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.

Ventricular surface activation time imaging from electrocardiogram mapping data

Non-invasive imaging of cardiac electrophysiology provides a non-invasive way of obtaining information about electrical excitation. An iterative algorithm based on a general regularisation scheme for non-linear, ill-posed problems in Hilbert scales was applied to the electrocardiographic inverse problem, imaging the ventricular surface activation time (AT) map. This method was applied to electrocardiographic data from a 31-year-old healthy volunteer and a 24-year-old patient suffering from a Wolff-Parkinson-White (WPW) syndrome. The objective was to evaluate non-invasive AT imaging of an autonomous sinus rhythm and to quantify the localisation error of non-invasive AT imaging by localising the accessory pathway of the WPW syndrome and a pacing site for left ventricle pacing. The distances between the invasive and non-invasive localisation of the pacing site and the accessory pathway were 8 mm and 5 mm. The clinical case presented, shows that this non-invasive AT imaging approach may enable the reconstruction of single focal events with sufficient accuracy for potential clinical application.

Safety and Efficacy of Vardenafil for the Treatment of Men With Erectile Dysfunction After Radical Retropubic Prostatectomy

PURPOSE

More than one-third of men may experience erectile dysfunction (ED) after nerve sparing radical retropubic prostatectomy. The efficacy and safety of vardenafil, a potent, selective, phosphodiesterase 5 inhibitor, was assessed for the treatment of ED after radical prostatectomy.

MATERIALS AND METHODS

In this double-blind study 440 men with ED after nerve sparing radical prostatectomy were randomized to take placebo, or 10 or 20 mg vardenafil. Efficacy was measured after 12 weeks using the erectile function domain of the International Index of Erectile Function, diary questions measuring vaginal penetration and intercourse success rates, and a global assessment question (GAQ) on erection.

RESULTS

Of the intent to treat population 70% had severe ED (erectile function less than 11) at baseline. After 12 weeks both vardenafil doses were significantly superior to placebo (p <0.0001) for all efficacy variables. Improved erections (based on GAQ) were reported by 65.2% and 59.4% of patients on 20 and 10 mg vardenafil, respectively, and by only 12.5% of patients on placebo (p <0.0001). Among men with bilateral neurovascular bundle sparing, positive GAQ responses were reported by 71.1% and 59.7% of patients on 20 and 10 mg vardenafil, respectively, versus 11.5% of those on placebo (p <0.0001). The average intercourse success rate per patient receiving 20 mg vardenafil was 74% in men with mild to moderate ED and 28% in men with severe ED, compared to 49% and 4% for placebo, respectively. Few adverse events were observed. They were generally mild to moderate headache, flushing and rhinitis.

CONCLUSIONS

In men with severe ED after nerve sparing radical retropubic prostatectomy, vardenafil significantly improved key indices of erectile function.

Clinical pathways--can they be used in trauma care. An analysis of their ability to fit the patient

This study prospectively evaluated the appropriateness and ability of clinical pathways to fit trauma patients in five key conditions, severe head injury, fractured ribs, fractured pelvis, fractured femur and blunt abdominal trauma, who were admitted to a single Level 1 Trauma Centre, between February and July 1999. Each pathway consisted of 14 elements of care divided into observable outcomes. Failure to achieve an outcome resulted in a variance or deviation from the pathway, which was assessed by the number of non-applicable variances. Appropriateness of clinical pathways was assessed by the applicability index (the number of non-applicable variances divided by the potential variances). Critical mismatches occurred when non-applicable variances exceeded 50% of potential variances. 146 patients, with the mean age 41.9 years (S.D. 20.7), mean ISS 11.1 (S.D. 10.7) were enrolled; 18 with severe head injury, 59 with fractured ribs, 13 with fractured pelvis, 20 with fractured femur and 36 with blunt abdominal trauma. Critical mismatch occurred in seven patients. Applicability indexes were 87 for head, 93 for ribs, 92 for blunt abdominal trauma, 91 for femur and 92 for the pelvic pathway. Patient assessment, pain management, skin integrity and patient education were the most appropriate key elements of care, discharge planning, patient satisfaction, treatment and activity were least applicable. This study identified, for the first time, that clinical pathways are clinically appropriate for major trauma conditions.

