Should a fixed external reference system be used to analyze left ventricular wall motion?

To investigate whether a fixed external reference system should be used to most accurately describe regional left ventricular wall motion, we used vectors to analyze a simple model of ventricular contraction. If measured in a fixed external reference system, motion of implanted radiopaque midwall markers may contain translational as well as contractile components. Therefore, comparisons of different reference systems that use marker motion measured in a fixed reference system as a standard will be biased unless proper corrections are included. We conclude that evidence to data does not indicate that the use of a fixed reference system is superior to other methods for analyzing regional ventricular wall motion.