Coronary slow flow: Description of a new “cardiac Y” syndrome Massimo Fineschi, Tommaso Gori  International Journal of Cardiology  Volume 137, Issue 3, Pages 308-310 (November 2009) DOI: 10.1016/j.ijcard.2008.05.076 Copyright © 2008 Elsevier Ireland Ltd Terms and Conditions

Fig. 1 Quantification of coronary resistances using the thermodilution wire (modified). The wire allows measurement of thermodilution curves and calculation of the mean transit time (Tmn) of an intracoronary bolus of saline. Tmn is measured three times at rest (blue arrow and box) and after intracoronary injection of 15 mg papaverine (yellow box)(2). An index of microvascular resistances is calculated (e.g., resting resistances are calculated as resting Tmn⁎resting mean pressure, indicated by the green arrow) at rest and during hyperemia. Coronary flow reserve (CFR) is calculated as the ratio of resting to hyperemic Tmn. In slow flow (“syndrome Y”) patients, resting resistances are elevated while CFR is preserved. In contrast, typical cardiac syndrome X has normal resting resistances but reduced CFR. Pd=mean blood pressure measured near the tip of the pressure wire (green); Pa=mean blood pressure at the catheter tip; FFR=fractional flow reserve (ratio of catheter Pd/wire Pd during hyperemia; a value >0.75 indicates the absence of hemodynamically significant epicardial stenosis) (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) International Journal of Cardiology 2009 137, 308-310DOI: (10.1016/j.ijcard.2008.05.076) Copyright © 2008 Elsevier Ireland Ltd Terms and Conditions