Correlation between Electrocardiographic Features and Mechanical Dyssynchrony in Heart Failure Patients with Left Bundle Branch Block

Background: Few electrocardiographic parameters beyond the QRS duration were studied with regard to the correlation with mechanical dyssynchrony. This study aims to analyze the correlation between electrocardiographic parameters and mechanical dyssynchrony in patients with symptomatic heart failure (HF) and left bundle branch block (LBBB). Methods: Patients with HF, ejection fraction ≤ 35%, and QRS interval ≥ 120 ms with a LBBB were prospectively studied. We analyzed the correlation between electrocardiographic parameters (QRS duration, R voltage in limb leads, S voltage in precordial leads, Sokolow and Cornell indexes, QRS axis deviation, and QRS notches in lateral and inferior leads) and mechanical dyssynchrony measured by tissue Doppler imaging (TDI). Results: A group of 50 patients were studied, 60% male, 78% with nonischemic cardiomyopathy, NYHA Class III–IV (86%), and ejection fraction of 0.22 ± 0.6. Intra‐ and interventricular dyssynchrony occurred in 68% and 74% of patients, respectively. The S amplitude in precordial leads and the Sokolow and Cornel indexes show a weak correlation with the degree of dyssynchrony. In the patients with QRS notching in the lateral and inferior leads, we observed significantly greater prevalence of intraventricular dyssynchrony, with sensitivity and specificity of 85% and 56%, respectively, for notches in lateral leads. The QRS duration presents moderate correlation with the degree of both intraventricular (r = 0.48) and interventricular dyssynchrony (r = 0.46). Conclusion: The following electrocardiographic parameters were related to the degree of mechanical dyssynchrony: QRS duration and notches in QRS. In addition, the patients tend to have highest S amplitude in precordial leads. Ann Noninvasive Electrocardiol 2011;16(1):41–48     

Tissue-Specific Inactivation of Type 2 Deiodinase Reveals Multilevel Control of Fatty Acid Oxidation by Thyroid Hormone in the Mouse

Type 2 deiodinase (D2) converts the prohormone thyroxine (T4) to the metabolically active molecule 3,5,3′-triiodothyronine (T3), but its global inactivation unexpectedly lowers the respiratory exchange rate (respiratory quotient [RQ]) and decreases food intake. Here we used FloxD2 mice to generate systemically euthyroid fat-specific (FAT), astrocyte-specific (ASTRO), or skeletal-muscle-specific (SKM) D2 knockout (D2KO) mice that were monitored continuously. The ASTRO-D2KO mice also exhibited lower diurnal RQ and greater contribution of fatty acid oxidation to energy expenditure, but no differences in food intake were observed. In contrast, the FAT-D2KO mouse exhibited sustained (24 h) increase in RQ values, increased food intake, tolerance to glucose, and sensitivity to insulin, all supporting greater contribution of carbohydrate oxidation to energy expenditure. Furthermore, FAT-D2KO animals that were kept on a high-fat diet for 8 weeks gained more body weight and fat, indicating impaired brown adipose tissue (BAT) thermogenesis and/or inability to oxidize the fat excess. Acclimatization of FAT-D2KO mice at thermoneutrality dissipated both features of this phenotype. Muscle D2 does not seem to play a significant metabolic role given that SKM-D2KO animals exhibited no phenotype. The present findings are unique in that they were obtained in systemically euthyroid animals, revealing that brain D2 plays a dominant albeit indirect role in fatty acid oxidation via its sympathetic control of BAT activity. D2-generated T3 in BAT accelerates fatty acid oxidation and protects against diet-induced obesity.     

Updates in biological therapies for knee injuries: menisci

The preservation of meniscal tissue is paramount for long-term joint function, especially in younger patients who are athletically active. Many studies have reported encouraging results following the repair of meniscus tears, including both simple longitudinal tears located in the periphery and complex multiplanar tears that extend into the central third avascular region. However, most types of meniscal lesions are managed with a partial meniscectomy. Options to restore the meniscus range from an allograft transplantation to the use of synthetic and biological technologies. Recent studies have demonstrated good long-term outcomes with meniscal allograft transplantation, although the indications and techniques continue to evolve, and the long-term chondroprotective potential of this approach has yet to be determined. Several synthetic implants, most of which are approved in the European market, have shown some promise for replacing part of or the entire meniscus, including collagen meniscal implants, hydrogels, and polymer scaffolds. Currently, there is no ideal implant generated by means of tissue engineering. However, meniscus tissue engineering is a fast developing field that promises to develop an implant that mimics the histologic and biomechanical properties of a native meniscus.     

Factors Associated with Prenatal Care and Seeking Assistance in Public Hospitals in Vitória,Espírito Santo,Brazil

Adequate prenatal care provides an opportunity for counseling and reducing the complications associated with pregnancy and delivery. Our objective was to describe the demographic, behavioral, and clinical profile of the pregnant women hospitalized at public maternity hospitals and to identify factors associated with six or more prenatal consultations in Vitória, Brazil. A cross-sectional study of 1,380 women was conducted in public maternity hospitals in Vitória, Brazil. Sixty-seven percent of participants had ≥6 prenatal consultations. Reasons for hospitalization were vaginal delivery (55.7%), cesarean section (32.9%), clinical treatment (7.7%), and abortion/miscarriage (3.7%). Having ≥9 years of schooling (odds ratio, OR = 1.8; 95% confidence interval, CI: 1.1–3.1), being married (OR = 1.9; 95% CI: 1.2–2.9) and delivering at term (OR = 3.6; 95% CI: 1.6–8.2) were significantly independently associated with having ≥6 prenatal consultations. Although higher education, being married, and delivering at term were associated with ≥6 prenatal consultations in this population, the high rate of Cesarean sections demonstrates the need for ongoing educative strategies among health professionals.     

Neutrophil Depletion and Chemokine Response after Liver Ischemia and Reperfusion

Hepatic surgery in mice is challenging because of the delicate nature of the liver, lack of intravenous access, and risk of hemorrhage. In order to study the ability of the liver to regenerate after surgical resection, we developed a novel, rapid, and safe technique for partial hepatectomy in mice. We determined the relative contributions of the seven lobes of the mouse liver and resected the three most anterior lobes for a 68% hepatectomy. We used general anesthesia, a small upper midline incision, silk suture to tie off the lobes to be resected, warming pads and lights, as well as subcutaneous saline injection to ensure minimal morbidity. We have performed a safe two-thirds hepatic resection in 288 of 300 C57BL6 mice (96%). Perioperative mortality was due to technical error. Minimal long-term morbidity was appreciated. This technique may be applied to any type of hepatic resection in mice. In addition, the general operative technique and perioperative management of these mice may be applied to all types of murine intra-abdominal procedures used for surgical research.