Is I-123-beta-methyl-p-iodophenyl-methylpentadecanoic acid imaging useful to evaluate asymptomatic patients with hypertrophic cardiomyopathy? I-123 BMIPP imaging to evaluate asymptomatic hypertrophic cardiomyopathy.

Abstract

Myocardial imaging with I-123-beta-methyl-p-iodophenyl-methylpentadecanoic acid (BMIPP) is useful for predicting the outcome of patients with hypertrophic cardiomyopathy (HCM). But its usefulness in asymptomatic patients is unclear. Eighteen patients with asymptomatic HCM were examined with BMIPP and exercise stress perfusion imaging and then followed for 4.0 +/- 0.8 years. Extent of the defect (total defect score, TDS) and myocardial uptake of BMIPP (%uptake) were calculated to evaluate the BMIPP images. In the first study abnormal findings in the BMIPP and perfusion images were detected of 67 and 22% of the patients, respectively. In the second BMIPP study, the TDS had increased (2.1 +/- 2.7 to 4.1 +/- 4.9, p < 0.005) and the %uptake had decreased (5.67 +/- 0.88% to 4.81 +/- 0.91%, p < 0.001), but there were no differences in myocardial perfusion between the first and second study. Exertional dyspnea developed in 17% of the patients, and they were among the one third of the patients with the greatest reduction of %uptake. This group also showed deterioration of left ventricular (LV) %fractional shortening and LV volume in the second study. Abnormal findings on BMIPP images were frequently observed in patients with asymptomatic HCM, and these abnormal findings progressed with time. The greater reduction of %uptake during the follow-up period reflects the deterioration of the LV function.