What is the Value of Perfusion Scintigraphy and Cardiac PET in Hypertrophic Cardiomyopathy?

Abstract

Hypertrophic cardiomyopathy is the most common hereditary heart disease and affects about 1:500 individuals in the general population. Diagnosis is not always simple due to phenotypic variation and concomitance with other pathologies. It is initially based on electrocardiographic and echocardiographic criteria and on the absence of other diseases occurring with ventricular hypertrophy. Having myofibrillar derangement and fibrosis as a cellular base resulting in hemodynamic abnormalities, hypertrophic cardiomyopathy may reveal myocardial ischemia (not related to atherosclerosis) and sudden death. Therefore, evaluation of functional repercussion with myocardial perfusion scintigraphy using the Single Photon Emission Computed Tomography (SPECT) has gained space, since 25% of patients with hypertrophic cardiomyopathy have fixed or ischemic perfusion defects. In this context, some perfusion disorders are not necessarily associated with the type of hypertrophic cardiomyopathy, but are able to predict morbidity and mortality in these individuals. Another recent scintigraphy technique is the positron emission tomography (PET), which stands out in the evaluation of microcirculation, coronary flow reserve and myocardial metabolism. In patients with hypertrophic cardiomyopathy, studies have shown unfavorable results when myocardial blood flow and coronary flow reserve are lower. Metabolic myocardial evaluation using PET seems to be useful in the pathophysiological understanding of this disease and in the prognostic evaluation of alcohol ablation, a procedure performed in severe obstructive forms. This review addresses the role of nuclear cardiology using SPECT and myocardial PET in the diagnostic, prognostic and therapeutic evaluation of hypertrophic cardiomyopathy.