Characteristics and radiofrequency ablation in posteroseptal and left free-wall subepicardial accessory pathways

Accessory pathways (APs) that can only be ablated from the coronary sinus are likely to be located subepicardially. The electrocardiographic (ECG) and electrophysiological characteristics as well as the immediate radiofrequency ablation success rate and the recurrence rate were compared in 15 patients (11 posteroseptal and 4 left free-wall) with subepicardial APs and in 31 control patients with posteroseptal (15) and left free-wall (16) APs matched with age, sex, and AP location during the same study period in whom APs were successfully ablated from the endocardial approach. Patients with posteroseptal subepicardial APs had a longer tachycardia cycle length (355 +/- 32 vs 286 +/- 49 milliseconds, P < .05), a lower success rate (9 /11 vs 15/15, P = .09), and a higher recurrence rate (3/9 vs 0/15, P < .05) as compared with control patients. A negative delta wave with QS or QR pattern in lead II was present in all 4 patients with a manifest posteroseptal subepicardial AP located in the middle cardiac vein as compared with none of the 5 control patients with posteroseptal APs located in the proximal coronary sinus and 1 of the 9 control patients (P < .01). A positive delta wave in lead I along with an R/S of less than 1 in lead V 1 , and a negative delta wave in lead II, was noted in 1 of the 2 patients with left free-wall subepicardial APs and none of the 7 controls (P = .047). The local activation time is significantly shorter in the 4 patients with left free-wall subepicardial AP than in the 16 control patients (31 +/- 9 vs 89 +/- milliseconds, P = .044). CONCLUSIONS: Some ECG characteristics are suggestive of APs located in the middle cardiac vein and left free-wall subepicardial site, while a longer local activation time is characteristic of left free-wall APs. The success rate is lower and the recurrence rate higher with radiofrequency ablation in patients with subepicardial AP.     

Clinical characteristics and electrophysiologic properties of atrioventricular accessory pathways: importance of the accessory pathway location.

OBJECTIVES. This study was designed to assess the influence of accessory atrioventricular (AV) pathway location on the clinical and electrophysiologic characteristics of 384 consecutive symptomatic patients having a single accessory pathway. METHODS. Four locations were studied: left free wall (n = 270), posteroseptal (n = 52), anteroseptal (n = 29) and right free wall (n = 33). Ten clinical variables and 12 electrophysiologic variables were analyzed, including the effective refractory period of the accessory pathway and the different clinically occurring and inducible arrhythmias. RESULTS. Only two clinical findings were associated with accessory pathway location: 1) later age at onset of symptoms in the left free wall versus other accessory pathway locations (24 +/- 12 vs. 20 +/- 11 years, p = 0.02), and 2) later age at the time of electrophysiologic study in the left free wall accessory pathway location (36 +/- 13 vs. 32 +/- 11 years, p = 0.01). Six electrophysiologic variables showed a correlation with the accessory pathway location: 1) retrograde conduction only was found less frequently in right free wall (9%) and anteroseptal (10%) than in left free wall (26%) and posteroseptal (29%) accessory pathway locations (p = 0.05); 2) the retrograde effective refractory period of the accessory pathway was shorter in anteroseptal (253 +/- 52 ms) and left free wall (270 +/- 72 ms) as compared with right free wall (296 +/- 101 ms) and posteroseptal (301 +/- 76 ms) locations (p = 0.05); 3) retrograde decremental conduction over the accessory pathway was present in the posteroseptal (17%) and left free wall (3%) but absent in the other locations (p less than 0.001); 4) anterograde decremental conduction was only seen in the right free wall location (12%) (p less than 0.001); 5) orthodromic reentrant tachycardia was induced less frequently in the right free wall than in other locations (70% vs. 93%, p less than 0.001); and 6) inducibility of atrial fibrillation was greater in anteroseptal (62%) than in right free wall (21%), left free wall (44%) and posteroseptal (36%) locations (p = 0.01). CONCLUSIONS. The location of the accessory AV pathway is associated with specific electrophysiologic characteristics.     

