Comparison of right atrial pacing soon after myocardial infarction with treadmill testing 6 months later

Seventy-four patients recovering from acute myocardial infarction underwent right atrial pacing before hospital discharge, and treadmill exercise testing 6 months later. The early right atrial pacing test was positive in 32 patients (43 percent) and the late treadmill test was positive in 32 patients (42 percent). The results of the two tests were concordant in 77 percent of the patients, 23 with an ischemic response and 34 with a normal response on both tests. In nine patients a positive right atrial pacing test was followed by a negative treadmill test, and in eight patients a negative pacing test was followed by a positive treadmill test. A positive right atrial pacing test at hospital discharge had an 81.0 percent predictive accuracy for a positive late treadmill test; chest pain, congestive heart failure or increased cardiothoracic ratio at discharge had a predictive value of only 52.9, 42.8 and 42.8 percent, respectively. Both the early right atrial pacing test and the late treadmill test were positive in a significantly higher proportion of patients with inferior or subendocardial infarction than of patients with anterior myocardial infarction. During early right atrial pacing the mean maximal heart rate achieved was higher than that during late treadmill testing (148 versus 133 beats/min) and the mean systolic blood pressure was lower (137 versus 162 mm Hg), but the pressure-rate product was similar on the two tests (20,282 versus 21,455 mm Hg/min). This finding may explain the similar frequency of ischemic responses to the two tests. These results indicate that the response to right atrial pacing soon after myocardial infarction is a good predictor for the presence or absence of an ischemic response to treadmill testing 6 months later. Thus, early right atrial pacing at the time of hospital discharge may be used to determine the pace of rehabilitation and short-term prognosis.     

Dynamic mitral regurgitation. An important determinant of the hemodynamic response to load alterations and inotropic therapy in severe heart failure

Cardiac performance and mitral regurgitation were measured by Doppler echocardiography and right heart catheterization in 12 patients with severe congestive heart failure who performed isometric exercise during control and intravenous administration of dobutamine and nitroglycerin. During control isometric exercise, mitral regurgitant volume increased from 18 +/- 13 to 31 +/- 17 ml (p less than 0.01), while forward stroke volume, by both thermodilution and Doppler echocardiography, substantially decreased. At rest, dobutamine decreased mitral regurgitant volume from 18 +/- 13 to 11 +/- 10 ml (p less than 0.05), while forward stroke volume increased from 46 +/- 13 to 55 +/- 15 ml (p less than 0.05). During isometric exercise, dobutamine tended to decrease mitral regurgitant volume (24 +/- 12 vs. 31 +/- 17 ml; NS) when compared with control exercise. At rest, nitroglycerin decreased mitral regurgitant volume from 18 +/- 13 to 11 +/- 11 ml (p less than 0.05), while forward stroke volume, by both thermodilution and Doppler echocardiography, substantially increased. Similarly, during isometric exercise, nitroglycerin decreased mitral regurgitant volume from 31 +/- 17 to 20 +/- 14 ml (p less than 0.05), while significantly increasing forward stroke volume. At control rest, the median mitral regurgitant fraction was 24% for the 12 patients. Neither dobutamine nor nitroglycerin changed significantly forward stroke and mitral regurgitant volumes at rest and during isometric exercise in the six patients with resting mitral regurgitant fraction below the median. In contrast, dobutamine and nitroglycerin significantly decreased mitral regurgitant volume and increased forward stroke volume both at rest and during isometric exercise in the six patients with mitral regurgitant fraction greater than the median.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modulating lexical and semantic processing by transcranial direct current stimulation

Here we aim to evaluate the ability of transcranial direct current stimulation (tDCS), which is applied over Wernicke’s area and its right homologue, to influence lexical decisions and semantic priming and establish an involvement for temporo-parietal areas in lexical and semantic processing. Thirty-two subjects (17 women) completed a lexical decision task and a semantic priming task while receiving 20 min of bilateral tDCS stimulation (right anodal/left cathodal or left anodal/right cathodal stimulation) or sham stimulation. We hypothesized that right anodal/left cathodal stimulation over temporo-parietal areas would selectively interrupt the typical lexical processing dominance of the left hemisphere and facilitate mediated priming, while left anodal/right cathodal stimulation would selectively facilitate lexical processing and direct priming. Results showed impaired lexical processing under right anodal/left cathodal stimulation in comparison with sham and left anodal/right cathodal stimulation. Results are discussed in light of previous findings and hemispheric lateralization models.     

