Arritmias y riesgo de muerte súbita en Cardiomiopatía Hipertrófica

The risk of sudden death in hypertrophic cardiomyopathy is related to the presence of ventricular arrhythmias in most cases. Finding the best schemes to assess the probability of arrhythmic complications will remain a challenge for modern Cardiology. Meanwhile, the multifactorial approach is the best strategy to avoid the unnecessary implantation of devices such as the implantable cardioverter defibrillator. Although the electrocardiogram remains an excellent diagnostic tool, even before echocardiographic expression, it does not have a clear role as a risk factor. However, the identification of associated arrhythmias such as preexcitation or long QT and variants of presentation as apical hypertrophic cardiomyopathy, allows identifying patients with high probability of sudden death. During the last few years, cardiac resonance and quantification of intramyocardial fibrosis (the basic mechanism of ventricular arrhythmias) have gained an important role in the evaluation of these patients. In particular, pediatric patients must have an individualized approach due to the poor prognosis at early ages and the uncertain role of different tools for risk assessment and treatment.El riesgo de muerte súbita en la cardiomiopatía hipertrófica está relacionado a la presencia de arritmias ventriculares en la gran mayoría de los casos. Es y será un reto para la Cardiología moderna encontrar los mejores esquemas para valorar la probabilidad de complicaciones arrítmicas, siendo por ahora el enfoque multifactorial la mejor estrategia para evitar el implante innecesario de dispositivos como los cardiodesfibriladores. Si bien, el electrocardiograma (ECG) sigue siendo una excelente herramienta para el diagnóstico, incluso en fases sin expresión ecocardiográfica, no tiene un rol claro en la estratificación de riesgo. Sin embargo, la asociación de cambios en el ECG y otros hallazgos como la presencia de preexcitación y/o QT largo, así como variantes de presentación tipo cardiomiopatía hipertrófica apical, permitirían identificar a pacientes con alta probabilidad de muerte súbita. Desde hace unos años la resonancia cardíaca y la cuantificación de la fibrosis intramiocárdica (mecanismo básico de las arritmias ventriculares) tienen un rol cada vez más importante en la evaluación de estos pacientes. En especial, la población pediátrica debe tener una visión individualizada por el mal pronóstico a edades tempranas y por el rol incierto de diferentes herramientas para la valoración del riesgo y tratamient

Phenotypic Assessment of Endothelial Microparticles in Patients with Heart Failure and After Heart Transplantation: Switch From Cell Activation to Apoptosis

Endothelial microparticles (EMPs) are sub-microscopic membrane vesicles that are shed from the surface of endothelial cells during activation, injury and/or apoptosis. Endothelial cells release phenotypically and quantitatively distinct endothelial microparticles (EMPs) in activation and apoptosis. Therefore, the phenotypic assessment of EMPs can provide useful information reflecting the nature of endothelial injury. We tested the hypothesis that heart transplantation (HT) modifies the pattern of endothelial injury seen in patients with congestive heart failure (CHF). Flow cytometry was used to measure EMPs identified by E-selectin (CD62) and platelet–endothelial cell adhesion molecule 1 (CD31) in 23 patients with advanced heart failure and in 23 HT recipients. A cohort of 23 healthy individuals served as controls. Heart failure patients were found to have significantly higher levels of EMP62E (577 counts/μl) than controls (192 counts/μl) and post-transplant patients (152 counts/μl) ( p < 0.0001). Levels of endothelial microparticles expressing CD31 were significantly different among study groups (analysis of variance [ANOVA], p = 0.001). Heart failure patients had significantly higher levels (1,526 counts/μl) than controls (395 counts/μl) ( p < 0.01). Levels of EMP31 remained elevated after heart transplant (935 counts/μl) ( p = non-significant). The EMP62/EMP31 ratio, an index of activation (high ratio) or apoptosis (low ratio), was significantly different between the groups (ANOVA, p = 0.01). Post-transplant patients had significantly lower ratios (0.16) than CHF patients (0.38) and controls (0.49). Cardiac transplantation is associated with a different pattern of endothelial cell injury than that seen in heart failure. The phenotypic assessment of EMPs in post-transplant patients is consistent with increased apoptotic activity