testing-efficacy-pharmacological-agents-pericardial-target-delivery

Testing the Efficacy of Pharmacological Agents in a Pericardial Target Delivery Model in the Swine

To date, many pharmacological agents used to treat or prevent arrhythmias in open-heart cases create undesired systemic side effects. For example, ...

University of Minnesota

This paper describes how the Atlas of Human Cardiac Anatomy website can be used to improve cardiac device design throughout the process of development. The Atlas is a free-access website featuring novel images of both functional and fixed human cardiac anatomy from over 250 human heart specimens. This website provides numerous educational tutorials on anatomy, physiology and various imaging modalities. For instance, the 'device tutorial' provides examples of devices that were either present at the time of in vitro reanimation or were subsequently delivered, including leads, catheters, valves, annuloplasty rings and stents. Another section of the website displays 3D models of the vasculature, blood volumes and/or tissue volumes reconstructed from computed tomography and magnetic resonance images of various heart specimens. The website shares library images, video clips and computed tomography and MRI DICOM files in honor of the generous gifts received from donors and their families.

The benefits of the Atlas of Human Cardiac Anatomy website for the design of cardiac devices.

Catheter perforations remain a major clinical concern during ablation procedures for treatment of atrial arrhythmias and may lead to life-threatening cardiac tamponade. Radiofrequency (RF) ablation alters the biomechanical properties of cardiac tissue, ultimately allowing for perforation to occur more readily. Studies on the effects of cryoablation on perforation force as well as studies defining the perforation force of human tissue are limited.

Optimal contact forces to minimize cardiac perforations before, during, and/or after radiofrequency or cryothermal ablations.

This study focused on how catheter size affects transseptal puncture, what transseptal indication means, and whether the swine model is predictive for humans.

Tissue properties of the fossa ovalis as they relate to transseptal punctures: a translational approach.

Changes in cardiac tissue properties following the application of various ablation modalities may lead to the development of an array of associated complications. The application of either radio frequency (RF) or cryothermal ablations will alter the biomechanical properties of various cardiac tissues in a differential manner; in some cases, this may be attributable to increased incidences of cardiac tamponade, pulmonary vein stenosis, and/or atrial-esophageal fistula. Thus, a greater understanding of the underlying changes in tissue properties induced by ablative therapies will ultimately promote safer and more efficacious procedures. The effects of applied RF or cryothermal energies on the biomechanical properties of the pulmonary vein, left atrial, or right atrial samples ([Formula: see text]) were examined from fresh excised porcine ([Formula: see text]) and donated human tissue ([Formula: see text]). RF ablations were found to reduce the tensile strength of the porcine cardiac specimens ([Formula: see text]), and a similar trend was noted for human samples. Cryoablations did not have a significant impact on the tissue properties compared with the untreated tissue specimens. Locational and species differences were also observed in this experimental paradigm ([Formula: see text]. Incorporating these findings into cardiac device design and computational modeling should aid to reduce the risks of complications associated with tissue property changes resulting from cardiac ablative procedures.

The Effects of Radiofrequency or Cryothermal Ablation on Biomechanical Properties of Isolated Human or Swine Cardiac Tissues.

In vitro isolated heart preparations are valuable tools for the study of cardiac anatomy and physiology, as well as for preclinical device testing. Such preparations afford investigators a high level of hemodynamic control, independent of host or systemic interactions. Here we hypothesize that recovered human and swine heart-lung blocs can be reanimated using a clear perfusate and elicit viable cardiodynamic and pulmonic function. Further, this approach will facilitate multimodal imaging, which is particularly valuable for the study of both functional anatomy and device-tissue interactions. Five human and 18 swine heart-lung preparations were procured using techniques analogous to those for cardiac transplant. Specimens were then rewarmed and reperfused using modifications of a closed circuit, isolated, beating and ventilated heart-lung preparation. Positive pressure mechanical ventilation was also employed, and epicardial defibrillation was applied to elicit native cardiac sinus rhythm. Videoscopy, fluoroscopy, ultrasound, and infrared imaging were performed for anatomical and experimental study.

Article	Year
The benefits of the Atlas of Human Cardiac Anatomy website for the design of cardiac devices. Expert review of medical devices\| PubMed ID: 24195457	2013
Optimal contact forces to minimize cardiac perforations before, during, and/or after radiofrequency or cryothermal ablations. Heart rhythm : the official journal of the Heart Rhythm Society\| PubMed ID: 25461502	2015
Tissue properties of the fossa ovalis as they relate to transseptal punctures: a translational approach. Journal of interventional cardiology\| PubMed ID: 25689553	2015
The Effects of Radiofrequency or Cryothermal Ablation on Biomechanical Properties of Isolated Human or Swine Cardiac Tissues. IEEE journal of translational engineering in health and medicine\| PubMed ID: 27170912	2016
The novel in vitro reanimation of isolated human and large mammalian heart-lung blocs. BMC physiology\| PubMed ID: 27259478	2016

Stephen Quallich

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