title: Relation of mode of induction and cycle length of ventricular tachycardia: analysis of 104 patients.
abstract: One hundred four consecutive patients with ventricular tachycardia (VT) were examined to correlate the cycle length with the mode of initiation of VT (single, double, and triple extrastimuli and rapid pacing). Tachycardias induced with a single extrastimulus were slower (342 +/- 72 ms, mean cycle length) than those induced with double (295 +/- 60 ms) or triple (282 +/- 56 ms) extrastimuli or rapid pacing (293 +/- 40 ms). There were no differences among the last 3 groups. In 38 patients who had endocardial catheter mapping to determine the site of origin of VT, distance from stimulation site to the site of origin was estimated and correlated with mode of initiation. There was no difference in mode of initiation when the stimulation site was close (less than 3 cm), intermediate (3 to 5 cm), or distant (greater than 8 cm) from the site of origin. To address the issue of distance from stimulation site to the site of origin somewhat differently, mode of initiation was correlated with site of previous myocardial infarction in 69 patients with VT initiated from the right ventricular apex. Again, mode of initiation did not differ among patients with septal, inferior, lateral, or multiple myocardial infarctions. Thus, cycle length of VT initiated with a single extrastimulus was slower than that initiated with double or triple extrastimuli or rapid pacing and the mode of initiation of VT was unrelated to site of myocardial infarction or distance between stimulation site and site of origin of VT.
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000503:physiopathology; D006331:Heart Diseases / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology; D013610:Tachycardia / Q000473:pathology / Q000503:physiopathology*