RESUMO
BACKGROUND: There is no definition for strain deformation values in relation to cardiorespiratory fitness (CRF) in different heart failure (HF) phenotypes. AIM: To identify the relationship between echocardiographic systolic function measurements and CRF in HF patients. METHODS: Systematic review and meta-analysis following the PRISMA recommendations. Studies reporting echocardiographic assessments of left ventricular global longitudinal strain (LVGLS), left ventricular ejection fraction (LVEF) and direct measurement of peak oxygen uptake (VO2peak) in HF patients with reduced or preserved LVEF (HFrEF, HFpEF) were included. The patients were divided into Weber classes according to VO2peak. RESULTS: Twenty-five studies involving a total of 2,136 patients (70.5% with HFpEF) were included. Mean LVEF and LVGLS were similar in HFpEF patients in Weber Class A/B and Class C/D. In HFrEF patients, a non-significant difference was found in LVEF between Weber Class A/B (30.2% [95%CI: 29.6 to 30.9%]) and Class C/D (25.2% [95%CI: 20.5 to 29.9%]). In HFrEF patients, mean LVGLS was significantly lower in Class C/D compared to Class A/B (6.5% [95%CI: 6.0 to 7.1%] and 10.3% [95%CI: 9.0 to 11.5%], respectively). The correlation between VO2peak and LVGLS (r2 = 0.245) was nearly twofold stronger than that between VO2peak and LVEF (r2 = 0.137). CONCLUSIONS: Low LVGLS values were associated with low CRF in HFrEF patients. Although a weak correlation was found between systolic function at rest and CRF, the correlation between VO2peak and LVGLS was nearly twofold stronger than that with LVEF, indicating that LVGLS may be a better predictor of CRF in patients with HFrEF.
RESUMO
We evaluated the effects of electroconvulsive shock (ECS) on the expression of two genes encoding 70 kDa stress proteins, in the rat brain. The study was carried out by in situ hybridization using oligonucleotide probes specific for either the constitutively expressed hsc73, or the strictly inducible hsp70 gene. Rats were submitted to single or repeated (7 days, one session for each day) sessions of Electroconvulsive Shock. Animals were sacrificed at various time after treatment. ECS enhanced the basal expression of hsc73 in limbic areas, such as dentate gyrus, CA3, and median habenular nucleus. ECS induced hsp70 mRNA, which was not detectable in control animals, specifically in the Dentate Gyrus. The effect was present 2 h following treatment. Both single and repeated ECS were similarly effective. The finding likely reflects neuroadaptive local changes associated with a generalized seizure activity.
