Electroanatomic characterization of conduction barriers in sinus/atrially paced rhythm and association with intra-atrial reentrant tachycardia circuits following congenital heart disease surgery

INTRODUCTION: The electrophysiologic mechanism of intra-atrial reentrant tachycardia (IART) is generally thought to be a macroreentrant circuit revolving around a nonconductive or highly anisotropic barrier. However, the electrical and anatomic substrate that supports these circuits has been incompletely defined. Our objectives were to characterize the atria of patients with IART using electroanatomic mapping in sinus or atrially paced rhythm and to determine whether electrical barriers identified in sinus/atrially paced rhythm are associated with IART circuits. METHODS AND RESULTS: Eighteen patients with IART and a remote history of repaired or palliated congenital heart disease were studied [8 biventricular repair, 8 single ventricle palliation (7 Fontan), and 2 Mustard repair]. Thirteen patients had a right AV valve. In sinus/atrially paced rhythm, electrical evidence of a crista terminalis was identified in 11 patients, an atriotomy in 12, and > or = 1 right atrial free-wall scar in 11. In 26 IART circuits characterized, 12 used the right AV valve as a central obstacle, 6 used a right atrial free-wall scar, 3 used an atriotomy, 3 used the crista terminalis, and 2 circuits used an atrial septal scar. All central obstacles used by IART circuits were identified in sinus/atrially paced rhythm. CONCLUSION: The crista terminalis, atriotomy, and right atrial scars can be identified in patients with repaired congenital heart disease by electroanatomic mapping in sinus/atrially paced rhythm. These conduction barriers frequently function as the central obstacle for IART. Demonstration of such features may help focus investigational mapping without reliance on spontaneous initiation of the tachycardia.     

先天性心脏病术后心房内折返性心动过速的射频消融

先天性心脏病术后常常发生心房内折返性心动过速(IART)而且治疗困难。本研究的目的是观察疤痕下方2下腔静脉开口或/和下腔静脉2三尖瓣环峡部消融的疗效。11例患者12种房性心动过速进行电生理检查和射频消融。在双电位区域仔细寻找碎裂电位和A波最早处为消融开始的靶点,并向自身解剖形成的传导障碍区延伸。结果:10例11种房性心动过速射频消融成功,成功率为11/12(91.7%),8种心动过速的成功靶点位于右心房外侧壁疤痕下方,3例为典型心房扑动的峡部。平均放电次数为5±4次。随访17±6个月,10例无心动过速发作。结论:疤痕2下腔静脉之间或/和下腔静脉2三尖瓣峡部消融可以有效的消除先天性心脏病术后的IART。     

Pericaval and periannular intra-atrial reentrant tachycardias in patients with congenital heart disease

INTRODUCTION: Intra-atrial reentrant tachycardia (IART) is a frequent late sequel of congenital heart surgery, often involving the cavotricuspid isthmus. In this report, we characterize pericaval reentry, a novel mechanism of isthmus-dependent IART in congenital heart patients, and compare its electrophysiologic characteristics with periannular atrial flutter. METHODS AND RESULTS: Electrophysiologic and electroanatomic mapping data and acute outcomes were reviewed in postoperative patients with congenital heart disease who underwent electrophysiologic study/radiofrequency catheter ablation at The Children's Hospital, Boston between January 1999 and November 2000. The study included all congenital heart patients with IART and who had undergone (1) the Fontan procedure and (2) a biventricular surgical repair other than atrial switch procedures. Thirty-seven IARTs were mapped in 22 Fontan patients. Twelve of 37 IARTs (33%) that revolved about the inferior vena cava (IVC) and involved the isthmus between the IVC and the tricuspid dimple/right-sided AV valve were identified in 12 patients (48%). Mean pericaval IART cycle length was 332 +/- 60 msec (range 240-410). An adjacent or surrounding area of scarring was observed in 10 of 12 IARTs. Slow zones (mean activation latency 39% +/- 11% IART cycle length) were detected in 8 of 12 circuits. The boundaries of the zone of slow conduction were scar-low crista (6) and scar-IVC (2). Periannular IART with CL 289 +/- 65 ms was observed in 14 of 20 patients with 4-chambered hearts. Slow zones (mean activation latency 28 +/- 9% IART cycle length) were found in 8 of 14 circuits. In both forms of IART, the predominant direction of activation of the isthmus was lateral to septal; 83% in pericaval IART and 87% in periannular IART. Radiofrequency catheter ablation successfully terminated 11 of 11 pericaval and 13 of 14 periannular IARTs. CONCLUSION: Pericaval reentry is a novel and ablatable mechanism of IART in patients specific to the Fontan procedure. It is distinguished from periannular atrial reentry by its association with Fontan anatomy, longer cycle lengths, and occurrence of a prominent discrete zone(s) of slow conduction. Both pericaval and periannular reentry show a marked preference for utilization of the isthmus in a lateral-to-septal direction.     

