Impedance and conductivity of bovine myocardium during freezing and thawing at slow rates - implications for cardiac cryo-ablation

Increasing impedance during freezing might be a valuable marker for guiding cardiac cryo-ablation. We provide model based insights on how decreasing temperature below the freezing point of tissue relates to the percentage of frozen water. Furthermore, we provide experimental data for comparing this percentage with the increase in impedance. Measurements were performed on a bovine tissue sample at frequencies between 5 and 80 kHz. Slow cooling and heating rates were applied to minimize temperature gradients in the myocardial sample and to allow accurate assessment of the freezing point. Computer simulation was applied to link impedance with temperature dependent conductivities. The osmotic virial equation was used to estimate the percentage of frozen water. Measurements identified the freezing point at -0.6 ^∘C. At -5 ^∘C, impedance rose by more than a factor of ten compared to that at the freezing point and the percentage of frozen water was estimated as being 89%. At -49 ^∘C impedance had increased by up to three orders of magnitude and ice formation was most pronounced in the extracellular space. Progressive ice formation in tissue is reflected by a large increase in impedance, and impedance increases monotonically with the percentage of frozen water. Its analysis allows for experimental assessment of factors relevant to cell death. Solid ice contributes to the rupture of the micro-vasculature, while phase shifts reflect concentration differences between extra- and intracellular space driving osmotic water transfer across cell membranes.

Adult ADHD Is Associated With Gambling Severity and Psychiatric Comorbidity Among Treatment-Seeking Problem Gamblers

Objective: The aim of this study is as follows: (a) exploring retrospective childhood and adult ADHD symptomatology in treatment-seeking gamblers, (b) providing detailed characteristics of the association between pathological gambling (PG) and ADHD, and (c) identifying risk factors for a history of ADHD. Method: Eighty problem gamblers (20% female) were examined using a standardized interview (PG: Diagnostic and Statistical Manual of Mental Disorders [4th ed.; DSM-IV] criteria, Gambling Attitudes and Beliefs Survey; ADHD: Wender Utah Rating Scale-deutsche Kurzform, Adult ADHD Self-Report Scale; comorbidities: Mini International Neuropsychiatric Interview). Results: Forty-three percentage of patients screened positive for childhood ADHD, and in 11%, ADHD persisted in adulthood. Patients with adult ADHD had more severe gambling problems (p = .009, d = 1.03) and a higher number of psychiatric comorbidities (p < .001, d = 1.62) compared with those without ADHD. Substance abuse/dependence constituted a predictor for having a history of ADHD (odds ratio [OR] = 4.07, p = .025). Conclusion: ADHD-PG comorbidity is linked to factors that worsen the prognosis. Thus, screening for ADHD and verifying persistence in adulthood should be an integral component in the interdisciplinary treatment of problem/pathological gamblers.

Infecção latente pelo herpesvírus bovino tipo 1 em búfalos (Bubalus bubalis) no Rio Grande do Sul

RESUMO Apesar dos bovinos serem considerados os hospedeiros naturais do BoHV-1, estudos sorológicos têm sugerido que búfalos podem ser suscetíveis ao BoHV-1 e a outros alfa-herpesvírus geneticamente relacionados. O objetivo deste estudo foi detectar a presença de DNA viral de BoHV-1 em 202 amostras de gânglios trigêmeos de búfalos, pela técnica de semi-nested PCR, para detecção de um segmento do gene codificante da glicoproteína D (gD) do BoHV-1. Além disso, 242 amostras de soro foram analisadas pela técnica de soroneutralização (SN) para a detecção de anticorpos neutralizantes contra BoHV-1, BoHV-5 e BuHV. Todas as amostras clínicas foram coletadas em um matadouro na cidade de Pelotas, RS, Brasil. O DNA de BoHV-1 foi detectado em 61 (30,1%) gânglios, e os resultados da SN demonstraram que 27,6% dos animais apresentaram anticorpos contra, pelo menos, um dos vírus testados. O sequenciamento genômico e a análise de 14 amplicons confirmaram a presença do DNA do BoHV-1 nos tecidos analisados. Em resumo, os resultados indicam que o BoHV-1 está distribuído em rebanhos bubalinos provenientes da região Sul do Brasil. Entretanto, são necessárias investigações adicionais, no sentido de elucidar o papel exato dos búfalos na epidemiologia das infecções pelo BoHV-1.

