Search

Prospective studies applying fluoroscopy for assessment of right ventricular (RV) lead position have failed to show clear benefits from RV septal pacing. We investigated the impact of different RV lead positions verified by computed tomography (CT) on the risk of pacing-induced cardiomyopathy (PICM). We retrospectively included 153 patients who underwent routine fluoroscopy-guided pacemaker implantation between March 2012 and May 2020. All patients had normal pre-implant left ventricular ejection fraction (LVEF). Patients attended a follow-up visit including contrast-enhanced cardiac CT and transthoracic echocardiography. Patients were classified as septal or non-septal based on CT analysis. The primary endpoint was PICM (LVEF < 50% with ≥10% decrease after implantation). Based on CT, 48 (31.4%) leads were septal and 105 (68.6%) were non-septal. Over a median follow-up of 3.1 years, 16 patients (33.3%) in the septal group developed PICM compared to 31 (29.5%) in the non-septal group (p = 0.6). Overall, 13.1% deteriorated to LVEF ≤ 40%, 5.9% were upgraded to cardiac resynchronization therapy device, and 14.4% developed new-onset atrial fibrillation, with no significant differences between the groups. This study demonstrated a high risk of PICM despite normal pre-implant left ventricular systolic function with no significant difference between CT-verified RV septal or non-septal lead position.

PURPOSE: To evaluate the association between different right ventricular (RV) lead positions as assessed by cardiac computed tomography (CT) and echocardiographic and clinical outcomes in patients receiving cardiac resynchronization therapy (CRT).METHODS: We reviewed patient records of all 278 patients included in two randomized controlled trials (ImagingCRT and ElectroCRT) for occurrence of heart failure (HF) hospitalization or all-cause death (primary endpoint) during long-term follow-up. Outcomes were compared between RV lead positions using adjusted Cox regression analysis. Six months after CRT implantation, we estimated left ventricular (LV) reverse remodeling by measuring LV end-systolic and end-diastolic volumes by echocardiography. Changes from baseline to 6 months follow-up were compared between RV lead positions. Device-related complications were recorded at 6-month follow-up.RESULTS: During median (interquartile range) follow-up of 4.7 (2.9-7.1) years, the risk of meeting the primary endpoint was similar for patients with non-apical vs. apical RV lead position (adjusted hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.54-1.12, p = 0.17) and free wall vs. septal RV lead position (adjusted HR 1.03, 95% CI 0.72-1.47, p = 0.86). Changes in LV ejection fraction and dimensions were similar with the different RV lead positions. We observed no differences in device-related complications relative to the RV lead position.CONCLUSIONS: In patients receiving CRT, the risk of HF hospitalization or all-cause death during long-term follow-up, and LV remodeling and incidence of device-related complications after 6 months are not associated with different anatomical RV lead position as assessed by cardiac CT.

Background: Cardiac resynchronization therapy (CRT) is an effective treatment for patients with heart failure; however, 30% of patients do not respond to the treatment. We sought to derive patient-specific left ventricle maps of lead placement scores (LPS) that highlight target pacing lead sites for achieving a higher probability of CRT response. Methods: Eighty-two subjects recruited for the ImagingCRT trial (Empiric Versus Imaging Guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy) were retrospectively analyzed. All 82 subjects had 2 contrast-enhanced full cardiac cycle 4-dimensional computed tomography scans: a baseline and a 6-month follow-up scan. CRT response was defined as a reduction in computed tomography–derived end-systolic volume ≥15%. Eight left ventricle features derived from the baseline scans were used to train a support vector machine via a bagging approach. An LPS map over the left ventricle was created for each subject as a linear combination of the support vector machine feature weights and the subject’s own feature vector. Performance for distinguishing responders was performed on the original 82 subjects. Results: Fifty-two (63%) subjects were responders. Subjects with an LPS≤Q 1 (lower-quartile) had a posttest probability of responding of 14% (3/21), while subjects with an LPS≥ Q 3 (upper-quartile) had a posttest probability of responding of 90% (19/21). Subjects with Q 1 3 had a posttest probability of responding that was essentially unchanged from the pretest probability (75% versus 63%, P =0.2). An LPS threshold that maximized the geometric mean of true-negative and true-positive rates identified 26/30 of the nonresponders. The area under the curve of the receiver operating characteristic curve for identifying responders with an LPS threshold was 87%. Conclusions: An LPS map was defined using 4-dimensional computed tomography–derived features of left ventricular mechanics. The LPS correlated with CRT response, reclassifying 25% of the subjects into low probability of response, 25% into high probability of response, and 50% unchanged. These encouraging results highlight the potential utility of 4-dimensional computed tomography in guiding patient selection for CRT. The present findings need verification in larger independent data sets and prospective trials.

