Sotalol for Atrial Tachycardias After Surgery for Congenital Heart Disease

Atrial tachycardias, in particular atrial flutter after surgery for congenital heart disease, is associated with a high mortality. Treatment with various antiarrhythmic drugs and/or antitachycardia pacemakers is not very successful. Sotalol, a Class III drug, has shown to be a promising drug in adults with atrial tachycardias. However, the experience with sotalol in children after surgery for congenital heart disease is limited. Therefore, we describe our results here. Between December 1990 and February 1997, 26 children with atrial tachycardias, most of them with atrial flutter or fibrillation (n = 20), after surgery for congenital heart disease were treated with sotalol orally. The age of the children at the start of treatment was 7.5 ± 5.8 years (mean ± SD). The time interval between surgery and the start of atrial tachycardia ranged from 1 day to 14.3 years (3.8 ± 3.8 years). Conversion to sinus rhythm was achieved in 16 out of 22 hemodynamically stable children with a dosage of 4.0 ±1.6 mg/kg per day. The six children without sinus rhythm on sotalol and four hemodynamically unstable patients were treated prophylactically with sotalol after DC cardioversion for their tachycardias. Two children complained of mild transient fatigue. Heart rate decreased during therapy (95 ± 33 vs 81 ± 21 beats/min; P = 0.01). QT_c-intervals did not change. Proarrhythmias such as torsades de pointes were not encountered. Two children with a preexis-tent sick sinus syndrome showed aggravation of bradycardia and needed pacemaker implantation. The percentage of children with a recurrence-free interval of 1 and 2 years was 96% and 81 %, respectively, for all atrial tachycardias, and 92% and 66% for atrial flutter. The recurrences of atrial tachycardias during the follow-up period, which ranged from 0.1-6.1 years (2.5 ± 1.8 years) could be treated with only an increase of the dosage of sotalol in all but one patient. We conclude that sotalol is an effective drug for the treatment and prevention of atrial tachycardia in children afler surgery for congenital heart disease.     

Radiofrequency Ablation of Intraatrial Reentrant Tachycardia after Surgery for Congenital Heart Disease

Intraatrial reentry tachycardia is a common cause of both morbidity and mortality after surgery for a variety of congenital heart defects. Despite an armamentarium of arrhythmia management tools, including drug therapy, antibradycardia, and antitachycardia pacing, and catheter ablation, management of these arrhythmias remains a challenge. This report briefly reviews the problem, assesses the current successes and failures of radiofrequency catheter ablation for treating it, and discusses a number of ongoing developments that may improve both early and late outcome.     

Single Catheter Determination of Local Electrogram Prematurity Using Simultaneous Unipolar and Bipolar Recordings to Replace the Surface ECG as a Timing Reference

DELACRETAZ, E., et al. : Single Catheter Determination of Local Electrogram Prematurity Using Simultaneous Unipolar and Bipolar Recordings to Replace the Surface ECG as a Timing Reference. Bipolar recordings eliminate much of the far-field signal, while minimally filtered unipolar recordings contain substantial far-field signal components. These properties may allow the onset of the unipolar recording to serve as a timing reference for the bipolar recording obtained from the same electrode catheter during mapping of focal atrial or ventricular tachycardias. Mapping and RF ablation were performed in 26 patients with focal ventricular tachycardia and 14 patients with focal atrial tachycardia. At 205 mapping sites, simultaneous recordings of (1) minimally filtered unipolar electrograms (0.5–500 Hz), (2) high pass filtered unipolar electrograms (100 Hz), and (3) filtered bipolar recordings (30–500Hz) were analyzed. The interval between the onset of the minimally filtered unipolar electrogram and the first peak of the bipolar electrogram (Uni_On - Bi_p) correlated closely with the timing of the local electrogram referenced to the surface ECG (  r = 0.85, P < 0.001  ). Of 53 sites where RF ablation was performed, Uni_On - Bi_P was shorter at successful compared to unsuccessful sites (  3.8 ± 3.5 vs 9.2 ± 5.2ms, P < 0.001  ) and was < 15 ms at all successful sites. In conclusion, the comparison of simultaneous unipolar and bipolar electrograms from a single catheter allows assessment of the prematurity of local electrograms from a focal source without the use of the P wave or QRS onset as a timing reference.     

