Earliest Retrograde Atrial Activation Research Articles

Characteristics of Right-Sided Accessory Pathways Associated With Right Cardiac Veins.

The anatomy of myocardial fibers around the right cardiac veins (RCVs) and their roles in accessory pathways (APs) are rarely reported. Six RCV-APs were identified from 566 patients with right-sided APs. Mapping of retrograde atrial activation was performed using CARTO 3 system under orthodromic tachycardia or right ventricular pacing. Venography of RCVs was acquired at the earliest retrograde atrial activation. Patients enrolled had a median age of 30 (11-51) years, 5 of them were male. Venography of RCVs could be classified into 3 distinct patterns based on the identified ventricular branches, right marginal vein only (type I; n=3), both right marginal vein and anterior cardiac veins (type II; n=2), and anterior cardiac vein only (type III; n=1). Patients with type I venography had rS QRS pattern in lead V1, negative delta wave in lead III and negative or isoelectric delta wave in lead aVF. However, patients with type II and III venography had QS QRS patterns in lead V1 and variable patterns of delta wave in inferior leads. Earliest retrograde atrial activation was found at a median of 16.75 (14.60-20.00) mm away from the tricuspid annulus, all with A larger than V. At the earliest retrograde atrial activation, far-field ventricular electrogram was found 30 ms later than QRS onset in 1 patient under sinus rhythm. AP conduction was eliminated by mechanical pressure in 2 and by radiofrequency ablation in 4 at the ostium of the veins colocalizing with the earliest retrograde activation of the right atrium. No recurrence was observed during 36 (10-60) months follow-up. The RCV-AP is a rare form of right-sided APs characterized by atrial insertions distant from the annulus. ECG-speculated ventricular insertion sites conformed to the location of identified RCVs.

Left-sided accessory pathways successfully ablated from the aortomitral continuity region: distinctive atrial activation patterns and anatomic concerns.

Accessory pathways (APs) successfully ablated at the aortomitral continuity (AMC) were sporadically reported but relevant data are very limited. We aimed to describe the electrophysiological characteristics of AMC-AP and the related anatomy. This study involved eight (male/female = 3/5, mean age 42.6 ± 10.5 years) patients with left-sided AP successfully ablated in the AMC region. The retrograde atrial activation sequence was analysed and compared via recordings at the His-bundle (HB), coronary sinus (CS), and roving catheter during tachycardia, and the peak of QRS from the same cardiac circle used as time reference. Of the eight patients, two received prior ablations. During tachycardia, the activation time at the proximal CS (CSp), lateral CS (CSl), and HB region averaged 120 ± 26 ms, 124 ± 29 ms, and 117 ± 21 ms following the reference, respectively (P = 0.86). The latest atrial activation was recorded in the posterior CS which averaged 135 ± 25 ms following the reference. Placing the ablation catheter to AMC via retrograde approach was attempted in all cases but stable positioning achieved in none. Via transseptal approach, the ablation catheter could be easily placed at the AMC and recorded the earliest retrograde atrial activations with 60 ± 27 ms earlier than the relatively 'earliest' CS/HB recordings, and ablation at this site successfully eliminated AP conduction. No patients had recovered AP conduction after at least 12-month follow-up. AMC-AP is featured by recording comparable retrograde atrial activation times at CSp, CSl, and HB with the latest recordings at the posterior CS. Stable placement and successful ablation in the AMC via retrograde aortic approach was difficult but can be achieved via transseptal approach.

Transcatheter creation of a de novo communication across an extracardiac Fontan conduit for catheter ablation of a “left-sided” accessory pathway