Aims This study aims to investigate the long-term occurrence of the composite endpoint of heart failure (HF) hospitalization or all-cause death (primary endpoint) in patients randomized to cardiac resynchronization therapy (CRT) using individualized multimodality imaging-guided left ventricular (LV) lead placement compared with a routine fluoroscopic approach. Furthermore, this study aims to evaluate whether inter-lead electrical delay (IED) is associated with improved response rate of this endpoint. Methods and results We reviewed follow-up data until November 2020 for all 182 patients included in the ImagingCRT trial for the occurrence of HF hospitalization and all-cause death. During median (inter-quartile range) time to primary endpoint/censuring of 6.7 (3.3–7.9) years, the rate of the primary endpoint was 60% (n = 53) in the imaging group compared with 52% (n = 48) in the control group [hazard ratio (HR) 1.22, 95% confidence interval (CI) 0.83–1.81, P = 0.31]. Neither the risk of HF hospitalization (HR 1.11, 95% CI 0.62–1.99, P = 0.72) nor of all-cause death differed between treatment groups (HR 1.23, 95% CI 0.82–1.85, P = 0.32). The risk of the primary endpoint was significantly reduced among those with IED ≥100 ms when compared with those with IED Conclusions In this study, an individualized multimodality imaging-guided strategy targeting LV lead placement towards the latest mechanically activated non-scarred myocardial segment during CRT implantation did not reduce HF hospitalization or all-cause death when compared with routine LV lead placement during long-term follow-up. Targeting the latest electrical activation should be studied as an alternative individualized strategy for optimizing LV lead placement in CRT recipients.

BackgroundCardiac resynchronization therapy (CRT) is an effective treatment for patients with heart failure; however, 30% of patients do not respond to the treatment. We sought to derive patient-specific left-ventricle (LV) maps of lead placement scores (LPS) that highlight target pacing lead sites for achieving a higher probability of CRT response.MethodsEighty-two subjects recruited for the ImagingCRT trial were retrospectively analyzed. All 82 subjects had two contrast-enhanced full-cardiac cycle 4DCT scans: a baseline and a 6-month follow-up scan. CRT response was defined as a reduction in CT-derived end-systolic volume ≥15%. Eight LV features derived from the baseline scans were used to train a support vector machine (SVM) via a bagging approach. An LPS map over the LV was created for each subject as a linear combination of the SVM feature weights and the subject’s own feature vector. Performance for distinguishing responders was performed on the original 82 subjects.ResultsFifty-two (63%) subjects were responders. Subjects with an LPS≤Q1 (lower-quartile) had a posttest probability of responding of 14% (3/21), while subjects with an LPS≥ Q3 (upper-quartile) had a posttest probability of responding of 90% (19/21). Subjects with Q13 had a posttest probability of responding that was essentially unchanged from the pretest probability (75% vs 63%, p=0.2). An LPS threshold that maximized the geometric mean of true-negative and true-positive rates identified 26/30 of the non-responders. The AUC of the ROC curve for identifying responders with an LPS threshold was 87%.ConclusionsAn LPS map was defined using 4DCT-derived features of LV mechanics. The LPS correlated with CRT response, reclassifying 25% of the subjects into low-probability of response, 25% into high-probability of response, and 50% unchanged. These encouraging results highlight the potential utility of 4DCT in guiding patient selection for CRT. The present findings need verification in larger independent data sets and prospective trials.Clinical PerspectiveCardiac resynchronization therapy (CRT) is a proven treatment for patients with heart failure and dyssynchrony; however, approximately 30% of patients do not respond to the treatment. Additionally, the relatively high non-responder rate poses difficulties for the optimal utilization of medical resources; thus, more accurate patient stratification for CRT remains an unmet need. Despite significant efforts focused on using imaging to guide CRT, the results thus far have been ambiguous. Poor reproducibility of echocardiography coupled with the complexity of cardiac magnetic resonance have likely contributed to the poor overall adoption of these methods for pre-CRT assessment. In this work, we describe a metric called the lead placement score (LPS) that combines multiple 4DCT-derived features of left-ventricular (LV) mechanics into a single number for each possible pacing lead location on the LV; the features included in the LPS map have previously been shown to correlate with CRT response. Using a machine learning classifier, a model was constructed with these features and then used to derive the LPS map for each individual subject. The LPS was found to correlate with the probability of a subject responding to CRT. 4DCT is widely available and provides high-resolution images of the full cardiac cycle. Additionally, recent technological advancements have also dramatically reduced the radiation dose from 4DCT scans. The advantages of 4DCT coupled with the promising results reported in this study, highlight the potential utility of 4DCT in the planning of CRT.