Electrocardiographic and electrophysiologic characteristics of anterior, midseptal and right anterior free wall accessory pathways.

OBJECTIVES. The objective of this study was to define the electrocardiographic (ECG) and electrophysiologic characteristics of midseptal, anteroseptal and right anterior free wall accessory pathways. METHODS. The fully pre-excited 12-lead surface ECGs and ECGs during orthodromic atrioventricular (AV) reentrant tachycardia were compared for 13 patients with an anteroseptal, 7 with a midseptal and 7 with a right free wall accessory pathway. Routine electrophysiologic studies were performed in all and stimulation of the right ventricular summit during tachycardia was accomplished in 10 patients. RESULTS. Differences in the surface ECGs were not sufficiently sensitive to distinguish among accessory pathway locations. Premature ventricular complexes induced from the right ventricular septal summit during ventricular activation either advanced the succeeding atrial depolarization or terminated the tachycardia in three of six patients with a septal pathway and in none of the four with a right anterior pathway. The change in ventriculoatrial (VA) interval with the development of right bundle branch block during orthodromic AV tachycardia proved most helpful in distinguishing these pathways. Patients with a right anterior free wall pathway showed a change in VA interval > or = 40 ms, whereas those with an anteroseptal pathway showed changes of 20 to 30 ms and those with a midseptal pathway showed no change. CONCLUSIONS. Anteroseptal, midseptal and right anterior free wall pathways may be distinguished by using programmed stimulation of the summit of the right ventricular septum and especially with changes in the VA interval with development of right bundle branch block during orthodromic AV reentrant tachycardia.     

Electrocardiographic and electrophysiologic characteristics of midseptal accessory pathways

BACKGROUND : The purpose of the present study was to investigate the electrocardiographic and electrophysiologic characteristics of right midseptal (RMS) and left midseptal (LMS) accessory pathways (APs), and to develop a stepwise algorithm to differentiate RMS from LMS APs. METHODS AND RESULTS: From May 1989 to February 2004, 1591 patients with AP-mediated tachyarrhythmia underwent RF catheter ablation in this institution, and 38 (2.4%) patients had MS APs. The delta wave and precordial QRS transition during sinus rhythm, retrograde P wave during orthodromic tachycardia, and electrophysiologic characteristic and catheter ablation in 30 patients with RMS APs and 8 patients with LMS APs were analyzed. There was no significant difference in electrophysiologic characteristics and catheter ablation between RMS and LMS APs. The polarity of retrograde P wave during orthodromic tachycardia also showed no statistical difference between patients with RMS and LMS APs. The delta wave polarity was positive in leads I, aVL, and V3 to V6 in patients with RMS and LMS APs. Patients with LMS APs had a higher incidence of biphasic delta wave in lead V1 than patients with RMS APs (80% vs. 15%, P=0.012). The distributions of precordial QRS transition were different between RMS APs (leads V2; n = 10, V3; n = 7 and V4; n = 3) and LMS APs (leads V1; n = 1 and V2; n = 4) (P = 0.03). The combination of a delta negative wave in lead V1 or precordial QRS transition in lead V3 or V4 had a sensitivity of 90%, specificity of 80%, positive predictive value of 95%, and negative predictive value of 66% in predicting an RMS AP. CONCLUSIONS: Delta wave polarity in lead V1 and precordial QRS transition may differentiate RMS and LMS APs.     

Atrial tachycardias originating from the atrial septum: electrophysiologic characteristics and radiofrequency ablation

