Moving average and standard deviation thresholding (MAST): a novel algorithm for accurate R-wave detection in the murine electrocardiogram.

Advances in implantable radio-telemetry or diverse biologging devices capable of acquiring high-resolution ambulatory electrocardiogram (ECG) or heart rate recordings facilitate comparative physiological investigations by enabling detailed analysis of cardiopulmonary phenotypes and responses in vivo. Two priorities guiding the meaningful adoption of such technologies are: (1) automation, to streamline and standardize large dataset analysis, and (2) flexibility in quality-control. The latter is especially relevant when considering the tendency of some fully automated software solutions to significantly underestimate heart rate when raw signals contain high-amplitude noise. We present herein moving average and standard deviation thresholding (MAST), a novel, open-access algorithm developed to perform automated, accurate, and noise-robust single-channel R-wave detection from ECG obtained in chronically instrumented mice. MAST additionally and automatically excludes and annotates segments where R-wave detection is not possible due to artefact levels exceeding signal levels. Customizable settings (e.g. window width of moving average) allow for MAST to be scaled for use in non-murine species. Two expert reviewers compared MAST's performance (true/false positive and false negative detections) with that of a commercial ECG analysis program. Both approaches were applied blindly to the same random selection of 270 3-min ECG recordings from a dataset containing varying amounts of signal artefact. MAST exhibited roughly one quarter the error rate of the commercial software and accurately detected R-waves with greater consistency and virtually no false positives (sensitivity, Se: 98.48% ± 4.32% vs. 94.59% ± 17.52%, positive predictivity, +P: 99.99% ± 0.06% vs. 99.57% ± 3.91%, P < 0.001 and P = 0.0274 respectively, Wilcoxon signed rank; values are mean ± SD). Our novel, open-access approach for automated single-channel R-wave detection enables investigators to study murine heart rate indices with greater accuracy and less effort. It also provides a foundational code for translation to other mammals, ectothermic vertebrates, and birds.

Surgical Treatment and Visual Outcomes of Adult Orbital Roof Fractures.

BACKGROUND: Fractures of the orbital roof require high-energy trauma and have been linked to high rates of neurologic and ocular complications. However, there is a paucity of literature exploring the association between injury, management, and visual prognosis. METHODS: The authors performed a 3-year retrospective review of orbital roof fracture admissions to a Level I trauma center. Fracture displacement, comminution, and frontobasal type were ascertained from computed tomographic images. Pretreatment characteristics of operative orbital roof fractures were compared to those of nonoperative fractures. Risk factors for ophthalmologic complications were assessed using univariable/multivariable regression analyses. RESULTS: In total, 225 patients fulfilled the inclusion criteria. Fractures were most commonly nondisplaced [n = 118 (52.4 percent)] and/or of type II frontobasal pattern (linear vault involving) [n = 100 (48.5 percent)]. Eight patients underwent open reduction and internal fixation of their orbital roof fractures (14.0 percent of displaced fractures). All repairs took place within 10 days from injury. Traumatic optic neuropathy [n = 19 (12.3 percent)] and retrobulbar hematoma [n = 11 (7.1 percent)] were the most common ophthalmologic complications, and led to long-term visual impairment in 51.6 percent of cases. CONCLUSIONS: Most orbital roof fractures can be managed conservatively, with no patients in this cohort incurring long-term fracture-related complications or returning for secondary treatment. Early fracture treatment is safe and may be beneficial in patients with vertical dysmotility, globe malposition, and/or a defect surface area larger than 4 cm2. Ophthalmologic prognosis is generally favorable; however, traumatic optic neuropathy is major cause of worse visual outcome in this population. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Panniculectomy at the time of bariatric surgery: a propensity score-matched analysis of outcomes in the MBSAQIP database.

