Effect of abrupt mitral regurgitation after balloon valvuloplasty on myocardial load and performance

AbstractThe concept that mitral regurgitation masks myocardial dysfunction by reducing afterload and augmenting ejection performance has not been well established in humans. The effect of abruptly produced mitral regurgitation on left ventricular loading and performance was therefore evaluated in five patients who developed this complication after an otherwise successful percutaneous balloon mitral valvuloplasty. Mitral valve area by Gorlin formula calculated with forward flow increased from 0.92 ± 0.14 to 2.75 ± 0.82 cm2. Mean left atrial pressure did not decrease (19 ± 4 to 19 ± 6 mm Hg). The size of the left atrial Vwave relative to mean left atrial pressure (peak V— mean left atrial pressure) increased from 7 ± 4 to 19 ± 6 mm Hg. Angiographic mitral regurgitation increased from 0+ or 1 + to >3+ in each patient and regurgitant fraction increased from 0.23 ± 0.11 to 0.55 ± 0.99 (p < 0.01).End-diastolic volume increased modestly from 148 ± 15 to 159 ± 15 ml (p = NS). Heart rate increased from 54 ± 5 to 71 ± 8 heats/min (p < 0.05), which may have prevented further increases in preload by shortening the filling period. End-systolic stress decreased by 32% from 277 ± 34 to 188 ± 52 kdyn/cm2(p < 0.01) as a result of a 25% decrease in end-systolic pressure from 121 ± 8 to 91 ± 7 mm Hg and a 16% decrease in end-systolic volume from 67 ± 13 to 56 ± 8 ml (p = NS). Contractility estimated from the preload-corrected ejection fraction-afterload relation decreased in one of the five patients and did not increase in the others despite an increase in heart rate, possibly as a result of myocardial depression from the balloon procedure itself. Nevertheless, the decrease in end-systolic volume could not be attributed to a net increase in contractility. The result of the changes in loading was an increase in ejection fraction from 0.55 ± 0.05 to 0.65 ± 0.04 (p < 0.05).Thus, abruptly produced mitral regurgitation increases ejection performance by reducing afterload without increasing contractility. This should be taken into consideration when anticipating the results of valve replacement for acute or subacute mitral regurgitation

Left ventricular apical puncture: A procedure surviving well into the new millennium

We report two patients with a history of prior mitral valve and aortic valve replacement with St. Jude prosthetic valves, who were referred for repeat valve replacement after noninvasive assessment was suggestive of prosthetic valve malfunction. Both patients were managed medically after evaluation with direct left ventricular apical puncture revealed normal hemodynamics in the first and mild aortic stenosis in the second patient. These two cases illustrate that, despite the advancements in the noninvasive evaluation of prosthetic heart valves, left ventricular direct puncture continues to have an important value in the evaluation of patients referred for repeat valve replacement, and it can prevent unnecessary surgeries associated with a high risk of morbidity and mortality. Cathet. Cardiovasc. Intervent. 49:68–73, 2000. © 2000 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35246/1/15_ftp.pd

El uso de Internet y las actitudes políticas: Datos cuantitativos y cualitativos de España

In this paper we argue that the widespread use of new technologies may contribute to a change in political attitudes in democracies in industrialized developed countries. The interactivity and cross-cutting nature of new technologies means they allow easier access to information. This can stimulate interest, encourage a sense of political effectiveness, and a preference for direct democracy. This hypothesis is evaluated using original qualitative and quantitative data collected in Spain. Data drawn from a study on the Internet and political participation are used in conjunction with data from a qualitative study of two focus groups comprising young middle-class citizens, segmented by their level of Internet use. We find Internet users to be clearly more interested in politics and to display higher levels of internal efficacy than nonusers, even after controlling for a variety of sociodemographic and attitudinal factors. The focus groups provided insights into the mechanisms underlying the differences detected between Internet users and nonusers.En este artículo sostenemos que la extensión del uso de las nuevas tecnologías puede contribuir a un cambio en las actitudes políticas en las democracias industrializadas desarrolladas. Las nuevas tecnologías permiten un acceso más fácil a la información y se caracterizan por la interactividad y la horizontalidad. Estos rasgos pueden fomentar el interés, la eficacia política y las preferencias para la democracia directa. Esta hipótesis se evalúa con datos cuantitativos y cualitativos originales recogidos en España. Se utilizan datos de un estudio sobre Internet y la participación política e información proveniente de dos grupos de discusión formados por jóvenes de clase media segmentados por el nivel de uso de Internet. Las personas usuarias de Internet están claramente más interesadas en la política y tienen un sentido de eficacia interna más desarrollado que las personas no usuarias de este nuevo medio, incluso después de controlar por una gran variedad de factores sociodemográficos y actitudinales. Los grupos de discusión aportaron elementos para comprender el significado de las diferencias actitudinales que se detectaron entre las personas usuarias de Internet y las no usuarias

Modifiable risk factors remain significant causes of medium term mortality after first time Coronary artery bypass grafting

<p>Abstract</p> <p>Background</p> <p>Whilst there is much current data on early outcomes after Coronary artery bypass grafting(CABG), there is relatively little data on medium term outcomes in the current era. The purpose of this study is to present a single surgeon series comprising of all first time CABG patients operated on with the technique of cross clamp fibrillation from Feb-1996 to through to Jan-2003, and to seek risk factors for medium term mortality in these patients.</p> <p>Methods</p> <p>Data was collected from Hospital Episode Statistics and departmental patient administration and tracking systems and cross checked using database techniques. Patient outcomes were searched using the National Health Service strategic tracing service.</p> <p>Results</p> <p>Mean follow up was 5.3 years(0–9.4 years) and was complete for all patients. 30-day survival was 98.4%, 1-year survival 95% and 8-year survival 79%. Cox-regression analysis revealed that several modifiable pre-operative risk factors remain significant predictors of medium term mortality, including Diabetes(Hazard Ratio(HR) 1.73, 95%CI 1.21–2.45), Chromic obstructive pulmonary disease(HR 2.02, 95%CI 1.09–3.72), Peripheral vascular disease(HR 1.68, 95%CI 1.13–2.5), Body mass index>30(HR 1.54, 95%CI 1.08–2.20) and current smoker at operation(HR 1.67, 95%CI 1.03–2.72). However hypertension(HR 1.31, 95%CI 0.95–1.82) and Hypercholestrolaemia(HR 0.81, 95%CI 0.58–1.13) were not predictive which may reflect adequate post-operative control.</p> <p>Conclusion</p> <p>Coronary artery bypass surgery using cross clamp fibrillation is associated with a very low operative mortality. Medium term survival is also good but risk factors such as smoking at operation, Chronic obstructive pulmonary disease, obesity and diabetes negatively impact this survival and should be aggressively treated in the years post-surgery.</p

The influence of institutional environment on venture capital development in emerging economies: the example of Nigeria

The aim of the study is to investigate the development of venture capital (VC) in an emerging economy lacking the fully-developed legal and financial institutions necessary to support private-equity financing. This study, undertaken in Nigeria, included extended interviews with venture capitalists (VCs), entrepreneurs who were able to secure VC funding and those who were not, a government minister and their key policy staff. The findings suggest that VCs require stable trusted institutional frameworks, regulations and tax regimes, alongside clear exit strategies. They also suggest that informal institution such as networking is important for VC development. These findings have major implications for VC policy and for the development of technology-based industrial start-ups. The paper contributes to the literature on the impact of institutions on VC development processes in emerging economies