Abstract
Objectives—To examine the effect of isoprenaline on slow and fast pathway properties and tachycardia initiation. Design—Consecutive patients, prospective study. Setting—Referral centre for cardiology, academic hospital. Patients—24 patients suffering from common type atrioventricular nodal re-entrant tachycardia (AVNRT). Interventions—Programmed electrical stimulation and radiofrequency catheter ablation of the slow pathway. Measurements and main results—AVNRT was induced before and after the administration of isoprenaline in nine patients (group 1), before isoprenaline only in five (group 2), and after isoprenaline only in 10 (group 3). The anterograde effective refractory period of the fast pathway was prolonged significantly during isoprenaline administration in group 1 (405 (31) v 335 (34) ms, p < 0.001) and shortened in group 2 (308 (57) v 324 (52) ms, p = 0.005). There was also significant shortening in group 3 (346 (85) v 395 (76) ms, p < 0.001). Isoprenaline administration did not result in a significant change of the anterograde effective refractory period of the slow pathway in groups 1 and 3, but eliminated slow pathway conduction in group 2. Isoprenaline significantly shortened the minimal and maximal atrial to His bundle conduction interval recording in response to each extrastimulus of the slow pathway (210 (24) v 267 (25) ms, p < 0.001 and 275 (25) v 328 (25) ms, p < 0.001, respectively) in group 1 and significantly prolonged these intervals (331 (34) v 274 (34) ms and 407 (33) v 351 (33) ms, respectively) in group 3. In all groups only minimal changes in the refractory period of the atrium occurred after isoprenaline administration. The effect of isoprenaline was also measured on the ventricular effective refractory period and on the minimal and maximal length of the ventriculoatrial (V2-A2) interval during ventricular pacing. Isoprenaline did not result in a significant change of the ventricular effective refractory period in groups 1 and 2 nor of the shortest and longest V2-A2 interval. In group 3, however, the ventricular effective refractory period and the shortest and longest V2-A2 interval shortened significantly after isoprenaline administration. Conclusions—In group 1 isoprenaline did not affect inducibility of AVNRT because it prolonged the fast pathway refractory period without affecting slow pathway conduction. In group 2 isoprenaline shortened the fast pathway refractory period and appeared to abolish slow pathway conduction. Consequencely, isoprenaline prevented induction of AVNRT. In group 3 isoprenaline facilitated induction of AVNRT. This effect seemed primarily to be the result of shortening of retrograde refractoriness of the fast pathway with prolongation of slow pathway anterograde conduction and refractory period. Keywords: atrioventricular re-entrant tachycardia; isoprenaline
Full Text
The Full Text of this article is available as a PDF (108.1 KB).
Figure 1 .
(A) Effect of intravenous isoprenaline on anterograde atrioventricular (AV) nodal conduction in a patient of group 1. The effective refractory period of the fast pathway was prolonged and conduction time of the slow pathway shortened after drug administration. (B) Effect of isoprenaline on anterograde AV nodal conduction in a patient of group 2. Slow pathway conduction was eliminated after drug administration. (C) Effect of isoprenaline on anterograde conduction in a patient of group 3. The effective refractory period of the fast pathway was shortened and conduction time over the slow pathway prolonged after drug administration. (D) Effect of isoprenaline on retrograde conduction. The ventricular effective refractory period and the retrograde conduction time were shortened after drug administration. Measurements of anterograde and retrograde AV nodal conduction were obtained using a basic cycle length of 500 ms. A2-H2, atrio-His bundle conduction interval in the His bundle recording in response to each extrastimulus; A1-A2, atrial extrastimulus; V2-A2, ventriculoatrial conduction interval; V1-V2, coupling interval of the ventricular extrastimulus.
