Europace (2003) 5, 225–229doi:10.1016/S1099–5129(03)00037-0Clinical and electrophysiological characteristicsin patients with atrioventricular reentrantand atrioventricular nodal reentrant tachycardiaN. Bottoni 1 , C. Tomasi 1 , P. Donateo 2 , G. Lolli 1 , N. Muià 1 , F. Croci 2 ,D. Oddone 2 , C. Menozzi 1 and M. Brignole 21 Unita` Operativa di Cardiologia Interventistica, Dipartimento di Cardiologia, Azienda OspedalieraS. Maria Nuova, Reggio Emilia, Italy; and 2 Centro Aritmologico, Dipartimento di Cardiologia,Ospedali del Tigullio, Lavagna, ItalyAim To compare clinical, electrophysiological characteristicsand transcatheter ablation results between two groupsof patients, one with atrioventricular reentrant tachycardia(AVRT) and the other with atrioventricular nodal reentranttachycardia (AVNRT).Methods The study population consisted of 94 consecutivepatients who underwent endocavitary electrophysiologicalstudy and radiofrequency (RF) ablation: 46 patients hadAVRT due to an accessory pathway with only retrogradeconduction while 48 patients had AVNRT.Results In relation to general and clinical characteristics,differences between the two groups emerged regarding theage of symptom onset (25 16 vs 37 17 years, p ¼ 0:001),the prevalence of heart disease (8 vs 31%, p ¼ 0:001) andthe correct diagnosis on surface ECG (50 vs 79%,p ¼ 0:001). Clinical presentation was quite similar apartfrom a higher prevalence of fatigue and sweating in theAVNRT group. Transcatheter RF ablation therapy resultswere similar.Conclusions Patients with AVRT have a lower mean ageat arrhythmia symptom onset compared with those withAVNRT and have fewer associated cardiac abnormalities.Clinical presentation is quite similar as well as their outcomeafter ablation. A correct diagnosis by standard ECGis more frequent in AVNRT.(Europace 2003; 5: 225–229)Ó 2003 The European Society of Cardiology. Published byElsevier Ltd. All rights reserved.Key Words: Paroxysmal supraventricular tachycardia,cardiac electrophysiology, transcatheter radiofrequencyablation, atrioventricular reentrant tachycardia, atrioventricularnodal reentrant tachycardia.IntroductionAtrioventricular nodal reentrant tachycardia (AVNRT)and atrioventricular reentrant tachycardia (AVRT) dueto a concealed accessory pathway are the most commonforms of paroxysmal tachycardias and together representabout 90% of regular supraventricular tachycardias(SVT)  . In patients undergoing endocavitary electrophysiologicalstudies, AVNRT are seen in about 70% ofManuscript submitted 12 June 2002, and accepted after revision27 March 2003.Correspondence: Nicola Bottoni, Unità Operativa di CardiologiaInterventistica, Azienda Ospedaliera S. Maria Nuova, V.Risorgimento 80, Reggio Emilia, Italy. Tel: +39-0522-296574;Fax: +39-0522-296288; E-mail: firstname.lastname@example.org, AVRT due to a concealed accessory pathwayin 20% and the remainder are atrial tachycardias  .Although these arrhythmias have long been known,there are relatively few studies in the literature thatcompare, in a systematic way, their clinical andelectrophysiological characteristics [3–11] . Moreover, thelarge majority of these studies consider as a single grouppatients with AVRT due to a concealed accessory pathwayand patients with AVRT by manifest accessorypathways; the latter group probably present a morecomplex symptomatic profile due to a greater tendencyto develop atrial fibrillation episodes [12–14] .The aim of the study was to compare clinical, electrophysiologicalcharacteristics and transcatheter ablationresults in two groups of patients, one with AVRT due toa concealed accessory pathway and the other withAVNRT.1099–5129/03/000225+05 $30.00/0 Ó 2003 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
