Miniaturized Multi Sensor Implant for Monitoring of Hemodynamic Parameters.

t a novel miniaturized multi sensor implant for monitoring hemodynamic parameters in cardiovascular regions. Pressure measurements are performed with a highly accurate capacitive pressure sensor. An additional acceleration and temperature sensor allows compensating the impact of patient's inclination and temperature variations on the pressure measurement, respectively. A multi-functional transponder application-specific integrated circuit (ASIC) manages sensor signal processing, storage of ID, sensor calibration data, telemetric energy, and data transmission with an extracorporeal reading unit. Each component of the implant is assembled on a low temperature co-fired ceramics (LTCC) circuit board with an integrated antenna coil enabling an inductive near-field coupling at a frequency of 13.56 MHz. For a streamlined shape and reduction of thrombogenicity, the implant is encapsulated by biocompatible polymers.

Biosensor microprobes with integrated microfluidic channels for bi-directional neurochemical interaction.

This paper reports on silicon-based microprobes, 8 mm long and 250 µm × 250 µm cross-section, comprising four recessed biosensor microelectrodes (50 µm × 150 µm) per probe shank coated with an enzymatic layer for the selective detection of choline at multiple sites in brain tissue. Integrated in the same probe shank are up to two microfluidic channels for controlled local liquid delivery at a defined distance from the biosensor microelectrodes. State-of-the-art silicon micromachining processing was applied for reproducible fabrication of these experiment-tailored multi-functional probe arrays. Reliable electric and fluidic interconnections to the microprobes are guaranteed by a custom-made holder. The reversible packaging method implemented in this holder significantly reduces cost and assembly time and simplifies storage of the biosensor probes between consecutive experiments. The functionalization of the electrodes is carried out using electrochemically aided adsorption. This spatially controlled deposition technique enables a parallel deposition of membranes and is especially useful when working with microelectrode arrays. The achieved biosensors show adequate characteristics to detect choline in physiologically relevant concentrations at sufficient temporal and spatial resolution for brain research. Sensitivity to choline better than 10 pA µm(-1), detection limit below 1 µM and response time of 2 s were obtained. The proposed combination of biosensors and microfluidic injectors on the same microprobe allows simultaneous chemical stimulation and recording as demonstrated in an agarose gel-based brain phantom.

[What is new in the 2009 ESC guidelines?]. / Was ist neu in der ESC-Leitlinie von 2009?

The 2009 ESC guideline emphasizes active risk stratification and the diagnostic strategy of prolonged ECG monitoring using an implantable loop recorder. The initial evaluation aims at establishing a prima vista diagnosis or at least a diagnostic hypothesis and risk stratification according to ECG criteria and clinical findings. Carotid sinus massage as a diagnostic procedure remains controversial. Electrophysiological study for evaluation of suspected arrhythmogenic syncope is of decreasing relevance. The loop recorder enables documentation of the rhythm during a subsequent syncope. Neurological work-up is not routinely recommended. A standardized evaluation minimizes the rate of unexplained syncopes. Therapeutic decisions include ICD or pacemaker, as indicated in cases of arrhythmogenic syncope or carotid sinus syncope, and mostly general measures in case of other reflex syncopes.

[Reflex syncope : diagnosis and therapy]. / Reflexsynkope : Diagnostik und Therapie.

Reflex-mediated syncope is a common cause for syncope. The first step in evaluating the cause of syncope is to assess the risk of a life-threatening cause for syncope, e.g., ventricular arrhythmias. Reflex-mediated syncope has to be differentiated from orthostatic syncope. In orthostatic syncope, there is an insufficient autonomic response. In contrast to a reflex-mediated syncope, in which the autonomic nervous system acts inappropriately, reflex-mediated syncope is classified into the classical vasovagal form, the situational form, or due to carotid sinus hypersensitivity. In the elderly, often a mixed form is present. Treatment is difficult. Most important is educating the patient and avoiding precipitating factors. Physical maneuvers, e.g., counter pressure maneuvers, are more effective than drug treatment. Permanent pacing is rarely needed. However, before indicating a pacemaker, a correlation between bradycardia and syncope should be documented. This is often only possible by implanting a monitoring device at an early stage.

