Transient complete atrioventricular block during radiofrequency ablation of slow pathway for atrioventricular nodal reentrant tachycardia.
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Atrioventricular Node↗
Biomedical subjects
K C Ueng
Publications and source records attributed to K C Ueng.
Longitudinal clinical and electrophysiological assessment of patients with symptomatic Wolff-Parkinson-White syndrome and atrioventricular node reentrant tachycardia.
BACKGROUND: Functional changes of the accessory AV pathways and dual AV node pathways are very important for patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia who refuse to receive long-term medication or radiofrequency catheter ablation. However, no studies of serial clinical and electrophysiological characteristics in these patients have been performed. METHODS AND RESULTS: One hundred thirteen patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia were included in this study. The first and second follow-up electrophysiological studies were performed in years 5 and 10 after the baseline study, respectively. Conduction properties of the accessory pathways became poor over time. After a mean follow-up period of 9 +/- 1 years, antegrade ventricular preexcitation and retrograde accessory pathway conduction disappeared in 22.5% and 7.8% (P < .01), respectively; dual AV node pathway physiology persisted and retrograde fast pathway disappeared in 10.8% of the patients. Baseline conduction properties of the antegrade and retrograde accessory pathways and the retrograde fast pathway independently predicted late loss of conduction. Spontaneous disappearance of the original tachyarrhythmias occurred in 10.3% of all patients, and newly developed tachyarrhythmias in 15.2%. The incidence (38.5%) of newly developed atrial fibrillation was significantly higher in patients with manifest accessory pathways. Furthermore, symptom scores and attack frequency increased significantly over time in the patients with accessory pathways and AV node reentrant tachycardia. CONCLUSIONS: Disappearance of the original tachycardia and changing patterns of tachycardia, also with an increase in symptom scores and attack frequency, suggested that a detailed evaluation of these events is important and early intervention with radiofrequency ablation would be helpful.
Adolescent↗
Electrophysiological mechanisms in successful radiofrequency catheter modification of atrioventricular junction for patients with medically refractory paroxysmal atrial fibrillation.
BACKGROUND: Mechanisms and changes of electrophysiological (EP) characteristics in successful radiofrequency (RF) modification of right midseptal and posteroseptal areas for controlling rapid ventricular response to atrial fibrillation (Af) are not clear. METHODS AND RESULTS: We studied 50 patients with medically refractory paroxysmal Af. Group 1 consisted of 40 patients without dual atrioventricular (AV) node physiology with modification sites located in the mid/posteroseptal area. Of the 40 patients, 36 had successful modification (follow-up of 14 +/- 8 months), and 3 had AV block. Late follow-up electrophysiological study (98 +/- 10 days) showed pattern 1 (67%) with prolongation of AV node effective refractory period (ERP, > or =40 milliseconds) and Wenckebach block cycle length (WBCL, > or =40 milliseconds); pattern 2 (22%) with prolongation of AH interval (> or =20 milliseconds), ERP, and WBCL; and pattern 3 (11%) without any change in AV node conduction parameter. Change in ventricular rate negatively correlated with change of WBCL in patterns 1 (r=-.691, P=.019) and 2 (r=-.90, P=.01). Group 2 consisted of 10 patients with dual AV node pathway; elimination of slow pathway property was performed. Late follow-up electrophysiological study (92+/-7 days) showed that change in ventricular rate negatively correlated with change in AV node ERP (r=-.926, P=.0001) and WBCL (r=-.969, P=.0001). Four patients without significant modification effect had success after RF energy was delivered to higher levels (follow-up, 15+/-7 months). CONCLUSIONS: RF modification of right mid/posteroseptal area is feasible in 92% of patients with paroxysmal Af. Mechanisms of successful modification might be elimination of posterior input and/or partial injury of the compact node. Furthermore, simple elimination of slow pathway might be inadequate for control of ventricular rate in patients with little difference in conduction properties between fast and slow pathways.
Adult↗
Radiofrequency catheter ablation of common atrial flutter: comparison of electrophysiologically guided focal ablation technique and linear ablation technique.
