Advances in modern electrocardiographic equipment for long-term ambulatory monitoring

Electrocardiographic ambulatory "Holter" monitoring (AECG) is an essential tool in the diagnostic evaluation of patients with cardiac arrhythmias. Recent advances in digital Holter technology have improved the quality of the ECG signals and new dedicated algorithms have expanded the clinical application of software-based AECG analysis systems. Due to the availability of inexpensive large storage capacities, very long-term (weeks to months) continuous high-quality AECG monitoring will soon be available, together with devices for long-term long-distance telemetric surveillance for high-risk cardiac patients, utilizing trans-telephonic transmission of ECG data. New digital recorders will also have the capability for multichannel simultaneous recordings (currently from 3 to 8 simultaneous leads). Multichannel digital recordings will allow the recording of different biological signals by appropriate sensors, such as respiratory frequency, peripheral oxygen tension, arterial pulse pressure, EEG, and others. This will transform conventional AECG in ambulatory policardiography, allowing the comprehensive evaluation of patients with complex disorders, such as heart failure or sleep apnea syndromes. By this global approach, Holter analysis becomes a real "noninvasive electrophysiological test," to identify potential risk factors for life-threatening cardiac arrhythmias.