Cardiorespiratory-gated cardiac proton radiotherapy using a novel ultrasound guidance system.

Cardiac stereotactic body radiotherapy is a promising noninvasive treatment for patients with refractory ventricular tachycardia. With the aim to prove feasibility of a novel image guided radiotherapy and heart motion gating device, cardiac proton radiotherapy was performed using a porcine model. Using a novel adaptation of γ - H2AX tissue staining techniques, we have been able to localize a radiation beam in large animal tissue to assess targeting accuracy within a defined field.

Effect of additional dimensions and views in the echocardiographic determination of 3-dimensional left ventricular volume in myxomatous mitral valve disease in dogs.

Background: Left ventricular (LV) volumes can be calculated from various linear, monoplane, and multiplane echocardiographic methods, and the same method can be applied to different imaging views. However, these methods and their variations have not been comprehensively evaluated against real-time 3-dimensional echocardiography (RT3D).

Hypothesis/objectives: To identify the LV volumetric approaches that produce the least bias and the best agreement with RT3D, and to assess interoperator reproducibility between an experienced and an inexperienced operator.

Preclinical Experience Using 4D Intracardiac Echocardiography to Guide Cardiac Electrophysiology Procedures.

Introduction: Intracardiac echocardiography (ICE) is an essential imaging modality for electrophysiology procedures, allowing intraprocedural monitoring, real-time catheter manipulation guidance, and visualization of complex anatomic structures. Four-dimentional (4D) ICE is the next stage in the evolution of the technology, permitting 360° rotation of the imaging plane, simultaneous multiplanar imaging, and volumetric acquisition, similar to transesophageal echocardiography (TEE). In this study, we report our experience with a novel 4D ICE catheter (NuVision, Biosense Webster) in structural electrophysiology procedures and difficult ventricular ablations in a swine preclinical model.

High-density versus point-by-point electroanatomical activation mapping of a cranial vena cava tachycardia in a dog.

A seven-year-old, male intact Newfoundland was referred for catheter ablation of supraventricular tachycardia. Activation mapping was performed using an electroanatomical mapping system to visualize the activation wavefront in a color-coded fashion on an anatomical shell. Atrial flutter with an early-meets-late signal (i.

Design, Testing, and Validation of a Soft Robotic Sensor Array Integrated with Flexible Electronics for Mapping Cardiac Arrhythmias.

Cardiac mapping is a crucial procedure for diagnosing and treating cardiac arrhythmias. Still, current clinical techniques face limitations including insufficient electrode coverage, poor conformability to complex heart chamber geometries, and high costs. This study explores the design, testing, and validation of a 64-electrode soft robotic catheter that addresses these challenges in cardiac mapping.

Treating Stubborn Cardiac Arrhythmias-Looking Toward the Future.

As animals can develop significant side effects or remain refractory while on antiarrhythmic medical therapy for tachyarrhythmias, interventional therapies are progressively being explored. This review will highlight the principles and utilities of implantable cardioverter-defibrillators, electrophysiological mapping and catheter ablation, three-dimensional electroanatomical mapping, and stereotactic arrhythmia radiotherapy. In particular, three-dimensional electroanatomical mapping is emerging as an adjunct electrophysiology tool to facilitate activation, substrate, and pace mapping for intuitive analysis of complex tachyarrhythmias.

Creating Stretchable Electronics from Dual Layer Flex-PCB for Soft Robotic Cardiac Mapping Catheters.

The authors present in this study the development of a novel method for creating stretchable electronics from dual-layer flex printed circuit boards (flex-PCBs) as a platform for soft robotic sensor arrays (SRSAs) for cardiac voltage mapping applications. There is a crucial need for devices that utilize multiple sensors and provide high performance signal acquisition for cardiac mapping. Previously, our group demonstrated how single-layer flex-PCB can be postprocessed to create a stretchable electronic sensing array.

Echocardiographic evaluation of regurgitant fraction in dogs with subclinical myxomatous mitral valve disease: Method comparison, effects of pimobendan, and reproducibility.

Introduction/objectives: To evaluate regurgitant fraction (RF) using Simpson's method of discs to estimate total stroke volume (RF) and using Motion-mode to estimate total stroke volume (RF) in dogs with subclinical myxomatous mitral valve disease (MMVD). We also sought to evaluate the effects of pimobendan on RF, and to determine the reproducibility of RF and RF.

