Background: Impaired microcirculation in acute coronary syndrome (ACS) patients manifests inadequate recovery and adverse clinical outcome. Here, we analyzed correlations between peripheral microcirculation and heart function in ACS patients. Methods: Opisthenar microvessel area (OMA) were measured with optical coherence tomography angiography (OCTA), cardiac functional indexes (echocardiograph) were assessed 48–72 h after therapeutic interventions. Results: Results showed that OMA normalized with heart rate (OMA-HR) were significantly greater in ACS patients with percutaneous intervention (ACS-PCI, n = 25, stenosis >80%) compared to those with pharmacological intervention (ACS-PI, n = 23, stenosis <50%, p =.02). Ejection fraction (EF) and fractional shortening (FS), which were not different between two groups, showed negative correlations with OMA-HR in ACS-PCI (EF: r = −0.512, p =.009; FS: r = −0.594, p =.002). Cardiac output (CO) inversely correlated with OMA-HR in both groups (r = −0.697, p <.0001; r = −0.527, p =.01). Neutrophil to lymphocyte ratio (NLR) on admission was greater in ACS-PCI group. NLR, which was negatively associated with EF or FS, was positively associated with OMA-HR in all patients. The area under the curve (AUC) for OMA-HR was 0.683 (specificity 0.696 and sensitivity 0.72, p =.02). OMA-HR at >376.5 μm2 predicts reduced FS and CO (p =.002, p =.005, respectively). Summary OMA-HR predicts inadequate recovery of the heart in severe ACS patients post-PCI.