No abstract

Ventricular activation time (AT [ms]) is the time required to activate the ventricle electrically. The in uences of AT on hemodynamics are of interest in clinical studies on methods for improving left ventricle (LV) function. However, the cardiovascular system is a dynamic system, in which many parameters are interrelated with each other, and teasing out the causality of the effects of AT within the system experimentally is dif cult. In this research, we focused on analyzing the effects of changing AT on hemodynamics using a hemodynamic model by incorporating a cardiac tissue model into an LV geometric model within a circulation model. The cardiac tissue model is constructed by connecting 10 cardiac cellular contraction models in the ber direction. In our cardiac tissue model, AT is represented by adding a constant delay time, δ delay [ms], to the starting times of calcium transients between adjacent contraction models. Thus, AT becomes δ delay × 9 [ms]. Simulations were performed under two conditions: normal AT (99 [ms], physiological); and prolonged AT (207 [ms], pathological). AT prolongation caused slight decreases in stroke volume (SV [mL]) and ejection fraction (EF [%]) by 2.10% and 6.00%, respectively, since both LV end-systolic and LV end-diastolic volumes increased by similar amounts. Maximum elastance (E max [mmHg/mL]) decreased by 15.4%. The maximum rate of LV pressure rise (max dp/dt [mmHg/ms]) decreased markedly by 43.7% at longer AT. The cellular mechanisms underlying changes in half sarcomere length were analyzed individually in 10 cells. Even though hemodynamic parameters did not change signi cantly, we concluded that large differences in cell behaviors existed.

Spontaneous coronary artery dissection (SCAD) is a relatively rare cause of acute coronary syndrome compared with atherosclerotic plaque rupture and predominantly occurs in young women. SCAD is associated with various conditions, such as emotional stress, pregnancy, hormonal therapy, collagen diseases, fibromuscular dysplasia, or vasospasm. Long-term cardiovascular events are common including the recurrence of SCAD. We report a case of SCAD with de novo recurrence at only 4 days after the first attack.

This report presents a rare case of acute decompensated heart failure with technetium-99m-pyrophosphate accumulation in extracardiac sites, such as chest and abdominal walls, in addition to intense myocardial uptake of the tracer. Subsequently, an abdominal fat pad fine-needle aspiration biopsy, which provided positive findings for transthyretin amyloidosis, was performed. ( Level of Difficulty: Advanced. )

The effects of epidermal growth factor (EGF) on ornithine decarboxylase (ODC) activity and DNA synthesis were studied during the perinatal period in rats. EGF administration to neonatal rats increased ODC activity and DNA synthesis in neonatal rat liver, but not in brain. EGF administration to maternal rats increased ODC activity in maternal rat liver, but not in rat placenta and fetal rat liver. These data suggest that EGF has mitogenic effects on neonatal and maternal rat liver and play some important roles in fetal and neonatal growth.