The Electrophysiologic Characteristics in Patients with Only Ventricular-Pacing Inducible Slow–Fast Form Atrioventricular Nodal Reentrant Tachycardia (original) (raw)
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The American Journal of Cardiology, 2006
The inferior atrial extensions of the atrioventricular (AV) node have been related to the anatomic substrate of the slow pathway, but their role in AV nodal reentrant tachycardia (AVNRT) is unknown. Ten patients with slow-fast AVNRT were studied before and after successful slow pathway ablation. Simultaneous His bundle recordings from the right and left sides of the septum were made during right and left inferoparaseptal pacing. Longer stimulus to His (St-H) intervals were measured during right inferoparaseptal pacing than during left inferoparaseptal pacing (284 ؎ 55 vs 246 ؎ 46 ms, p ؍ 0.005 for right His recordings and 283 ؎ 56 vs 244 ؎ 46 ms, p ؍ 0.005 for left His recordings) at similar coupling intervals during AVNRT induction. After ablation, the St-H intervals at the maximum AV nodal conduction decrement were similar during right inferoparaseptal and left inferoparaseptal pacing (217 ؎ 32 vs 207 ؎ 21 ms, p ؍ 0.10 for right His and 215 ؎ 32 vs 206 ؎ 20 ms, p ؍ 0.13 for left His) at similar coupling intervals. The difference (⌬St-H) between St-H intervals during AVRNT induction or at the maximum conduction decrement and during constant pacing for right His recordings with right inferoparaseptal pacing were significantly greater than ⌬St-H measured with left His during left inferoparaseptal pacing (173 ؎ 64 vs 137 ؎ 55 ms, p ؍ 0.005) before ablation, but not after (117 ؎ 39 vs 100 ؎ 40 ms, p ؍ 0.44). Resetting of AVNRT with delivery of left inferoparaseptal extrastimuli was achieved in 7 of 10 patients. In conclusion, the electrophysiologic characteristics of the right and left inferior atrial inputs to the human AV node in patients with AVNRT and their response to slow pathway ablation provide further evidence that the inferior nodal extensions represent the anatomic substrate of the slow pathway.
Pacing and Clinical Electrophysiology, 1999
Ablation of Common Atrioventricular Nodal Reentrant Tachycardia./w^e tested the hypothesis that in some patients affected by typical AVNRT, successful catheter ablation treatment may be achieved independently of specific measurable electrophysiological modifications of antegrade AV node conducting properties. Standard electrophysiological parameters and comparable antegrade AV node function curves were obtained, before and after successful ablation, in 104 patients (mean age 52 ± 16 years; 69 women and 35 men) affected by the common form of AVNRT. The end point ofthe ablation procedure was noninducibility of AVNRT and of no more than one echo beat. For the purpose of this study, AVnode duality was defined as an increase of ^ 50 ms in the A2H2 interval in response to a 10 ms decrease ofthe A1A2 coupling interval. Refore ablation, AV node duality was present in 65 patients (62%) and absent in 39 patients (37%). Ablation caused measurable modifications of electrophysiological properties oftheAV node in most patients with elicited AV node duality, but not in most patients without demonstrable AV node duality. After ablation, AV node duality persisted in 20 patients who had it before, whereas a new duality that could not be elicited before appeared in 5 patients. During 19 ± 6 months of follow-up, clinical AVNRT recurred in 1 of 45 patients who had disappearance of AVnode duality after ablation, in 1 of 34 patients who did not show AV node duality before and after ablation, and in 1 of 20 patients who had persistence of AVnode duality after ablation. In conclusion, modifications of antegrade conduction properties of the AVnode are not crucial for the cure of AVNRT in many patients/ (PACE 1999; 22:263-267) AV nodal reentrant tachycardia, slow pathways, catheter ablation, electrophysiological study
Europace, 2010
To study anterograde atrioventricular (A-V) nodal electrophysiological properties through the right-atrial (Ri) and left-atrial inputs (Li) under the pharmacological autonomic blockade (AUB) in patients with slow-fast A-V nodal re-entrant tachycardia (AVNRT) and in controls. Methods and results Twenty-nine patients with slow-fast AVNRT and 15 control subjects were included. Programmed stimulation with single extrastimulus was performed from the right atrial appendage to test the Ri, and from the posterolateral coronary sinus to test the Li. The AUB was induced with intravenous atropine (0.04 mg/kg) and metoprolol (0.15 mg/kg). The A-V nodal conduction times, refractoriness, discontinuous conduction (≥40 ms atrial-His interval 'jump'), and inducibility of AVNRT or reciprocating beats were compared. The A-V nodal conduction times were longer: (i) through the Ri than Li, (ii) in patients than controls, and (iii) in baseline than after AUB-at slow rates in both groups and at fast rates in patients through the right input only (P , 0.05-0.001). A significantly longer slow pathway effective refractory period was demonstrated through the Li than the Ri in patients in baseline (P , 0.05). The discontinuous conduction was demonstrated 94 times in 25 of 29 (83%) patients and 15 times in 6 of 15 (40%) controls (P , 0.01), and was most frequently encountered with the Ri testing. Likewise, inducibility was manifested most frequently with the Ri testing (P ¼ 0.08), and decreased after AUB during this testing only (P ¼ 0.05). Conclusion The inherent magnitude of discordance of A-V nodal conduction velocity, refractoriness, and parasympathetic modulation between the Ri and Li to the A-V node may play a role in the aetiology of AVNRT.
