Electrical storm after cardiac resynchronization therapy in a patient with nonischemic cardiomyopathy: Signal-averaged vector-projected 187-channel electrocardiogram-based risk stratification for lethal arrhythmia

AbstractWe describe treatment of atrial flutter and electrical storm presenting as incessant ventricular tachycardia (VT) after implantation of a cardiac resynchronization therapy defibrillator (CRT-D) in a patient with dilated cardiomyopathy. No prior arrhythmic event had occurred. Our treatment strategy, including amiodarone administration, was guided in part by signal-averaged vector-projected 187-channel electrocardiogram (SAVP-ECG)-based risk stratification for ventricular arrhythmia. Corrected recovery time (RTc) dispersion and Tpeak-end dispersion were used to evaluate transmural dispersion of repolarization. RTc and Tpeak-end dispersion increased during the period of electrical storm. Values were improved 2 years after CRT-D implantation, and the amiodarone was discontinued. The VT has not recurred despite discontinuation of the antiarrhythmic agent. SAVP-ECG-based risk stratification for ventricular arrhythmia proved useful for the management of antiarrhythmic therapy

Effects of a high-fat diet on the electrical properties of porcine atria

AbstractBackgroundBecause obesity is an important risk factor for atrial fibrillation (AF), we conducted an animal study to examine the effect of a high-fat diet (HFD) on atrial properties and AF inducibility.MethodsTen 8-week-old pigs (weight, 18–23kg) were divided into two groups. For 18 weeks, five pigs were fed a HFD (HFD group) and five were fed a normal diet (control group). Maps of atrial activation and voltages during sinus rhythm were created for all pigs using the EnSite NavX system. Effective refractory period (ERP) and AF inducibility were also determined. When AF was induced, complex fractionated atrial electrogram (CFAE) mapping was performed. At 18 weeks, hearts were removed for comparing the results of histological analysis between the two groups. Body weight, lipid levels, hemodynamics, cardiac structures, and electrophysiological properties were also compared.ResultsTotal cholesterol levels were significantly higher (347 [191–434] vs. 81 [67–88]mg/dL, P=0.0088), and left atrium pressure was higher (34.5 [25.6–39.5] vs. 24.5 [21.3–27.8]mmHg, P=0.0833) in the HFD group than in the control group, although body weight only increased marginally (89 [78–101] vs. 70 [66–91]kg, P=0.3472). ERPs of the pulmonary vein (PV) were shorter (P<0.05) and AF lasted longer in the HFD group than in the control group (80 [45–1350] vs. 22 [3–30]s, P=0.0212). Neither CFAE site distribution nor histopathological characteristics differed between the two groups.ConclusionsThe shorter ERPs for the PV observed in response to the HFD increased vulnerability to AF, and these electrophysiological characteristics may underlie obesity-related AF

Six-Sigma Quality Improvement Approach to Continuous Loop Management

Six Sigma is a quality management method for identifying and eliminating defects and helping companies improve current processes, products, or services. The aim is to streamline the quality control of manufacturing and business processes so that there are no major differences throughout the operation. This paper describes a management model that emerges by overlaying Nonaka's knowledge creation theory over decision-making and value creation processes borrowed from six-sigma quality improvement practices. The resulting Continuous Loop Model (CLM) illustrates how these Japanese and Western concepts and practices work together in harmony to increase the rate of knowledge creation through continuous feedback loops making the firm more agile, adaptable, innovative, and valuable. The results of this study provide empirical data suggesting that firms that successfully cultivate cultures that are strong in fairness, credibility, respect (collectively trust), pride, and camaraderie significantly outperform comparable firms in several key areas; value, operating effectiveness, and growth

Successful catheter ablation of premature ventricular contractions originating from the anterior fascicle of the left bundle branch in a patient with hypertrophic cardiomyopathy

A 73-year-old man with hypertrophic cardiomyopathy was referred for an electrophysiologic study and catheter ablation of premature ventricular contractions (PVCs)/nonsustained ventricular tachycardia (NSVT). The QRS morphology of the PVCs was right bundle branch block with an inferior axis. Transthoracic echocardiography showed left ventricular hypertrophy and a normal left ventricular ejection fraction without any obstruction in the left ventricle (LV). Intracardiac mapping showed that the earliest activation site of the PVCs was within the anterior portion of the basal LV, where a Purkinje potential preceded the QRS onset by 32 ms. Radiofrequency application at that site terminated the PVCs. The PVCs/NSVT did not recur during 10 months of follow-up

Termination of atrial fibrillation by ablation of high-dominant frequency sites adjacent to epicardial adipose tissue

We report an interesting case in which atrial fibrillation (AF) was terminated during ablation of high-dominant frequency (DF) sites covered with epicardial adipose tissue (EAT). High-DF sites are known to be related to the center of focal-firing rotors or local reentry circuits. Therefore, this phenomenon suggests that EAT may be related to the development of dominant rotors maintaining AF

A case of typical atrial flutter causing unexpected advanced atrioventricular block despite lateral cavotricuspid isthmus ablation

Here, we report a case of a 69-year-old patient with paroxysmal atrial fibrillation and inducible typical atrial flutter who required catheter ablation. After pulmonary vein isolation, cavotricuspid isthmus ablation was performed. During ablation at a lateral site of the cavotricuspid isthmus, a spiky potential appeared at the distal electrode of the ablation catheter, and subsequently, a 2:1 atrioventricular (AV) block occurred. Radiofrequency (RF) delivery at the same site caused a similar phenomenon, implying that the spiky potential may reflect a slow pathway potential as an anatomical variant of the rightward extension of the AV node