OBJECTIVES: The purpose of this study was to study electrophysiologic characteristics and compare the electrophysiologically guided focal ablation technique and linear ablation technique in patients with common atrial flutter in a prospective randomized fashion. Background. Catheter ablation of the common atrial flutter circuit can be performed with different techniques. To date, these two techniques have not been compared prospectively in a randomized study. METHODS: Sixty patients with drug-refractory common atrial flutter were randomly assigned to undergo radiofrequency catheter ablation performed with the electrophysiologically guided focal ablation (Group I) or linear ablation technique (Group II). In Group I, radiofrequency energy was delivered to the site characterized by concealed entrainment with a short stimulus-P wave interval (<40 ms) and a postpacing interval equal to the atrial flutter cycle length. In Group II, continuous migratory application of radiofrequency energy was used to create two linear lesions in or around the inferior vena cava-tricuspid ring isthmus. Serial 24-h ambulatory electrocardiographic (Holter) and follow-up electrophysiologic studies were performed to assess recurrence of tachycardia and possible atrial arrhythmogenic effects. RESULTS: Successful elimination of the flutter circuit was achieved in 28 of 30 patients in Group I and 29 of 30 patients in Group II. More atrial premature beats and episodes of short run atrial tachyarrhythmias in the early period (within 2 weeks) after ablation were found in Group II. Recurrence rate (2 of 28 vs. 3 of 29) and incidence of new sustained atrial tachyarrhythmias (3 of 28 vs. 3 of 29) was similar in the two groups. Occurrence of recurrent atrial flutter and new sustained atrial tachyarrhythmias was related to associated cardiovascular disease and atrial enlargement in both groups. However, in Group II, the procedure time (104 +/- 17 vs. 181 +/- 29 min, p<0.01) were significantly shorter than those in Group I. CONCLUSIONS: Radiofrequency ablation of the common atrial flutter circuit was safe and effective with either the electrophysiologically guided focal ablation or linear ablation technique. However, the linear ablation technique was time-saving.
Aged↗
Prediction of successful ablation site of concealed posteroseptal accessory pathways by a novel algorithm using baseline electrophysiological parameters: implication for an abbreviated ablation procedure.
BACKGROUND: Radiofrequency catheter ablation of concealed posteroseptal accessory pathways (APS) has been a relatively difficult task for electrophysiologists. Without a detailed mapping procedure, the left versus the right posteroseptal AP could not be distinguished. We investigated the electrophysiological characteristics of concealed posteroseptal APs and defined criteria from baseline parameters to predict the successful ablation site. Validity of the criteria was prospectively verified. METHODS AND RESULTS: Eighty-nine consecutive patients with a single concealed posteroseptal AP underwent successful radiofrequency catheter ablation. Of the initial 48 patients (group 1), the right posteroseptal area was first mapped. If no ideal electrogram could be obtained, or after several ineffective radiofrequency pulses, the left posteroseptal area was then mapped. Special attention was paid to the stability of the coronary sinus catheter with the most proximal electrode straddling the ostium, verified by coronary sinus venography, in all patients. Six patients (12.5%) had the earliest retrograde atrial activation at the middle electrode of the coronary sinus catheter, and successful ablation could only be achieved at the left posteroseptal area. For patients who presented with the earliest atrial activation at the proximal electrode, the presence of long RP' tachycardia suggested a right endocardial approach, while the delta VA (defined as the difference in the VA intervals between that recorded at the His bundle catheter and that at one of the electrode groups recording the earlier atrial activation) >-25 ms during tachycardia suggested a left endocardial approach. The subsequent 41 patients (group 2) were randomized into two subgroups. The initial mapping site was guided by the algorithm in group 2B, while it was not in group 2A. The successful ablation site could be predicted accurately in 18 (90%) of the 20 patients in group 2B. The radiofrequency pulses, ablation time, and fluoroscopic time were markedly reduced in Group 2B, mainly because of the omission of unnecessary mapping procedure in the right posteroseptal area in patients with "left atrio-left ventricular" fibers. CONCLUSIONS: By the algorithm based on baseline electrophysiological parameters, the successful ablation site could be accurately predicted in a majority of patients with concealed posteroseptal APs. Radiofrequency pulses, ablation time, and fluoroscopic time were markedly reduced.
