Phase Mapping of Cardiac Fibrillation: Applications in Studying Human Ventricular Fibrillation

The mechanisms responsible for the initiation and maintenance of ventricular fibrillation (VF) remain largely unknown. Most of the tools traditionally used to map the activation sequence of more stable arrhythmias cannot be used with fibrillation because of its unstable, chaotic behaviour. In the absence of traditional markers such as local activation time determination, novel techniques had to be developed to describe the electrical organisation or disorganization during VF. In this chapter we describe a technique known as phase mapping that was first used by basic scientists to study VF in cell cultures and isolated animal heart preparations. The chapter provides a brief overview of the technique and application to human VF. We present results obtained from clinical and experimental data demonstrating that both rotors and wave breaks coexist during VF. We conclude with a discussion on the limitations of the technique and potential clinical applications.