Coexistence of type I atrial flutter and intra-atrial re-entrant tachycardia in patients with surgically corrected congenital heart disease

OBJECTIVES: This study assessed the coexistence of intra-atrial re-entrant tachycardia (IART) and isthmus-dependent atrial flutter (IDAF) in patients presenting with supraventricular tachyarrhythmias after surgical correction of congenital heart disease (CHD). BACKGROUND: In patients with CHD, atrial tachyarrhythmias may result from IART or IDAF. The frequency with which IART and IDAF coexist is not well defined. METHODS: Both IDAF and IART were diagnosed in 16 consecutive patients using standard criteria and entrainment mapping. Seven patients had classic atrial flutter morphology on surface electrocardiogram (ECG), whereas nine had atypical morphology. RESULTS: A total of 24 circuits were identified. Three patients had IDAF only, five had IART only, seven had both, and one had a low right atrial wall tachycardia that could not be entrained. Twenty-two different reentry circuits were ablated. Successful ablation was accomplished in 13 of 14 (93%) IART and 9 of 10 (90%) IDAF circuits. There was one IART recurrence. The slow conduction zone involved the region of the right atriotomy scar in 12 of 14 (86%) IART circuits. No procedural complications and no further recurrences were seen after a mean follow-up of 24 months. CONCLUSIONS: Both IDAF and IART are the most common mechanisms of atrial re-entrant tachyarrhythmias in patients with surgically corrected CHD, and they frequently coexist. The surface ECG is a poor tool for identifying patients with coexistent arrhythmias. The majority of IART circuits involve the lateral right atrium and may be successfully ablated by creating a lesion extending to the inferior vena cava.     

Mapping of intraatrial reentrant tachycardias by remote magnetic navigation in patients with d-transposition of the great arteries after mustard or senning procedure

Introduction: Mapping of intraatrial reentrant tachycardia (IART) still presents a challenge in complex congenital heart disease. The goal of this work was to present our initial experience with remote magnetic navigation (RMN) for mapping of IART in four patients after the atrial switch procedure (Mustard n = 1, Senning n = 3) for d‐transposition of the great arteries. Methods: Three‐dimensional (3D) mapping of the systemic venous atrium and the pulmonary venous atrium (PVA) was performed using RMN (Niobe) in conjunction with 3D mapping (CartoRMT). The maps were fused with a CT‐based 3D anatomy. Results: All patients had cavotricuspid isthmus‐dependent IART with a mean atrial cycle length of 305 ms. Mapping of both atria (PVA retrogradely by passing the aortic and tricuspid valve) was feasible and safe. The procedure time for IART mapping ranged from 210 to 320 minutes with a mean of 251 minutes. The fluoroscopy time for IART mapping ranged from 15.8 to 45.0 minutes (mean 31.6 minutes) for patients, and ranged from 12.3 to 24.3 minutes with a mean of 19.5 minutes for physicians. No procedural complications occurred. Conclusion: Precise mapping of IART in the complex anatomical structures after an atrial switch procedure was feasible and safe using RMN. The maneuverability of the catheter was possible even with a retrograde access crossing two valves. Further reduction of procedural and fluoroscopy times for both patients and physicians seems possible     

Electroanatomic mapping of entrained and exit zones in patients with repaired congenital heart disease and intra-atrial reentrant tachycardia