Adult↗
Complications of diagnostic electrophysiologic studies and radiofrequency catheter ablation in patients with tachyarrhythmias: an eight-year survey of 3,966 consecutive procedures in a tertiary referral center.
Predictors and comparisons of complications in patients with electrophysiologic study or radiofrequency ablation have not been assessed in previous published reports. The purpose of this study was to prospectively evaluate the procedure-specific complications and investigate the possible causes and predictors of complications in electrophysiologic study and radiofrequency ablation. Data of diagnostic electrophysiologic studies and radiofrequency ablation were prospective, and represented a consecutive series of 2,593 patients with 3,966 procedures. The present study showed that a significantly higher complication rate occurred in radiofrequency ablation than in electrophysiologic study (3.1% vs. 1.1%, respectively, p = 0.00002) and a significantly higher complication rate occurred in elderly than in young patients with electrophysiologic study (2.2% vs 0.5%, p = 0.0002) or radiofrequency ablation (6.1% vs 2.0%, p = 0.00015). Multiple logistic analysis found that older age (p < 0.01) and systemic disease in elderly patients (p < 0.01) were the independent predictors of complications in both procedures. Furthermore, there was no temporal trend in the incidence of complication. We conclude that the incidence of complication was higher in radiofrequency ablation, and elderly patients had a higher incidence of complications in both electrophysiologic study and radiofrequency ablation; these procedures, when performed by experienced personnel in an appropriately staffed and equipped laboratory, can be undertaken with an acceptable risk.
Adult↗
Electrophysiologic characteristics and radiofrequency catheter ablation in patients with multiple atrioventricular nodal reentry tachycardias.
Information about the mechanism and radiofrequency catheter ablation of multiple atrioventricular (AV) nodal reentry tachycardias is limited. Among the 550 consecutive patients with AV nodal reentry tachycardia, 36 with multiple forms of AV nodal reentry tachycardia were included in this study. Electrophysiologic characteristics, as well as the efficacy and safety of radiofrequency ablation, were evaluated. Results showed that anterograde dual pathways were seen in 32 patients and triple pathways in 2, and retrograde dual pathways were seen in 23 patients and triple pathways in 11. Twenty-two patients had 2 types, 7 had 3 types, 5 had 4 types, and 2 had 5 types of AV nodal reentry tachycardia and echoes. After delivering radiofrequency energy to the target sites, 32 patients had no induction of AV nodal reentry tachycardia and only 4 had induction of 1 echo. Furthermore, 22 patients (61%) had simultaneous elimination or modification of the slow and/or intermediate pathways in the anterograde and retrograde direction. During the follow-up period of 19 +/- 14 months, 2 patients had recurrence of tachycardia. Thus, multiple anterograde and retrograde AV nodal pathways were present in the human AV node and they constituted the substrates of reentry circuits. Radiofrequency catheter ablation was safe and effective in eliminating the slow and intermediate pathways for maintenance of multiple AV nodal reentry tachycardias.
Adult↗
Efficiency of heating during radiofrequency catheter ablation of accessory atrioventricular pathways.
Adequate heating with myocardial thermal injury is necessary for successful ablation. This study was designed to examine the relationship between power, temperature, and efficiency of heating during radiofrequency catheter ablation of accessory pathways in 76 patients. During each application of radiofrequency energy, temperature was continually monitored by use of an ablation catheter with a thermistor embedded in the tip of the distal electrode. The efficiency of heating varied by location, with the greatest efficiency of heating for posteroseptal energy applications (2.7 +/- 2.3 degrees C/W), which were significantly greater than for left-sided (2.1 +/- 1.9 degrees C/W, P < 0.01) or right-sided (1.0 +/- 1.1 degrees C/W, P < 0.01) applications. For patients with left free wall and posteroseptal pathways, the temperature, radiofrequency power, time to peak temperature and efficiency of heating were similar between the successful and unsuccessful pulses. However, the mean temperature (53.5 +/- 4.5 vs. 45.1 +/- 5.1 degrees C, P < 0.01) and radiofrequency power (49.6 +/- 5.2 vs. 40.3 +/- 10.2 watt, P < 0.05) differed significantly between the successful and unsuccessful ablation pulses in patients with right free wall pathways. To achieve greater efficiency of heating and higher temperature, it is reasonable to use higher power outputs (40-50 W) in radiofrequency ablation of right free wall pathways, whereas less power outputs (30-40 W) are likely to produce adequate heating of posteroseptal and left free wall pathways, and minimize the risk of impedance rise and coagulum formation.
