577 research outputs found
The use of remote monitoring of cardiac implantable devices during the COVID-19 pandemic: an EHRA physician survey
It is unclear to what extent the COVID-19 pandemic has influenced the use of remote monitoring (RM) of cardiac implantable electronic devices (CIEDs). The present physician-based European Heart Rhythm Association (EHRA) survey aimed to assess the influence of the COVID-19 pandemic on RM of CIEDs among EHRA members and how it changed the current practice. The survey comprised 27 questions focusing on RM use before and during the pandemic. Questions focused on the impact of COVID-19 on the frequency of in-office visits, data filtering, reasons for initiating in-person visits, underutilization of RM during COVID-19, and RM reimbursement. A total of 160 participants from 28 countries completed the survey. Compared to the pre-pandemic period, there was a significant increase in the use of RM in patients with pacemakers (PMs) and implantable loop recorders (ILRs) during the COVID-19 pandemic (PM 24.2 vs. 39.9%, P = 0.002; ILRs 61.5 vs. 73.5%, P = 0.028), while there was a trend towards higher utilization of RM for cardiac resynchronization therapy-pacemaker (CRT-P) devices during the pandemic (44.5 vs. 55%, P = 0.063). The use of RM with implantable cardioverter-defibrillators (ICDs) and CRT-defibrillator (CRT-D) did not significantly change during the pandemic (ICD 65.2 vs. 69.6%, P = 0.408; CRT-D 65.2 vs. 68.8%, P = 0.513). The frequency of in-office visits was significantly lower during the pandemic (P < 0.001). Nearly two-thirds of participants (57 out of 87 respondents), established new RM connections for CIEDs implanted before the pandemic with 33.3% (n = 29) delivering RM transmitters to the patient's home address, and the remaining 32.1% (n = 28) activating RM connections during an in-office visit. The results of this survey suggest that the crisis caused by COVID-19 has led to a significant increase in the use of RM of CIEDs
Systemic, pulmonary and coronary haemodynamic actions of the novel dopamine receptor agonist in awake pigs at rest and during treadmill exercise Z1046
1. In view of the potential therapeutic application of specific dopamine receptor agonists in the treatment of hypertension and left ventricular dysfunction, we investigated the cardiovascular actions of the novel mixed D1/D2 dopamine receptor agonist Z1046 in awake pigs at rest and during treadmill exercise. 2. Thirteen swine were chronically instrumented under sterile conditions for measurement of systemic, pulmonary, and coronary haemodynamics. Regional blood flows were determined with the radioactive microsphere technique. 3. Z1046 (1, 10, 100 μg kg-1, i.v.) produced dose-dependent reductions in central aortic blood pressure (up to 27 ± 3%, P ≤ 0.05) in awake resting pigs which was accompanied by only minimal reflex activation of the sympathetic nervous system. The hypotensive response was principally the result of peripheral vasodilatation (system vascular resistance decreased up to 35 ± 4%, P ≤ 0.05), which was located in the cerebral, coronary, renal, mesenteric, adrenal, splenic and skeletal muscular vascular beds (vascular resistance decreased up to 30-40% after the highest dose in these beds). Only in the cerebral and mesenteric bed was the vasodilatation sufficiently large to overcome the decrease in blood pressure and result in an increased blood flow; the vasodilatation in the coronary bed was most likely due to autoregulation as neither coronary blood flow nor myocardial oxygen demand were changed significantly by Z1046. The systemic vasodilatation that was caused by the highest i.v. dose (100 μg kg-1) was accompanied by transient and minor increases in heart rate (15 ± 5%, P ≤ 0.05) and cardiac output (15 ± 5%, P ≤ 0.05) whereas after 10 μg kg-1, i.v., a slight decrease in cardiac output also contributed to the hypotension. Z1046 had no effect on pulmonary vascular resistance. 4. The systemic vasodilator responses to Z1046 (100 μg kg-1, i.v.) were sustained during treadmill exercise (2-4 km h-1 which produced heart rates of up to 233 ± 10 beats min-1), but with increasing treadmill speed attenuation of the exercise-induced increase in heart rate (-11 ± 3%, P ≤ 0.05) and hence cardiac output (-10 ± 3%, P ≤ 0.05) (as stroke volume was not altered by Z1046) contributed significantly to a lower aortic blood pressure (-20 ± 3%, P ≤ 0.05). Z1046 had no effect on pulmonary vascular resistance during exercise. 5. Oral administration of Z1046 (0.5, 1.5 mg kg-1) produced a fall in central aortic blood pressure (up to 15 ± 3%, P ≤ 0.05), which developed gradually during the first 90 min and lasted up to 4 h after administration, again with negligible changes in heart rate and LVdP/dt(max). 6. Neither non-selective α- and β-adrenoceptor blockade, nor selective α2-adrenoceptor blockade altered the vasodilator actions of Z1046, but non-selective α- and β-adrenoceptor blockade abolished the cardiac responses to dopamine receptor stimulation, suggesting that its cardiac actions were principally caused by D2-receptor-mediated inhibition of catecholamine release, whereas the vasodilator response was probably the result of vascular D1-receptor stimulation. 