BACKGROUND: Characterization of reentrant circuits and targeting ablation sites remains difficult for intra-atrial reentrant tachycardias (IART) in congenital heart disease (CHD). METHODS AND RESULTS: Electroanatomic mapping and entrainment pacing were performed before successful ablation of 18 IART circuits in 15 patients with CHD. Principal features of IART circuits were atrial septal defect (4 patients), atriotomy (3 patients), other atrial scar (3 patients), crista terminalis (3 patients), and right atrioventricular valve (5 patients). A median of 176 sites (range, 96 to 317 sites) was mapped for activation and 13 sites (range, 9 to 28 sites) for entrainment response. Postpacing intervals within 20 ms of tachycardia cycle length and stimulus-to-P-wave intervals of 0 to 90 ms (exit zones) were mapped to atrial surfaces generated by electroanatomic mapping. Criteria for entrainment were met over a median of 21 cm2 of atrial surface (range, 2 to 75 cm2), 19% (range, 1% to 81%) of total area tested. Using integrated data, relations between activation sequence and protected corridor of conduction could be inferred for 16 of 17 LARTs. Successful ablation was achieved at a site distant from the putative protected corridor in 9 of 18 (50%) circuits. CONCLUSIONS: The right atrium in CHD supports a variety of IART mechanisms. Fusion of activation and entrainment data provided insight into specific IART mechanisms relevant to ablation.     

Chronotropic incompetence in young patients with late postoperative atrial flutter: a case-control study.

AIMS: Atrial flutter causes late postoperative morbidity in congenital heart disease (CHD). Sinoatrial node dysfunction is associated with late postoperative atrial flutter, but pacing interventions driven by minimum heart rates (HR) have yielded mixed results. METHODS AND RESULTS: A retrospective case-control study was used to test the hypothesis that late postoperative atrial flutter is associated with chronotropic incompetence in active young CHD patients. Control CHD patients aged < or =18 years without documented supraventricular ectopy (n = 42) were matched with 42 patients (cases) having atrial flutter onset > or =6 months postoperatively. Minimum, average, and maximum non-flutter HRs were obtained from outpatient ambulatory 24 h ECG (Holter) recordings and graded exercise tests. Chronotropic competence was assessed using percentage of age-specific predicted maximum HR achieved, and calculated chronotropic index. Effects of rate-adaptive programming and maximum atrial pacing rates were analysed in 19 permanently paced cases. Least square estimates of minimum HRs were similar in cases and controls (54+/-2 vs. 52+/-2 bpm). Average HRs were lower in cases (75+/-2 vs. 81+/-2 bpm, P=0.02). Cases and controls differed most significantly with respect to percentage of predicted maximum HR achieved (67+/-2 vs. 80+/-2%, P < 0.001). This difference remained highly significant when the data were adjusted for age, sex, permanent pacing, and negatively chronotropic medication usage at the time of testing. Among paced patients, atrial flutter was significantly less likely to be observed in the setting of rate-adaptive pacing [odds ratio (OR) = 0.36; P < 0.05], and the likelihood of detecting atrial flutter decreased relative to the maximum programmed atrial pacing rate (OR 0.87 for every 5% increment in maximum pacing rate relative to maximum predicted HR for age; P < 0.05). CONCLUSION: Late postoperative atrial flutter is associated with chronotropic incompetence in paediatric CHD patients.     

Evolving electroanatomic substrate and intra-atrial reentrant tachycardia late after Fontan surgery