Assessing the impact of mailing self-sampling kits for human papillomavirus testing to unscreened non-responder women in Manitoba

Background

CervixCheck, Manitoba's cervical cancer screening program, conducted a pilot study to assess whether screening participation could be improved in unscreened women by offering a mailed self-sampling kit for human papillomavirus (hpv) testing instead of a Pap test.

Methods

In a prospective cohort study design, a sample of unscreened women (n = 1052) who had been sent an invitation letter from CervixCheck in the past but who did not respond were randomized to either an intervention group or a control group. The intervention group received a mailed hpv self-sampling kit; the control group received no additional communication. Returned hpv self-sampling swabs were analyzed by a provincial laboratory. After 6 months, screening participation in the two study groups was compared using a logistic regression model adjusted for age and area of residence (urban or rural). Secondary outcomes included hpv positivity, specimen inadequacy, compliance with follow-up, and time to colposcopy.

Results

Screening participation was significantly higher in the intervention group than in the control group (n = 51, 9.6%, vs. n = 13, 2.5%; odds ratio: 4.7; 95% confidence interval: 2.56 to 8.77). Geographic area of residence (urban or rural) and age were not statistically significant.

Conclusions

The study demonstrated that hpv self-sampling kits can enhance screening participation in unscreened non-responder women in the setting of an organized screening program. Next steps should include additional research to determine the best implementation strategy for hpv self-sampling in Manitoba.

Comorbidity Patterns Among Patients With Opioid Use Disorder and Problem Gambling: ADHD Status Predicts Class Membership

Objective: Psychiatric comorbidities are highly prevalent among individuals affected by substance use disorders and those with non-substance-related addictive disorders such as gambling disorder. More recently, the frequent co-occurrence of substance use disorders and attention-deficit hyperactivity disorder (ADHD) has received particular attention. The aim of our study was to identify patterns of psychiatric comorbidity and to examine associations between patient group and ADHD status with class membership. Methods: Participants were patients with opioid use disorder enrolled in opioid maintenance treatment (OMT), either recruited from the community (n = 142; M age = 35.8 years; 38.7% female) or prison (n = 133; M age = 35.7 years; 21.8% female), and patients undergoing treatment for problem gambling (PrG; n = 80; M age = 43.1 years; 20% female). To enable direct comparisons, the following instruments were applied: Mini International Neuropsychiatric Interview, Adult ADHD self-report scale, Wender Utah Rating Scale, and European Addiction Severity Index. We used a latent class analysis (LCA) to identify psychiatric comorbidity patterns and a multinomial logistic regression to examine associations between patient group, ADHD status, age, and gender with class membership. Results: The LCA resulted in a three-class solution: (1) a class of individuals with a relatively low probability of current psychiatric comorbidities, except for a high probability of substance use disorders; (2) a class with markedly increased probabilities of current and recurrent psychiatric comorbidities, especially for major depression; and (3) a class with very low probabilities of psychiatric comorbidities, except for moderate probabilities of substance use disorders and antisocial personality disorder. Both OMT patients recruited from the community and those in prison were less likely than PrG patients to be assigned to the most burdened class with respect to psychiatric comorbidity (class 2). Further, both individuals with ADHD in childhood and those with adult ADHD were more likely members of class 2. Conclusions: PrG patients seem to be at an even higher risk for psychiatric comorbidities compared to OMT patients. Raising awareness among practitioners for the high prevalence of psychiatric comorbidities among patients with gambling disorder and individuals with ADHD is crucial to initiate adequate treatment and to improve response.

Chemical and cytotoxic analyses of three varieties of Brazilian propolis (green propolis, jataí propolis and brown propolis) and its anti-Sporothrix brasiliensis in vitro activity

