Could predicted post-pacing interval from theoretical mathematical formula replace the observed post-pacing interval in clinical practice?

Waldo and colleagues originally described entrainment in 1977 (1). The proposed criteria for the recognition of entrainment were proposed: (I) when pacing at a constant rate that is faster than the rate of the tachycardia and which fails to interrupt it, constant fusion beats in the electrocardiography (ECG) are demonstrated during pacing except for the last captured beat, which is not fused; (II) during a tachycardia, when pacing at two or more constant rates that are faster than the rate of the tachycardia but fails to interrupt it, there is the demonstration of constant fusion beats in the ECG at each rate, but different degrees of constant fusion at each rate (2,3); (III) during a tachycardia, when pacing at a constant rate that is faster than the rate of tachycardia and which interrupts it, there is the demonstration of localized conduction block to a site or sites for one beat followed by activation of that site or those sites by the next paced beat from a different direction are demonstrated and associated with a shorter conduction time (3); (IV) during a tachycardia, when pacing at two constant rates that are faster than the rate of tachycardia, but which fail to interrupt it, there is the demonstration of a change in conduction time to and electrogram morphology at an electrode recording site (4).