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2.
Nature ; 629(8011): 370-375, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38600390

RESUMEN

Roads are expanding at the fastest pace in human history. This is the case especially in biodiversity-rich tropical nations, where roads can result in forest loss and fragmentation, wildfires, illicit land invasions and negative societal effects1-5. Many roads are being constructed illegally or informally and do not appear on any existing road map6-10; the toll of such 'ghost roads' on ecosystems is poorly understood. Here we use around 7,000 h of effort by trained volunteers to map ghost roads across the tropical Asia-Pacific region, sampling 1.42 million plots, each 1 km2 in area. Our intensive sampling revealed a total of 1.37 million km of roads in our plots-from 3.0 to 6.6 times more roads than were found in leading datasets of roads globally. Across our study area, road building almost always preceded local forest loss, and road density was by far the strongest correlate11 of deforestation out of 38 potential biophysical and socioeconomic covariates. The relationship between road density and forest loss was nonlinear, with deforestation peaking soon after roads penetrate a landscape and then declining as roads multiply and remaining accessible forests largely disappear. Notably, after controlling for lower road density inside protected areas, we found that protected areas had only modest additional effects on preventing forest loss, implying that their most vital conservation function is limiting roads and road-related environmental disruption. Collectively, our findings suggest that burgeoning, poorly studied ghost roads are among the gravest of all direct threats to tropical forests.


Asunto(s)
Automóviles , Conservación de los Recursos Naturales , Agricultura Forestal , Bosques , Árboles , Clima Tropical , Asia , Conservación de los Recursos Naturales/estadística & datos numéricos , Conservación de los Recursos Naturales/tendencias , Árboles/crecimiento & desarrollo , Conjuntos de Datos como Asunto , Agricultura Forestal/métodos , Agricultura Forestal/estadística & datos numéricos , Agricultura Forestal/tendencias
3.
J Chem Phys ; 160(7)2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38375903

RESUMEN

The N-H photodissociation dynamics of the pyridinyl radical upon continuous excitation to the optically bright, first excited ππ* electronic state by an ultra-violet (UV) laser pulse has been investigated within the mathematical framework of optimal control theory. The genetic algorithm (GA) is employed as the optimization protocol. We considered a three-state and three-mode model Hamiltonian, which includes the reaction coordinate, R (a1 symmetry); the coupling coordinates (namely, out-of-plane bending coordinate of the hydrogen atom of azine group), Θ (b1 symmetry); and the wagging mode, Q9 (a2 symmetry). The three electronic states are the ground, ππ*, and πσ* states. The πσ* state crosses both the ground state and the ππ* state, and it is a repulsive state on which N-H dissociation occurs upon photoexcitation. Different vibrational wave functions along the coupling coordinates, Θ and Q9, of the ground electronic state are used as the initial condition for solving the time-dependent Schrödinger equation. The optimal UV laser pulse is designed by applying the GA, which maximizes the dissociation yield. We obtained over 95% dissociation yield through the πσ* asymptote using the optimal pulse of a time duration of ∼30 000 a.u. (∼725.66 fs).

4.
ACS Omega ; 7(1): 1090-1099, 2022 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-35036772

RESUMEN

A series of different cores and nuclearity zinc metal clusters 1-5 have been synthesized using Zn(ClO4)2·6H2O, Schiff-base primary ligands, and dibenzoyl methane (DBM) or monoethanolamine (MEA) as co-ligand in a room-temperature reaction. The structure of the complexes is characterized using single-crystal X-ray diffraction. Among them, (1) [Zn(L1)(DBM)] is mononuclear; (2) [Zn4(L2)2(DBM)4], (3) [Zn4(L2)4(H2O)2(ClO4)2]·2CH2Cl2, and (4) [Zn4(L3)2(DBM)4] have a cubane core; and (5) [Zn4(L4)4(MEA)2(ClO4)2] has a ladderlike core structure. Compounds 1-5 have also been characterized using UV-vis absorption and emission spectroscopies. For an in-depth understanding of the absorption spectra of 1 and 3, density functional theory (DFT) calculations have been performed, which suggest that the transitions correspond to the π → π* intraligand charge transfer (ILCT) transitions.

