Objectives: The study evaluates the prognostic impact of anemia in patients presenting with ventricular tachyarrhythmias and aborted cardiac arrest.

Methods: The present longitudinal observational registry-based monocentric cohort study included retrospectively all consecutive patients presenting with ventricular tachyarrhythmias on admission from 2002 to 2016. Anemic patients (haemoglobin distribution < 12 g/dl) were compared to non-anemic patients (haemoglobin distribution ≥ 12 g/dl). The primary endpoint was long-term all-cause mortality at 2.5 years. Secondary endpoints were cardiac death at 24h, all-cause mortality at index hospitalization and after discharge, and the composite arrhythmic endpoint of cardiac death at 24 hours, recurrent ventricular tachyarrhythmias, and appropriate ICD therapies. 

Results: A total of 2.184 consecutive patients were included of which 30% were anemic and 70% non-anemic.Most anemic patients suffered from hemorrhagic anemia (29%) followed by hypoproliverative anemia (27%). A fifth of patients suffered from unexplained anemia that was sent for ambulatory workup, whereas a tenth of patients was affected by a cardiac death ≤ 24 h documented anemia. Another tenth of patients suffered from hemolytic anemia. The smallest group included patients with idiopathic anemia (5%). Anemia was associated with the primary endpoint of long-term all-cause mortality at 2.5 years (65% vs. 29%, log-rank p=0.001; HR=2.441; 95% CI 2.086-2.856; p=0.001) and with the secondary endpoints of cardiac death at 24h, all-cause mortality at index hospitalization and after discharge. Furthermore, anemia was associated with the composite arrhythmic endpoint. Even after multivariable adjustment increased long-term mortality was associated with anemia (HR=1.773), besides chronic kidney disease (CKD, HR=2.631), LVEF < 35% (HR=2.106), cardiogenic shock (HR=1.784), cardiopulmonary resuscitation (CPR, HR=1.564), male gender (HR=1.433), diabetes mellitus (HR=1.073) and increased age (HR=1.024). An acute myocardial infarction (AMI, STEMI: HR=0.519, NSTEMI: HR=0.775) and the presence of an ICD (HR=0.265) was beneficial. Anemia was not associated with the composite arrhythmic endpoint after multivariable adjustment.                                                                                                                         
       
Conclusion: Anemic patients are associated with impaired long-term prognosis at 2.5 years, cardiac death at 24h, all-cause mortality at index, and with the composite arrhythmic endpoint when presenting with ventricular tachyarrhythmias and aborted cardiac arrest. Increased long-term mortality was still evident after multivariable adjustment.