Two-dimensional multi-channel neural probes with electronic depth control.

This paper presents multi-electrode arrays for in vivo neural recording applications incorporating the principle of electronic depth control (EDC), i.e., the electronic selection of recording sites along slender probe shafts independently for multiple channels. Two-dimensional (2D) arrays were realized using a commercial 0.5- µm complementary-metal-oxide-semiconductor (CMOS) process for the EDC circuits combined with post-CMOS micromachining to pattern the comb-like probes and the corresponding electrode metallization. A dedicated CMOS integrated front-end circuit was developed for pre-amplification and multiplexing of the neural signals recorded using these probes.

[ICD therapy as secondary prevention]. / ICD-Therapie zur Sekundärprävention.

Patients who survive out-of-hospital cardiac arrest or symptomatic ventricular tachyarrhythmias are at considerable risk of recurrence of these events and ultimately death. The implantation of an implantable cardioverter defibrillator (ICD) in patients with previous sustained ventricular tachyarrhythmias (VT) is considered secondary prevention of sudden cardiac death. The purpose of this review is to summarize the most important trials on secondary prevention with an ICD. The results from a meta-analysis showed a relative-risk reduction of 28% in overall mortality. Compared with amiodarone, an ICD provided maximal benefit for those patients with an ejection fraction between 20% and 35%. The results of the ICD trial demonstrate that there is clear evidence for the effectiveness of an ICD in patients with unstable VT; however, for patients with stable VT the results are less clear. Data on older patients are scant, and whether the survival benefit observed in the middle aged and younger-old also extend to older elderly patients with a more limited life span is less clear. Therefore, as the population becomes older, it is important to evaluate the safety, effectiveness, and the cost effectiveness of ICD implantation in this population. Guidelines are important and helpful to guide clinical decisions, but the indication for an ICD still remains an individual decision after evaluation of the risks and benefits for the individual patient. However, the patient needs to be involved, which emphasizes the importance of dialogue between the patient and physician.

Systems ambiguity and guideline compliance: a qualitative study of how intensive care units follow evidence-based guidelines to reduce healthcare-associated infections.

BACKGROUND: Consistent compliance with evidence-based guidelines is challenging yet critical to patient safety. We conducted a qualitative study to explore the underlying causes for non-compliance with evidence-based guidelines aimed at preventing four types of healthcare-associated infections in the surgical intensive care unit (SICU) setting. METHODS: Twenty semistructured interviews were conducted with attending physicians (3), residents (2), nurses (6), quality improvement coordinators (3), infection control practitioners (2), respiratory therapists (2) and pharmacists (2) in two SICUs. Using a grounded theory approach, we performed thematic analyses of the interviews. RESULTS: The concept of systems ambiguity to explain non-compliance with evidence-based guidelines emerged from the data. Ambiguities hindering consistent compliance were related to tasks, responsibilities, methods, expectations and exceptions. Strategies reported to reduce ambiguity included clarification of expectations from care providers with respect to guideline compliance through education, use of visual cues to indicate the status of patients with respect to a particular guideline, development of tools that provide an overview of information critical for guideline compliance, use of standardised orders, clarification of roles of care providers and use of decision-support tools. CONCLUSIONS: The concept of systems ambiguity is useful to understand causes of non-compliance with evidence-based guidelines aimed at reducing healthcare-associated infections. Multi-faceted interventions are needed to reduce different ambiguity types, hence to improve guideline compliance.

Microprobe array with low impedance electrodes and highly flexible polyimide cables for acute neural recording.

