The Use of Immersive and Virtual Reality Technologies to Enable Nursing Students to Experience Scenario-Based, Basic Life Support Training-Exploring the Impact on Confidence and Skills.

The link between effective basic life support and survival following cardiac arrest is well known. Nurses are often first responders at in-hospital cardiac arrests and receive annual basic life support training to ensure they have the adequate skills, and student nurses are taught this in preparation for their clinical practice. However, it is clear that some nurses still lack confidence and skills to perform basic life support in an emergency situation. This innovative study included 209 participants, used a mixed-methods approach, and examined three environments to compare confidence and skills in basic life support training. The environments were nonimmersive (basic skills room), immersive (immersive room with video technology), and the Octave (mixed reality facility). The skills were measured using a Laerdal training manikin (QCPR manikin), with data recorded on a wireless Laerdal Simpad, and confidence levels before and after training were measured using a questionnaire. The nonimmersive and the immersive rooms were familiar environments, and the students felt more comfortable, relaxed, and, thus, more confident. The Octave offered the higher level of simulation utilizing virtual reality technology. Students felt less comfortable and less confident in the Octave; we assert that this was because the environment was unfamiliar. The study identified that placing students in an unfamiliar environment influences the confidence and skills associated with basic life support; this could be used as a way of preparing student nurses with the necessary emotional resilience to cope in stressful situations.

Bachmann's bundle and coronary sinus ostial pacing accentuate left atrial electrical dyssynchrony in an acute canine model.

INTRODUCTION: In patients with intraatrial conduction delay and sinus node (SN) dysfunction, pacing Bachmann's bundle (BBR) and coronary sinus ostium (CSO) has been suggested to achieve atrial resynchronization with potential beneficial impact on atrial fibrillation and diastolic heart failure. Clinical studies have not shown superiority of one approach. METHODS AND RESULTS: We studied electrical activation sequence in an open-chest acute canine model of normal atrial function in 8 mongrel dogs under general anesthesia. Bipolar plunge electrodes were distributed over the surface of the atria during unifocal pacing, and intracardiac activation sequence was observed. SN pacing resulted in near-simultaneous activation at midline sites (BBR and CSO); the left atrium (LA) was activated by anterior and posterior wavefronts simultaneously propagating septally to laterally and meeting at the low-lateral perimitral LA. Right atrial appendage (RAA) pacing created intra-RA conduction delay and delayed onset of LA activation. Pacing from RAA, CSO, and BBR resulted in nonsimultaneous activation at midline sites and produced an anteroposterior gradient of LA activation. This phenomenon was seen to the greatest degree with midline pacing and shifted the site of latest activation away from the low-lateral perimitral LA in all pacing configurations except SN pacing. CONCLUSION: Pacing-induced intra-LA activation dispersion is enhanced with midline atrial pacing, and secondarily shifts the site of latest activation away from the lateral mitral annulus. Measuring atrial activation times to the low-lateral perimitral LA can underestimate the degree of atrial dyssynchrony and be misinterpreted as atrial synchrony. Establishing clinical impact requires evaluation of human data.

Cochrane review on 'Statins for the treatment of dementia'.

OBJECTIVES: This review aimed to assess the clinical efficacy and tolerability of statins in the treatment of dementia. METHODS: We searched the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS, as well as many trials registries and grey literature sources (27 October 2008). Double-blind, randomized controlled trials of statins given for at least 6 months in people with a diagnosis of dementia were included. Two independent authors extracted and assessed data independently against the inclusion criteria. Data were pooled where appropriate and entered into a meta-analysis. RESULTS: Three studies were identified (748 participants, age range 50-90 years). All patients had a diagnosis of probable or possible Alzheimer's disease according to standard criteria, and most patients were established on a cholinesterase inhibitor. Change in Alzheimer's Disease Assessment Scale cognitive subscale from baseline was a primary outcome in three studies; when data were pooled, statins did not provide any beneficial effect in this cognitive measure (mean difference -1.12; 95% confidence interval -3.99, 1.75; p = 0.44). All studies provided a change in Mini-Mental State Examination from baseline; there was no significant benefit from statins in this cognitive measure when the data were pooled (mean difference -1.53; 95% confidence interval -3.28; 0.21, p = 0.08). There were no studies identified assessing the role of statins in treatment of vascular dementia. There was no evidence that statins were detrimental to cognition. CONCLUSIONS: There is insufficient evidence to recommend statins for the treatment of dementia.