7. In conclusion, the novel dopamine receptor agonist Z1046 is an effective blood pressure lowering agent that elicits minimal reflex activation of the sympathetic nervous system in awake resting pigs. Systemic vasodilatation was not affected by combined α- and β-adrenoceptor blockade, which is consistent with a predominantly D1 receptor-dependent vasodilator mechanism. The hypotensive effect is maintained during treadmill exercise during which systemic vasodilatation and a lower cardiac output both contribute to the blood pressure lowering actions of Z1046. The cardiovascular profile of this orally active compound warrants further investigation of this class of drugs in experimental and clinical hypertension.</p
Systemic, pulmonary and coronary haemodynamic actions of the novel dopamine receptor agonist in awake pigs at rest and during treadmill exercise Z1046
1. In view of the potential therapeutic application of specific dopamine receptor agonists in the treatment of hypertension and left ventricular dysfunction, we investigated the cardiovascular actions of the novel mixed D1/D2 dopamine receptor agonist Z1046 in awake pigs at rest and during treadmill exercise. 2. Thirteen swine were chronically instrumented under sterile conditions for measurement of systemic, pulmonary, and coronary haemodynamics. Regional blood flows were determined with the radioactive microsphere technique. 3. Z1046 (1, 10, 100 μg kg-1, i.v.) produced dose-dependent reductions in central aortic blood pressure (up to 27 ± 3%, P ≤ 0.05) in awake resting pigs which was accompanied by only minimal reflex activation of the sympathetic nervous system. The hypotensive response was principally the result of peripheral vasodilatation (system vascular resistance decreased up to 35 ± 4%, P ≤ 0.05), which was located in the cerebral, coronary, renal, mesenteric, adrenal, splenic and skeletal muscular vascular beds (vascular resistance decreased up to 30-40% after the highest dose in these beds). Only in the cerebral and mesenteric bed was the vasodilatation sufficiently large to overcome the decrease in blood pressure and result in an increased blood flow; the vasodilatation in the coronary bed was most likely due to autoregulation as neither coronary blood flow nor myocardial oxygen demand were changed significantly by Z1046. The systemic vasodilatation that was caused by the highest i.v. dose (100 μg kg-1) was accompanied by transient and minor increases in heart rate (15 ± 5%, P ≤ 0.05) and cardiac output (15 ± 5%, P ≤ 0.05) whereas after 10 μg kg-1, i.v., a slight decrease in cardiac output also contributed to the hypotension. Z1046 had no effect on pulmonary vascular resistance. 4. The systemic vasodilator responses to Z1046 (100 μg kg-1, i.v.) were sustained during treadmill exercise (2-4 km h-1 which produced heart rates of up to 233 ± 10 beats min-1), but with increasing treadmill speed attenuation of the exercise-induced increase in heart rate (-11 ± 3%, P ≤ 0.05) and hence cardiac output (-10 ± 3%, P ≤ 0.05) (as stroke volume was not altered by Z1046) contributed significantly to a lower aortic blood pressure (-20 ± 3%, P ≤ 0.05). Z1046 had no effect on pulmonary vascular resistance during exercise. 5. Oral administration of Z1046 (0.5, 1.5 mg kg-1) produced a fall in central aortic blood pressure (up to 15 ± 3%, P ≤ 0.05), which developed gradually during the first 90 min and lasted up to 4 h after administration, again with negligible changes in heart rate and LVdP/dt(max). 6. Neither non-selective α- and β-adrenoceptor blockade, nor selective α2-adrenoceptor blockade altered the vasodilator actions of Z1046, but non-selective α- and β-adrenoceptor blockade abolished the cardiac responses to dopamine receptor stimulation, suggesting that its cardiac actions were principally caused by D2-receptor-mediated inhibition of catecholamine release, whereas the vasodilator response was probably the result of vascular D1-receptor stimulation. 7. In conclusion, the novel dopamine receptor agonist Z1046 is an effective blood pressure lowering agent that elicits minimal reflex activation of the sympathetic nervous system in awake resting pigs. Systemic vasodilatation was not affected by combined α- and β-adrenoceptor blockade, which is consistent with a predominantly D1 receptor-dependent vasodilator mechanism. The hypotensive effect is maintained during treadmill exercise during which systemic vasodilatation and a lower cardiac output both contribute to the blood pressure lowering actions of Z1046. The cardiovascular profile of this orally active compound warrants further investigation of this class of drugs in experimental and clinical hypertension.</p
Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations
