Coronary artery-left ventricular shunt: an important cause of chest pain in patients with hypertrophic cardiomyopathy.

The influence of shunts between the coronary artery (CA) and the left ventricle (LV), on chest pain (CP) in patients with hypertrophic cardiomyopathy (HCM) is unknown. We examined the incidence of CA-LV shunts and their influence on CP in HCM patients. Twenty normal control subjects (NCS), 3 with CP due to CA-LV shunts (CP patients), and 60 with HCM participated. Interventricular septal wall thickness (IVST), LV posterior wall thickness (LVPWT), cardiac and stroke indexes (CI and SI), LV end-diastolic pressure (LVEDP), and proximal diameters of the CA were measured. Twenty-five HCM patients had a CA-LV shunt (41.7%). Both IVST and LVPWT were greater in the HCM patients than in NCS and CP patients. These values showed no significant differences between the HCM with shunt and HCM without shunt groups. CI and SI were lower in the HCM patients than in NCS and CP patients. LVEDP was higher in the HCM and CP patients than in NCS. CA diameters were larger in the HCM and CP patients than in NCS. CP was found in 32 HCM patients (53%). The incidence of CP was greater in the HCM with shunt group than in HCM without shunt group (80 vs. 34%, p < 0.0005). There was no significant difference in CA diameters between the HCM patients with CP and those without CP. CA-LV shunts are often found in HCM patients and are closely related to CP. Thus, CA-LV shunts are an important factor behind CP in HCM patients.