Firearm Acoustic Detection in Hartford, Connecticut: Outcomes of a Trauma Center - Law Enforcement Collaboration.

Introduction Firearm homicide is a leading cause of violence-related death in the United States.Unfortunately, more than 80% of illegal firearm discharges are never reported to police by traditional means.ShotSpotterTM (Newark, California) is an acoustic firearm event detection system that can localize gunfire, prompting police, and subsequent emergency medical services (EMS) presence. Previously reported healthcare effects of acoustic detection are speculative in nature. We sought to investigate Hartford, Connecticut's experience with ShotSpotter​​​​​​​TM given its smaller size and broad coverage.  Methods The three trauma centers in Hartford (two for adults and one for pediatric) collaborated with the Hartford Police to review outcomes of victims with acoustically detected gunshots and compare them to those who went undetected. We performed a retrospective review of patients who presented with gunshot wounds (GSW) over a 30-month period, from January 1, 2016 to June 30, 2018. Victim location and acoustic detection were reconciled by the police department and hospital staff independently. Patients were individually matched for location, prehospital response, treatment durations, and hospital outcomes. Results Of 387 GSW, 157 (40.6%) presented via EMS and were included in the sample. Of these, 89 correlated to a detection event (56.7%) and 68 had no correlating event (43.3%). These two groups had no difference in prehospital treatment times, scene and transport duration, and injury severity. Further, the need for surgery or transfusion, lengths of stay, and disposition, including mortality, did not differ. Conclusions Despite limited previous reports demonstrating conferred benefits to acoustic detection of gunshots, Hartford's experience showed no benefit. The potential for such systems to act as early warning systems is evident but may depend on a city's resources, geography, and technology.

Statins for the treatment of dementia.

BACKGROUND: The use of statin therapy in established Alzheimer's disease (AD) or vascular dementia (VaD) is a relatively unexplored area. In AD ss-amyloid protein (Ass) is deposited in the form of extracellular plaques and previous studies have determined Ass generation is cholesterol dependent. Hypercholesterolaemia has also been implicated in the pathogenesis of VaD. Due to the role of statins in cholesterol reduction it is biologically plausible they may be efficacious in the treatment of AD and dementia. OBJECTIVES: To assess the clinical efficacy and tolerability of statins in the treatment of dementia. SEARCH STRATEGY: We searched the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS, as well as many trials registries and grey literature sources (27 October 2008). SELECTION CRITERIA: Double-blind, randomized controlled trials of statins given for at least six months in people with a diagnosis of dementia. DATA COLLECTION AND ANALYSIS: Two independent authors extracted and assessed data independently against the inclusion criteria. Data were pooled where appropriate and entered into a meta-analysis. MAIN RESULTS: Three studies were identified (748 participants, age range 50-90 years). All patients had a diagnosis of probable or possible AD according to standard criteria and most patients were established on a cholinesterase inhibitor. Treatment in ADCLT 2005 consisted of 80mg atorvastatin compared to placebo for 52 weeks, serum low density lipoprotein (LDL) cholesterol was reduced by 54% in the atorvastatin group. Treatment in Simons 2002 consisted of 40mg simvastatin compared to placebo for 26 weeks, serum LDL cholesterol was reduced by 52% in the simvastatin group. Treatment in LEADe 2010 consisted of 80mg atorvastatin compared to placebo for 72 weeks, LDL cholesterol was reduced by 50.2% by month 3 and remained constant through month 18. Change in Alzheimer's Disease Assessment Scale- cognitive subscale (ADAS-Cog) from baseline was a primary outcome in 3 studies; when data were pooled there was considerable heterogeneity so the random effects model was used, statins did not provide any beneficial effect in this cognitive measure [mean difference -1.12, 95% CI -3.99, 1.75, p = 0.44]. All studies provided change in Mini Mental State Examination (MMSE) from baseline; again random effects model was used due to considerable heterogeneity: there was no significant benefit from statins in this cognitive measure when the data were pooled [mean difference -1.53, 95% CI -3.28, 0.21, p = 0.08]. There was some evidence that patients on statins in ADCLT 2005 maintained better cognitive function if serum cholesterol was high at baseline, MMSE was higher at baseline or if they had an apolipoprotein E4 allele present. This would need to be confirmed in larger studies however. Treatment related adverse effects were available from two studies, LEADe 2010 and Simons 2002; when data were pooled there was no significant difference between statins and placebo [odds ratio 2.45, 95% CI 0.69, 8.62, p = 0.16]. There was no significant difference in global function, behaviour or activities of daily living in the statin and placebo groups. One large randomised controlled trial (RCT) ( CLASP 2008) has not yet published its results. There were no studies identified assessing role of statins in treatment of VaD. There was no evidence that statins were detrimental to cognition. AUTHORS' CONCLUSIONS: There is insufficient evidence to recommend statins for the treatment of dementia. Analysis from the studies available, including one large RCT, indicate statins have no benefit on the outcome measures ADAS-Cog or MMSE. We need to await full results from CLASP 2008 before we can be certain. This Cochrane review will be updated as these results become available.

