RR interval variability in the evaluation of ventricular tachycardia and effects of implantable cardioverter defibrillator therapy.

Background: An implantable cardioverter defibrillator (ICD) is the most reliable therapeutic device for preventing sudden cardiac death in patients with sustained ventricular tachycardia (VT). Regarding its effectiveness, targeted VT is defined based on the tachyarrhythmia cycle length. However, variations in RR interval variability of VTs may occur.

Inappropriate implantable cardioverter defibrillator shocks-incidence, effect, and implications for driver licensing.

Purpose: Patients with implantable cardioverter defibrillators (ICDs) have an ongoing risk of sudden incapacitation that may cause traffic accidents. However, there are limited data on the magnitude of this risk after inappropriate ICD therapies. We studied the rate of syncope associated with inappropriate ICD therapies to provide a scientific basis for formulating driving restrictions.

Superior Rhythm Discrimination With the SmartShock Technology Algorithm - Results of the Implantable Defibrillator With Enhanced Features and Settings for Reduction of Inaccurate Detection (DEFENSE) Trial.

Background: Shocks delivered by implanted anti-tachyarrhythmia devices, even when appropriate, lower the quality of life and survival. The new SmartShock Technology(SST) discrimination algorithm was developed to prevent the delivery of inappropriate shock. This prospective, multicenter, observational study compared the rate of inaccurate detection of ventricular tachyarrhythmia using the SST vs.

Various mechanisms and clinical phenotypes in electrical short circuits of high-voltage devices: report of four cases and review of the literature.

Aims: An electrical short circuit is a rare complication in a high-voltage implantable cardioverter-defibrillator (ICD). However, the inability of an ICD to deliver appropriate shock therapy can be life-threatening.

Methods And Results: During the last 2 years, four cases of serious complications related to an electrical short circuit have been reported in Japan.

Feasibility evaluation of a remote monitoring system for implantable cardiac devices in Japan.

The number of implanted cardiac devices has been growing steadily over the last several years. Systems to monitor device data remotely have been introduced with the goal of reducing follow-up burden for both patients and physicians. Since the introduction of telemedicine depends greatly on the situations that are unique to each country, the acceptance of cardiac device remote monitoring in Japan was analyzed.

An autopsy case of the rupture of a giant aneurysm in a saphenous vein graft: 18 years after CABG.

The saphenous vein is a widely used blood vessel for arterial bypass procedures. Failures of saphenous vein aortocoronary bypass grafts are predominantly the result of subsequent vein graft atherosclerotic disease. Rarely saphenous vein grafts undergo aneurysmal degeneration.

Nifekalant versus lidocaine for in-hospital shock-resistant ventricular fibrillation or tachycardia.

Objective: To compare the efficacy and safety of nifekalant, a pure class III anti-arrhythmic drug, and lidocaine in patients with shock-resistant in-hospital ventricular fibrillation (VF) or ventricular tachycardia (VT).

Patients And Methods: Between August 2005 and March 2008, we conducted a prospective, two-arm, cluster observational study, in which participating hospitals were pre-registered either to the nifekalant arm or the lidocaine arm. Patients were enrolled if they had in-hospital VF or VT resistant to at least two defibrillation shocks.

Spatial and topologic distribution of verapamil-sensitive atrial tachycardia originating from the vicinity of the atrioventricular node.

Background: Little information exists regarding the precise distribution of verapamil-sensitive atrial tachycardia originating from the vicinity of the atrioventricular node (V-AT).

Methods: In 12 patients with V-AT, we examined the spatial and topologic distribution of tachycardia origin relative to the His bundle (HB) site. The V-AT origin was divided into six areas: anterior (A-HB), posterior (P-HB), superior (S-HB), inferior (I-HB), lateral (L-HB), and septal (SP-HB) portion of HB catheter.

Impact of right atrial-left ventricular dual-chamber permanent pacing in patients with severely symptomatic hypertrophic obstructive cardiomyopathy.

Background: Effective alternatives to surgical myectomy for patients with symptomatic hypertrophic obstructive cardiomyopathy (HOCM) remain unestablished. Dual-chamber (DDD) pacing was evaluated in these patients using right atrial (RA) and epicardial left ventricular (LV) leads.

Methods And Results: In 6 patients with HOCM refractory to medical therapy and conventional RA-right ventricular (RV) DDD pacing, we implanted DDD pacemakers using RA and epicardial LV leads.

Improved hypertrophic obstructive cardiomyopathy by left ventricular apex epicardial pacing.

We report a case of severe hypertrophic obstructive cardiomyopahy (HOCM) that was markedly improved by left ventricular (LV) apex epicardial pacing. A 55-year-old woman with HOCM had suffered from dyspnea. Cardiac catheter examination showed a resting pressure gradient across the LV outflow tract of 198 mmHg despite combined medication.

Anterograde slow pathway is not the same as retrograde slow pathway conducted in the reverse direction in patients with uncommon atrioventricular nodal reentrant tachycardia.

Introduction: The aim of this study was to examine the location of anterograde and retrograde slow pathways in 16 patients with uncommon atrioventricular nodal reentrant tachycardia (AVNRT), including the fast-slow form in 10, slow-slow form in 5, and both fast-slow and slow-slow forms in 1.

Methods And Results: Patients were divided into two groups according to the approach used for slow pathway ablation in the initial radiofrequency catheter ablation (RFCA): one approach used earliest atrial activation during tachycardia (ES group, n = 9), and the other used a slow potential during sinus rhythm (SP group, n = 7). When the initial RFCA failed to eliminate slow pathway conduction in the ES group, an additional RFCA guided by a slow potential was performed.

Spontaneous regression of focal nodular hyperplasia of the liver.

Focal nodular hyperplasia (FNH) of the liver is a rare benign lesion that probably reflects a local hyperplastic response of hepatocytes to a vascular abnormality. Currently, the natural history of the disease remains largely unknown. We present a patient with FNH of the liver who was followed up for 4 years.

Prevention of ventricular fibrillation by cilostazol, an oral phosphodiesterase inhibitor, in a patient with Brugada syndrome.

We report the case of 67-year-old man with Brugada syndrome, in whom daily episodes of ventricular fibrillation (VF) occurred every early morning for 4 days. The episodes of VF were completely prevented by an oral administration of cilostazol, a phosphodiesterase inhibitor. This effect was confirmed by the on-and-off challenge test, in which discontinuation of the drug resulted in recurrence of VF and resumption of the drug again prevented VF.