Background: Coronary flow reserve (CFR) capacity of penetrating intramyocardial coronary artery (PICA) in apical hypertrophic (AH) cardiomyopathy has not been studied yet.
Methods: 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.
Results: 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.