Ambulatory Holter electrocardiography: choice of technologies and clinical uses.

Rapid growth in the use and complexity of Holter monitoring technologies has resulted in the diverse recorders and analysis devices that are compared in this review. Holter recording modes include continuous recording, which makes all electrocardiographic (ECG) data available for analysis; patient-activated recording, which is useful for capturing infrequent symptomatic arrhythmias; and event recording, which provides data on ECG events detected by the recorder, but whose reliability is limited. Various sophisticated, computer-based analysis systems exist, with varying prices and degrees of accuracy and reliability. Quantitative data are essential in the use of Holter monitoring to define the response of ventricular arrhythmias to therapeutic interventions, but the physician must be wary of quantitative data unless a quality-control program has been established and validated. Although Holter monitoring is safe, problems in recording and in differentiating artifacts from true cardiac rhythm disturbances may result in false clinical diagnoses unless these problems are recognized.