A historical review of echocardiographic detection of pericardial effusion.

The 26 year history of echocardiographic detection of pericardial effusion ideally demonstrates the scientific method. The initial observations by Elder and Hertz in 1954 lead to animal experiments by Feigenbaum an Soulen many years later. Human applications were confirmed again and again with cardiac catheterization, surgery, autopsy and radiologic procedures. Older methods of effusion detection were compared to this new and noninvasive method and found lacking. Echocardiography has been a safe, reliable and accurate method to establish the presence of pericardial effusion in the symtomatic and asymtomatic patient. It has been used as the diagnostic standard for other detection methods. Investigators and clinicians are now utilizing echocardiography to explain cardiac physiology when pericardial effusion is present; and to follow the effects of their therapeutic interventions. While the presence of pericardial effusion has proven to be more prevalent than expected, the pathologic and hemodynamic significance of unsuspected effusion had not yet been established. Experimental and clinical studies are continuing with the aid of computerized technology for data retrieval and analysis. Thousands of patients are examined yearly with echocardiography and their statistics roll from the pages of scientific and clinical publications. The world's literature is at one's fingertips. But--the echocardiogram and its derived data are only as good as the knowledge and skill of the examiner, technologist and physician alike who " ... must understand the physics of ultrasound, the operation of a complex electronic instrument, the nature of intracardiac anatomy, and clinical cardiology as well as echographic manifestations of normal and disease conditions. Information can seldom be extracted retrospectively from the echocardiogram that was not deliberately depicted at the time of examination." More than a quarter of a century has honed present day skills to record and interpret echocardiographic tracings of pericardial effusion. Yet, it is sobering to consider how primitive our best efforts are compared to methods still unknown which will be used by technologists and physicians fifty years from now.