Electrocardiogram ambulatory monitoring: technological evolution and current prospectives]

The value of ambulatory ECG monitoring in the investigation of arrhythmic or ischemic events with paroxysmal patterns is well-known and its use is widespread. More recently, technical advances in informatics and in ECG signal digitizing have rapidly developed the current available ambulatory ECG instruments, reducing the time necessary for pattern analysis meanwhile assuring acceptable accuracy and reliability of the results. ECG recording techniques other than traditional Holter monitoring are now available such as transtelephonic transmission of ECG signal recorded in real time or previously stored in solid state memory by intermittent recorders that can be switched on by the patients himself at the first prodroms or at the end of the event. These "loop recorders" make it possible to indefinitely extend ECG monitoring time, reducing costs and increasing record sensitivity in comparison to conventional Holter monitoring. Moreover, recent technological development of Holter monitoring makes it possible to perform heart rate variability analysis and late potentials research in addition to traditional analysis of cardiac rate and ventricular repolarization. Thus Holter recording may become, combined with other usual risk factors, a polyparametrical non invasive approach to sudden cardiac death risk assessment characterised by low cost/benefit ratio and by large screening capacity.