FIGURE 2.

an example of normal coronary flow reserve in a healthy subject. Velocity patterns are registered by pulsed‐wave Doppler. Resting laminar peak diastolic velocity in normal coronary artery is from 0.21 ± 0.08 m/s to 0.28 ± 0.09 m/s, and the velocity will not exceed 1 m/s even in case of its three‐ fourfold increase in the stenosis site. CFR is expressed as the ratio of coronary flow velocity under maximal vasodilatation to coronary flow velocity at rest. In this case, the basal peak diastolic flow velocity is normal, and it increases more than 2 times after dipyridamole, and therefore, CFR is normal. LV = left ventricle; Vp(d) = velocity peak (diastolic); CFVR = coronary flow velocity ratio