Atrial Remodeling After the Fontan Operation. Introduction: The prevalence of intra‐atrial reentrant tachycardia (IART) increases with age in Fontan patients. This study aimed to characterize the atrial electroanatomic substrate for IART late after Fontan surgery. Methods and Results: Detailed electroanatomic mapping of the right atrium (RA) was performed in 11 consecutive patients (33 ± 9 years) with older style Fontan circulation (atriopulmonary and atrioventricular connection) who underwent their first radiofrequency catheter ablation (RFCA) for IART. A comparative group of 30 non‐Fontan congenital heart disease (CHD) patients were also studied. Fontan patients had larger RA (P = 0.004), larger low‐voltage area ≤0.5 mV (P = 0.01), and more fractionated potentials (P < 0.001) than non‐Fontan CHD patients. RA enlargement correlated significantly with both low‐voltage zones (Spearman ρ= 0.68, P < 0.001) and fractionated potentials (Spearman ρ= 0.48, P = 0.001). Among Fontan patients, both age and time since Fontan surgery were significantly correlated to the amount of low‐voltage areas (Spearman ρ= 0.87, P < 0.001; Spearman ρ= 0.63, P = 0.04, respectively). Successful RFCA was accomplished in 30 (73%) patients and was less likely in Fontan patients (54% vs 83%, P = 0.04). Larger RA was significantly associated with a lower success rate (P = 0.04). During a follow‐up duration of 2.3 ± 1.6 years, IART recurred in 47% of patients. Larger RA size and larger low‐voltage areas predicted IART recurrence after RFCA. Conclusion: Fontan patients demonstrate progressive adverse atrial electrical remodeling with increasing age and time since surgery. Newer strategies beyond surgical incisions, such as pharmacotherapies that retard the progression of atrial fibrosis, may be required to reduce the long‐term risk of atrial arrhythmias.     

Activation mapping of reentry around an anatomic barrier in the canine atrium. Observations during entrainment and termination

We determined total right atrial activation sequences during entrainment and termination of flutter induced in dogs with a surgically induced atrial lesion. This type of atrial flutter is due to circus movement of an impulse around the tricuspid valve orifice. We recorded simultaneously from 96 bipolar intracavity electrodes in the right atrium of the isolated, perfused heart. By constructing isochronal maps, we demonstrated the pattern of atrial activation during atrial pacing protocols that either entrained or entrained and then terminated the reentrant rhythm. We show that during pacing the antidromic wavefront from the paced impulse (An) collides with the orthodromic wavefront from the previous paced impulse (On-1). During entrainment, the site of collision of the orthodromic and antidromic wavefronts was constant during pacing at a fixed rate but shifted in the antidromic direction as the pacing rate increased. Furthermore, the last paced beat was entrained only up to the site of collision of the previous paced beat. During one period of entrainment, termination of the reentrant arrhythmia occurred because On-1 blocked in the reentrant pathway due to refractory tissue left by On-2. However, subsequent An did not collide directly with On as was expected, but rather On blocked by an interaction with tissue left refractory by An. Because On was blocked, no reentry occurred when pacing ended.     

Impact of Changing Activation Sequence on Bipolar Electrogram Amplitude for Voltage Mapping of Left Ventricular Infarcts Causing Ventricular Tachycardia

Introduction: Wavefront direction is a determinant of bipolar electrogram amplitude that could influence identification of low amplitude regions indicating infarction or scar.Methods: To assess the importance of activation sequence on electrogram amplitude 11 patients with prior infarction and ventricular tachycardia were studied. At 819 left ventricular sites bipolar electrograms were recorded during atrial pacing and ventricular pacing, followed by unipolar pacing with a stimulus of 10 mA at 2 ms. Sites with a pacing threshold > 10 mA were designated electrically unexcitable scar.Results: Areas of low voltage (1.5 mV) were present in all patients. Atrial paced and ventricular paced electrogram amplitudes were strongly correlated (r = 0.77; P < 0.0001). Changing the activation sequence (from atrial pacing to ventricular pacing) produced a > 50% change in electrogram amplitude at 28% of sites and a > 100% change at 10% of sites, but only 8% of sites had an electrogram amplitude classified as abnormal (1.5 mV) with one activation sequence and normal (> 1.5 mV) with the other activation sequence. Electrically unexcitable scar (6% of sites) was associated with lower electrogram amplitude but could not be reliably identified based on electrogram amplitude alone for either activation sequence.Conclusion: Voltage maps created with bipolar recordings using these methods should be relatively robust depictions of abnormal ventricular regions despite variable catheter orientation and activation sequences that might be produced by different rhythms.     

An interactive graphical system for automated mapping and display of cardiac rhythms.

