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Background: Intravascular ultrasound imaging provides information on vascular lumen and arterial wall structure and it has potential application in arterial wall dynamic study. The aim of this study was to develop a computer assisted system for analysing digitised cross sectional ultrasound images of coronaries to easily display and quantify coronary dynamic and its relationship with arterial wall morphology., Methods and Results: To extract the anatomical regions of interest from the digitised sonograms, automatic image segmentation and interactive procedures for manual correction were implemented. This step included the recognition of the lumen edge and an analysis of gray level intensity of the wall. Subsequently, a virtual 3D reconstruction of lumen and vessel wall was done in a Cartesian system where the XY plane was parallel to each cross-sectional sonogram, while the Z axis corresponded to the acquisition time. The baricentre of vascular lumen was used as a reference for alignment. We obtained a cylinder-like solid representing the behavior of the arterial cross-sectional sonogram in time, with the possibility to look either at the wall or at the lumen. In this virtual solid it was possible to measure the variation of lumen area and of 16 hemidiameters; in addition, the derivatives of these values, allowing an estimate of the velocity of events, can be obtained., Conclusions: The described computerised system for the analysis of intravascular ultrasound images could become a very useful tool for 3D representation and quantitative monitoring of coronary compliance and their relationship with segmental arterial wall morphology.

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)

The role of 24 hour Holter monitoring in the screening of patients complaining of palpitations is reviewed. The term "palpitations", although not always unequivocally used, implies the presence of an arrhythmia. The clinical-instrumental correlation of an intermittent symptom is made possible by continuous electrocardiographic monitoring. Answers to be expected from a 24 hour Holter monitoring in order to achieve an early characterization of the arrhythmia are related to: site of origin, incidence, circadian distribution, prognostic stratification, events aggregation, presence of other asymptomatic abnormalities (rhythm, ST-T).