Pacing lead implantation without live fluoroscopy: feasibility of acute success in the live canine model.

INTRODUCTION: Fluoroscopic visualization for transvenous pacing lead placement necessitates lead shielding to minimize radiation exposure. An electromagnetic (EM) navigation system that integrates real-time intracardiac tracking within an anatomic navigation environment may provide an effective alternative for lead delivery that obviates live fluoroscopy. We assessed feasibility of pacing lead implantation with electromagnetic tracking guided solely by radiographic virtual navigation and compared this to fluoroscopy-guided implants in a canine model. METHODS: Seven mongrel dogs with normal hearts were randomized to 47 pacing lead placements in the right atrium (RA) or right ventricle (RV) guided by single-plane fluoroscopy, or an experimental EM navigation system guided by registered fluoroscopic snapshots obtained before implant (EMN). Ability to achieve successful lead delivery acutely was assessed, and pacing parameters as well as fluoroscopy and implant times were measured. Means were compared using a paired t-test. RESULTS: All lead delivery attempts were acutely successful. One atrial lead dislodged with EMN, resulting in 46 successful pacing attempts. There was no statistical difference in pacing parameters and time for lead placement between the approaches (EMN vs fluoroscopic navigation [mean +/- SD]: RA threshold 1.15 V +/- 0.98 V vs 1.95 V +/- 0.98 V [P = NS], RV threshold 1.18 V +/- 0.58 V vs 1.42 V +/- 0.63 V [P = NS], implant time 4:38 +/- 2:37 minutes vs 4:44 +/- 2:38 minutes [P = NS]). No live fluoroscopy was required for EMN implants. CONCLUSION: Pacing lead placement with an EM system guided by preprocedural fluoroscopic views is feasible and comparable to fluoroscopic navigation, and avoids the use of live fluoroscopy.

Statistical match of the March 1996 Current Population Survey and the 1995 National Health Interview Survey.

OBJECTIVES: Statistical matching is a method used to combine two files when it is unlikely that individuals on one file are also on the other file. The objectives of this report are to document and evaluate statistical matches of the March 1996 Current Population Survey (CPS) and the 1995 National Health interview Survey (NHIS) and give recommendations for improving future matches. The CPS-NHIS match was motivated by the need for a data set with data on health measures and family resources for use in policy analyses. METHODS: Three statistical matches between the March 1996 CPS and the 1995 NHIS are described in this report. All three matches used person-level constrained matching with partitioning and a predictive mean matching algorithm to link records on the two files. For two of the matches, the CPS served as the Host file and the NHIS served as the Donor file; for the third match, the NHIS was the Host file and the CPS was the Donor file. RESULTS: The results suggest that the constrained predictive mean matches of the March 1996 CPS and the 1995 NHIS successfully combined some of the information on the two files, but that relationships among some Host and Donor variables on the matched file may be distorted. The evaluation of the matches suggested that the variables used to partition the Host and Donor files prior to matching and the variables involved in the predictive mean matching play an important role in determining whether relationships among variables on the matched file correctly represent relationships among those variables in the population. The evaluation also indicated that estimates for small subgroups may be especially subject to error. The results reinforce the need to proceed cautiously when exploring relationships among Host and Donor variables on a statistically matched file.

