Today’s clinical cardiac catheterization laboratory evolved from facilities that were originally human hemodynamic research laboratories. In the 1940s and 1950s, these facilities worked out much of our current understanding of human cardiovascular physiology and pathophysiology with a principal focus on cardiac valve disease.
Catheterization laboratory physiologic recorders were developed to meet 2 needs of these endeavors:
The need to monitor a patient’s condition during invasive procedures
The need to make permanent analog recordings of physiologic signals from patients
The catheterization laboratory physiologic recorder evolved from multichannel oscillographic physiologic recorders that had been developed for animal physiologic research in the first half of the 20th century. The original physiologic recorders were ink-writing multichannel oscillographs.
The importance of displaying and recording multiple superimposed channels of physiologic signals was rapidly recognized. Thus, the first major development was the move from ink-writing oscillographs to multichannel oscilloscopic recorders. These instruments could display multiple channels of physiologic signals in real time on an oscilloscopic screen. The physician operator could view the screen in order to monitor in real time both the data being obtained and the patient’s condition. These instruments also added an important adjunct—the ability to superimpose multiple analog signals in a time-based display. This capability enhanced signal interpretation by displaying the nuances of relationships between different signals. (eg, superimposing pressure signals from adjacent cardiac chambers facilitates the recognition and measurement of pressure gradients.) This capability required incorporating photo-optical recorders that could record the individual superimposed oscilloscopic beams on light-sensitive paper, enabling permanent recordings of the physiologic signals.
These early instruments made the development of cardiac catheterization possible. However, they also had many shortcomings. They did not have the ability to record the events of a procedure in their entirety. The photo-optical recordings were fragile and easily degraded. It was difficult to make recordings available for remote review or to make illustrations for teaching and publication.
During the past 25 years, progress in electronic instrumentation, computer capability, and networking and improvements in display technology have fostered an evolution of the cardiac catheterization laboratory recorder, refining its functionality and enabling it to incorporate additional information management and reporting capabilities.
Currently available catheterization lab recorders are the core component of a comprehensive information system that, through hospital information system networking, has become an integral part of an overall cardiovascular information system and a health care institution’s electronic medical record.
In addition to serving their original function, current systems also serve as front ends for patient flow management, clinical database management, hospital information system data, clinical report generation, laboratory inventory management, and quality assurance analysis. Although these functionalities provide enhanced capabilities, they also require more detailed planning when selecting and configuring a system in order to optimize configurations and connectivities.
The purpose of the original catheterization laboratory recorders was to receive, condition, and display various types of patient physiologic signals that were of value for monitoring the patient and for assessing the patient’s pathophysiology. In addition to displaying signals in real time, they also had the capability to record signals for subsequent analysis.
Cardiovascular physiologic signals fall into 3 basic types:
Pressure signals from pressure transducers
Electrocardiogram (ECG) signals
Direct current (DC) voltage signals representing either voltages recorded from the patient or signals from other instruments such as flow meters, respiration and pulse oximetry probes, and other instruments
The early recorders had the capability to display these processed signals with appropriate gain in a variety of superimposition formats in order to present a comprehensive picture of the patient’s condition and the relationships between the phenomena represented by the different signals. In addition, the early recorders could produce a hard copy output to preserve selected signal recordings for archiving and analysis.
