Electrocardiographic and electrophysiologic characteristics of anteroseptal, midseptal, and posteroseptal accessory pathways.

BACKGROUND: Approximately 30% of all accessory pathways (APs) are located in the septal area, and understanding the electrocardiographic and electrophysiologic of these APs is crucial for safe and effective ablation of these pathways. OBJECTIVE: In this study, the electrocardiographic and electrophysiologic characteristics of anteroseptal, midseptal, and posteroseptal APs were investigated in detail to elucidate unique electrical properties of APs in each location. METHODS: From April 2002 to October 2006, a total of 120 patients with a septal AP-mediated tachycardia were enrolled in the study. A detailed examination including electrocardiographic analysis and electrophysiologic study was performed in all patients. RESULTS: A total of 120 patients, including 98 patients with posteroseptal APs, 14 patients with anteroseptal APs, and 8 patients with midseptal APs, were studied. The anteroseptal APs could be differentiated from the midseptal APs by the 2 or more positive delta waves in inferior leads, whereas there is significant overlap in electrocardiographic features of midseptal and posteroseptal APs. The mean tachycardia cycle length was significantly shorter in patients with midseptal AP compared with those with anteroseptal and posteroseptal APs (284 +/- 49 ms vs 342 +/- 46 ms vs 350 +/- 68 ms, P = .03). The AH interval during tachycardia was also shorter in patients with midseptal APs (149 +/- 16 ms vs 200 +/- 51 ms vs 168 +/- 48 ms, P = .04). The patients with posteroseptal AP had a significantly higher incidence of atrial fibrillation (35%) than those with either midseptal (12%) or anteroseptal (14%) APs (P = .04). The patients with posteroseptal APs also had a significantly shorter antegrade effective refractory period of the AP (276 +/- 54 ms) than those with either midseptal (313 +/- 71 ms) or anteroseptal (325 +/- 61) APs (P = .036). CONCLUSION: Electrocardiographic analysis is a reliable method for differentiation of the anteroseptal from the midseptal APs, whereas the same is not true for the midseptal and posteroseptal APs. Midseptal APs were characterized by faster orthodromic tachycardia, whereas posteroseptal APs had a higher inducibility of atrial fibrillation.     

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.     

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.     

后间隔旁道体表心电图及心内电图的特征

总结射频消融成功的后间隔旁道３７例体表及心内电图特征，结果显示：显性后间隔旁道体表心电图Ⅱ、Ⅲ、ａＶＦ导联δ波负向，ＱＲＳ波群在Ｖ２导联呈Ｒ或Ｒｓ形时，若Ｖ１导联为ｒＳＲ或Ｒｓ形诊断为左后间隔旁道，其敏感性７３．３％、特异性９１．７％；Ｖ１导联为ＱＳ形诊断为右后间隔旁道，其敏感性５８．３％、特异性１００％。冠状窦电极为间距１ｃｍ的４极标测电极，近端电极置于窦口。心动过速时，心内电图ΔＶＡＨ－ＣＳ（ＶＡＨ与最短ＶＡｃｓ的差值）≥２５ｍｓ提示左侧，敏感性６２．８％、特异性９３．７％；ΔＶＡｃｓ（冠状窦电极记录的最长与最短ＶＡ的差值）≤１５ｍｓ提示左侧，敏感性８７．５％，特异性９５．４％。此外，左后间隔旁道逆行Ａ波最早出现在冠状窦近端（ＣＳｐ）或冠状窦中端（ＣＳｍ），且冠状窦中端Ａ波（Ａｃｓｍ）均早于希氏束远端（Ｈｉｓｄ）Ａ波（ＡＨｉｓｄ）；右后间隔旁道逆行Ａ波最早出现在Ｈｉｓｄ或ＣＳｐ处，Ａｃｓｍ均晚于ＡＨｉｓｄ。通过体表心电图和心内电图特征，可简便准确地预测间隔旁道的消融靶点。     

Sites of conduction block in accessory atrioventricular pathways. Basis for concealed accessory pathways