BACKGROUND: Body contouring in the postbariatric surgery patient improves quality of life and daily function. OBJECTIVES: To determine the risk profile of panniculectomy when performed in select patients at the time of bariatric surgery. SETTING: Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) participating centers. METHODS: We examined the MBSAQIP database (2016-2017), in which data on 379,544 bariatric surgeries are reported. Concurrent panniculectomy procedures were identified by Current Procedural Technology (CPT) codes. Patient characteristics and in-hospital as well as 30-day complications were compared between the body contouring group and propensity score-matched bariatric surgery controls. RESULTS: One hundred twenty-four patients met inclusion criteria and were matched to 248 controls. An infra-umbilical panniculectomy was performed in the majority of patients (n = 94, 75.8%). Most patients received an open rather than laparoscopic bariatric surgery (n = 87, 70.2%). There were no statistically significant differences between 30-day mortality (1.9%), wound complications (11.5%), readmission (12.5%) and reoperation (5.8%) between the 2 groups (P > .05). Wound complications occurred in 11.5% of patients and were associated with prolonged hospital stay (odds ratio 4.65, 95% confidence interval 1.99-10.86, P < .001) and a body mass index (BMI) > 50 (odds ratio 3.19, 95% confidence interval 1.02-9.96, P = .046). CONCLUSION: In select patients, panniculectomy at the time of bariatric surgery was not associated with increased in-hospital or 30-day adverse outcomes compared with matched bariatric surgery controls. This procedure may be performed in select patients, with awareness that revision surgery may be needed once weight loss stabilizes.

The Prevalence of Blood-Borne Pathogens in Maxillofacial Trauma Patients.

BACKGROUND: Blood-borne pathogen infections (BPIs), caused by the human immunodeficiency virus, hepatitis C and hepatitis B viruses pose an occupational hazard to healthcare workers. Facial trauma reconstruction surgeons may be at elevated risk because of routine use of sharps, and a higher than average incidence of BPIs in the trauma patient population. METHODS: The authors retrospectively reviewed health records of patients admitted to a level 1 trauma center with a facial fracture between January 2010 and December 2015. Patient demographics, medical history, mechanism of injury, type of fracture, and procedures performed were documented. The authors detemined the frequency of human immunodeficiency virus, hepatitis B, and hepatitis C diagnosis and utilized univariable/multivariable analyses to identify risk factors associated with infection in this population. RESULTS: In total, 4608 consecutive patients were included. Infections were found in 4.8% (n = 219) of patients (human immunodeficiency virus 1.6%, hepatitis C 3.3%, hepatitis B 0.8%). 76.3% of BPI patients in this cohort were identified by medical history, while 23.7% were diagnosed by serology following initiation of care. 39.0% of all patients received surgical treatment during initial hospitalization, of whom 4.3% had a diagnosed BPI. History of intravenous drug use (odds ratio [OR] 6.79, P < 0.001), assault-related injury (OR 1.61, P = 0.003), positive toxicology screen (OR 1.56, P = 0.004), and male gender (OR 1.53, P = 0.037) were significantly associated with a BPI diagnosis. CONCLUSION: Patients presenting with facial fractures commonly harbor a BPI. The benefit of early diagnosis and risk to surgical staff may justify routine screening for BPI in high risk facial trauma patients (male, assault-related injury, and history of intravenous drug use).

Differences in Facial Fracture Patterns in Pediatric Nonaccidental Trauma.

BACKGROUND: The purpose of this study was to characterize differences in facial fracture injury patterns among pediatric patients at highest risk of abusive head trauma/nonaccidental trauma (age ≤ 5 years). METHODS: Using the National Trauma Databank from 2007 to 2015, patients (age ≤ 5 years) suffering facial fractures were included. Demographics and injury characteristics were compared between those sustaining accidental versus nonaccidental trauma (NAT). RESULTS: Over 9 years 9741 patients were included with 193 patients (2.0%) suffering NAT. Nonaccidental trauma patients were younger (median [interquartile range]; 0 [0, 2] versus 3 [1, 4], P < 0.001), and more frequently were insured by Medicaid (76.7% versus 41.9%, P < 0.001). NAT patients were more likely to sustain mandible fractures (38.9% versus 21.1%, P < 0.001), but less likely to sustain maxilla (9.8% versus 18.3%, P = 0.003), or orbital fractures (31.1% versus 53.4%, P < 0.001). Nonaccidental trauma patients had fewer instances of multiple facial fracture sites (8.9% versus 22.6%, P < 0.001). Among those sustaining mandible fractures, NAT patients were more likely to sustain condylar fractures (75.8% versus 48.4%, P < 0.001), but less likely to sustain subcondylar fractures (0% versus 13.2%, P = 0.002), or angle fractures (1.6 versus 8.7%, P = 0.048). CONCLUSIONS: Differences exist in facial fracture patterns in accidental versus nonaccidental trauma within the pediatric population at highest risk for abusive head trauma. Specifically, NAT is associated with fractures of the mandibular condyle and involve fewer facial fracture sites. In the appropriate context, presence of these fractures/patterns should increase suspicion for NAT.