A prospective evaluation of the outcome after small saphenous varicose vein surgery with one-year follow-up.

OBJECTIVE: The aim was to examine the effect of various surgical maneuvers during standard surgery for small saphenous varicose veins (SSV). METHODS: This was a prospective cohort study of patients that underwent small saphenous varicose vein surgery. Two-hundred nineteen consecutive patients (234 legs) with isolated primary or recurrent small saphenous varicose veins undergoing surgery were enrolled in a multicenter study involving nine vascular centers in the United Kingdom. Operative technique was determined by individual surgeon preference; clinical and operative details, including the use of stripping, were recorded. Clinical examination (recurrence rates) and duplex imaging (superficial and deep incompetence) were evaluated at six weeks and one year after surgery. RESULTS: A total of 204 legs were reviewed at one year; 67 had small saphenous varicose vein stripping, 116 had saphenopopliteal junction (SPJ) disconnection only, and the remainder had miscellaneous procedures. The incidence of visible recurrent varicosities at one year was lower after SSV stripping (12 of 67, 18%) than after disconnection only (28 of 116, 24%), although this did not reach statistical significance. There was no significant difference in the rate of numbness at one year between those who had SSV stripping (20 of 71, 28%) and those who had disconnection only (38 of 134, 28%). The rate of SPJ incompetence detected by duplex at one year was significantly lower in patients who underwent SSV stripping (9 of 67, 13%) than in those who did not (37 of 115, 32%) (P < .01). CONCLUSION: Stripping of the SSV significantly reduced the rate of SPJ incompetence after one year without increasing the rate of complications.

Feasibility and validation of registration of three-dimensional left atrial models derived from computed tomography with a noncontact cardiac mapping system.

OBJECTIVES: The purpose of this study was to determine the feasibility and assess the validity of registering three-dimensional (3D) models from computed tomographic (CT) images using a cardiac mapping system. BACKGROUND: Registration of 3D anatomic models with an interventional system could help identify and navigate mapping and ablation catheters over a complex structure such as the left atrium (LA). METHODS: ECG-gated, contrast-enhanced cardiac CT imaging was performed in 14 patients with atrial fibrillation. Segmentation was used to create 3D models of the LA. The 3D models were registered with the mapping system using a series of fiducial points. Registration was accomplished retrospectively in the first 10 patients, and catheter navigation was visualized from recorded data. In the final four patients, registration was accomplished in real time during electrophysiologic study. The mapping catheter position, as it was navigated inside the LA, was applied to the registered model in real time. For the validation study, temporary pacing leads were implanted in the LA of 10 dogs. Following this, CT scanning, segmentation, LA model importation, and registration was described previously. After registration, a mapping catheter was positioned at the site of each buried lead according to the registered model with no fluoroscopic guidance. A radiofrequency lesion was created at this location, and the dog was sacrificed, the heart removed and stained, and the distance between the buried lead and the lesion measured. RESULTS: During the feasibility study, the location of the catheter in the registered model correlated with fluoroscopy, angiography, and intracardiac electrograms. LA endocardial potentials during sinus rhythm and any premature atrial contractions also were successfully delineated over the registered models. In the validation study, the mean target registration error was 2.0 +/- 3.6 mm. CONCLUSIONS: Registration of CT-derived 3D models of the LA using a cardiac mapping system is feasible and accurate.

Catheter location, tracking, cardiac chamber geometry creation, and ablation using cutaneous patches.

