[Determining factors of the repetitive bursts in ventricular tachycardia]

24-h ECG recordings were studied in 60 patients suffering from salvos of repetitive ventricular tachycardia (VT), in order to determine the parameters affecting the repetitive response in ventricular arrhythmias. The tracings were analysed with the use of ATREC II system allowing the systematic study of 15 RR intervals and the heart rate in the 3 min preceding each type of event. The mean number of events taken into account per patient and per 24h of recording amounted to 673 +/- 521 for isolated ventricular extrasystoles, to 568 +/- 461 for paired ventricular extrasystoles and 435 +/- 810 for bursts of VT. The whole group was divided into two groups according to the absence (A) or presence (B) of associated cardiopathy. Group A included 30 patients with a mean age of 42 +/- 17 years, group B included 30 patients with a mean age of 42 +/- 17 years, group B included 30 patients with a mean age of 57.4 +/- 12 years. Three major factors responsible for the repetitive activity could be disclosed: The heart rate preceding isolated ventricular extrasystoles was lower than that preceding the salvos of VT (p less than 0.01) the duration of which increased in a linear way with the sinus rate; Duration of the cycle preceding the last sinus beat before the bursts (long duration in 77% in group A and in 57% in group B). In 60% of cases in group A and 40% in group B the coupling interval was all the more long as the response was repetitive.(ABSTRACT TRUNCATED AT 250 WORDS)