Optimal Anti-ischemic Therapy: Newer Data from the HOPE, EUROPA and PEACE Trials

Several trials have proposed ACE-inhibitors as the foundation of anti-ischemic secondary preventive therapy for both short and long-term benefit in systolic heart failure, and an important anti-ischemic therapy in ischemic heart disease, diabetic and renal disease patients. The results of the HOPE trial indicated that ramipril, with “tissue” ACE-inhibition features, would benefit a broad range of patients for both primary and secondary prevention of both ischemic and vascular disease, and was beneficial in all subgroups of atherosclerotic coronary disease, cerebrovascular disease, peripheral vascular disease, or diabetes with one cardiovascular risk factor. Subsequently, the EUROPA trial complemented the findings of the HOPE trial in indicating the unique ability of tissue ACE-inhibition, this time with use of perindopril, in preventing cardiovascular events. On the other hand, the findings of a third trial (PEACE) using trandolapril did not confirm these favorable effects, albeit in a lower risk group of patients with ischemic heart disease. Nevertheless, combined analysis of the results of all three trials indicated that there seems to be a significant reduction of cardiovascular events in all patients with ischemic heart disease treated with an ACE inhibitor even in the absence of systolic left ventricular dysfunction or evidence of heart failure. These unique findings of these landmark trials are herein discussed

Cryptogenic Stroke and Migraine Headache: The Clinical Cardiologist's View

Cryptogenic stroke and migraine headache are disorders which most commonly affect persons younger than 55 years of age. In recent years these disorders have been found to have a strong association with inter-atrial cardiac defects, such as patent foramen ovale and atrial septal defect, and support the pathophysiological mechanism of paradoxical embolism with a right-to-left shunt. With the evolution of technology, magnetic resonance imaging has more clearly defined cryptogenic stroke, and percutaneous cardiac interventional devices have offered a simplified approach to closure of inter-atrial cardiac defects. Nevertheless, the evidence-based data of which sub-populations of patients with cryptogenic stroke or migraine headache will benefit from closure of inter-atrial cardiac defects is just being defined. This review offers a clinical cardiologist???s viewpoint of these developments

Cryptogenic Stroke and Migraine Headache: The Clinical Cardiologist???s View

Cryptogenic stroke and migraine headache are disorders which most commonly affect persons younger than 55 years of age. In recent years these disorders have been found to have a strong association with inter-atrial cardiac defects, such as patent foramen ovale and atrial septal defect, and support the pathophysiological mechanism of paradoxical embolism with a right-to-left shunt. With the evolution of technology, magnetic resonance imaging has more clearly defined cryptogenic stroke, and percutaneous cardiac interventional devices have offered a simplified approach to closure of inter-atrial cardiac defects. Nevertheless, the evidence-based data of which sub-populations of patients with cryptogenic stroke or migraine headache will benefit from closure of inter-atrial cardiac defects is just being defined. This review offers a clinical cardiologist’s viewpoint of these developments

Do insect outbreaks reduce the severity of subsequent forest fires?

Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate- and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect-fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. We first quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect-fire events (n = 81 spanning 1987-2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change

Effect of ventricular function on the exercise hemodynamics of variable rate pacing

AbstractTo determine the effect of ventricular function on the exercise hemodynamics of variable rate pacing, 16 selected patients underwent paired, double-blind, randomized exercise tests in single rate demand (VVI) or variable rate (VVIR) pacing modes. Ejection fraction and cardiac index were determined by two-dimensional and Doppler echocardiography at baseline and during peak exercise.Baseline ejection fraction ranged from 14 to 73% and was < 40% in 6 patients (Group 1) and ≥ 40% in 10 patients (Group 2). Duration of exercise was longer during the VVIR mode (502 s) than during the VVI mode (449 s) (p < 0.01) and unrelated to baseline ejection fraction. Heart rate during exercise increased 9% in the VVI mode and 35% in the VVIR mode (p < 0.005). Cardiac index increased 49% in the VVI mode and 83% in the VVIR mode. Analysis of variance for repeated measures showed a significant effect of pacing mode (p < 0.01) and exercise (p < 0.001), but not baseline ejection fraction, on cardiac index. Baseline ejection fraction did not correlate with the increase in cardiac index in either pacing mode or with the difference in increase between modes. There was no significant difference between Groups 1 and 2 in exercise duration, peak heart rate-blood pressure (rate-pressure) product, baseline or peak heart rate or baseline or peak cardiac index.Therefore, in selected patients, VVIR pacing during exercise results in an increase in heart rate, duration of exercise and cardiac index that is unrelated to the degree of baseline left ventricular dysfunction. These data have clinical implications for the use of variable rate pacemakers in patients with abnormalities of ventricular function

