Tools and methods are particularly suited for certain cardiac conditions advantaged by pacing of the right and left ventricles from a lead in the right ventricle, e.g., to facilitate mechanically and/or electrically synchronous contractions for resynchronization. Certain aspects involve pacing and/or mapping by delivering pulses to a cardiac site useful for improving heart function as measured, e.g., by QRS width, fractionation, late LV activation timing, mechanical synchronicity of free wall and septal wall, effective throughput/pressure, or a combination thereof. Other specific aspects include: determining a pacing threshold, beyond the capture threshold, to improve heart function; delivering pulses of opposite polarity to achieve such heart-function improvement; bi-ventricular pacing from a lead in the right ventricle for such improved heart function; delivering pulses of opposite polarity at a site near the His bundle; electrode-based His-pacing, without penetrating the myocardium; generating and/or delivering multiple pacing profiles including a pacing profile that delivers pulses of opposite polarity and another pacing profile; delivering a pacing profile to generate a synchronous contraction of the septal wall and free wall of the LV from a RV pacing location; and treating one or more of distal LBBB and/or diffuse LBBB by pacing at a site near the His bundle.