Extracardiac polytetrafluoroethylene (PTFE) conduits are often used in modified Fontan procedures for separating systemic and pulmonary circulations in morphological and functional single ventricles [1]. However, most arrhythmia substrates of congenital and acquired supraventricular tachycardias will then be located ‘‘left-sided’’ across the extracardiac conduit. Remote magnetic navigation not only may facilitate a retrograde approach, but may also fail to reach the arrhythmia substrate [2]. Hybrid intervention consisting of transcatheter ablation via a sternotomy approach and atriotomy incision [3] as well as catheter ablation via direct transthoracic percutaneous access [4] have been described, but appear to be associated with frequent complications. An antegrade approach via femoral access requires special techniques for traversing the stiff PTFE material, the pericardial space and the atrial muscular wall. This is the first report that describes a modified transseptal puncture technique using no more than mechanical force [5] for successful catheter ablation across an extracardiac PTFE Fontan conduit. A 23-year-old male patient with double-outlet right ventricle, mitral atresia, severe left ventricular hypoplasia, subpulmonary ventricular septal defect, valvular pulmonary stenosis and D-transposition of the great arteries after modified Fontan anastomosis presented with a 15-year history of recurrent supraventricular tachycardia. Bidirectional superior cavopulmonary anastomosis (Glenn) had been performed at the age of 6 years, modified Fontan anastomosis with an extracardiac non-fenestrated 19 mm PTFE conduit connecting the inferior vena cava and the pulmonary arteries 2 years later. Tricuspid valve (TV) repair employing an anuloplasty ring was carried out for tricuspid regurgitation at the age of 17 years. Despite various oral antiarrhythmic medications [propafenone (up to 600 mg per day, 13 mg/kg per day); propafenone (up to 600 mg per day, 13 mg/kg per day) plus bisoprolol (2,5 mg per day) plus digoxin (aiming at serum levels of 1–2 ng/ ml); sotalol (up to 320 mg per day, 5 mg/kg per day); sotalol (160 mg per day) plus digoxin (aiming at serum levels of 1–2 ng/ml)], the patient continued to experience recurrent adenosine-sensitive supraventricular tachycardias (cycle length 340 ms). After discontinuation of antiarrhythmic medication, electrophysiology testing was performed with one steerable quadripolar catheter placed retrograde across the aortic valve in a right ventricular (RV) position and with one steerable decapolar catheter at the junction of the left pulmonary artery and the calcified extracardiac conduit where atrial sensing and pacing was possible. A supraventricular tachycardia (cycle length 350 ms) characteristic for orthodromic atrioventricular reciprocating tachycardia (AVRT) was easily induced by programmed ventricular pacing (Fig. 1a, b). Electroanatomical mapping of earliest retrograde atrial activation during tachycardia was performed using the EnSite Velocity Cardiac Mapping System (EnSite NavX, St. Jude Medical, St. Paul, MN, USA). Using the steerable quadripolar catheter placed retrograde across the aortic valve, the G. Kerst (&) D. Schranz M. B. Gonzalez y Gonzalez Department of Pediatric Cardiology, Pediatric Heart Center Giessen, University Children’s Hospital, Feulgenstr. 10-12, 35392 Giessen, Germany e-mail: gunter.kerst@paediat.med.uni-giessen.de

Occurrence of atrioventricular block during supraventricular tachycardia: What is its possible mechanism?

A female patient was admitted to our hospital for catheter ablation arising from paroxysmal supraventricular tachycardia (PSVT). In the laboratory, PSVT (the earliest retrograde atrial activation at the coronary sinus ostium) with intermittent atrioventricular (AV) block could be induced repeatedly. The tachycardia could be terminated during ventricular pacing without retrograde conduction to the atria. Therefore, orthodromic AV reciprocating tachycardia (AVRT) and atrial tachycardia (AT) could be ruled out and AV nodal re-entrant tachycardia (AVNRT) was subsequently considered. Initial attempts using slow or intermediate AV nodal ablation failed to cure the tachycardia. We considered the possibility of orthodromic AV reciprocating tachycardia (AVRT) with AV block occurring during the tachycardia. The tachycardia was successfully terminated during the ablation of the right posteroseptal pathway at the coronary sinus ostium. We hypothesized about the possible explanation that might help to clarify the phenomenon of AV block during SVT in order to provide some guidance to other clinicians confronted with similar patient challenges in the future.

Ablation of Left‐Sided Accessory Pathways with Atrial Insertion Away from the Mitral Annulus Using an Electroanatomical Mapping System

A left-sided accessory pathway (AP) with atrial insertion away from the mitral annulus (MA) may result in difficulty or failed ablation along the MA. We report our initial experience of ablating this rare form of AP by a 3-dimensional electroanatomical mapping system (CARTO). From January 2007 to August 2011, 29 patients with left-sided APs who failed previous ablations in other centers were enrolled in this study. Left atrium (LA) was reconstructed during orthodromic atrioventricuar reentry tachycardias (AVRTs) or ventricle pacing by using a 3-dimensional electroanatomical mapping system. The AP atrial insertion was defined as the earliest retrograde atrial activation and successful ablation of the AP at the site. Among the 29 patients who had failed previous ablation, 7 patients were found to have atrial insertions away from the MA. Out of the 7 patients, atrial insertions were at the base of the LA appendage in 5 patients and at the anterior roof of LA in 2 patients. Ablation at the atrial insertion successfully abolished AP conduction. The mean distance between the atrial insertion sites and the MA was 24.9 ± 4.9 mm. No patients reported recovered AP conduction or recurrent tachycardias after at least 12-month follow-up. Left-sided APs may have atrial insertions away from the MA. By using the CARTO system, atrial insertions can be reliably identified and ablated.

