Coronary Slow Flow Phenomenon: A Narrative Literature Review

Coronary slow flow (CSF) is understood to be a clinical condition during which angiographic findings show the slowed filling of contrast in the coronary vasculature in individuals without a history of coronary artery disease (CAD). Other names for this entity include, less commonly, Syndrome Y and primary CSF. Though clinically underestimated, it is a recognized phenomenon and is documented in a subset of patients with symptoms resembling acute coronary syndrome. The most common group with CSF is that of young males with a history of smoking. CSF is clinically relevant, with patients presenting with chest pain, arrhythmias, and even sudden death. CSF therefore markedly impairs patients' quality of life. Particular treatments for CSF are not specified, though oral calcium channel blockers (CCBs) have been used successfully. Much research has been done regarding CSF, and it is thought to reflect endothelial dysfunction. Factors such as inflammation, atherosclerosis, hematological disorders, and structural components may also contribute to CSF's pathology, though CSF's exact cause is still not fully understood by clinicians. CSF is also distinct from conditions with similar presentations, such as post-procedural slow flow and vasospasm. Since the importance of CSF is being understood to be clinically relevant by clinicians, research is recommended to better further elucidate the pathology of this phenomenon.