Cardiomyopathies cover a lot of territory, from dilated to hypertrophic. Think of the heart as having a wiring system, just like your house. Everything works on electricity; it is just bioelectric which is much slower. The impulses travel from cell to cell as opposed to a wire. Further, there are two nodes that these impulses must travel through, the SA and AV nodes
Whenever there is a disease of the heart, there also can be malfunctions of this wiring system, creating “short circuits” in that wiring that lead to arrhythmia problems.
For instance, if the heart is overly dilated and the muscle fiber is stretched to its’ maximum, this may disrupt conduction through the muscle fibers. If the heart is overtly muscular as a result of volume of pressure difficulties, the same may occur.
They are strictly defined in terms of ventricular morphology, and consist of four major types: Dilated, hypertrophic, restrictive and arrhythmogenic (RV cardiomyopathies). There are other types, but these are the most recognizable variants.
Arrhythmogenic RV cardiomyopathy is characterized by a myocardial disease in which the muscular portions (myocardium) are replaced by fibrous tissue and fat, and can be regional or expand to other areas of the heart.
Prevalence is about 3% of all cardiomyopathies.
It usually begins asymptotically, and progresses to symptomatic electrical abnormalities due to fibro-fatty infiltration of the myocardium, especially on the right side. Eventually, this can cause bi-ventricular failure.
Sudden cardiac death can occur at any stage of this disease.
This is typically an inherited disease. In its’ early stages, it usually infiltrates the RV, infundibulum, apex and RVOT, and then may progress to the left ventricular region. The first symptoms are often sudden cardiac death all the way to puberty, but patients may also experience syncopal episodes in the months preceding their death.
There really is no test for this abnormality aside from EKG findings such as inverted T waves and RBBB. Signal averaged EKG is often valuable in the detection of this disease. EKG abnormalities seem to be the best approach to detecting this disease, such as distinctive ventricular arrhythmias.
Echo findings include the exclusion of partial anomalous venous return and Ebstein’s. Look for RV dilatation and hypokenesia, aneurisms, regional wall motion variations and hyertrabeculation.
Treatment involves the use of beta blockers and treatments for cardiac failure. Some patients may require transplantation. High risk patients should be offered defibrillators. Prophylaxis however, is the primary treatment as of this writing.
Ken Heiden RDCS, RVT, PE