The Role of Concomitant Arrhythmia Surgery in Patients Undergoing Repair of Congenital Heart Disease

Long-term survival after repair of complex congenital heart lesions is associated with the late development of arrhythmias as well as residual hemodynamic abnormalities. Understanding arrhythmias as electromechanical problems provides the basis for surgical intervention to correct the arrhythmia as well as anatomical disturbances. Operative techniques are highly effective in treating atrial reentry tachycardia and atrial fibrillation. Surgery for ventricular tachycardia is less effective: the arrhythmia may be reduced by improving hemodynamics, but a defibrillator may be required. Integration of device therapy into surgery may improve outcomes by preventing bradycardia as a precursor to tachycardia, and optimizing ventricular synchrony.     

Different Mechanisms Underlying Consecutive, Postoperative Atrial TachyArrhythmias in a Fontan Patient

Introduction: Atrial tachyarrhythmias (AT) frequently develop later after a Fontan operation and can be successfully treated by ablative therapy. However, new arrhythmias often develop.
Methods and Results: Consecutive AT emerging in a Fontan patient were ablated using three-dimensional electro-anatomical mapping. During a 6-year period, nine different AT were ablated, including intraatrial reentrant AT (N = 5), focal AT (N = 3), and focal atrial fibrillation (N = 1) originating from distinct right atrial sites.
Conclusion: In a Fontan patient, successive AT can be caused by different mechanisms. These AT are most likely the result of progressive atrial cardiomyopathy and can be treated by catheter ablation.     

Subthreshold Stimulation at the Focal Origin of Para-Hisian-Located Ectopic Atrial Tachycardia

WEISS, C., et al. : Subthreshold Stimulation at the Focal Origin of Para-Hisian-Located Ectopic Atrial Tachycardia. The focal origin of ectopic atrial tachycardia (EAT) is occasionally located in the superoparaseptal region adjacent to the bundle of HIS. Radiofrequency catheter ablation (RFCA) of EAT in this anatomic location implies the potential hazard of adverse impairment of the AV conduction. Therefore, careful precise mapping is mandatory. Subthreshold stimulation as defined as the delivery of noncaptured low energy pulses has been introduced as an additional mapping technique for slow pathway ablation in the setting of AV nodal reentrant tachycardia and other reentrant tachycardia. A patient with a right superoparaseptal EAT focus, in which subthreshold stimulation (STS) could determine the site of successful subsequent RFCA is described. During STS with EAT termination no AV conduction disturbances, junction-escape rhythms or atrial capture could be recorded. Thus STS may be used as an additional mapping tool to identify successful ablation sites in EAT.     

左向右分流先天性心脏病双室相互作用的评估

４例左向右分流先心病患儿，用导管法检测阻力比率（ＲＲ），导纳法检测左、右心室收缩时间间期比率（Ｒ／Ｌ）及等容舒张时间比率（ＹＯＩ／ＸＯＩ）。结果证明Ｒ／Ｌ，ＹＯＩ／ＸＯＩ均参与双室活动协调性调节，ＲＲ是反映左向右分流先心病双室舒缩功能相互作用的有效指标。     