Intramuscular injection of insulin lispro or soluble human insulin: pharmacokinetics and glucodynamics in Type 2 diabetes

AIM

The aim of the study was to compare the pharmacokinetics and glucodynamics of insulin lispro and soluble human insulin following intramuscular (i.m.) injection in patients with Type 2 diabetes with secondary failure of sulphonylureas.

METHODS

Single 15-U i.m. doses of insulin lispro or soluble human insulin were administered to 16 patients in a two-way, randomized, crossover design. Glucodynamic and pharmacokinetic parameters were determined over 6 h after insulin injection using clamp techniques.

RESULTS

Insulin C(max) was significantly higher (971 +/- 217 vs. 659 +/- 141 pmol/l, P < 0.001) and T(max) was significantly shorter (46.9 +/- 27 vs. 94.7 +/- 50.1 min, P = 0.002) with insulin lispro. Glucose infusion rate (GIR) curves showed clear separation 20 min after injection and were significantly greater for insulin lispro during the 40-60, 60-80 and 80-100-minute time intervals. Total glucose infused was only approximately 5% larger with insulin lispro during the 6-h follow-up, due to lower insulinaemia at later time points. The glucose R(max) and TR(max) were not statistically different between insulin treatments.

CONCLUSION

This study shows that i.m. injection of insulin lispro is followed by its more rapid absorption, which results in stronger metabolic effect in the first 2 h when compared with soluble human insulin under the same test conditions. Diabet. Med. 18, 562-566 (2001)

Trauma case management and clinical pathways: prospective evaluation of their effect on selected patient outcomes in five key trauma conditions

BACKGROUND

This study evaluated the implementation of clinical pathways and case management between July 1998 and July 1999 in five key trauma conditions: severe head injury, fractured ribs, fractured pelvis, blunt abdominal trauma, and fractured femurs presenting to a single trauma service.

METHODS

Thirteen key elements of care with expected outcomes were defined for each key trauma condition. Deviations from expected outcome were defined as variances. Attainment of the expected outcomes was measured before (stage 1) and after introduction (stages 2 and 3) of clinical pathways and case management. Nonattained outcomes were quantified and categorized into time of occurrence, and relationship to staff, patient, or system.

RESULTS

Two hundred thirty-five patients were studied, with a mean age of 41.8 (SD, 20.6) years and mean Injury Severity Score (ISS) of 11.7 (SD, 11.0). The mean number of observed variances per patient for stage 1 was 51.7 (SD, 43.5); stage 2, 42.3 (SD, 32.9); and stage 3, 23.2 (SD, 21.7) (p = 0.0001 for both stage 1 and stage 2 compared with stage 3). There was a significant improvement in outcomes achieved from stage 1 (92.7%; 95% confidence interval, 92.5-92.9%), to stage 3 (96.7%; 95% confidence interval, 96.5-96.9%). Of the total number of variances seen, 0.2% related to system errors, 25% related to patient factors, and 75.8% related to staff. The proportion of staff-related variances was significantly reduced in stage 3.

CONCLUSION

Clinical pathways and case management identified areas in need of remedial action and improved the delivery of patient care to our trauma population. It has set a template for the future management of our trauma service.

An evaluation of trauma team response in a major trauma hospital in 100 patients with predominantly minor injuries

BACKGROUND

A prospective study of trauma team response and performance at a major trauma service was undertaken between June and September 1998.

METHODS

Following activation of the trauma team, the timing of the trauma team's arrival, the subsequent early management of the patient, time to monitoring, X-ray investigation and procedures performed were documented.

RESULTS

The study evaluated 100 activations, 76% male, mean age 32 years and 65% were due to road trauma. The team leader, airway doctor and surgical registrar were present on patient arrival in 96%, 90% and 76% of cases, respectively. The airway, procedure and scribe nurses were present on patient arrival in 77%, 97% and 95% of cases, respectively. The radiographer was present in 69% of cases. Comparison between normal and after-hour response revealed little difference in medical and radiographer response, but the after-hour nurse response was significantly worse (P < 0.001). The median time to achieve electrocardiogram monitoring, blood pressure reading, and oxygen saturation tracing was 3 (range: 1-13), 4 (range: 2-20) and 3 (range: 1-21) min, respectively. Intravenous cannulation, phlebotomy and dispatch of bloods occurred at median times of 5 (range: 2-22), 6 (range: 3-23) and 17 (range: 7-40) min. The median times for intubation, chest tube and splintage of fracture were 10 (range: 3-19), 10 (range: 6-14) and 26 (range: 19-55) min, respectively.

