[Value of long-term ECG in patients with syncope].

In a prospective study 24 hour long-term ECG (LT-ECG) recordings under ambulatory conditions were performed in 126 patients with syncopes (SY) of unknown origin. LT-ECG revealed arrhythmias (AR) in 57%, whereas 43% had inconspicuous findings. One patient developed a SY during LT-ECG without any evidence for arrhythmias. In 40% of these patients AR not detected previously by other methods were discovered. In 36% AR detected by LT-ECG had to be considered as precursors of syncopes (i.e. bradycardia less than 40 b.p.m., tachycardia greater than 160 b.p.m., AV-block II/II and III, or ventricular arrhythmias Lown IV). LT-ECG increased the information about the cause of syncope in 35%, whereas in 65% LT-ECG did not produce any further information. Consequently LT-ECG led in 56% to drug therapy, in 8% to PM-implantation. During a mean follow-up of 22 months 22% of patients developed again a syncopal attack and 4% died suddenly. Despite LT-ECG recording an ECG-registration during a typical syncopal attack for the confirmation or exclusion of an arrhythmogenic genesis of the SY is achieved only by chance. Nevertheless further informations with regard to precursing AR can be obtained, which may lead to therapeutic consequences in some patients. Therefore, LT-ECG has to be recommended as an essential, non-invasive procedure in patients with SY of unknown origin.