OBJECTIVE: The objective of this study was to examine whether left atrial (LA) volumes and function were associated with atrial high-rate episodes (AHREs) in patients with cardiac resynchronization therapy (CRT).METHODS: Ninety-two consecutive patients without prior atrial fibrillation underwent clinical evaluation, echocardiograms, and cardiac computed tomography (CT) before CRT implantation and after 6 months. Left atrial volumes and LA emptying fraction (LAEF) were derived by CT images reconstructed at 5% phase increments of the cardiac cycle. Cox regression was used to assess associations between AHRE and LA anatomical and functional variables.RESULTS: Twenty-two patients (24%) developed AHRE during 1.9 years (SD, 1 year) At baseline, higher LAEF was associated with a lower risk of AHRE (hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.91-0.98; P = 0.003), and large LA minimal (LAmin) volume was related to higher risk of AHRE (HR, 1.03; 95% CI, 1.00-1.06; P = 0.04). When combining LAEF and LAmin volume, only LAEF remained associated with occurrence of AHRE. Higher passive LAEF was associated with lower risk of AHRE (HR, 0.95; 95% CI, 0.91-0.98; P = 0.003).CONCLUSIONS: In patients with CRT, low preimplant LAEF measured by cardiac CT was independently associated with device-detected AHRE.

BACKGROUND: Cardiac resynchronization therapy (CRT) induces segmental left ventricular (LV) remodeling. LV lead position (LV-LP) impacts response to CRT and remodeling.OBJECTIVE: We aimed to assess segmental remodeling concordant, adjacent, and remote to LV-LP using cardiac computed tomography (CT).METHODS: We included patients from the ImagingCRT (Empiric versus Imaging-Guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy) Trial. A dynamic cardiac CT was performed at baseline and after 6 months. We assessed systolic wall thickening (WT) and exact LV-LP from the CT scans according to a 16 segmental model. Response to CRT was defined as ≥15% reduction in LV end-systolic volume.RESULTS: A total of 107 consecutive patients were included. The change in WT from baseline to follow-up was -19 % (95% CI -25 to -13, pCONCLUSION: During CRT, the systolic WT increases in segments remote to LV-LP, decreases in segments concordant, and remains unchanged in adjacent segments. Only marginal changes occur in wall thickness. In non-responders with non-ischemic cardiomyopathy, deleterious changes in segmental myocardial function occur, and further studies on how to treat these patients best are warranted.

BACKGROUND: Device therapy in addition to medical treatment improves prognosis in a subset of patients with heart failure and reduced ejection fraction. However, some patients remain symptomatic or their heart failure even progresses despite cardiac resynchronization therapy (CRT). The aim of the study was to evaluate the proportion of patients who could benefit from optimization of medical therapy using sacubitril/valsartan, ivabradine, or both following CRT implantation.METHODS: We conducted a post hoc analysis of a single-centre, patient and outcome-assessor blinded, randomized-controlled trial, in which patients scheduled for CRT were randomized to empiric (n = 93) or imaging-guided left-ventricular lead placement (n = 89). All patients underwent clinical evaluation and blood sampling at baseline and 6 months following CRT implantation. The proportion of patients meeting the indication for sacubitril/valsartan (irrespective of angiotensin-converting enzyme inhibitor or angiotensin 2 receptor blocker dosage) and/or ivabradine according to current guidelines was evaluated at baseline and after 6 months.RESULTS: Of 182 patients with an indication for CRT, 146 (80%) also had an indication for optimization of medical therapy at baseline by adding sacubitril/valsartan, ivabradine, or both. Of the 179 survivors at 6 months, 136 (76%) were still symptomatic after device implantation; of these, 51 (38%) patients had an indication for optimization of medical therapy: sacubitril/valsartan in 37 (27%), ivabradine in 7 (5%), and both drugs in 7 (5%) patients. Seven (18%) patients without indication at baseline developed an indication for medical optimization 6 months after CRT implantation.CONCLUSION: In the present study, 38% of those who remained symptomatic 6 months after CRT implantation were eligible for optimization of medical therapy with sacubitril/valsartan, ivabradine, or both. Patients with CRT may benefit from systematic follow-up including evaluation of medical treatment.