Critical care trainees’ career goals and needs: A Canadian survey

Designing an effective training program requires information regarding the needs, capability and aspirations of its users. Prompted by the low career satisfaction levels shown by critical care medicine (CCM) clinicians in a previous survey, and a lack of data regarding the career goals of CCM trainees in Canadian training programs, this survey-based study, which had an exemplary response rate of 85%, examined career expectations, and the barriers and enablers to career goals among individuals from adult and pediatric CCM programs across Canada.

BACKGROUND:

For training programs to meet the needs of trainees, an understanding of their career goals and expectations is required.

OBJECTIVES:

Canadian critical care medicine (CCM) trainees were surveyed to understand their career goals in terms of clinical work, research, teaching, administration and management; and to identify their perceptions regarding the support they need to achieve their goals.

METHODS:

The online survey was sent to all trainees registered in a Canadian adult or pediatric CCM program. It documented the participants’ demographics; their career expectations; the perceived barriers and enablers to achieve their career goals; and their perceptions relating to their chances of developing a career in different areas.

RESULTS:

A response rate of 85% (66 of 78) was obtained. The majority expected to work in an academic centre. Only approximately one-third (31%) estimated their chances of obtaining a position in CCM as >75%. The majority planned to devote 25% to 75% of their time performing clinical work and <25% in education, research or administration. The trainees perceived that there were limited employment opportunities. Networking and having specialized expertise were mentioned as being facilitators for obtaining employment. They expressed a need for more protected time, resources and mentorship for nonclinical tasks during training.

CONCLUSION:

CCM trainees perceived having only limited support to help them to achieve their career goals and anticipate difficulties in obtaining successful employment. They identified several gaps that could be addressed by training programs, including more mentoring in the areas of research, education and administration.     

Establishing a multidisciplinary diabetic foot team in a large tertiary hospital: a workshop

Every year, over 1 million people with diabetes lose a leg due to diabetic foot disease. Most amputations are preceded by a foot ulcer. Causes for the development of foot ulcers are generally multifactorial and may include neuropathy, peripheral vasculopathy, abnormal foot mechanics and infection. Multidisciplinary approach to the patient with acute diabetic foot is mandatory and has been shown to reduce amputation rate. In our article we describe the establishment of a multidisciplinary diabetic foot team in a large tertiary hospital and its outcomes. Copyright © 2014 John Wiley & Sons, Ltd.     

Cytocompatibility of novel extracellular matrix protein analogs of biodegradable polyester polymers derived from α-hydroxy amino acids

One of the challenges in regenerative medicine is the development of novel biodegradable materials to build scaffolds that will support multiple cell types for tissue engineering. Here we describe the preparation, characterization, and cytocompatibility of homo- and hetero-polyesters of α-hydroxy amino acid derivatives with or without lactic acid conjugation. The polymers were prepared by a direct condensation method and characterized using gel permeation chromatography, ¹H-nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, optical activity, and solubility. The surface charge of the polymers was evaluated using zeta potential measurements. The polymers were coated onto glass cover slips followed by characterization using nano-surface profiler, thin film reflectometry, and atomic force microscopy (AFM). Their interaction with endothelial and neuronal cells was assessed using adhesion, proliferation, and differentiation assays. Of the characterized polymers, Poly-HOVal-LA, but not Poly-(D)HOPhe, significantly augmented nerve growth factor (NGF)-induced neuronal differentiation of the PC12 pheochromcytoma cells. In contrast, Poly-HOLeu increased by 20% the adhesion of endothelial cells, but did not affect PC12 cell differentiation. NGF-induced Erk1/2 phosphorylation in PC12 cells grown on the different polymers was similar to the effect observed for cells cultured on collagen type I. While no significant association could be established between charge and the differentiative/proliferative properties of the polymers, AFM analysis indicated augmentation of NGF-induced neuronal differentiation on smooth polymer surfaces. We conclude that overall selective cytocompatibility and bioactivity might render α-hydroxy amino acid polymers useful as extracellular matrix-mimicking materials for tissue engineering.