Voluntary sequential ambulatory recording is a diagnostic method of recording per-critical electrocardiographs in symptomatic patients with the aid of a portable solid-state technology recorder. In order to assess the value of this technique in the detection of arrhythmias, a multicenter study was performed in 1,287 symptomatic patients suspected of having paroxysmal arrhythmias (palpitations in 86.5% of cases). The quality of the sequential ambulatory recording was judged to be good in 54.9% and mediocre in 40.2% of cases: only 4.9% of recordings were uninterpretable. This technique allowed identification of a cardiac arrhythmia related to symptoms in 42.5% of the 1,091 cases which were analysed; sustained supraventricular tachycardia (11.7%), ventricular extrasystoles (14.9%) and simple sinus tachycardia (9.5%) were the principal abnormalities. The per-critical recording was negative in 57.5% of patients, suggesting a purely functional origin of symptoms in these cases. Atrial fibrillation was more common in hypertensive patients (11.3% vs 5.5% in normotensives, p less than 0.01) as were ventricular extrasystoles (23.1% vs 13% in normotensives, p less than 0.001). Voluntary sequential ambulatory recording seems to be a technique well adapted to the detection of symptomatic arrhythmias and a useful complement to Holter recording.