INTRODUCTION: The characteristics of atrial tachycardia (AT) have varied widely among different reports. The anatomic locations of ATs may bias the results. We propose that septal ATs and free-wall ATs have different characteristics. METHODS AND RESULTS: One hundred forty-one patients with AT underwent electropharmacologic study, endocardial mapping, and radiofrequency ablation. Forty-nine (34.7%) patients had septal AT originating from the anteroseptal, mid-septal, and posteroseptal areas. Tachycardia cycle length was similar between septal AT and free-wall AT (367 +/- 46 msec vs 366 +/- 58 msec, P > 0.05). More patients with septal AT required isoproterenol to facilitate induction (44.9% vs 31.5%, P <.0.05). Septal AT was more sensitive to adenosine than free-wall AT (84.4% vs 67.8%, P < 0.05). Only posteroseptal AT showed a positive P wave in lead V1 and negative P wave in all the inferior leads (II, III, aVF). Radiofrequency catheter ablation had a comparable success rate for septal AT and free-wall AT (96% vs 95%) without impairment of AV conduction. During follow-up of 49 +/- 13 months (range 17 to 85), the recurrence rate was similar for septal AT and free-wall AT (3.2% vs 4.6%, P = 0.08). CONCLUSION: Septal AT has electrophysiologic characteristics that are distinct from those of free-wall AT. Catheter ablation of the septal AT is safe and effective.     

Long-term results of radiofrequency catheter ablation in patients with multiple accessory pathways

Information on the long-term results of radiofrequency catheter ablation in a large group of patients with multiple accessory pathways (APs) was not available. This study included 858 patients with Wolff-Parkinson-White syndrome who underwent electrophysiologic study and radiofrequency catheter ablation: 73 patients (8.5%) had multiple APs. Sixty-six patients had 2 APs, 5 had 3 APs, 1 had 4 APs, and 1 had 5 APs. The most common combination pattern of these pathways were concealed APs (38 patients, 52%). Localization of accessory pathways showed a higher incidence of right free wall (22% vs 11%, p < 0.05), anteroseptal, and midseptal APs (9% vs 5%, p < 0.05) in patients with multiple APs than in patients with 1 AP. The most common anatomic sites for multiple APs were 2 APs in the left wall (21 patients, 28%). Although the success rate was similar (98% vs 99%, p > 0.05), procedure time (3.1 ± 1.2 vs 2.0 ± 1.1 hours, p < 0.05) and radiation exposure time (48 ± 26 vs 29 ± 19 minutes, p < 0.05) were longer in patients with multiple APs. The recurrence rate was higher in patients with multiple APs (9.5% vs 2.5%, p < 0.05), and the most common site of recurrent APs was in the left free wall (7.2%); in contrast, it was in the right free wall in patients with 1 AP. These findings demonstrated that a high success rate of radiofrequency catheter ablation was found in patients with multiple APs; however, the higher recurrence rate in patients with multiple APs should be considered.     

Pace mapping of Koch's triangle reduces risk of atrioventricular block during ablation of atrioventricular nodal reentrant tachycardia

INTRODUCTION: Slow pathway (SP) ablation of AV nodal reentrant tachycardia (AVNRT) can be complicated by second- to third-degree AV block. We assessed the usefulness of pace mapping of Koch's triangle in preventing this complication. METHODS AND RESULTS: Nine hundred nine consecutive patients undergoing radiofrequency ablation of AVNRT were analyzed. Group 1 (n=487) underwent conventional slow pathway ablation. Group 2 (n=422) underwent ablation guided by pace mapping of Koch's triangle, which located the anterogradely conducting fast pathway (AFP) based on the shortest St-H interval obtained by stimulating the anteroseptal, midseptal, and posteroseptal aspects of Koch's triangle. In group 2, AFP was anteroseptal in 384 (91%), midseptal in 33 (7.8%), and posteroseptal or absent in 5 (1.2%). In 32 of 33 patients with midseptal AFP, slow pathway ablation was performed strictly in the posteroseptal area. In 4 of 5 patients with posteroseptal or no AFP, retrograde fast pathway was ablated. Two patients refused ablation. Persistent second- to third-degree AV block was induced in 7 (1.4%) of 487 group 1 patients versus 0 (0%) of 422 group 2 patients (P=0.038). Ablation was successful in all patients in whom ablation was performed. CONCLUSION: Pace mapping of Koch's triangle identifies patients in whom the AFP is absent or is abnormally close to the slow pathway. In these cases, guiding ablation helps to avoid AV block.     