5.
PLoS One ; 15(3): e0229614, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32126070

RESUMEN

The forests of Borneo-the third largest island on the planet-sustain some of the highest biodiversity and carbon storage in the world. The forests also provide vital ecosystem services and livelihood support for millions of people in the region, including many indigenous communities. The Pan-Borneo Highway and several hydroelectric dams are planned or already under construction in Sarawak, a Malaysian state comprising part of the Borneo. This development seeks to enhance economic growth and regional connectivity, support community access to services, and promote industrial development. However, the implications of the development of highway and dams for forest integrity, biodiversity and ecosystem services remained largely unreported. We assessed these development projects using fine-scale biophysical and environmental data and found several environmental and socioeconomic risks associated with the projects. The highway and hydroelectric dam projects will impact 32 protected areas including numerous key habitats of threatened species such as the proboscis monkey (Nasalis larvatus), Sarawak surili (Presbytis chrysomelas), Bornean orangutans (Pongo pygmaeus) and tufted ground squirrel (Rheithrosciurus macrotis). Under its slated development trajectory, the local and trans-national forest connectivity between Malaysian Borneo and Indonesian Borneo would also be substantially diminished. Nearly ~161 km of the Pan-Borneo Highway in Sarawak will traverse forested landscapes and ~55 km will traverse carbon-rich peatlands. The 13 hydroelectric dam projects will collectively impact ~1.7 million ha of forest in Sarawak. The consequences of planned highway and hydroelectric dams construction will increase the carbon footprint of development in the region. Moreover, many new road segments and hydroelectric dams would be built on steep slopes in high-rainfall zones and forested areas, increasing both construction and ongoing maintenance costs. The projects would also alter livelihood activities of downstream communities, risking their long-term sustainability. Overall, our findings identify major economic, social and environmental risks for several planned road segments in Sarawak-such as those between Telok Melano and Kuching; Sibu and Bintulu; and in the Lambir, Limbang and Lawas regions-and dam projects-such as Tutoh, Limbang, Lawas, Baram, Linau, Ulu Air and Baleh dams. Such projects need to be reviewed to ensure they reflect Borneo's unique environmental and forest ecosystem values, the aspirations of local communities and long-term sustainability of the projects rather than being assessed solely on their short-term economic returns.


Asunto(s)
Conservación de los Recursos Naturales/tendencias , Bosques , Desarrollo Sostenible/tendencias , Animales , Biodiversidad , Borneo , Secuestro de Carbono , Cambio Climático , Conservación de los Recursos Naturales/economía , Conservación de los Recursos Naturales/legislación & jurisprudencia , Desarrollo Económico , Ecosistema , Especies en Peligro de Extinción , Humanos , Indonesia , Malasia , Centrales Eléctricas/tendencias , Política Pública , Desarrollo Sostenible/economía , Desarrollo Sostenible/legislación & jurisprudencia
6.
PLoS One ; 14(9): e0221947, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31532810

RESUMEN

The Heart of Borneo initiative has promoted the integration of protected areas and sustainably-managed forests across Malaysia, Indonesia, and Brunei. Recently, however, member states of the Heart of Borneo have begun pursuing ambitious unilateral infrastructure-development schemes to accelerate economic growth, jeopardizing the underlying goal of trans-boundary integrated conservation. Focusing on Sabah, Malaysia, we highlight conflicts between its Pan-Borneo Highway scheme and the regional integration of protected areas, unprotected intact forests, and conservation-priority forests. Road developments in southern Sabah in particular would drastically reduce protected-area integration across the northern Heart of Borneo region. Such developments would separate two major clusters of protected areas that account for one-quarter of all protected areas within the Heart of Borneo complex. Sabah has proposed forest corridors and highway underpasses as means of retaining ecological connectivity in this context. Connectivity modelling identified numerous overlooked areas for connectivity rehabilitation among intact forest patches following planned road development. While such 'linear-conservation planning' might theoretically retain up to 85% of intact-forest connectivity and integrate half of the conservation-priority forests across Sabah, in reality it is very unlikely to achieve meaningful ecological integration. Moreover, such measure would be exceedingly costly if properly implemented-apparently beyond the operating budget of relevant Malaysian authorities. Unless critical road segments are cancelled, planned infrastructure will fragment important conservation landscapes with little recourse for mitigation. This likelihood reinforces earlier calls for the legal recognition of the Heart of Borneo region for conservation planning as well as for enhanced tri-lateral coordination of both conservation and development.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Borneo , Brunei , Desarrollo Económico , Ecosistema , Bosques , Indonesia , Malasia
7.
PLoS One ; 14(7): e0219408, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31339902

