Chest pain and myocardial ischemia are prevailing features in patients with hypertrophic cardiomyopathy (HCM). Recently introduced single-photon emission computed tomography (SPECT) cameras with solid-state cadmium-zinc-telluride (CZT) detectors have been shown to decrease imaging time and improved the imaging quality of gated myocardial perfusion imaging (MPI). The investigators also correlate the MPI parameters with echocardiographic parameters. This study is to examine the spatial distribution of stress perfusion abnormalities and tissue injury in patients with HCM using a CZT SPECT camera.

The investigators will retrospectively evaluate myocardial perfusion patterns and cardiac function with Thallium (Tl)-201 gated dipyridamole MPI in patients with clinical diagnosis of HCM and patent coronary angiography between January 2013 and October 2016. The inclusion criteria included a spade-like configuration on left ventriculogram, or echocardiographic findings suggestive of HCM. The participants will be then divided into the following three groups: apical, concentric and septal forms. Regional perfusion would be analyzed using a 17-segment model from 0-4 degree (0=normal, to 4=absent perfusion); and summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS) were calculated. Gated SPECT would be processed by quantitative gated SPECT (QGS) software (Cedars-Sinai Medical Center, Los Angeles, CA, USA) and ejection fraction phase analysis. Diastolic parameters would be also acquired by Doppler echocardiography, and correlated with MPI parameters.

Inclusion Criteria:

• clinical diagnosis of HCM and patent coronary angiography between January 2013 and October 2016.

Exclusion Criteria:

• patient with prior myocardial ischemia, conduction abnormality, valvular disease or other cardiomyopathy

HCM patients with patent coronary artery who underwent MPI