Adolescent↗
Multiple anterograde atrioventricular node pathways in patients with atrioventricular node reentrant tachycardia.
OBJECTIVES: This study sought to investigate electrophysiologic characteristics and possible anatomic sites of multiple anterograde slow atrioventricular (AV) node pathways and to compare these findings with those in dual anterograde AV node pathways. BACKGROUND: Although multiple anterograde AV node pathways have been demonstrated by the presence of multiple discontinuities in the AV node conduction curve, the role of these pathways in the initiation and maintenance of AV node reentrant tachycardia (AVNRT) is still unclear, and possible anatomic sites of these pathways have not been reported. METHODS: This study included 500 consecutive patients with AVNRT who underwent electrophysiologic study and radiofrequency ablation. Twenty-six patients (5.2%) with triple or more anterograde AV node pathways were designated as Group I (16 female, 10 male, mean age 48 +/- 14 years), and the other 474 patients (including 451 with and 23 without dual anterograde AV node pathways) were designated as Group II (257 female, 217 male; mean age 52 +/- 16 years). RESULTS: Of the 21 patients with triple anterograde AV node pathways, AVNRT was initiated through the first slow pathway only in 3, through the second slow pathway only in 8 and through the two slow pathways in 9. Of the five patients with quadruple anterograde AV node pathways, AVNRT was initiated through all three anterograde slow pathways in three and through the two slower pathways (the second and third slow pathways) in two. After radiofrequency catheter ablation, no patient had inducible AVNRT. Eleven patients (42.3%) in Group I had multiple anterograde slow pathways eliminated simultaneously at a single ablation site. Eight patients (30.7%) had these slow pathways eliminated at different ablation sites; the slow pathways with a longer conduction time were ablated more posteriorly in the Koch's triangle than those with a shorter conduction time. The remaining seven patients (27%) had a residual slow pathway after delivery of radiofrequency energy at a single or different ablation sites. The patients in Group I had a longer tachycardia cycle length, poorer retrograde conduction properties and a higher incidence of multiple types of AVNRT than those in Group II. CONCLUSIONS: Multiple anterograde AV node pathways are not rare in patients with AVNRT. However, not all of the anterograde slow pathways were involved in the initiation and maintenance of tachycardia. Radiofrequency catheter ablation was safe and effective in eliminating critical slow pathways to cure AVNRT.
Adult↗
Electrophysiologic characteristics, electropharmacologic responses and radiofrequency ablation in patients with decremental accessory pathway.
OBJECTIVES: This study sought to characterize the functional properties of decremental accessory atrioventricular (AV) pathways and to investigate their pharmacologic responses. BACKGROUND: Although decremental AV pathways associated with incessant reciprocating tachycardia have been studied extensively, information about the electrophysiologic characteristics and pharmacologic responses of anterograde and retrograde decremental AV pathways is limited. METHODS: Of 759 consecutive patients with accessory pathway-mediated tachyarrhythmia, 74 with decremental AV pathways were investigated (mean age 43 +/- 18 years). After baseline electrophysiologic study, the serial drugs adenosine, verapamil and procainamide were tested during atrial and ventricular pacing. Finally, radiofrequency catheter ablation was performed. RESULTS: Five patients had anterograde decremental conduction over the accessory pathway but had no retrograde conduction. Of the 64 patients with retrograde decremental conduction over the accessory pathway, anterograde conduction over the pathway was absent in 41 (64%), intermittent in 5 (8%) and nondecremental in 18 (28%). In the remaining five patients, anterograde and retrograde decremental conduction over the same pathway was found. The anterograde and retrograde conduction properties and extent of decrement did not differ between anterograde and retrograde decremental pathways. Posteroseptal pathways had the highest incidences of anterograde and retrograde decremental conduction. Intravenous adenosine, procainamide and verapamil caused conduction delay or block, or both, in 10 of 10, 10 of 10 and 4 of 10 of the anterograde and 20 of 20, 20 of 20 and 8 of 20 of the retrograde decremental pathways, respectively. All patients had successful ablation of the decremental pathways without complications. During the follow-up period of 31 +/- 19 months, only one patient experienced recurrence. CONCLUSIONS: Decremental accessory pathways usually had functionally distinct conduction characteristics in the anterograde and retrograde directions. Their pharmacologic responses suggested the heterogeneous mechanisms of decremental conduction.
