonary artery and aorta connected to the right ventricle, with the left ventricle being basically unused.) All of these can result in poor circulation (at least), and saying, “what if they get stabbed there,” comes after a host of other symptoms.

Worse, with already poor circulation, a collapsed lung is significantly more dangerous, before we remember they’re probably immunocompromised. Yeah, that would still kill them. If both ports are on the right ventricle, this also means they’ll have abnormally high blood pressure in their lungs. That place they’re now bleeding from.

There is one, slightly less dire diagnosis, though it’s not dextrocardia. Situs inversus is a rare condition where all of the subject’s internal organs are “mirrored” from normal. The heart leans to the right, the right lung is smaller, the liver is left(ish), the spleen is on the right (and functional.) This is usually benign. It occurs in ~1:10,000 people, and can be the result of a recessive genetic mutation, or it can be a non-genetic result of an embryo splitting during gestation creating “mirror twins.” One of the twins may have reversed internal organs. Worth noting, most mirror twins do not exhibit situs inversus, it’s still a rare condition there. (Most mirror twins will have normal internal organ configurations.) Because it’s benign, it’s rarely diagnosed directly, and usually comes up when the subject is seeking medical attention for something else.

Basically medical trivia, but someone with situs inversus cannot have dextrocardia (as a disorder), and instead would have levocardia. This because the name, “dextrocardia,” includes the direction the heart is leaning. Situs inversus with levocardia is exceptionally rare. Though there are a few documented cases.

So, can it save your character? Even with situs inversus, your heart is in basically the same place. Getting stabbed on the “wrong” side would still collapse your larger lung, and either hit your heart (if they’re close to center mass), or (if they were a little low) your liver. So, no, it would never be, “oh I left my internal organs in my other chest,” it’d still be a lethal, or near lethal, chest wound.

-Starke

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