This paper reports on a novel type of silicon-based microprobes with linear, two and three dimensional (3D) distribution of their recording sites. The microprobes comprise either single shafts, combs with multiple shafts or 3D arrays combining two combs with 9, 36 or 72 recording sites, respectively. The electrical interconnection of the probes is achieved through highly flexible polyimide ribbon cables attached using the MicroFlex Technology which allows a connection part of small lateral dimensions. For an improved handling, probes can be secured by a protecting canula. Low-impedance electrodes are achieved by the deposition of platinum black. First in vivo experiments proved the capability to record single action potentials in the motor cortex from electrodes close to the tip as well as body electrodes along the shaft.

The prognostic impact of successful cardioversion of atrial fibrillation in patients with organic heart disease.

The aim of the study was to evaluate the prognostic impact of successful cardioversion (CV) compared to failed CV in patients with atrial fibrillation (AF) and organic heart disease. A total of 471 consecutive patients with organic heart disease from the prospective single center anticoagulation registry ANTIK who underwent CV of AF or atrial flutter were analyzed. 417 patients (89%) could be successfully cardioverted. In 54 patients (11%) CV failed, these patients remained in AF. After 5 years there were 92 (24%) deaths among patients with restored sinus rhythm at index admission and 20 (38%) deaths among those who remained in AF after CV (unadjusted OR 1.9, 95% CI 1.1-3.6). After adjustment for age, gender and ejection fraction, successful CV was not associated with a beneficial effect on mortality (OR 0.72, 95% CI 0.43-1.21). Thus, successful CV is not an independent predictor of mortality on multivariate analysis. However, it remains a marker for a better prognosis in patients with organic heart disease as these patients have a lower unadjusted longterm mortality.

In-hospital time to treatment of patients with acute ST elevation myocardial infarction treated with primary angioplasty: determinants and outcome. Results from the registry of percutaneous coronary interventions in acute myocardial infarction of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausarzte.

OBJECTIVE: To determine the predictors of time between presentation and primary angioplasty and the influence of this delay time on in-hospital mortality in clinical practice. DESIGN: Analysis of data from the registry of percutaneous coronary interventions in acute myocardial infarction of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK). PATIENTS: Data of 4815 patients registered at 80 hospitals between 1994 and 2000 were analysed. RESULTS: Mean age of the patients was 61.4 (12.5) years. Cardiogenic shock was present in 14.1%. Mean time from admission to primary angioplasty ("door to angiography" time) was 83 (122) minutes. Logistic regression analysis showed the presence of a bundle branch block (odds ratio (OR) 1.95, 95% confidence interval (CI) 1.15 to 3.29), prior coronary artery bypass grafting (OR 1.67, 95% CI 1.08 to 2.59), pre-hospital delay > 3 hours (OR 1.61, 95% CI 1.37 to 1.89), and female sex (OR 1.21, 95% CI 1.01 to 1.45) to be independently associated with longer door to angiography times, whereas a higher hospital volume of performing primary angioplasty (OR 0.53, 95% CI 0.46 to 0.62) and the year of the investigation (OR 0.96, 95% CI 0.92 to 1.00) were independently associated with shorter door to angiography times. Independent predictors of in-hospital mortality were cardiogenic shock (41.6% v 4.0% without cardiogenic shock, p < 0.0001), technical success (29.2% with TIMI (thrombolysis in myocardial infarction) flow < 3 v 6.5% with TIMI flow 3, p < 0.0001), age (16.5% > or = 70 years v 6.6% < 70, p < 0.0001), three vessel disease (16.5% v 6.8% with < 3 vessel disease, p < 0.0001), anterior location of infarction (12% v 7.4% without anterior infarction, p < 0.0001), year of inclusion (adjusted OR 0.92 per year, p = 0.011), and volume of primary angioplasty at the hospital (11% for < 20 angioplasty procedures/year v 8.3% for > or = 20/year, p = 0.027) but not the door to angiography time (adjusted OR 1.14 per tertile, p = 0.397). CONCLUSIONS: In current clinical practice in Germany median door to angiography time is quite short (83 (122) minutes). Some patients and hospital factors are independently associated with a longer door to angiography time. Within the observed short in-hospital delays door to angiography time did not influence in-hospital mortality. However, efforts to keep them as short as possible should be continued.