Journal of Cardiovascular Electrophysiology, 1997
Methods and Results: Forty consecutive patients wbo underwent successful ablation of the slow pathway were prospective subjects for tbe study. Isoproterenol was used to enhance conduction and to differentiate interactive mechanisms. Potential electrotonic interactions were assessed by comparing patients with and tbose without residual dual AV node pbysiology after slow patbway ablation. Paired and unpaired f tests were used wben appropriate. P < 0.05 was considered statistically significant. In the entire study population, heart rates were not significantly different before and after slow pathway ablation (RR = 770 ± 114 msec before and 745 ± 99 msec after, P = 0.07). Anterograde fast pathway conduction properties were unchanged after slow pathway ablation (effective refractor> period, 348 ± 84 msec before and 336 ± 86 msec after, P = 0.13; shortest 1:1 conduction, 410 ± 93 msec before and 4(>0 ± 82 msec after, P = 0.39). Retrograde fast patbway cbaracteristics also were similar before and after ablation. Neither anterograde nor retrograde last patbway conduction properties during i.soproterenol infusion were changed by slow pathway ablation. When tbe study population was further divided into patients with (n = 13) or without (n = 27) residual dual AV node pbysiology, no significant change was detected in fast pathway function in either group after slow patbway ablation.
Journal of Cardiovascular Electrophysiology, 1993
AV Nodal Behavior After Ablation. Introduction; The objective of this report is to delineate the atrioventricular (AV) nodal electrophysiologic behavior in patients undergoing fast or slow pathway ablation for control of their AV nodal reentrant tachycardia (AVNRT).Methods and Results: One hundred sixteen consecutive patients with symptomatic AVNRT were included. Twenty-two patients underwent fast pathway ablation with complete abolition of AVNRT in all and development of complete AV block in five patients. Of 17 patients with intact AV conduction postablation, 12 had demonstrated antegrade dual pathway physiology during baseline study, which was maintained in three and lost in nine patients postablation. Two patients with successful fast pathway ablation developed uncommon AVNRT necessitating a slow pathway ablation. Twenty-one patients demonstrated both common and uncommon forms of AV nodal reentry during baseline study. The earliest site of atrial activation was close to the His-bundle recording site (anterior interatrial septum) during common variety and the coronary sinus ostium (posterior interatrial septum) during the uncommon AV nodal reentry in all 21 patients. Ninety-six patients underwent successful slow pathway ablation. Among these, the antegrade dual pathway physiology demonstrable during baseline study (60 patients) was maintained in 25 and lost in 35 patients postablation.Conclusion: These data suggest that: (1) dual pathway physiology may persist after successful ablation, which might be a reflection of multiple reentrant pathways in patients with AVNRT: and (2) the retrograde pathways during common and uncommon AVNRT have anatomically separate atrial breakthroughs. These findings have important electrophysiologic implications regarding the prevailing concept of the AV nodal physiology in patients with AVNRT.
