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Design And Evaluation Of A Catheter Contact-Force Controller For Cardiac Ablation Therapy., Daniel Gelman, Allan C Skanes, Mohammad A Tavallaei, Maria Drangova

Medical Biophysics Publications

GOAL: Maintaining a constant contact force (CF) of an ablation catheter during cardiac catheter ablation therapy is clinically challenging due to inherent myocardial motion, often resulting in poor ablation of arrhythmogenic substrates. To enable a prescribed contact force to be applied during ablation, a catheter contact force controller (CCFC) was developed.

METHODS: The system includes a hand-held device attached to a commercial catheter and steerable sheath. A compact linear motor assembly attaches to an ablation catheter and autonomously controls its relative position within the shaft of the steerable sheath. A closed-loop control system is implemented within embedded electronics to enable …

Hyperpolarized 3he Magnetic Resonance Imaging Ventilation Defects In Asthma: Relationship To Airway Mechanics, Del Leary, Sarah Svenningsen, Fumin Guo, Swati Bhatawadekar, Grace Parraga, Geoffrey N Maksym

Medical Biophysics Publications

In patients with asthma, magnetic resonance imaging (MRI) provides direct measurements of regional ventilation heterogeneity, the etiology of which is not well-understood, nor is the relationship of ventilation abnormalities with lung mechanics. In addition, respiratory resistance and reactance are often abnormal in asthmatics and the frequency dependence of respiratory resistance is thought to reflect ventilation heterogeneity. We acquiredMRIventilation defect maps, forced expiratory volume in one-second (FEV1), and airways resistance (Raw) measurements, and used a computational airway model to explore the relationship of ventilation defect percent (VDP) with simulated measurements of respiratory system resistance (Rrs) and reactance (Xrs).MRIventilation defect maps were …