RESUMEN
OBJECTIVE: Describe the frequency of high degree atrioventricular block (HDAVB) in patients with unstable angina (UA), analyze the variables associated with their appearance and evaluate whether HDAVB is independently associated with increased mortality or increased length of ICU stay. DESIGN: Retrospective descriptive study of patients with UA included in the ARIAM registry. SETTING: ICUs from 129 hospitals in Spain. PATIENTS: From June 1996 to December 2003 a total of 14,096 patients were included in the ARIAM registry with a diagnosis of UA. MAIN VARIABLES OF INTEREST: Variables associated with the development of HDAVB, variables associated with the mortality of patients with UA, variables associated with the length of ICU stay of patients with UA. RESULTS: HDAVB frequency was 1%. Development of HDAVB was independently associated with the Killip classification and the presence of sustained ventricular tachycardia or ventricular fibrillation. Crude mortality of patients was significantly increased when HDAVB was present (9% versus 1%, p < 0,001). When adjusted for other variables, HDAVB was not associated with increased mortality. Development of HDAVB in patients with UA was independently associated with an increase in the length of ICU stay (adjusted odds ratio 1.89: 95% confidence interval: 1.33-5.69). CONCLUSIONS: Patients with UA complicated with HDAVB represent a high-risk population with an increased ICU stay.