Todayโs path rounds are on ๐ฏ๐๐ง๐ญ๐ซ๐ข๐๐ฎ๐ฅ๐๐ซ ๐ฌ๐๐ฉ๐ญ๐๐ฅ ๐๐๐๐๐๐ญ๐ฌ! This topic inspired by the second year systemic pathology labs I helped out in this week 
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ง๐ญ๐ซ๐ข๐๐ฎ๐ฅ๐๐ซ ๐ฌ๐๐ฉ๐ญ๐๐ฅ ๐๐๐๐๐๐ญ๐ฌ are probably the most common developmental abnormality of the heart! In this disease, there is incomplete formation of the ๐ข๐ง๐ญ๐๐ซ๐ฏ๐๐ง๐ญ๐ซ๐ข๐๐ฎ๐ฅ๐๐ซ ๐ฌ๐๐ฉ๐ญ๐ฎ๐ฆ, which divides the two sides of the heart. ๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?Any species can get this condition!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
In normal embryonic development of the heart, the interventricular septum develops in 3 different parts: one grows up from the bottom of the heart, one grows downward from the top of the heart and one develops from a membrane running between these two points. If any of these segments has a problem during development, a ventricular septal defect can develop, which basically forms a hole in the interventricular septum. Typically, the most common location for these holes is in the โmiddleโ of the septum.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
The effect of these VSDs depends on the size and location of the holes. Typically, the biggest problem with these holes is it allows blood to flow from the left ventricle into the right ventricle during the normal contraction of the heart. This dumps a huge amount of blood into the right ventricle, which increases its workload immensely. At the same time, the left side of the heart has to take in a lot more blood with each contraction to maintain adequate blood flow to the body, since most of its blood flow is being redirected into the right ventricle. This ultimately results in ๐ก๐ฒ๐ฉ๐๐ซ๐ญ๐ซ๐จ๐ฉ๐ก๐ฒ (increased muscle size) of both sides of the heart, in order to try and compensate for its increased workload. Ultimately, this can lead to heart failure over time, which can have some serious consequences!
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Often the veterinarian will suspect a VSD based on listening to the animalโs heart, because it produces a characteristic heart murmur. To confirm the diagnosis in the live animal, an ๐๐๐ก๐จ๐๐๐ซ๐๐ข๐จ๐ ๐ซ๐๐ฆ (ultrasound of heart) is conducted in order to see the VSD.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Typically, smaller VSDs do not need to be treated, since they often do not cause issues for the animal. Larger VSDs can technically be treated by surgical repair, however this is often cost prohibitive in our pets and livestock species. Some studies have shown that ๐ฏ๐๐ฌ๐จ๐๐ข๐ฅ๐๐ญ๐จ๐ซ๐ฌ, which increase the diameter of vessels, can help reduce the amount of blood shunting through the heart, but often this is not sufficient for treatment.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-8) Many examples of ventricular septal defects!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 1. Sixth Edition.
Photos 1-2 ยฉ University of Calgary Diagnostic Services Unit.
Photos 3-8 ยฉ Noahโs Arkive contributors Miller, Leininger, Leipold, Morris licensed under CC BY-SA 4.0.
