The impaired flow reserve capacity of penetrating intramyocardial coronary arteries in apical hypertrophic cardiomyopathy

Abstract

Coronary flow reserve (CFR) capacity of penetrating intramyocardial coronary artery (PICA) in apical hypertrophic (AH) cardiomyopathy has not been studied yet. We studied 65 patients with normal coronary angiogram results (mean age 56 +/- 10 years; 33 men, 32 women). Of these, 30 were normotensive without any left ventricular hypertrophy (control group), 24 had hypertension (HTN) without any left ventricular hypertrophy (HTN group), and 11 had AH cardiomyopathy (AH group). PICA-CFR and PICA-width ratio were calculated after the intravenous infusion of adenosine (140 microg/kg/min) just beneath the apical impulse window at a depth of 3 to 5 cm by using high-frequency transthoracic Doppler echocardiography. PICA-CFR was successfully measured in 59 (90.8%) of 65 patients. PICA-CFR was 1.65 +/- 0.49 in AH group, 2.50 +/- 0.77 in HTN group, and 2.42 +/- 0.73 in control group ( P < .005 vs HTN and control). PICA-width ratio was 1.45 +/- 0.42 in AH group, 2.14 +/- 0.72 in HTN group, and 1.81 +/- 0.55 in control group ( P = .025 vs HTN and control). PICA-CFR was closely related to width-ratio of PICA ( r = 0.448, P = .002). Conclusion PICA in AH has higher resting diastolic velocity, wider diameter, and impaired CFR compared with nonhypertrophied myocardium.