Radiofrequency Catheter Ablation of Posterior Paraseptal Accessory Pathway with Atresia of the Coronary Sinus Ostium

A 42-year-old man was referred to our hospital for an electrophysiologic study because of recurrent episodes of palpitation. On coronary angiogram, an anomalous atresia of the coronary sinus (CS) ostium was discovered. The ablation catheter was inserted from the right femoral artery to the accessory pathway (AP) of posterior paraseptal area. The earliest retrograde atrial activation was recorded in the 5-6 o'clock region of the mitral annulus. Radiofrequency energy was delivered to this site, resulting in elimination of the AP. After this application, there was persistent ventriculoatrial dissociation and led to successful ablation of the AP.

Cycle Length-Dependent Retrograde Conduction over a Concealed Atrioventricular Accessory Pathway

A 78-year-old man had recurrent episodes of tachycardia and was referred for radiofrequency ablation. An ECG recorded showed a narrow QRS tachycardia with a cycle length of 270 ms, during which pseudo r was observed in V1 lead, suggesting that the tachycardia is due to atrioventricular nodal reentrant tachycardia. At electrophysiological study, ventricular extrastimulus testing was performed with a basic drive cycle length of 600 ms. At coupling intervals of 460 ms to 340 ms, the earliest retrograde atrial activation was recorded from His bundle region, with decremental conduction property. At coupling intervals of 330 ms to 280 ms, ventricullar-atrial (VA) conduction time abruptly shortened (310 ms to 140 ms), and the earliest retrograde atrial activation transferred to the orifice of the coronary sinus with no decremental conduction property. At coupling intervals at 270 ms or less, VA conduction time prolonged (144 ms to 383 ms). The earliest retrograde atrial activation returned to His bundle resion with decremental conduction property. After radiofrequency ablation targeting antegrade slow pathway, both antegrade AV slow pathway conduction and short VA conduction disappeared. We consider that the existence of cycle length-dependent retrograde conduction over a concealed accessory atrioventricular pathway could explain our phenomenon. As cycle length-dependent retrograde conduction over a concealed accessory pathway is rare, the possible mechanisms of which should be carefully discussed.

Fast-Fast form of Atypical AV Nodal Reentrant Tachycardia: Incidence, Electrophysiological Characteristics and Results of Catheter Ablation

Background: Both typical and atypical AV nodal reentrant tachycardias (AVNRT) are usually amenable to slow pathway (SP) ablation at the inferoseptal areas. However, rare cases of unusual forms of AVNRT are resistant to SP ablation and their characteristics remain to be elucidated. Methods and Results: Total of 1252 AVNRTs induced in 950 cases were reviewed. Both anterograde and retrograde limbs of tachycardia circuit (TC) were classified into fast pathway (FP) or SP according to the A-H (AHI) and H-A intervals (HAI) during the tachycardia; the anterograde FP (AHI ⁄= 220 msec), and retrograde FP (HAI ⁄= 120 msec). Accordingly, the 1252 AVNRTs were classified into slow-fast (S/F: n=998), slow-slow (S/S: n=119), fast-slow (F/S: n=129) and fast-fast (F/F: n=6) forms. The F/F forms were induced by atrial or ventricular extrastimulation without associated jump-up in the AHI and HAI, and they were characterized by shorter tachycardia cycle length (260±55 msec), short AHI (153±39 msec) and HAI (107±19 msec) during the tachycardia and earliest retrograde atrial activation at the right superoseptum (n=2) or midseptum (n=4). The tachycardias were entrained from the RV and resumed with V-A-V sequence after cessation of entrainment pacing. SP ablation at right inferoseptum was unsuccessful in all F/F forms. Successful ablation was achieved at right superoseptum (n=2) or midseptum (n=4) without creating AV block. Conclusions: F/F forms of AVNRT not involving SP in TC were observed in 0.5% of all AVNRT. It was suggested the TC was smaller and confined to the superior part of AV nodal area in this extremely rare form of AVNRT.