Teamwork Makes the Dream Work: Maximizing Surgical Intervention at the Time of Living Donor Renal Transplantation.

BACKGROUND: Patients with obesity and end-stage renal disease represent a surgical population with multiple comorbidities and high risk for postoperative complications. One method for reducing the incidence of postoperative adverse events in this patient population is to limit the number of operations through combining operations into 1 operative encounter. METHODS: We conducted a retrospective review of adult patients at a single institution who underwent renal transplant, panniculectomy, and at least 1 additional abdominal or pelvic surgery concurrently. For those patients, we collected demographics, intraoperative variables, and postoperative data and analyzed surgical outcomes and postoperative complications. RESULTS: Thirteen patients met inclusion criteria. Most of the patients were female (85%) with ages ranging 33 to 70 years old and mean body mass index of 36.5 (SD 4.7). Three quarters of patients (77%) underwent 3 procedures and the remaining underwent 4 or 5 procedures with a median hospital length of stay of 5 days (range, 3-10 days). There was a single mortality. Overall, 8 patients (61.5%) experienced complications in the first 90 postoperative days. The wound complication rate was 46.2%, the overall readmission rate within 90 days was 38.5%, and the reoperation rate was 30.8%. All patients experienced immediate graft function, and the 12 patients that survived to postoperative day 90 maintained survival at 1 year. CONCLUSION: This study demonstrates that the combination of more than 2 surgical procedures with living donor renal transplant is a possible treatment option in high-risk obese patients in need of multiple operations.

Insurance Coverage Criteria for Bariatric Surgery: A Survey of Policies.

BACKGROUND: Bariatric surgery remains underutilized at a national scale, and insurance company reimbursement is an important determinant of access to these procedures. We examined the current state of coverage criteria for bariatric surgery set by private insurance companies. METHODS: We surveyed medical policies of the 64 highest market share health insurance providers in the USA. ASMBS guidelines and the CMS criteria for pre-bariatric evaluation were used to collect private insurer coverage criteria, which included procedures covered, age, BMI, co-morbidities, medical weight management program (MWM), psychosocial evaluation, and a center of excellence designation. We derive a comprehensive checklist for pre-bariatric patient evaluation. RESULTS: Sixty-one companies (95%) had defined pre-authorization policies. All policies covered the RYGB, and 57 (93%) covered the LAGB or the SG. Procedures had coverage limited to center of excellence in 43% of policies (n = 26). A total of 92% required a BMI of 40 or above or of 35 or above with a co-morbidity; however, 43% (n = 23) of policies covering adolescents (n = 36) had a higher BMI requirement of 40 or above with a co-morbidity. Additional evaluation was required in the majority of policies (MWM 87%, psychosocial evaluation 75%). Revision procedures were covered in 79% (n = 48) of policies. Reimbursement of a second bariatric procedure for failure of weight loss was less frequently found (n = 41, 67%). CONCLUSIONS: A majority of private insurers still require a supervised medical weight management program prior to approval, and most will not cover adolescent bariatric surgery unless certain criteria, which are not supported by current evidence, are met.

Sir Harold Delf Gillies-The Surgeon Artist.

Harold Gillies, a plastic surgeon who created the discipline of plastic surgery and trained hundreds of young surgeons, was foremost an artist. In a short historical perspective, we illustrate this facet of the Gillies' life through a friendship with the British ecologist William Sladen and a painting that Gillies drew during their encounters.

Characterization of Age-Related Injury Patterns and Surgical Treatment of Pediatric Facial Fractures: Analysis of the National Trauma Data Bank.

