Background
The aim of this study was to investigate patients with unstable angina (UA) and the predictive factors of these arrhythmias and to determine whether this complication behaves as an independent variable with regard to mortality, increased length of stay in an ICU/CCU, and the performance of percutaneous coronary intervention (PCI).
Material and Method
The retrospective cohort study included all patients diagnosed with UA and included in the Spanish "ARIAM" database between June 1996 and December 2005. Univariate and multivariate analyses were performed to evaluate the factors associated with these arrhythmias. 17,616 patients were included.
Results
Sustained ventricular tachycardia (SVT) occurred in 0.5%. The factors associated with its development were age, cardiogenic shock, and non-sustained ventricular tachycardia. SVT was associated with mortality (adjusted OR: 9.836, 95%CI: 1.81-53.33). Ventricular fibrillation (VF) occurred in 1%. In the multivariate study the variables that persistently associated independently with the development of VF were gender, Killip class, and high degree atrioventricular block (HDAVB). VF was associated with higher mortality (27.1% vs. 0.9%). Nevertheless, VF was not seen to be a variable independently associated with mortality in UA patients. Only VF was an independent variable in length of stay (adjusted OR: 2.059, 95%CI: 1.175-3.609). Neither SVT nor VF were independent variables associated with PCI.
Conclusions
Patients with UA complicated by SVT or VF represent a special high-risk subgroup with poor prognosis, which could lead to their being stratified towards a poor prognosis subgroup.

Keywords: Multivariate Analysis, Databases, Factual, Angina, Unstable - complications, Aged, 80 and over, Ventricular Fibrillation - complications