Radiofrequency Catheter Ablation of Posterior Paraseptal Accessory Pathway with Atresia of the Coronary Sinus Ostium

Atresia of coronary sinus (CS) ostium is a rare abnormality and only a few case reports in association with electrophysiological studies. These patients have been reported to have a variety of several arrhythmogenic sources. A 42-year-old man was referred to our hospital for an electrophysiologic study because of recurrent episodes of palpitation. A 6-French decapolar catheter was introduced from the right jugular vein and advanced to the near the CS ostium. But, we could not be advance the catheter into the CS despite several attempts. On coronary angiogram, an anomalous atresia of the CS ostium was discovered. Regular tachycardia was easily induced by an atrial stimulus, we suggested the patient had an atrioventricular reentrant tachycardia. During the tachycardia, the earliest retrograde atrial activation was recorded in the 5–6 o’clock region of the mitral annulus. The ablation catheter was inserted from the right femoral artery to the accessory pathway (AP) of posterior paraseptal area. Radiofrequency energy was delivered to this site, resulting in elimination of the AP. After this application, there was persistent ventriculo-atrial dissociation and led to successful ablation of the AP. We report a rare case of the ablation procedure of posterior paraseptal AP with atresia of the CS ostium.

Ablation of Right-Sided Accessory Pathways With Atrial Insertion Far From the Tricuspid Annulus Using an Electroanatomical Mapping System

It is difficult to ablate a right-sided accessory pathway (AP) with atrial insertion far from the tricuspid annulus (TA). We report our initial experience of ablating this rare AP by a 3-dimensional electroanatomical mapping system (CARTO). From January of 2006 to April of 2008, 18 patients with right-sided APs who failed previous outside ablations were enrolled in this study. Retrograde AP conduction was mapped during pacing at the right ventricular apex by activation-mapping the right atrium (RA) using a 3-dimensional electroanatomical mapping system. AP atrial insertion was defined as the earliest retrograde atrial activations and successful ablation of the APs at this site. Among the 18 patients who had failed previous ablation, 10 patients (7 patients with right manifest APs and 3 patients with right conceal APs) had atrial insertions far from the TA. Of the 10 patients, the atrial insertions were found at the base of the RA appendage in 3 patients, at the high lateral RA in 5 patients, at the low lateral RA in other 2 patients. Ablation at the atrial insertions successfully abolished the AP conduction. The mean distance between the atrial insertion sites and the TA was 20.2 ± 2.7 mm. No patients reported recovered AP conduction or recurrent tachycardias after 6-month follow-up. The right-sided APs may have atrial insertion far from the TA. These uncommon variation of APs can be reliably identified and ablated using CARTO system.

Electrophysiological and clinical characteristics of atrioventricular nodal reentrant tachycardia and longterm success of radiofrequency catheter ablation

Background: Diff erent reentry circuits within A-V node region are able to sustain A-V nodal reentrant tachycardia (AVNRT). On this basis, electrophysiological criteria for at least three AVNRT types – slow/fast, fast/slow, and slow/ slow–have been proposed. Th e aim was to reevaluate these criteria in a group of our patients. In addition, clinical profi le and long-term success rate of catheter ablation procedure were studied. Methods: All consecutive patients referred for catheter ablation of AVNRT from September 2004 to December 2006 were prospectively recruited. Th e informed consent was signed by all and the study had been approved by the competent state’s ethics committee. A standard electrophysiological study with programmed single or double extrastimuli or high-rate electrostimulation until the development of refractoriness or tachycardia induction was performed. Orciprenaline i.v. was used to facilitate AVNRT induction and to test the ablation result. Slow-pathway electrograms at inferoposteroseptal right atrium and ablation-induced nodal rhythm were ablation targets. Th e radiofrequency energy of 30–50 W for a duration of at least 20 seconds was used. Non-inducibility of AVNRT and of echo-beats was the procedure end point. In addition, antegrade and retrograde A-V junction conduction times were measured and analysed manually. Patients underwent a detailed re-evaluation aft er at least 1 year of follow-up. Th e descriptive statistic was used to present the data. Results: One hundred and four patients, 72 % female, mean age 53 years, were included. Th ey had their fi rst tachycardia episode at a mean age of 35 years with an average recurrence rate of 1- to 3-times a year. Syncope was experienced in 9.5 % of patients. Familial tachycardias were reported in 4 % of patients. One third (34 %) were hypertensive (≥ 140/90 mmHg). In majority, slow/fast AVNRT type (98/104–94 %) was induced. Th e fast/slow and slow/slow types were rare (3/104 each). Th e mean heart rate of induced AVNRT was 166 beats/min. Measurements were available for 92 patients. Our best diagnostic criteria were: V-A’interval ( 150 fast/slow, 70–120 slow/slow), H-A’interval ( 200 fast/slow; 120–170 slow/ slow), and A’-H/H-A’ ratio (> 2,3 slow/fast, < 1 fast/slow, 1–2,3 slow/slow). Th e slow/fast type was generally induced from the atrium, while the fast/slow and slow/slow also from the ventricle. In the slow/fast type, the earliest retrograde atrial activation was recorded from the His bundle position in 95 % (proximal coronary sinus (CS) in 5 %). Th e earliest retrograde atrial activation was recorded from proximal CS in the fast/slow type, but from CS or His in the slow/slow. A transient A-V block was documented in 6 patients during ablation procedure. None of them needed a permanent pacemaker implantation. Aft er 16 months of follow-up, 96 % of our patients were free of tachycardia recurrences. Conclusions: Electophysiologic criteria for three AVNRT types, clinical characteristics, and AVNRT long-term radiofrequency catheter ablation success rate are consistent with data reported in the literature.