OBJECTIVE: The ability to construct a three-dimensional (3-D) surface model of the endocardium and track the location of catheters within a cardiac chamber, using only cutaneous patches, would be a useful advancement in treating arrhythmias. We tested the feasibility of such a system, Ensite NavX (Endocardial Solutions, Inc., St. Paul, MN, USA), in patients undergoing catheter ablation for SVTs. METHODS: Sixteen patients with 20 arrhythmias undergoing ablation were selected. Skin electrode patches were placed on the chest to create a 3-D coordinate system. A low-amplitude, 5.7 kHz signal emitted from the patches was received by conventional catheters positioned in the heart. Catheter location was determined by measuring the field strength received by the catheters. Location points were successively acquired while catheters were moved throughout the chamber. This information was collected and processed by a workstation to create a detailed 3-D model of the endocardial surface. Anatomic landmarks were labeled on the model as the mapping catheter was navigated. 3-D cardiac chamber geometry reconstruction, landmark labeling, and real time catheter tracking were performed successfully in all patients. Up to six catheters, with a total of up to 26 intracardiac electrodes, were tracked simultaneously. RESULTS: Constructed geometries, including major vessels and valves, correlated closely with traditional anatomic models as well as intracardiac recordings and fluoroscopic images. CONCLUSIONS: Real-time catheter tracking and 3-D cardiac chamber model construction is feasible using cutaneous patches and conventional catheters. This approach may be useful in the treatment of patients with cardiac arrhythmias where ablation therapy is primarily anatomically based.

Effect of electrical stimulation on arteriogenesis and angiogenesis after bilateral femoral artery excision in the rabbit hind-limb ischemia model.

The effects of electrical stimulation (ES) on arteriogenesis (the opening of preexisting collaterals) and angiogenesis (formation of new capillaries) were studied after acute bilateral hind limb ischemia was induced via bilateral femoral artery excision in a rabbit model. The study evaluated the rabbit hind limbs' normal response to acute ischemia and to application of ES by calculating changes in arterial and capillary densities. Comparisons were made with our prior study, in which the femoral artery was unilaterally excised, as we attempted to expand on the topics of arteriogenesis and angiogenesis. Twelve adult New Zealand white rabbits were randomly assigned to 1 of 2 series. In Series 1, the control group, both femoral arteries were excised and no ES was applied. In Series 2, both femoral arteries were excised and ES was applied to the left limb. One lead was implanted into the left adductor muscle near the site of the excised left femoral artery (Series 2), and a stimulator (Thera, Medtronic, Inc, Minneapolis, MN) was implanted in a separate pocket. ES was applied at a rate of 3 V, 30 contractions per minute, beginning immediately after surgery and continuously for 1 month. Angiography was performed in all 12 rabbits 1 month after surgery to establish the anatomy of the collateral vessels and to demonstrate that the femoral artery stump continued to be an end artery. Contrast-opacified arteries (COAs) that crossed the grid's midline, and the total number of grid lines intersected by COAs, were tallied according to an established method. Capillary density was calculated as the number of capillaries per square millimeter of muscle. In Series 1, after 1 month, the number of COAs crossing the grid's midline was 4.5 +/-1.5 on the left and 4.8 +/-1.2 on the right side. In Series 2, the number of COAs crossing the grid's midline was 7.9 +/-1.8 on the left side (p<0.05 vs Series 1) and 5.9 +/-1.6 on the right side of the same rabbit (p=NS vs Series 1). In Series 1, 36.7 +/-5.4 and 30.5 +/-7.7 total intersections were crossed by COAs on the left and right sides, respectively. In Series 2, total grid intersections crossed by COAs were 48.4 +/-8.5 and 47.5 +/-9.1 in the left and right sides, respectively (p<0.001 vs series 1). Baseline capillary density before femoral artery excision was 180.2 +/-21.3/mm(2). The capillary densities on the left sides were 94.2 +/-19.1 and 264.5 +/-7.6 in Series 1 and 2, respectively (p<0.001). The right sides showed a similar pattern with capillary densities of 88.5 +/-37.2 and 135.8 +/-6.8 (p<0.05) in Series 1 and 2, respectively. When capillary density was compared on the left and right sides of the same rabbit in Series 2, a statistically significant increase was also found; 264.5 +/-7.6 vs 135.8 +/-6.8 (p<0.001) in the left and right sides, respectively. Comparisons of the effect of electrical stimulation and the body's normal physiologic response to acute ischemia revealed a significant increase in the opening of preexisting collaterals (arteriogenesis) and the promotion of capillary density (angiogenesis) with the use of electrical stimulation.