Aim Left ventricular (LV) lead position at the latest mechanically activated non-scarred myocardial LV region confers improved response to cardiac resynchronization therapy (CRT). We conducted a double-blind, randomized controlled trial to evaluate the clinical benefit of multimodality imaging-guided LV lead placement in CRT. Methods and results Patients were allocated (1:1) to imaging-guided LV lead placement using cardiac computed tomography (CT) venography, 99mTechnetium myocardial perfusion imaging, and speckle-tracking echocardiography radial strain to target the optimal coronary sinus (CS) branch closest to the non-scarred myocardial segment with latest mechanical activation (imaging group, n = 89) or to routine LV lead implantation in a posterolateral region with late electrical activation (control group, n = 93). The primary endpoint was clinical non-response to CRT [≥1 of the following after 6 months: (1) death, (2) heart failure hospitalization, or (3) no improvement in New York Heart Association class and

BACKGROUND: QRS narrowing after CRT is a predictor of patient outcome. Further narrowing can be obtained by interventricular pacing delay (VVd) optimization, raising interest to inter and intraobserver variation in manual measurements of QRS duration.METHODS: (a) Variation in intrinsic rhythm QRS duration in CRT patients with LBBB: In 40 intrinsic 12-lead ECGs, six observers measured QRS duration defined as widest QRS in any lead. In 20 of these ECGs, two observers repeated the measurements. (b) Variation in paced QRS duration at different VVd settings and agreement in selecting the narrowest QRS: In 20 CRT patients, five paced ECGs were recorded at different VVds. The most frequently selected VVd(s) estimated to cause the narrowest QRS in each patient defined the optimal VVd. Two observers repeated the measurements and VVd selections.RESULTS: Absolute interobserver difference in measured QRS duration in intrinsic rhythm ECGs was mean 2 ms, range (-40; 40 ms), mean limits of agreement (LoA): -21; 25 ms. Absolute interobserver difference in measured QRS duration in paced ECGs was mean 3 ms, range (-50; 60 ms), mean LoA: -20; 27 ms. There was no difference in LoA between intrinsic and paced QRS duration (lower limit p = 0.68; upper limit p = 0.44). The optimal VVd was included in 17/20 (85%) of the VVd selections by six observers. Interobserver variation was comparable with the intraobserver variation.CONCLUSIONS: Interobserver variation and intraobserver variation in manually measured paced and intrinsic rhythm QRS duration are clinically acceptable and comparable in a cohort of CRT patients. Inter and intraobserver reproducibility for selecting the optimal VVd is good and warrants manual VVd optimization for QRS narrowing in CRT.

OBJECTIVES: Before cardiac resynchronization therapy (CRT) implantation, cardiac computed tomography (CT) can provide assessment of cardiac venous anatomy and visualize left ventricular (LV) myocardial scar. We hypothesized that localization and burden of transmural myocardial scar verified by cardiac CT are associated with echocardiographic and clinical response to CRT.METHODS: We prospectively included 140 CRT recipients undergoing preimplant cardiac CT. We assessed transmural scar, defined as hypoperfusion involving more than one-half of the myocardial wall in each LV segment using a 17-segment model. Echocardiographic nonresponse was defined as less than 5% absolute improvement in LV ejection fraction at 6 months' follow-up. Clinical nonresponse was defined as 1 or more of the following at 6 months' follow-up: death, heart failure hospitalization, or no improvement in New York Heart Association class and less than 10% increase in 6-minute walk-test distance.RESULTS: Higher burden of myocardial scar was associated with echocardiographic nonresponse (adjusted odds ratio, 3.02; 95% confidence interval, 1.03-8.91; P = 0.045). Scar concordant or adjacent to LV pacing site was associated with echocardiographic nonresponse (adjusted odds ratio, 8.2; 95% confidence interval, 1.51-44.27; P = 0.015). No association between scar and clinical nonresponse was demonstrated.CONCLUSIONS: Higher scar burden and scar in proximity to the LV pacing site assessed by cardiac CT are associated with echocardiographic nonresponse to CRT. Burden and location of scar were not associated with clinical nonresponse. Further large-scale studies are needed to assess the potential association between myocardial scar detected by cardiac CT and clinical CRT outcome.