Comparison of different cardiac markers in monitoring percutaneous coronary interventions with frequent use of stents and gpIIbIIIa-antagonists.

Studies from the early 1990s found elevations of creatine kinase (CK) and its isoform CK-MB in 5-30% of patients after PCI, indicating minor myocardial damage. Less is known about the influence of modern improved PCI-techniques on the frequency of elevated cardiac markers and the correlation between different commonly used markers, especially cardiac troponins. From 1997 to 2001, 1486 patients undergoing PCI during the regular working hours were included in the prospective "Ludwigshafen Infarctlet Registry". Myocardial infarction in the past 48 hours was an exclusion criterion. Clinical and procedural data were documented. Follow-up data were obtained from discharge up to one year. PCI-related elevations of troponin T were found in 18%, of total-CK in 11%, of CK-MB in 33% and of myoglobin in 23% of cases. The correlation between the different markers was poor. Compared with troponin T, other markers showed low sensitivity (total-CK 58%, CK-MB 27%, myoglobin 22%) and, especially total-CK, low specificity. Stenting, side branch occlusion or major dissection, complex lesion morphology, gpIIbIIIa-antagonist application, proximal stenosis and unstable angina were independent predictors of an elevated troponin T in multivariate analysis. Due to this weak correlation between more specific and sensitive troponins and the other markers, troponins are preferred in monitoring after PCI. In addition to lesion characteristics, particularly stenting is associated with an increased rate of elevated troponin.

Two year follow-up in 643 patients with non-invasively unexplained syncope and therapy guided by electrophysiologic study.

AIM: Although it has become standard practice to perform electrophysiologic studies in patients with unexplained syncope, limited information exists on prognosis after therapy guided by electrophysiologic studies. METHODS AND RESULTS: Electrophysiologic studies were performed in 643 patients with unexplained syncope. Electrophysiologic studies revealed conduction abnormalities and tachyarrhythmias accounting for syncope in 35% of patients. An ejection fraction 2 s and injury are helpful parameters in predicting a positive electrophysiologic study. There was no difference regarding cumulative 2-year survival rate after therapy guided by positive electrophysiologic study compared to patients with negative electrophysiologic study. The cumulative 2-year survival free-of-syncope rate was significantly higher after therapy guided by electrophysiologic study compared to patients with negative electrophysiologic findings-for patients with organic heart disease (71.3% vs 48.5%, p < 0.001) and patients without disease (91.3% vs. 65.2%, p < 0.001). Using a logistic regression model, a positive electrophysiologic study was associated with a favorable outcome; multiple syncopal events or organic heart disease were associated with an unfavorable outcome. CONCLUSION: The cumulative overall 2-year surival free-of-syncope rate is significantly higher in patients after therapy guided by electrophysiologic study compared to patients with negative electrophysiologic findings.

[Catheter-based rescue of a split pacemaker lead in the pulmonary artery]. / Kathetertechnische Bergung der Innenwendel einer separierten Schrittmacher-Elektrode in der Arteria pulmonalis.

This case report describes a successful catheter-based rescue of a split pacemaker lead in the pulmonary artery-as an unusual reason for pleural effusion. Hemorrhagic pleural effusion was diagnosed 7 months after pacemaker exchange due to battery depletion and lead replacement due to an increase of the stimulation threshold. The reason for the pleural effusion was a splitting of the inactive electrode lead into shaft and inner fragment which was dislocated into the pulmonary artery and micro-perforated. The dislocated lead was retrieved using biopsy forceps and a gooseneck snare. Finally it was capped and fixed. Even in an anatomically difficult position, catheter-based rescue is feasible. Not in all pacemaker lead types is cutting the adapter of the inactive pacemaker leads recommendable.

