In Vivo Findings of a Novel Focal Ablation Catheter: Focused Electric Field Catheter Tip.

Current catheter designs used for radiofrequency (RF) in cardiac tissue achieve limited ablation depth as lesion size is driven heavily by resistive heating at the tissue surface. A catheter with a truncated, dome-shaped tip with a toroidal surface designed for focal RF ablation was recently described. This in vivo study compares lesion characteristics between a second-generation focused electric field (FEF) catheter vs a standard irrigated catheter using RF energy in a beating heart model. We performed in vivo ablations using RF energy with the FEF ablation catheter tip (Focused Therapeutics) and an irrigated Blazer catheter (Boston Scientific) under identical power, duration, and irrigation rates. In addition, RF dosing at high power and duration was examined using the FEF catheter. Intracardiac echocardiography was used to evaluate steam pops and catheter tip angle relative to the tissue surface. Studies were terminal and lesion size was measured following 2,3,5-triphenyltetrazolium chloride staining. Ablations were performed in 6 swine (FEF, n = 31; control, n = 8). FEF ablation lesions (n = 7) were deeper (15.6 ± 2.6 mm vs 7.5 ± 1.9 mm; P < 0.001) and wider (18.4 ± 2.9 mm vs 12.6 ± 2.4 mm; P < 0.001) than lesions delivered with the control irrigated catheter (n = 8) under the same parameters. Thirty-two percent (n = 10 of 31) of lesions delivered from the left ventricle endocardial surface using the FEF catheter were transmural. No steam pops were observed with delivery of FEF lesions (n = 31). The angle of incidence did not significantly affect FEF lesion size. In this in vivo preclinical study, the FEF catheter, which provides focused energy delivery, resulted in significantly larger lesions than the irrigated control catheter without steam pops. Approximately one-third of ablations with the FEF catheter delivered from the endocardial left ventricular surface resulted in transmural lesions.

A Novel Surface Plasmon Resonance Biosensor for the Rapid Detection of Botulinum Neurotoxins.

Botulinum neurotoxins (BoNTs) are Category A agents on the NIAID (National Institute of Allergy and Infectious Diseases) priority pathogen list owing to their extreme toxicity and the relative ease of production. These deadly toxins, in minute quantities (estimated human i.v. lethal dose LD50 of 1-2 ng/kg body weight), cause fatal flaccid paralysis by blocking neurotransmitter release. The current gold standard detection method, the mouse-bioassay, often takes days to confirm botulism. Furthermore, there are no effective antidotes known to reverse the symptoms of botulism, and as a result, patients with severe botulism often require meticulous care during the prolonged paralytic illness. To combat potential bio-terrorism incidents of botulinum neurotoxins, their rapid detection is paramount. Surface plasmon resonance (SPR) is a very sensitive technique to examine bio-molecular interactions. The label-free, real-time analysis, with high sensitivity and low sample consumption makes this technology particularly suitable for detection of the toxin. In this study, we demonstrated the feasibility in an assay with a newly designed SPR instrument for the rapid detection of botulinum neurotoxins. The LOD (limit of detection) of the Newton Photonics (NP) SPR based assay is 6.76 pg/mL for Botulinum Neurotoxin type A Light Chain (BoNT/A LC). We established that the detection sensitivity of the system is comparable to the traditional mouse LD50 bioassay in BoNT/A using this SPR technology.

Reversible 18-FDG-uptake defects on myocardial PET: Is this myocardial resurrection?

Because it can accurately detect preserved glucose metabolism even in the hypoperfused or stunned myocardium, 18-FDG-PET is considered as the gold standard of myocardial viability assessment. In tako-tsubo cardiomyopathy, a presumed condition of stunning, absence of glucose metabolism however is not a marker of death. This sheds a critical light on 18-FDG-PET as a gold standard for viability.

Echocardiographic quantification of myocardial function using tissue deformation imaging, a guide to image acquisition and analysis using tissue Doppler and speckle tracking.

Recent developments in the field of echocardiography have allowed the cardiologist to objectively quantify regional and global myocardial function. Regional deformation (strain) and deformation rate (strain-rate) can be calculated non-invasively in both the left and right ventricle, providing information on regional (dys-)function in a variety of clinical settings. Although this promising novel technique is increasingly applied in clinical and preclinical research, knowledge about the principles, limitations and technical issues of this technique is mandatory for reliable results and for implementation both in the clinical as well as the scientific field. In this article, we aim to explain the fundamental concepts and potential clinical applicability of strain and strain-rate for both tissue Doppler imaging (TDI) derived and speckle tracking (2D-strain) derived deformation imaging. In addition, a step-by-step approach to image acquisition and post processing is proposed. Finally, clinical examples of deformation imaging in hypertrophic cardiomyopathy (HCM), cardiac resynchronization therapy (CRT) and arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) are presented.