Recipient to Donor Conduction of Atrial Tachycardia Following Orthotopic Heart Transplantation

We report a case of atrial tachycardia in a 60-year-old male 8 years postorthotopic heart transplantation. At electrophysiology study, the clinical rhythm was found to arise from the remnant of the recipient atrium and was successfully terminated by delivery of radiofrequencv energy. Surgical scars formed at the anastomosis of the recipient and donor atrium during the time of orthotopic heart transplantation are thought to electrically isolate the two areas. Although rarely recognized, dysrhythmias originating from the recipient atrial remnant may occur more often than previously thought.     

Atrial Tachycardia Successfully Treated by Electrical Isolation of the Superior Vena Cava

GERSTENFELD, E.P., et al .: Atrial Tachycardia Successfully Treated by Electrical Isolation of the Superior Vena Cava. This case report describes a patient with an atrial tachycardia that was difficult to induce and that originated from the superior vena cava. Although the patient had frequent episodes of tachycardia, the tachycardia induced in the electrophysiological laboratory was nonsustained and could not be adequately localized for focal ablation. A circumferential mapping catheter was used to guide electrical isolation of the superior vena cava from the right atrium, curing the tachycardia. Electroanatomic mapping and intracardiac echocardiography were used to monitor the ablation and document patency of the superior vena cava throughout the ablation. (PACE 2003; 26[Pt. I]:906–910)     

Superior Vena Cava Stenosis after Radiofrequency Catheter Ablation for Electrical Isolation of the Superior Vena Cava

Ectopic beats originating from the superior vena cava (SVC) may initiate atrial fibrillation. This report describes a patient undergoing radiofrequency catheter ablation for electrical isolation of the SVC resulting in SVC stenosis. Noncircumferential lesion sets for SVC isolation to reduce ablation times may be preferred. (PACE 2010; e36–e38)     

Radiofrequency Catheter Ablation for AV Nodal Reentrant Tachycardia Associated with Persistent Left Superior Vena Cava

Slow A V nodal pathway ablation using RF is highly effective for patients with refractory A V nodal reentrant tachycardia (AVNRT). We report three catheter ablation cases using RF current in patients associated with persistent left superior vena cava (PLSVC). Three patients with drug refractory AVNHT of common variety were involved in this study. An electrode catheter introduced through the left subclavian vein inserted directly into the coronary sinus, a typical anatomical finding of PLSVC. The ablation procedure was initially performed at the posteroinferior region of Koch's triangle. A slow pathway potential could not be found from that area; nonsustained junctional tachycardia (NSJT) did not occur during the delivery of RF current; there was failure to eliminate slow AV nodal pathway conduction. The catheter then was moved into the bed of the proximal portion of the markedly enlarged coronary sinus. A slow AV nodal pathway potential was recorded through the ablation catheter, and the delivery of RF current caused NSJT in two patients. Complete elimination of slow AV nodal pathway conduction was accomplished in these two patients by this method. No adverse effects were provoked by this procedure. Catheter ablation of the slow A V nodal pathway guided by a slow pathway potential and the appearance of NSJT was feasible and safe in the area of the coronary sinus ostium in patients associated with PLSVC.     

Atrioventricular Nodal Tachycardia in a Patient with Anomalous Inferior Vena Cava with Azygos Continuation and Persistent Left Superior Vena Cava

A 39-year-old female patient was referred for ablation of recurrent episodes of atrioventricular nodal reentrant tachycardia. A combination of an anomalous inferior vena cava with azygos continuation and a persistent left superior vena cava was discovered. A nonfluoroscopic navigation system was very useful for catheter ablation of the tachycardia in this unusual case of anomalous venous system of the heart.     

Radiofrequency Catheter Ablation of Parasystole Originating from the Inferior Vena Cava

A 76‐year‐old man with a history of atrial septal defect repair underwent radiofrequency (RF) ablation of typical atrial flutter. During electrophysiological study, incessant sharp potentials were recorded, originating from the ostium of the inferior vena cava (IVC), and dissociated from atrial activity. During sinus rhythm, these potentials propagated to the atria and caused premature complexes when falling beyond the atrial refractory period. Electro‐anatomical mapping revealed the presence of the earliest potential in the postero‐lateral ostium of the IVC, propagating to the septal region. After RF isolation of the IVC, the patient has remained arrhythmia‐free over a 5‐year follow‐up. (PACE 2010; e62–e64)     

Radiofrequency Catheter Ablation of Left Atrial Tachycardia Originating Within the Pulmonary Vein in a Patient with Dextrocardia

A case is presented of a 38-year-old male with dextrocardia in whom radiofrequency current ablation of an incessant atrial tachycardia originating within the infero-lateral pulmonary vein was achieved. Activation mapping with detection of the earliest atrial activation was used for identification of the arrhythmogenic focus. In addition to fluoroscopy, trans- esophageal echocardiography was used for catheter guidance during the transseptal puncture. The present experience suggests that location of an arrhythmogenic focus within the pulmonary venous system should be considered whenever early atrial activation during ectopic atrial tachycardia is recorded at the junction between thfi left atrium and the pulmonary veins.     

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.     

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.     

