A randomized, double-blind, multi-centered, placebo-controlled trial to evaluate efficacy of shexiang tongxin dropping pills in patients with coronary slow flow phenomenon

INTERVENTION: test group:Take 4 Shexiang Tongxin dropping pills sublingually after coronary artery angiography (CAG), repeat CAG 5 minutes after the pills melt. Then take 2 pills each time, 3 times a day, for 28 days.;control group:Take 4 placebo pills sublingually after coronary artery angiography (CAG), repeat CAG 5 minutes after the pills melt. Then take 2 pills each time ,3 times a day, for 28 days.; CONDITION: Coronary Heart diseases PRIMARY OUTCOME: Corrected TIMI frame count (CTFC); SECONDARY OUTCOME: ECG;seattle angina questionnaire;major adverse cardiac events(MACE); INCLUSION CRITERIA: (1) aged 18‐75 years; (2) with angina or angina like symptoms, to be diagnosed as coronary heart disease and meeting the indication of coronary angiography; (3) diagnosed coronary slow flow in at least one of the main coronary arteries by coronary angiography.