title: Single-sensor system for spatially resolved, continuous, and multiparametric optical mapping of cardiac tissue.
abstract: BACKGROUND
  Simultaneous optical mapping of multiple electrophysiologically relevant parameters in living myocardium is desirable for integrative exploration of mechanisms underlying heart rhythm generation under normal and pathophysiologic conditions. Current multiparametric methods are technically challenging, usually involving multiple sensors and moving parts, which contributes to high logistic and economic thresholds that prevent easy application of the technique.
  
  
  OBJECTIVE
  The purpose of this study was to develop a simple, affordable, and effective method for spatially resolved, continuous, simultaneous, and multiparametric optical mapping of the heart, using a single camera.
  
  
  METHODS
  We present a new method to simultaneously monitor multiple parameters using inexpensive off-the-shelf electronic components and no moving parts. The system comprises a single camera, commercially available optical filters, and light-emitting diodes (LEDs), integrated via microcontroller-based electronics for frame-accurate illumination of the tissue. For proof of principle, we illustrate measurement of four parameters, suitable for ratiometric mapping of membrane potential (di-4-ANBDQPQ) and intracellular free calcium (fura-2), in an isolated Langendorff-perfused rat heart during sinus rhythm and ectopy, induced by local electrical or mechanical stimulation.
  
  
  RESULTS
  The pilot application demonstrates suitability of this imaging approach for heart rhythm research in the isolated heart. In addition, locally induced excitation, whether stimulated electrically or mechanically, gives rise to similar ventricular propagation patterns.
  
  
  CONCLUSIONS
  Combining an affordable camera with suitable optical filters and microprocessor-controlled LEDs, single-sensor multiparametric optical mapping can be practically implemented in a simple yet powerful configuration and applied to heart rhythm research. The moderate system complexity and component cost is destined to lower the threshold to broader application of functional imaging and to ease implementation of more complex optical mapping approaches, such as multiparametric panoramic imaging. A proof-of-principle application confirmed that although electrically and mechanically induced excitation occur by different mechanisms, their electrophysiologic consequences downstream from the point of activation are not dissimilar.
authors: Cardiac Mechano-Electric Feedback Lab, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
authors: Peter
authors: P
authors: Lee
authors: Christian
authors: C
authors: Bollensdorff
authors: T Alexander
authors: TA
authors: Quinn
authors: Joseph P
authors: JP
authors: Wuskell
authors: Leslie M
authors: LM
authors: Loew
authors: Peter
authors: P
authors: Kohl
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D056149:Epicardial Mapping / Q000379:methods*; D005260:Female; D006321:Heart / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology / Q000503:physiopathology*; D023421:Models, Animal; D051381:Rats; D017208:Rats, Wistar