UNIT 12.17 Simultaneous Optical Mapping of Intracellular Free Calcium and Action Potentials from Langendorff Perfused Hearts

  1. Guy Salama,
  2. Seong-min Hwang

Published Online: 1 JUL 2009

DOI: 10.1002/0471142956.cy1217s49

Current Protocols in Cytometry

Current Protocols in Cytometry

How to Cite

Salama, G. and Hwang, S.-m. 2009. Simultaneous Optical Mapping of Intracellular Free Calcium and Action Potentials from Langendorff Perfused Hearts. Current Protocols in Cytometry. 49:12.17:12.17.1–12.17.32.

Author Information

  1. University of Pittsburgh, Pittsburgh, Pennsylvania

Publication History

  1. Published Online: 1 JUL 2009
  2. Published Print: JUL 2009


The cardiac action potential (AP) controls the rise and fall of intracellular free Ca2+ (Cai), and thus the amplitude and kinetics of force generation. Besides excitation-contraction coupling, the reverse process where Cai influences the AP through Cai-dependent ionic currents has been implicated as the mechanism underlying QT alternans and cardiac arrhythmias in heart failure, ischemia/reperfusion, cardiac myopathy, myocardial infarction, congenital and drug-induced long QT syndrome, and ventricular fibrillation. The development of dual optical mapping at high spatial and temporal resolution provides a powerful tool to investigate the role of Cai anomalies in eliciting cardiac arrhythmias. This unit describes experimental protocols to map APs and Cai transients from perfused hearts by labeling the heart with two fluorescent dyes, one to measure transmembrane potential (Vm), the other Cai transients. High spatial and temporal resolution is achieved by selecting Vm and Cai probes with the same excitation but different emission wavelengths, to avoid cross-talk and mechanical components. Curr. Protoc. Cytom. 49:12.17.1-12.17.32. © 2009 by John Wiley & Sons, Inc.


  • action potential (AP);
  • intracellular free Ca2+ (Cai);
  • photodiode array (PDA);
  • complementary metal oxide silicon (CMOS) camera;
  • Voltage Sensitive Dye (VSD);
  • Cai indicator;
  • Rhod-2AM;
  • Pittsburgh I (PGH I);
  • RH237