CONCLUSIONS

The present study identified an excellent multidisciplinary trauma response and provides a template to improve performance in early trauma management.

Trauma outcomes: a death analysis study

Survival and mortality outcomes for trauma patients admitted to Liverpool Hospital, Sydney were analysed to determine the adequacy of trauma care. TRISS and ASCOT survival probabilities and peer review were utilised to determine if deaths were avoidable. Evaluation methods were compared for assessment of care. During the study period 2205 trauma patients were admitted, 518 of which fulfilled the study entry criteria. There were 38 deaths. The age and Injury Severity Score (ISS) of survivors was 34 +/- 18 years, 9.8 +/- 9 (mean +/- sd) compared to age and ISS for nonsurvivors 37 +/- 22 years and 45 +/- 22*, *p < 0.001. Peer review suggested that 32 deaths were non avoidable, 4 potentially avoidable and 2 were probably avoidable. TRISS and ASCOT survival probabilities were > 0.5 in 16 and 18 patients respectively. TRISS and ASCOT had low positive predictive value (25%) in identifying avoidable deaths. The Z Score was 1.79. The standardised mortality ratio (SMR) was 1.16. The Effectiveness (E) value for outcome was 0.91. Poor communication within the Area Trauma System was the greatest contributor to avoidable deaths. All trauma deaths need peer review rather than solely relying upon ASCOT and TRISS probabilities to identify "unexpected" deaths for detailed review.

Evaluation of the prevalence of drug and alcohol abuse in motor vehicle trauma in south western Sydney

This study estimated prospectively the prevalence of high drug and alcohol levels in road trauma cases who met the criteria for activation of the Liverpool Hospital's trauma team. Urine analysis of road trauma victims between October 1992 and October 1993 was undertaken for drug and alcohol estimation. A total of 164 drivers were studied. A urine alcohol concentration (UAC) exceeding 0.08 g/dL was detected in 27 drivers (16.5%). Cannabinoids were detected in the urine of 25 drivers (15.2%), in 17 the concentrations exceeded 400 ng/mL. In one instance amphetamine, cocaine and heroin were detected in the same injured driver. Combined use of alcohol with some other drugs was detected in only four drivers. Alcohol and cannabinoid levels were prevalent in the urine of injured drivers in this study, particularly in young males who remain over-represented in the group of injured drivers. In the population surveyed other drugs were rarely detected. The role of cannabinoids in road trauma and the use of cannabinoids in young male drivers will however need to be monitored more extensively.

A modified combination technique for performing diagnostic peritoneal lavage

Existing open diagnostic peritoneal lavage techniques (DPL) use small bore catheters, through a small lower midline incision or infra-umbilical incision. This study evaluated a modified DPL technique using a 10 mm umbilical incision, with open insertion of a 20 French peritoneal lavage catheter. The catheter has 27 radial side holes in the terminal distal 13 cm, and a female Leur lock connector. Warmed saline is infused via a cystoscopy infusion set. The time required to perform a new technique was studied in 10 patients. The median time to catheter insertion was 2.4 +/- 3.8 min, infusion time 0.75 +/- 0.3 min, effusion time 0.3 +/- 1.7 min, and a median total time of 7.6 +/- 4.2 min (median +/- s.d.). There was no complications. This technique of DPL is cosmetically attractive, much quicker than existing techniques and we have found its initial use encouraging.

A prospective study of the performance of the trauma team leader

This study assessed the performance of the trauma team leader in 50 consecutive trauma resuscitations at Liverpool Hospital over a two-month period. The trauma team consists of intensive care (ICU), emergency, and surgical registrars, three nurses, a wardsman, a radiographer, and a social worker. The team leader position alternates between the ICU and emergency registrar on a fortnightly roster. A panel of specialists experienced in trauma management evaluated 38 aspects of the initial resuscitation. Individual variables received different weightings. The maximum possible score for team leader performance was 80. The mean team leader score was 70.4 +/- 8 (SD). The main deficiencies in the team leader's performances were in their interpersonal communications and in the adequacy of documentation of the history of the injury. In 20% of resuscitations there were failures to completely expose the patient. Medical skills were uniformly well performed. Poor communication with other team members were the main pitfall of the team leader in this study. The team leader score may prove a useful tool in improving the quality of the trauma team.

