[Alternating bundle branch block in a supraventricular tachycardia: Which is the mechanism ?].

Functional bundle branch block during a supraventricular tachycardia can be observed with shorter cycle lengths and represent a physiologic response by the specialized intraventricular conduction system to accelerated AV nodal conduction. The present case corresponds to a young patient with exercise induced orthodromic A-V reentrant tachycardia and alternating bundle branch block. This unusual response is explained by the finding obtained during the electrophysiology study.

[Trigeminy of ventricular bigeminy caused by reentrant mechanism: reentry of reentry].

The process that follows an acute myocardial infarction generates an appropriate substrate for the formation of reentry circuits, considered to be the most frequent mechanism of ventricular extrasystoles and tachyarrhythmias. We present the case of a patient with an acute myocardial infarction unusually concurring with ventricular trigeminy coupled to ventricular bigeminated extrasystoles giving rise to a trigeminy sequence over the bigeminy, which indicates the existence of two reentry circuits (reentry of reentry) that trigger ventricular flutter.

[Induction of atrioventricular nodal reentrant tachycardia by radiofrequency application].

Atrioventricular nodal reentrant tachycardia is the most common form of sustained regular narrow QRS complex tachycardia. It is caused by the presence of a dual atrioventricular nodal anatomy and physiology, with a fast and a slow pathway forming a substrate for re-entry. Electrophysiology study confirms the diagnosis when the tachycardia is induced, although in some cases this is not possible.

[Andersen-Tawil syndrome: a review of its clinical and genetic diagnosis with emphasis on cardiac manifestations].

The Andersen-Tawil syndrome is a cardiac ion channel disease that is inherited in an autosomal dominant way and is classified as type 7 of the congenital long QT syndromes. Affected gene is KCNJ2, which forms the inward rectifier potassium channel designated Kir2.1.

Spontaneous termination of ventricular fibrillation in a patient with congenital coronary anomaly.

Sudden death is common in patients with congenital coronary artery anomalies mainly when the left main coronary artery originates from the right coronary sinus. Ventricular fibrillation in these patients is irreversible unless defibrillation can be rapidly performed. We describe a 57-year-old male with an anomalous origin of circumflex and the left anterior descending coronary arteries from the right coronary sinus.

Flecainide suppresses bidirectional ventricular tachycardia and reverses tachycardia-induced cardiomyopathy in Andersen-Tawil syndrome.

Bidirectional ventricular tachycardia (BVT), although a rare arrhythmia in the general population, is frequently observed in patients with Andersen-Tawil syndrome and long QT interval. However, the pharmacologic treatment of this arrhythmia remains unknown. In the present study, we documented the favorable antiarrhythmic action of flecainide in a young woman with sustained BVT and Andersen-Tawil syndrome.

Adrenergic nervous system influences on the induction of ventricular tachycardia.

Background: Sudden cardiac death is a major cause of mortality in western countries and the ventricular tachyarrhythmias are mainly involved in this regard. The adrenergic autonomic nervous system has influences in provoking life-threatening arrhythmias, and the prevention of such arrhythmias with beta-blockers supports this viewpoint. To evaluate the effect of the adrenergic nervous system and some catecholamine-releasing stimuli on the induction of ventricular tachycardia, we decided to explore the occurrence of ventricular tachycardia in patients subjected to three consecutive tests, exercise testing, isoproterenol infusion, and mental stress.