TY - JOUR
T1 - Optical action potential upstroke morphology reveals near-surface transmural propagation direction
AU - Hyatt, Christopher J.
AU - Mironov, Sergey F.
AU - Vetter, Frederick J.
AU - Zemlin, Christian W.
AU - Pertsov, Arkady M.
PY - 2005/8/5
Y1 - 2005/8/5
N2 - The analysis of surface-activation patterns and measurements of conduction velocity in ventricular myocardium is complicated by the fact that the electrical wavefront has a complex 3D shape and can approach the heart surface at various angles. Recent theoretical studies suggest that the optical upstroke is sensitive to the subsurface orientation of the wavefront. Our goal here was to (1) establish the quantitative relationship between optical upstroke morphology and subsurface wavefront orientation using computer modeling and (2) test theoretical predictions experimentally in isolated coronary-perfused swine right ventricular preparations. We show in numerical simulations that by suitable placement of linear epicardial stimulating electrodes, the angle φ of wavefronts with respect to the heart surface can be controlled. Using this method, we developed theoretical predictions of the optical upstroke shape dependence on φ. We determined that the level VF* at which the rate of rise of the optical upstroke reaches the maximum linearly depends on φ. A similar relationship was found in simulations with epicardial point stimulation. The optical mapping data were in good agreement with theory. Plane waves propagating parallel to myocardial fibers produced upstrokes with V F*<0.5, consistent with theoretical predictions for φ>0. Similarly, we obtained good agreement with theory for plane waves propagating in a direction perpendicular to fibers (VF*>0.5 when φ<0). Finally, during epicardial point stimulation, we discovered characteristic saddle-shaped VF* maps that were in excellent agreement with theoretically predicted changes in φ during wavefront expansion. Our findings should allow for improved interpretation of the results of optical mapping of intact heart preparations.
AB - The analysis of surface-activation patterns and measurements of conduction velocity in ventricular myocardium is complicated by the fact that the electrical wavefront has a complex 3D shape and can approach the heart surface at various angles. Recent theoretical studies suggest that the optical upstroke is sensitive to the subsurface orientation of the wavefront. Our goal here was to (1) establish the quantitative relationship between optical upstroke morphology and subsurface wavefront orientation using computer modeling and (2) test theoretical predictions experimentally in isolated coronary-perfused swine right ventricular preparations. We show in numerical simulations that by suitable placement of linear epicardial stimulating electrodes, the angle φ of wavefronts with respect to the heart surface can be controlled. Using this method, we developed theoretical predictions of the optical upstroke shape dependence on φ. We determined that the level VF* at which the rate of rise of the optical upstroke reaches the maximum linearly depends on φ. A similar relationship was found in simulations with epicardial point stimulation. The optical mapping data were in good agreement with theory. Plane waves propagating parallel to myocardial fibers produced upstrokes with V F*<0.5, consistent with theoretical predictions for φ>0. Similarly, we obtained good agreement with theory for plane waves propagating in a direction perpendicular to fibers (VF*>0.5 when φ<0). Finally, during epicardial point stimulation, we discovered characteristic saddle-shaped VF* maps that were in excellent agreement with theoretically predicted changes in φ during wavefront expansion. Our findings should allow for improved interpretation of the results of optical mapping of intact heart preparations.
KW - Conduction velocity
KW - Optical action potential
KW - Optical mapping
KW - Voltage-sensitive dye
UR - http://www.scopus.com/inward/record.url?scp=23344433981&partnerID=8YFLogxK
U2 - 10.1161/01.RES.0000176022.74579.47
DO - 10.1161/01.RES.0000176022.74579.47
M3 - Article
C2 - 15994436
AN - SCOPUS:23344433981
SN - 0009-7330
VL - 97
SP - 277
EP - 284
JO - Circulation research
JF - Circulation research
IS - 3
ER -