Search

Contains fulltext : 285318.pdf (Publisher’s version ) (Open Access)

Contains fulltext : 285318.pdf (Publisher’s version ) (Open Access)

Let $\mathcal{P}_n$ be the set of all probability mass functions (PMFs) $(p_1,p_2,\ldots,p_n)$ that satisfy $p_i>0$ for $1\leq i \leq n$. Define the minimum expected length function $\mathcal{L}_D :\mathcal{P}_n \rightarrow \mathbb{R}$ such that $\mathcal{L}_D (P)$ is the minimum expected length of a prefix code, formed out of an alphabet of size $D$, for the discrete memoryless source having $P$ as its source distribution. It is well-known that the function $\mathcal{L}_D$ attains its maximum value at the uniform distribution. Further, when $n$ is of the form $D^m$, with $m$ being a positive integer, PMFs other than the uniform distribution at which $\mathcal{L}_D$ attains its maximum value are known. However, a complete characterization of all such PMFs at which the minimum expected length function attains its maximum value has not been done so far. This is done in this paper.

Multicenter FIRM Registry for AF. Introduction: The success of pulmonary vein isolation (PVI) for atrial fibrillation (AF) may be improved if stable AF sources identified by Focal Impulse and Rotor Mapping (FIRM) are also eliminated. The long-term results of this approach are unclear outside the centers where FIRM was developed; thus, we assessed outcomes of FIRM-guided AF ablation in the first cases at 10 experienced centers.

Ablation Effectiveness and Biophysical Parameters Background There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT).

RF Ablation of VT in Chronic Cocaine Users Background Cocaine use is a known but rare cause of cardiac arrhythmias. Ventricular arrhythmias related to cocaine may not respond to antiarrhythmic drugs and may need treatment with radiofrequency ablation. Objectives We describe the clinical and electrophysiological characteristics of cocaine-related ventricular tachycardia (VT) from a multicenter registry. Methods Subjects presenting with VT related to cocaine use and being considered for radiofrequency ablation have been included in the study. Patients who were refractory to maximal medical therapy underwent radiofrequency ablation of the VT. Clinical, procedural variables, efficacy, and safety outcomes were assessed. Results A total of 14 subjects met study criteria (age 44 ± 13, range 18- to 68-year-old with 79% male, 71% Caucasian). MRI showed evidence of scar only in 43% of patients (6/14). The mechanism of VT was focal in 50% (n = 7) and scar related reentry in 50% (n = 7) based on 3D mapping. The mean VT cycle length was 429 ± 96 milliseconds. The site of origin was epicardial in 16% (3/18) of VTs. Most clinical VTs were hemodynamically stable (75%). Mean ejection fraction at the time of admission was 44 ± 14%. Duration of procedure was 289 ± 50 minutes. One subject developed pericardial tamponade requiring drainage. At 18 ± 11 months follow-up, freedom from arrhythmia was seen in 86% (1 case lost to follow-up and 2 died). Conclusion Radiofrequency ablation is not only feasible but also safe and effective in patients who have drug refractory VT related to chronic cocaine use. © 2014 Wiley Periodicals, Inc.

RF Ablation of VT in Chronic Cocaine Users Background Cocaine use is a known but rare cause of cardiac arrhythmias. Ventricular arrhythmias related to cocaine may not respond to antiarrhythmic drugs and may need treatment with radiofrequency ablation. Objectives We describe the clinical and electrophysiological characteristics of cocaine-related ventricular tachycardia (VT) from a multicenter registry. Methods Subjects presenting with VT related to cocaine use and being considered for radiofrequency ablation have been included in the study. Patients who were refractory to maximal medical therapy underwent radiofrequency ablation of the VT. Clinical, procedural variables, efficacy, and safety outcomes were assessed. Results A total of 14 subjects met study criteria (age 44 ± 13, range 18- to 68-year-old with 79% male, 71% Caucasian). MRI showed evidence of scar only in 43% of patients (6/14). The mechanism of VT was focal in 50% (n = 7) and scar related reentry in 50% (n = 7) based on 3D mapping. The mean VT cycle length was 429 ± 96 milliseconds. The site of origin was epicardial in 16% (3/18) of VTs. Most clinical VTs were hemodynamically stable (75%). Mean ejection fraction at the time of admission was 44 ± 14%. Duration of procedure was 289 ± 50 minutes. One subject developed pericardial tamponade requiring drainage. At 18 ± 11 months follow-up, freedom from arrhythmia was seen in 86% (1 case lost to follow-up and 2 died). Conclusion Radiofrequency ablation is not only feasible but also safe and effective in patients who have drug refractory VT related to chronic cocaine use. © 2014 Wiley Periodicals, Inc.

Multicenter FIRM Registry for AF. Introduction: The success of pulmonary vein isolation (PVI) for atrial fibrillation (AF) may be improved if stable AF sources identified by Focal Impulse and Rotor Mapping (FIRM) are also eliminated. The long-term results of this approach are unclear outside the centers where FIRM was developed; thus, we assessed outcomes of FIRM-guided AF ablation in the first cases at 10 experienced centers.

Ablation Effectiveness and Biophysical Parameters Background There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT).

We present a case of a 67-year-old patient with nonischemic cardiomyopathy and recurrent sustained ventricular tachycardia of epicardial origin referred for ablation. Due to two previous episodes of cardiac tamponade secondary to implantable cardioverter-defibrillator lead perforation at the time of device implant, the patient had significant pericardial adhesions making epicardial access and ablation challenging.

Item does not contain fulltext

Item does not contain fulltext

Item does not contain fulltext