Electrical cardiac mapping has been used to study the mechanisms of cardiac arrhythmias, to assist in clinical diagnosis of rhythm disorders, to guide interventional procedures, or to evaluate the effects of antiarrhythmic drugs. Manual determination of local activation times, the first step in constructing activation maps, is a time-consuming process that precludes the possibility of on-line interactive mapping during an electrophysiologic experiment or a clinical procedure. This report describes an interactive graphic user interface application that (1) automatically determines the activation sequences with good accuracy, (2) displays graphical presentations of activation maps within seconds, and (3) allows manual interactive adjustments. Five automated activation time detection algorithms, one for bipolar electrograms and four for unipolar electrograms, were evaluated and compared. High-density canine recordings were used to evaluate the accuracy of the system. Data included normal atrial activation (sinus rhythm) and abnormal reentrant atrial activation (atrial flutter).     

Electrophysiologic Characteristics and Radiofrequency Catheter Ablation in Patients with Clockwise Atrial Flutter

RF Catheter Ablation of Clockwise Atrial Flutter. introduction: Although the mechanism and radiofrequency catheter ablation of counterclockwise (typical) atrial flutter have been studied extensively, information about the electrocardiographic and electropbysiologic characteristics and effects of radiofrequency ablation in patients with clockwise atrial flutter is limited. Methods and Results: Thirty consecutive patients with clinically documented paroxysmal clockwise atrial flutter were studied. Endocardial recordings and entrainment study using a “halo” catheter with 10 electrode pairs in the right atrium were performed. Radiofrequency energy was applied to the inferior vena cava-tricuspid annulus (IVC-TA) and/or coronary sinus ostium-tricuspid annulus (CSO-TA) isthmus to evaluate the effects of linear catheter ablation. Eighteen patients had both counterclockwise and clockwise atrial flutters, and 12 patients had only clockwise atrial flutter. Both forms of atrial flutter had similar flutter cycle lengths (232 ± 30 vs 226 ± 25 msec, P = 0.526) but reverse activation sequences. Right atrial pacing at a cycle length 20 msec shorter than the flutter cycle length from the CSO-TA isthmus, IVC-TA isthmus, and the area between the two isthmuses revealed concealed entrainment with stimulus-to-P wave intervals of 32 ± 19, 95 ± 14, and 50 ± 17 msec (P = 0.022) in the counterclockwise form, and 110 ± 12, 40 ± 20, and 60 ± 15 msec (P = 0.018) in the clockwise form. In clockwise atrial flutter, 20 patients with biphasic P waves in the inferior leads had the presumed exit site of slow conduction area located at the low posterolateral right atrium; 10 patients with positive P waves in the inferior leads had the presumed exit site located at the mid-high posterolateral right atrium. Among the 18 patients with both forms of atrial flutter, linear ablation lesions directed at the IVC-TA isthmus eliminated both forms of atrial flutter in 14 patients; in the remaining 4 patients. CSO-TA linear lesions eliminated the counterclockwise form and IVC-TA lesions eliminated the clockwise form. Among the 12 patients with the clockwise form only, CSO-TA linear lesions eliminated flutter in 2 and IVC-TA linear lesions eliminated flutter in 10 patients. Successful ablation was confirmed by creation of bidirectional conduction block in the IVC-TA and/or CSO-TA isthmus during pacing from the proximal coronary sinus and right posterolateral atrium sandwiching the linear lesions. During the follow-up period of 17 ± 8 months, 2 patients had recurrence of clockwise atrial flutter, 1 patient had new onset of atypical atrial flutter, and 2 patients had new onset of atrial fibrillation. Conclusions: Counterclockwise and clockwise atrial flutters may have overlapping slow conduction areas with different exit sites. Radiofrequency catheter ablation using the linear method directed at the IVC-TA and CSO-TA isthmuses was feasible and effective in treating both forms of atrial flutter.     