BACKGROUND: Presentation of pediatric facial fractures varies widely and many injuries are encountered infrequently by most practitioners. This study summarizes injury patterns in a large cohort of facial fractures and their subsequent surgical management. METHODS: Demographic and clinical characteristics of patients 18 years of age or younger admitted between 2009 and 2015 to trauma centers participating in the National Trauma Data Bank were examined. Craniofacial fractures and reconstructive procedures performed at index admission were selected based on ICD-9 and AIS codes. A multivariable analysis was used to determine independent determinants of surgical repair. RESULTS: Out of 60,094 pediatric patients evaluated in the US emergency departments, 48,821 patients were admitted and underwent open treatment (n = 8364; 17.1%) or closed treatment (n = 4244; 8.7%) of facial fractures. Falls were the most common mechanism of injury in infants and toddlers (<2-year-old, 44.4%, P <0.001), while motor vehicle collisions (32.9%, P <0.001) and assault (22.1%, P <0.001) were most commonly seen in adolescents (12-18-year-old). The frequency and odds of repair of facial fractures increased with advancing age, more so with open than closed treatment in adolescents (73.0%) as compared to infants and toddlers (50.3%). Children who sustained mandible fractures are the most likely to require surgical treatment at index-admission (odds ratio = 13.9, 95% confidence interval 13.1-14.8, P <0.001). CONCLUSIONS: Population-based data shows that pediatric fracture patterns and associated early repair vary significantly with age. Patient demographics and hospital characteristics are significant determinants of surgical treatment that should be related to clinical outcomes in future studies.

Contemporary Characterization of Injury Patterns, Initial Management, and Disparities in Treatment of Facial Fractures Using the National Trauma Data Bank.

BACKGROUND: Contemporary description of facial fracture patterns and factors associated with early operative intervention at trauma centers is lacking. The purpose of this study was to characterize injuries and initial treatment patterns of patients suffering from facial fractures. METHODS: Using the National Trauma Databank from 2007 to 2015, patients suffering from facial fractures were included. Demographics, injury characteristics, and outcomes including operative interventions were assessed. RESULTS: Over 9 years, 626,270 patients were included: 74.5% were male, 39.0% suffered traumatic brain injury (TBI), and 23.3% severe noncraniofacial injuries (chest, abdomen, and/or extremity Abbreviated Injury Score ≥3). A total of 537,594 (85.8%) patients were admitted and 184,206 (34.3%) underwent operations for their facial injuries during the index hospitalization. The frequency and patterns of fractures varied by age, sex, race, and mechanism of injury. Operative intervention rates were highest for mandible (63.2%) and lowest for orbit fractures (1.0%). Multiple regression revealed that multiple factors were independently associated with the odds of early fracture repair including: female versus male (odds ratio [95% confidence interval]: 0.96 [0.94-0.98]), age >65 versus <18 years (0.62 [0.59-0.64]), non-white race (0.95 [0.94-0.97]), uninsured versus Medicaid (0.88 [0.86-0.90]), hospital bed size (>600 vs ≤200 beds, 1.67 [1.61-1.73]), TBI (0.70 [0.69-0.71]), and C-spine injury (0.93 [0.90-0.96]). CONCLUSIONS: Facial fractures are common among many demographic cohorts, and multiple patient and injury-specific factors influenced fracture patterns and management. Early operative intervention was highest for mandible fractures and lowest for orbit fractures. Multiple factors including age, sex, insurance status, hospital characteristics, and race/ethnicity were independently associated with early operative intervention, highlighting disparities in care.

Panniculectomy at the time of living donor renal transplantation: An 8-year experience.

Panniculectomy can be performed as a prophylactic procedure preceding transplantation to enable obese patients to meet criteria for renal transplantation. No literature exists on combined renal transplant and panniculectomy surgery (LRT-PAN). We describe our 8-year experience performing LRT-PAN. A retrospective chart review of all patients who had undergone LRT-PAN from 2010 to 2018 was conducted. Data were collected on patient demographics, allograft survival and function, and postoperative course. Fifty-eight patients underwent LRT-PAN. All grafts survived, with acceptable function at 1 year. Median length of stay was 4 days with a mean operative duration of 363 minutes. The wound complication rate was 24%. Ninety-day readmission rate was 52%, with medical causes as the most common reason for readmission (45%), followed by wound (32%) and graft-related complications (23%). Body mass index, diabetes status, and previous immunosuppression did not influence wound complication rate or readmission (P = .7720, P = .0818, and P = .4830, respectively). Combining living donor renal transplant and panniculectomy using a multidisciplinary team may improve access to transplantation, particularly for the obese and postobese population. This combined approach yielded shorter-than-expected hospital stays and similar wound complication rates, and thus should be considered for patients in whom transplantation might otherwise be withheld on the basis of obesity.

Improved electromagnetic tracking for catheter path reconstruction with application in high-dose-rate brachytherapy.