Aims: In a randomized trial of cardiac resynchronization therapy (CRT), a presumed optimal left ventricular (LV) lead position close to the latest mechanically activated non-scarred myocardium was achieved in 98% of patients by standard implantation. We evaluated whether inter-lead electrical delay (IED) was associated with response to CRT in these patients.Methods and results: We prospectively included 160 consecutive patients undergoing CRT. Pre-implant speckle-tracking echocardiography radial strain and 99mTc myocardial perfusion imaging determined the latest mechanically activated non-scarred myocardial segment. We measured procedural IED as the time interval between sensed signals in right ventricular and LV lead electrograms. All patients had LV pacing site concordant or adjacent to the latest mechanically activated non-scarred segment verified by cardiac computed tomography. Response to CRT was defined as ≥15% reduction in LV end-systolic volume at 6 months follow-up. Selecting a practical IED cut-off value of 100 ms, more patients with long IED than patients with short IED responded to CRT (87 vs. 68%; P = 0.004). In multivariate logistic regression analysis, IED ≥100 ms remained associated with CRT response after adjusting for baseline characteristics, including QRS duration and scar burden [odds ratio 3.19 (1.24-8.17); P = 0.01]. Categorizing IED by tertiles, CRT response improved with longer IED (P = 0.03). Comparable response rates were observed in patients with a concordant and adjacent LV lead position.Conclusion: A longer IED was associated with more pronounced LV reverse remodelling response in CRT recipients with a presumed optimal LV lead position concordant or adjacent to the latest mechanically activated non-scarred segment.

Offshore wind fluctuations are such that dedicated prediction and control systems are needed for optimizing the management of wind farms in real-time. In this paper, we present a pioneer experiment – Radar@Sea – in which weather radars are used for monitoring the weather at the Horns Rev offshore wind farm, in the North Sea. First, they enable the collection of meteorological observations at high spatio-temporal resolutions for enhancing the understanding of meteorological phenomena that drive wind fluctuations. And second, with the extended visibility they offer, they can provide relevant inputs to prediction systems for anticipating changes in the wind fluctuation dynamics, generating improved wind power forecasts and developing specific control strategies. However, integrating weather radar observations into automated decision support systems is not a plug-and-play task, and it is important to develop a multi-disciplinary approach linking meteorology and statistics. Here, (i) we describe the settings of the Radar@Sea experiment, (ii) we report the experience gained with these new remote sensing tools, (iii) we illustrate their capabilities with some concrete meteorological events observed at Horns Rev and (iv) we discuss the future perspectives for weather radars in wind energy. Copyright © 2013 John Wiley & Sons, Ltd.

To evaluate whether baseline left atrial (LA) volume and function were associated with clinical or echocardiographic response to cardiac resynchronization therapy (CRT), and to determine LA reverse remodeling as assessed by computed tomography (CT). We prospectively included patients receiving a CRT system who underwent dynamic cardiac CT with measurement of LA size and function before and 6 months after implantation. Patients alive not hospitalized for heart failure, and improving ≥1 NYHA class or ≥10% in 6-min walk test after 6 months follow-up were classified as clinical responders. Echocardiographic response was defined as ≥15% reduction in left ventricular (LV) end-systolic volume. We included 138 patients, of whom 95 (69%) were clinical responders and 114 (83%) were echocardiographic responders. We found no association between baseline measures of LA volume or function and clinical or echocardiographic response. Mean reduction in LA maximum and minimum volumes at 6 months were 3.3 ± 12.7 ml/m(2) (p = 0.004) and 2.6 ± 11.4 ml/m(2) (p = 0.01) corresponding to a relative reduction of 4.1 and 5.0%, respectively. LV end-systolic relative volume reduction was 35.2 ± 22.4% (p

The selection of users for participation in IT projects involves trade-offs between multiple criteria, one of which is selecting a representative cross-section of users. This criterion is basic because trading it for other criteria means basing designs on information biased toward some user groups at the expense of others. Based on interviews in development and customer organizations we find that their criteria for user selection favor persons who can contribute to the progress of the IT project over persons who are representative of the full range of users. A highly valued contribution from participating users is the ability to advocate a vision for the system and champion its organizational implementation. A survey in one customer organization shows that respondents' personal traits explain up to 31% of the variation in their experience of aspects of the usability of a recently introduced system. Thus, unless participating users are representative as to these personal traits, IT projects may, inadvertently, bring about systems that will fail to satisfy many users.