Quantitative effects of functional bundle branch block in patients with atrioventricular reentrant tachycardia

Changes in the retrograde conduction time (ventriculoatrial [VA]) interval during functional bundle branch block (BBB) have been used to separate septal from free wall accessory pathways (APs), but different values of the VA interval prolongation (deltaVA) have been described in different reports. A total of 95 patients with single nondecremental APs who developed BBB during atrioventricular reentrant tachycardia were studied. Free wall APs were found in 60 patients, and 35 had septal APs. For patients with free wall APs, complete and incomplete BBB ipsilateral to the atrial insertion site of APs were observed in 39 of 60 patients (65%) and 31 of 60 patients (52%), respectively. For patients who had both complete (QRS > or = 120 ms) and incomplete (QRS <120 ms) BBB during atrioventricular reentrant tachycardia, deltaVA for patients with complete BBB was significantly greater than in those with incomplete BBB, 59 +/- 19 ms versus 30 +/- 11 ms, p <0.001. For patients with septal APs and complete and incomplete BBB during tachycardia, the mean deltaVA for those with complete BBB was 31 +/- 20 ms and was significantly longer than in patients with incomplete BBB (14 +/- 6 ms), p <0.001. There was no significant difference in deltaVA between those with free wall APs and incomplete BBB compared with those with septal APs and complete BBB. The criteria of QRS > or = 120 ms associated with deltaVA > or =40 ms served to best separate free wall from septal APs with a sensitivity of 88% and a specificity of 89%. Left anterior fascicular block was associated with marked lengthening of deltaVA for those with left free wall APs, whereas a left posterior fascicular block pattern resulted in a marked increase in the deltaVA for patients with posteroseptal APs. In the absence of fascicular block patterns, a deltaVA > or =40 ms provides strong evidence of a free wall AP, with a sensitivity of 95% and a specificity of 100%. The left posterior fascicle appears to provide predominant innervation of the posterior septum.     

隐匿性房室旁道心电图定位特征探讨

回顾分析射频消融成功的３６５例隐匿性房室旁道患者房室折返性心动过速时的逆传Ｐ（Ｐ－）波特点，并比较Ｖ１及食管导联的ＲＰ－（ＲＰ－Ｖ１和ＲＰ－Ｅ）间期，以探讨隐匿性房室旁道的定位特征。结果显示：①Ｉ、ａＶＬ导联（简称Ⅰ－Ｌ导联）显示Ｐ－波倒置的１７５例均为左心旁道，其中左游离壁旁道１５５例、左后隔旁道２０例；Ⅱ、Ⅲ、ａＶＦ导联（简称Ⅱ－Ｆ导联）显示Ｐ－深倒７０例，其中左后隔旁道５０例中有３５例（７０．０％）、右后隔旁道３０例中有２５例（８３．３％）、右游离壁旁道６０例中有１０例（１６．７％），前两者与后者分别相比差异有显著性，Ｐ均＜０．００１。②在左心旁道中，ＲＰ－Ｖ１间期与ＲＰ－Ｅ间期相比（１６６．２±１７．８ｍｓｖｓ１１８．１±１９．２ｍｓ），差异有显著性，Ｐ＜０．０１；在右心旁道中，右前膈、右游离壁旁道ＲＰ－Ｖ１间期与ＲＰ－Ｅ分别相比（１０７．１±１８ｍｓｖｓ１５７．１±１８ｍｓ，１３２．５±１８．６ｍｓｖｓ１８９．２±２３．５ｍｓ），差异有显著性，Ｐ＜０．０１）。Ⅰ－Ｌ导联Ｐ－波倒置为左心旁道的重要表现，Ⅱ－Ｆ导联Ｐ－波深倒是后隔旁道的重要特点，两个导联上Ｐ－波均直立提示右前隔旁道，左心旁道ＲＰ－Ｅ间?     