Adenosine↗
Electrophysiologic characteristics and anatomical complexities of accessory atrioventricular pathways with successful ablation of anterograde and retrograde conduction at different sites.
INTRODUCTION: Catheter ablation may eliminate anterograde and retrograde accessory pathway conduction at closely adjacent but anatomically discrete sites. However, the mechanisms of this discrepancy, the electrophysiologic and anatomical characteristics, and information about systematic study from a large patient population are not available. The purpose of this study was to investigate the electrophysiologic characteristics and anatomical complexities of the accessory pathway in which anterograde and retrograde conduction was successfully ablated at different sites. METHODS AND RESULTS: Thirty-eight (10.9%) patients (19 men and 19 women; mean age 37 +/- 2.4 years) fulfilling the criteria of having separate ablation sites for anterograde and retrograde conduction were designated as group I, and the other 310 patients (215 men and 95 women; mean age 47 +/- 0.6 years) were designated as group II. The patients with right-sided free-wall pathways had the highest incidence (18.6%) of separate ablation sites. The anatomical distance between anterograde and retrograde directions (left anterior oblique view, 13 +/- 0.6 vs 8 +/- 0.9 mm, P < 0.01; right anterior oblique view, 17 +/- 0.6 vs 5 +/- 0.7 mm, P < 0.01), and incidence of conduction impairment in one direction after successful ablation of another direction (15% vs 78%, P < 0.05) differed significantly between left and right free-wall pathways. The mean distances obtained from left (7 +/- 0.4 vs 14 +/- 0.4 mm, P < 0.05) and right (7 +/- 1.1 vs 15 +/- 0.9 mm, P < 0.05) anterior oblique views were shorter in patients who had impairment of conduction properties than those in patients without impaired conduction after successful ablation of one direction. CONCLUSIONS: This study showed that anatomical and functional dissociation of the accessory pathway into anterograde and retrograde components was possible. Further study on the relation between electrophysiologic and pathologic characteristics would be helpful to confirm these findings.
Adolescent↗
Dimension and related anatomical distance of Koch's triangle in patients with atrioventricular nodal reentrant tachycardia.
INTRODUCTION: The dimension of Koch's triangle in patients with AV nodal reentrant tachycardia has not been well described. Understanding the dimension and anatomical distance related to Koch's triangle might be useful in avoiding accidental AV block during ablation of the slow pathway. The purposes of this study were to define the dimension of Koch's triangle and its related anatomical distance and correlate these parameters with the successful ablation sites in patients with AV nodal reentrant tachycardia. METHODS AND RESULTS: We studied 218 patients with AV nodal reentrant tachycardia. The distance between the presumed proximal His-bundle area and the base of the coronary sinus orifice (DHis-OS) measured in the right anterior oblique view was used to define the dimension of Koch's triangle. The distance of the proximal His-bundle recording site from the successful ablation site (DHis-Ab) and the distance as a fraction of the entire length of Koch's triangle (DHis-Ab/DHis-Os) were determined. The mean DHis-Os and DHis-Ab were 25.9 +/- 7.9 and 13.4 +/- 3.8 mm, respectively. DHis-Os negatively correlated with patient age (r = -0.41, P < 0.0001) and body mass index (r = -0.18, P = 0.004). Among the patients with successful ablation sites in the medial area, DHis-Os was longer (27.2 +/- 6.6 vs 24.6 +/- 8.4 mm, P < 0.005), DHis-Ab was similar (12.9 +/- 3.1 vs 13.9 +/- 4.0, P > 0.05) and DHis-Ab/DHis-Os was smaller (0.48 +/- 0.04 vs 0.74 +/- 0.11, P < 0.05). Furthermore, the patients with successful ablation sites in the medial location needed more radiofrequency pulse numbers than those in the posterior location (6 +/- 4 vs 4 +/- 3, P < 0.05). CONCLUSION: The site of successful slow pathway ablation was consistently about 13 mm from the site recording the proximal His-bundle deflection in patients with AV nodal reentrant tachycardia despite marked variability in the dimensions of Koch's triangle; therefore, patients with large triangles required ablation in the medial region rather than the posterior region. Care should be taken when delivering radiofrequency energy to the posteroseptal area in patients with shorter DHis-Os to avoid injury to AV node.