PURPOSE: Electromagnetic (EM) catheter tracking has recently been introduced in order to enable prompt and uncomplicated reconstruction of catheter paths in various clinical interventions. However, EM tracking is prone to measurement errors which can compromise the outcome of the procedure. Minimizing catheter tracking errors is therefore paramount to improve the path reconstruction accuracy. METHODS: An extended Kalman filter (EKF) was employed to combine the nonlinear kinematic model of an EM sensor inside the catheter, with both its position and orientation measurements. The formulation of the kinematic model was based on the nonholonomic motion constraints of the EM sensor inside the catheter. Experimental verification was carried out in a clinical HDR suite. Ten catheters were inserted with mean curvatures varying from 0 to [Formula: see text] in a phantom. A miniaturized Ascension (Burlington, Vermont, USA) trakSTAR EM sensor (model 55) was threaded within each catheter at various speeds ranging from 7.4 to [Formula: see text]. The nonholonomic EKF was applied on the tracking data in order to statistically improve the EM tracking accuracy. A sample reconstruction error was defined at each point as the Euclidean distance between the estimated EM measurement and its corresponding ground truth. A path reconstruction accuracy was defined as the root mean square of the sample reconstruction errors, while the path reconstruction precision was defined as the standard deviation of these sample reconstruction errors. The impacts of sensor velocity and path curvature on the nonholonomic EKF method were determined. Finally, the nonholonomic EKF catheter path reconstructions were compared with the reconstructions provided by the manufacturer's filters under default settings, namely the AC wide notch and the DC adaptive filter. RESULTS: With a path reconstruction accuracy of 1.9 mm, the nonholonomic EKF surpassed the performance of the manufacturer's filters (2.4 mm) by 21% and the raw EM measurements (3.5 mm) by 46%. Similarly, with a path reconstruction precision of 0.8 mm, the nonholonomic EKF surpassed the performance of the manufacturer's filters (1.0 mm) by 20% and the raw EM measurements (1.7 mm) by 53%. Path reconstruction accuracies did not follow an apparent trend when varying the path curvature and sensor velocity; instead, reconstruction accuracies were predominantly impacted by the position of the EM field transmitter ([Formula: see text]). CONCLUSION: The advanced nonholonomic EKF is effective in reducing EM measurement errors when reconstructing catheter paths, is robust to path curvature and sensor speed, and runs in real time. Our approach is promising for a plurality of clinical procedures requiring catheter reconstructions, such as cardiovascular interventions, pulmonary applications (Bender et al. in medical image computing and computer-assisted intervention-MICCAI 99. Springer, Berlin, pp 981-989, 1999), and brachytherapy.

Helicobacter pylori Infection among Patients with Dyspepsia and Intrafamilial Transmission.

INTRODUCTION: Recurrence is an important problem after Helicobacter pylori infection, and intrafamilial transmission has an important role in recurrence. In this study, we aimed to investigate the significance of intrafamilial transmission for recurrence development after treatment as well as its usefulness in prevention. MATERIALS AND METHODS: Of the 109 patients who had dyspepsia and underwent endoscopy, 74 patients had H. pylori infection and were enrolled in this study. Infected family members were also detected. Patients were randomly divided into groups I and II, with each group containing 37 individuals. In group I, patients and their infected family members were treated together at the same time. In group II, only the patients were treated. Treatment success was evaluated at the 1st month and evaluation for recurrence was carried out at the 6th month. RESULTS: Helicobacter pylori infection was detected in 67.8% of the patients with dyspepsia. Two patients in each group did not show up at the 1st month control. Eradication was achieved in 63 of the 70 patients (90.0%) who completed their treatment. After 6 months, patients with successful treatment had no recurrence in any of the 32 patients in group I. There were recurrence in 3 of the 31 patients (9.7%) in group II; however, there was no statistically significant difference between the groups (p = 0.113). CONCLUSION: Our study showed that eradication treatment in patients and family members with H. pylori infection resulted in a decrease in the number of recurrences even though it was not statistically significant. HOW TO CITE THIS ARTICLE: Yalçin M, Yalçin A, Bengi G, Nak SG. Helicobacter pylori Infection among Patients with Dyspepsia and Intrafamilial Transmission. Euroasian J Hepato-Gastroenterol 2016;6(2):93-96.

AST/ALT ratio is not useful in predicting the degree of fibrosis in chronic viral hepatitis patients.