This study presents a historical review, a meta-analysis, and recommendations for users about weight–length relationships, condition factors and relative weight equations. The historical review traces the developments of the respective concepts. The meta-analysis explores 3929 weight–length relationships of the type W = aLb for 1773 species of fishes. It shows that 82% of the variance in a plot of log a over b can be explained by allometric versus isometric growth patterns and by different body shapes of the respective species. Across species median b = 3.03 is significantly larger than 3.0, thus indicating a tendency towards slightly positive-allometric growth (increase in relative body thickness or plumpness) in most fishes. The expected range of 2.5 < b < 3.5 is confirmed. Mean estimates of b outside this range are often based on only one or two weight–length relationships per species. However, true cases of strong allometric growth do exist and three examples are given. Within species, a plot of log a vs b can be used to detect outliers in weight–length relationships. An equation to calculate mean condition factors from weight–length relationships is given as Kmean = 100aLb−3. Relative weight Wrm = 100W/(amLbm) can be used for comparing the condition of individuals across populations, where am is the geometric mean of a and bm is the mean of b across all available weight–length relationships for a given species. Twelve recommendations for proper use and presentation of weight–length relationships, condition factors and relative weight are given
Classification of forest management approaches: a new conceptual framework and its applicability to European forestry
The choice between different forest management practices is a crucial step in short, medium, and long-term decision making in forestry and when setting up measures to support a regional or national forest policy. Some conditions such as biogeographically determined site factors, exposure to major disturbances, and societal demands are predetermined, whereas operational processes such as species selection, site preparation, planting, tending, or thinning can be altered by management. In principle, the concept of a forest management approach provides a framework for decision making, including a range of silvicultural operations that influence the development of a stand or group of trees over time. These operations vary among silvicultural systems and can be formulated as a set of basic principles. Consequently, forest management approaches are essentially defined by coherent sets of forest operation processes at a stand level. Five ideal forest management approaches (FMAs) representing a gradient of management intensity are described using specific sets of basic principles that enable comparison across European forests. Each approach is illustrated by a regional European case study. The observed regional variations resulting from changing species composition, stand density, age structure, stand edges, and site conditions can be interpreted using the FMA framework. Despite being arranged along an intensity gradient, the forest management approaches are not considered to be mutually exclusive, as the range of options allows for greater freedom in selecting potential silvicultural operations. As derived goods and services are clearly affected, the five forest management approaches have implications for sustainability. Thus, management objectives can influence the balance between the economic, ecological, and social dimensions of sustainability. The utility of this framework is further demonstrated through the different contributions to this special issue
A direct comparison of natural and acoustic-radiation-force-induced cardiac mechanical waves
Natural and active shear wave elastography (SWE) are potential ultrasound-based techniques to non-invasively assess myocardial stiffness, which could improve current diagnosis of heart failure. This study aims to bridge the knowledge gap between both techniques and discuss their respective impacts on cardiac stiffness evaluation. We recorded the mechanical waves occurring after aortic and mitral valve closure (AVC, MVC) and those induced by acoustic radiation force throughout the cardiac cycle in four pigs after sternotomy. Natural SWE showed a higher feasibility than active SWE, which is an advantage for clinical application. Median propagation speeds of 2.5–4.0 m/s and 1.6–4.0 m/s were obtained after AVC and MVC, whereas ARF-based median speeds of 0.9–1.2 m/s and 2.1–3.8 m/s were reported for diastole and systole, respectively. The different wave characteristics in both methods, such as the frequency content, complicate the direct comparison of waves. Nevertheless, a good match was found in propagation speeds between natural and active SWE at the moment of valve closure, and the natural waves showed higher propagation speeds than in diastole. Furthermore, the results demonstrated that the natural waves occur in between diastole and systole identified with active SWE, and thus represent a myocardial stiffness in between relaxation and contraction
Dichotomy between the transcriptomic landscape of naturally versus accelerated aged murine hearts