Catheter recordings of accessory pathway (AP) activation were used to identify the site of antegrade and retrograde AP conduction block in 126 consecutive patients undergoing electrophysiological testing. Activation was recorded from 89 of 121 left free-wall and posteroseptal pathways (left APs) and from 12 of 24 right free-wall, midseptal, and anteroseptal pathways (right APs). The recorded APs were further subdivided into those exhibiting consistent antegrade conduction during sinus rhythm (overt APs: 50 left APs, eight right APs), those exhibiting intermittent antegrade conduction (intermittent APs: six left APs, two right APs), and those exhibiting only retrograde conduction (concealed APs: 33 left APs, two right APs). The sites of block were recorded during decremental atrial and ventricular stimulation. The sites of both antegrade and retrograde block were determined in 40 of 50 overt left APs and six of eight overt right APs. Antegrade and retrograde block occurred at or near the AP-ventricular (AP-V) interface in 37 of 40 overt left APs and two of six overt right APs and at the atrial-AP (A-AP) interface in one of 40 overt left APs and four of six overt right APs. In three of three overt left APs with no retrograde conduction, retrograde block occurred at or near the AP-V interface. The site of antegrade and retrograde block differed in only two of 58 overt pathways. There was no difference between overt APs limited at the A-AP or the AP-V interface in the shortest atrial or ventricular pacing cycle length maintaining 1:1 antegrade or retrograde AP conduction, respectively. Both antegrade and retrograde block occurred near the AP-V interface in four of six intermittent left APs and zero of two intermittent right APs and near the A-AP interface in two of six intermittent left APs and one of two intermittent right APs. The sites of both antegrade and retrograde block were determined in 28 of 33 concealed left APs, and both occurred at or near the AP-V interface in 26 and A-AP interface in two APs. In two of two concealed right APs, antegrade block occurred at the AP-V interface. These findings suggest that both antegrade and retrograde conduction are limited by factors operating near the AP-V interface in overt left APs and at the A-AP or AP-V interface in overt right APs. Factors limiting antegrade conduction in concealed APs appear to be located almost always near the AP-V interface.     

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.     

Paraseptal Accessory Pathway in Wolff-Parkinson- White-Syndrom: Ablation from the Right,from the Left or within the Coronary Sinus/Middle Cardiac Vein?

Aims: In 1999 the consensus statement living anatomy of the atrioventricular junctions was published. With that new nomenclature the former posteroseptal accessory pathway (APs) are termed paraseptal APs. The aim of this study was to identify ECG features of manifest APs located in this complex paraseptal space.Methods and Results: ECG characteristics of all patients who underwent radiofrequency ablation of an AP during a 3 year period were analyzed. Of the 239 patients with one or more APs, 30 patients had a paraseptal AP with preexcitation. Compared to APs within the coronary sinus (CS) or the middle cardiac vein (MCV) the right sided paraseptal APs significantly more often showed an isoelectric delta wave in lead II and/or a negative delta wave in aVR. The left sided paraseptal APs presented a negative delta wave in II significantly more often compared to the right sided APs.Conclusions: According to the site of radiofrequency ablation, paraseptal APs are classified into 4 subgroups: paraseptal right, paraseptal left, inside the CS or inside the MCV. Subtle differences in preexcitation patterns of the delta wave as well as of the QRS complex exist. However, the definitive localization of APs remains reserved to the periinterventional intracardiac electrogram 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。     

Ablation of Left Free-Wall Accessory Pathways Using Radiofrequency Energy at the Atrial Insertion Site:

Transseptal versus Transaortic Ablation. Introduction: Transcatheter ablation of the left free-wall atrioventricular accessory pathways (AP) by delivery of radiofrequency current at the ventricular insertion site has been shown to be effective. The efficacy of such a technique targeting the atrial insertion site of the AP was evaluated.
Methods and Results: One hundred consecutive patients with left free-wall APs and symptomatic supraventricular tachyarrhythmias were included. APs were manifest in 55 patients and concealed in 45. There were 55 men and 45 women with a mean age of 35 years. A total of 107 left free-wall APs were identified in these patients. In these 100 patients, successful ablation was accomplished in all by using a transseptal (45 patients) or transaortic (54 patients) technique. In one patient, ablation was accomplished from within the coronary sinus. Seven patients required a repeat ablative procedure, which was performed successfully. During 107 ablative procedures, six were associated with nonfatal complications including pericardial effusion (hemopericardium) in two patients, mild mitral regurgitation in two patients, swelling of the left arm in one patient, and staphylococcal bacteremia in one patient. Eighty-two (82%) patients underwent a repeat electrophysiologic study 6 to 8 weeks after successful ablation and were found to have no functioning AP or inducible supraventricular tachycardia. During a mean follow-up of 20 ± 8 months, none of the 100 patients had a recurrence of tachyarrhythmias.
Conclusion: These data indicate that the atrial insertion site of the AP can be successfully ablated in the majority of patients with left free-wall APs by using cither a transseptal or transaortic approach. Furthermore, both techniques are associated with minimal morbidity and no mortality.     

