Holter monitoring (HM) of the electrocardiogram (ECG) is used currently for the management of patients with ventricular preexcitation (PE). It makes it possible to detect inconstant PE which is considered a marker of a favourable clinical development. HM of ECG is not suitable for the detection of paroxysmal supraventricular tachycardias (PSVT) in patients with PE, as their presence is detected only exceptionally during HM. It can be used for the detection of other disorders of the cardiac rhythm than PSVT, in particular in supraventricular and ventricular extrasystoles (SVES and VES). Frequent SVES and VES detected during HM can as potential triggers of PSVT indicate a higher risk of these arrhythmias. HM is used for the objectivization of relatively frequent, sometimes quite polymorphous subjective complaints of patients with PE. Subjective data of these patients are very unreliable and from these data it is not possible to draw conclusions on the presence or absence of disorders of the cardiac rhythm. HM of ECG is not a suitable method for the evaluation of the effectiveness of medicamentous antiarrhythmic treatment of PSVT because of their considerable spontaneous variability. It may be, however, used partly for the evaluation of success of radiofrequency ablation treatment. Evaluation of long-term ambulatory ECG Holter tracings in patients with PE is more complicated and more time consuming than in subjects without PE. In any case it is essential that the record should be evaluated by an experienced physician with sufficient knowledge in arrhythmology.

Keywords: Electrocardiography; Electrocardiography, Ambulatory; Humans; Pre-Excitation Syndromes /diagnosis/