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Shih-Ann Chen

Publications and source records attributed to Shih-Ann Chen.

At least 19 recordsLinked to original sources
PubMed2006

The electrophysiologic characteristics of atrioventricular nodal reentry tachycardia with eccentric retrograde activation.

BACKGROUND: The occurrence of eccentric retrograde atrial activation has been demonstrated to be from 6 to 8% in patients with atrioventricular nodal reentrant tachycardia (AVNRT) by several previous reports. However, most of those reports were limited by the absence of coronary sinus venography to confirm if the retrograde activation was truly left sided. The purposes of this study were to 1) determine the incidence of left sided retrograde atrial activation in our center, 2) determine the specific electrophysiologic characteristics of eccentric and concentric atrial activation and 3) determine the outcome of radiofrequency catheter ablation for AVNRT with eccentric retrograde atrial activation. METHODS: From November 2001 to July 2004, 290 consecutive patients with AVNRT who underwent an electrophysiologic study and radiofrequency ablation were included. Group 1 consisted of AVNRT patients with eccentric retrograde atrial activation; group 2 consisted of AVNRT patients with concentric retrograde atrial activation. The electrophysiologic characteristics of the group 1 and group 2 patients were then compared. RESULTS: The incidence of AVNRT with eccentric retrograde activation confirmed by CS venography was 6.5%. There were more females and atypical AVNRT in patients with retrograde eccentric conduction. There was more VA block after ablation and tachycardia induction by right ventricular pacing/extrastimuli in eccentric rather than concentric retrograde atrial activation. A shorter antegrade fast functional refractory period of the AV node was demonstrated in the atypical eccentric group as compared to the atypical concentric group. CONCLUSION: This study demonstrated the different electrophysiologic characteristics between the AVNRT patients with eccentric and concentric retrograde atrial activation. Successful ablation sites were similar to the standard RA ablation sites in patients with retrograde eccentric conduction.

Adolescent↗
PubMed2006

Anatomic characteristics of the left atrial isthmus in patients with atrial fibrillation: lessons from computed tomographic images.

INTRODUCTION: Left atrial (LA) isthmus ablation was reported to improve the success rate of catheter ablation of paroxysmal atrial fibrillation (AF). LA isthmus ablation could also cure a subset of LA flutter. Therefore, understanding the anatomy of the LA isthmus is important for performing the ablation effectively. METHODS AND RESULTS: Group I included 45 patients (40 male, mean age = 50 +/- 13 years) with paroxysmal AF who underwent catheter ablation. Group II included 45 patients (37 male, mean age = 54 +/- 10 years) without a history of AF. They underwent a 16-slice multidetector computed tomography (MDCT) scan to delineate the LA structures before the ablation procedure. The average length of the LA isthmus was longer in group I than in group II (lateral isthmus: 3.30 +/- 0.68 vs 2.71 +/- 0.60 cm, P < 0.001; medial isthmus: 5.12 +/- 0.94 vs 4.45 +/- 0.63 cm, P < 0.001), and morphological patterns of lateral and medial isthmus were similar between groups. In addition, the average depth of lateral isthmus was similar between groups (0.62 +/- 0.32 vs 0.55 +/- 0.33 cm, P = 0.41), but the average depth of medial isthmus was larger in group I than in group II (0.60 +/- 0.32 vs 0.44 +/- 0.25 cm, P = 0.01). The medial isthmus had more ridges, as compared to the lateral isthmus (13% vs 0%, P = 0.026). Furthermore, the distances between esophagus and lateral isthmus were longer in group I than in group II (at the middle of isthmus and mitral annulus level: 21.0 +/- 4.8 vs 18.4 +/- 6.0 mm, P < 0.001; and 37.1 +/- 5.7 vs 29.6 +/- 8.1 mm, P < 0.001, respectively). CONCLUSION: The LA isthmus was longer in the AF patients. The morphology of the isthmus was variable. Compared with the lateral isthmus, the medial isthmus was longer and had more ridges. A peculiar configuration of the isthmus provided by CT images could influence the ablation strategy.

Anthropometry↗
PubMed2006

Morphological changes of the left atrial appendage after catheter ablation of atrial fibrillation.