BACKGROUND AND AIM: Noninvasive tests are primarily used for staging hepatic fibrosis in patients with chronic liver disease. In clinical practice, serum aminotransferase levels, coagulation parameters, and platelet count have been used to predict whether or not a patient has cirrhosis. In addition, several studies have evaluated the accuracy of combinations (or ratios) of these measures. The present study aimed to investigate the relationship between five noninvasive models [AST/ALT ratio (AAR), aspartate aminotransferase to platelet ratio index (APRI), Bonacini cirrhosis discriminant score (CDS), age-platelet index (APind), and King's score] and the degree of hepatic fibrosis as determined by biopsy in patients with chronic hepatitis B and C. PATIENTS AND METHODS: A total of 380 patients with viral hepatitis (237 with chronic hepatitis B and 143 with chronic hepatitis C) who were seen at our clinic between January 2005 and January 2011 were retrospectively analyzed. The degree of fibrosis was determined using the Ishak score. Patients with a fibrosis score of 0-2 were considered to have low fibrosis and those with a score between 3 and 6 were considered to have high fibrosis. Five noninvasive models were compared between the groups with low and high fibrosis. RESULTS: There were statistically significant differences between the hepatitis B and C patients with high and low fibrosis with respect to APind (4.49±2.35 vs. 2.41±1.84; P<0.001 in hepatitis B and 4.83±2.25 vs. 2.92±1.88; P<0.001 in hepatitis C), APRI (1.00±1.17 vs. 0.47±0.39; P<0.001 in hepatitis B and 1.01±1.01 vs. 0.41±0.29; P<0.001 in hepatitis C), CDS (4.53±1.90 vs. 3.58±1.30; P<0.001 in hepatitis B and 4.71±2.03 vs. 3.42±1.49; P<0.05 in hepatitis C), and King's score (24.31±3.14 vs. 7.65±6.70; P<0.001 in hepatitis B and 24.82±2.55 vs. 8.33±7.29; P<0.001 in hepatitis C). There were no significant differences in the AAR between the hepatitis B and C patients with high and low fibrosis (0.78±0.31 vs. 0.74±0.34; P=0.082 in hepatitis B and 0.91±0.40 vs. 0.85±0.27; P=0.25 in hepatitis C). The area under the receiver-operating characteristic curve of the APind, APRI, CDS, and King's score in the hepatitis B group were 0.767, 0.710, 0.646, and 0.770, respectively; these values were 0.732, 0.763, 0.677, and 0.783, respectively, in the hepatitis C group. CONCLUSION: In conclusion, our data suggest that four of the five noninvasive methods evaluated in this study can be used to predict advanced fibrosis in patients with hepatitis B and C. However, there was no significant relationship between the degree of hepatic fibrosis and the AAR score, indicating that AAR is not useful in estimating the fibrosis stage in hepatitis B and C patients.

Electromagnetic tracking in surgical and interventional environments: usability study.

PURPOSE: Electromagnetic (EM) tracking of instruments within a clinical setting is notorious for fluctuating measurement performance. Position location measurement uncertainty of an EM system was characterized in various environments, including control, clinical, cone beam computed tomography (CBCT), and CT scanner environments. Static and dynamic effects of CBCT and CT scanning on EM tracking were evaluated. METHODS: Two guidance devices were designed to solely translate or rotate the sensor in a non-interfering fit to decouple pose-dependent tracking uncertainties. These devices were mounted on a base to allow consistent and repeatable tests when changing environments. Using this method, position and orientation measurement accuracies, precision, and 95 % confidence intervals were assessed. RESULTS: The tracking performance varied significantly as a function of the environment-especially within the CBCT and CT scanners-and sensor pose. In fact, at a fixed sensor position in the clinical environment, the measurement error varied from 0.2 to 2.2 mm depending on sensor orientations. Improved accuracies were observed along the vertical axis of the field generator. Calibration of the measurements improved tracking performance in the CT environment by 50-85 %. CONCLUSION: EM tracking can provide effective assistance to surgeons or interventional radiologists during procedures performed in a clinical or CBCT environment. Applications in the CT scanner demand precalibration to provide acceptable performance.

Heart rate variability and procedural outcome in catheter ablation for atrial fibrillation.

