Microgrooved thin PLGA film (≈30 μm) is successfully fabricated on a Teflon mold, which could be readily peeled off and is used for the construction of a biomimetic cardiac patch. The contraction of it is studied with optical mapping on transmembrane action potential. Our results suggest that steady-state contraction could be easily established on it under regular electrical stimuli. Besides, the biomimetic cardiac patch recapitulates the anisotropic electrophysiological feature of native cardiac tissue and is much more refractory to premature stimuli than the random one constructed with non-grooved PLGA film, as proved by the reduced incidence of arrhythmia. Considering the good biocompatibility of PLGA as demonstrated in our study and the biodegradability of it, our biomimetic cardiac patch may find applications in the treatment of myocardial infarction. Moreover, the Teflon mold could be applied in the fabrication of various scaffolds with fine features for other tissues.