Validation of a left atrial lesion pattern for intraoperative ablation of atrial fibrillation.

BACKGROUND: Evidence that atrial fibrillation may begin in early stages from triggers or reentry circuits primarily in the left atrium suggests that the entire Maze 3 lesion pattern may be unnecessary. In the present study we describe a new left atrial lesion pattern for intraoperative linear ablation of chronic atrial fibrillation. METHODS: Endocardial radiofrequency ablation was performed on 12 dogs with chronic atrial fibrillation. Lesions to isolate pulmonary veins in pairs, the left atrial appendage, and connecting lesions between these structures were administered in a randomized approach. RESULTS: Twelve dogs were in chronic atrial fibrillation for 31 +/- 21 days before ablation. Atrial fibrillation was successfully ablated and rendered noninducible in all 12 dogs. All treatment failures observed with less than the full lesion pattern became a success when the remaining lesions were given. CONCLUSIONS: Atrial fibrillation ablation using this left atrial lesion pattern is highly successful in this model. This approach may have significant utility as a concomitant procedure for patients with atrial fibrillation undergoing mitral valve procedures.

Electrical stimulation promotes angiogenesis in a rabbit hind-limb ischemia model.

In previous investigations, it was shown that applying a modest regimen of electrical stimulation (ES), even in severely ischemic tissue, improves the healing process, accelerates neovascularization, and enhances angiogenesis in muscle tissue. Our objective in this current report was to further understand ES as a potential alternative treatment for severe muscle ischemia. Immediately after the left distal external iliac artery and the femoral artery were excised, ES (30 contractions per minute [cpm], 2 V, single impulses per burst) was applied to rabbit adductor muscle near the site of the excised femoralis artery for 24 hours daily over 1 month. Three other series served as controls: ES without arterial excision; arterial excision without ES or lead implantation; and arterial excision with lead implantation but no ES. Histologic study of capillary density was performed by angiography (employing a grid template) and by measuring the lower limb-calf blood pressure ratio. At the end of 30 days in the ES series, 10.5 +/-1.2 contrast-medium opacified arteries (COAs) crossed a specific grid section segment compared with 7.2 +/-1.5 in the control series without ES (p<0.05); 68.2 +/-9.3 COAs crossed a grid section compared with 43.2 +/-6.4 in controls (p<0.05); 27.3 +/-1.2 grids contained COAs compared with 29.3 +/-3.5 in controls (p<0.05); lower limb-calf blood pressure ratio was 0.81 +/-0.06 compared with 0.31 +/-0.07 in controls (p<0.05); and capillary density was 283.7 +/-24.5 mm2 compared with 91.4 +/-20.9 mm2 in controls (p<0.001). These preliminary results show that cautious ES enhances and accelerates muscle revascularization in severely ischemic tissue.

Left Atrial Anatomy in Patients Undergoing Ablation for Atrial Fibrillation.

