Severe infantile-onset cardiomyopathy associated with a homozygous deletion in desmin.

Desminopathy is a genetically heterogeneous disorder with autosomal dominant pattern of inheritance in most affected families; the age of disease onset is on average 30 years. We studied a patient with a history of recurrent episodes of syncope from infancy who later developed second-degree AV block and restrictive cardiomyopathy; she subsequently suffered several episodes of ventricular tachyarrhythmia requiring implantation of bicameral defibrillator. Neurological examination revealed rapidly progressive bilateral facial weakness, winging of the scapulae, symmetric weakness and atrophy of the trunk muscles, shoulder girdle and distal muscles of both upper and lower extremities. Muscle biopsy demonstrated signs of myofibrillar myopathy with prominent subsarcolemmal desmin-reactive aggregates. Molecular analysis identified a homozygous deletion in DES resulting in a predicted in-frame obliteration of seven amino acids (p.R173_E179del) in the 1B domain of desmin. We describe the youngest known desminopathy patient with severe cardiomyopathy and aggressive course leading to the devastation of cardiac, skeletal and smooth musculature at an early age.

[Electrocardiographic findings typical of Brugada syndrome unmasked by cocaine consumption]. / Patrón electrocardiográfico de Brugada desenmascarado por consumo de cocaína.

Brugada syndrome is characterized by the presence of right bundle branch block on electrocardiography and by ST-segment elevation in the right precordial leads (V1-V3), by the absence of structural cardiac abnormalities, and by episodes of syncope or sudden death. On occasion, diagnosis is made difficult by temporary normalization of the ECG. The condition can be unmasked by potent sodium channel blockers, such as flecainide. Our patient presented with a Brugada syndrome-type ECG after intake of a large amount of cocaine.

Patrón electrocardiográfico de Brugada desenmascarado por consumo de cocaína / Electrocardiographic findings typical of brugada syndrome unmasked by cocaine consumption

El diagnóstico del síndrome de Brugada se caracteriza por la presencia en el electrocardiograma (ECG) de bloqueo de rama derecha y elevación del segmento ST en las derivaciones precordiales derechas, ausencia de enfermedad cardíaca estructural y episodios de síncope o de muerte súbita. En ocasiones, el diagnóstico se encuentra dificultado por la normalización transitoria del ECG y puede ser desenmascarado por bloqueadores de los canales de sodio, como la flecainida. Presentamos un caso en el que no fue un fármaco, sino el consumo de cocaína, lo que puso de manifiesto un patrón típico de Brugada

Brugada syndrome is characterized by the presence of right bundle branch block on electrocardiography and by ST-segment elevation in the right precordial leads (V1-V3), by the absence of structural cardiac abnormalities, and by episodes of syncope or sudden death. On occasion, diagnosis is made difficult by temporary normalization of the ECG. The condition can be unmasked by potent sodium channel blockers, such as flecainide. Our patient presented with a Brugada syndrome-type ECG after intake of a large amount of cocaine

[Arrhythmia induction during atrial pacing with atrial floating electrodes]. / Inducción de arritmias durante la estimulación auricular mediante electrodos flotantes auriculares.

Atrial pacing with floating electrodes primarily designed for single lead VDD systems has disadvantages attributable to the floatability of the electrodes. Body and breathing movements cause changes in the position of the atrial dipole that can lead to failure of atrial capture and sensing, and even alternation of the stimulated chamber. We report the induction of typical intranodal tachycardia episodes related to intermittent failure of atrial capture in a patient with an implanted single lead DDD pacing system. Such systems pose a substantial risk of potentially arrhythmogenic asynchronous pacing.

Single lead DDD pacing using electrodes with longitudinal and diagonal atrial floating dipoles.

In this study, an assessment was made of the possibilities of single lead DDD pacing in two groups: a group of 15 patients in whom a lead with a longitudinal atrial "floating" dipole was implanted, and another group of 10 patients with a lead with a diagonal atrial "floating" dipole. In both groups, the electrodes were connected to a SLD generator. At discharge, atrial capture was achieved with the unipolar mode in 17 of 25 patients, whereas in the group carrying the longitudinal atrial dipole, atrial capture was achieved with the overlapping biphasic impulses (OLBI) system in 12 of 15 patients and in all 10 patients in the group with the diagonal atrial dipole. At 3 months, atrial capture was achieved with the unipolar mode in 13 of 22 patients (5.75 +/- 1.77 V/0.5 ms), whereas with the OLBI system atrial capture was achieved in 8 of 13 patients carrying the longitudinal atrial dipole (3.11 +/- 1.13 V/0.5 ms), and in 8 of the 9 patients carrying the diagonal atrial dipole (2.80 +/- 0.69 V/0.5 ms). In this study, the use of the OLBI system led to a significant reduction of atrial threshold (P < 0.0001). Phrenic stimulation is the main untoward effect reported during single lead DDD pacing, a lower incidence being detected in the group carrying the diagonal atrial dipole (10 vs 35.7%, P = NS). Other limitations of this form of pacing could result from a crossed stimulation phenomenon detected in a patient during single lead DDD pacing.