Do insect outbreaks reduce the severity of subsequent forest fires?

Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate-and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect-fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. Wefirst quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect-fire events (n = 81 spanning 1987-2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change.Keywords: fire ecology, remote sensing, regime change, forest health, defoliator, bark beetle, disturbance interaction

Cost Effectiveness of Sampling and Testing Programs

DTFH61-82-C-00015This report documents studies aimed at providing a means of establishing priorities among quality control tests and of optimizing sampling frequencies for each test, based on the effects of material properties measured on the performance of the pavements. Appropriate procedures were developed and are discussed in the report, including critical considerations and limitations due to lack of suitable stochastic models to predict performance and contractor response to changes in testing frequency. These procedures are embodied in computer program "COSTOP1", which was developed to assist state highway agencies in determining the optimum test frequency for a single test or the optimum test program for multiple tests to produce the greatest return for every dollar spent on testing. COSTOP1 is general and modular so that the testing programs for all paving construction and materials can be evaluated, and new models and differing repair strategies may be easily defined and input. Preliminary results based on limited models indicate that higher frequencies of testing than commonly used would be cost effective, decreasing the equivalent annual pavement costs by much more than the additional testing costs

Does wildfire likelihood increase following insect outbreaks in conifer forests?

Although there is acute concern that insect‐caused tree mortality increases the likelihood or severity of subsequent wildfire, previous studies have been mixed, with findings typically based on stand‐scale simulations or individual events. This study investigates landscape‐ and regional‐scale wildfire likelihood following outbreaks of the two most prevalent native insect pests in the US Pacific Northwest (PNW): mountain pine beetle (MPB; Dendroctonus ponderosae) and western spruce budworm (WSB; Choristoneura freemani). We leverage seamless census data across numerous insect and fire events to (1) summarize the interannual dynamics of insects (1970–2012) and wildfires (1984–2012) across forested ecoregions of the PNW; (2) identify potential linked disturbance interactions with an empirical wildfire likelihood index; (3) quantify this insect‐fire likelihood across different insect agents, time lags, ecoregions, and fire sizes. All three disturbance agents have occurred primarily in the drier, interior conifer forests east of the Cascade Range. In general, WSB extent exceeds MPB extent, which in turn exceeds wildfire extent, and each disturbance typically affects less than 2% annually of a given ecoregion. In recent decades across the PNW, wildfire likelihood does not consistently increase or decrease following insect outbreaks. There is evidence, however, of linked interactions that vary across insect agent (MPB, WSB), space (ecoregion), and time (interval since insect onset). Specifically, in most cases following MPB activity, fire likelihood is neither higher nor lower than in non‐MPB‐affected forests. In contrast, fire likelihood is lower following WSB activity across multiple ecoregions and time lags. In addition, insect‐fire likelihood is not consistently associated with interannual fire extent, suggesting that other factors (e.g., climate) control the disproportionately large fire years accounting for regional fire dynamics. Thus, although both bark beetles and defoliators alter fuels and associated fire potential, the windows of opportunity for increased or decreased fire likelihood are too narrow—or the phenomena themselves too rare—for a consistent signal to emerge across PNW conifer forests. These findings suggest that strategic plans should recognize (1) the relative rarity of insect‐fire interactions and (2) the potential ecosystem restoration benefits of native insect outbreaks, when they do occur

Does wildfire likelihood increase following insect outbreaks in conifer forests?