RESUMEN

The island of New Guinea hosts the third largest expanse of tropical rainforest on the planet. Papua New Guinea-comprising the eastern half of the island-plans to nearly double its national road network (from 8,700 to 15,000 km) over the next three years, to spur economic growth. We assessed these plans using fine-scale biophysical and environmental data. We identified numerous environmental and socioeconomic risks associated with these projects, including the dissection of 54 critical biodiversity habitats and diminished forest connectivity across large expanses of the island. Key habitats of globally endangered species including Goodfellow's tree-kangaroo (Dendrolagus goodfellowi), Matchie's tree kangaroo (D. matschiei), and several birds of paradise would also be bisected by roads and opened up to logging, hunting, and habitat conversion. Many planned roads would traverse rainforests and carbon-rich peatlands, contradicting Papua New Guinea's international commitments to promote low-carbon development and forest conservation for climate-change mitigation. Planned roads would also create new deforestation hotspots via rapid expansion of logging, mining, and oil-palm plantations. Our study suggests that several planned road segments in steep and high-rainfall terrain would be extremely expensive in terms of construction and maintenance costs. This would create unanticipated economic challenges and public debt. The net environmental, social, and economic risks of several planned projects-such as the Epo-Kikori link, Madang-Baiyer link, Wau-Malalaua link, and some other planned projects in the Western and East Sepik Provinces-could easily outstrip their overall benefits. Such projects should be reconsidered under broader environmental, economic, and social grounds, rather than short-term economic considerations.


Asunto(s)
Desarrollo Sostenible , Biodiversidad , Conservación de los Recursos Naturales , Bosques , Geografía , Papúa Nueva Guinea , Lluvia , Riesgo
8.
Sci Total Environ ; 663: 830-840, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-30738263

RESUMEN

The Sundarbans, in southern coastal Bangladesh, is the world's largest surviving mangrove habitat and the last stronghold of tiger adapted to living in a mangrove ecosystem. Using MaxEnt (maximum entropy modeling), current distribution data, land-use/land cover and bioclimatic variables, we modeled the likely future distribution of the globally endangered Bengal tiger (Panthera tigris tigris) in the Bangladesh Sundarbans. We used two climatic scenarios (i.e., RCP6.0 and RCP8.5) developed by the Intergovernmental Panel on Climate Change (IPCC) to provide projections of suitable habitats of Bengal tigers in 2050 and 2070. We also combined projected sea-level rise for the area in our models of future species distributions. Our results suggest that there will be a dramatic decline in suitable Bengal tiger habitats in the Bangladesh Sundarbans. Other than various aspects of local climate, sea-level rise is projected to have a substantial negative impact on Bengal tiger habitats in this low-lying area. Our model predicts that due to the combined effect of climate change and sea-level rise, there will be no suitable Bengal tiger habitat remaining in the Sundarbans by 2070. Enhancing terrestrial protected area coverage, regular monitoring, law enforcement, awareness-building among local residents among the key strategies needed to ensure long-term survival and conservation of the Bengal tiger in the Bangladesh Sundarbans.