IL-1, TNF-alpha and IL-2 production by peritoneal and spleen cells from Schistosoma mansoni infected mice and its potentiation by preimmunization with schistosomal antigens and immunostimulants

In the present study we tested the effect of immunization with schistosome derived antigens such as frozen-thawed schistosomula in combination with either BCG, liposomes or liposomal muramyl tripeptide-phosphatidyl ethanolamine (MTP-PE), on the resistance of mice to infection, and on the function of their macrophages and lymphocytes. Immunization with either F-T schistosomula + BCG or F-T schistosomula + MTP-PE and subsequent infection, resulted in a 2-3-fold increase in adherent peritoneal macrophage-mediated schistosomulicidal activity (SCA). Peritoneal and spleen macrophages from immunostimulant treated and/or immunized animals showed a significant increase in LPS triggered TNF-alpha production, as compared to non-treated controls. The highest increase in TNF-alpha production was achieved after immunization with either F-T schistosomula + BCG or F-T schistosomula + MTP-PE. LPS triggered IL-1 production was elevated in spleen and peritoneal macrophages from F-T schistosomula + BCG treated mice, and also in spleen macrophages treated with F-T schistosomula + MTP-PE. Only immunization with F-T schistosomula + BCG increased ConA-induced spleen lymphocyte proliferation and IL-2 production. Immunization of mice with F-T schistosomula + BCG also induced protection against parasite infection, while F-T schistosomula + MTP-PE failed to do so. Potentiation of antischistosomal resistance seems to require both macrophage and lymphocyte activation which was achieved only when BCG served as an immunostimulant.

The schistosomulicidal activity and the production of IL-1 and TNF-alpha by peritoneal macrophages from infected mice and their potentiation by muramyl tripeptide-phosphatidyl ethanolamine (MTP-PE) treatment

Production of TNF-alpha and IL-1 by adherent peritoneal exudate macrophages (APEM) was monitored for 20 weeks in Schistosoma mansoni infected mice in comparison to their schistosomulicidal activity. LPS-triggered IL-1 and TNF-alpha production by APEM peaked 10 weeks post infection (p.i.) and declined thereafter. The schistosomulicidal activity of APEM also peaked after 10 weeks but remained elevated thereafter. Infected mice were also treated with the immunostimulator liposomal muramyl tripeptide-phosphatidyl ethanolamine (MTP-PE) 6 or 10 weeks p.i., and their APEM were tested 4 weeks later. APEM from such treated animals showed elevated IL-1 and TNF-alpha production when treatment commenced 6 weeks p.i., while their schistosomulicidal activity increased when treatment commenced either 6 or 10 weeks p.i. The L-arginine inhibitor, NG monomethyl arginine, markedly inhibited the schistosomulicidal activity but not the IL-1 and TNF-alpha production of APEM. Our results show that monokine production increases during the acute phase of infection and declines during its chronic phase, while macrophage schistosomulicidal activity remains constant throughout. Furthermore, TNF-alpha or IL-1 may play a minor role in APEM mediated killing of schistosomula.

On the interaction between macrophages and developmental stages of Schistosoma mansoni: effect of muramyl tripeptide phosphatidyl ethanolamine (MTP-PE) treatment on mice survival and the generation of schistosomulicidal macrophages

Schistosomiasis is a chronic disease afflicting hundreds of millions of people throughout the world against which there is as yet no effective vaccine. In the present study we tested the effect of the immunomodulator muramyl tripeptide phosphatidyl ethanolamine (MTP-PE) on the survival of Schistosoma mansoni-infected mice and on the induction in them of schistosomulicidal macrophages. Mice exposed to 80 cercariae each and then treated with MTP-PE showed prolonged survival following either single or repeat infection. The treatment with MTP-PE, when initiated 70 days post the schistosome infection, diminished significantly the mortality of infected mice over an observed period of 110 days. In terms of treatment efficacy there was no evident difference between the intravenous and intraperitoneal mode of administration of the drug. MTP-PE treatment significantly reduced granuloma size and markedly diminished liver damaged as judged by the lower levels of alkaline phosphatase in the serum. Such treatment exerted no significant effect on the spleen or liver weight in infected mice nor on the worm burden resulting from either a single or double infection. In infected and non-treated mice, schistosomulicidal macrophages appeared after 8-10 weeks of infection. In infected mice treated with MTP-PE there was an accelerated appearance of such macrophages and these exhibited a greater cidal effect on the schistosomula. These immunostimulatory and life-prolonging effects of MTP-PE on S. mansoni-infected mice might indicate an effect of this reagent on cells involved in the granulomatous process.