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.     

Ablation of posteroseptal and left posterior accessory pathways guided by left atrium-coronary sinus musculature activation sequence

Introduction: While some posteroseptal and left posterior accessory pathways (APs) can be ablated on the tricuspid annulus or within the coronary venous system, others require a left-sided approach. "Fragmented" or double potentials are frequently recorded in the coronary sinus (CS), with a smaller, blunt component from left atrial (LA) myocardium, and a larger, sharp signal from the CS musculature.
Methods and Results: Forty patients with posteroseptal or left posterior AP were included. The LA–CS activation sequence was determined at the earliest site during retrograde AP conduction. Eleven APs (27.5%) were ablated on the tricuspid annulus (right endocardial), 9 (22.5%) inside the coronary venous system (epicardial), and 20 (50%) on the mitral annulus (left endocardial). A "fragmented" or double "atrial" potential was recorded in all patients inside the CS at the earliest site during retrograde AP conduction. Sharp potential from the CS preceded the LA blunt component (sharp/blunt sequence) in all patients with an epicardial AP, and in 10 of 11 (91%) patients with a right endocardial AP. Therefore, 18 of 19 (95%) APs ablated by a right-sided approach produced this pattern. The reverse sequence (blunt/sharp) was recorded in 19 of 20 (95%) patients with a left endocardial AP.
Conclusion: During retrograde AP conduction, the sequence of LA–CS musculature activation—as deduced from analysis of electrograms recorded at the earliest site inside the CS—can differentiate posteroseptal and left posterior APs that require left heart catheterization from those that can be eliminated by a totally venous approach.     

Specific Electrocardiographic Features of Manifest Coronary Vein Posteroseptal Accessory Pathways

Coronary Vein Accessory Pathways. Introduction: Some posteroseptal accessory pathways (APs) can be successfully ablated by radiofrequency current only from inside the coronary sinus (CS) or its branches, because of an absolute or relatively epicardial location. The aim of this study was to identify ECG features of manifest posteroseptal APs requiring ablation in the CS or the middle cardiac veins (MCVs). Methods and Results: One hundred seventeen consecutive patients with manifest posteroseptal APs successfully ablated: (1) ≥ 1 cm deep inside the MCV (group MCV: n = 13); (2) inside the CS, including the area adjacent to the MCV ostium (group CS: n = 10); (3) at the right (group R: n = 60); or (4) the left posteroseptal endocardial region (group L: n = 34) were included. We reviewed delta wave polarity (initial 40 msec) and QRS morphology during sinus rhythm and atrial pacing as well as electrogram characteristics in these patients. The local target site electrogram in groups MCV and CS was characterized by a longer atrial to ventricular electrogram interval, suggesting a longer course of the pathway and more frequent recording of a presumptive AP potential compared to the group ablated at the right or left endocardium. The most sensitive ECG feature for group CS or group MCV was a negative delta wave in lead II in sinus rhythm (87%), but specificity (79%) and positive predictive value (50%) were relatively low. A steep positive delta wave in aVR during maximal preexcitation possessed the highest specificity and positive predictive value (98% and 88%, sensitivity 61%) which increased to 99% and 91%, respectively, when combined with a deep S wave in V₆ (R wave ≤ S wave). Conclusion: These data suggest that posteroseptal APs ablated inside the coronary venous system have highly specific features, including the combination of a steep positive delta wave in lead aVR and a deep S wave in lead V₆ (R wave ≤ S wave) during maximal preexcitation. The highest sensitivity is provided by a negative delta wave in lead II. These findings may be helpful for anticipating and planning an epicardial ablation strategy.     

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.     