Asunto(s)
Distribución Animal , Cambio Climático , Ecosistema , Especies en Peligro de Extinción , Tigres/fisiología , Animales , Bangladesh , Océanos y Mares , Movimientos del Agua , Humedales
9.
Sci Rep ; 9(1): 140, 2019 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-30644427

RESUMEN

Indonesian Borneo (Kalimantan) sustains ~37 million hectares of native tropical forest. Numerous large-scale infrastructure projects aimed at promoting land-development activities are planned or ongoing in the region. However, little is known of the potential impacts of this new infrastructure on Bornean forests or biodiversity. We found that planned and ongoing road and rail-line developments will have many detrimental ecological impacts, including fragmenting large expanses of intact forest. Assuming conservatively that new road and rail projects will influence only a 1 km buffer on either side, landscape connectivity across the region will decline sharply (from 89% to 55%) if all imminently planned projects proceed. This will have particularly large impacts on wide-ranging, rare species such as rhinoceros, orangutans, and elephants. Planned developments will impact 42 protected areas, undermining Indonesian efforts to achieve key targets under the Convention on Biological Diversity. New infrastructure will accelerate expansion in intact or frontier regions of legal and illegal logging and land colonization as well as illicit mining and wildlife poaching. The net environmental, social, financial, and economic risks of several imminent projects-such as parallel border roads in West, East, and North Kalimantan, new Trans-Kalimantan road developments in Central Kalimantan and North Kalimantan, and freeways and rail lines in East Kalimantan-could markedly outstrip their overall benefits. Such projects should be reconsidered in light of rigorous cost-benefit frameworks.


Asunto(s)
Ecosistema , Bosques , Planificación Social , Animales , Animales Salvajes , Biodiversidad , Borneo , Conservación de los Recursos Naturales , Especies en Peligro de Extinción , Indonesia
10.
Ecol Evol ; 8(8): 4237-4251, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29721294

RESUMEN

Closed-canopy forests are being rapidly fragmented across much of the tropical world. Determining the impacts of fragmentation on ecological processes enables better forest management and improves species-conservation outcomes. Lianas are an integral part of tropical forests but can have detrimental and potentially complex interactions with their host trees. These effects can include reduced tree growth and fecundity, elevated tree mortality, alterations in tree-species composition, degradation of forest succession, and a substantial decline in forest carbon storage. We examined the individual impacts of fragmentation and edge effects (0-100-m transect from edge to forest interior) on the liana community and liana-host tree interactions in rainforests of the Atherton Tableland in north Queensland, Australia. We compared the liana and tree community, the traits of liana-infested trees, and determinants of the rates of tree infestation within five forest fragments (23-58 ha in area) and five nearby intact-forest sites. Fragmented forests experienced considerable disturbance-induced degradation at their edges, resulting in a significant increase in liana abundance. This effect penetrated to significantly greater depths in forest fragments than in intact forests. The composition of the liana community in terms of climbing guilds was significantly different between fragmented and intact forests, likely because forest edges had more small-sized trees favoring particular liana guilds which preferentially use these for climbing trellises. Sites that had higher liana abundances also exhibited higher infestation rates of trees, as did sites with the largest lianas. However, large lianas were associated with low-disturbance forest sites. Our study shows that edge disturbance of forest fragments significantly altered the abundance and community composition of lianas and their ecological relationships with trees, with liana impacts on trees being elevated in fragments relative to intact forests. Consequently, effective control of lianas in forest fragments requires management practices which directly focus on minimizing forest edge disturbance.

11.
Curr Biol ; 28(11): R650-R651, 2018 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-29731303

RESUMEN

Nater et al.[1] recently identified a new orangutan species (Pongo tapanuliensis) in northern Sumatra, Indonesia - only the seventh described species of living great ape. The population of this critically-endangered species is perilously small, at only ∼800 individuals [1], ranking it among the planet's rarest animals. We assert that P. tapanuliensis is highly vulnerable to extinction because its remaining habitat is small, fragmented and poorly protected. While road incursions within its habitat are modest - road density is only one-eighth that of northern Sumatra - over one-fifth of its habitat is zoned for agricultural conversion or is composed of mosaic agricultural and regrowth/degraded forest. Additionally, a further 8% will be affected by flooding and infrastructure development for a hydroelectric project. We recommend urgent steps to increase the chance that P. tapanuliensis will persist in the wild.


