TY - JOUR
T1 - Structure-related initiation of reentry by rapid pacing in monolayers of cardiac cells
AU - Bian, Weining
AU - Tung, Leslie
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2006/3
Y1 - 2006/3
N2 - This study examines how a zigzag pattern of conduction, a form of structural heterogeneity frequently found in old or diseased hearts, affects the vulnerability to reentry during rapid pacing. A central rectangular island (8X4 mm) containing a predefined zigzag pattern was created in cultured isotropic monolayers of neonatal rat ventricular myocytes. Impulse propagation was optically mapped from 253 sites using voltage-sensitive dye and was anisotropic within the zigzag island. With increasing interval between neighboring transverse connections (a), relative to the distance between longitudinal strands (b), transverse conduction velocity (CV) decreased to 66±6%, 20±2%, and 15±2% of CV in the surrounding isotropic region, whereas longitudinal CV increased to 102±8%, 113±12%, and 131±23% for a:b ratios of 1:1, 1:5, and 1:9, respectively. During rapid pacing, propagation distal to the island was steered from the side of the island with more transverse connections ("dominant" side) toward the side with fewer connections ("weak" side). Increased asymmetry in the pattern accentuated this effect, and resulted in increased rate-dependent differences in CV on the 2 sides. Consequently, a functional obstacle formed on the weak side, followed by development of single loop reentry. The reentrant wave revolved around a line of block defined by the border of the island. Reentry chirality was determined by the weak side location, and the pacing rate needed to initiate reentry decreased with increased asymmetry in the pattern. In conclusion, reentry is readily induced by rapid pacing in confluent cardiac cell monolayers containing a central and asymmetric island of zigzag conduction.
AB - This study examines how a zigzag pattern of conduction, a form of structural heterogeneity frequently found in old or diseased hearts, affects the vulnerability to reentry during rapid pacing. A central rectangular island (8X4 mm) containing a predefined zigzag pattern was created in cultured isotropic monolayers of neonatal rat ventricular myocytes. Impulse propagation was optically mapped from 253 sites using voltage-sensitive dye and was anisotropic within the zigzag island. With increasing interval between neighboring transverse connections (a), relative to the distance between longitudinal strands (b), transverse conduction velocity (CV) decreased to 66±6%, 20±2%, and 15±2% of CV in the surrounding isotropic region, whereas longitudinal CV increased to 102±8%, 113±12%, and 131±23% for a:b ratios of 1:1, 1:5, and 1:9, respectively. During rapid pacing, propagation distal to the island was steered from the side of the island with more transverse connections ("dominant" side) toward the side with fewer connections ("weak" side). Increased asymmetry in the pattern accentuated this effect, and resulted in increased rate-dependent differences in CV on the 2 sides. Consequently, a functional obstacle formed on the weak side, followed by development of single loop reentry. The reentrant wave revolved around a line of block defined by the border of the island. Reentry chirality was determined by the weak side location, and the pacing rate needed to initiate reentry decreased with increased asymmetry in the pattern. In conclusion, reentry is readily induced by rapid pacing in confluent cardiac cell monolayers containing a central and asymmetric island of zigzag conduction.
KW - Arrhythmia
KW - Cardiac electrophysiology
KW - Cell culture
KW - Optical mapping
KW - Reentry
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U2 - 10.1161/01.RES.0000209770.72203.01
DO - 10.1161/01.RES.0000209770.72203.01
M3 - Article
C2 - 16469953
AN - SCOPUS:33645286247
SN - 0009-7330
VL - 98
SP - e29-e38
JO - Circulation research
JF - Circulation research
IS - 4
ER -