Circulation, 2015
A trioventricular nodal reentrant tachycardia (AVNRT), which uses pathways within the atrioventricular node as critical limbs of reentrant circuits, has been divided among slow-fast, fast-slow (F/S), and slow-slow forms on the basis of the relative duration of atrio-His (AH) versus His-atrial (HA) conduction and the site of earliest atrial activation during the tachycardia. 1 F/S-AVNRT, characterized by a longer HA than AH interval and an earliest site of atrial activation in the posteroseptal region, incorporates a fast pathway (FP) as the anterograde limb and a typical slow pathway (SP) oriented inferiorly as the retrograde limb. 1 Several investigators, however, have described a rare subtype of F/S-AVNRT, with a site of earliest activation located in the superior aspect of the Koch triangle near the His bundle (HB), referred to here as sup-F/S-AVNRT, 2,3 which has not been widely accepted as a distinct supraventricular tachyarrhythmia. Furthermore, an atypical and distinct arrhythmogenic atrioventricular nodal substrate responsible for sup-F/S-AVNRT has not been confirmed electrophysiologically, although an atypical SP anterior to the FP has been suspected in rare cases of AVNRT. 4,5 This retrospective, multicenter study was designed to confirm the existence of a sup-F/S-AVNRT, with a focus on the presence and characteristics of a "superior" SP located in the HB region and used as the retrograde limb of the reentrant circuit. Clinical Perspective on p 123 Methods We retrospectively identified 6 women and 2 men 74±7 years of age (range, 59-82 years) who underwent successful ablation of a Background-The existence of an atypical fast-slow (F/S) atrioventricular nodal reentrant tachycardia (AVNRT) including a superior (sup) pathway with slow conductive properties and an atrial exit near the His bundle has not been confirmed. Methods and Results-We studied 6 women and 2 men (age, 74±7 years) with sup-F/S-AVNRT who underwent successful radiofrequency ablation near the His bundle. Programmed ventricular stimulation induced retrograde conduction over a superior SP with an earliest atrial activation near the His bundle, a mean shortest spike-atrial interval of 378±119 milliseconds, and decremental properties in all patients. sup-F/S-AVNRT was characterized by a long-RP interval; a retrograde atrial activation sequence during tachycardia identical to that over a sup-SP during ventricular pacing; ventriculoatrial dissociation during ventricular overdrive pacing of the tachycardia in 5 patients or atrioventricular block occurring during tachycardia in 3 patients, excluding atrioventricular reentrant tachycardia; termination of the tachycardia by ATP; and a V-A-V activation sequence immediately after ventricular induction or entrainment of the tachycardia, including dual atrial responses in 2 patients. Elimination or modification of retrograde conduction over the sup-SP by ablation near the right perinodal region or from the noncoronary cusp of Valsalva eliminated and confirmed the diagnosis of AVNRT in 4 patients each. Conclusions-sup-F/S-AVNRT is a distinct supraventricular tachycardia, incorporating an SP located above the Koch triangle as the retrograde limb, that can be eliminated by radiofrequency ablation.
Pacing and Clinical Electrophysiology, 1994
Atrial eiectrograms recorded from target sites during radiofrequency catheter ablation of the slow atrioventricular (AV) nodal pathway are often fractionated and may be associated with a late, high frequency component (the slow pathway potential). The purpose of the current study was to assess the effects of slow pathway ablation on the morphology of the atrial electrogram and to determine whether target site eiectrograms display direction dependent changes in morphology during atrial pacing maneuvers. Twenty-six patients with typical AV nodal reentry had eiectrograms recorded from target sites before and after successful ablation of the slow A V nodal path way and during pacing from the high right atrium and distal coronary sinus at cycle lengths of 500 and 300 msec. There was no significant change in the duration or degree of fractionation of the atrial electrogram as the result of slow pathway ablation. In contrast, the duration and degree of fractionation were less when pacing from the coronary sinus compared with sinus rhythms or right atrial pacing. Pacing rate did not affect electrogram morphology. These data suggest that the morphology of the slow pathway target site electrogram is dependent on the direction of atrial activation and that the "slow pathway potential" does not represent activation of an anatomically discrete pathway.
Journal of Cardiovascular Electrophysiology, 1998
AVNRT and Sinus Node Dysfunction, introduction: Sinus node dysfunction (SND) is frequently associated with impaired AV conduction. This study investigated the electrophysiologic properties of dual AV nodal pathways in patients suffering from both SND and AV nodal reentrant tachycardia (AVNRT). Methods and Results: Two j^roups of patients with slow-fast AVNRT underwent invasive electrophysiologic testing and catheter ablation of the slow pathway. Group A comprised 10 patients with SND (age 70 ± 8 years), (jlroup B included 10 age-matched patients without SND (age 69 ± 7 years; P = NS) who served as controls. Patients of group A exhihited prolongation of the anterograde Wenckebach cycle lengths (VVBCI.s) of hoth the fast pathway (559 ± 96 vs 361 ± 38 msec; P < 0.01) and the slow pathway (409 ± 57 vs 339 ± 32 ms; P < 0.01). However, the delta between the WBCLs of the fast and the slow pathways was larger in patients of group A (150 ± 80 vs 22 ± 20 msec; P 0,01). Retrograde fast pathway conduction was well preserved with no difference in WBCLs (356 ± 42 vs 330 ± 47 msec; P = NS). Cycle lengths of AVNRT were longer in group A (468 ± 46 vs 363 ± 37 msec; P < 0.01). Clinically, all patients of group A suffered from multiple episodes of AVNRT per week, which was not the case in any patient of group B (P < 0.01). Catheter ablation of the slow pathway eliminated AVNRT in all patients without complications. Conclusions: Patients with AVNRT and SND exhibit characteristic electrophysiologic alterations of both AV nodal pathways. Clinically, this results in significantly more frequent episodes of tachycardia. Slow pathway ablation appears to be safe and effective in these patients, f.