INTRODUCTION: The left atrial appendage (LAA) has been proven to be the most important site of thrombus formation in patients with atrial fibrillation (AF). However, the information regarding the morphometric alteration of the LAA related to the outcome of AF ablation is still lacking. Thus, we evaluated the long-term changes of the LAA morphology in patients undergoing catheter ablation of AF using magnetic resonance angiography (MRA). METHODS AND RESULTS: Group 1 included 15 controls without any AF history. Group 2 included 40 patients with drug-refractory paroxysmal AF. They were divided into two subgroups: group 2a included 30 patients without AF recurrence after pulmonary vein (PV) ablation. Group 2b included 10 patients with late recurrence of AF. The LAA morphology before and after (20 +/- 11 months) ablation was evaluated by three-dimensional MRA. The group 2 patients had a larger baseline LAA size (including the LAA orifice, neck, and length) and less eccentric LAA orifice and neck. After the AF ablation, there was a significant reduction in the LAA size in the group 2a patients, and the morphology of the LAA neck became more eccentric during the follow-up period. In group 2b, the LAA size increased and no significant change in the eccentricity of the orifice and neck could be noted. CONCLUSIONS: The morphometric remodeling of the LAA in the AF patients could be reversed after a successful ablation of the AF. Progressive dilation of the LAA was noted in the patients with AF recurrence. These structural changes in the LAA may play a role in reducing the potential risk of cerebrovascular accidents.

Atrial Appendage↗
PubMed2006

Cardiovascular imaging in the management of atrial fibrillation.

Atrial fibrillation (AF) is he most commonly encountered arrhythmia in clinical practice, with an overall prevalence of 0.4% in the general population. Recent advances in technology and in the understanding of the pathophysiology of AF have led to more definitive and potentially curative therapeutic approaches. Echocardiography has a well-established role in the assessment of cardiac structure and function and risk stratification, and has become an essential part of the guidelines for management of AF. The development of intracardiac echocardiography has led to real-time guidance of percutaneous interventions, including radiofrequency ablation and left atrial appendage closure procedures for patients with AF. Other imaging modalities, including computed tomography and magnetic resonance angiography, have allowed for more accurate measurement and better understanding of the cardiac anatomy. We review the impact of various imaging modalities in the evaluation and management of AF.

Atrial Fibrillation↗
PubMed2006

The electroanatomic characteristics of the cavotricuspid isthmus: implications for the catheter ablation of atrial flutter.

INTRODUCTION: Radiofrequency ablation (RFA) of typical AFL is sometimes difficult because of the poor electroanatomic approach to the cavotricuspid isthmus (CTI). The aim of this study was to correlate the anatomy of the CTI between contact mapping (NavX) and right atrial angiography (RAG), and to investigate the impact of the electroanatomic characteristics of the CTI on the RFA of typical atrial flutter (AFL). METHODS: One hundred patients with typical AFL undergoing RFA were studied. The image-guided group consisted of 50 consecutive patients with the guidance of NavX. NavX geometry and RAG were performed to investigate the morphology of the CTI. The bipolar voltages of the CTI were collected during sinus rhythm by a NavX. The control group consisted of 50 consecutive patients with the guidance of conventional fluoroscopy. RESULTS: There was a good correlation between the angiography and NavX for the anatomy of the CTI. The pouch type had a longer length of CTI than the flat type (33.4 +/- 5.0 vs 22.6 +/- 8.4 mm, P < 0.0001) and deeper depth than the concave type (6.5 +/- 2.2 vs 3.7 +/- 0.8 mm, P < 0.0001) on the angiography. The pouch-type CTI had a longer ablation time and larger pulses of RFA than the other two types. The control group had a longer ablation time, fluoroscopy time, and larger pulses of RFA than image-guided group. CONCLUSIONS: The 3-D mapping system provided a good reconstruction of CTI, which may help in the RFA in patients with a complex anatomy of the CTI.

Adult↗
PubMed2006

Noncontact three-dimensional mapping guides catheter ablation of difficult atrioventricular nodal reentrant tachycardia.