Predictors of long-term success in catheter ablation of atrioventricular nodal reentrant tachycardia: a multivariate regression analysis

BACKGROUND: To investigate the predictors of long-term success after catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT). METHODS: One-hundred and fourteen consecutive patients underwent slow pathway ablation using anteroseptal (n=24), midseptal (n=65) and posteroseptal approach (n=25). The correlation between ablation approaches, electrophysiological characteristics during and after ablation and the recurrence rate of AVNRT was analyzed by a multivariate regression analysis. RESULTS: During ablation, transient AV block in the anteroseptal, midseptal and posteroseptal approach occurred in 8.3, 4.6 and 0%, respectively (P<0.01). AVNRT recurred in seven patients after 5 years follow-up. Five recurrences (20.8%) were from anteroseptal approach group and two (3.1%) were from midseptal approach group. Multivariate regression analysis revealed that anteroseptal ablation approach and residual dual atrioventricular nodal pathway following apparently successful ablation were the predictors for recurrence of AVNRT (R=0.645, P<0.001). CONCLUSION: Anteroseptal approach of slow pathway ablation is associated with a higher incidence of transient AV block and AVNRT recurrence than other approaches. Residual dual atrioventricular nodal pathway after apparently successful ablation also carries a high risk of recurrence.     

Posteroseptal accessory pathways: an overview of anatomical characteristics, electrocardiographic patterns, electrophysiological features, and ablative therapy

First, the posteroseptal region of the heart is probably the most complex area among those that harbor AV accessory fibers and a firm grasp of the anatomical characteristics of this region may facilitate achieving a successful AP ablation. Second, there is no sharp demarcation between the posteroseptal area and its surrounding regions including mid-septal, left posterior paraseptal, and right posterior paraseptal locations. Therefore, there are some inevitable overlaps between the electrocardiographic and electrophysiological features of APs located in the posteroseptal region and those areas immediately adjacent to it. Third, in the vast majority of cases, successful ablation can be achieved using a right atrial approach. Therefore, dividing posteroseptal APs into right- or left-sided pathways may only be useful for describing their ECG or electrophysiological characteristics with little or no value in predicting the site of successful ablation. Fourth, it seems advisable to attempt efforts to induce functional bundle branch block during orthodromic tachycardia and assess its effect on the VA interval. Ventriculoatrial interval prolongation due to right bundle branch block strongly favors a right free-wall or anteroseptal AP location. Prolongation of the VA interval by 30 msec or less in response to left bundle branch block is compatible with a posteroseptal location. In this situation, the mapping and ablative efforts should primarily be focused on the right atrial approach, including the terminal coronary sinus. If left bundle branch block causes VA interval lengthening of 30 msec or greater, the AP is most likely in the left free-wall region, including the posterior paraseptal area. Finally, the presence of APs having an intimate relationship with the middle cardiac (posterior interventricular) vein or the coronary sinus pouch, although exceedingly uncommon, should be considered in difficult cases in which radiofrequency applications to the conventional posteroseptal locations are unsuccessful. Such cases may require coronary sinus venography for better visualization and precise mapping of the terminal sinus complex.     

Electrophysiologic properties of accessory atrioventricular pathways. Comparison with myocardial tissue and relation to site

In 45 patients (15 female, 30 male; age 34 +/- 12 years) with Wolff-Parkinson-White syndrome: 1) the relation between electrophysiologic properties and location of accessory pathways and 2) the relationship between electrophysiologic properties of accessory pathways and adjacent atrial and ventricular myocardium was studied. Location of the accessory pathways was determined by catheter mapping of the coronary sinus and the tricuspid valve ring. There was no linear correlation between antegrade and retrograde effective refractory periods of accessory pathways and adjacent myocardial tissue. According to their location, accessory pathways were divided into right lateral (n = 4), anteroseptal (n = 6), posteroseptal (n = 10), left posterolateral (n = 8), and left lateral (n = 17). While analysis of variance revealed no differences between subgroups concerning retrograde effective refractory periods, antegrade effective refractory periods were significantly different (p less than .01). Moving in a clockwise direction around the mitral valve ring, antegrade effective refractory periods of the accessory pathways decrease from anteroseptal (321 +/- 30 ms) to posteroseptal (290 +/- 38 ms), left posterolateral (258 +/- 21 ms) and left lateral (246 +/- 27 ms), (Spearman R = 0.70m, p less than .01). Antegrade effective refractory periods of septally located accessory pathways (301 +/- 38) were significantly longer than of pathways located in the free wall of the ventricles (251 +/- 24, p less than .01).     