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Akhtar M., Damato A. N., Batsford W. P., Caracta A. R., Ruskin J. N., Weisfogel G. M., Lau S. H. Induction of atrioventricular nodal reentrant tachycardia after atropine. Report of five cases. Am J Cardiol. 1975 Sep;36(3):286–291. doi: 10.1016/0002-9149(75)90477-4. [DOI] [PubMed] [Google Scholar]
- Arnold J. M., McDevitt D. G. Reflex vagal withdrawal and the hemodynamic response to intravenous isoproterenol in the presence of beta-antagonists. Clin Pharmacol Ther. 1986 Aug;40(2):199–208. doi: 10.1038/clpt.1986.164. [DOI] [PubMed] [Google Scholar]
- Arnold J. M., McDevitt D. G. Vagal activity is increased during intravenous isoprenaline infusion in man. Br J Clin Pharmacol. 1984 Sep;18(3):311–316. doi: 10.1111/j.1365-2125.1984.tb02469.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bauernfeind R. A., Wyndham C. R., Dhingra R. C., Swiryn S. P., Palileo E., Strasberg B., Rosen K. M. Serial electrophysiologic testing of multiple drugs in patients with atrioventricular nodal reentrant paroxysmal tachycardia. Circulation. 1980 Dec;62(6):1341–1349. doi: 10.1161/01.cir.62.6.1341. [DOI] [PubMed] [Google Scholar]
- DiMarco J. P., Sellers T. D., Berne R. M., West G. A., Belardinelli L. Adenosine: electrophysiologic effects and therapeutic use for terminating paroxysmal supraventricular tachycardia. Circulation. 1983 Dec;68(6):1254–1263. doi: 10.1161/01.cir.68.6.1254. [DOI] [PubMed] [Google Scholar]
- Goldreyer B. N., Damato A. N. The essential role of atrioventricular conduction delay in the initiation of paroxysmal supraventricular tachycardia. Circulation. 1971 May;43(5):679–687. doi: 10.1161/01.cir.43.5.679. [DOI] [PubMed] [Google Scholar]
- Hariman R. J., Gomes J. A., El-Sherif N. Catecholamine-dependent atrioventricular nodal reentrant tachycardia. Circulation. 1983 Mar;67(3):681–686. doi: 10.1161/01.cir.67.3.681. [DOI] [PubMed] [Google Scholar]
- Moe G. K., Mendez C. The physiologic basis of reciprocal rhythm. Prog Cardiovasc Dis. 1966 Mar;8(5):461–482. doi: 10.1016/s0033-0620(66)80032-4. [DOI] [PubMed] [Google Scholar]
- Neuss H., Schlepper M., Spies H. F. Effects of heart rate and atropine on 'dual AV conduction'. Br Heart J. 1975 Dec;37(12):1216–1227. doi: 10.1136/hrt.37.12.1216. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ross D. L., Farre J., Bar F. W., Vanagt E. J., Dassen W. R., Wiener I., Wellens H. J. Comprehensive clinical electrophysiologic studies in the investigation of documented or suspected tachycardias. Time, staff, problems and costs. Circulation. 1980 May;61(5):1010–1016. doi: 10.1161/01.cir.61.5.1010. [DOI] [PubMed] [Google Scholar]
- Sung R. J., Waxman H. L., Saksena S., Juma Z. Sequence of retrograde atrial activation in patients with dual atrioventricular nodal pathways. Circulation. 1981 Nov;64(5):1059–1067. doi: 10.1161/01.cir.64.5.1059. [DOI] [PubMed] [Google Scholar]
- Wellens H. J., Düren D. R., Liem D. L., Lie K. I. Effect of digitalis in patients with paroxysmal atrioventricular nodal tachycardia. Circulation. 1975 Nov;52(5):779–788. doi: 10.1161/01.cir.52.5.779. [DOI] [PubMed] [Google Scholar]
- Wellens H. J., Tan S. L., Bär F. W., Düren D. R., Lie K. I., Dohmen H. M. Effect of verapamil studied by programmed electrical stimulation of the heart in patients with paroxysmal re-entrant supraventricular tachycardia. Br Heart J. 1977 Oct;39(10):1058–1066. doi: 10.1136/hrt.39.10.1058. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wu D., Denes P., Bauernfeind R., Dhingra R. C., Wyndham C., Rosen K. M. Effects of atropine on induction and maintenance of atrioventricular nodal reentrant tachycardia. Circulation. 1979 Apr;59(4):779–788. doi: 10.1161/01.cir.59.4.779. [DOI] [PubMed] [Google Scholar]
- Wu D., Denes P., Bauernfeind R., Kehoe R., Amat-y-Leon F., Rosen K. M. Effects of procainamide on atrioventricular nodal re-entrant paroxysmal tachycardia. Circulation. 1978 Jun;57(6):1171–1179. doi: 10.1161/01.cir.57.6.1171. [DOI] [PubMed] [Google Scholar]
- Wu D., Denes P., Dhingra R., Khan A., Rosen K. M. The effects of propranolol on induction of A-V nodal reentrant paroxysmal tachycardia. Circulation. 1974 Oct;50(4):665–677. doi: 10.1161/01.cir.50.4.665. [DOI] [PubMed] [Google Scholar]
- Wu D., Denes P. Mechanisms of paroxysmal supraventricular tachycardia. Arch Intern Med. 1975 Mar;135(3):437–442. [PubMed] [Google Scholar]

