Introduction:
Late gadolinium enhancement (LGE) has the potential to become an excellent technique in the diagnosis of right ventricular myocardial infarction (RVMI). However, the gold standard, pathological findings from patients, is still unavailable to validate the true value of LGE.
Hypothesis:
We hypothesized that LGE might correspond with histological infarction in RVMI.
Methods:
36 transplant candidates (35 M /1F) with chronic ischemic heart disease were studied prospectively with LGE. According to the 12-segment-model, the pathological findings of RV were compared with the previous in vivo LGE after heart transplantation.
Results:
Histological RVMI was detected in 7 patients, and corresponded with all LGE segments (n=23) and 2 non-LGE segments. A generalize linear mix effect model showed non-significant difference (P=0.152) between the results of LGE and histological infraction. In identifying the RV segments with histological infarction, sensitivity and specificity of LGE was 92.0% (95%CI 74.0% to 99.0%) and 100% (95%CI 99.9% to 100.0%), respectively. Furthermore, RV segments without LGE mainly included two pathological patterns: histologically normal myocardium (n=372) or the admixture of viable myocardium and scattered replacement fibrosis (n=35). In the non-LGE RV segments, wall motion abnormality was associated with volume fraction of collagen (11.4±6.5% vs 4.3±2.2%, P<0.001) and the presence of ischemia (96.4% vs 1.7%, P<0.001).
Conclusions:
The RV segments with LGE corresponded closely with histological infarction in ischemic heart disease. However, RV segments without LGE might be histologically normal myocardium or intermixed with scattered replacement fibrosis. Further studies are required to evaluate the significance of scattered replacement fibrosis in the non-LGE segments.