Abstract 5678: Fast-Fast Form of Atypical AV Nodal Reentrant Tachycardia: Incidence, Electrophysiological Characteristics and Results of Catheter Ablation

Both the typical (slow-fast (S/F)) and atypical (slow-slow (S/S) and fast-slow (F/S)) forms of the AV nodal reentrant tachycardias (AVNRT) are usually amenable to the classical slow pathway (SP) ablation at the inferoseptal atrial region. However, rare cases of unusual forms AVNRT do not involve an SP in the tachycardia circuits (TC), and they are resistant to the classical SP ablation. The characteristics of the atypical AVNRTs not involving an SP in the TCs remain to be elucidated. A total of 1252 AVNRTs induced during the electrophysiological study in 950 cases were analyzed. Both the anterograde and retrograde limbs of the TC were classified into the fast pathway (FP) or SP according to the A-H (AHI) and H-A intervals (HAI) during the tachycardia; the anterograde FP: AHI of &lt;220 ms, anterograde SP: AHI of ≥220 ms, retrograde FP: HAI of &lt;120 ms, and retrograde SP: HAI of ≥120 ms. Accordingly, each tachycardia was classified into one of the S/F, S/S, F/S and fast-fast (F / F) forms . There were 998 S/F forms (79.7%), 119 S/S forms (9.5%), 129 F/S forms (10.3%) and 6 F / F forms (0.5%). The F / F forms were induced by atrial or ventricular extrastimulation without an associated jump-up in the AHI and HAI, and they were characterized by a shorter tachycardia cycle length (260±55 ms), short AHI (153±39 ms) and HAI (107±19 ms) during the tachycardia, earliest retrograde atrial activation (ERAA) at the right superoseptum (n=2) or midseptum (n=4), and 2nd degree AV block without a tachycardia interruption. The retrograde atrial activation sequence during the F / F forms was identical to that during ventricular pacing. The tachycardias could be entrained from the RV, and they resumed with a V-A-V sequence after the cessation of the entrainment pacing. The classical SP ablation at the right inferoseptal region was unsuccessful in all 6 cases with the F / F forms . The successful ablation was achieved at the right superoseptum (n=2) or midseptum (n=4) without creating AV block in all 6 cases. The F / F forms of atypical AVNRT not involving a classical SP in the TC were observed in 0.5% of all AVNRT cases. The results of this study suggested that the TC was smaller and confined to the superior part of the AV nodal area in this extremely rare form of AVNRT.

