Factores predictores de aparición de fibrilación auricular en pacientes con miocardiopatía dilatada / Predicting factors of atrial fibrillation in patients with dilated cardiomyopathy

Resumen Introducción El uso de terapia anticoagulante en pacientes con miocardiopatía dilatada es controvertido. El riesgo hemorrágico hace que habitualmente no se use en pacientes en ritmo sinusal. Objetivo Analizar los factores predictores de fibrilación auricular (FA) en pacientes con miocardiopatía dilatada y fracción de eyección del ventrículo izquierdo (FEVI) < 40. Método: Se estudiaron los pacientes incluidos en el registro multicéntrico UMBRELLA a quienes se había implantado un desfibrilador (DAI) bicameral o tricameral y que presentaban miocardiopatía dilatada isquémica o no isquémica y FEVI < 40%. Se definió FA como cualquier episodio > 30 segundos de duración y una frecuencia auricular > 175 latidos por minuto. Resultados Se incluyeron 684 enfermos. La mediana de edad fue de 70 años (rango intercuartílico [RIQ]: 62-77). El 79.1% eran varones. La FEVI fue < 30% en el 76.3%. El 87.3% presentaban insuficiencia cardiaca (ICC) clínica. Se implantó un DAI resincronizador en el 59.5%. El 51.2% tenían bloqueo de rama izquierda del haz de His y el 7.1% de rama derecha (BRDHH). Se documentó FA en el 49% de los enfermos con una mediana de seguimiento de 29.93 meses (RIQ: 14.78-45.63). Las variables que se relacionaron con la aparición de FA fueron la presencia de ICC (hazard ratio [HR]: 2; intervalo de confianza del 95% [IC 95%]: 1.31-3.04; p = 0.001), el BRDHH (HR: 1.48; IC 95%: 1-2-18; p = 0.045), el ictus previo (HR: 2.11; IC 95%: 1.4-3.19; p < 0.001) y la edad > 75 años (HR: 1.21; IC 95%: 1.05-1.40; p = 0.008). Conclusiones La edad > 75 años, el BRDHH, la ICC y el ictus previo predicen la aparición de FA en la población con miocardiopatía dilatada y FEVI < 40%.

Abstract Introduction Anticoagulant treatment in patients with dilated cardiomyopathy and sinus rhythm is controversial due to haemorrhage risk. Objective To analyze the factors predicting atrial fibrillation (AF) in patients with dilated cardiomyopathy and ejection fraction (LVEF) < 40%. Method All patients included in UMBRELLA multicentre registry without AF, who had a dual or three-chamber implantable cardiac defibrillator (ICD), dilated cardiomyopathy and LVEF < 40% were included. AF was defined as any episode > 30 seconds of duration and atrial frequency > 175 bpm. Results 684 patients were included. Median age was 70 years (IQR 62-77); 79.1% were male. LVEF was < 30% in 76.3% of cases; 87.3% presented clinical heart failure (CHF). A CRT-D was implanted in 59.5%; 51.2% of patients presented Left Bundle Branch Block (LBBB) and 7.1% presented Right Bundle Branch Block (RBBB). AF was documented in 49% of patients, with a median follow-up of 29.93 months (IQR: 14.78-45.63). The presence of CHF (HR: 2; 95% CI: 1.31-3.04; p = 0.001), RBBB (HR: 1.48; 95% CI: 1-2-18; p = 0.045), previous stroke (HR: 2.11; 95% CI: 1.4-3.19; p < 0.001) and age > 75 years (HR: 1.21; 95% CI: 1.05-1.40; p = 0.008) were associated with diagnosis of AF. Conclusions Age > 75 years, RBBB, CHF and previous stroke are predictors of AF development in the population with dilated cardiomyopathy and LVEF < 40%.

The clinical impact of untreated slow ventricular tachycardia in patients carrying implantable cardiac defibrillators.

INTRODUCTION: The clinical impact of slow ventricular tachycardia (VT), occurring in patients carrying implantable cardiac defibrillators (ICD), is still under debate. METHODS AND RESULTS: From the UMBRELLA registry (multicenter, observational, and prospective study on patients with ICD), 659 episodes of slow VT were observed in 97 patients. Untreated slow VT (n = 93) had longer duration (23.7 min, CI95%: 10-39), compared with episodes treated effectively by anti-tachycardia pacing (ATP; n = 527; 0.32 min, IC95%: 0.22-0, 48) or shock (n = 39; 1 min, CI95%: 0.8-1.2). Despite of longer duration, the time to the first contact with the medical services was similar to those episodes treated by ATP (50 days [CI95%: 45-55] vs. 41 days [CI95%: 39-44]). However, both were significantly longer than the time observed in episodes treated with shock (10 days, CI95%: 6-15). This tendency was maintained with successive interrogations of the device (2nd and 3rd). There were no significant differences in mortality during follow-up (48 ± 16 months), neither other adverse outcomes, between patients who presented untreated slow TV and those who did not (log-rank p = 0.28). In a Cox regression analysis, the variable "presenting untreated episodes of slow VT" was not able to predict mortality. However, being in sinus rhythm (vs. atrial fibrillation, OR: 0.31, p = 0.009), narrower QRS (OR: 1.036, p = 0.037) and diabetes (OR 4.673, p = 0.049) appropriately predict survival. CONCLUSIONS: Untreated slow VT does not significantly worsen patient prognosis. Our results support the limitation of therapies to ATP only, thus avoiding therapies that have been associated with increased risk of morbidity and mortality.