Severe Mechanical Dyssynchrony Causes Regional Hibernation-Like Changes in Pigs With Nonischemic Heart Failure

Abstract 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 μg·kg·min intravenously for 10 minutes) 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 P P P Conclusions The combination of high heart rate and sustained dyssynchronous LV contraction causes asymmetrical myocardial hibernation, in absence of coronary artery stenosis.