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia in adulthood. Although selective ablation of the slow AV nodal pathway can cure AVNRT, accidental AV block may occur. The details on the electrophysiologic characteristics, quantitative data on the voltage inside Koch's triangle, and the use of three-dimensional noncontact mapping to facilitate the catheter ablation of AVNRT associated with a high-risk for AV block or other arrhythmias have been limited. METHODS AND RESULTS: Nine patients (M/F=5/4, 34+/-23 years, range 17-76) with clinically documented AVNRT were included. All patients had undergone previous sessions for slow AV nodal pathway ablation but they had failed, because of repetitive episodes of complete AV block during the RF energy applications. Further, one patient had a complex anatomy and 4 patients were associated with other tachycardias, respectively. The electrophysiologic studies revealed that 4 patients had the slow-fast, 4 the slow-intermediate and one the fast-intermediate form of AVNRT. Noncontact mapping demonstrated two types of antegrade AV nodal conduction, markedly differing sites of the earliest atrial activation during retrograde VA conduction, and a lower range of voltage within Koch's triangle. The lowest border of the retrograde conduction region was defined on the map, and the application of the RF energy was delivered below that border to prevent the occurrence of AV block. The distance between the successful ablation lesions and the lowest border of the retrograde conduction region was significantly shorter in the patients with the slow-intermediate form of AVNRT than in those with the slow-fast form (5.5+/-3.4 vs. 15+/-7.6 mm; p<0.05). After the ablation procedure, either rapid pacing or extrastimulation could not induce any tachycardia, and there was no recurrence during the follow-up (10.3+/-5.4, 2 to 22 months). CONCLUSIONS: Noncontact mapping could effectively demonstrate the antegrade and retrograde atrionodal conduction patterns, electrophysiologic characteristics of Koch's triangle, and guide the successful catheter ablation in difficult AVNRT cases.

Adolescent↗
PubMed2006

Substrate mapping to detect abnormal atrial endocardium with slow conduction in patients with atypical right atrial flutter.

OBJECTIVES: The purpose of this study was to investigate the relationship between the abnormal substrate and peak negative voltage (PNV) in the right atrium (RA) with atypical flutter. BACKGROUND: The impact of a local abnormally low voltage electrogram on the local activation pattern and velocity of atrial flutter (AFL) remains unclear. METHODS: Twelve patients with clinically documented AFL were included to undergo noncontact mapping of the RA. The atrial substrate was characterized by the: 1) activation mapping; 2) high-density voltage mapping; and 3) conduction velocity along the flutter re-entrant circuit. The normalized PNV (i.e., the relative ratio to the maximal PNV) in each virtual electrode recording was used to produce the voltage maps of the entire chamber. The protected isthmus was bordered by low voltage zones. RESULTS: Atypical AFL of the RA was induced by atrial pacing in 12 patients, including 10 upper loop re-entry and 2 RA free wall re-entry flutter. These protected isthmuses were located near the crista terminalis. The mean width of the protected isthmus was 1.7 +/- 0.3 cm and mean voltage at the isthmus was -0.91 +/- 0.39 mV. The conduction velocities within these paths were significantly slower than outside the path (0.30 +/- 0.18 m/s vs. 1.14 +/- 0.41 m/s, respectively; p = 0.004). The ratiometric PNV of 37.6% of the maximal PNV had the best cut-off value to predict slow conduction, with a high sensitivity (92.3%) and specificity (85.7%). CONCLUSIONS: Characterization of the RA substrate in terms of the unipolar PNV is an effective predictor of the slow conduction path within the critical isthmus of the re-entrant circuit.

Adult↗
PubMed2006

Remodeling of myocardial sleeve and gap junctions in canine superior vena cava after rapid pacing.

OBJECTIVE: We studied the response of the superior vena cava (SVC) myocardial sleeve to atrial fibrillation (AF). METHODS AND RESULTS: We examined adult male dogs without pacing (N=6) and after rapid atrial pacing (600 bpm) for 2 weeks (P2w; N=5) and 6-8 weeks (P6-8w; N=5). After pacing, the sleeve was increased in thickness (non-paced vs. either paced group, both P<0.05). This was associated with an increase in proliferative activity, which was higher in the P2w than the P6-8w animals (P<0.05). In addition, collagen content increased, and the component cardiomyocytes become more unevenly oriented and shorter and narrower in shape (non-paced vs. either paced group, both P<0.05). Pacing had different effects on connexin40 (Cx40) and Cx43 gap junctions. There was a 98% increase in Cx43 signal in P2w, and a 74% increase in P6-8w animals (non-paced vs. each paced group, both P<0.05). In contrast, Cx40 signal decreased 47% in P2w but increased 44% in P6-8w animals (non-paced vs. each paced group, both P<0.05). CONCLUSIONS: Rapid atrial pacing results in a specific pattern of remodeling of the canine SVC sleeve, including changes in size and shape, spatial orientation, and gap junction expression profile of the component cardiomyocytes. These changes may co-operatively affect the electrical properties and contribute to the formation and maintenance of the arrhythmogenic substrate of AF.

Animals↗
PubMed2006

Frequency analysis in different types of paroxysmal atrial fibrillation.