Udgivelsesdato: 2010-Jul-28 AIMS: To examine left ventricular (LV) longitudinal systolic myocardial function in patients with hypertrophic obstructive cardiomyopathy (HOCM) before and after transcoronary ablation of septal hypertrophy (TASH). METHODS AND RESULTS: Twenty-three of 39 consecutive patients with HOCM had serial two-dimensional (2D) echocardiograms available for speckle tracking analyses before and up to 36 months after TASH. Before TASH, overall LV myocardial longitudinal systolic 2D strain was decreased despite normal LV ejection fraction (EF). A significant reduction of LV mass and left ventricular outflow tract (LVOT) gradients occurred during long-term follow-up after TASH, but this was not accompanied by improvement of average LV longitudinal systolic strain. However, in the basal LV segments remote to the site of alcohol injection longitudinal systolic strain increased [baseline: -13.1 +/- 5.4%; 1 month: -16.0 +/- 5.5% (NS); 12 months: -16.5 +/- 4.9% (P < 0.05 vs. baseline); 36 months: -17.4 +/- 4.2% (P < 0.01 vs. baseline)]. In contrast, the alcohol-treated basal segments of the septum and adjacent myocardium showed unchanged strain over time. CONCLUSION: Average LV longitudinal myocardial systolic function is depressed in HOCM despite normal LV EF. TASH-induced reduction of the LVOT obstruction does not improve average LV longitudinal systolic 2D strain. This is in contrast to global improvement of longitudinal systolic function after valve replacement in aortic valve stenosis. The discrepancy may be caused by the fact that HOCM is a primary myocardial disease.

AIMS: Paced electrocardiogram characteristics to confirm left ventricular (LV) and right ventricular (RV) pacing sites in cardiac resynchronization therapy (CRT) have not been validated with accurate knowledge of pacing lead positions. We aimed to evaluate the ability of the paced QRS morphology to differentiate between various LV and RV lead positions using cardiac computed tomography (CT) as the reference for LV and RV pacing site.METHODS AND RESULTS: Ninety-seven CRT patients were included. The QRS morphology was evaluated during forced LV-only and RV-only pacing. Pacing lead positions were assessed in a standard LV 16-segment model and a simplistic RV 6-segment model using cardiac CT. Ten patients with LV lead displacement or a LV pacing site outside the non-apical free wall were excluded from the analysis of the LV paced QRS complex. Pacing within the LV free wall was associated with a superior and a right-axis deviation (P = 0.02 and 0.04, respectively). Pacing from basal LV segments mainly produced a late (V5 or later) precordial QRS transition as compared with mid-LV pacing (P = 0.001). No significant associations were found between RV pacing site and QRS axis or precordial transition. Different QRS morphologies were observed during single-chamber pacing from identical LV or RV myocardial segments.CONCLUSION: Weak associations exist between LV and RV pacing sites and the paced QRS axis. None of the paced QRS characteristics can be used to reliably confirm specific LV and RV pacing sites in CRT patients.

AIMS: Fluoroscopy is the routine method for localizing left ventricular (LV) and right ventricular (RV) lead positions in cardiac resynchronization therapy (CRT). However, the ability of fluoroscopy to determine lead positions in a standard ventricular segmentation is unknown. We aimed to evaluate the accuracy and reproducibility of fluoroscopy to determine LV and RV lead positions in CRT when compared with cardiac computed tomography (CT).METHODS AND RESULTS: Fifty-nine patients undergoing CRT were included. Bi-plane fluoroscopy and cardiac CT were evaluated in all patients. Pacing lead positions were assessed in a standard LV 16-segment model and in a simplistic RV 8-segment model. Four patients with LV lead displacement were excluded from the agreement analysis of LV lead position. Agreement of LV lead position between fluoroscopy and cardiac CT was observed in 19 (35%) patients with fluoroscopy demonstrating a 1-segment and ≥2-segment error in 30 (55%) and 6 (11%) patients, respectively. Agreement of RV lead position was found in 13 (22%) patients with fluoroscopy showing a 1-segment and ≥ 2-segment error in 28 (47%) and 18 (31%) patients, respectively. The interobserver agreement on LV and RV lead positions was poor for fluoroscopy (kappa 0.20 and 0.23, respectively) and excellent for cardiac CT (kappa 0.87 and 0.85, respectively).CONCLUSION: Fluoroscopy is inaccurate and modestly reproducible when assessing LV and RV lead positions in a standard ventricular segmentation when compared with cardiac CT. Cardiac CT should be applied to determine the exact pacing site in future research evaluating the optimal pacing lead position in CRT.

