[A study on clinical and electrophysiologic characteristics of ventricular tachycardia: comparison of differences on its sustenance].

The purpose of this study was to clarify the difference of clinical and electrophysiologic characteristics between sustained ventricular tachycardia (SVT) and nonsustained ventricular tachycardia (NSVT). 40 patients consisting of 24 males and 16 females with an average age of 50.0 years (range from 19 to 83), who had shown ventricular tachycardia (VT) on electrocardiogram, were studied consecutively. The patients were divided into SVT group (19 cases) and NSVT group (21 cases). Ventricular stimulation was performed up to triple extrastimuli, and ventricular burst pacing was used when required. After VT was induced, R-R interval during VT was measured and an antiarrhythmic agent was given by bolus injection. Echocardiography was used for measurement of left ventricular ejection fraction (EF) and for evaluation of mitral valve prolapse (MVP). Palpitation and oppressive sensation were dominant in SVT (84.2%), while dizziness and syncope were prominent in NSVT (57.1%). Organic heart disease (OHD) was observed in only 42.1% of SVT, and in none of NSVT. MVP was observed in 6 patients of SVT and in 5 patients of NSVT. EF was significantly higher in NSVT (67.1%) than in SVT (56.9%) (p less than 0.02), while it was not significantly different in cases of NSVT and SVT where OHD was not present (64.4%). VT was induced and sustained in 17 out of 19 patients (89.5%) in SVT by ventricular stimulation. In NSVT, VT was induced in 6 of 21 patients (38.6%), but it was not sustained in any of them. The induction of VT in NSVT appeared to require more extrastimuli than in SVT. The R-R interval in SVT was longer than in NSVT (345.9 +/- 84.6 msec and 245.0 +/- 40.7 msec, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)