Myocardial scintigraphy using 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) reveals a high incidence of reduced accumulation of the tracer in patients with hypertrophic cardiomyopathy (HCM). This defect is thought to reflect impairment of myocardial fatty acid metabolism. In this study, the distribution of BMIPP defects was characterized and correlated with the clinical features of patients with HCM.
Methods: Thirty patients with asymmetric septal hypertrophy (ASH) were examined. Regional BMIPP accumulation was evaluated. Each region was normalized to the accumulation in the nonhypertrophic lateral region, which was represented as 100% on each bull's-eye map. The corresponding thallium accumulation for, each region was then used to correct for the partial-volume effect.
Results: BMIPP accumulation was significantly less in the septal portion of the anterior wall (As), the septal portion of the posterior wall (Ps) and the apex than in the lateral segments. BMIPP defects were significantly more frequent in the As, Ps and apical segments (20.0%, 20.0% and 33.3%, respectively) and were present in the As or Ps segments in 8 patients (27%). The patients with BMIPP defects in the As or Ps segments had a more frequent family history of HCM or sudden death and severe cardiac dysfunction.
Conclusion: BMIPP defects occur predominantly in the As and Ps segments in some patients with ASH, which is often associated with severe cardiac dysfunction. The distribution of BMIPP defects may contribute to the classification of HCM and the assessment of its severity.