We investigated the transcriptomic landscape of the murine myocardium along the course of natural aging and in three distinct mouse models of premature aging with established aging-related cardiac dysfunction. Genome-wide total RNA-seq was performed and the expression patterns of protein-coding genes and non-coding RNAs were compared between hearts from naturally aging mice, mice with cardiac-specific deficiency of a component of the DNA repair machinery, mice with reduced mitochondrial antioxidant capacity and mice with reduced telomere length. Our results demonstrate that no dramatic changes are evident in the transcriptomes of naturally senescent murine hearts until two years of age, in contrast to the transcriptome of accelerated aged mice. Additionally, these mice displayed model-specific alterations of the expression levels of protein-coding and non-coding genes with hardly any overlap with age-related signatures. Our data demonstrate very limited similarities between the transcriptomes of all our murine aging models and question their reliability to study human cardiovascular senescence
Exploring older women's confidence during route planning
In-car route guidance is automatic, requiring a minimum of time and thinking. This paper explores the use of personalised information when providing instructions for navigating a journey. We focus on older women with a lifetime of experience. Ten female participants were interviewed to elicit their comfort zone with respect to navigating in a car from their own home. Two routes were then devised for each participant, which extended beyond this comfort zone, and presented to them in two different formats. Participants then navigated the route of their least preferred format. Questionnaires and interviews were used to explore the effects of the formats on their confidence, cognitive effort and use of cognitive mapping facilities. The questionnaire data showed that the more detailed instructions supported cognitive mapping processes and the interviews suggested that this support was valued prio
Comparative and functional analysis of intron-mediated enhancement signals reveals conserved features among plants
Introns in a wide range of organisms including plants, animals and fungi are able to increase the expression of the gene that they are contained in. This process of intron-mediated enhancement (IME) is most thoroughly studied in Arabidopsis thaliana, where it has been shown that enhancing introns are typically located near the promoter and are compositionally distinct from downstream introns. In this study, we perform a comprehensive comparative analysis of several sequenced plant genomes. We find that enhancing sequences are conserved in the multi-cellular plants but are either absent or unrecognizable in algae. IME signals are preferentially located towards the 5′-end of first introns but also appear to be enriched in 5′-UTRs and coding regions near the transcription start site. Enhancing introns are found most prominently in genes that are highly expressed in a wide range of tissues. Through site-directed mutagenesis in A. thaliana, we show that IME signals can be inserted or removed from introns to increase or decrease gene expression. Although we do not yet know the specific mechanism of IME, the predicted signals appear to be both functional and highly conserved
Myofilament dysfunction in cardiac disease from mice to men
In healthy human myocardium a tight balance exists between receptor-mediated kinases and phosphatases coordinating phosphorylation of regulatory proteins involved in cardiomyocyte contractility. During heart failure, when neurohumoral stimulation increases to compensate for reduced cardiac pump function, this balance is perturbed. The imbalance between kinases and phosphatases upon chronic neurohumoral stimulation is detrimental and initiates cardiac remodelling, and phosphorylation changes of regulatory proteins, which impair cardiomyocyte function. The main signalling pathway involved in enhanced cardiomyocyte contractility during increased cardiac load is the β-adrenergic signalling route, which becomes desensitized upon chronic stimulation. At the myofilament level, activation of protein kinase A (PKA), the down-stream kinase of the β-adrenergic receptors (β-AR), phosphorylates troponin I, myosin binding protein C and titin, which all exert differential effects on myofilament function. As a consequence of β-AR down-regulation and desensitization, phosphorylation of the PKA-target proteins within the cardiomyocyte may be decreased and alter myofilament function. Here we discuss involvement of altered PKA-mediated myofilament protein phosphorylation in different animal and human studies, and discuss the roles of troponin I, myosin binding protein C and titin in regulating myofilament dysfunction in cardiac disease. Data from the different animal and human studies emphasize the importance of careful biopsy procurement, and the need to investigate localization of kinases and phosphatases within the cardiomyocyte, in particular their co-localization with cardiac myofilaments upon receptor stimulation.</p
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