Alterations in cardiac structure and function in a modified rat model of myocardial hypertrophy.

This study was aimed to establish a stable animal model of left ventricular hypertrophy (LVH) to provide theoretical and experimental basis for understanding the development of LVH. The abdominal aorta of male Wistar rats (80-100 g) was constricted to a diameter of 0.55 mm between the branches of the celiac and anterior mesenteric arteries. Echocardiography using a linear phased array probe was performed as well as pathological examination and plasma B-type natriuretic peptide (BNP) measurement at 3, 4 and 6 weeks after abdominal aortic constriction (AAC). The results showed that the acute mortality rate (within 24 h) of this modified rat model was 8%. Animals who underwent AAC demonstrated significantly increased interventricular septal (IVS), LV posterior wall (LVPWd), LV mass index (LVMI), cross-sectional area (CSA) of myocytes, and perivascular fibrosis; the ejection fraction (EF), fractional shortening (FS), and cardiac output (CO) were consistently lower at each time point after AAC. Notably, differences in these parameters between AAC group and sham group were significant by 3 weeks and reached peaks at 4th week. Following AAC, the plasma BNP was gradually elevated compared with the sham group at 3rd and 6th week. It was concluded that this modified AAC model can develop LVH, both stably and safely, by week four post-surgery; echocardiography is able to assess changes in chamber dimensions and systolic properties accurately in rats with LVH.

[Relationship of characteristic duration and magnitude of the oscillatory breathing related with exercise functional capacity in patients with chronic heart failure].

Objective: To find out the relationship between the duration and amplitude of oscillatory breathing (OB) and their exercise capacity in patients with chronic heart failure (CHF) we did this study. Methods: Two hundred and thirty-seven CHF patients performed a maximum incremental upright cycle ergometry cardiopulmonary exercise testing (CPET). Respiratory gas exchange was measured on a breath-by-breath basis throughout the test. OB was defined as 3 or more continuous cycle fluctuations of ventilation during CPET, and the amplitude of VE oscillations exceed 25% of concurrent mean value. The CHF patients with OB (OB+) were divided into 3 sub-groups according to their Peak VO2. Group1 (mild OB+) Peak VO2 of ≥16 ml/min/kg, group 2 (moderate OB+) Peak VO2 is between 12~16 ml/min/kg, group 3 (severe OB+) Peak VO2 ≤ 12 ml/(min·kg). Results: There were 78(32.6%) patients detected as OB+ in 237 CHF patients. Among OB+ patients, OB duration in s related negatively to Peak VO2 in mL/min/kg (r=-0.82), Peak VO2 in %pred (r=-0.65), VO2 at AT (r=-0.78), and related positively to VE/VCO2 at AT (r=0.61). Conclusion: OB duration is related negatively to exercise capacity of CHF patients.