Background: Cardiac syndrome Y, coronary slow flow phenomenon (CSFP), or primary coronary slow flow was defined as delayed distal opacification of coronary arteries without significant narrowing with an incidence of 1 to 7 % and coronary angiography (CA) as the diagnostic gold standard. We aimed to evaluate patients with CSFP regarding prevalence, clinical presentation, risk profile, predictors, and angiographic findings. Methods: A single-center retrospective study screening all patients who underwent CA in Cath. Lab. in the period from January 2016 to June 2020. Out of 9351 cases screened, 162 patients who had CSFP were selected as the patients' group, and 3 other age and sex-matched control groups were selected (normal CA, isolated coronary artery ectasia, and significant atherosclerotic disease). Results: The prevalence of CSFP in our study was 1.73 %. CSFP group included 107 (66 %) males and 55 (34 %) females with mean age of 55.07 ± 9.57 years. Chronic coronary syndrome (CCS) was the most common presentation of CSFP patients (73.5 %). The left anterior descending artery was the most affected coronary by CSFP (93.8 %). Smoking, hypertension, positive family history of atherosclerosis, abnormal ECG, and CHA2DS2-VASc-HSF score are independent predictors of CSFP in comparison to patients with normal CA. Conclusions: CSFP is an important angiographic finding that should be suspected in middle-aged male patients with CCS and abnormal ECG. CHA2DS2-VASc-HSF score is a simple and clinical predictor of CSFP that can be easily calculated. Larger-scale studies are recommended to better characterize this entity.