Udgangspunktet for nærværende specialerapport har været en undren over, hvorfor der, i den teoretiske litteratur om brugerinddragende it-udvikling, ikke fokuseres mere på selve udvælgelsen af brugere, end der gør. Vi mener, at valget af brugere kan have en stor effekt på det endelige resultat af et systemudviklingsprojekt og argumenterer derfor for, at der skal være et større fokus på brugerudvælgelsen. I specialet er der opstillet en model til ekspliciteringen af udvælgelsesprocessen - MEBU-modellen. Modellen består af syv elementer, som bør overvejes forud for de udvælgelsesprocesser, der finder sted ifm. brugerinddragende it-udviklingsprojekter. Den er baseret på litteraturstudier af teorier indenfor dette datalogiske felt og forskellige tilgange til kategorisering indenfor det kommunikationsfaglige felt. Desuden er den baseret på empiriske studier hos fire danske udviklervirksomheder og et udvalg af disse virksomheders kunder. Modellens formål er at danne et diskussionsgrundlag for, hvordan udviklere i it-virksomheder udvælger deres brugere, og få italesat evt. implicitte antagelser. Grundet specialets fokus på selve opstillingen af modellen, er den ikke blevet evalueret i praksis. Derfor er en oplagt mulighed for videre forskning at evaluere og viderudvikle modellen ifm. konkrete brugerinddragende it-projekter. Dog bidrager modellen til litteraturen om brugerinddragende itudvikling med et forøget fokus på udvælgelsen af brugere.

The measurement of inflow to a wind turbine rotor was made with a spinner anemometer on a 2 MW wind turbine in a wind farm of eight wind turbines. The wind speed, yaw misalignment and flow inclination angle was measured during a five months measurement campaign. Angular measurements were calibrated by yawing the wind turbine in and out of the wind in stopped conditions. Wind speed was calibrated relative to a met mast in a wake-free wind sector during operation. The calibration measurements were used to determine the basic k1 and k2 constants of the spinner anemometer and a four parameter induction factor function. Yaw measurements and turbulence measurements, where the average wind speed was corrected to the far field with the induction function, showed good correlation with mast measurements. The yaw misalignment measurements showed a significant yaw misalignment for most of the wind speed range, and also a minor symmetric yaw misalignment pattern. The flow inclination angle showed slight variation of inflow angle with wind speed and clear wake swirl patterns in the wakes of the other wind turbines. Turbulence intensity measurements showed clear variations from low turbulence in the wake-free wind sector to high turbulence in the wakes of the other wind turbines.

Cardiac resynchronization therapy (CRT) is an established treatment in heart failure patients. However, a large proportion of patients remain nonresponsive to this pacing strategy. Left ventricular (LV) lead position is one of the main determinants of response to CRT. This study aims to clarify whether multimodality imaging guided LV lead placement improves clinical outcome after CRT. The ImagingCRT study is a prospective, randomized, patient- and assessor-blinded, two-armed trial. The study is designed to investigate the effect of imaging guided left ventricular lead positioning on a clinical composite primary endpoint comprising all-cause mortality, hospitalization for heart failure, or unchanged or worsened functional capacity (no improvement in New York Heart Association class and

The wind turbine operational charac-teristics, power measurements and the meteorological measurements as 10 minute statistical data from Horns Rev offshore wind farm have been identified, synchronized, quality screened and stored in a common database. A number of flow cases have been identified to describe the flow inside the wind farm and the flow deficits along rows of wind turbines have been determined for different inflow directions and wind speed intervals. Furthermore the maximum power deficit has been determined as function of ambient turbulence intensity.

The substantial impact of wind power fluctuations at large offshore wind farms calls for the development of dedicated monitoring and prediction approaches. Based on recent findings, a Local Area Weather Radar (LAWR) was installed at Horns Rev with the aim of improving predictability, controlability and potentially maintenance planning. Additional images are available from a Doppler radar covering the same area. The parallel analysis of rain events detection and of regime sequences in wind (and power) fluctuations demonstrates the interest of employing weather radars for a better operation and management of offshore wind farms.