Regional differences in ventricular fibrillation in the open-chest porcine left ventricle.
It has been hypothesized that during ventricular fibrillation (VF), the fastest activating region, the dominant domain, contains a stable reentrant circuit called a mother rotor. This hypothesis postulates that the mother rotor spawns wavefronts that propagate to maintain VF elsewhere and implies that the ratio of wavefronts propagating off a region to those propagating onto it (propoff/propon) should be >1 for the dominant domain but <1 elsewhere. To test this prediction in the left ventricular (LV) epicardium of a large animal, most of the LV free wall was mapped with 1008 electrodes in 7 pigs. VF activation rate was faster in the posterior than in the anterior LV (10.0+/-1.3Hz versus 9.3+/-1.3Hz; P<0.001). The anterior LV had a higher fraction of wavefronts that blocked than did the posterior LV and had a propoff/propon ratio <1 (P<0.001). The mean conduction velocity vectors of the VF wavefronts pointed in the direction from the posterior to the anterior LV. Although these findings favor a dominant domain in the posterior LV, the facts that the anterior LV had a higher incidence of reentry than did the posterior LV and that the posterior LV did not have propoff/propon significantly different from 1 do not. Thus, quantitative regional differences are present over the porcine LV epicardium during VF. Although these differences are not totally consistent with the presence of a dominant domain within the LV free wall, the mean conduction velocity vector is consistent with one in the septum.
Nanthakumar
Kumaraswamy
K
University of Alabama at Birmingham, Birmingham, Ala 35294-0019, USA.
Huang
Jian
J
Rogers
Jack M
JM
Johnson
Philip L
PL
Newton
Jonathan C
JC
Walcott
Greg P
GP
Justice
Robert K
RK
Rollins
Dennis L
DL
Smith
William M
WM
Ideker
Raymond E
RE
D000818:Animals; D018780:Body Surface Potential Mapping; D006352:Heart Ventricles / Q000503:physiopathology*; D007700:Kinetics; D009206:Myocardium / Q000473:pathology; D010496:Pericardium / Q000503:physiopathology; D013552:Swine; D014693:Ventricular Fibrillation / Q000473:pathology / Q000503:physiopathology*