title: [Determining factors of acceleration in sustained monomorphic ventricular tachycardias in response to bursts of stimuli].
abstract: To analyse the determinants of acceleration of sustained monomorphic ventricular tachycardias in response to bursts of rapid ventricular pacing, we studied 46 consecutive patients with 90 distinct ventricular tachycardias during which one or more burst of rapid pacing were delivered. Tachycardia acceleration was observed in 11 tachycardias in 8 patients. The highest incidence of acceleration was observed in patients with left ventricular dysfunction of non coronary origin. There was a non significant trend towards lower values of left ventricular ejection fraction in patients with acceleration. There were no significant differences between ventricular tachycardias with of without acceleration in respect to: clinical presentation, QRS morphology, tachycardia cycle length and treatment with antiarrhythmic drugs. The shortest cycle of bursts of rapid pacing, was lower in tachycardias with acceleration than in those without it (229 +/- 57 ms vs 283 +/- 67 ms; p = 0.006) and tachycardias with acceleration showed a lower relation between burst cycle length and tachycardia cycle length (69 +/- 9% vs 84 +/- 8%; p < 0.001). The negative predictive value of acceleration was 75% for bursts of rapid pacing with a cycle length > or = 250 ms, and 96% for values of the relation between the burst cycle length and the tachycardia cycle length > or = 70%. This parameter show a very high discriminating value with of without antiarrhythmic drugs effect. Acceleration of sustained monomorphic ventricular tachycardias in response to bursts of rapid pacing depends on, the pacing rate and the relation between pacing rate and tachycardia rate.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Servicio de Cardiología, Hospital General Gregorio Marañón, Madrid.
authors.forename: D
authors.initials: D
authors.lastname: San Román Sánchez
authors.forename: J
authors.initials: J
authors.lastname: Almendral Garrote
authors.forename: A
authors.initials: A
authors.lastname: Arenal Maíz
authors.forename: J L
authors.initials: JL
authors.lastname: Delcán Domínguez
mesh_terms: D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology / Q000627:therapeutic use; D004558:Electric Stimulation / Q000379:methods; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000503:physiopathology*
chemical_list: D000889:Anti-Arrhythmia Agents
vernacular_title: Determinantes de aceleración en las taquicardias ventriculares monomórficas sostenidas en respuesta a trenes de impulsos.