OBJECTIVES: This study sought to investigate the regional frequency distribution from multiple bi-atrial sites in different types of paroxysmal atrial fibrillation (AF). BACKGROUND: A previous study showed a left atrium (LA) to right atrium (RA) frequency gradient in patients with paroxysmal AF. METHODS: Forty-four patients (age = 60 +/- 16, male patients = 27) with paroxysmal AF originating from the pulmonary veins (PVs) (n = 31) or superior vena cava (SVC) (n = 13) were included. Frequency analysis was performed on the intracardiac electrograms (7 s, 1 kHz/channel) recorded from PV, posterior LA, coronary sinus (CS), posterolateral RA, and SVC. The largest peak frequency was identified as the dominant frequency (DF). RESULTS: In the PV-AF patients, there was a frequency gradient from the PV ostium to the LA, RA, and SVC (8.5 +/- 3.3 Hz vs. 5.9 +/- 1.1 Hz vs. 5.2 +/- 0.85 Hz vs. 5.5 +/- 0.48 Hz, respectively, p < 0.001). The highest DFs were mostly located at the arrhythmogenic PV ostium (58%). The DFs of the arrhythmogenic PV and PV ostium were significantly higher than those of the non-arrhythmogenic PVs and PV ostia (p < 0.05). In the SVC-AF patients, there was a frequency gradient from the SVC to the RA, LA, and PV (8.0 +/- 2.4 Hz vs. 5.9 +/- 1.1 Hz vs. 5.9 +/- 0.7 Hz vs. 5.8 +/- 0.7 Hz, respectively, p = 0.001). The highest DFs were mostly located inside the SVC (77%) instead of the SVC ostium (as compared with PV-AF patients, p = 0.035). CONCLUSIONS: The location of the highest DF depended on the arrhythmogenic PV or SVC. A frequency gradient was present between the arrhythmogenic thoracic vein and atrium in all patients.

Atrial Fibrillation↗
PubMed2006

Effects of a Na+/Ca2+ exchanger inhibitor on pulmonary vein electrical activity and ouabain-induced arrhythmogenicity.

OBJECTIVE: Pulmonary veins (PVs) are the most important focus for generation of atrial fibrillation. The Na(+)/Ca(2+) exchange (NCX) current is important in PV electrical activity and cardiac glycosides-induced arrhythmias. The purpose of this study was to investigate whether KB-R7943, a NCX current blocker with preferential inhibition of the Ca(2+) influx, may alter PV electrophysiological characteristics and reduce glycoside-induced arrhythmogenicity. METHODS: Conventional microelectrodes were used to record the effects of KB-R7943 on action potentials and contractility in isolated rabbit PV tissue specimens with and without administration of ouabain. The ionic currents and intracellular calcium were studied in isolated single cardiomyocytes before and after KB-R7943 by the whole-cell patch clamp and indo-1 fluorimetric ratio techniques. RESULTS: KB-R7943 (0, 3, 10, 30 microM) concentration-dependently prolonged APD(50) and APD(90) and decreased the PV firing rates (2.3 +/- 1.2 Hz, 2.1 +/- 1.2 Hz, 1.9 +/- 0.9 Hz, 1.7 +/- 1.1 Hz, n = 7, p < 0.05) and incidences of delayed afterdepolarizations (DADs). KB-R7943 (3, 30 microM) decreased transient inward currents, Ca(2+) transient and sarcoplasmic reticulum Ca(2+) content. Ouabain (0, 0.1, 1 microM) concentration-dependently increased the PV firing rates and DADs in PVs with spontaneous activity (n = 7) and induced nonsustained spontaneous activity (1 microM) in the PVs without spontaneous activity (n = 14). However, in the presence of KB-R7943 (30 microM), ouabain (1 microM) did not increase the PV firing rates or induce spontaneous activity in the PVs without spontaneous activity (n = 7). CONCLUSIONS: KB-R7943 reduces the PV arrhythmogenic activity and prevents the ouabain-induced arrhythmogenicity. Our findings support the role of the NCX current in the PV electrical activity.

Action Potentials↗
PubMed2006

The electrophysiologic characteristics in patients with only ventricular-pacing inducible slow-fast form atrioventricular nodal reentrant tachycardia.

