The underlying rationale lies in the better approximation of the normal sequence of left ventricular activation, through use of two, instead of a single, pulses. According to trial results, one can achieve, compared to conventional CRT, improved coordination between left ventricular segments, improved cardiac output and, possibly, tissue perfusion, and potentially reduction of arrhythmia propensity (mechanism similar to that of CRT). Thus, it would be interesting to study whether these can be independently confirmed by changes in VAC values. In heart failure, VAC values increase considerably due to increases in Ea as a result of the feedback loop regarding pressure (but not volume) maintenance. As a consequence, any reduction would move them closed to both 1 and the 0.5-0.7 area, yielding improvement in both SW maximization and efficiency optimization.