Adolescent↗
Paradox of accessory pathway block after radiofrequency ablation in patients with the Wolff-Parkinson-White syndrome.
Although pacing technique has demonstrated that the most common site of conduction block in a manifest accessory pathway (AP) was between the AP and the ventricle, most of the block sites have been found to be between the atrium and AP after successful radiofrequency ablation. Furthermore, the block site in a concealed AP after successful radiofrequency catheter ablation has not been reported in the literature, and comparisons between a manifest and concealed AP have not been performed. This study included 219 consecutive patients undergoing successful radiofrequency catheter ablation of a single AP. AP potential was recorded at the successful target site in 76 of 92 (82.6%) patients with manifest APs, and in 99 of 127 (77.9%) patients with concealed APs. All the left-sided APs (including left posteroseptal APs) were ablated by a ventricular approach, and right-sided APs (including anteromidseptal and right posteroseptal APs) were ablated by an atrial approach. The site of conduction block was determined by analyzing and comparing the local electrograms recorded before and after radiofrequency ablation at successful ablation sites. Conduction block of manifest APs was between the atrial-AP (A-AP) in 69 patients (75%) and between the AP-ventricle (AP-V) interface in 7 patients (7.6%), whereas the conduction block of concealed APs occurred between the AP-V in 90 patients (70.9%) and between the A-AP interface in 9 patients (7.1%). Neither the preablation electrogram nor electrophysiologic characteristics of APs predicted the site of conduction block. Furthermore, neither the location of the APs nor the position of the ablation catheter affected the block site. It was concluded that the most common site of conduction block during successful radiofrequency catheter ablation of a manifest and concealed AP was between the A-AP and AP-V interface, respectively, and the impedance mismatch theory explained only part of the findings.
Adult↗
Effects of pregnancy on first onset and symptoms of paroxysmal supraventricular tachycardia.
It is important for women to understand the risk of first onset and symptomatic exacerbation of paroxysmal supraventricular tachycardia (SVT) during pregnancy. Reports regarding the effects of pregnancy on first onset and symptomatic exacerbation of paroxysmal SVT have been controversial, and have not been conducted in a systematic fashion. Two hundred seven consecutive female patients diagnosed with symptomatic paroxysmal SVT were requested to respond to multiple questionnaires before electrophysiologic study and catheter ablation. A person-years data method was used to estimate risk of first onset of paroxysmal SVT during pregnancy. Exacerbation of paroxysmal SVT was assessed by a score scale including each of the following symptoms: palpitation, fatigue, rest dyspnea, effort dyspnea, dizziness, chest oppression, blurred vision, and syncope (total score change > 2 points). In the 107 patients with accessory pathway-mediated tachycardia, 7 patients had had a first onset of tachycardia during pregnancy (relative risk ratio 0.86, confidence interval 0.4 to 1.9, p = 0.35). In the 100 patients with atrioventricular nodal reentrant tachycardia, 1 patient had had the first onset of tachycardia during pregnancy (relative risk ratio 0.11, confidence interval 0.02 to 0.56, p = 0.004). Otherwise, 14 of the 63 patients (22%) with tachycardia in the pregnant and nonpregnant periods had exacerbation of symptoms during pregnancy. Thus, first onset of paroxysmal SVT during pregnancy was rare (3.9%), and pregnancy was associated with a low risk of first onset of paroxysmal SVT. However, symptoms of paroxysmal SVT were exacerbated during pregnancy in some patients.