INTRODUCTION: In patients with normal hearts, increased vagal tone is associated with onset of paroxysmal atrial fibrillation (AF). Vagal denervation of the atria renders AF less inducible. Circumferential pulmonary vein isolation (CPVI) is effective for treating paroxysmal and persistent AF, and has been shown to impact heart rate variability (HRV) indices, in turn, reflecting vagal denervation. We examined the impact of CPVI on HRV indices, and evaluated the relationship between vagal modification and AF recurrence. METHODS: Electrocardiogram recordings were collected from 83 consecutive patients (63 male, 20 female, age 56.9 ± 9.3 years) undergoing CPVI for paroxysmal (n = 56) or persistent (n = 27) AF. Recordings were obtained over 10 minutes preprocedure, and at intervals up to 12 months. Antiarrhythmic medications were suspended prior to CPVI, and were resumed for 3 months following. Success was defined as no recurrence of atrial arrhythmia lasting longer than 30 seconds. RESULTS: In patients with successful procedures (n = 56, 42 paroxysmal, 14 persistent), HRV indices were significantly altered, with respect to preprocedure levels, over a sustained period. However, patients with recurrence (n = 27, 14 paroxysmal, 13 persistent) demonstrated similar HRV to their preprocedure levels over the follow-up period. CONCLUSION: Our results suggest that patients experiencing recurrence after a single CPVI have HRV attenuated by the procedure only intermittently, whereas patients with one successful CPVI experience a sustained change. A short-term HRV recording is a convenient and potentially important marker for recurrence of atrial arrhythmia in a population undergoing CPVI.

Vascular access in hemodialyis patients - registry data.

BACKGROUND: The use of arteriovenous fistula over a central venous catheter in hemodialysis patients is recommended whenever possible. It has become the gold standard among all the available permanent vascular accesses for hemodialysis as it is associated with less complications. The aim of our study was to analyze the type of vascular access in hemodialysis patients in our country, FYR of Macedonia and to see its association with other variables recorded by the National Renal Registry in 2009. MATERIAL AND METHODS: Data were collected by 18 hemodialysis centers in the country. A total of 1,457 patients were analyzed. One hundred and ninety one patients were incident, and 164 out of 1,457 died during the year. Except for 9 patients, all the others had data on type of vascular access, as well as data on any vascular access intervention performed during the year. RESULTS: The overall mean age was 58.8 ± 13.1 years. Eighty-nine percent of the non-incident patients (prevalent plus those who died during the year) had arteriovenous fistula, 10.6% central venous catheter and 0.2% vascular graft. When incident to non-incident patients were compared, incident patients were significantly older, had significantly higher mortality and significantly lower percentage of arteriovenous fistula. Patients with arteriovenous fistula had significantly longer dialysis vintage and significantly less deaths compared to those with central venous catheters. CONCLUSIONS: The study showed that the number of non-incident hemodialysis patients with arteriovenous fistula in the country was high. The incident hemodialysis patients have high number of central venous catheters as vascular access for hemodialysis and significantly higher mortality compared to non-incident patients. Hippokratia 2014; 18 (3): 209-211.

Validation of a novel algorithm for quantification of the percentage of signal fractionation in atrial fibrillation.

AIMS: Catheter ablation for paroxysmal atrial fibrillation (AF) is rapidly becoming a standard practice. There is literature to support that catheter ablation of persistent AF requires additional 'substrate modification'. In clinical practice, operators rely on automated fractionation maps created by three-dimensional anatomic mapping systems to rapidly assess complex 'fractionated' signals (CFAE). These systems use differing algorithms to automate the process. The agreement between operators and contemporary algorithms has not been examined. We sought to assess the agreement between operators and a novel method of quantification calculating percentage fractionation (PF). METHODS AND RESULTS: Expert opinion on 80 atrial electrogram 4 s signals of varying levels of activity were gathered and pooled for comparison. Twelve independent experts visually quantified the signal fractionation and offered a threshold level for ablation. We developed an algorithm to find sites with high continuous electrical activity, or high PF. Correlation between experts and PF was 0.78 [P < 0.01, 95% confidence interval (CI) (0.68-0.86)]. Receiver operating characteristics curve sensitivity and specificity for PF were 0.7727 and 0.8103 at the optimal cut-off point of 58.45 PF with area under curve 0.89 CI (0.80-0.99). CONCLUSION: The PF statistic represents a more robust and intuitive measure to represent fractionated atrial activity; importantly it demonstrates excellent agreement with expert users and presents a new standard for algorithm assessment. Use of a PF statistic should be considered in automated mapping systems.

