ABSTRACT
We report a 37-year-old man with type I second-degree atrioventricular (AV) block (atypical Wenckebach's periodicity) referred to our department for pacemaker implantation because of an episode of syncope. After exhaustive evaluation, including electrophysiological test, in which Wenckebach's cycles with block within the AV node was demonstrated, syncope was considered to be neurally mediated. Head-up tilt testing with sublingual isosorbide dinitrate was positive. The decrease in atrial rate at the beginning of the vasovagal reaction was not immediately accompanied by a depressed AV node conduction. Only at the moment of syncope did incomplete AV block appear. This observation illustrates (1) a neurally mediated origin of syncope in a patient with chronic AV block, and (2) the different time-course responses of the sinus and AV nodes to autonomic tone.
Subject(s)
Dizziness/diagnosis , Electrocardiography/methods , Heart Block/complications , Heart Block/diagnosis , Syncope, Vasovagal/diagnosis , Syncope, Vasovagal/etiology , Vision, Low/diagnosis , Adult , Chronic Disease , Dizziness/etiology , Humans , Male , Vision, Low/etiologyABSTRACT
A 37-year-old man with Brugada syndrome and dynamic changes of the ST-segment morphology observed after an episode of aborted sudden death is described. On admission, after 3 syncopal episodes during nighttime, his electrocardiogram showed right bundle branch block (RBBB) with a J-point elevation of 0.6 mV in lead V 2 . Changes observed in the following days included a diminished J-point elevation and intermittent "saddle-back" type of morphology. During a previous 2-year follow-up, intermittent, complete, acceleration-dependent RBBB was documented. Right ventricular intracavitary tracings showed an RS pattern with a broad S wave in the unipolar electrogram; the time of onset of intrinsic deflection in this electrogram was 60 milliseconds. To our knowledge, this is the first report of an intracavitary demonstration of complete RBBB in Brugada syndrome.
Subject(s)
Bundle-Branch Block/complications , Electrocardiography , Heart Arrest/therapy , Adult , Arrhythmia, Sinus/etiology , Bradycardia/etiology , Bundle-Branch Block/therapy , Defibrillators, Implantable , Electrocardiography/classification , Electrocardiography/methods , Follow-Up Studies , Heart Ventricles/physiopathology , Humans , Male , Syncope/etiology , SyndromeABSTRACT
Se estudio el electrocardiograma de 37 pacientes con discordancia atrio-ventricular (DAV), divididos en dos grandes grupos: I)situs solitus y II) situs inversus, con: a) sin defectos asociados y b) con defectos asociados. Se concluye: 1) Que el primer vector de activacion ventricular dirigido en el mismo sentido que el de activacion atrial, constituye signo fundamental de diagnostico; 2) la preponderancia del ventriculo anatomicamente derecho inclina al diagnostico de que no existen defectos asociados; 3) la presencia de hipertrofia biventricular obliga a suponer la asociacion de defectos; 4) la desviacion de AQRS y el acortamiento en la duracion de la sistole electrica local contribuyen al diagnostico de sobrecarga ventricular y ventriculo hipertrofiado; 5) la presencia de bloqueio de rama derecha del haz de His no esta en relacion con el grado de sobrecarga; 6) las alteraciones primarias de la repolarizacion son signos univocos de sufrimiento miocardico