Although there is acute concern that insect-caused tree mortality increases the likelihood or severity of subsequent wildfire, previous studies have been mixed, with findings typically based on stand-scale simulations or individual events. This study investigates landscape- and regional-scale wildfire likelihood following outbreaks of the two most prevalent native insect pests in the US Pacific Northwest (PNW): mountain pine beetle (MPB; Dendroctonus ponderosae) and western spruce budworm (WSB; Choristoneura freemani). We leverage seamless census data across numerous insect and fire events to (1) summarize the interannual dynamics of insects (1970–2012) and wildfires (1984–2012) across forested ecoregions of the PNW; (2) identify potential linked disturbance interactions with an empirical wildfire likelihood index; (3) quantify this insect-fire likelihood across different insect agents, time lags, ecoregions, and fire sizes. All three disturbance agents have occurred primarily in the drier, interior conifer forests east of the Cascade Range. In general, WSB extent exceeds MPB extent, which in turn exceeds wildfire extent, and each disturbance typically affects less than 2% annually of a given ecoregion. In recent decades across the PNW, wildfire likelihood does not consistently increase or decrease following insect outbreaks. There is evidence, however, of linked interactions that vary across insect agent (MPB, WSB), space (ecoregion), and time (interval since insect onset). Specifically, in most cases following MPB activity, fire likelihood is neither higher nor lower than in non-MPB-affected forests. In contrast, fire likelihood is lower following WSB activity across multiple ecoregions and time lags. In addition, insect-fire likelihood is not consistently associated with interannual fire extent, suggesting that other factors (e.g., climate) control the disproportionately large fire years accounting for regional fire dynamics. Thus, although both bark beetles and defoliators alter fuels and associated fire potential, the windows of opportunity for increased or decreased fire likelihood are too narrow—or the phenomena themselves too rare—for a consistent signal to emerge across PNW conifer forests. These findings suggest that strategic plans should recognize (1) the relative rarity of insect-fire interactions and (2) the potential ecosystem restoration benefits of native insect outbreaks, when they do occur

Does wildfire likelihood increase following insect outbreaks in conifer forests?

Although there is acute concern that insect‐caused tree mortality increases the likelihood or severity of subsequent wildfire, previous studies have been mixed, with findings typically based on stand‐scale simulations or individual events. This study investigates landscape‐ and regional‐scale wildfire likelihood following outbreaks of the two most prevalent native insect pests in the US Pacific Northwest (PNW): mountain pine beetle (MPB; Dendroctonus ponderosae) and western spruce budworm (WSB; Choristoneura freemani). We leverage seamless census data across numerous insect and fire events to (1) summarize the interannual dynamics of insects (1970–2012) and wildfires (1984–2012) across forested ecoregions of the PNW; (2) identify potential linked disturbance interactions with an empirical wildfire likelihood index; (3) quantify this insect‐fire likelihood across different insect agents, time lags, ecoregions, and fire sizes. All three disturbance agents have occurred primarily in the drier, interior conifer forests east of the Cascade Range. In general, WSB extent exceeds MPB extent, which in turn exceeds wildfire extent, and each disturbance typically affects less than 2% annually of a given ecoregion. In recent decades across the PNW, wildfire likelihood does not consistently increase or decrease following insect outbreaks. There is evidence, however, of linked interactions that vary across insect agent (MPB, WSB), space (ecoregion), and time (interval since insect onset). Specifically, in most cases following MPB activity, fire likelihood is neither higher nor lower than in non‐MPB‐affected forests. In contrast, fire likelihood is lower following WSB activity across multiple ecoregions and time lags. In addition, insect‐fire likelihood is not consistently associated with interannual fire extent, suggesting that other factors (e.g., climate) control the disproportionately large fire years accounting for regional fire dynamics. Thus, although both bark beetles and defoliators alter fuels and associated fire potential, the windows of opportunity for increased or decreased fire likelihood are too narrow—or the phenomena themselves too rare—for a consistent signal to emerge across PNW conifer forests. These findings suggest that strategic plans should recognize (1) the relative rarity of insect‐fire interactions and (2) the potential ecosystem restoration benefits of native insect outbreaks, when they do occur