不同麻醉药物在小儿先天性心脏病介入治疗中的应用比较

【目的】观察丙泊酚复合右美托咪定和丙泊酚复合氯胺酮静脉全麻对行先天性心脏病导管封堵术患儿术中血流动力学和术后麻醉恢复时间的影响。【方法】将行先天性心脏病导管封堵术患儿72例,随机分为丙泊酚复合右关托咪定静脉全麻组（A组）和丙泊酚复合氯胺酮静脉全麻（B组）,每组各36例。患儿术前均给予阿托品0．01mg／kg,A组患儿静脉注射丙泊酚1．5mg／kg,缓慢注射右美托咪定1．Omg／kg,输注时间超过10min,以诱导麻醉,继以右美托咪定0．5μg／（kg·h）和丙泊酚4～6mg／（kg·h）持续泵入维持,B组丙泊酚用法同A组,诱导时复合使用氯胺酮1．0mg／kg,继以0．5μg／（kg·h）维持。术中常规监测血压、心率、呼吸频率、呼吸幅度、血氧饱和度和心电图变化,以改良Steward苏醒评分评估患儿术后麻醉恢复时间。【结果】两组在心内操作时心率均较麻醉诱导前显著增加（均P〈0．01）,但B组较A组更为明显（P〈0．05）。B组麻醉恢复时间显著长于A组,差异有统计学意义（P〈0．01）。【结论】丙泊酚复合右美托咪定静脉全麻下行小儿先天性心脏病介入治疗对操作过程中的心率影响更小,麻醉恢复更快。     

Benefits and Potential Risks of Atrial Antitachycardia Pacing After Repair of Congenital Heart Disease

Atrial reentry tachycardia is common after surgical repair of congenital heart disease. The arrhythmia is often difficult to treat and is occasionally life-threatening. This study reports experience with atrial antitachycardia (AAIT mode) pacing for the management of atrial reentry tachycardia, with emphasis on the risks and benefits of automatic pacing therapy. Eighteen patients (2–32 years of age) with a variety of congenital heart lesions underwent atrial antitachycardia pacemaker placement for recurrent atrial tachycardia that was amenable to pace termination prior to the implantation procedure. An appropriate antitachycardia program was determined by repeated induction and termination of atrial tachycardia using the noninvasive programmed stimulation mode of the pacemaker. Over 4–30 months of follow-up, 6 patients had 189 episodes of tachycardia successfully converted with AAI-T pacing, 4 patients had 8 episodes of tachycardia detected hut not successfully converted, and 8 patients had no episodes of tachycardia with antibradycardia pacing alone. The number of patients receiving pharmacological therapy other than digoxin or beta blockade fell from 12 to 6, Two subjects died suddenly, 1 while wearing a Holter monitor. In both, tachycardia was detected and pace cardioversion attempted. Conclusions: Atrial antitachyardia pacing is a useful tool in the management of patients with congenital heart disease and atrial arrhythmias; however, in selected cases, it may not prevent and may even exacerbate the lethal complications of the tachycardia. Antitachycardia function evaluation is recommended under varying levels of autonomic stress prior to institution of automatic therapy.     

Atrial Arrhythmias During Chronic Follow-Up of Surgery for Complex Congenital Heart Disease

After surgery for complex congenital heart disease, clinically important atrial tachyarrhythmias have a higher than normal incidence if sufficiently large regions of conduction block occur within the atria, especially in the presence of hemodynamic alterations. Sinus bradycardia may result from direct damage to the sinus node and its blood supply. Historical data have identified patients who have undergone the Mustard or Senning operations for dextrotransposition of the great vessels and the Fontan operation in cases of functional single ventricle as being at great risk for atrial tachyarrhythmias. These arrhythmias are especially poorly tolerated when there are co-existing hemodynamic alterations and are an important source of morbidity and mortality. Until recently, treatment strategies have been limited to antiarrhythmic drugs, bradycardia pacing, and—in suitable patients—antitachycardia pacing, often in combination. Amiodarone has been the most efficacious drug, but has only been of moderate value because of extracardiac side effects. Radiofrequency ablation of the atrial regions critical to reentrant circuits, which was discovered to be of value in patients with atrial flutter and a normal heart is being applied to this diverse group of patients. Early results are promising, but the Fontan operation patients are especially challenging because of early recurrences of apparently new reentrant circuits. Progress in this area will likely come from newer surgical techniques that prevent the milieu for atrial reentry and from multidimensional mapping systems for our current patients.     

