Induction and aggravation of atrioventricular valve regurgitation in the course of chronic right ventricular apical pacing

Aims Valvular regurgitation, especially on the right side of the heart, is a common finding even in patients without endocardial pacing leads. The severity of valvular regurgitation can change after permanent pacemaker (PPM) implantation. Ventricular pacing has been shown to cause ventricular dysfunction. The purpose of this study was to evaluate the mid-term effects of right ventricular (RV) apical pacing on atrioventricular (AV) valvular regurgitation in patients with a normal left ventricular function before PPM implantation. Methods and results Patients who required dual-chamber pacemakers due to a high-degree AV block were enrolled in the study. Initial echocardiography was performed before PPM implantation and re-evaluation by echocardiography was performed every 24 months thereafter. A total of 125 patients (61 male; mean age: 66.57 ± 6.45 years) were included in the study, and 115 pacemaker-dependent patients were followed up (mean ± SD; 4.08 ± 0.8 years). Echocardiography demonstrated mild tricuspid regurgitation (TR) and mitral regurgitation (MR) in 70 (60.1) and 34 (29.6) patients before PPM implantation, respectively. Moderate TR and MR were detected in 10 (8.7) and 1 (0.9) patients, respectively. Thirty-six (31.6) patients showed moderate-to-severe TR at long-term follow-up, compared with the 10 (8.7) patients, who had the same degree of TR before RV apical pacing (P< 0.001). Mild and moderate MR were detected in 54 (47) and 8 (7) patients after PPM implantation on the last echocardiography(P< 0.001). Baseline systolic pulmonary artery pressure (PAP) was 29.24 ± 8.45 mmHg, which increased to 36 ± 11 mmHg on the last echocardiography (P< 0.001). Conclusion Considering the haemodynamic effects at mid-term follow-up, left ventricular dysfunction is rare in patients with RV apical pacing and normal baseline left ventricular function. Right ventricular apical pacing is associated with a significant increase in the prevalence and severity of TR and MR. © The Author 2011

Erratum: Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning

Adaptation of Western Oak Seedlings to Yasuj Climate and Analysis of their Leaf Morphology

Analysis of performance and survival rate of different oak species in severe climate of Zagros forests especially under global warming can help with management, conservation and restoration of these species. So, seeds of three oak species of Zagros (Quercus branti, Q. infectoria and Q. libani) were collected from Baneh forests and sown in the common gardens of Yasuj. Then, their growth parameters such as collar diameter, height, trunk volume, height and collar increment, number of leaf and survival rate were measured and recorded during the growing season (June and October) for the first two years. Also, in order to find a relationship between these traits and leaf morphological and qualitative traits of seedlings, some parameters like leaf area, specific leaf area, number of sprout and branch, bending of seedlings were measured and recorded. Results showed that at early growth age, seedlings of Q. branti and Q. infectoria had the largest and smallest size, respectively. Also, Q. libani seedlings showed a lower survival rate in the second year than other studied species due to the larger seeds. Results of correlation showed that seedlings with larger leaf area, higher number of branch and less straightness had higher growth and survival rate. It can be concluded that Q. infectoria is more susceptive to the increasing period and intensity of drought than other oaks of Zagros species