Adolescent↗
Recurrent tachycardia after selective ablation of slow pathway in patients with atrioventricular nodal reentrant tachycardia.
Recurrence rate of atrioventricular (AV) nodal reentrant tachycardia after successful radiofrequency ablation varies widely, and the determinants of recurrent AV nodal reentrant tachycardia remain controversial. Furthermore, true or pseudorecurrence of tachycardia after successful ablation in patients with different forms of AV nodal reentrant tachycardia has not been evaluated systematically. Three hundred sixty-two patients (161 men and 201 women [mean age 52 +/- 16 years]), including 314 patients with typical-form, 10 patients with atypical-form, 4 patients with variant-form, and 34 patients with multiple-form AV nodal reentrant tachycardias, received selective radiofrequency ablation of the anterograde and/or retrograde slow AV nodal pathway. During a mean follow-up of 27 +/- 11 months, 9 patients (2.5%) experienced recurrent AV nodal reentrant tachycardia (true recurrence, group A), and 8 (2.2%) had inappropriate sinus tachycardia or paroxysmal atrial tachyarrhythmias (pseudorecurrence, group B). Neither the true nor pseudorecurrence rate was different among the 4 different forms of tachycardia. Factors including presence of residual slow pathway conduction, a single AV nodal reentrant echo beat, absence of an accelerated junctional rhythm during successful ablation, facilitating induction of tachycardia by isoproterenol, radiofrequency pulse number, and successful ablation site were not associated with an increased risk of recurrent AV nodal reentrant tachycardia. The onset time of recurrent tachycardia was significantly late in group B patients (30 +/- 21 vs 292 +/- 240 days, p = 0.04). Thus, this study demonstrated that both true and pseudorecurrence could occur after successful ablation.
Adolescent↗
Radiofrequency catheter ablation of paroxysmal supraventricular tachycardia in patients with congenital heart disease.
Radiofrequency catheter ablation was performed in 21 patients who had congenital heart diseases associated with accessory pathway (AP)-mediated tachycardia (14 patients), with atrioventricular (AV) nodal reentrant tachycardia (4 patients), with intraatrial reentrant tachycardia (1 patient), with coexistent AP mediated tachycardia and AV nodal reentrant tachycardia (1 patient) and with coexistent AV nodal reentrant tachycardia and atrial tachycardia (1 patient). Congenital heart diseases diagnosed were seven with Ebstein's anomaly and six with septal defect; the others included patent ductus arteriosus, supravalvular aortic stenosis and left superior vena cava-coronary sinus fistula. Incidence of multiple APs (26.7 vs. 7.7%, P = 0.027), antidromic tachycardia (20.0 vs. 2.9%, P = 0.011), tachyarrhythmia-related syncope (26.7 vs. 7.2%, P = 0.022) and cardiac arrest (13.3 vs. 0%, P = 0.001) was higher in patients with AP and congenital heart diseases. Longer procedure (3.9 +/- 0.7 vs. 2.4 +/- 1.3 h for AP, P = 0.001; 3.0 +/- 0.7 vs. 2.5 +/- 0.8 h for AV nodal reentrant tachycardia, P = 0.001), and radiation exposure times (102 +/- 27 vs. 35 +/- 23 min for AP, P = 0.001; 62 +/- 23 vs. 20 +/- 11 min for AV nodal reentrant tachycardia, P = 0.001) were necessary to achieve a high success rate (95%) in patients with congenital heart disease.
Adolescent↗
Initial onset of accessory pathway-mediated and atrioventricular node reentrant tachycardia after age 65: clinical features, electrophysiologic characteristics, and possible facilitating factors.
