Radionuclide imaging in evaluation of left ventricular perfusion and function after percutaneous translumial septal myocardial ablation in patients with hypertrophic obstructive cardiomyopathy

Objective: To evaluate the clinical value of 99Tcm-methoxyisobutylisonitrile (MIBI) myocardial perfusion imaging (MPI) and equilibrium radionuclide angiography (ERNA) in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent percutaneous translumial septal myocardial ablation (PTSMA). Methods: Eight patients (5 men, 3 women) with symptomatic HOCM underwent rest 99Tcm-MIBI MPI and ERNA before and after PTSMA. The septal-to-lateral counts ratio and the extent of septal perfusion defect of the left ventricle were calculated from MPI. The left ventricular ejection fraction (EF), peak filling rate (PFR) and septal regional EF were measured from ERNA. Results: 99Tcm-MIBI MPI showed increased septal 99Tcm-MIBI uptake before PTSMA in all patients, and septal perfusion defects after PTSMA in 7 patients. The count-activity ratio of the septal-to-lateral wall decreased from 1.15 ± 0.11 to 0.76 ± 0.14 (P<0.01). The defect extent of the left ventricular septum was (6.42 ± 1.29)%. Furthermore, PFR increased significantly from (1.62 ± 0.28) EDVPs before PTSMA to (2.29 ± 0.24) EDVPs after PTSMA (P<0.01). The left ventricular septal regional EF decreased from (57 ± 7)% to (34 ± 9)% (P<0.01). However , left ventricular EF did not change significantly. Conclusion: MPI and ERNA are useful for the assessment of myocardial pefusion and the change of left ventricular function after PTSMA in patients with HOCM. (authors)