Animals, Materials, And Methods: Echocardiography was performed on 57 dogs with MMVD (30 stage B1 and 27 stage B2).

Three-dimensional activation maps of sinus rhythm and focal atrial tachycardia in a dog.

A five-year-old, female-spayed boxer was referred for frequent and medically refractory paroxysmal supraventricular tachycardia. Diagnostic evaluation found no underlying structural heart or systemic diseases. Three-dimensional electroanatomical mapping and radiofrequency ablation were pursued.

Feasibility of electroanatomic mapping and radiofrequency catheter ablation in Boxer dogs with symptomatic ventricular tachycardia.

Background: Treatment for Boxers with ventricular tachycardia (VT) is limited. Electroanatomic mapping (EAM) facilitates identification of arrhythmogenic substrate for radiofrequency catheter ablation (RFCA).

Objective: Describe the use of EAM to guide RFCA in Boxers with VT.

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

Three-dimensional electroanatomic mapping and radiofrequency catheter ablation of ventricular arrhythmia in a dog without structural heart disease.

A 1.5-year-old, female-spayed mix-breed dog was presented with recurrent episodes of shaking and excessive panting attributed to drug-refractory ventricular arrhythmia (VA) characterized predominantly by incessant periods of ventricular bigeminy. The VA had a narrow QRS morphology, suggestive of an origin near the His bundle or fascicular system.

Isolated critical epicardial arrhythmogenic substrate abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy and ventricular tachycardia.

Background: Ventricular tachycardia (VT) substrate abnormalities in arrhythmogenic right ventricular cardiomyopathy (ARVC) typically involve both the right ventricular (RV) endocardium (ENDO) and epicardium (EPI).

Objective: The purpose of this study was to examine the prevalence, electrophysiological features, and outcomes of catheter ablation of VT in patients with isolated epicardial substrate (IES) abnormalities.

Methods: We studied 71 consecutive patients with VT who met Task Force criteria for ARVC and underwent detailed ENDO and EPI mapping.

Aorto-left atrial fistula secondary to infective aortic endocarditis and endarteritis in a cat with valvular aortic stenosis.

A cat previously diagnosed with valvular aortic stenosis developed acute respiratory distress. A new continuous heart murmur was noted on physical exam. Echocardiographic examination revealed vegetative lesions on the aortic valve and continuously shunting blood flow from the aorta into the left atrium.

Anomalous Left-to-Right Shunting Vessel between the Ascending Aorta and Right Pulmonary Artery and Concurrent Left Peripheral Pulmonary Artery Stenosis in a Dog.

• Atypical appearance of continuous shunting vessel warrants further characterization. • A type III PFAA has not been previously suspected in dogs. • Unilateral pulmonary artery stenosis may not impose significant pressure overload.

Reproducibility of echocardiographic indices of left atrial size in dogs with subclinical myxomatous mitral valve disease.

Background: Reliability of echocardiographic measurements of left atrial (LA) size, an important marker of disease severity, has not been reported in dogs with myxomatous mitral valve disease (MMVD).

Objectives: To define and compare reliability of left atrial dimension/diameter (LAD), LAD indexed to aortic valve diameter (LAD/AoD), left atrium-to-aortic root ratio (LA/Ao), left atrial volume acquired from a right parasternal long-axis (LAV ), and left apical view (LAV ) in dogs with subclinical MMVD.

Animals: Nine dogs with subclinical MMVD.

Echocardiographic assessment of right heart size and function in dogs with pulmonary valve stenosis.

Introduction/objectives: We sought to determine the prevalence and clinical significance of right heart remodeling and right ventricular (RV) dysfunction in dogs with pulmonary valve stenosis (PS). We also sought to evaluate repeatability of several measurements of severity of PS, right heart size, and RV function in dogs with PS.

Animals, Materials And Methods: Several indices of right atrial (RA) size and RV size and function were prospectively evaluated in 48 dogs with PS.

Severity of Mitral Valve Degeneration Is Associated with Chromosome 15 Loci in Whippet Dogs.

Mitral valve degeneration (MVD) is the most common form of heart disease in dogs, frequently leading to left-sided congestive heart failure and cardiac mortality. Although breed-specific disease characteristics and overrepresentation point towards a genetic origin for MVD, a causative mutation and complete molecular pathogenesis are unknown. Whippet dogs are overrepresented in incidence of MVD, suggesting an inherited component in this breed.