Basic concepts of optical mapping techniques in cardiac electrophysiology

Abstract

Optical mapping is a tool used in cardiac electrophysiology to study the heart's normal rhythm and arrhythmias. The optical mapping technique provides a unique opportunity to obtain membrane potential recordings with a higher temporal and spatial resolution than electrical mapping. Additionally, it allows simultaneous recording of membrane potential and calcium transients in the whole heart. This article presents the basic concepts of optical mapping techniques as an introduction for students and investigators in experimental laboratories unfamiliar with it.

Figure 1

First recording of calcium transients in intact heart loaded with Indo-1. Fluorescence increases at 400 ± 12.5 nm (top trace) and decreases at 550 ± 20 nm (bottom trace). In the middle trace, the first six beats of calcium transients were induced by pacing of right ventricle whereas the last four beats occurred spontaneously. The fluorescence was collected by fiber-optic cables before reaching photomultiplier tubes. The photomultiplier is a photodetector used when the light level is very low (Adapted from Lee et al., 1987). Reprinted with permission.

Figure 2

Simultaneous recording of membrane potential and calcium transients during normal sinus rhythm, ventricular fibrillation (VF), and defibrillation. (A) Optical signals from membrane potential and calcium transients during normal sinus rhythm. (B) Optical signals during VF, defibrillation and normal sinus rhythm in Langendorff-perfused rabbit heart (Attin, 2005).

Figure 3

Perrin-Jablonski diagram. S0 = ground state; S1 = excited state (Adapted from Jameson et al., 2003). Reprinted with permission.