Utilidad de la adenosina para evidenciar bloqueo auriculoventricular avanzado paroxÝstico como causa de sÝncope / Usefulness of adenosine to detect advanced paroxysmal atrioventricular block as a cause of syncope

We present the case of a 66 years old man with recurrent episodes of syncope, up to three times during the last two months without previous symptoms. An ECG after the syncope showed a bilateral block (left anterior fascicle block and right bundle branch block) and first grade atrioventricular block. The exercise test did not demonstrate either AV conduction disorders or tachyarrhythmia episodes. Holter monitoring showed premature ventricular complexes; tilt testing and carotid sinus massage were normal. The electrophysiologic study revealed no alteration in the conduction system. Throughout atrial and ventricular stimulation documented no tachyarrhythmias. However, intravenous administration of 12 mg of adenosine induced complete AV infra-His block with ventricular asystolia of 7.2 sec duration. Adenosine testing can identify patients with syncope due to paroxysmal AV block even when the electrophysiological findings and other conventional tests are not conclusive.

Desenmascaramiento del "síndrome de Brugada" con propafenona endovenosa / Disclosure of

We present the case of a woman with familial antecedents of a brother who died suddenly at the age of 39 years, and an other with Brugada syndrome. The ECG had not shown the typical pattern of the Brugada syndrome. Based on these antecedents, we decided to perform a pharmacological test with endovenous propafenone, which revealed the electrocardiographic alterations at 10 min after the administration. This is the first case in our knowledge in which endovenous propafenone manifested a concealed Brugada syndrome.