Multi-lead QRS detection using window pairs.

We designed a novel approach for multi-lead QRS detection. The algorithm uses one equation with two different window widths to generate a feature signal and a detection threshold. This enables it to adapt to various changes in QRS morphology and noise levels, resulting in a detection error rate of just 0.29% on the MIT-BIH Arrhythmia Database. The algorithm is also computationally efficient and capable of resolving differences between multiple leads by automatically attaching a confidence value to each QRS detection.

Perfil autonómico de los pacientes derivados a una clínica de trastornosdel sueño: impacto de la CPAPen el sistema nervioso autónomo / Autonomic profile of patients referred to a sleep disorder clinic: impact of CPAP on the autonomic nervous system

Introducción: la apnea obstructiva del sueño (AOS) severa ha sido asociada con disfunción autonómica. La presión positiva continua en la vía aérea (CPAP) es el tratamiento estándar para la AOS, aun cuando su impacto sobre la disfunción autonómica no haya sido plenamente investigado. La variabilidad de la frecuencia cardíaca (VFC) es una técnica cuantitativa no invasiva para la evaluación de la actividad autonómica. Nuestro objetivo fue determinar si los pacientes con AOS severa presentan niveles mayores de disfunción autonómica que los pacientes con un índice de apnea-hipopnea (IAH) normal, y si la CPAP mejora los parámetros de VFC a la vez que mejora el IAH.Métodos: todos los pacientes fueron sometidos a una polisomnografía (PSG) completa en una clínica de trastornos del sueño. Se definió como severa a una AOS que tuviera un IAH ³ 30 (eventos por hora), y se definió al grupo control como aquellos que tuvieran un IAH < 5. Se calculó la VFC antes y después de la CPAP, analizando trazados electrocardiogáficos de 10 minutos, conforme las pautas de normalización. Los pacientes con AOS severa fueron tratados con CPAP durante un período de 4-6 semanas (titulados durante la polisomnografía), y los pacientes control no recibieron ninguna intervención entre sus dos registros de electrocardiograma (ECG).Resultados: el estudio incluyó a un total de 20 pacientes con AOS severa y 10 controles. En los pacientes con AOS severa, el IAH se redujo al utilizar CPAP de 38,0 ± 11,0 a 23,0 ± 11,0 (p<0,01). Aparte de una diferencia significativa en el índice de masa corporl (IMC) entre los paciente con AOS y los controles (35,3±4,7 versus 26,6±4,6 kg/m2, p<0,01), los grupos fueron comparables en cuanto a edad, condición de hipertensión y género. No hubo ninguna diferencia significativa (p<0,05) en ningún parámetro de VFC entre los pacientes con AOS severa y los controles, ni entre los pacientes con AOS antes y después de CPAP (tabla 2).

Introduction: severe obstructive sleep apnea (OSA) has been associated with autonomic dysfunction. Continuous positive airway pressure (CPAP) is standard treatment for OSA, although its impact on autonomic dysfunction was not fully investigated. Heart rate variability (HRV) is a non-invasive quantitative technique for assessment of autonomic activity. We aimed to determine if patients with severe OSA exhibit greater levels of autonomic dysfunction than patients with normal apnea-hypopnea index (AHI), and if CPAP improves heart rate variability (HRV) parameters while improving AHI.Methods: all patients underwent full polysomnography (PSG) at a Sleep Disorder Clinic. Severe OSA was defined as AHI ³ 30 (events per hour), and control was defined as AHI < 5. HRV was calculated pre and post-CPAP from a 10-minute electrocardiogram (ECG) recording in accordance with guidelines for standardization. Patients with severe OSA were treated with CPAP for a period of 4-6 weeks (titrated during PSG), and control patients underwent no intervention between their two ECG recordings.Results: a total of 20 patients with severe OSA and 10 controls were included (Table 1). In patients with severe OSA, AHI was reduced by CPAP from 38.0 ± 11.0 to 23.0 ± 11.0 (P<0.01). Aside from a significant difference in BMI between OSA patients and controls (35.3±4.7 vs. 26.6±4.6 kg/m2, P<0.01), groups were comparable in age, hypertension, and gender. There was no significant difference (P<0.05) in any HRV parameters between patients with severe OSA and controls, and between OSA patients pre- and post-CPAP (table 2).