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) can be usually induced by atrial pacing or extrastimulation. However, it is less commonly induced only by ventricular pacing or extrastimulation. OBJECTIVE: The purpose of this retrospective study was to investigate the electrophysiologic characteristics in patients with slow-fast form AVNRT that could be induced only by ventricular pacing or extrastimulation. METHODS: The total population was 1497 patients associated with AVNRT. There were 1373 (91.7%) patients who had slow-fast form AVNRT included in our study. Group 1 (n = 45) could be induced only by ventricular pacing or extrastimulation, and Group 2 (n = 1328) could be induced by only atrial stimulation or both atrial and ventricular stimulation. The electrophysiologic characteristics of the group 1 and group 2 patients were compared. RESULTS: Group 1 patients had a significantly lower incidence of both antegrade and retrograde dual AV nodal pathways. The pacing cycle length (CL) of the antegrade 1:1 fast pathway (FP) and antegrade ERP of the FP were both significantly shorter in Group 1 patients. Mean antegrade FRP of the fast and slow pathways were significantly shorter in Group 1 patients. The differences of pacing CL of 1:1 antegrade conduction, antegrade ERP and FRP were much longer in Group 2 patients. CONCLUSION: This study demonstrated the patients with slow-fast form AVNRT that could be induced only by ventricular stimulation had a lower incidence of dual AV nodal pathways and the different electrophysiologic characteristics (shorter pacing CL of the antegrade 1:1 FP, antegrade ERP of the FP and the differences of pacing CL of 1:1 antegrade conduction, antegrade ERP and FRP) from the other patients. The specific electrophysiologic characteristics in such patients could be the reason that could be induced only by ventricular stimulation.

Adolescent↗
PubMed2006

Coronary sinus morphology in different types of supraventricular tachycardias.

BACKGROUND: Atrioventricular nodal reentry tachycardia (AVNRT) is based on the concept of dual AV node pathways that are functionally and anatomically distinct. The bigger coronary sinus ostium (CSO) in patients with AVNRT compared to other supraventricular tachycardias (SVTs) may produce separation of atrial inputs into the AV node or create anisotropic conduction, thus giving rise to a different AV nodal physiology. Previous studies measuring the size of the CSO using CS angiography between patients with AVNRT and other SVTs showed conflicting results. Besides, no previous studies have compared the CS morphology of the different forms of AVNRT. OBJECTIVES: This study compares the size and morphology of the CS among patients with typical AVNRT, atypical AVNRT and accessory pathways mediated reentrant tachycardia (AVRT). METHODS: Ninety-six patients with clinically documented SVTs were divided into three groups. The diameter of the CS was measured in LAO projection during end ventricular systole (by choosing the last ventricular inward motion). The CSO as well as 5, 10 and 15 mm inside the CS were measured. CS morphology is defined as either wind-sock shape or tubular shape. RESULTS: The size of the CS ostium was 13.58 +/- 3.98, 15.93 +/- 4.86 and 12.50 +/- 2.83 mm for the atypical AVNRT, typical AVNRT and AVRT, respectively (p = 0.03). There was significant difference in the size of the CS from the ostium until 15 mm into the CS between 1) typical AVNRT and AVRT, 2) typical AVNRT and atypical AVNRT. Typical and atypical AVNRT patients had more windsock morphology CS (13/32, 40.6% and 10/32, 31.2%) compared to AVRT which had only one (1/32, 3.1%) windsock morphology (p = 0.002). CONCLUSION: The easier CS cannulation in patients with typical AVNRT could be due to a bigger CS size and to a more windsock morphology. The CS size and morphology may be a very important substrate of tachycardia in patients with AVNRT.

Adult↗
PubMed2006

Angiotensin II and angiotensin II receptor blocker modulate the arrhythmogenic activity of pulmonary veins.

Angiotensin II receptor blockers (AIIRBs) have been shown to prevent atrial fibrillation. The pulmonary veins (PVs) are the most important focus for the generation of atrial fibrillation. The aim of this study was to evaluate whether angiotensin II or AIIRB may change the arrhythmogenic activity of the PVs. Conventional microelectrodes and whole-cell patch clamps were used to investigate the action potentials (APs) and ionic currents in isolated rabbit PV tissue and single cardiomyocytes before and after administering angiotensin II or losartan (AIIRB). In the tissue preparations, angiotensin II induced delayed after-depolarizations (1, 10, and 100 nM) and accelerated the automatic rhythm (10 and 100 nM). Angiotensin II (100 nM) prolonged the AP duration and increased the contractile force (10 and 100 nM). Losartan (1 and 10 microM) inhibited the automatic rhythm. Losartan (10 microM) prolonged the AP duration and reduced the contractile force (1 and 10 microM). Angiotensin II reduced the transient outward potassium current (I(to)) but increased the L-type calcium, delayed rectifier potassium (I(K)), transient inward (I(ti)), pacemaker, and Na(+)-Ca(2+) exchanger (NCX) currents in the PV cardiomyocytes. Losartan decreased the I(to), I(K), I(ti), and NCX currents. In conclusion, angiotensin II and AIIRB modulate the PV electrical activity, which may play a role in the pathophysiology of atrial fibrillation.