Accuracy and Limitations of Published Algorithms Using the Twelve-Lead Electrocardiogram to Localize Overt Atrioventricular Accessory Pathways

INTRODUCTION: The purpose of this study was to evaluate the accuracy and limitations of published algorithms using the 12-lead ECG to localize AV accessory pathways (APs). METHODS AND RESULTS: The 11 relevant algorithms found in the literature (MEDLINE database and major scientific sessions) were tested on a series of 266 consecutive patients who successfully underwent radiofrequency catheter ablation of a single overt AV AP. The positive predictive values (PPV) of the algorithms in applicable patients were significantly lower for algorithms with > 6 accessory location sites (40.6% +/- 10.9% vs 61.2% +/- 8.0%; P < 0.03) and show a tendency for algorithms not relying on delta wave polarity but on QRS polarity only (36.6% +/- 11.2% vs 52.3% +/- 13.1%; P = 0.09). The PPV in applicable patients is related to the AP location (P < 0.001) and ranked from the highest to the lowest as follows: left lateral (mean PPV = 86.3%), posteroseptal (mean PPV = 65.2%), right anteroseptal (mean PPV = 45.2%), and right posterolateral (mean PPV = 23.4%). CONCLUSION: Our study suggests that the accuracy of algorithms relying on the 12-lead ECG depends on AP locations as defined in the algorithms and on the number of AP sites. The accuracy tends to be lower when delta wave polarity is not included in the algorithm's architecture. This should be considered when using these algorithms or when building new ones.     

Radiofrequency catheter ablation of septal accessory pathways in the pediatric age group

Radiofrequency catheter ablation (RCA) of septal accessory pathways may be technically challenging in children due to the risk of inadvertent atrioventricular (AV) block in the setting of small cardiac dimensions. Outcomes were reviewed for all patients aged < or =19 years with manifest and concealed septal accessory pathways undergoing RCA since 1990 at a single institution. One hundred forty-five procedures were performed in 127 patients (mean age 11.6 years). The number of studies according to accessory pathway location were: anteroseptal (n = 36), midseptal (n = 20), mouth of coronary sinus (n = 40), middle cardiac vein (n = 6), right posteroseptal (n = 21), and left posteroseptal (n = 22). Ablation was deferred for 9 patients (6 anteroseptal and 3 midseptal) in favor of additional pharmacologic trials. Acute success rates for targeted accessory pathways were: anteroseptal (96%), midseptal (94%), mouth of coronary sinus (88%), middle cardiac vein (100%), right posteroseptal (100%), and left posteroseptal (96%). Recurrence rates during follow-up were: anteroseptal (14%), midseptal (12%), mouth of coronary sinus (3%), right posteroseptal (4%), and left posteroseptal (4%). Permanent second or third degree AV block occurred in 4 of 136 RCA attempts (3%), involving 2 anteroseptal and 2 midseptal pathways. In 3 of these 4 cases, a high probability of block was anticipated from prior ablation efforts, prompting pacemaker insertion before or in conjunction with RCA. Thus, in the pediatric age group, acute RCA success rates for septal accessory pathways can exceed 90%. The risks of AV block and accessory pathway recurrence are most relevant to anteroseptal and midseptal pathways. These data may be factored into patient selection and the decision whether to ablate.     

