The origin of the ectopic beats is usually from one of the three regions of fatty degeneration (the "triangle of dysplasia"): the RV outflow tract, the RV inflow tract, and the RV apex. Signal averaged ECG (SAECG) is used to detect late potentials and epsilon waves in individuals with ACM. Echocardiography
Echocardiography may reveal an enlarged, hypokinetic right ventricle with a paper-thin RV free wall. The dilatation of the RV will cause dilatation of the tricuspid valve annulus, with subsequent tricuspid regurgitation. Paradoxical septal motion may also be present. MRI
Fatty infiltration of the RV free wall can be visible on cardiac MRI. Fat has increased intensity in T1-weighted images. However, it may be difficult to differentiate intramyocardial fat and the epicardial fat that is commonly seen adjacent to the normal heart. Also, the sub-tricuspid region may be difficult to distinguish from the atrioventricular sulcus, which is rich in fat. Cardiac MRI can visualize the extreme thinning and akinesis of the RV free wall. However, the normal RV free wall may be about 3 mm thick, making the test less sensitive. Angiography
Right ventricular angiography is considered the gold standard for the diagnosis of ACM. Findings consistent with ACM are an akinetic or dyskinetic bulging localized to the infundibular, apical, and subtricuspid regions of the RV. The specificity is 90%; however, the test is observer dependent. Biopsy
Transvenous biopsy of the right ventricle can be highly specific for ACM, but it has low sensitivity.
See also
Neurofibromatosis
Noonan syndrome

References
External links

NSML at NIH/UW GeneTests
Gorlins syndrome II at Who Named It? DermAtlas 981603547
Dermnetnz
DermIS