Unusual cause of hypoxemia after automatic implantable cardioverter‑defibrillatorleads extraction.

The indication of pacemaker/AICD removal are numerous. Serious complication can occur during their removal, severe tricuspid regurgitation is one of the complication. The occurrence of PFO is not uncommon among adult population. Shunting across PFO in most circumstance is negligible, but in some necessitates closure due to hypoxemia. We report a case of 62 year old man, while undergoing AICD removal, had an emergency sternotomy for cardiac tamponade. Postoperatively, he experienced profound hypoxemia refractory to oxygen therapy. Transthoracic Echocardiogram was performed to rule out intracardiac shunts at an early stage, but it was difficult to obtain an good imaging windows poststernotomy. A small pulmonary emboli was noted on CTPA, but was not sufficient to account for the level of hypoxemia and did not resolve with anticoagulation. Transesophageal echocardiogram showed flail septal tricuspid valve with severe TR and bidirectional shunt through large PFO. Patient was posted for surgery, tricuspid valve was replaced and PFO surgically closed. Subsequently, patient recovered well ad was discharged to home. Cause of hypoxemia might be due to respiratory or cardiac dysfunction. But for hypoxemia refractory to oxygen therapy, transoesophageal echocardiogram should be always considered and performed early as an diagnostic tool in post cardiac surgical patients.

Implante de un cardiodesfibrilador bicameral vía vena cava superior izquierda persistente / Implant of a Dual-chamber Implantable Cardioverter Defibrillator through a Persistent Left Superior Vena Cava

La vena cava superior izquierda persistente (VCSIP) es la anomalía congénita venosa del tórax más frecuente. Se encuentra en el 0,3% de la población general y en el 5-10% de los pacientes con cardiopatías congénitas. Generalmente evoluciona en forma asintomática y no genera trastornos hemodinámicos, pero su reconocimiento es importante, ya que puede dificultar la introducción de catéteres para mediciones hemodinámicas, los implantes de marcapasos cardíacos (MCP) y de cardiodesfibriladores automáticos implantables (CDAI), especialmente cuando se utiliza la vía cefálica o la subclavia izquierda. En el caso clínico que se presenta se efectuó el implante de un CDAI bicameral vía VCSIP, descubierta durante el procedimiento. Asimismo, se muestran las características de esta variedad anatómica mediante tomografía cardíaca computarizada de 64 cortes (TCC64).

Persistent left superior vena cava (PLSVC) is the most common congenital defect in the thoracic venous system, with an incidence of 0.3% in the general population and of 5-10% in patients with congenital heart disease. This asymptomatic condition does not produce hemodynamic impairment; however, it should be recognized as its presence poses technical challenges in the introduction of catheters for hemodynamic measurements and for placement of pacemakers (PMs) and implantable cardioverter defibrillators (ICD) via the cephalic vein or the left suclavian vein. In the present case report we describe the implantation of a dual-chamber ICD through a PLSVC discovered during the procedure. In addition, images from cardiac 64-row multidetector computed tomography (64-row CT) show the anatomic features of this variety.

Conceptos actuales sobre la muerte súbita / Current concepts on sudden death

La muerte súbita se define como aquella que ocurre antes de una hora de la aparición de los síntomas. Es una condición grave que en diversos países supone un problema de salud pública y que en México implica entre 33 y 53 mil muertes anuales, en su mayoría ligadas a enfermedad isquémica del corazón. La causa primordial de la muerte súbita son las arritmias ventriculares graves, sin embargo determinar qué sujetos son susceptibles de tener un episodio arrítmico es complejo y por ello la relación costo efectividad de las medidas de estratificación de riesgo suele ser mala. En el presente trabajo se revisan las diferentes estrategias para determinar el riesgo de muerte súbita. Las estrategias para el tratamiento oportuno de la muerte súbita relativas a la población general utilizadas en diversos países tienen impactos variables en la supervivencia, sin embargo, en las poblaciones seleccionadas con alto riesgo de padecer un evento arrítmico ventricular, la mejor terapia disponible actualmente es el desfibrilador automático implantable, aunque en el trabajo se discuten otras opciones de tratamiento. En nuestro país es necesario hacer un importante esfuerzo de detección prevención y tratamiento oportuno para limitar las consecuencia de este problema.

Sudden death is defined as the death occurring less than one hour before the onset of the patient's symptoms. It is a severe condition considered a public health issue in several countries and in ours, it accounts for 33 000 to 53 000 annual deaths mainly related to ischemic heart disease. The main cause of sudden death are severe ventricular arrhythmias, but determining what patients are at risk for such an episode is complex, that is why risk stratification is usually a low cost-effective intervention. In the present study, we describe different sudden death risk stratification strategies. Different sudden death treatment strategies regarding general population have different success rates in different countries, nevertheless, among select high risk populations; the best therapy currently available is the automatic implantable cardioverter defibrillator. We also discuss other treatment options. In Mexico it is deemed necessary to do an important effort for the early detection, prevention and treatment of sudden death in order to limit the consequences of this problem.