[A new system for dynamic electrocardiography. First clinical trial]. / Unovo sistema per elettrocardiografia dinamica. Prima esperienza clinica.

The development of a reliable system for analysis of ambulatory ECG recordings, for evaluation of arrhythmias and ST-T segment changes is a great challenge for technology and cardiovascular medicine. Signal superimposition or AVSEP system, conceived by Norman J. Holter, has been widely used and is employed even in recent sophisticated devices for analysis of ambulatory ECG recordings. As an alternative way we have chosen contourography, known since 1966, enhanced by a dynamic and perspective effect (Fig. 1). Figure 2 shows the display mechanism of the ECG signal. Cardiac cycles are continuously sampled, triggered and positioned along the running time axis. The QRS complexes undergo progressive amplitude decrease while "sliding" toward a viewpoint adjustable by the operator (Fig. 3). As memory contains a fixed number of cycles, the latest cycle enters the screen while the oldest falls out. Instead of being superimposed as in AVSEP system, cardiac cycles are displayed separately. In this way it is possible to make comparisons between one cycle and another or among different areas of the ECG tracing. At any instant, the tracing can be stopped, and an intensified area of interest can be recorded on a paper strip in a standard fashion (Fig. 4). A clinical comparison has been performed between this device and two different commercial systems; 25 tapes, 24 hours each, have been separately analyzed by two cardiologists with the Avionics system and 25 with the Pathfinder, and then with the new system. Each operator was not aware of the results of the other one.(ABSTRACT TRUNCATED AT 250 WORDS)