7 An increased resting coronary vasomotor tone in coronary resistance vessels has been reported and Sezgin et al. 6 It has been considered to be an early stage of atherosclerotic disease according to some studies. 5 It is defined as the delayed opacification of the coronary vasculature at the distal level in the absence of significant obstructive artery disease as a consequence of a primary coronary microvascular disorder. after they identified it in six patients. 2 There is still a great deal that is unknown about its nature and prognosis, which we cover in this review.ĬSF was first described in 1972 by Tambe et al. 3,4ĭifferent therapeutic options have been used and oral calcium channel blockers (CCBs) have proven to be the most effective as they attenuate the associated microvascular dysfunction.

Myocardial biopsy studies have demonstrated the presence of microvascular disease and an increased resting coronary vasomotor tone. Researchers have been trying to characterise this phenomenon and understand its pathophysiological mechanisms. The prevalence ranges from 1–5% of coronary angiograms and it is more frequent in young male smokers. 1 Far from being a simply angiographic finding, it has clinical implications, such as angina, acute coronary syndrome and sudden death.

Coronary slow flow (CSF) phenomenon, also known as cardiac syndrome Y, is characterised by angiographically normal or near-normal coronary arteries with delayed opacification of the distal vasculature.

Blood flow 7