Superior Type of Atypical AV Nodal Reentrant Tachycardia: Incidence, Characteristics, and Effect of Slow Pathway Ablation

Atypical atrioventricular (AV) nodal reentrant tachycardias (AVNRT) usually exhibit the earliest retrograde atrial activation (ERAA) at the right inferoseptum (Rt-IS) or proximal coronary sinus (PCS). The purpose of this study was to characterize atypical AVNRT with the ERAA at the right superoseptum (Rt-SS). Seventy-three atypical AVNRTs induced in 63 cases were classified into the superior type with the ERAA at the Rt-SS and inferior type with the ERAA at the Rt-IS or PCS. There were nine superior (12%) and 64 inferior types of atypical AVNRT (88%) in seven and 56 cases, respectively. The superior type exhibited a short atrial-His interval during the tachycardia (166 +/- 41 ms), long His-atrial interval during the tachycardia (H-At:156 +/- 38 ms), and ventricular pacing at the tachycardia cycle length (TCL) (H-Ap:201 +/- 36 ms), and evidence for a lower common pathway, including second-degree AV block (four tachycardias) and an H-Ap being longer than the H-At (nine tachycardias). The TCL was shorter in the superior type than in the inferior type (322 +/- 35 vs 404 +/- 110 ms; P < 0.02). In the inferior type, all tachycardias were eliminated after the ablation at the Rt-IS (44 tachycardias) or PCS (20 tachycardias) where an ERAA was recorded. In the superior type, ablation at the Rt-IS was ineffective; however, ablation at the right midseptum eliminated seven (78%) of the nine tachycardias. The tachycardia circuit of the superior type might have deviated to a more superior part of Koch's triangle than that of the inferior type.

Abstract 1541: Atypical Atrioventricular Nodal Reentrant Tachycardia with Anterior Retrograde Slow Pathway: Incidence, Electrophysiological Characteristics and Effect of Slow Pathway Ablation

BACKGROUND: Atypical AV nodal reentrant tachycardias (AVNRT) usually exhibit earliest retrograde atrial activation (ERAA) at the right posteroseptum (Rt-PS) or proximal coronary sinus (PCS). However, previous studies have shown that atypical AVNRT could rarely exhibit ERAA at the right anteroseptum (Rt-AS). The purpose of this study was to elucidate the incidence, characteristics and effect of slow pathway (SP) ablation in atypical AVNRT with an anterior retrograde SP. METHODS: The electrophysiological and ablation data were reviewed in 360 AVNRTs induced in 340 consecutive patients. Atypical AVNRT was differentiated from typical form by a longer H-A interval during ventricular pacing at the tachycardia cycle length (TCL) (HAp: =/&gt;70ms), and evidences for a lower common pathway (LCP), including second-degree AV block without tachycardia interruption, HAp longer than the HA interval during tachycardia (HAt). Atypical AVNRTs were classified into two types; the posterior type with ERAA at the Rt-PS or PCS; and anterior type with ERAA at the Rt-AS. RESULTS: In a total of 360 AVNRTs, there were 300 typical (83%) and 60 atypical forms (17%). Among the 60 atypical forms, 51 (14%) were classified into the posterior type, while the remaining 9 (3%) were classified into the anterior type. The anterior type of atypical AVNRT (TCL: 322+/−37ms) exhibited ERAA at the Rt-AS during the tachycardia and ventricular pacing, shorter A-H interval (162+/−39ms), longer HAt (167+/−40 ms), longer HAp (184+/−53ms), and evidences for a LCP, including a second-degree AV block during the tachycardia (n=4) and HAt being shorter than the H-Ap (n=9). All posterior types of atypical AVNRT were rendered non-inducible after an ablation to the ERAA site. In anterior type, the conventional SP ablation at the Rt-PS did not eliminate any of the 9 tachycardias; however, ablations at the right midseptum eliminated 7 (78%) of the 9 anterior types of atypical AVNRT. CONCLUSION: Atypical AVNRT with an anterior retrograde SP was observed in 3% of all AVNRTs. Conventional Rt-PS ablation was ineffective; and the midseptal ablation was modestly effective in this entity. The tachycardia circuit of the anterior type might be deviated to more anterior part of the Koch’s triangle than that of the posterior type.

Retrograde slow pathway conduction in patients with atrioventricular nodal re-entrant tachycardia