AVRT and AVNRT patient characteristics 227Table 1Patients’ general and clinical characteristicsAVRT 46 patients AVNRT 48 patients pGender, males 65% 50% nsHeart disease 8% 31% ¼ 0.01Age of onset of PSVT (years) 25 16 37 17 ¼ 0.001Age at ablation (years) 48 14 53 16 nsSymptom duration (years) 22 16 17 13 nsAnnual incidence of PSVT 13 21 24 67 nsPSVT incidence in the past 12 months 38 68 51 100 nsCorrect ECG diagnosis* 50% 79% ¼ 0.001Minimal PSVT duration (mn.) 16 0 28 0 16 0 21 0 nsMaximal PSVT duration(mn.) 237 0 515 0 238 0 304 0 nsPrecipitating factors 30% 35% nsSpontaneous atrial fibrillation episodes 11% 8% nsAVRT, atrioventricular reentrant tachycardia; AVNRT, atrioventricular nodal reentrant tachycardia; PSVT, paroxysmal supraventriculartachycardia.*Diagnosis was based on RP 0 interval evaluation: tachycardia with RP 0 \70 ms was classified as AVNRT; tachycardia with RP 0 70 ms wasclassified as AVRT.pathway (one transient cerebral ischaemic attack andone episode of ventricular fibrillation, induced by a burstof premature ventricular complexes in a patient withischaemic heart disease during catheter manipulation)and 2% in patients with AVNRT (one transientatrioventricular block). There were no late complications.During the 12 6 month follow-up periodtachycardia recurrence was similar in the two groups;these patients underwent a successful additional procedure(Table 3).DiscussionThe aim of the present study was to compare clinical andelectrophysiological characteristics between two groupsof consecutive patients, one with AVRT due to concealedaccessory pathway and the other with AVNRT.The main results of the study can be summarized asfollows.Table 2PSVT symptom profileAVRT 46patientsAVNRT 48patientsPalpitation 100% 100% nsFatigue 24% 59% ¼ 0.001Dyspnoea 26% 46% nsPresyncope 50% 60% nsSyncope 8.7% 8.3% nsHeadache 2% 6% nsFeeling warm 4.3% 6.2% nsConfusion 6.5% 4.1% nsSweating 10.8% 37.5% ¼ 0.006Chest discomfort 21.7% 39.6% nsAVRT, atrioventricular reentrant tachycardia; AVNRT, atrioventricularnodal reentrant tachycardia; PSVT, paroxysmal supraventriculartachycardia.pPatients with AVRT had a lower mean age at thearrhythmia symptom onset compared with those withAVNRT and this finding is similar to that found byother authors [3,5,8–10,16] . The reason is not preciselyknown but it seems to be due to the fact that AVRT hasa well defined circuit tachycardia, which is congenitaland, therefore, has a greater probability of earlier activation,while AVNRT may require more time beforethe circuit pathways (slow nodal pathway, fast nodalpathway and perinodal atrium) acquire the electrophysiologicalproperties necessary to allow sustainedreentry.We observed a greater prevalence of organic heartdisease (especially the ischaemic-hypertensive type) inpatients with AVNRT. This finding was confirmed byother studies where, on average, 45% of the patientswith AVNRT and 18% with AVRT had heart disease[3,8,10] . This can possibly be explained by the factthat patients with AVNRT were older.A greater number of AVNRT were recognized on thesurface ECG compared with AVRT. To distinguish thetwo types of tachycardia we did not use any particularalgorithms  but only the RP 0 interval duration (a value\70 ms was indicative of nodal tachycardia and 70 msof concealed tachycardia). In our study population,many cases of AVRT had a RP 0 interval of nearly 70 msand were erroneously classified as AVNRT. The difficultyin correctly identifying the retrograde P wavecould have contributed to this diagnostic error.Although fatigue and sweating were seen morefrequently in patients with AVNRT, the symptomaticprofiles of the tachycardia were similar in the twogroups. In particular we did not see any significantdifference in the incidence of the episodes associatedwith haemodynamic instability and syncope. Haemodynamicdeterioration induced by the tachycardia wascorrelated with a higher heart rate and atrial contractionwith atrioventricular valves closed which are morecommonly seen in tachycardias with VA \200 ms andEuropace, Vol. 5, July 2003