ABSTRACT In this study, we described the antifungal activity of three Brazilian propolis extracts: brown, green and from jataí bees against Sporothrix brasiliensis. The extracts were obtained from ethanolic extraction and their chemical composition was determined by high-performance liquid chromatography coupled to mass spectrometry. The cellular toxicity was measured in MDBK (Madin-Darby Bovine Kidney) cells and quantified by the MTT assay (3- (4,5 dimethylthiazol-2yl -2,5-diphenyl-2H bromine tetrazolato). For antifungal activity, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined by broth microdilution. The results showed that cell toxicity was not observed at lower concentrations (0.097 to 0.39μg/ml) for all extracts in comparison to cell control. Among the chemical compounds identified, caffeic acid, p-coumaric acid, chlorogenic acid, ferulic acid and rutin were quantified. In antifungal activity, green and jataí did not exhibit activity against the isolates (MIC and MFC greater than 0.78mg/ml). However, all isolates of S. brasiliensis were sensitive to brown propolis (MIC of 0.09 to 0.78mg/ml), including the standard strain (P<0.001). Among the Brazilian propolis studied, the brown propolis showed activity against the S. brasiliensis isolates and more studies should be undertaken in order to evaluate its promising use in the treatment of sporotrichosis.

Influence of patient and tumor characteristics on early therapy persistence with letrozole in postmenopausal women with early breast cancer: results of the prospective Evaluate-TM study with 3941 patients

Background

Patients' compliance and persistence with endocrine treatment has a significant effect on the prognosis in early breast cancer (EBC). The purpose of this analysis was to identify possible reasons for non-persistence, defined as premature cessation of therapy, on the basis of patient and tumor characteristics in individuals receiving adjuvant treatment with letrozole.

Patients and methods

The EvAluate-TM study is a prospective, multicenter, noninterventional study in which treatment with the aromatase inhibitor letrozole was evaluated in postmenopausal women with hormone receptor-positive EBC in the early therapy phase. Treatment persistence was evaluated at two pre-specified study visits after 6 and 12 months. As a measure of early therapy persistence the time from the start to the end of treatment (TTEOT) was analyzed. Cox regression analyses were carried out to identify patient characteristics and tumor characteristics predicting TTEOT.

Results

Out of the total population of 3941 patients with EBC, 540 (13.7%) events involving treatment cessation unrelated to disease progression were observed. This was due to drug-related toxicity in the majority of cases (73.5%). Persistence rates were 92.2%, 86.9%, and 86.3% after 6, 12, and 15 months, respectively. The main factors influencing premature treatment discontinuation were older age [hazard ratio (HR) 1.02/year], comorbidities (HR 1.06 per comorbidity), low body mass index, and lower tumor grade (HR 0.85 per grade unit).

Conclusion

These results support the view that older, multimorbid patients with low tumor grade and low body mass index are at the greatest risk for treatment discontinuation and might benefit from compliance and support programs.

Attention-Deficit Hyperactivity Disorder Symptom Status in a Mixed Gender Population of Opioid-Maintained Prison Inmates

OBJECTIVE

Attention-deficit hyperactivity disorder (ADHD) often coincides with substance abuse and delinquency. A sample of opioid-maintained inmates was assessed for symptoms of ADHD, substance abuse history, types of offense, psychiatric comorbidities, and psychopharmacological treatment using a standardized battery of instruments.

METHOD

Adult inmates (n = 133, mean age 35.7 years, 21.8% female) in opioid-maintenance therapy (OMT) were administered the Adult ADHD self-report scale, Wender Utah Rating Scale, Mini International Neuropsychiatric Interview, -European Addiction Severity Index.

RESULTS

Fifty percent screened positive for childhood and 17% for adult ADHD, four (3.1%) received ADHD medication. Inmates with ADHD symptom status were significantly younger at first substance abuse, reported more drug overdoses, longer duration of cocaine and prescribed medication abuse and more in- and outpatient treatments (all p < 0.05). For all inmates in OMT a high rate of psychiatric comorbidities was observed (78.9%).

CONCLUSION

There is a need for assessment of ADHD and other psychiatric comorbidities in OMT prisoners. Evidence-based treatment should be routinely provided.

A Low-Power Injection-Locked VCO for an Implantable MICS Band Transmitter with Wireless Frequency Reference and Tune-while-Lock Channel Calibration

This paper presents the design of an 800 MHz VCO for both free-running and injection locked operation in a novel low power transmitter with wireless frequency reference, operating in the MICS band (402-405 MHz). The transmitter employs simultaneous tuning and locking, to set the desired channel with a minimal injected power. The VCO is designed and fabricated in a 0.13 $\mu \mathrm{m}$ SiGe BiCMOS process and has a core area of 0.5 $\mathrm{m}\mathrm{m}^{2}$. The measurement of the free-running VCO shows -107 dBc/Hz phase noise at 300 kHz frequency offset. If locked to an external frequency reference the VCO shows 118 dBc/Hz phase noise at 300 KHz offset, while consuming 3 mA from a 1.2 V supply (3.6 mW). When the VCO is tuned during the locking, 20 dBm of reference power is required to enable operation in the whole MICS band. The measured phase noise of the free-running VCO ensures reliable calibration of the proposed transmitter and the locked VCO satisfies all requirements of an implantable device using MICS band data transmission. Therefore, this VCO presents a key building block of an injection locked, frequency agile, implantable transmitter for the MICS band.

