Shogo Ito

Electrical Storm in Idiopathic Ventricular Fibrillation Is Associated With Early Repolarization

OBJECTIVES This study sought to characterize patients with idiopathic ventricular fibrillation (IVF) who develop electrical storms. BACKGROUND Some IVF patients develop ventricular fibrillation (VF) storms, but the characteristics of these patients are poorly known. METHODS Ninety-one IVF patients (86% male) were selected after the exclusion of structural heart diseases, primary electrical diseases, and coronary spasm. Electrocardiogram features were compared between the patients with and without electrical storms. A VF storm was defined as VF occurring ≥3 times in 24 h and J waves >0.1 mV above the isoelectric line in contiguous leads. RESULTS Fourteen (15.4%) patients had VF storms occurring out-of-hospital at night or in the early morning. J waves were more closely associated with VF storms compared to patients without VF storms: 92.9% versus 36.4% (p < 0.0001). VF storms were controlled by intravenous isoproterenol, which attenuated the J-wave amplitude. After the subsidence of VF storms, the J waves decreased to the nondiagnostic level during the entire follow-up period. Implantable cardioverter-defibrillator therapy was administered to all patients during follow-up. Quinidine therapy was limited, but the patients on disopyramide (n = 3), bepridil (n = 1), or isoprenaline (n = 1) were free from VF recurrence, while VF recurred in 5 of the 9 patients who were not given antiarrhythmic drugs. CONCLUSIONS The VF storms in the IVF patients were highly associated with J waves that showed augmentation prior to the VF onset. Isoproterenol was effective in controlling VF and attenuated the J waves, which diminished to below the diagnostic level during follow-up. VF recurred in patients followed up without antiarrhythmic agents.

Flecainide ameliorates arrhythmogenicity through NCX flux in Andersen-Tawil syndrome-iPS cell-derived cardiomyocytes

Andersen-Tawil syndrome (ATS) is a rare inherited channelopathy. The cardiac phenotype in ATS is typified by a prominent U wave and ventricular arrhythmia. An effective treatment for this disease remains to be established. We reprogrammed somatic cells from three ATS patients to generate induced pluripotent stem cells (iPSCs). Multi-electrode arrays (MEAs) were used to record extracellular electrograms of iPSC-derived cardiomyocytes, revealing strong arrhythmic events in the ATS-iPSC-derived cardiomyocytes. Ca2+ imaging of cells loaded with the Ca2+ indicator Fluo-4 enabled us to examine intracellular Ca2+ handling properties, and we found a significantly higher incidence of irregular Ca2+ release in the ATS-iPSC-derived cardiomyocytes than in control-iPSC-derived cardiomyocytes. Drug testing using ATS-iPSC-derived cardiomyocytes further revealed that antiarrhythmic agent, flecainide, but not the sodium channel blocker, pilsicainide, significantly suppressed these irregular Ca2+ release and arrhythmic events, suggesting that flecainides effect in these cardiac cells was not via sodium channels blocking. A reverse-mode Na+/Ca2+exchanger (NCX) inhibitor, KB-R7943, was also found to suppress the irregular Ca2+ release, and whole-cell voltage clamping of isolated guinea-pig cardiac ventricular myocytes confirmed that flecainide could directly affect the NCX current (INCX). ATS-iPSC-derived cardiomyocytes recapitulate abnormal electrophysiological phenotypes and flecainide suppresses the arrhythmic events through the modulation of INCX.

J-wave syndrome with giant negative T-wave in severely activated arrhythmogenicity on 12-lead electrocardiography

J-wave syndrome is one of the causes for idiopathic ventricular fibrillation (VF), characterized by early repolarization at the end of QRS wave, especially in the inferior leads. A 42-year-old man with focal …

Development of monomorphic ventricular tachycardia in a patient with fever-induced Brugada syndrome

A 50‐year‐old woman visited the emergency department with a high fever due to pneumonia. Incessant monomorphic ventricular tachycardia occurred and was terminated by intravenous lidocaine. Her ECG during sinus rhythm demonstrated ST segment elevation suggestive of Brugada syndrome (BS). An intensive examination could not detect any structural disease, and typical coved‐type ST elevation was unmasked by a pilsicainide injection leading to a diagnosis of BS. An ICD was implanted for secondary prevention of ventricular arrhythmia. The patient has been free from any recurrences of arrhythmia for 3 years.

A subtype of idiopathic ventricular fibrillation and its relevance to catheter ablation and genetic variants

Introduction Idiopathic ventricular fibrillation (VF) develops in structurally normal hearts and comprises various clinical entities. In particular, site-specific premature ventricular complexes (PVCs), such as PVCs originating from the right ventricular outflow tract or left ventricular papillary muscles, have been reported to provoke idiopathic VF. PVCs originating from papillary muscles and the moderator band (MB) in the right ventricle (RV) are also among the causes of ventricular arrhythmias (VAs).

Authors' reply to Ozeke et al.

We thank Dr Ozeke et al .1 for their interest in our manuscript in which we described a case of idiopathic ventricular fibrillation with prominent J-wave augmentation.2 As they mentioned, complete right bundle branch block (CRBBB) sometimes masks the characteristic ECG of Brugada syndromes (BrSs). Our group recently clarified this phenomenon in serial series …

Mitral Regurgitation as the Cause of Atrial Tachycardia – 3-Dimensional Mapping and 3-Dimensional Transesophageal Echocardiography –

Received October 20, 2014; revised manuscript received February 11, 2015; accepted February 19, 2015; released online March 20, 2015 Time for primary review: 32 days Department of Internal Medicine, Division of Cardiovascular Medicine, Kurume University School of Medicine, Kurume, Japan Mailing address: Masatsugu Ohe, MD, PhD, Department of Internal Medicine, Division of Cardiovascular Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan. E-mail: masaax@mint.ocn.ne.jp ISSN-1346-9843 doi: 10.1253/circj.CJ-14-1134 All rights are reserved to the Japanese Circulation Society. For permissions, please e-mail: cj@j-circ.or.jp Mitral Regurgitation as the Cause of Atrial Tachycardia – 3-Dimensional Mapping and 3-Dimensional Transesophageal Echocardiography –