Suppression of Intra‐atrial Reentrant Tachycardia in Patients with Atrial Overdrive Pacing

Background. Intra‐atrial reentrant tachycardia (IART) is a common arrhythmia in adult patients with palliated congenital heart disease (CHD). Traditional treatment methods such as antiarrhythmic drugs (AADs) or radiofrequency ablation are often unsuccessful or cause side effects. These patients often require frequent cardioversion and anticoagulation. The purpose of this study is to evaluate the success of overdrive atrial pacing for the suppression of IART in CHD. Methods. Single center, investigational review board approved, retrospective review of nine patients with CHD and documented, recurrent IART. Patients served as their own historical controls for this study. Phase I was defined as the period 2 years prior to atrial pacing intervention, and Phase II was defined as ≥13 months with atrial pacing; enabled or implanted rate responsive or dynamic overdrive A pacing. During Phase II, the patients' rhythm was monitored by either symptom reporting, ECG, Holter monitoring or pacer diagnostics every 2 months. Results. Cardioversion post A pacing decreased: from 25 to 3, P < .003, patients requiring cardioversions 9 to 1, P < .001, no. AADs 18 to 7, P < .02. Conclusions. Overdrive atrial pacing, ≥70 ppm, is a viable treatment option to suppress recurrent IART. With the suppression of IART, the need for cardioversion, and AAD can be significantly reduced.     

Catheter ablation of arrhythmias in ebstein's anomaly: a multicenter study

Catheter Ablation in Ebstein's Anomaly. Introduction: In patients with Ebstein's anomaly (EA) arrhythmias are frequently encountered. Although most arrhythmias can be targeted with catheter ablation, specific issues render the procedure more challenging in EA. This study examines the mechanisms of the different arrhythmias related to EA and the outcome after catheter ablation. Methods And Results: Clinical and procedural data of catheter ablation in patients with EA in 4 European centers were analyzed. In 32 patients (mean age 24 ± 15 years), 34 accessory pathways (APs), 8 intra‐atrial reentry tachycardias (IART), 5 cavotricuspid isthmus‐dependent atrial flutter (CTI‐AFL), 2 focal atrial tachycardias, and 1 atrioventricular nodal reentry tachycardia were ablated. In 11 patients (34%), multiple ablation targets were present. Eighteen patients (56%) required multiple procedures either for repeat ablation of the same arrhythmia (n = 12), ablation of a different arrhythmia (n = 4), or both re‐ablation of the same and of a different arrhythmia (n = 2). Procedural success rate after first ablation was 80% for APs and CTI‐AFL ablation, and 100% for IART ablation. Redo procedures were necessary in 40% of the patients after ablation of an APs, and in 60% after CTI‐AFL ablation, but in none of the patient with IART ablation. Conclusion: Most arrhythmias related to EA are amenable to catheter ablation. However, ablation procedures are challenging and the need for repeat procedure is particularly high, because some patients have multiple ablation targets and because of technical issues in relation with the dysplastic tricuspid annulus. In addition, several patients develop other arrhythmia mechanisms following ablation . (J Cardiovasc Electrophysiol, Vol. 22, pp. 1391‐1396, December 2011)     

Electroanatomical mapping for visualization of atrial activation in patients with incisional atrial tachycardias.

AIMS: Incisional atrial tachycardias in patients following surgery for congenital heart disease are based on complex structural abnormalities in these hearts. The aim of this study was to evaluate the use of the electroanatomical mapping system, CARTO, in consecutive patients with different forms of incisional atrial tachycardia. METHODS AND RESULTS: The electroanatomical mapping system combines electrophysiological and spatial information and allows visualization of atrial activation in a three-dimensional anatomical reconstruction of the atria. Electroanatomical mapping of right atrial activation was performed in 10 patients after surgery for congenital heart disease, surgery for Wolff-Parkinson-White syndrome, or heart transplantation presenting with 13 incisional atrial tachycardias. The three-dimensional mapping allowed a rapid distinction between focal (n=3) and reentrant mechanisms (n=10) and visualization of the activation wavefronts along anatomical and surgically created barriers. Electroanatomical activation maps (mean right atrial activation time 213+/-107 ms) were constructed with 89+/-60 catheter positions during an average mapping time of 48+/-33 min. Reentrant tachycardias propagating through the tricuspid annulus-vena cava inferior isthmus (n=6) or along periatriotomy loops (n=4) were identified in eight patients. Ectopic atrial foci near surgical scars could be localized in three patients. Catheter ablation by creation of a lesion in a critical isthmus of conduction or by targeting the arrhythmogenic focus eliminated 11 of 13 incisional atrial tachycardias. CONCLUSION: Visualization of atrial activation in a three-dimensional reconstruction of the right atrium using the electroanatomical mapping system CARTO facilitates understanding of the mechanism and defines the reentrant circuits of incisional atrial tachycardias. This new method may improve the success rate of electrophysiologically guided and anatomically guided catheter ablation of incisional atrial tachycardias.     

