Free-breathing continuous acquisitions, so called free-running, enable 3D whole-heart coverage for motion-resolved functional cardiac MRI. In prior work approaches based on 3D radial imaging were proposed with scan times of ~10-15min which also require computationally demanding reconstructions. In this work, we propose a 3D Cartesian free-running water-selective sequence that provides isotropic 3D whole-heart CINE imaging in <2min. Data is acquired with a variable-density spiral-like 3D Cartesian out-inward sampling and sequence-adaptive tiny-golden and golden angle increment. Respiratory motion-corrected and cardiac motion-resolved CINE images are obtained from a multi-bin-PROST reconstruction which exploits spatial-temporal redundancies. High agreement to conventional 2D CINE was observed.