Clinical, electrophysiologic and antiarrhythmic efficacy of moricizine HCl

The electrophysiologic effects and antiarrhythmic efficacy of moricizine HCl (1.5 to 2.0 mg/kg intravenously, and 600 to 800 mg orally/24 hours) were studied using electrophysiologic testing, ambulatory electrocardiographic monitoring, exercise stress testing and transesophageal stimulation of the left atrium. Moricizine HCl had no significant effects on the sinus node in patients with normal nodal function and did not depress sinoatrial conduction time even in patients with serious node dysfunction. Moricizine HCl significantly lengthened the following intervals: PA (32 +/- 5 to 40 +/- 5 ms), AH (82 +/- 13 to 92 +/- 12 ms), HV (45 +/- 12 to 50 +/- 12 ms), paced cycle length 1:1 atrioventricular node conduction (340 +/- 14 to 352 +/- 14 ms) and paced cycle length 1:1 ventriculoatrial conduction (300 +/- 14 to 400 +/- 13 ms). The refractory periods of atrium, atrioventricular node and ventricular myocardium did not change significantly, and there was no alteration of the QRS or QT intervals. The drug abolished anterograde and retrograde conduction over the accessory pathway and increased the refractory period of accessory pathway in all patients. Intravenous moricizine HCl terminated and prevented tachycardia in 72% and 68% of the patients, respectively. Oral moricizine HCl (600 to 800 mg/24 hours) prevented tachycardia in 40% of patients with a preexcitation syndrome. Intravenous moricizine HCl terminated atrioventricular nodal reentrant paroxysmal tachycardia in 66% of patients, whereas 40% responded to the oral drug. Moricizine HCl 600 to 800 mg/24 hours suppressed ventricular premature beats in 60% of patients. A similar drug, Ethacizine, had the same electrophysiologic effects as moricizine HCl but was more potent.(ABSTRACT TRUNCATED AT 250 WORDS)     

射频消融术后出现延迟性房室阻滞五例

报道5例射频消融后出现的房室阻滞及其临床转归和电生理特点。1219例房室结折返性心动过速行下位法消融慢径,208例右后间隔旁道参与的心动过速行右后间隔消融,共有5例出现延迟后(>24h)的房室阻滞。慢径消融组的患者3例分别于术后第2,3,5天出现Ⅱ度Ⅰ型房室阻滞,并于术后第4,9和14天消失。后间隔旁道消融的2例患者于第2天出现Ⅱ度Ⅰ型房室阻滞,并分别于第11,13天消失。射频消融放电20.6±8.7(11～31)次,能量30±17.2(20～50)W。放电过程中无快速的交界区心动过速或者>1个无逆传的连续交界区心律。5例在射频消融前后房室结前向和逆向传导功能均正常。结论:慢径和后间隔旁道消融均可出现延迟性房室阻滞,通常能在1～2周内恢复。     

Late occurrence of heart block after radiofrequency catheter ablation of the septal region: clinical follow-up and outcome

INTRODUCTION: There are few data regarding the occurrence of delayed heart block at least 24 hours after radiofrequency catheter ablation (RFCA) of AV nodal reentry or posteroseptal accessory pathways (APs). We investigated the late occurrence of heart block in this population, the clinical outcome, and whether findings at electrophysiologic study could have predicted its development. METHODS AND RESULTS: Two of 418 patients with AV nodal reentry undergoing RFCA using a posterior approach and 1 of 54 patients with RFCA of a posteroseptal AP developed late heart block. Anterograde and retrograde AV nodal conduction before and after RFCA were normal. Patients received 12, 15, and 32 RFCA lesions, respectively, using a mean maximum power of 44 W. The RFCA sites were the posterior septum for posteroseptal AP and the posterior and mid-septum for patients with AV nodal reentry, with no His electrogram ever recorded at the ablation site. During RFCA, junctional tachycardia occurred with 1:1 VA conduction in the patient with a posteroseptal AP, but occasional intermittent single retrograde blocked complexes were present in both patients with AV nodal reentry. No rapid junctional tachycardia or >1 consecutive retrograde blocked complex was ever observed during RFCA. Persistent high-degree AV block with junctional escape developed 2 days after RFCA in the posteroseptal AP patient. A permanent pacemaker was implanted, and normal conduction was noted 16 days after RFCA. Both patients with AV nodal reentry complained of fatigue, mainly on exertion, 3 to 4 days after RFCA, and ECG-documented exercise-induced variable AV block was obtained. Because heart block resolved in our initial patient, a prolonged monitoring period was allowed. Symptoms disappeared at 13 and 8 days, and a follow-up treadmill test showed normal PR interval and no heart block. No recurrence of heart block has been seen in any of these three patients. CONCLUSION: Late unexpected heart block after RFCA of AV nodal reentry and posteroseptal AP is rare, often resolves uneventfully in 1 to 2 weeks, and no specific electrophysiologic findings predicted its occurrence. Prolonged clinical observation is preferable to immediate pacemaker implantation in such patients.     