228 N. Bottoni et al.Table 3Electrophysiological characteristics and catheter ablation resultsAVRT 46 patients AVNRT 48 patients pAH interval (ms) 77 16 85 24 ¼ 0.04HV interval (ms) 38.7 7.6 42.8 6.2 nsAntegrade AV node ERP (ms) 287 97 273 78 nsAtrial ERP (ms) 207 28 213 27 nsAntegrade WP (ms) 330 79 365 77 ¼ 0.03Retrograde AV node ERP (ms) 302 79 280 85 nsAtrial stimulation induction 81% 94% nsVentricular stimulation induction 66% 9% ¼ 0.001Baseline induction 91% 62% ¼ 0.002Isoprenaline induction 9% 38% ¼ 0.001Inducted PSVT cycle length (ms) 329 46 363 55 ¼ 0.002Atrial fibrillation induction 26% 25% nsNumber of RF applications 7.5 7.4 8.2 6.6 nsAblation success 91% 98% nsProcedural complications 4% 2% nsPSVT relapse 6% 6% nsAVRT, atrioventricular reentrant tachycardia; AVNRT, atrioventricular nodal reentrant tachycardia; PSVT, paroxysmal supraventriculartachycardia; AH, atrial potential–His potential interval; HV, His potential–ventricular potential interval; AV, atrioventricular; ERP,effective refractory period; WP, Wenckebach point; RF, radiofrequency.therefore in patients with AVNRT  . However, this wasnot confirmed in our study population. In accordancewith our findings, Wood et al.  noticed that theincidence of syncope was similar in the two types oftachycardia (16% in patients with AVNRT and 27% inpatients with AVRT; p ¼ ns) and was significantlycorrelated with a heart rate 170 bpm. It is, however,probable, as recently suggested  , that syncope duringtachycardia is due to vasovagal activation and that analtered cardiovascular reflex status plays a more importantrole in determining episodes of syncope duringtachycardia than the heart rate and the tachycardiamechanism.Regarding the electrophysiological characteristics,some differences between the two groups were seen inAH intervals, antegrade Wenckebach cycle and inducedtachycardia cycle length. A multivariate analysis was notperformed, but it is possible that these differencesderived from the different age of the two groups ofpatients and were not correlated with the mechanism ofthe arrhythmia. There were no significant differencesregarding other characteristics, such as gender, annualincidence, incidence during the year prior to ablation (asignificant increase was observed in both groups),duration of the tachycardia episodes, precipitatingfactors, association with spontaneous episodes of atrialfibrillation, rate of catheter ablation success, proceduralcomplication and late recurrence of the tachycardia.These findings are consistent with those reported in theliterature [3,5,7,10,13,20,21] .Study limitationThis study was conducted with a relatively small numberof patients and this could have rendered some differencesinsignificant between the two groups. Patienthistory was taken in some cases years after the beginningof the symptoms and might have been incorrectly givenby the patient. The study was conducted in tertiaryarrhythmological centres where the majority of patientsare more symptomatic and refractory to pharmacologicaltherapy and, therefore, may not reflect the truenatural history of patients with these types of tachycardiain the general population.References Josephson M, Buxton A, Marchlinski F. The tachyarrhythmias.In: Isselbacher K, Braunwald E, Wilson JD, eds.Harrison’s Principles of Internal Medicine. 