Hepatitis C infection and psychiatric burden in two imprisoned cohorts: Young offenders and opioid-maintained prisoners

Prisoners constitute a considerable gap in the hepatitis C virus (HCV) tested population. The present study examined HCV prevalence in imprisoned opioid-maintained patients (OMT-P) and adolescents and young adults (AYA, 14-26 years). In addition, HCV testing and treatment provision, knowledge of HCV status and psychiatric comorbidity were assessed. Data collection took place in six Austrian prisons. Participants were N = 133 for OMT-P (78% male, mean age 35.7 years) and N = 71 for AYA (100% male, mean age 19.8 years). Analysis of HCV serology was conducted. Psychiatric comorbidity and addiction severity were assessed applying standardized questionnaires and interviews. Antibodies were detected in 74.4% of OMT-P, and in 45.0% HCV infection was confirmed. Only one AYA was infected with HCV. None of the participants was receiving treatment for HCV. Eleven percent of OMT-P (50.7% of AYA) did not know their HCV status, and 14.3% of OMT-P (36.6% of AYA) had not been tested in prison. Among OMT-P, lifetime IDU [OR = 330.33, CI = 25.91-4433.20] and age at first IDU [OR = 0.90, CI = 0.82-0.98] significantly predicted HCV status. In both samples, a high prevalence of affective disorders was observed. Despite the high prevalence of HCV among opioid-dependent detainees, the unique opportunities for comprehensive testing and treatment of HCV are substantially underutilized. This is in stark contrast to the UN Basic Principles for the Treatment of Prisoners.

Correction to: Psychiatric comorbidity and intimate partner violence among women who inject drugs in Europe: a cross-sectional study

The original version of this article unfortunately missed the Acknowledgment.

Psychiatric comorbidity and intimate partner violence among women who inject drugs in Europe: a cross-sectional study

Women who inject drugs (WWID) are an especially vulnerable group of drug users. This study determined the prevalence of psychiatric comorbidity and intimate partrner violence (IPV), and factors associated with psychiatric comorbidity among WWID recruited from drug treatment services (67%) and harm reduction services in five European regions in Austria, Catalonia, Italy, Poland, and Scotland. Psychiatric comorbidity was assessed among 226 WWID using the Dual Diagnosis Screening Instrument. IPV was assessed using the Composite Abuse Scale and injecting and sexual risk behaviors were assessed using a battery of questionnaires adapted and developed for the study. Eighty-seven percent met criteria for at least one lifetime psychiatric disorder. The most common disorders were depression (76%), panic (54%), and post-traumatic stress (52%). WWID recruited in drug treatment services were almost three times as likely (OR 2.90 95% CI 1.30-6.43; p = 0.007) to meet criteria for a lifetime psychiatric disorder than those recruited from harm reduction services, specifically dysthymia (OR 5.32 95% CI 2.27-12.48; p = 0.000) and post-traumatic stress disorder (OR 1.83 95% CI 1.02-3.27; p = 0.040). WWID who reported sharing needles and syringes were almost three times as likely to meet criteria for lifetime psychiatric comorbidity than those who did not (OR 2.65 95% CI 1.07-6.56). Compared to WWID who had not experienced IPV, victims (70%) were almost two times more likely to meet criteria for post-traumatic stress disorder (OR 1.95 95% CI 1.10-3.48). Psychiatric comorbidity and IPV among WWID are common. Drug treatment and harm reduction services should address psychiatric comorbidity and IPV to improve treatment outcomes.

Influence of side-effects on early therapy persistence with letrozole in post-menopausal patients with early breast cancer: Results of the prospective EvAluate-TM study

BACKGROUND

Endocrine treatment (ET) with an aromatase inhibitor (AI) is the treatment of choice in post-menopausal patients with hormone receptor-positive early breast cancer (EBC). However, adverse events (AEs) often lead to treatment discontinuation. This analysis aimed to identify side-effects that lead to patients failing to persist with letrozole treatment.