儿童室间隔修补术后远期心房内折返性心动过速的消融

目的报道儿童先天性心脏病室间隔缺损（VSD）术后远期出现的心房内折返性心动过速（IART）的电生理标测及导管消融疗效。方法8例患儿（男、女各4例）,平均年龄（7．1±4．1）岁,VSD术后1～5年发生持续性IART,8例均有左心室扩大,其中5例合并慢性心力衰竭。行心房电生理标测,部分应用三维标测（EnSiteNavX）技术,标测折返环的关键峡部并行导管消融。结果8例均自发IART,折返环关键部位分布：6例位于三尖瓣环峡部,1例于右心房界嵴至下腔静脉间,1例于三尖瓣环9点位置至界嵴问。所有（100％）患儿手术即刻成功,无并发症。平均随访（25．2±16．5）个月,2例复发,其中1例再次消融成功,总成功率7／8（87．5％）。左心室人小及射血分数均明显好转。结论儿童VSD术后IART机制多为三尖瓣环一下腔静脉峡部依赖型心房扑动,可经导管消融治愈或明显改善。三维标测技术能准确快速定位折返环的电生理峡部并指导消融,显著减少曝光时间。     

Localization of arrhythmogenic triggers of atrial fibrillation

INTRODUCTION: Mapping procedures to identify triggers of atrial fibrillation from pulmonary veins (PVs) are not well established. We sought to determine the value of multipolar recordings from the coronary sinus (CS) and crista terminalis (CT) for identifying the origin of paced and atrial premature depolarizations (APDs) initiating atrial fibrillation from left versus right PVs. METHODS AND RESULTS: Fifteen patients with paroxysmal atrial fibrillation refractory to medications had decapolar catheters (5-mm electrode, 2-mm interelectrode spacing) placed in the CS and posterior medial to the CT. Bipolar electrograms were recorded at each site. Electroanatomic left atrial endocardial maps were created in sinus rhythm, and each PV was identified and paced. During spontaneous APDs initiating atrial fibrillation and PV pace maps, the atrial activation and the earliest electrogram at CS and CT were compared. PV sites were designated as sites of origin of APDs when (1) intracardiac electrograms in the CS and CT during arrhythmogenic APDs matched those of PV pace maps, (2) local activation preceded CS and CT recordings by at least 40 msec (all sites), and (3) atrial depolarizations were eliminated by application of radiofrequency energy (24/26 sites). Pacing from each of the 30 right PV sites resulted in proximal to distal CS activation and later recordings at the CS than the CT (earliest CS-CT activation range: -15 to -58 msec, mean -32 +/- 12). In contrast, pacing from the left PV sites typically (28/30 sites) activated the CS from the distal to proximal poles and demonstrated simultaneous or earlier (CS-CT range: -14 to +54 msec, mean 13 +/- 17) recordings of the CS than the CT (P < 0.0001). For 13 APDs mapped to the right PVs, CS minus CT activation was -17 to -49 msec (mean -31 +/- 8). For 13 APDs localized to the left PVs, the CS minus CT activation time ranged from -8 to +28 msec (mean 14 +/- 15). CONCLUSION: Activation sequence mapping from multipolar catheters placed in the CS and along the posterior medial CT rapidly differentiates right and left PV sites of origin of atrial depolarization.     

