A 61-year-old gentleman with previous anterior myocardial infarction 20 years ago and recent coronary bypass surgery 15 months ago presented with palpitations and frequent ventricular ectopics on a 24-h Holter monitor. Electrocardiography showed a QRS duration of 102 ms. Cardiac magnetic resonance imaging showed a left ventricular ejection fraction of 35%. It demonstrated an extensive area of lipomatous metaplasia in the region of previous infarction (Panels A–D).
This extensive adipose deposition in the chronic infarct region highlights that lipomatous metaplasia in the healed infarct can occur and is more prevalent than we recognize. Complex fibrotic scars can provide critical substrates for ventricular arrhythmia; however, the prognosis of ‘fatty metaplasia’ is unknown. The infiltrative presence of adipose tissue and fibrous tissues within the myocardium is known to be the pathological culprit in arrhythmogenic right ventricular cardiomyopathy, which is sometimes associated with left ventricular involvement. Studies which associated post-infarct ventricular arrhythmia and mortality risks with the presence of ‘grey zone’ (an area arbitrarily defined with a signal-intensity between the scar core and remote healthy myocardium on late gadolinium enhanced, LGE, images) in the peri-infarct region may un-intentionally encompass adipose tissue within the ‘grey zone’, given the similar ‘grey’ signal intensity of adipose tissue on LGE images. Current guidelines on implantable defibrillator device ICD therapy recommendation do not incorporate scar heterogeneity assessment and do not provide a clear-cut consensus in this individual case. An ICD was implanted for primary prevention with the involvement of the patient choice in this case.
Cine steady-state free precession images in long-axis, three-chamber, and short-axis views (Panels A and B) demonstrated an aneurysmal apex, and akinetic anterior and antero-septal walls with an additional high-signal-intensity area beyond a black boundary artifact within the subendocardium (Supplementary data online, Video S1 and Supplementary Data). Isotropic high-resolution (1.7 × 1.7 × 1.7 mm) three-dimensional late-gadolinium-enhanced images showed a rim of scar endocardially in the same region (Panel C), but could not account for the degree of transmural extension seen. T1-weighted (Panels D1 and D2) and T2-weighted (Panels D2 and D4) black-blood images without (Panels D1 and D3) and with (Panels D2 and D4) fat-suppression revealed that the region represented adipose tissue (arrows).
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Supplementary data are available at European Heart Journal - Cardiovascular Imaging online.
