BACKGROUND: Sustained left ventricular (LV) dyssynchrony can lead to heart failure (HF) in the absence of coronary artery stenosis. We tested whether myocardial hibernation underlies the LV functional impairment caused by high-frequency pacing, an established model of nonischemic dilated cardiomyopathy. METHODS AND RESULTS: Regional LV contractile and perfusion reserve were assessed by magnetic resonance imaging, respectively, as end-systolic wall thickening (LVESWT) and myocardial perfusion reserve index (MPRI) at rest and during low-dose dobutamine stress (LDDS, 10 microg.kg.min intravenously for 10minutes) in failing minipigs (n=8). LV tissue was analyzed for glycogen deposits and other molecular hallmarks of hibernation. LDDS caused a marked increase in LVESWT (27+/-2.98 vs. 7.15+/-3 %, P < .05) and MPRI (2.1+/-0.5 vs. 1.3+/-0.3 P < .05) in the region that was activated first (pacing site) compared with the opposite region. Myocardial glycogen content was markedly increased in the pacing site (P < .05 vs. opposite region). In addition, gene expression of glycogen phosphorylase was reduced in pacing site compared with opposite regions (0.71+/-0.1 vs. 1.03+/-0.3, P < .05), whereas that of hexokinase type II was globally reduced by 83%. CONCLUSIONS: The combination of high heart rate and sustained dyssynchronous LV contraction causes asymmetrical myocardial hibernation, in absence of coronary artery stenosis.
BACKGROUND:Sustained left ventricular (LV) dyssynchrony can lead to heart failure (HF) in the absence of coronary artery stenosis. We tested whether myocardial hibernation underlies the LV functional impairment caused by high-frequency pacing, an established model of nonischemic dilated cardiomyopathy. METHODS AND RESULTS: Regional LV contractile and perfusion reserve were assessed by magnetic resonance imaging, respectively, as end-systolic wall thickening (LVESWT) and myocardial perfusion reserve index (MPRI) at rest and during low-dose dobutamine stress (LDDS, 10 microg.kg.min intravenously for 10minutes) in failing minipigs (n=8). LV tissue was analyzed for glycogen deposits and other molecular hallmarks of hibernation. LDDS caused a marked increase in LVESWT (27+/-2.98 vs. 7.15+/-3 %, P < .05) and MPRI (2.1+/-0.5 vs. 1.3+/-0.3 P < .05) in the region that was activated first (pacing site) compared with the opposite region. Myocardial glycogen content was markedly increased in the pacing site (P < .05 vs. opposite region). In addition, gene expression of glycogen phosphorylase was reduced in pacing site compared with opposite regions (0.71+/-0.1 vs. 1.03+/-0.3, P < .05), whereas that of hexokinase type II was globally reduced by 83%. CONCLUSIONS: The combination of high heart rate and sustained dyssynchronous LV contraction causes asymmetrical myocardial hibernation, in absence of coronary artery stenosis.
Authors: Guillaume Calmettes; Bernard Ribalet; Scott John; Paavo Korge; Peipei Ping; James N Weiss Journal: J Mol Cell Cardiol Date: 2014-09-26 Impact factor: 5.000
Authors: Dániel Czuriga; Attila Tóth; Eniko T Pásztor; Agnes Balogh; Andrea Bodnár; Eniko Nizsalóczki; Vincenzo Lionetti; Fabio A Recchia; István Czuriga; István Edes; Zoltán Papp Journal: Basic Res Cardiol Date: 2012-01-12 Impact factor: 17.165
Authors: Vincenzo Lionetti; Simone Lorenzo Romano; Giacomo Bianchi; Fabio Bernini; Anar Dushpanova; Giuseppe Mascia; Martina Nesti; Franco Di Gregorio; Alberto Barbetta; Luigi Padeletti Journal: PLoS One Date: 2013-11-19 Impact factor: 3.240