PATIENTS AND METHODS

Post-menopausal hormone receptor-positive EBC patients starting ET with letrozole were enroled in EvAluate-TM, a non-interventional study. Information regarding treatment compliance and persistence was gathered in months 6 and 12. Persistence was defined as the time from 30 d after the start to the end of treatment. The influence on persistence of musculoskeletal syndrome, menopausal disorder, sleep disorder and other AEs within the first 30 d was analysed using Cox regression analyses.

RESULTS

Among 3887 patients analysed, the persistence rate after 12 months was >85%. In all, 568 patients (14.6%) discontinued the treatment, 358 of whom (63.0%) did so only because of side-effects. The main AEs influencing persistence were musculoskeletal symptoms (hazard ratio [HR] 2.55; 95% confidence interval [CI], 1.90-3.42), sleep disorders (HR 1.95; 95% CI, 1.41-2.70) and other AEs (HR 2.03; 95% CI, 1.51-2.73). Menopausal disorder was not associated with non-persistence (HR 1.17; 95% CI, 0.74-1.84).

CONCLUSIONS

These results suggest that side-effects of AIs such as musculoskeletal syndrome and sleep disorder lead to ET discontinuation within the first treatment year in significant numbers of EBC patients. Compliance programmes adapted for subgroups that are at risk for early non-persistence might help to ensure the recommended therapy duration.

CLINICAL TRIALS NUMBER

CFEM345DDE19.

Prenatal exposure to methadone or buprenorphine: Early childhood developmental outcomes

BACKGROUND

Methadone and buprenorphine are recommended to treat opioid use disorders during pregnancy. However, the literature on the relationship between longer-term effects of prenatal exposure to these medications and childhood development is both spare and inconsistent.

METHODS

Participants were 96 children and their mothers who participated in MOTHER, a randomized controlled trial of opioid-agonist pharmacotherapy during pregnancy. The present study examined child growth parameters, cognition, language abilities, sensory processing, and temperament from 0 to 36 months of the child's life. Maternal perceptions of parenting stress, home environment, and addiction severity were also examined.

RESULTS

Tests of mean differences between children prenatally exposed to methadone vs. buprenorphine over the three-year period yielded 2/37 significant findings for children. Similarly, tests of mean differences between children treated for NAS relative to those not treated for NAS yielded 1/37 significant finding. Changes over time occurred for 27/37 child outcomes including expected child increases in weight, head and height, and overall gains in cognitive development, language abilities, sensory processing, and temperament. For mothers, significant changes over time in parenting stress (9/17 scales) suggested increasing difficulties with their children, notably seen in increasing parenting stress, but also an increasingly enriched home environment (4/7 scales) CONCLUSIONS: Findings strongly suggest no deleterious effects of buprenorphine relative to methadone or of treatment for NAS severity relative to not-treated for NAS on growth, cognitive development, language abilities, sensory processing, and temperament. Moreover, findings suggest that prenatal opioid agonist exposure is not deleterious to normal physical and mental development.

Saccharomyces boulardii modulates and improves the immune response to Bovine Herpesvirus type 5 Vaccine

ABSTRACT There have been significant efforts towards the development of more efficient vaccines for animal health. A strategy that may be used to improve vaccine efficacy is the use of probiotics to enhance the immune response of the host, leading to increased immunogenicity of antigen preparations. Bovine herpesvirus 5 (BoHV-5) is an example of an important animal pathogen for which vaccines have provided only limited protection. In this study, we examined the use of the probiotic Saccharomyces boulardii (Sb) as a potential adjuvant to improve vaccine efficiency. We found that the supplemented animals exhibited an enhanced systemic IgG antibody response toward a Th1 response in favor of IgG2a and increased mRNA expression levels of the cytokines IFN-y, IL-12, IL-17 and IL-10 in the spleen. These results suggest that Sb supplementation may provide a promising means for improving the efficiency of vaccines, particularly those that rely on a cell-mediated immune response.

Medical Informatics and the Quality of Health: New Approaches to Support Patient Care

Objectives: The Yearbook of Medical Informatics is published annually by the International Medical Informatics Association (IMIA) and contains a selection of excellent papers on medical informatics research which have been recently published (www.yearbook.uni-hd.de). The 2003 Yearbook of Medical Informatics took as its theme the role of medical informatics for the quality of health care. In this paper, we will discuss challenges for health care, and the lessons learned from editing IMIA Yearbook 2003.