To study retrograde slow pathway conduction by means of right- and left-sided septal mapping. Nineteen patients with slow-fast atrioventricular nodal re-entrant tachycardia (AVNRT) were studied before and after slow pathway ablation. Simultaneous His bundle recordings from right and left sides of the septum, using trans-aortic and trans-septal electrodes, were made during right ventricular pacing. Pre-ablation, decremental retrograde ventriculo-atrial (VA) conduction without jumps or discontinuities was recorded in eight patients (group 1). In six patients, retrograde conduction jumps were demonstrated (group 2) and in the remaining four patients, there was minimal prolongation of stimulus to atrium (St-A) intervals (group 3). The maximal difference (Delta St-A) between St-A intervals obtained with pacing at a constant cycle length of 500 ms and at the cycle length with maximal retrograde VA prolongation was significantly longer measured from the right His compared with the left His (122 +/- 25 vs. 110 +/- 33 ms, P = 0.02, respectively) in group 1 and group 2 (140 +/- 23 vs. 110 +/- 35 ms, P = 0.03), but not in group 3 (10 +/- 4 vs. 13 +/- 8 ms, P = 0.35). Post-ablation, Delta St-A intervals were similar between right and left His recordings (77 +/- 37 vs. 76 +/- 33 ms, P = 0.53, respectively) in group 1, (100 +/- 24 vs. 103 +/- 21 ms, P = 0.35) group 2, and (63 +/- 32 vs. 66 +/- 33 ms, P = 0.35) group 3. In patients with typical AVNRT, retrograde conduction through the slow pathway results in earliest retrograde atrial activation on the left side of the septum and catheter ablation in the right inferoparaseptal area abolishes this pattern. These findings are compatible with the concept of slow pathway conduction by means of the inferior AV nodal extensions.

P3-110: Wpw and fabry’s disease: Evidence for atrioventricular and atriohisian accessory pathway conduction

Anderson Fabry’s disease (FD) is a X- linked recessive disorder due to alpha-galactosidase A deficiency. Atrial fibrillation (AF) and conduction diseases have been associated with FD. We report the first case to our knowledge of FD with AF and WPW involving multiple accessory pathways (AP). Case: A 56-year-old male with FD presented with palpitation and preexcited AF suggestive of a left sided AP. At EP testing, he was in sinus rhythm with a short AH (26 ms) and HV (28 ms) interval. Retrograde VA conduction was central and decremental, but the HA remained constant (68ms) and the earliest retrograde atrial activation was in the high right atrium.

Unique electrophysiologic characteristics of atrioventricular nodal reentrant tachycardia with different ventriculoatrial block patterns: Effects of slow pathway ablation and insights into the location of the reentrant circuit

The electrophysiologic mechanisms of different ventriculoatrial (VA) block patterns during atrioventricular nodal reentrant tachycardia (AVNRT) are poorly understood. The purpose of this study was to characterize AVNRTs with different VA block patterns and to assess the effects of slow pathway ablation. Electrophysiologic data from six AVNRT patients with different VA block patterns were reviewed. All AVNRTs were induced after a sudden AH "jump-up" with the earliest retrograde atrial activation at the right superoparaseptum. Different VA block patterns comprised Wenckebach His-atrial (HA) block (n = 4), 2:1 HA block (n = 1), and variable HA conduction times during fixed AVNRT cycle length (CL) (n = 1). Wenckebach HA block during AVNRT was preceded by gradual HA interval prolongation with fixed His-His (HH) interval and unchanged atrial activation sequence. AVNRT with 2:1 HA block was induced after slow pathway ablation for slow-slow AVNRT with 1:1 HA conduction, and earliest atrial activation shifted from right inferoparaseptum to superoparaseptum without change in AVNRT CL. The presence of a lower common pathway was suggested by a longer HA interval during ventricular pacing at AVNRT CL than during AVNRT (n = 5) or Wenckebach HA block during ventricular pacing at AVNRT CL (n = 1). In four patients, HA interval during ventricular pacing at AVNRT CL was unusually long (188 +/- 30 ms). Ablations at the right inferoparaseptum rendered AVNRT noninducible in 5 (83%) of 6 patients. Most AVNRTs with different VA block patterns were amenable to classic slow pathway ablation. The reentrant circuit could be contained within a functionally protected region around the AV node and posterior nodal extensions, and different VA block patterns resulted from variable conduction at tissues extrinsic to the reentrant circuit.

Localization of the ventricular insertion site of concealed left-sided accessory pathways using ventricular pace mapping.