OBJECTIVE: To evaluate the clinical features electrophysiologic characteristics, and possible facilitating factors in older patients (> or = 65 years) with initial onset of accessory pathway-mediated and atrioventricular (AV) node reentrant tachycardia. DESIGN: Of the patients undergoing electrophysiologic study and radiofrequency catheter ablation of accessory pathway-mediated and AV node reentrant tachycardia at this institution, patients with initial tachyarrhythmia after age 65 years were compared with those presenting initially before age 30. SETTING: A tertiary medical center for the general public. PARTICIPANTS: Sixty-six patients had their initial symptoms after age 65: Group I, 32 patients with accessory pathway-mediated tachycardia, and Group II, 34 patients with AV node reentrant tachycardia. Four-hundred forty patients had their initial symptoms before age 30: Group III, 283 with accessory pathway mediated tachyarrhythmia, and Group IV, 157 with AV node reentrant tachycardia. INTERVENTION: All patients underwent electrophysiological study to determine the mechanisms of tachyarrhythmia, and radiofrequency catheter ablation for treatment of tachycardia. RESULTS: (1) Older patients with initial arrhythmia had incidence of critical clinical manifestations, including tachyarrhythmia-related syncope and cardioversion, similar to those with initial arrhythmia at a younger age. (2) Patients in Group III, showed anterograde effective refractory period (ERP) of the AV node (P = .432), longer anterograde ERP of the accessory pathway (P = .004), and greater difference of the anterograde ERP between the AV node and the accessory pathway (D-ERP) (P = .003) similar to patients in group I. In Group II, the ERP and Wenckebach cycle length of the retrograde fast pathway was significantly longer than in Group IV (P = .037 and P < .001, respectively), and a greater percentage of patients in Group II than in Group IV AV node reentrant tachycardia needed isoproteronol to facilitate the induction of reentrant tachycardia (P = .034). (3) Patients in Group I and Group II had a higher incidence of supraventricular and ventricular ectopic activity than those in Group III (P = .002 and P = .005, respectively) and Group IV (P = .024 and P = .012, respectively) in 24-hour ambulatory electrocardiograms. CONCLUSION: The initial onset of accessory pathway-mediated tachycardia after age 65 may be caused by changes of electrophysiologic properties (greater D-ERP) as well as increased supraventricular and ventricular ectopic activity. Influence of the autonomic nervous system, rather than changes of conduction properties in the AV node, and increase in ectopic activity may contribute to the new onset of AV node reentrant tachycardia in older adults. The choice of antiarrhythmic drugs and radiofrequency ablation require attention to the clinical profile and facilitating factors of reentrant tachycardia in this group of patients.
Adult↗
Accessory atrioventricular pathways and atrioventricular nodal reentrant tachycardia in teenagers. Electrophysiologic characteristics and radiofrequency catheter ablation.
UNLABELLED: Accessory pathway-mediated tachyarrhythmias and AV nodal reentrant tachycardia represent a large portion of supraventricular tachycardia in younger patients. Reports comparing electrophysiologic characteristics and results of radiofrequency ablation between teenagers and adults from the same electrophysiology laboratory are rare, and these deserve further study. This study included 49 teenage patients (mean age 17 +/- 3 years, range from 10 to 20) and 1008 adult patients (mean age 50 +/- 13 years, range from 21 to 92) referred for electrophysiologic study and radiofrequency ablation for treatment of accessory pathway-mediated and AV nodal reentrant tachycardia. The results showed that: (1) mean duration of tachyarrhythmia was shorter in teenagers, but incidences of syncope, cardioversion for hemodynamic compromise and associated cardiovascular diseases were similar in both groups; (2) teenagers had a higher incidence of right-sided free wall accessory pathways (34.1% vs 14.9%, p = 0.048) and better conduction properties of accessory pathways and AV nodal pathways; (3) fast-slow and multiple forms of AV nodal reentrant tachycardia were significantly less frequent (p = 0.026) in teenagers, whereas atrial fibrillation with ventricular preexcitation was common in adults; (4) success rate, incidence of recurrent tachycardia, total procedure time, radiation exposure time and number of radiofrequency pulses for successful ablation did not differ significantly between teenagers and adults. IN CONCLUSION: (1) different electrophysiologic characteristics were found between teenagers and adults; and (2) radiofrequency ablation was effective and safe in teenagers with paroxysmal supraventricular tachycardia.
Adolescent↗