Validation of the local shortening function as assessed by nonfluoroscopic electromechanical mapping: a comparison with computerized left ventricular angiography

Background: Nonfluoroscopic electromechanical mapping (NEM) has been proposed as a new technique for the evaluation of electrical and mechanical functioning of the myocardium. In this system, linear local shortening (LLS) is the parameter used for assessment of local mechanical properties. To validate this parameter, we compared LLS with regional wall motion (RWM) data derived from contrast left ventriculograms acquired in the same patients. Methods and results: Angiographic left ventricular RWM was analyzed using the area–length method. The right anterior oblique view was divided in five segments, the left anterior oblique view in two. Through a comparison of enddiastolic and endsystolic areas drawn from a computer-defined central point to the respective wall delineation, RWM was calculated as change in area. In the first approach, we compared area changes to comparable NEM segments. In the second part of the study, LLS values for normokinetic, hypokinetic, akinetic and dyskinetic segments were correlated to the change in angiographic RWM. In the first approach, the overall comparison of segments yielded a correlation coefficient of 0.67 (P<0.0005). In the second part of the study, differences in LLS values between dyskinetic (LLS=−3.68±8.86%), akinetic (2.84±3.96%), hypokinetic (9.35±4.27%) and normokinetic (13.66±7.98%) segments were highly significant (overall ANOVA: P<0.0005). Conclusion: NEM is a powerful tool for invasive electromechanical assessment of myocardial function.