Cine CMR is a routinely performed technique for heart anatomy and function analysis. In clinics, repeated breathholdings are performed to acquire multiple 2D slices to cover the whole heart, which further exacerbates the discomfort and challenges for young and severe-diseased patients. In this study, we halved the breathholding time for cine CMR using MB technique. Multiple sampling patterns were designed and studied for the best reconstruction quality. A NN leveraging the Siamese structure was designed to reconstruct the accelerated MB data and achieved great image quality.