Results and Conclusions: Modern information processing methodology and information and communication technology have strongly influenced our societies and health care. As a consequence of this, medical informatics as a discipline has taken a leading role in the further development of health care. This involves developing information systems that enhance opportunities for global access to health services and medical knowledge. Informatics methodology and technology will facilitate high quality of care in aging societies, and will decrease the possibilities of health care errors. It will also enable the dissemination of the latest medical and health information on the web to consumers and health care providers alike. The selected papers of the IMIA Yearbook 2003 present clear examples and future challenges, and they highlight how various sub-disciplines of medical informatics can contribute to this.

Computationally Efficient Noninvasive Cardiac Activation Time Imaging

Objective: The computer model-based computation of the cardiac activation sequence in humans has been recently subject of successful clinical validation. This method is of potential interest for guiding ablation therapy of arrhythmogenic substrates. However, computation times of almost an hour are unattractive in a clinical setting. Thus, the objective is the development of a method which performs the computation in a few minutes run time.

Methods: The computationally most expensive part is the product of the lead field matrix with a matrix containing the source pattern on the cardiac surface. The particular biophysical properties of both matrices are used for speeding up this operation by more than an order of magnitude. A conjugate gradient optimizer was developed using C++ for computing the activation map.

Results: The software was tested on synthetic and clinical data. The increase in speed with respect to the previously used Fortran 77 implementation was a factor of 30 at a comparable quality of the results. As an additional finding the coupled regularization strategy, originally introduced for saving computation time, also reduced the sensitivity of the method to the choice of the regularization parameter.

Conclusions: As it was shown for data from a WPW-patient the developed software can deliver diagnostically valuable information at a much shorter span of time than current clinical routine methods. Its main application could be the localization of focal arrhythmogenic substrates.

A Signal Processing Pipeline for Noninvasive Imaging of Ventricular Preexcitation

Objectives: Noninvasive imaging of the cardiac activation sequence in humans could guide interventional curative treatment of cardiac arrhythmias by catheter ablation. Highly automated signal processing tools are desirable for clinical acceptance. The developed signal processing pipeline reduces user interactions to a minimum, which eases the operation by the staff in the catheter laboratory and increases the reproducibility of the results.

Methods: A previously described R-peak detector was modified for automatic detection of all possible targets (beats) using the information of all leads in the ECG map. A direct method was applied for signal classification. The algorithm was tuned for distinguishing beats with an adenosine induced AV-nodal block from baseline morphology in Wolff-Parkinson-White (WPW) patients. Furthermore, an automatic identification of the QRS-interval borders was implemented.

Results: The software was tested with data from eight patients having overt ventricular preexcitation. The R-peak detector captured all QRS-complexes with no false positive detection. The automatic classification was verified by demonstrating adenosine-induced prolongation of ventricular activation with statistical significance (p <0.001) in all patients. This also demonstrates the performance of the automatic detection of QRS-interval borders. Furthermore, all ectopic or paced beats were automatically separated from sinus rhythm. Computed activation maps are shown for one patient localizing the accessory pathway with an accuracy of 1 cm.

Conclusions: The implemented signal processing pipeline is a powerful tool for selecting target beats for noninvasive activation imaging in WPW patients. It robustly identifies and classifies beats. The small beat to beat variations in the automatic QRS-interval detection indicate accurate identification of the time window of interest.

Atrial and Ventricular Myocardium Extraction Using Model-based Techniques

Objectives: This paper presents an efficient approach for extracting myocardial structures from given atrial and ventricular blood masses to enable non-invasive estimation of electrical excitation in human atria and ventricles.

Methods: Based on given segmented atrial and ventricular blood masses, the approach constructs the myocardial structure directly, in the case that the myocardium can be detected in the volume data, or by using mean model information, in the case that the myocardium cannot be seen in the volume data due to image modalities or artefacts. The approach employs mathematical and gray-value morphology operations. Regulated by the spatial visibility of the myocardial structure in the medical image data especially the atrial myocardium needs to be estimated repeatedly using the a-priori knowledge given by the anatomy.