Effect of Left Atrial-Coronary Sinus Musculature Connections on the Coronary Sinus Activation Pattern via Retrograde Conduction in Patients with WPW Syndrome

BACKGROUND: Double potential (DP) activation patterns observed in coronary sinus (CS) electrograms recorded during left lateral atrial pacing, were explained by an initial low-frequency left atrial (LA) activation potential and secondary high-frequency CS musculature activation potential in canine hearts. Moreover, the connections between the LA and CS musculature vary greatly in size and location in the human heart. The purpose of this study was to investigate the relationship between the CS activation pattern during retrograde conduction via an accessory pathway (AP) and the location of left-sided APs. METHODS AND RESULTS: Fifty-one patients (31 males, mean age 48.6 years) who underwent radiofrequency catheter ablation of left-sided APs were divided into two groups according to the successful ablation site. The CS electrograms during retrograde AP conduction were classified into 3 types; single, fractionated, and DP activation patterns. A DP pattern was identified in 10 of 12 patients (83.3%) with posteroseptal to posterolateral APs, and in particular, 9 had a divergent sequence. Twenty-six of 39 patients (66.7%) with lateral to anterolateral APs, demonstrated a single pattern. The number of radiofrequency applications was significantly higher in patients with a DP pattern than in those with a single pattern (3.4 +/- 3.3 vs. 7.8 +/- 6.8, p < 0.01). CONCLUSION: Misleading information obtained when mapping for optimal ablation sites might result from DP patterns with a divergent sequence produced by discrete muscular connections between the LA and CS musculature. Ablation around left posterior APs may require meticulous observation of the CS activation patterns.     

The accuracy of locating the accessory pathway before and during surgery in patients with Wolff-Parkinson-White syndrome

The accuracy of locating the accessory pathways (APs) before and during operation in the operated 32 patients with the Wolff-Parkinson-White syndrome (WPW) was reported. There were 27 cases with the single AP, in which 17 had left-lateral free-wall pathways, 6 had left-posterior free-wall pathways, 2 had posterior septal pathways, 1 had right free-wall pathway and 1 had anterior septal pathway, and 5 cases with double APs. Taking the double APs as a single apparent AP, the accuracy was 87% (20/23) by electrocardiograms (exclusive of 9 concealed WPW), 94% (30/32) by electrophysiologic studies (EPS) and 97% (31/32) by epicardial mappings (ECM). It was difficult to discover and locate the double APs. For the 10 APs of 5 cases with double APs, the accuracy was 60% (6/10) by EPS and 70% (7/10) by ECM.     

Clinical usefulness of quantitative two-dimensional echocardiographic analysis of segmental kinesis of the left ventricle in monitoring of patients with neoplasms treated with anthracyclines]

To determine whether serial quantitative two-dimensional echocardiographic analysis of left ventricular wall motion could be effective in selecting patients in whom anthracycline treatment must be stopped, 26 patients (18 M and 8 F, mean age 10 +/- 3, range 6 to 16 years) with malignancy, receiving doxorubicin or daunomycin were followed up. Left ventricular regional wall motion abnormalities were detected in 11 patients (42%), while left ventricular ejection fraction at rest (although progressively decreased from baseline value [63 +/- 2 vs 55 +/- 2%; p = 0.0001]) was still in normal range. The following distribution of left ventricular contraction abnormalities was noted: septal, anteroseptal and posteroseptal akinesis with posterior wall hypokinesis in one patient; septal, anteroseptal and posteroseptal akinesis with anterolateral free-wall hypokinesis in another; septal, anteroseptal and posteroseptal hypokinesis in four; lateral and posterolateral free-wall hypokinesis in one; septal, anteroseptal, posteroseptal and posterior hypokinesis in four. The drug was discontinued in only two patients with akinesis, since we regarded this contraction abnormality as a predictive index of more serious and extensive myocardial damage. We began to detect hypokinesis when cumulative doses of doxorubicin or daunorubicin were 155-420 mg/m2 and 270-285 mg/m2 respectively, while akinesis was seen at doses of 395 mg/m2 of body-surface area for doxorubicin and 575 mg/m2 for daunorubicin. Follow-up examination was conducted six months after the last dose of anthracycline, and improvement or recovery of left ventricular regional wall motion abnormalities was noted in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

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?     

Angiographic patterns of coronary sinus anatomy and its relation to successful ablation sites in accessory pathway patients

