Table 2.

Non-substrate-based effects upon bipolar voltage (references are shown within the table)

Factor	Direction of effect on electrogram amplitude (theoretical/pre-clinical)	Direction of effect (clinical)	Clinical demonstration of effect	Reference
Non-parallel activation direction	Decrease	–	No	[17, 82]
Increasing angle of incidence	30° improves lesion diagnosis accuracy	–	No	[86]
Increasing electrode size	Variable dependent on tissue	Variable dependent on tissue	Yes	[19, 20]
Increasing electrode spacing	Increase	Increase	Yes	[17, 21]
Increasing tissue contact force	Increase	Increase at low contact force only	Yes	[23]
Bandpass filtering	Effect is based on which filter is applied	Increasing frequency of high pass reduces amplitude	Yes*	[24]

*Only for non-contact unipolar mapping