心室起搏对后间隔旁道与快径逆传的诊断价值

通过右室心尖部和基底部两个不同部位的起搏，比较１５例房室结折返性心动过速（对照组）和８例隐匿性后间隔旁道参与的房室折返性心动过速患者（观察组）的室房传导时间（ＶＡＩ）。结果显示：①心尖部起搏时对照组ＶＡＩ为１７４±３４ｍｓ，与观察组１８６±３８ｍｓ相比无显著性差异（Ｐ＝ＮＳ）。②基底部起搏时观察组ＶＡＩ为１５３±２４ｍｓ，明显短于对照组１９９±３４ｍｓ，两者比较有显著性差异（Ｐ＜０．０１）。③两个部位（心尖部与基底部）ＶＡＩ的差值对照组≤０（－５０～０，平均－２４±１６ｍｓ）与观察组≥１５ｍｓ（１５～７５，平均３４±１９ｍｓ）比较有非常显著性差异（Ｐ＜０．００１）。提示右室心尖部与基底部连续起搏可快速、准确地鉴别室房传导是经快径路还是后间隔旁道     

Decremental conduction properties in overt and concealed atrioventricular accessory pathways.

AIM: Most atrioventricular accessory pathways (AV-APs) exhibit Kent bundle physiology characterized by fast and non-decremental conduction properties. In contrast, atriofascicular APs, which are only capable of reaching slow levels of long antegrade decremental conduction, are uncommon. The aim of this study was to describe antegrade and/or retrograde AV-APs with unusual decremental properties. METHODS AND RESULTS: Five patients with unusual decremental AV-APs underwent electrophysiological evaluation and radiofrequency catheter ablation for symptomatic tachycardias. Three were found to have structural heart disease, and three latent decremental AV-APs in the anterograde and/or retrograde direction that could not be demonstrated by routine electrophysiological testing. In Case 1, a right posteroseptal AV-AP with bidirectionally latent decremental conduction was associated with clinical antidromic circus movement tachycardia (CMT) mimicking ventricular tachycardia and orthodromic CMT, the latter inducible only with isoprenaline. In Case 2, incessant orthodromic CMT was due to a latent retrograde left posterolateral AV-AP. In both cases, double atrial responses to a single paced ventricular beat, initiating orthodromic CMT, were observed. In Case 3 with latent preexcitation unmasked by adenosine and atrial pacing, retrograde latent decremental conduction over a right posteroseptal AV-AP could be shown only with isoprenaline. This patient and the remaining two with overt preexcitation demonstrated anterograde decremental AP conduction that was discontinuous over a right posteroseptal AV-AP in Cases 3 and 4 and was continuous over a midseptal AV-AP in Case 5. In the latter case, the site of decremental conduction could be localized at the proximal AP origin. All five AV-APs were successfully ablated at the annulus level. CONCLUSION: AV-APs with unusual decremental properties that are either latent, demonstrable only during CMT or overt, exhibiting functional longitudinal dissociation are described. These APs could be identified and successfully ablated after detailed electrophysiological analysis.     

射频消融后旁路传导复发的相关因素

射频消融房室旁路患者114例，成功地消融了125条旁路，经随访12个月，旁路复发10例（8％）。旁路复发11％～29％分布在前间隔、后间隔和右侧游离壁，左侧游离壁复发仅占4％。消融时未记录到旁路电位是很强的预示旁路复发的因素。25例未记录到旁路电位的有16％复发，而记录到旁路电位的89例仅6％复发（P＜0．01）。结论：旁路复发与消融时未记录到旁路电位以及旁路的部位有关。右侧游离壁、间隔以及隐匿性旁路复发相对较高，与旁路不能精确定位有关。