[Correlation between late surface potentials and inducible ventricular arrhythmias. Apropos of 115 cases]

Programmed ventricular stimulation and a search for late surface potentials (LP) by means of signal-averaging and quantification by Simson's method were performed in 115 patients divided into five groups: group I (n = 50) with no myocardial infarction (MI) and no clinical or induced ventricular tachycardia (VT); group II (n = 28) with MI and no clinical or induced VT; group III (n = 8) with MI, no clinical VT but induced non sustained VT (NSVT); group IV (n = 19) with MI, no clinical VT but induced sustained VT (SVT); group V (n = 15) with clinical and induced VT. The terminal portion of the averaged signal (AS) was analyzed by three parameters: duration of AS terminal portion less than 40 microvolts (Dur TP), AS amplitude 50 and 40 ms before its end (Amp 50, Amp 40). The presence of TP was defined in two ways: criterion A = Amp 40 less than 25 mcv, criterion B = at least two sub-criteria: Dur TP greater than 40 ms, Amp 50 less than 25 mcv, Amp 40 less than 15 mcv. Compared to groups I and II, the AS of group V was characterized by a prolonged and low amplitude terminal portion (p less than 0.001). Groups III and IV were intermediate. The incidence of TP in groups I to V was 20, 28, 37, 56 and 80% respectively with criterion A, and 4, 4, 0, 28 and 66% respectively with criterion B. The lower incidence of TP in group IV as compared to group V was probably due to the induction of purely artefactual SVT's, notably those with rapid cycle (greater than 270 cps/min) which are remarkable on several accounts.(ABSTRACT TRUNCATED AT 250 WORDS)