Angiotensin II↗
PubMed2006

Electrophysiologic characteristics and radiofrequency catheter ablation in children with Wolff-Parkinson-White syndrome.

BACKGROUND: The majority of cardiac arrhythmias in children are supraventricular tachycardia, which is mainly related to an accessory pathway (AP)-mediated reentry mechanism. The investigation for Wolff-Parkinson-White (WPW) syndrome in adults is numerous, but there is only limited information for children. This study was designed to evaluate the specific electrophysiologic characteristics and the outcome of radiofrequency (RF) catheter ablation in children with WPW syndrome. METHODS: From December 1989 to August 2005, a total of 142 children and 1,219 adults with atrioventricular reentrant tachycardia (AVRT) who underwent ablation at our institution were included. We compared the clinical and electrophysiologic characteristics between children and adults with WPW syndrome. RESULTS: The incidence of intermittent WPW syndrome was higher in children (7% vs 3%, P=0.025). There was a higher occurrence of rapid atrial pacing needed to induce tachycardia in children (67% vs 53%, P=0.02). However, atrial fibrillation (AF) occurred more commonly in adult patients (28% vs 16%, P=0.003). The pediatric patients had a higher incidence of multiple pathways (5% vs 1%, P<0.001). Both the onset and duration of symptoms were significantly shorter in the pediatric patients. The antegrade 1:1 AP conduction pacing cycle length (CL) and antegrade AP effective refractory period (ERP) in children were much shorter than those in adults with manifest WPW syndrome. Furthermore, the retrograde 1:1 AP conduction pacing CL and retrograde AP ERP in children were also shorter than those in adults. The antegrade 1:1 atrioventricular (AV) node conduction pacing CL, AV nodal ERP, and the CL of the tachycardia were all shorter in the pediatric patients. CONCLUSION: This study demonstrated the difference in the electrophysiologic characteristics of APs and the AV node between pediatric and adult patients. RF catheter ablation was a safe and effective method to manage children with WPW syndrome.

Adolescent↗
PubMed2006

The different ablation effects on atrioventricular nodal reentrant tachycardia in children with and without dual nodal pathways.

BACKGROUND: Previous studies in adults have shown a significant shortening of the fast pathway effective refractory period (ERP) after successful slow pathway ablation. However, information on atrioventricular nodal reentrant tachycardia (AVNRT) in children is limited. The purpose of this retrospective study was to investigate the different effects of radiofrequency (RF) catheter ablation in pediatric AVNRT patients between those with and without dual atrioventricular (AV) nodal pathways. METHODS: From January 1992 to August 2004, a total 67 pediatric patients with AVNRT underwent an electrophysiologic study and RF catheter ablation at our institution. We compared the electrophysiologic characteristics between those obtained before and after ablation in the children with AVNRT with and without dual AV nodal pathways. RESULTS: Dual AV nodal pathways were found in 37 (55%) of 67 children, including 36 (54%) with antegrade and 10 (15%) with retrograde dual AV nodal pathways. The antegrade and retrograde fast pathway ERPs in children with dual AV nodal pathways were both longer than the antegrade and retrograde ERPs in children without dual AV nodal pathways (300 +/- 68 vs 264 +/- 58 ms, P = 0.004; 415 +/- 70 vs 250 +/- 45 ms, P < 0.001) before ablation. In children with antegrade dual AV nodal pathways, the antegrade fast pathway ERP decreased from 300 +/- 68 ms to 258 +/- 62 ms (P = 0.008). The retrograde fast pathway ERP also decreased after successful ablation in the children with retrograde dual AV nodal pathways (415 +/- 70 vs. 358 +/- 72 ms, P = 0.026). CONCLUSION: The dual AV nodal physiology could not be commonly demonstrated in pediatric patients with inducible AVNRT. After a successful slow pathway ablation, the fast pathway ERP shortened significantly in the children with dual AV nodal pathways.

Adolescent↗