Smart edge sensors for bio-signal monitoring must support complex signal processing routines within an extremely small energy envelope. Coarse-Grained Reconfigurable Arrays (CGRAs) are good candidates for tackling these conflicting objectives because, thanks to their flexibility and high computational density, they can efficiently support the computational hot-spots characterizing bio-DSP applications. The Interleaved- Datapaths (i-DPs) CGRA presented in this paper further leverages the benefits of this architectural paradigm, focusing on ultralow energy operation. Its defining feature is the complex design of its computing cells, which, by embedding multiple i-DPs, allow a high ratio between computing and control logic, effectively speeding up computations, and resulting in a marginal impact on the required IC area. Interleaved datapaths increase the energy efficiency of up to 33 %, with respect to a single-DP alternative, when executing common kernels in the multi-lead ECG signal processing field.