[Torsades de Pointes: a cause of syncope in sinus node dysfunction]. / Torsade de pointes: una causa de síncope en disfunción del nodo sinusal.

Torsade de Pointes (TdP) is an atypical ventricular tachycardia that occurs in the setting of QT interval prolongation which may be an inherited or acquired abnormality. TdP is a recognized complication of bradyarrhythmias, specifically atrioventricular block. However, sinus node dysfunction is a rare cause of syncope associated with TdP. Experimental studies have suggested that the acquired long QTU interval and TdP may be due to bradycardia or pause-dependent early after depolarizations that give rise to triggered activity. This report describes a patient with sinus bradycardia and intermittent AV nodal rhythm induced long QT interval and repetitive syncope related to TdP and successfully treated with temporal and long-term pacing.

[Glycogenosis type II, infantile variant. Report of a case and review of the literature]. / Glucogenosis tipo II variedad infantil. Informe de un caso y revisión de la literatura.

A case of glycogenosis type II infantile onset (Pompe's disease) is presented, and the literature is reviewed in order to establish the basis of the diagnostic suspect. We studied an 8-month old female with muscular weakness--and cardiac failure. The chest X-ray: cardiomegaly; electrocardiogram: PR interval of 0.06 seconds, gigant QRS complexes, biventricular hypertrophy, and the echocardiogram and cineangiography: left ventricle hypertrophy and hypokinesia. The patient died because of refractory heart failure. Histochemical examination demonstrated excessive intracellular accumulation of glycogen. Also, in the muscle, the kidneys and the liver we did not find any alpha 1,4 glucosidase. Then, the diagnosis of glycogenosis type II infantile onset was established. Finally, we conclude that this disease should be suspected in every infant with muscular weakness, cardiac failure, cardiomegaly, electrocardiogram with shortness of PR interval, gigant QRS complexes and biventricular hypertrophy, and that needs to be confirmed by muscle biopsy. At the moment, there has not been reported any case of Pompe's disease in the Mexican literature.