新生儿先天性心脏病的根治与围手术期治疗

[目的]分析本院外科手术治疗的36例新生儿先天性心脏病婴儿的临床资料,总结新生儿先心病的围手术期处理经验.[方法]全组患儿均在体外循环下行一期根治术,术前给予控制感染、纠正心衰、增加心功能储备等处理,术后给予呼吸、循环管理,治疗并发症等处理.[结果]①21例未出现并发症,术后(11.91±3.65)d痊愈出院.12人出现并发症,共32例次,均痊愈出院.死亡3例,病死率8.33%.均为复杂性先心病患儿,死于重度低心排综合征.②比较患儿入院、出院时呼吸频率、心率、肝脏大小,结果均有显著统计学意义(P＜0.05).③分析患儿术前、术后10 d所做心脏彩超数据,结果表明:射血分数、舒张末期左室内径、每分钟心输出量、舒张末期左室容积均无明显差异(P＞0.05),合并肺动脉高压患儿出院时平均肺动脉压、肺动脉内径较术前明显下降(P＜0.05).[结论]先天性心脏病手术宜早期进行.合理的围手术期治疗,是提高新生儿先心病手术成功率的关键.     

左向右分流型先天性心脏病患儿潮气呼吸肺功能的改变

【目的】探讨左向右分流型先天性心脏病（简称先心病）患儿肺功能的改变。【方法】收集于2006年1月至2008年12月在本院住院行手术治疗的52例左向右分流型先心病患儿为先心病组,同时设置健康对照组50例。健康对照组与先心病组分别进行潮气呼吸肺功能测定。【结果】先心病组患儿潮气呼吸肺功能与健康对照组相比,每分通气量（MV）差异无显著性（P〉0．05）,呼吸频率（RR）增快,潮气量（VT／Kg）减小（P〈O．05）;吸气时间（TI）及呼吸比（TI／TE）缩短（P〈0．05）;达峰时间（TPEF）、达峰时间比（TPEF／TE）、达峰容积（VPEF）及达峰容积比（VPEF／VE）均明显降低（P〈0．05）;潮气呼气峰流速（PTEF）增快（P〈0．05）,潮气量时呼气流速（TEF25％）减低（P〈0．05）,而TEF75％、TEF50％差异无显著性（P〉0．05）。【结论】左向右分流型先心病可影响肺功能,引起限制性及阻塞性通气障碍。     

双源计算机断层摄影对先天性心脏病的诊断

  目的  探讨双源计算机断层摄影(dual-source computed tomography, DSCT)诊断先天性心脏病(先心病)的临床应用价值。  方法  DSCT增强扫描检查先心病患者20例, 年龄4个月~53岁, 平均19岁; 所有病例均以心脏超声(echocardiography, ECHO)为对照, 并经手术证实。  结果  20例患者经手术证实的心内外结构畸形共63处, DSCT检出59处, 诊断敏感性为93.7%;ECHO检出55处, 诊断敏感性87.3%, 两种方法诊断敏感性比较差异无统计学意义(χ²=1.474, P=0.225)。63处结构畸形中, 心脏部分畸形41处, DSCT检出37处(90.2%), ECHO检出37处(90.2%), 两者敏感性相当(P=1.000);心脏-大血管连接处畸形9处, DSCT检出9处(100%), ECHO检出8处(88.9%), 差异无统计学意义(P > 0.05);大血管部分畸形13处, DSCT检出13处(100%), ECHO检出10处(76.9%), 差异无统计学意义(P > 0.05)。  结论  DSCT能够显示心内外结构畸形, 具有较高的诊断敏感性, 对先天性心脏病, 特别是合并心外大血管畸形的诊断有重要价值。     

Radiofrequency Catheter Ablation of Atrial Tachycardia with Unusual Left Atrial Sites of Origin: Report of Two Cases

Two cases of successful radiofrequency catheter ablation of adult-onset atrial tachycardia originating from the left atrium adjacent to the mitral annulus are presented. Endocardial catheter activation mapping performed by retrograde or atrial transseptal approach revealed presystolic activation at the successful ablation site in both patients, and fractionation during sinus rhythm and tachycardia in one. The 12 lead electrocardiogrnphic P wave appearance was suggestive of a left atrial tachycardia origin in both cases.     

