Osypka (Germany)

Atrial fibrillation (AF) is common in heart failure (HF) and negatively impacts outcomes. The role of ablation-based rhythm control in patients with AF and HF with preserved (HFpEF) or mildly reduced ejection fraction (HFmrEF) is not known. The CABA-HFPEF-DZHK27 (CAtheter-Based Ablation of atrial fibrillation compared to conventional treatment in patients with Heart Failure with Preserved Ejection Fraction) trial will determine whether early catheter ablation for AF can prevent adverse cardiovascular outcomes in patients with HFpEF or HFmrEF. CABA-HFPEF-DZHK27 (NCT05508256) is an investigator-initiated, prospective, randomized, open, interventional multicentre strategy trial with blinded outcome assessment. Approximately 1548 patients with paroxysmal or persistent AF diagnosed within 24 months prior to enrolment and HFpEF or HFmrEF will be randomized to early catheter ablation within 4 weeks after randomization or to usual care. All patients receive anticoagulation, rate control, and HF management according to current guideline recommendations. Usual care can include rhythm control in symptomatic patients. Patients will be followed until the end of the trial for the primary outcome, a composite of cardiovascular death, stroke, and total unplanned hospitalizations for HF or acute coronary syndrome. The safety outcome comprises complications of catheter ablation and death. The trial is powered for a rate ratio of 0.75 (two-sided alpha = 0.05, 1-beta = 0.8). CABA-HFPEF-DZHK27 will define the role of systematic and early catheter ablation in patients with AF and HFpEF or HFmrEF.

Transthoracic electrical bioimpedance (TEB) measurement for acquiring of hemodynamic parameters e.g. stroke volume (SV) and cardiac output (CO) becomes commonly used. For precise and reliable measurement, a good understanding of the measurement system is needed to provide robust electrode placement, reproducible results, and large signal amplitudes. We propose an evaluation by MRI based human phantom with FEM based quasi-static solver for electrode placement in bioimpedance measurement. Placements according to Osypka, Cheetah and Bernstein et al. were simulated and compared with measurements taken from a (real) human subject. As a parameter for evaluation of signal quality, the percentage of current passing through the descending aorta from the overall injected current is measured. The placement according to Osypka results in 1.46 % of current flow through the descending aorta (Cheetah placement 1.12 %, Bernstein et al. placement 0.877 %) for the male human phantom DUKE. The simulation was compared with a real human subject (with comparable age, height, weight) by calculating the baseline impedance (Z0). The simulation seems to fit at best with Osypka placement, where the deviation between simulated baseline impedance and real human subject is 19.9 % (deviation for Cheetah 34.1 %, deviation for Bernstein 62.5 %). The simulation with MRI based human phantoms seems to be a very good basis for further investigations of current injection and bioimpedance measurement comprehension.

In this article, most of the present or available in the near future left atrial appendage (LAA) occlusion devices are discussed in terms of structure of the devices and principle technique for implantation. Thus, the Watchman™ device from Boston, the Amulet™ device from Abbot, the Lambre™ device from Lifetech, the Occlutech® device from Occlutech®, and the WaveCrest® device from Biosense Webster (former Coherex) are discussed. The systems differ in terms of the concept of occlusion. Several devices consist of only one part (Watchman™ and Occlutech®) that is implanted in the body, ending up in the orifice of the LAA. Others like the Amulet™ or Lambre™ device have an additional disc covering the orifice of the LAA from the left atrial side. The distal anchoring system is implanted first in the body of the LAA; thereafter, the disc is placed upon the orifice. With the WaveCrest® device, covering of the orifice is performed as the first step followed by rolling in the anchoring system to fix the device to the body of the LAA.

Atrial fibrillation (AF) is the most common sustained arrhythmia in the general population. As an age-related arrhythmia AF is becoming a huge socio-economic burden for European healthcare systems. Despite significant progress in our understanding of the pathophysiology of AF, therapeutic strategies for AF have not changed substantially and the major challenges in the management of AF are still unmet. This lack of progress may be related to the multifactorial pathogenesis of atrial remodelling and AF that hampers the identification of causative pathophysiological alterations in individual patients. Also, again new mechanisms have been identified and the relative contribution of these mechanisms still has to be established. In November 2010, the European Union launched the large collaborative project EUTRAF (European Network of Translational Research in Atrial Fibrillation) to address these challenges. The main aims of EUTRAF are to study the main mechanisms of initiation and perpetuation of AF, to identify the molecular alterations underlying atrial remodelling, to develop markers allowing to monitor this processes, and suggest strategies to treat AF based on insights in newly defined disease mechanisms. This article reports on the objectives, the structure, and initial results of this network.

Article Exclusion of Adverse Hemodynamic Programming in Cardiac Resynchronization Therapy was published on September 7, 2013 in the journal Biomedical Engineering / Biomedizinische Technik (volume 58, issue SI-1-Track-I).

Introduction Long-term monitoring of malign hypertension patients is important for physicians to prescribe appropriate medical treatment in order to reduce the incidence of secondary consequences such as stroke, kidney failure or heart insufficiency. However, current devices are not suited for long-term blood-pressure measurement. In order to address this need, we developed and conducted in-vivo tests on a novel, fully-implantable, wireless blood-pressure monitoring system. Methods The monitoring system was tested for six months in 12 chronic ovine models. The sensor was implanted with X-raycontrol in the femoral artery by means of a dedicated sheath (PASIS). Reference measurements were recorded with industry standard pressure sensors post implantation. Position and proper functioning of the sensor were controlled via regular readout measurements and CTs. At the end of each trial, a histological examination was conducted. Results Chronic in-vivo studies revealed that blood pressure measurement over a period of six months was possible with the novel implantable sensor system. Stable pressure histories were recorded. However, the mechanical resilience of the sensor system requires improvement. The in-vivo tests in the femoral artery of sheep produced high stress on the sensors system. Several implanted systems became inoperative despite efforts to stiffen the sensor-cable. The histological analysis detected no thrombi, however mild ingrowth was observed in several cases. Conclusion The results of the chronic in-vivo tests on the novel implantable blood-pressure monitoring system were encouraging. Improvements need to be made regarding the mechanical resilience of the system and the coating needs to investigated to reduce ingrowth-behavior. Additional trials at a modified implantation spot will be conducted in order to reveal further insights regarding system performance.