Background: Left atrial anatomy is highly variable, asymmetric, irregular and three-dimensionally unique. This variability can affect the outcome of atrial ablation. A catalog of anatomic varieties may aid patient selection and ablation approach and provide better tools for left atrial ablation. Methods: We analyzed computed tomography scans from 514 patients undergoing left atrial ablation. Images were processed on Advantage Windows with CardEP™ software (GE Healthcare, Waukesha, WI). Measurements of pulmonary vein (PV) ostial size along the long and short axes were made using double oblique cuts, and area of the ostia was calculated. Results: Patients with 2 left (LPV) and 2 right PVs (RPV) (62.6%), 2 LPVs and 3 RPVs (17.3%) and 1 LPV and 2 RPVs (14.2%) made up the three most common variants. In the 2-LPV/2-RPV anatomy, the ostial size and area of the RPVs were larger than their corresponding LPVs (p<0.001), and the ostial size and area of the superior PVs were larger than their corresponding inferior PVs (p<0.001). In the 2-LPV/3-RPV anatomy, the total area of the RPVs was larger than the total area of the LPVs (p<0.001). In the 1-LPV/2-RPV anatomy, the ostial size of the left common PV was larger than either right PV (p<0.007). However, the total area of the RPVs was larger than the area of the left common PV (p<0.002). The left common PV was also larger than any of the left veins in any of the other anatomies. The total PV area between the three most common anatomies was not significantly different. Conclusions: More than 37% of patients have a left atrial anatomy other than 2 left and 2 right PVs. This data may help in designing approaches for left atrial ablation, tailoring the procedure to individual patients and improving ablation tools.

Cardiac Image Registration: Rotational Error Correction and Gated Stabilization for Cardiac Motion.

Background: Dynamic motion of the heart due to cardiac and respiratory cycles, and rotation from varying patient positions between imaging modalities, can cause errors during cardiac image registration. This study used phantom, patient and animal models to assess and correct these errors. Methods and Results: Rotational errors were identified and corrected using different phantom orientations. ECG-gated fluoro images were aligned with similarly gated CT images in 9 patients, and accuracy assessed during atrial fibrillation (AF) and sinus rhythm. A tracking algorithm corrected errors due to respiration; 4 independent observers compared 25 respiration sequences to an automated method. Following correction of these errors, target registration error was assessed. At 20 mm and 30 mm from the phantom model's center point with an in-plane rotation of 8 degrees, measured error was 2.94 mm and 5.60 mm, respectively, and the main error identified. A priori method accurately predicted ECG location in only 38% (p=0.0003) of 313 R-R intervals in AF. A posteriori method accurately gated the ECG during AF and sinus rhythm in 97% and 98% of 375 beats evaluated, respectively (p=NS). Tracking algorithm for ECG-gated motion compensation was identified as good or fair 96% of the time, with no difference between observers and automated method (chi-square=25; p=NS). Target registration error in phantom and animal models was 1.75±1.03 mm and 0 to 0.5 mm, respectively. Conclusions: Errors during cardiac image registration can be identified and corrected. Cardiac image stabilization can be achieved using ECG gating and respiration.

Ex vivo and in vivo regulation of lipocalin-2, a novel adipokine, by insulin.

OBJECTIVE: Lipocalin-2, a novel adipokine, has been shown to be elevated in obese, insulin-resistant, and diabetic subjects. We therefore sought to study the ex vivo and in vivo effects of insulin on lipocalin-2 levels in humans. RESEARCH DESIGN AND METHODS: We investigated the in vivo effects of insulin (hyperinsulinemia) on circulating lipocalin-2 levels by enzyme-linked immunosorbent assay via a prolonged insulin-glucose infusion. The ex vivo effect of insulin on adipose tissue lipocalin-2 protein production and secretion into conditioned media was assessed by Western blotting and enzyme-linked immunosorbent assay, respectively. RESULTS: Hyperinsulinemic induction in human subjects significantly increased circulating lipocalin-2 levels (P < 0.01). Also, in omental adipose tissue explants, insulin caused a significant dose-dependent increase in lipocalin-2 protein production and secretion into conditioned media (P < 0.05, P < 0.01, respectively); these effects were negated by both phosphatidylinositol 3-kinase and mitogen-activated protein kinase kinase inhibitors. CONCLUSIONS: Lipocalin-2 is upregulated by insulin via phosphatidylinositol 3-kinase and mitogen-activated protein kinase signaling pathways.

Autonomic ganglionated plexi: characterization and effect of epicardial microwave ablation in a canine model of vagally induced acute atrial fibrillation.