Importance of Tachycardia Cycle Length for Differentiating Typical Atrial Flutter from Scar‐Related in Adult Congenital Heart Disease

Background: Radiofrequency catheter ablation (RFCA) for intraatrial reentrant tachycardia (IART) in congenital heart disease (CHD) remains difficult. Methods: Thirty‐four consecutive adult patients (age, 37.6 ± 12.8 years; male, 21) with previously repaired CHD and IART underwent an electrophysiological study and RFCA. CHD included atrial septal defect (ASD, n = 14), tetralogy of Fallot (n = 11), ventricular septal defect (n = 4), pulmonary atresia (n = 2), atrioventricular septal defect (n = 1), transposition of the great arteries (n = 1), and double‐outlet right ventricle (n = 1). Results: Duration of CHD repair to IART onset was 19.1 ± 8.5 years. Thirty and four patients had single‐ and double‐loop reentrant tachycardia, respectively. Among the total of 38 IARTs, which were mapped, 22 (57.9%) and 13 (34.2%) IARTs were cavotricuspid isthmus (CTI)‐dependent atrial flutter (AFL) and scar‐related AFL, respectively. Typical AFL electrocardiography findings including definite sawtooth appearance in inferior leads and positive F wave in lead V1 were observed in only 12 of 21 patients (57.1%) with CTI‐dependent AFL. CTI‐dependent AFL had a significantly longer tachycardia cycle length (TCL) than scar‐related AFL (267.6 ± 34.4 ms and 235.9 ± 37.0 ms, respectively; P = 0.031). TCL > 250 ms had 79% sensitivity as the cutoff value for differentiating CTI‐dependent from scar‐related AFL. The acute success rates of RFCA in CTI‐dependent and scar‐related AFLs were 85.7% and 90.0%, respectively. The recurrence rates in CTI‐dependent and scar‐related AFLs were 11.1% and 11.1%, respectively, during a follow‐up of 21.2 ± 28.3 months. Conclusions: CTI‐dependent AFL was the most common IART in adult patients with repaired CHD and was easily manageable by RFCA. TCL might help to differentiate CTI‐dependent AFL from other IARTs. (PACE 2012;35:1338–1347)     

Basket catheter localization of the origin of atrial tachycardia with atypical morphology after atrial flutter ablation

Atrial activation from a site in the low lateral right atrium will typically proceed in a superior direction. We present a case of a low lateral right atrial tachycardia with a surface electrocardiographic P wave morphology that appeared to have an inferiorly directed axis. The tachycardia occurred 2 years after successful atrial flutter ablation. The use of a multipolar basket catheter allowed confirmation of the focal origin of the tachycardia, permitted its rapid localization, facilitated catheter ablation, and provided clues to atrial activation that helped describe the appearance of the P wave.     

Effect of Pacing Site on the Atrial Electrogram at Target Sites for Slow Pathway Ablation in Patients with Atrioventricular Nodal Reentrant Tachycardia

Atrial electrograms recorded from target sites during radiofrequency catheter ablation of the slow atrioventricular (AV) nodal pathway are often fractionated and may be associated with a late, high frequency component (the slow pathway potential). The purpose of the current study was to assess the effects of slow pathway ablation on the morphology of the atrial electrogram and to determine whether target site electrograms display direction dependent changes in morphology during atrial pacing maneuvers. Twenty-six patients with typical AV nodal reentry had electrograms recorded from target sites before and after successful ablation of the slow A V nodal path way and during pacing from the high right atrium and distal coronary sin us at cycle lengths of 500 and 300 msec. There was no significant change in the duration or degree of fractionation of the atrial electrogram as the result of slow pathway ablation. In contrast, the duration and degree of fractionation were less when pacing from the coronary sinus compared with sinus rhythms or right atrial pacing. Pacing rate did not affect electrogram morphology. These data suggest that the morphology of the slow pathway target site electrogram is dependent on the direction of atrial activation and that the "slow pathway potential" does not represent activation of an anatomically discrete pathway.