Age-related development of a heterozygous phenotype in solitary neurons of the homozygous Brattleboro rat

A single-base deletion in the single-copy vasopressin gene is the cause of diabetes insipidus in the homozygous Brattleboro rat (di/di). It results in the synthesis of an altered vasopressin precursor of which the axonal transport is blocked. Paradoxically, a small number of solitary hypothalamic neurons displays all the immunoreactivities of the wild-type vasopressin precursor (i.e., vasopressin, neurophysin, and a glycopeptide). In the present paper we provide evidence that these neurons have undergone a switch to a genuine heterozygous (di/+) phenotype; i.e., they contain the immunoreactivities of both the wild-type and the mutated vasopressin precursors. In the neural lobe, glycopeptide fibers are also present, showing that axonal transport of the wild-type precursor is restored. Moreover, the number of neurons displaying this di/+ phenotype increases markedly and in a linear way (from 0.1% up to 3% of the vasopressin cells) with age. These findings indicate that after mitotic division has ceased, genomic alterations occur in somatic neurons in vivo. The molecular event generating the di/+ phenotype in the di/di animal could involve a somatic intrachromosomal gene conversion between the homologous exons of the vasopressin and the related oxytocin genes.

Modulation of carcinoembryonic antigen release by HT-29 colon carcinoma line in the presence of different agents

In this study we followed the effects of various differentiating agents on the expression of carcinoembryonic antigen (CEA) released into the medium by a colon carcinoma cell line HT-29. Butyric acid 1 mM markedly increased the level of CEA (12-fold in comparison to control levels). 12-O-tetradecanoyl-phorbol-13-acetate (TPA) 50 ng/ml and 5-azacytidine 4 x 10(-6) M increased the amount of CEA, 2- and 1.5-fold respectively. On the other hand retinoic acid 10(-5) M, N methyl-formamide 1% and N,N hexamethylene bisacetamide 2.5 mM decreased CEA 2-, 4- and 3-fold respectively. Our results emphasize that various differentiating agents affect CEA levels differently. Thus changes in CEA levels appear not to be reliable as a marker of a more differentiated phenotype.

Macrophage microtubules: an optimized method for the assay of tubulin concentration and state of polymerization in macrophages

We describe a method for the assay of total tubulin content and the tubulin dimer/polymer ratio in cultured macrophages (MPs). The assay is based on the specific binding of [3H]colchicine to tubulin dimer units and on the separation of free and tubulin-complexed [3H]colchicine on diethylaminoethyl (DEAE)-cellulose filters. The native state of microtubules (MTs) was conserved by suspending the cells in a microtubule-stabilizing solution specifically adapted for use with MPs and by disrupting the cells under carefully chosen conditions. Intact MTs were isolated from the cell homogenate by centrifugation at 150,000 X g and were subsequently depolymerized. [3H]Colchicine binding assays were performed on both the supernatant fraction, containing the pool of soluble tubulin, and on the deploymerized MTs. By using this method, we examined the influence of low temperature and of a number of agents known to affect MP function, on the tubulin dimer/polymer ratio in guinea pig peritoneal MPs. The results of the biochemical assay correlated well with the published information, derived by morphologic and functional approaches, on the effect of cold and of these agents on MTs in phagocytic cells.

Intrahepatic portal vein sclerosis in patients without a history of liver disease. An autopsy study

Portal fibrosis with portal venous obliteration is characteristic of noncirrhotic portal hypertension, but similar lesions are also commonly seen in patients without clinical evidence of liver disease. Thus, the ability to predict the presence of portal hypertension with histologic criteria will probably depend on a quantitative assessment of liver tissue. The purpose of this study is to provide a quantitative basis in a "normal" population for evaluation of portal vein obliteration. We reviewed 414 consecutive autopsies of patients without known history of alcoholism or clinical liver disease. Intrahepatic portal vein obliteration was graded 0 to III. The grading system was standardized by morphometry on 34 selected cases. The incidence of portal vein lesions increased with age and reached a plateau at about 60 years of age. Lesions were more common in patients who had severe congestive heart failure or arterial thrombosis. These associations suggest that obliterative lesions may be the result of thrombosis in patients with sluggish portal blood flow or hypercoagulability. Portal tract mineral oil deposits may also have a role, because they were found more often than expected in livers with portal sclerosis.