Arrhythmias in ambulatory persons. A review and experience of 1,000 consecutive recordings.

The value of 24-hour ambulatory monitoring of the ECG for the diagnosis of symptoms of dizziness, palpitations and syncope is controversial. In this study results from a hospital-based, clinical service have been analysed. Of 1,000 consecutive dynamic electrocardiograms (DCG), 678 were performed for assessment of dizziness, syncope or palpitations in 405 patients. 36 of the patients had pacemakers. 60 DCGs were technically inadequate. The recordings were classified according to the correspondence between DCG findings and symptoms noted in the patient diary: (I) Completely diagnostic: significant arrhythmias (SA) corresponding to diary symptoms - 99 recordings. (II) Incompletely diagnostic: (a) absence of SA in the presence of diary symptoms - 90 recordings; (b) presence of SA but no diary symptoms - 197 recordings; (c) presence of SA corresponding to symptoms other than that for which the DCG was indicated - 52 recordings. (III) Non-diagnostic: absence of both SA and diary symptoms - 180 recordings. Incompletely diagnostic categories were regarded as clinically valuable in that they either excluded a cardiac arrhythmia as a cause of symptoms (group IIa) or they revealed SA which did not correspond to diary symptoms (group IIc). The absence of symptoms corresponding to SA was ascribed to poor diary keeping in 54 of 197 recordings. These results are discussed in the context of the findings in normal and symptomatic patients. A clinical 24-hour ambulatory ECG monitoring service provided useful diagnostic information in 65% of recordings and 74% of patients.