Results: The approach was tested using eight patient data sets. The reconstruction process yielded satisfying results with respect to an efficient generation of a volume conductor model which is essential when trying to implement the estimation of electrical excitation in clinical application.

Conclusion: The approach yields ventricular and atrial models that qualify for cardiac source imaging in a clinical setting.

Towards Clinical Bioinformatics: Advancing Genomic Medicine with Informatics Methods and Tools

Objectives: To summarize the challenges facing clinical applications in the light of growing research results in genomic medicine and bioinformatics.

Methods: Analysis of the contents of the Yearbook of Medical Informatics 2004 of the International Medical Informatics Association (IMIA).

Results: The Yearbook of Medical Informatics 2004 includes 32 articles selected from 22 peer-reviewed scientific journals. A special section on clinical bio-informatics highlights recent developments in this field. Several guest editors review the promises and limitations of available methods and resources from biomedical informatics that are relevant to clinical medicine. Integrated data and knowledge resources are generally regarded to be central and key issues for clinical bioinformatics. Further review papers deal with public health implications of bioinformatics, knowledge management and trends in health care education. The Yearbook includes for the first time a section on the history of medical informatics, where the significant impact of the Reisensburg protocol 1973 on international health and medical informatics education is examined.

Conclusions: Close collaboration between bio-informatics and medical informatics researchers can contribute to new insights in genomic medicine and contribute towards the more efficient and effective use of genomic data to advance clinical care.

AAM-based Segmentation for Imaging Cardiac Electrophysiology

Objectives: Activation time (AT) imaging from electrocardiographic (ECG) mapping data has been developing for several years. By coupling 4-dimensional volume data (3D + time) the electrical sequence can be computed non-invasively. In this paper an approach for extracting the ventricular and atrial blood masses for structurally normal hearts by using cine-gated shortaxis data obtained via magnetic resonance imaging (MRI) is introduced.

Methods: The blood masses are extracted by employing Active Appearance Models (AAMs). The ventricular blood masses are segmented, applying the AAMs after providing apex cordis and base of the heart in the volume data, whereas the more complex geometry of the atria requires a more specific attempt. On account of this the atrium was divided into three divisions of appearance, where the images of the volume data in the related divisions have a maximum affinity. The first division reaches from the base of the heart to initial visibility of the upper and left lower pulmonary vein. The second division up from there to the last occurrence and the third division from there to the end of the visibility of the right upper and lower pulmonary vein. After extracting the cardiac blood masses the result gets triangulated and remeshed for activation time imaging.

Results: With this method the cardiac models of eight patients were extracted and the AT imaging approach was applied to single-beat ECG data of atrial and ventricular depolarization.

Conclusion: The advantage of the proposed AAM approach is that only a few initial parameters have to be set. Therefore, the approach can be integrated into a processing pipeline that works semi-automatically. The extracted models can be used for further investigations.

Prediction of Countershock Success

Objectives: Spectral analysis of the ventricular fibrillation (VF) ECG has been used for predicting countershock success, where the Fast Fourier Transformation (FFT) is the standard spectral estimator. Autoregressive (AR) spectral estimation should compute the spectrum with less computation time. This study compares the predictive power and computational performance of features obtained by the FFT and AR methods.

Methods: In an animal model of VF cardiac arrest, 41 shocks were delivered in 25 swine. For feature parameter analysis, 2.5 s signal intervals directly before the shock and directly before the hands-off interval were used, respectively. Invasive recordings of the arterial pressure were used for assessing the outcome of each shock. For a proof of concept, a micro-controller program was implemented.

Results: Calculating the area under the receiver operating characteristic (ROC) curve (AUC), the results of the AR-based features called spectral pole power (SPP) and spectral pole power with dominant frequency (DF) weighing (SPPDF) yield better outcome prediction results (85 %; 89 %) than common parameters based on FFT calculation method (centroid frequency (CF), amplitude spectrum area (AMSA)) (72%; 78%) during hands-off interval. Moreover, the predictive power of the feature parameters during ongoing CPR was not invalidated by closed-chest compressions. The calculation time of the AR-based parameters was nearly 2.5 times faster than the FFT-based features.

Conclusion: Summing up, AR spectral estimators are an attractive option compared to FFT due to the reduced computational speed and the better outcome prediction. This might be of benefit when implementing AR prediction features on the microprocessor of a semi-automatic defibrillator.