Effectiveness of the glycoprotein IIb/IIIa antagonist abciximab during percutaneous coronary interventions (PCI) in clinical practice at a single high-volume center.

OBJECTIVE: Randomized controlled trials (RCTs) showed that the glycoprotein (GP) IIb/IIIa antagonist abciximab is able to reduce ischemic complications during percutaneous transluminal coronary interventions (PCIs). Its effectiveness in daily clinical practice in unselected patients remains to be determined. DESIGN, SETTING AND PATIENTS: From 7/1997 until 12/2000, 3310 PCIs were performed at the Heart Center Ludwigshafen. Out of them, 1076 (32.5%) patients were nonrandomly treated with a GP IIb/ IIa antagonist. Patients who were treated with abciximab were matched with patients not treated with abciximab. The matching procedure resulted in 590 pairs of patients. RESULTS: Patients treated with abciximab were more likely to have a history of former PCI (13.7% versus 8.8%, p=0.008) or coronary artery bypass surgery (19.2% versus 12.8%, p=0.003). There were no differences in concomitant diseases, left ventricular function, number of vessels diseased or target vessel. However, patients treated with abciximab had a higher rate of more complex stenosis (> or =B2; 94.4% versus 80.7%, p<0.001) and a longer x-ray exposition (median 486 s versus 422 s, p<0.001). Treatment with abciximab was associated with a significantly lower incidence of the combined endpoint of death, reinfarction or stroke during the hospital stay (2.4% versus 4.4%, p=0.039). This was confirmed after adjustment for confounding parameters (p=0.034). There was no increase in the rate of severe bleeding in the abciximab group (p=0.347). After one year the rates for the combined endpoint were 8.5% in the control group and 6.2% in the abciximab group (univariate analysis, p=0.134; multivariate analysis, p=0.143). CONCLUSION: Treatment with abciximab during PCI in daily clinical practice at a high volume center in patients with a high rate of acute coronary syndromes seems to be as effective as shown in RCTs.

Worldwide utilization of implantable cardioverter/defibrillators now and in the future.

Despite the demonstrated efficacy of implantable cardioverter defibrillators (ICDs) in reducing sudden and total mortality in selected patients, their implantation rates vary greatly between countries. In the United States, implantation rate is 228 implants per million inhabitants compared to only 45 implants per million in Western Europe. The differences in the ICD use may be explained by following factors: manner in which sudden cardiac death is perceived by politicians and physicians (sudden cardiac death is perceived as a "nice way of dying"); differences in indications; physicians' information; prevalence of coronary artery disease; sudden cardiac death survival rates; perceived reliability of alternative treatment (namely antiarrhythmics including amiodarone); economic backgrounds; and health care politics. Furthermore, the cost of this treatment strategy must be considered. This issue has been raised because generalization of ICD use in patients matching clinical characteristics of patients enrolled in the primary prevention trials may represent a significant economic burden to be added to the already overloaded health care system. This low acceptance may not be entirely related to budget constraint but also to the perceived efficacy of ICDs by physicians and health authorities.

Usefulness of a non-invasive scoring system in predicting the outcome of electrophysiologic studies in non-invasively unexplained syncope.

BACKGROUND: An electrophysiologic study is a useful method to clarify the cause of non-invasively unexplained syncope in 18-60% of patients. However, it is invasive with possible procedure-related complications. Therefore, it would be helpful to identify patients in whom an electrophysiologic study is useful for diagnosis of syncope. METHODS: Patients with unexplained syncope were prospectively enrolled in a registry, if an electrophysiologic study was performed. The study group comprised of 643 consecutive patients. RESULTS: The electrophysiologic study revealed conduction abnormalities and tachyarrhythmias accounting for syncope in 35% of patients. Using a logistic regression model, history of injury during syncope (p<0.001), ejection fraction < or =40% (p=0.03), and PR interval >0.2 s (p=0.001) were independent predictors of an abnormal electrophysiologic study. These three clinical and easily measurable variables were entered into a scoring system. The maximal score consisted of 3 points. A score of >1 predicts a positive electrophysiologic study result in more than 70% of patients with non-invasively unexplained syncope. CONCLUSION: Electrophysiologic abnormalities were detected in 35% of patients with unexplained syncope. A history of injury, ejection fraction < or =40% and a PR interval >200 ms were independent predictors for a positive electrophysiologic study.

