Circulation. Arrhythmia and electrophysiology
-
Circ Arrhythm Electrophysiol · Mar 2017
Comparative StudyFascicular Ventricular Tachycardia Originating From Papillary Muscles: Purkinje Network Involvement in the Reentrant Circuit.
Verapamil-sensitive fascicular ventricular tachycardia (FVT) has been demonstrated to be a reentrant mechanism using the Purkinje network as a part of its reentrant circuit. Although the papillary muscles (PMs) are implicated in arrhythmogenic structure, reentrant FVT originating from the PMs has not been well defined. ⋯ Reentrant circuit of verapamil-sensitive FVT can involve the Purkinje network lying around the PMs. PM-FVT is a distinct entity that is characterized by distinctive electrocardiographic characteristics and less sensitivity to verapamil administration compared with common type FVT. Ablation targeting the mid-diastolic Purkinje potentials around the PMs during tachycardia can be effective in suppressing this arrhythmia.
-
Circ Arrhythm Electrophysiol · Mar 2017
Distribution and Prognostic Significance of Fragmented QRS in Patients With Brugada Syndrome.
Fragmented QRS complexes (fQRS) in the right precordial leads are associated with occurrence of ventricular fibrillation (VF) in Brugada syndrome. Recently, epicardial mapping has revealed abnormal electrograms at the right ventricular (RV) outflow tract and inferior region of the right ventricle. fQRS may reflect the extent of the area of abnormal potentials, but whether the distribution of fQRS has prognostic value is not known. ⋯ The distribution of fQRS is associated with prognosis in Brugada syndrome, further supporting the association of fQRS and arrhythmia substrate.
-
Circ Arrhythm Electrophysiol · Mar 2017
Comparative StudyEffects of Late Sodium Current Blockade on Ventricular Refibrillation in a Rabbit Model.
After defibrillation of initial ventricular fibrillation (VF), it is crucial to prevent refibrillation to ensure successful resuscitation outcomes. Inability of the late Na+ current to inactivate leads to intracellular Ca2+ dysregulation and arrhythmias. Our aim was to determine the effects of ranolazine and GS-967, inhibitors of the late Na+ current, on ventricular refibrillation. ⋯ Late Na+ current inhibition during long-duration VF reduces the susceptibility to subsequent refibrillation, partially by mitigating dysregulation of intracellular Ca2+. These results suggest the potential therapeutic use of ranolazine and GS-967 and call for further testing in cardiac arrest models.