Purpose: Myocardial ischemia is an important problem in hypertrophic cardiomyopathy. Stunning is an important mechanism in progressive dysfunction of the ischemic myocardium. In this report, the authors found prolonged myocardial stunning in a child with hypertrophic cardiomyopathy that was induced by dipyridamole stress on quantitative gated SPECT.
Materials and methods: A 6-year-old boy with septal hypertrophy underwent rest and dipyridamole stress gated myocardial SPECT. Software was used to quantify automatically segmental perfusion and function at rest and after stress.
Results: Perfusion imaging showed a reversible perfusion decrease in the hypertrophic septum. Cine-gated imaging of the septum showed dyskinesia and a severe abnormality of systolic thickening during the poststress period, whereas it showed nearly complete recovery at rest. Quantified regional perfusion and function indices also showed this perfusion decrease and myocardial dysfunction after dipyridamole stress.
Conclusion: In a child with hypertrophic cardiomyopathy, myocardial stunning was induced by dipyridamole stress, in accordance with decreased perfusion reserve.