OBJECTIVE: : Autonomic ganglionated plexi (GP) in fat pads near the pulmonary veins may contribute to initiation and maintenance atrial fibrillation (AF). We attempted to localize these plexi in a canine model, and evaluate the efficacy of microwave ablation in eliminating their vagal reflexes. METHODS: : 8 Mongrel dogs (25-31 kg), underwent cervical vagal trunk stimulation to produce AV nodal block and sustained AF. Sternotomy was performed and the epicardial fat on the posterior left atrium and pulmonary veins was locally stimulated at high-frequency (20 Hz, 3-5 mA). Locations that produced a vagal response were identified and in 7 dogs ablated using the Flex 4 epicardial microwave ablation probe (Guidant Corp) at 65 watts/90 sec. One animal was a control and not ablated. Vagal responses were retested with local stimulation as well as stimulation of the cervical vagal trunks. The presence of AV block and duration of sustained AF was recorded. RESULTS: : Baseline cervical vagal stimulation produced AV block and AF in all the animals. Local high-frequency stimulation (HFS) elicited vagal responses at the junction of the inferior vena cava and the middle pulmonary vein (IVC-MPV) in 8 animals, the base of the left pulmonary veins/ligament of Marshall (LoM) in 5 animals, and between the upper and lower right pulmonary veins (RPV) in 2 animals. Microwave ablation at the IVC-MPV eliminated the vagal response upon local fat pad HFS. Cervical vagal trunk stimulation yielded less AV block (n = 2) or no AV block (n = 5) after microwave ablation of the IVC-MPV alone (n = 4) or in conjunction with LoM area ablation (n = 3). The average duration of AF during cervical vagal stimulation decreased significantly from baseline (52.7 ± 27.0 sec) versus after fat pad ablation (13.8 ± 20.3 sec, p = 0.004). CONCLUSIONS: : In a canine model we found the primary epicardial autonomic ganglionated plexi to be at the junction of the IVC-MPV. Epicardial microwave ablation of this GP eliminated the vagal response during local fat pad stimulation; and attenuated or eliminated AV block and induction of sustained AF during cervical vagal trunk stimulation. Epicardial microwave ablation of the ganglionated plexi in epicardial fat pads is feasible and can eliminate vagal reflexes that maybe important in atrial fibrillation.

Deferoxamine-fibrin accelerates angiogenesis in a rabbit model of peripheral ischemia.

The intramuscular (i.m.) injection of a modified fibrin meshwork plus deferoxamine was tested in a rabbit model of acute hind-limb ischemia. After excision of the left external iliac and femoral arteries, 12 rabbits at the Milwaukee Heart Institute were divided into two groups: control and fibrin meshwork plus deferoxamine (FDEF) i.m. The rabbits underwent angiography before surgery, immediately after, and 1 month postoperatively. These data were compiled through counting by means of a grid overlay. Another 12 rabbits at the Vakhidov Center of Surgery, which did not undergo angiography, underwent lower limb-calf blood pressure (L-CBP) measurements made immediately after surgery and at postoperative days 10, 20 and 30. Biopsies from thigh skeletal muscles of rabbits that had L-CBP measurements underwent alkaline phosphatase staining on day 30 to determine the percentage of biopsied area that was occupied by capillaries. The number of arteries and arterioles crossing 71 grid intersections immediately post-surgery decreased from 30.2 +/- 2.3 to 18.0 +/- 2.0 (p < 0.05). One month postsurgery this number increased to 29.2 +/- 2.4 in controls (p < 0.05 vs immediately post-surgery) and to 59.6 +/- 3.2 in the FDEF group (p < 0.001 vs immediately post-surgery). By day 30 the L-CBP ratio improved in the FDEF group (0.8 +/- 0.02) vs controls (0.3 +/- 0.04). By day 30 the capillary density increased from that of normal muscle tissue (198.6 +/- 12.9/mm2) to 292 +/- 12.4/mm2 in the FDEF group (p < 0.05), but decreased in the control group to 98.7 +/- 7.7/mm2. I.m. injection of FDEF considerably accelerated angiogenesis in severely ischemic hind-limb tissue in this model, making it a viable treatment method for clinical use in patients who have critical limb ischemia.