Prognostic value of non-sustained ventricular tachycardias after acute myocardial infarction in the thrombolytic era: importance of combination with frequent ventricular premature beats.

PURPOSE: of this study was to re-evaluate the association between ventricular arrhythmias and long-term mortality after acute myocardial infarction (AMI) in the thrombolytic era. METHODS: MITRA (maximal individual therapy in patients with AMI) is a multicenter registry of 54 hospitals in Germany investigating patients with AMI. RESULTS: 2420 patients received Holter ECG. Positive Holter ECG was defined: > or =10 ventricular premature beats (VPB)/h, or > or =4 couplets/d, or > or =1 non-sustained ventricular tachycardia (nsusVT)/d, or their combination. Mortality rates (median 17 months) were 6.5% without ventricular arrhythmias, with > or =10 VPB/h 15.2% and with the combination of > or =10 VPB/h plus either > or =4 couplets/d or > or =1 nsusVT/d 23.4%. In multivariate analysis, none of the ventricular arrhythmias alone correlated with mortality. There was a significant association between mortality and the combination of > or =10 VPB/h plus > or =4 couplets/d (OR 2.3) or > or =10 VPB/h plus > or =1 nsusVT/d (OR 2.8). CONCLUSION: Non-sustained VTs are only associated with poor prognosis if combined with frequent VPBs.

[Long-term outcome of AV node modulation in 387 consecutive patients with AV nodal reentrant tachycardia]. / Langzeitergebnisse nach AV-Knoten-Modulation bei 387 konsekutiven Patienten mit AV-Knoten-Reentry-Tachykardie.

UNLABELLED: Aim of this study was to assess the long-term results of AV-node modulation in patients with AV nodal reetrant tachycardia. METHODS: From December 1991 until September 1999, AV node modulation (ablation of the fast pathway or ablation/modification of the slow pathway) was performed in 387 consecutive patients with clinically apparent AV nodal reentrant tachycardia. Follow-up data was available in 95% of patients with a mean of 41 +/- 26 months after ablation. RESULTS: Acute success rate was 97%. During long-term follow-up recurrence rate was 7.4% without any difference between fast and slow pathway ablation. Recurrence occurred in 23% of patients with persistent dual AV node physiology after ablation (modification of the slow pathway) in contrast to 3% without dual AV node physiology (ablation of the slow pathway) (p = 0.002). The presence of a dual AV node physiology after slow pathway modulation was the only predictor of recurrence during long-term follow-up. The complication rate was 5.7%. The incidence of complete heart block was 1% without any difference between fast and slow pathway ablation. CONCLUSIONS: Catheter modulation of the AV node for the treatment of AV nodal reentrant tachycardia is effective and safe. During long-term follow-up, the recurrence rate was low. Modulation of the slow pathway is associated with a significantly higher recurrence rate than ablation of the slow pathway.

[Catheter ablation of ventricular tachycardia in the left ventricular outflow tract beyond the aortic valve]. / Katheterablation einer Kammertachykardie im linksventrikulären Ausflusstrakt oberhalb der Aortenklappe.

This case report describes successful catheter ablation of an ectopic focus in the left ventricular outflow tract just beyond the aortic valve. Extended pace-mapping revealed a focus about 1 cm beneath the origin of the left coronary artery--above the base of the left coronary cusp. During a follow-up of 1 year no further spontaneous episode of ventricular tachycardia was documented. This case report describes an unusual localization of an idiopathic ventricular tachycardia and it demonstrates that radiofrequency catheter ablation can be done even in a critical position.