The incidence of pulmonary embolism in unexplained sudden cardiac arrest with pulseless electrical activity

PURPOSE: The cause of many cases of sudden cardiac arrest from pulseless el ectrical activity is unknown. We hypothesized that pulmonary embolism was r esponsible for a substantial proportion of these cases and used transesopha geal echocardiography to identify pulmonary embolism among patients with su dden cardiac arrest. SUBJECTS AND METHODS: We performed a prospective study at a tertiary care, university-operated county hospital, with a level 1 trauma center. Consecut ive patients (n = 36) who were admitted with (n = 20) or unexpectedly devel oped (n = 16) sudden cardiac arrest of unknown cause were studied with tran sesophageal echocardiography during cardiopulmonary resuscitation. We deter mined the presence of central pulmonary embolism, right ventricular enlarge ment, and other causes of sudden cardiac arrest (such as myocardial infarct ion and aortic dissection) using prospectively defined criteria. RESULTS: Of the 25 patients with pulseless electrical activity as the initi al event, 9 (36%) had pulmonary emboli (8 seen with transesophageal echocar diography and 1 diagnosed at autopsy) compared with none of the 1 1 patient s with other rhythms, such as asystole or ventricular tachycardia or fibril lation (P = 0.02). Of the 8 patients who had pulmonary embolism diagnosed b y transesophageal echocardiography, 2 survived to hospital discharge. CONCLUSIONS: Mortality from massive pulmonary embolism is high, particularl y if patients present with sudden cardiac arrest. Earlier diagnosis of pulm onary embolus may permit wider use of thrombolytic agents or other interven tions and may potentially increase survival. (C) 2000 by Excerpta Medica, I nc.