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 Ϯ 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 Ϯ 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.

Design and formulation of functional pluripotent stem cell-derived cardiac microtissues

“…Cardiomyopathic human heart during ventricular fibrillation 25 ± 4.0 [39] Access to robust and information-rich human cardiac tissue models would accelerate drug-based strategies for treating heart disease. Despite significant effort, the generation of high-fidelity adult-like human cardiac tissue analogs remains challenging.…”

Intramural Activation During Early Human Ventricular Fibrillation

“…Immobilization was performed only just before the images were acquired by holding the preparation between 2 clear Plexiglas sheets. 4 Fluorescence was excited at 531Ϯ20 nm (FF01-531/40-25; Semrock; Rochester, NY) with a 150-W halogen light source (MHF-G150LR; Moritex; Tokyo, Japan). The emission signal was long-pass filtered at 610 nm and recorded with a charge-coupled device and complementary metal-oxide semiconductor camera (Ultima; BrainVision; Morrisville, NC).…”

Theoretical considerations for mapping activation in human cardiac fibrillation

“…3 High resolution mapping techniques, especially ones using optical dyes, have proven to be instrumental in determining the spatio-temporal wave organization in animal models and in explanted human hearts. 4,5 Such models have shown that spatiotemporally variable AF may actually result from periodic sources in the form of spiral waves (electrical rotors) 6,7 or focal sources, in which activation spreads from an origin, 8 that are localized yet lie in unpredictable locations and thus are ideally identified using a wide field of view. In patients, optical techniques are not feasible due to the toxicity of dyes and, in the absence of other high resolution and wide field of view mapping studies, it is has not been defined to what extent animal data can be legitimately translated to humans.…”