title: Optical mapping of Langendorff-perfused human hearts: establishing a model for the study of ventricular fibrillation in humans.
abstract: Our objective was to establish a novel model for the study of ventricular fibrillation (VF) in humans. We adopted the established techniques of optical mapping to human ventricles for the first time to determine whether human VF is the result of wave breaks and singularity point formation and is maintained by high-frequency rotors and fibrillatory conduction. We describe the technique of acquiring optical signals in human hearts during VF, their characteristics, and the feasibility of possible analyses that could be performed to elucidate mechanisms of human VF. We used explanted hearts from five cardiomyopathic patients who underwent transplantation. The hearts were Langendorff perfused with Tyrode solution (95% O(2)-5% CO(2)), and the potentiometric dye di-4-ANEPPS was injected as a bolus into the coronary circulation. Fluorescence was excited at 531 +/- 20 nm with a 150-W halogen light source; the emission signal was long-pass filtered at 610 nm and recorded with a mapping camera. Fractional change of fluorescence varied between 2% and 12%. Average signal-to-noise ratio was 40 dB. The mean velocity of VF wave fronts was 0.25 +/- 0.04 m/s. Submillimetric spatial resolution (0.65-0.85 mm), activation mapping, and transformation of the data to phase-based analysis revealed reentrant, colliding, and fractionating wave fronts in human VF. On many occasions the VF wave fronts were as large as the entire vertical length (8 cm) of the mapping field, suggesting that there are a limited number of wave fronts on the human heart during VF. Phase transformation of the optical signals allowed the first demonstration ever of phase singularity point, wave breaks, and rotor formation in human VF. This method provides opportunities for potential analyses toward elucidation of the mechanisms of VF and defibrillation in humans.
authors: Division of Cardiology, University Health Network, Toronto General Hospital, 150 Gerrard Street W., Toronto, Ontario, Canada. k.nanthakumar@uhn.on.ca
authors: Kumaraswamy
authors: K
authors: Nanthakumar
authors: José
authors: J
authors: Jalife
authors: Stéphane
authors: S
authors: Massé
authors: Eugene
authors: E
authors: Downar
authors: Mihaela
authors: M
authors: Pop
authors: John
authors: J
authors: Asta
authors: Heather
authors: H
authors: Ross
authors: Vivek
authors: V
authors: Rao
authors: Sergey
authors: S
authors: Mironov
authors: Elias
authors: E
authors: Sevaptsidis
authors: Jack
authors: J
authors: Rogers
authors: Graham
authors: G
authors: Wright
authors: Rajesh
authors: R
authors: Dhopeshwarkar
mesh_terms: D000328:Adult; D018780:Body Surface Potential Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods*; D055095:Optics and Photonics; D010477:Perfusion; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*