Patent ID: 7440803

Claim:
A machine-assisted method comprising: measuring a first impedance signal, the first impedance signal being substantially indicative of a volume of a first ventricle of a heart as the first ventricle expands and contracts during a cardiac cycle of the heart; measuring a second impedance signal, the second impedance signal being substantially indicative of a volume of a second ventricle, different from the first ventricle, as the second ventricle expands and contracts during the same cardiac cycle; forming a function that parameterizes the first impedance signal as the function of the second impedance signal during the same cardiac cycle, the forming the first function includes forming a Lissajous function that parameterizes the first impedance signal as the function of the second impedance signal during the same cardiac cycle, the Lissajous function enclosing a loop area during the cardiac cycle; and computing an indication of a degree of synchrony or asynchrony between the right and left ventricles using an indication of the loop area wherein computing the degree of synchrony or asynchrony includes: computing a rectangular area defined by maximum and minimum impedances of each of the first and second ventricles during the cardiac cycle; and computing a synchronization fraction by forming a difference of the rectangular area less the loop area, and dividing the difference by the rectangular area.