Cardiac phase-targeted dynamic load on left ventricle differentially regulates phase-sensitive gene expressions and pathway activation

Each heart was assigned to one of the following three conditions: phasic systolic overload (SO), phasic diastolic overload (DO), and no loading throughout the cardiac cycle (control; CN). We created SO by isovolumic contraction (peak systolic LVP > 170 mmHg) at a constant diastolic volume with end-diastolic pressure (EDP) equals 0 mmHg. For DO, we increased LVV in diastole so that EDP reached 40 mmHg, and unloaded quickly in systole to minimize LVP generation. At the end of 3 hours, the myocardium from each heart was collected for subsequent analyses. rat heart subjected to phasic systolic overload and diastolic overload