TY - JOUR
T1 - Larger cell size in rabbits with heart failure increases myocardial conduction velocity and QRS duration
AU - Wiegerinck, Rob F.
AU - Verkerk, Arie O.
AU - Belterman, Charly N.
AU - van Veen, Toon A. B.
AU - Baartscheer, Antonius
AU - Opthof, Tobias
AU - Wilders, Ronald
AU - de Bakker, Jacques M. T.
AU - Coronel, Ruben
PY - 2006
Y1 - 2006
N2 - BACKGROUND: Patients with heart failure (HF) have an increased QRS duration, usually attributed to decreased conduction velocity (CV) due to ionic remodeling but which may alternatively result from increased heart size or cellular uncoupling. We investigated the relationship between QRS width, heart size, intercellular coupling, and CV in a rabbit model of moderate HF and in computer simulations. METHODS AND RESULTS: HF was induced by pressure-volume overload. Heart weight (21.1+/-0.5 versus 10.2+/-0.4 g, mean+/-SEM; P <0.01) and QRS duration (58+/-1 versus 50+/-1 ms; P <0.01) were increased in HF versus control. Longitudinal CV (thetaL; 79+/-2 versus 67+/-4 cm/s; P <0.01) and transversal subepicardial CV (thetaT; 43+/-2 versus 37+/-2 cm/s; P <0.05) were higher in HF than in controls. Transmural CV (thetaTM) was unchanged (25+/-2 versus 24+/-1 cm/s; P=NS). Patch-clamp experiments demonstrated that sodium current was unchanged in HF versus control. Immunohistochemical experiments revealed that connexin43 content was reduced in midmyocardium but unchanged in subepicardium. Myocyte dimensions were increased in HF by approximately 30%. Simulated strands of mammalian ventricular cells (Luo-Rudy dynamic model) revealed increased thetaL and thetaT with increased myocyte size; however, increased CV could not compensate for increased strand size of longitudinally coupled cells, and consequently, total activation time was longer. CONCLUSIONS: Increased myocyte size combined with the observed expression pattern of connexin43 yields increased thetaL and thetaT and unchanged thetaTM in our nonischemic model of HF. A hypertrophied left ventricle together with insufficiently increased thetaL and unaltered thetaTM results in a prolonged QRS duration
AB - BACKGROUND: Patients with heart failure (HF) have an increased QRS duration, usually attributed to decreased conduction velocity (CV) due to ionic remodeling but which may alternatively result from increased heart size or cellular uncoupling. We investigated the relationship between QRS width, heart size, intercellular coupling, and CV in a rabbit model of moderate HF and in computer simulations. METHODS AND RESULTS: HF was induced by pressure-volume overload. Heart weight (21.1+/-0.5 versus 10.2+/-0.4 g, mean+/-SEM; P <0.01) and QRS duration (58+/-1 versus 50+/-1 ms; P <0.01) were increased in HF versus control. Longitudinal CV (thetaL; 79+/-2 versus 67+/-4 cm/s; P <0.01) and transversal subepicardial CV (thetaT; 43+/-2 versus 37+/-2 cm/s; P <0.05) were higher in HF than in controls. Transmural CV (thetaTM) was unchanged (25+/-2 versus 24+/-1 cm/s; P=NS). Patch-clamp experiments demonstrated that sodium current was unchanged in HF versus control. Immunohistochemical experiments revealed that connexin43 content was reduced in midmyocardium but unchanged in subepicardium. Myocyte dimensions were increased in HF by approximately 30%. Simulated strands of mammalian ventricular cells (Luo-Rudy dynamic model) revealed increased thetaL and thetaT with increased myocyte size; however, increased CV could not compensate for increased strand size of longitudinally coupled cells, and consequently, total activation time was longer. CONCLUSIONS: Increased myocyte size combined with the observed expression pattern of connexin43 yields increased thetaL and thetaT and unchanged thetaTM in our nonischemic model of HF. A hypertrophied left ventricle together with insufficiently increased thetaL and unaltered thetaTM results in a prolonged QRS duration
U2 - https://doi.org/10.1161/CIRCULATIONAHA.105.565804
DO - https://doi.org/10.1161/CIRCULATIONAHA.105.565804
M3 - Article
C2 - 16461816
SN - 0009-7322
VL - 113
SP - 806
EP - 813
JO - Circulation
JF - Circulation
IS - 6
ER -