Anticoagulation practices in adults with congenital heart disease and atrial arrhythmias in Switzerland

Background: In adults with congenital heart disease (CHD) and atrial arrhythmias, recommendations for thromboprophylaxis are vague and evidence is lacking. We aimed to identify factors that influence decision-making in daily practice.
Methods: From the Swiss Adult Congenital HEart disease Registry (SACHER) we identified 241 patients with either atrial fibrillation (Afib) or atrial flutter/intraatrial reentrant tachycardia (Aflut/ IART). The mode of anticoagulation was reviewed. Logistic regression models were used to assess factors that were associated with oral anticoagulation therapy.
Results: Compared with patients with Aflut/IART, patients with Afib were older (51 ± 16.1 vs 37 ± 16 years, P < .001) and had a higher CHA₂DS₂-VASc (P < .001) and HAS-BLED scores (P = .005). Patients with Afib were more likely on oral anticoagulation than patients with Aflut/IART (67% vs 43%, P < .001). In a multivariate logistic regression model, age [odds ratio (OR) 1.03 per year, 95%CI (1.01-1.05), P = .019], atrial fibrillation [OR 2.75, 95%CI (1.30-5.08), P = .007], nonparoxysmal atrial arrhythmias [OR 5.33, 95%CI (2.21-12.85)], CHA2DS2-VASc-Score >1 [OR 2.93, 95%CI (1.87-4.61), P < .001], and Fontan palliation [OR 17.5, 95%CI (5.57-54.97), P < .001] were independently associated with oral anticoagulation treatment, whereas a HAS-BLED score >1 was associated with absence of thromboprophylaxis [OR 0.32, 95%CI (0.17-0.60), P < .001].
Conclusions: In this multicenter study, age, type, and duration of atrial arrhythmias, CHA2DS2- VASc and HAS-BLED scores as well as a Fontan palliation had an impact on the use of thromboprophylaxis in adult CHD patients with atrial arrhythmias. In daily practice, anticoagulation strategies differ between patients with Afib and those with Aflut/IART. Prospective observational studies are necessary to clarify whether this attitude is justified.     

Atrial flutter in the young: a collaborative study of 380 cases

As children with cardiac disease grow older, atrial flutter becomes more prevalent. A collaborative study was performed in 19 institutions to determine the clinical characteristics of these children and the factors affecting prognosis. There were 380 patients with one or more electrocardiographically documented episodes of atrial flutter that first occurred between ages 1 and 25 years (mean age at onset 10.3). Episodes of flutter continued to occur for a mean of 2.5 years after the onset. Of the 380 patients, 60% had repaired congenital heart disease, 13% palliated congenital heart disease, 8% unoperated congenital heart disease, 8% an otherwise normal heart, 6% cardiomyopathy, 4% rheumatic heart disease and 2% other lesions. Overall, drugs were effective in eliminating atrial flutter in 58% of patients; specifically, amiodarone and digoxin plus quinidine were effective in 53%, digoxin alone in 44% and propranolol in 21%. Amiodarone was effective in seven (78%) of nine patients. Corrective surgery was performed after the onset of atrial flutter in 66 patients; in 52% the atrial flutter was easier to control or it resolved and in only 4% it was worse. At follow-up (mean 6.5 years), 83% of the patients were alive (49% without atrial flutter and 34% with atrial flutter) and 17% died (10% suddenly, 6% of nonsudden cardiac cause and 1% of noncardiac cause). Cardiac death occurred in 20% of those for whom an effective drug could not be found to eliminate atrial flutter compared with 5% of those who were treated with an effective drug (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Successful intracardiac electrical conversion of atrial flutter in patients with complex congenital heart disease

Sixteen patients presenting on 21 occasions with atrial flutter in association with complex congenital heart disease were treated by intracardiac stimulation techniques combined with activation mapping. Nineteen episodes of atrial flutter were successfully converted to sinus rhythm. In the remaining two episodes atrial fibrillation was induced with spontaneous conversion to sinus rhythm within 12 hours in one episode and immediate DC cardioversion to sinus rhythm in the other. Intracardiac stimulation techniques were highly successful in this group and allowed reliable conversion to sinus rhythm without general anaesthesia and high energy cardioversion. In patients with atrial flutter associated with congenital heart disease intracardiac stimulation techniques should be tried first.