BackgroundThe epicardial coronary venous system assumes importance in accessory pathway (AP) ablation especially in case of lengthy or failed attempts of ablation. Epicardial accessory pathways may be related to CS myocardial coat along one of its tributaries or to a CS diverticulum. The purpose of the present study was to use CS angiography to evaluate the relation of different patterns of CS anatomy to successful ablation sites of APs.Methods and resultsThe CS-angiographic features and incidence of structural anomalies were prospectively studied in 56 patients undergoing AP radiofrequency ablation. Retrograde CS angiography was successfully performed in 46/56 pt (82%), (33 males/13 females). The CS angiographic findings of the 46 patients were compared to the AP localization established by electrophysiological mapping and to the successful ablation sites. CS anomalies were identified in 17 (37%) patients and included the following: CS diverticulum (seven patients), funnel shaped ostium (three patients), CS aneurysm (two patients), subthebasian pouch (one patient), sharp angulation (one patient), and bulbous malformation (one patient). CS diverticuli represented (41%) of the encountered CS anomalies. Seventy-one percent of the CS diverticuli were seen in posteroseptal and left posterior locations of APs. Successful ablation site was related to CS-anomalies in seven (15.2%) patients (five patients with CS diverticulum, one patient with CS aneurysm, and one patient with CS angulation). Successful ablation was achieved from within the CS (coronary sinus – accessory pathway) (CS AP) in 10 patients (21.7%) (in relation to CS tributary in six (13%) and in relation to the neck of a CS diverticulum in four patients). CS AP represented 50% of the encountered posteroseptal and left posterior APs.ConclusionCS angiography can guide us in reaching successful ablation sites of AP inside or outside the CS. CS diverticulum is the most common CS anomaly in posteroseptal and left posterior APs.     

异丙酚对家兔心室外膜心肌细胞动作电位和L-型钙电流的影响

目的研究异丙酚对家兔左、右心室心外膜心肌细胞动作电位和L-型钙电流的影响。方法酶解法分离家兔左、右心室心外膜心肌细胞。全细胞膜片钳技术记录左、右心室心外膜心肌细胞动作电位和L-型钙电流(ICa-L)在使用异丙酚前后的变化。结果在电流钳制下,左、右心室心外膜心肌细胞动作电位都具有从0期到4期的动作电位形态,2相平台期有心外膜心肌细胞特有的穹窿样突起。异丙酚使右室心外膜心肌细胞动作电位失去2相平台期穹窿样突起,呈三角形尖锥锋形。左、右心室心外膜心肌细胞动作电位时程复极化50%和90%(APD50和APD90)在异丙酚作用后都明显缩短,其中右室心外膜心肌细胞APD50和APD90缩短最为明显(P<0.05或0.01)。在电压钳制下,异丙酚使左、右心室心外膜心肌细胞ICa-L在同一指令电位下,电流幅度均明显减小,但右室心外膜心肌细胞ICa-L的减小幅度明显强于左室同层ICa-L的减小幅度(P<0.01)。异丙酚还使左、右心室心外膜心肌细胞ICa-L的I-V曲线上移,并且使右室心外膜心肌细胞ICa-L的I-V曲线处在所有I-V曲线最上部。结论异丙酚对右室心外膜心肌细胞动作电位和ICa-L的影响程度明显强于左室,从而引起左、右心外膜心肌细胞电不均一性。     

Catheter ablation using radiofrequency current to cure symptomatic patients with tachyarrhythmias related to an accessory atrioventricular pathway

BACKGROUND. Recent investigations have shown that cure of patients with symptomatic tachyarrhythmias related to an accessory atrioventricular pathway may be achieved by closed-chest electrode catheter ablation of the accessory connection. Direct current shocks have primarily been used for this purpose, but its applicability is limited because of the lack of controlled titration of electrical energy, the infliction of barotrauma, and the need for general anesthesia. Radiofrequency current has been proposed as an alternate energy source. METHODS AND RESULTS. Seventy-three symptomatic patients with Wolff-Parkinson-White syndrome and 19 patients with only retrogradely conducting (concealed) pathways underwent ablative therapy with radiofrequency current. There were 71 accessory pathways located on the left side of the heart (57 free-wall and 14 posteroseptal pathways) and 25 on the right side (11 free-wall, seven posteroseptal, and seven midseptal or anteroseptal pathways). In patients with right-sided pathways, ablation was attempted via a catheter positioned at the atrial aspect of the tricuspid annulus. In patients with a left-sided free-wall accessory pathway, a novel approach was used in which the ablation catheter was positioned in the left ventricle directly below the mitral annulus. Accessory pathway conduction was permanently abolished in 79 patients (86%). Growing experience and improved catheter technology resulted in a 100% success rate after the 52nd consecutive patient. Failures were mainly the result of inadequate catheters used initially or an unfavorable approach to left posteroseptal pathways. CONCLUSIONS. Catheter ablation of accessory atrioventricular pathways by the use of radiofrequency current is an effective and safe therapeutic modality for patients with symptomatic tachyarrhythmias mediated by these pathways.