Asunto(s)
Pongo pygmaeus , Pongo , Animales , Ecosistema , Genómica , Indonesia
12.
Curr Biol ; 27(20): R1130-R1140, 2017 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-29065299

RESUMEN

It is projected that 25 million km of new paved roads will be developed globally by 2050 - enough to encircle the planet more than 600 times. Roughly 90% of new roads will be built in developing nations, frequently in tropical and subtropical regions with high biodiversity and environmental values. Many developing nations are borrowing from international lenders or negotiating access to their natural resources in order to expand their transportation infrastructure. Given the unprecedented pace and extent of these initiatives, it is vital to thoroughly assess the potential consequences of large-scale road and highway projects. In appropriate contexts and locales, new roads can promote sizeable economic and social benefits. If poorly planned or implemented, however, new roads can provoke serious cost overruns, corruption and environmental impacts, while generating sparse economic benefits and intense social and political conflict. Using examples from developing nations, we identify risks that can hinder road projects in wet and dry tropical environments. Such risks, we assert, are often inadequately considered by project proponents, evaluators and the general public, creating a systematic tendency to overestimate project benefits while understating project risks. A more precautionary approach is needed to reduce risks while maximizing benefits of new road projects in the tropics.


Asunto(s)
Conservación de los Recursos Naturales/economía , Transportes/economía , Clima Tropical , Biodiversidad
13.
Sci Rep ; 7(1): 6071, 2017 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-28729670

RESUMEN

Human-induced forest fragmentation poses one of the largest threats to global diversity yet its impact on rattans (climbing palms) has remained virtually unexplored. Rattan is arguably the world's most valuable non-timber forest product though current levels of harvesting and land-use change place wild populations at risk. To assess rattan response to fragmentation exclusive of harvesting impacts we examined rattan abundance, demography and ecology within the forests of northeastern, Australia. We assessed the community abundance of rattans, and component adult (>3 m) and juvenile (≤3 m) abundance in five intact forests and five fragments (23-58 ha) to determine their response to a range of environmental and ecological parameters. Fragmented forests supported higher abundances of rattans than intact forests. Fragment size and edge degradation significantly increased adult rattan abundance, with more in smaller fragments and near edges. Our findings suggest that rattan increase within fragments is due to canopy disturbance of forest edges resulting in preferential, high-light habitat. However, adult and juvenile rattans may respond inconsistently to fragmentation. In managed forest fragments, a rattan abundance increase may provide economic benefits through sustainable harvesting practices. However, rattan increases in protected area forest fragments could negatively impact conservation outcomes.


Asunto(s)
Calamus , Bosques , Bosque Lluvioso , Clima Tropical , Conservación de los Recursos Naturales , Demografía , Ecosistema , Ambiente
14.
Sci Rep ; 6: 30012, 2016 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-27435389

RESUMEN

Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m(2) of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.


Asunto(s)
Biomasa , Carbono/análisis , Bosque Lluvioso , Australia , Conservación de los Recursos Naturales , Clima Tropical
15.
Sci Total Environ ; 566-567: 584-595, 2016 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-27236624

RESUMEN

As ecosystem services supply from tropical forests is declining due to deforestation and forest degradation, much effort is essential to sustain ecosystem services supply from tropical forested landscapes, because tropical forests provide the largest flow of multiple ecosystem services among the terrestrial ecosystems. In order to sustain multiple ecosystem services, understanding ecosystem services capacity across heterogeneous forest types and identifying certain ecosystem services that could be managed to leverage positive effects across the wider bundle of ecosystem services are required. We sampled three forest types, tropical rainforests, sclerophyll forests, and rehabilitated plantation forests, over an area of 32,000m(2) from Wet Tropics bioregion, Australia, aiming to compare supply and evaluate interactions and patterns of eight ecosystem services (global climate regulation, air quality regulation, erosion regulation, nutrient regulation, cyclone protection, habitat provision, energy provision, and timber provision). On average, multiple ecosystem services were highest in the rainforests, lowest in sclerophyll forests, and intermediate in rehabilitated plantation forests. However, a wide variation was apparent among the plots across the three forest types. Global climate regulation service had a synergistic impact on the supply of multiple ecosystem services, while nutrient regulation service was found to have a trade-off impact. Considering multiple ecosystem services, most of the rehabilitated plantation forest plots shared the same ordination space with rainforest plots in the ordination analysis, indicating that rehabilitated plantation forests may supply certain ecosystem services nearly equivalent to rainforests. Two synergy groups and one trade-off group were identified. Apart from conserving rainforests and sclerophyll forests, our findings suggest two additional integrated pathways to sustain the supply of multiple ecosystem services from a heterogeneous tropical forest landscape: (i) rehabilitation of degraded forests aiming to provide global climate regulation and habitat provision ecosystem services and (ii) management intervention to sustain global climate regulation and habitat provision ecosystem services.

