1680 Left ventricular filling pressure assessment with exercise stress echocardiography in patients with non-valvular atrial fibrillation

Background

Noninvasive parameters of LV filling pressure (E/e’) and pulmonary pressures (RVSP) by Doppler echocardiography correlate with functional capacity and outcome in sinus rhythm (SR). Their role in AF is less clear. Elevated left ventricular filling pressures (E/e’) and pulmonary artery systolic pressures (PASP) by Doppler stress echocardiography correlate with impaired functional capacity in patients in sinus rhythm (SR). However, there is limited data in atrial fibrillation (AF).

Purpose

The aim of this study was to delineate the characteristics of patients with AF referred for exercise stress echocardiography and determine the prevalence and significance of E/e’ and PASP elevations in AF.

Methods

Subjects were patients referred for exercise treadmill stress echocardiography (n= 14,937) and underwent regional wall motion assessment, Doppler assessment of mitral inflow (E) and early tissue relaxation (e’) velocities and PASP at rest and immediately following maximum symptom limited exercise. Exclusion criteria included significant valvular heart disease (moderate or greater stenosis and/or regurgitation of any cardiac valve or previous valve repair or replacement) (1%), congenital heart disease (<1%) or refusal to participate in research (<1%).

Results

Patients with AF (n = 310, 2%) were older (71 ± 10 vs 59 ± 13 years, p < 0.001). While resting blood pressure was similar, resting heart rates were higher in AF (80 ± 17 bpm vs 73 ± 13 bpm, p < 0.0001). AF patients achieved lower workloads (6.4 ± 2.4 METS vs 9 ± 2.4 METS, p < 0.001) with lower peak double products (22336 ± 6677 vs 25148 ± 5438, p < 0.001). Rates of resting (27% vs 10%, p < 0.0001) and exercise-induced (37% vs 20%, p < 0.0001) regional wall motion abnormalities were higher in AF. Mean E/e’ was higher in AF at rest (12 ± 5 vs 9 ± 3, p < 0.001) and with exercise (12 ± 5 vs 10 ± 4, p < 0.001), with a higher percentage of patients in AF having E/e’ ≥15 at rest (20% vs 6% in SR, p= <0.001) and with exercise in (23% vs 8%, p < 0.001). PASP was higher in AF at rest (33 ± 8 mm Hg vs 28 ± 6 mm Hg, p < 0.001) and with exercise (48 ± 12 vs 42 ± 11, p < 0.001) compared to SR. E/e’ correlated with exercise capacity in AF and in SR, with an E/e’ cutoff of 11.7 that was best predictive of impaired functional capacity (< 5 METS in women and < 7 METS in men).

Conclusions

Abnormalities of E/e’ and PASP are more prevalent in patients with AF and correlate with impaired functional capacity. In patients with AF, a medial E/e’ ratio of ≥ 12 immediately following exercise is best associated with impaired functional capacity.

Antimicrobial and biocompatible properties of nanomaterials

The rapid development of drug-resistant characteristics in pathogenic viral, bacterial, and fungal species and the consequent spread of infectious diseases are currently receiving serious attention. Indeed, there is a pressing demand to explore novel materials and develop new strategies that can address these issues of serious concern. Nanomaterials are currently proving to be the most capable therapeutic agents to cope with such hazards. The exceptional physiochemical properties and impressive antimicrobial capabilities of nanoparticles have provoked their utilization in biomedical fields. Nanomaterials of both organic and inorganic nature have shown the capabilities of disrupting microbial cells through different mechanisms. Along with the direct influence on the microbial cell membrane, DNA and proteins, these nanomaterials produce reactive oxygen species (ROS) that damage cell components and viruses. Currently, a serious hazard associated with these antimicrobial nanomaterials is their toxicity to human and animal cells. Extensive studies have reported the dose, time, and cell-dependent toxicology of various nanomaterials, and some have shown excellent biocompatible properties. Nevertheless, there is still debate regarding the use of nanomaterials for medical applications. Therefore, in this review, the antimicrobial activities of various nanomaterials with details of their acting mechanisms were compiled. The relative toxic and biocompatible behavior of nanomaterials emphasized in this study provides information pertaining to their practical applicability in medical fields.

Serum zinc level in preterm low birth weight babies and its comparison between preterm AGA and preterm SGA babies

Low birth weight (LBW) is a major child health problem in Bangladesh and continuing to great threat to child health and child survival in Bangladesh. LBW is a silent emergency but crisis is real and its persistence has profound and frightening impact on neonatal mortality. This observational study was conducted in Dhaka Shishu Hospital, Dhaka, Bangladesh during July 2004 to June 2005. Serum zinc levels were estimated between two groups: group-I preterm AGA (n=50), group II preterm SGA (n=50) babies. Blood samples were collected from the study population in neonatal unit and serum zinc levels were measured by flame atomic absorption spectrophotometry in Atomic Energy Center, Dhaka, Bangladesh. Observed data were made comparison among groups by Students 't' test. It was observed serum zinc level (60.2+/-15.2) in group I and (62.1+/-12.4) in group II. Serum zinc level was in lower limit of normal range in both groups with more lower level in preterm AGA babies but their difference was not statistically significant (p>0.05). So zinc supplementation may enhance the growth of preterm LBW babies in their early months of lives.