The aim of the present study was to localize the ventricular insertion site of concealed accessory pathway (APs) by using the ventricular pace mapping and examined if the analysis of the timing of retrograde atrial electrogram recorded at the ventricular side of the mitral annulus is useful in identifying the ventricular insertion site of the AP. In 39 patients with concealed left-sided APs, ventricular pacing was delivered along the mitral annulus at a cycle length of 500 ms while measuring the conduction interval from the pacing stimulus to the earliest retrograde atrial electrogram recorded in the coronary sinus (St-A). The ventricular insertion site of the AP was localized by identifying the shortest St-A. Also the interval between the onsets of QRS and atrial electrograms (QRS-A) and presence of continuous electrical activity (CEA) between the ventricular and atrial electrograms were evaluated at each mapping site during atrioventricular reciprocating tachycardia. Initial radiofrequency energy application to the site with the shortest St-A (46 +/- 15 ms) eliminated the AP conduction in all patients, suggesting the accurate localization of the ventricular insertion site by ventricular pace mapping. The QRS-A and the percentage of the presence of CEA at the shortest St-A site were 79 +/- 19 ms and 64%, respectively. However, the earliest retrograde atrial activation site did not coincide with the shortest St-A site in 19 of 39 patients, suggesting an oblique course of AP. Thus, in these 19 patients, there was a significant difference in St-A (47 +/- 16 vs 59 +/- 15 ms, P < 0.0001), QRS-A (83 +/- 13 vs 72 +/- 12 ms, P < 0.0001) and the presence of CEA (32 vs 74%, P < 0.01) between the shortest St-A site and the earliest retrograde atrial activation site, respectively. These indicate that the earliest retrograde atrial activation is not necessarily indicative of the ventricular insertion site of AP. However, ventricular pace mapping was considered to be useful for identifying and ablating the ventricular insertion site of AP, irrespective of the course of AP.

Radiofrequency application to the posteroseptal region alters retrograde accessory pathway activation.

Radiofrequency applications to the posteroseptal region can ablate the atrioventricular accessory pathway residing in this area. In conjunction with the adjacent anatomic structures, however, ablative lesions which do not effectively ablate the accessory pathway could markedly alter retrograde atrial activation sequence and confound interpretation of further mapping of an accessory pathway. Electrophysiologic studies, endocardial activation mapping and radiofrequency catheter ablation were undertaken in three patients with recurrent supraventricular tachycardia. Patients were initially thought to have a single posteroseptal accessory pathway; earliest ventrioatrial activation during tachycardias and during ventricular pacing was at the coronary sinus ostium, but initial radiofrequency applications were unsuccessful to ablate the pathway. After initial radiofrequency applications to the posteroseptal region, the earliest retrograde atrial activation changed to the right atrial free wall in two patients. Additional radiofrequency application to the posteroseptal area was able to ablate the single posteroseptal accessory pathway in one patient. Radiofrequency application to the right atrial free wall was required to stop tachycardia initiation in other patient. The third patient was suspected of having a slow-slow atrioventricular nodal reentry tachycardia. Radiofrequency application to the posteroseptal area changed the earliest retrograde atrial activation to the distal coronary sinus recording site, mimicking an accessory pathway at the left atrial free wall. Radiofrequency application to the anteroseptum was able to ablate the concealed accessory pathway. Radiofrequency applications to the posteroseptal region can markedly alter retrograde atrial activation, thereby confounding further mapping of the accessory pathway.

Presence and significance of the left atrionodal connection during atrioventricular nodal reentrant tachycardia

It has been suggested that the anatomic substrates of dual atrioventricular nodal pathways are likely to be the atrionodal connections. During atrioventricular nodal reentrant tachycardia (AVNRT) or ventricular pacing (VP), an earliest retrograde atrial activation in the coronary sinus (CS) distal to the ostium (CS breakthrough) would suggest the presence of an exit from a left atrionodal connection. The aim of the study was to evaluate the incidence of such an atrial retrograde activation in the CS during AVNRT and VP. The retrograde atrial activation was recorded during typical AVNRT (38 patients, 27 women, mean age 44 ± 18 years) by a multipolar catheter in the CS, a decapolar catheter in the His bundle position, and a deflectable quadripolar catheter along the tricuspid annulus anterior to the CS ostium. In 31 patients the retrograde atrial activation was recorded also during VP at a similar cycle length. A CS breakthrough was found in 18 patients during AVNRT (47%) and in 13 patients during VP (42%). Presence or absence of CS breakthrough was concordant between AVNRT and VP in 90% of the patients. A CS breakthrough, suggesting a left-sided atrionodal connection, is frequently recorded both during AVNRT and VP. In patients with a CS breakthrough pattern, the absence of correlation between the His bundle to the earliest CS retrograde atrial electrogram interval and AVNRT cycle length, or any other atrial activation times recorded in the posterior and anterior region of the Koch’s triangle, would suggest that the left-sided atrionodal connection is a bystander during typical AVNRT.