16.
Circ Heart Fail ; 3(1): 35-43, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19850696

RESUMEN

BACKGROUND: The genesis of symptoms in patients with heart failure (HF) and normal ejection fraction (HFNEF) is unclear. Most investigations of HFNEF have focused on cardiac function at rest although most of these patients are breathless only on exercise. Stress-induced impairment in systolic or diastolic function could result in these symptoms. Method and Result- Forty-one patients with HFNEF and 29 controls underwent dobutamine stress echocardiography with color tissue Doppler imaging. Wall motion score index and regional myocardial systolic velocity (Sm) were measured at and peak stress. Systolic (Sa), early diastolic (Ea), and late diastolic (Aa) mitral annular velocities were averaged over the 6 periannular sites. Mitral annular long-axis velocity was lower in the HFNEF than controls at rest. Global, regional, and long-axis systolic function did not worsen with stress in the HFNEF group. The Ea decreased and the E/Ea increased with stress in the HFNEF but not in controls. The 6-minute walk distance was shorter and negatively correlated to the E/EA ratio at rest and stress in the HFNEF group. CONCLUSIONS: Impaired diastolic reserve results in stress-induced increase in the left ventricular end-diastolic pressure in patients with HFNEF giving rise to exercise intolerance.


Asunto(s)
Diástole , Tolerancia al Ejercicio , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/fisiopatología , Estudios de Casos y Controles , Ecocardiografía Doppler en Color , Ecocardiografía de Estrés , Femenino , Humanos , Masculino , Volumen Sistólico
17.
Eur J Heart Fail ; 10(4): 412-20, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18395672

RESUMEN

BACKGROUND: Cardiac resynchronisation therapy (CRT) improves symptoms and exercise capacity in many patients with heart failure (HF) who have left ventricular systolic dysfunction (LVSD) and markers of dyssynchrony. LV dyssynchrony is conventionally measured at rest but the symptoms of heart failure occur predominantly on exercise. Induction or exacerbation of dyssynchrony during stress might identify additional patients who could benefit from CRT. METHODS AND RESULTS: Seventy-seven patients (47 with QRSd<120 ms and 30 with QRSd>120 ms) with heart failure due to left ventricular systolic dysfunction and 22 normal subjects underwent dobutamine stress echocardiography using colour tissue Doppler imaging. Left intraventricular dyssynchrony was measured as the standard deviation of the time to peak velocity from the onset of the QRS (Ts-SD) and the difference between the maximum and minimum time to peak velocity (Tscor-diff) in the 12 non-apical segments at rest and during peak stress. Timings were corrected for heart rate. The mean values of these indices increased with stress in both groups of patients but not in control subjects (p<0.001). The prevalence of conventionally-defined dyssynchrony also increased with stress. CONCLUSION: In patients with heart failure, the severity and the prevalence of intraventricular dyssynchrony increase with stress. Whether stress-induced dyssynchrony will identify patients who might benefit from CRT awaits further research.


Asunto(s)
Ecocardiografía Doppler en Color , Ecocardiografía de Estrés , Insuficiencia Cardíaca/diagnóstico por imagen , Ventrículos Cardíacos/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador , Sístole/fisiología , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Estimulación Cardíaca Artificial , Dobutamina , Relación Dosis-Respuesta a Droga , Electrocardiografía , Femenino , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Humanos , Masculino , Persona de Mediana Edad , Volumen Sistólico/fisiología , Disfunción Ventricular Izquierda/fisiopatología , Disfunción Ventricular Izquierda/terapia , Función Ventricular Izquierda/fisiología
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