13th edn. NewYork: McGraw-ill 1994: 1024–9. Calkins H, Sousa J, El-Atassi R, et al. Diagnosis and cure ofthe Wolff–Parkinson–White Syndrome or paroxysmal supraventriculartachycardias during a single electrophysiologic test.N Engl J Med 1991; 324: 1612–8. Wu D, Denes P, Amat-y-Leon F, et al. Clinical, electrocardiographicand electrophysiologic observations in patientswith paroxysmal supraventricular tachycardia. Am J Cardiol1978; 41: 1041–51. Sintetos AL, Roark SF, Smith MS, McCarthy EA, Lee KL,Pritchett EL. Incidence of symptomatic tachycardia in untreatedpatients with paroxysmal supraventricular tachycardia.Arch Intern Med 1986; 146: 2205–9. Rodriguez LM, de Chillou C, Schlapfer J, et al. Age at onsetand gender of patients with different types of supraventriculartachycardias. Am J Cardiol 1992; 70: 1213–5. Ko JK, Deal BJ, Strasburger JF, Benson DW Jr. Supraventriculartachycardia mechanisms and their age distribution inpediatric patients. Am J Cardiol 1992; 69: 1028–32. Clair WK, Wilkinson WE, McCarthy EA, Page RL, PritchettEL. Spontaneous occurrence of symptomatic paroxysmalatrial fibrillation and paroxysmal supraventricular tachycardiain untreated patients. Circulation 1993; 87: 1114–22. Hamer ME, Wilkinson WE, Clair WK, Page RL, McCarthyEA, Pritchett ELC. Incidence of symptomatic atrial fibrillationin patients with paroxysmal supraventricular tachycardia.J Am Coll Cardiol 1995; 25: 984–8. Goyal R, Zivin A, Souza J, et al. Comparison of the ages oftachycardia onset in patients with atrioventricular nodalEuropace, Vol. 5, July 2003
AVRT and AVNRT patient characteristics 229reentrant tachycardia and accessory pathway-mediated tachycardia.Am Heart J 1996; 132: 765–7. Wood KA, Drew BJ, Scheinman MM. Frequency of disablingsymptoms in supraventricular tachycardia. Am J Cardiol 1997;79: 145–9. Tada H, Oral H, Greenstein R, et al. Analysis of age of onsetof accessory pathway-mediated tachycardia in men andwomen. Am J Cardiol 2002; 89: 470–1. Della Bella P, Brugada P, Talajic M, et al. Atrial fibrillation inpatients with an accessory pathway: importance of theconduction properties of the accessory pathway. J Am CollCardiol 1991; 17: 1352–6. Chen SA, Chiang CE, Tai CT, et al. Longitudinal clinical andelectrophysiological assessment of patients with symptomaticWolff–Parkinson–White syndrome and atrioventricular nodereentrant tachycardia. Circulation 1996; 93: 2023–32. Bottoni N, Donateo P, Tomasi C, et al. Confronto dellecaratteristiche cliniche ed elettrofisiologiche dei pazienti convia accessoria atrioventricolare occulta e manifesta. Ital HeartJ Suppl 2001; 2: 888–93. Haïssaguerre M, Gaita F, Fischer B, et al. Elimination ofatrioventricular nodal reentrant tachycardia using discreteslow potentials to guide application of radiofrequency energy/contribution>. . Circulation 1992; 85: 2162–75. Akhtar M, Jazayeri MR, Sra J, Blanck Z, Deshpande S,Dhala A. Atrioventricular nodal reentry. Clinical, electrophysiological,and therapeutic considerations. Circulation 1993;88: 282–95. Tai CT, Chen SA, Chiang CE, et al. A new electrocardiographicalgorithm using retrograde P waves for differentiatingatrioventricular node reentrant tachycardia from atrioventricularreciprocating tachycardia mediated by concealed accessorypathway. J Am Coll Cardiol 1997; 29: 394–402. Goldreyer BN, Kastor JA, Kershbaum KL. The hemodynamiceffects of induced supraventricular tachycardia in man.Circulation 1976; 54: 783–9. Brembilla-Perrot B, Beurrier D, Houriez P, Claudon O,Wertheimer J. Incidence and mechanism of presyncope and/or syncope associated with paroxysmal junctional tachycardia.Am J Cardiol 2001; 88: 134–8. Jazayeri MR, Hempe SL, Sra JS, et al. Selective transcatheterablation of the fast and slow pathways using radiofrequencyenergy in patients with atrioventricular nodal reentranttachycardia. Circulation 1992; 85: 1318–28. Calkins H, Yong P, Miller JM, et al. Catheter ablation of accessorypathways, atrioventricular nodal reentrant tachycardia,and the atrioventricular junction final results of a prospective,multicenter clinical trial. Circulation 1999; 99: 262–70.Europace, Vol. 5, July 2003