Clinical significance of 12 lead ECG changes in patients undergoing pericardiocentesis for cardiac tamponade

Abstract

Introduction The electrocardiogram (ECG) is one of the initial tests done in patients suspected of having a cardiac Tamponade. Historically the emphasis has been on low QRS voltage and electrical alternans, which lacks specificity and sensitivity respectively. Majority of these studies included patients with pericardial effusions without tamponade. Moreover, the influence of different therapeutic interventions such as pericardiocentesis on ECG variables has not been elucidated. Objective To determine the clinical significance of 12 lead ECG changes in patients undergoing pericardiocentesis for cardiac tamponade. Methods 144 patients underwent Echo guided pericardiocentesis for cardiac tamponade at a tertiary care hospital over a period of 7 years. We compared 19 EKG variables pre and post procedure. Results Low voltage was detected in only 31 patients (29%) with 19 (18%) patients having persistent low voltage (p value = 0.0047) after the pericardiocentesis. Electrical alternans was only observed in 25 patients (23%), and persisted in 10 patients (10%) following pericardiocentesis. None of the other EKG variables measured changed reliably post procedure. Conclusion We found that although electrical alternans and low voltage were associated with cardiac tamponade, none of the ECG variables were highly sensitive or specific for the diagnosis, reproducibly changed after drainage or predicted recurrent effusion post-pericardiocentesis.