Idiopathic Ventricular Tachycardia Originating from the Left Ventricle Near the His Bundle

A 62‐year‐old man with idiopathic ventricular tachycardia (VT) exhibiting left bundle branch block and left inferior axis QRS morphology with a Qr in lead III underwent electrophysiological testing. Successful ablation was achieved in the left ventricle (LV) at a site with an excellent pace map, adjacent to the His bundle electrogram recording site. At that site, the sequence of the ventricular electrogram and late potential recorded during sinus rhythm reversed during spontaneous premature ventricular contractions with the same QRS morphology as the VT. This case shows that VT can arise from the LV ostium adjacent to the membranous septum. (PACE 2010; 33:e114–e118)     

前间隔心动过速源于主动脉无冠窦的射频消融

【目的]探讨经主动脉无冠窦途径导管射频消融治愈的前间隔房速、前间隔旁路患者的心电图特点及射频消融治疗情况。【方法】回顾性分析经无冠窦途径导管射频消融治愈的3例前间隔房速和2例前间隔旁路的体表心电图、心内电图以及消融成功时靶点电图等心电生理学特征。【结果】3例局灶性前间隔房速均能被心房刺激反复诱发和终止,其心电图特点：房速时P波间期明显窄于窦律时P波间期,I、aVL导联P渡正向,Ⅱ、Ⅲ和aVF导联P呈负正双向,心房标测提示最早的心房激动在希氏柬区,但主动脉无冠窦内标测的心房激动较希氏束区的心房波提前,解剖定位希氏柬上后方,消融靶点无希氏束电位。2例前间隔旁路心电图示：窦性心律时呈窄ORS波形,未见预激波,心动过速呈窄QRS形,在主动脉无冠窦内记录到最早心房激动点,且无希氏柬电位。5例均在无冠窦消融成功。随访15．2±12．1（2～40）个月,无复发病例。【结论】源于无冠窦的前间隔房速和前间隔旁路具有其相对的心电生理学特征,常规心内膜途径消融困难时应考虑从无冠窭玲径标测消融策略．     

起源于冠状静脉窦口附近的房性心动过速体表心电图特点和射频消融治疗

【目的】阐述起源于冠状静脉窦口附近的房性心动过速（简称房速）体表心电图特点及射频消融结果。【方法】本组共6例起源于冠状静脉窦口的局灶性房速,冠状静脉窦口位置通过冠状静脉窦造影确定。如标测的最早激动点位于冠状静脉窦口周1cm范围以内的区域并在此消融成功,则认为心动过速是起源于冠状窦口的房速。【结果】6例房速均在冠状静脉窦口附近消融成功,靶点局部A波激动时间领先体表P波起点31～50（39±12）ms。本组房速体表P波具有以下特点：Ⅱ、Ⅲ、aVF导联P波呈负向波,Ⅰ导联呈等电位线或低幅正向波,aVL导联呈正向波,多数病例V1导联P波前半部分为等电位线,后半部分为正向波,胸前导联P波由右向左在V3～V5导联逐渐移行为负向。【结论】冠状静脉窦口附近是右房房速的一个重要起源点,其体表心电图有明确特征。     

Atrial Ectopy Originating from the Posteroinferior Atrium During Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia

Atrial ectopy sometimes appears during RF ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT). However, its origin, characteristics, and significance are still unclear. To examine these issues, we analyzed 67 consecutive patients with AVNRT (60 with slow-fast AVNRT and 7 with fast-slow AVNRT), which was successfully eliminated by RF ablation to the sites with a slow potential in 63 patients and with the earliest activations of retrograde slow pathway conduction in 4 patients. During successful RF ablation, junctional ectopy with the activation sequence showing H-A-V at the His-bundle region appeared in 52 patients (group A) and atrial ectopy with negative P waves in the inferior leads preceding the QRS and the activation sequence showing A-H-V at the His-bundle region appeared in 15 patients (group B). Atrial ectopy was associated with (10 patients) or without junctional ectopy (5 patients). Before RF ablation, retrograde slow pathway conduction induced during ventricular burst and/or extrastimulus pacing was more frequently demonstrated in group B than in group A (9/15 [60%] vs 1/52 [2%], P < 0.001). Successful ablation site in group A was distributed between the His-bundle region and coronary sinus ostium, while that in group B was confined mostly to the site anterior to the coronary sinus ostium. In group B, atrial ectopy also appeared in 21% of the unsuccessful RF ablations. In conclusion, atrial ectopy is relatively common during slow pathway ablation and observed in 8% of RF applications overall and 22% of RF applications that successfully eliminated inducible AVNRT. Atrial ectopy appears to be closely related to successful slow pathway ablation among patients with manifest retrograde slow pathway function.     

Electrophysiological Features of Atrial Tachycardia Arising from the Atrioventricular Annulus

MATSUOKA, K., et al. : Electrophysiological Features of Atrial Tachycardia Arising from the Atrioven-tricular Annulus. Atrial tachycardia (AT) arises from various sites in the atrium and the mechanisms are nonuniform. McGuire et al. reported that the cells around the atrioventricular annuli resembled nodal cells in their cellular electrophysiology. The purpose of this study was to delineate the electrophysiological features of AT arising from the atrioventricular (AV) annulus (AVAT). The study included five patients with six AVATs that were abolished by the radiofrequency energy delivery. The location of the AV annuli was defined by using the AV ratio of the local electrograms and the amplitude of the ventricular electrograms, in addition to the anatomic findings under fluoroscopic guidance. The tachycardia cycle lengths were  403 ± 117 ms  . An AV ratio of the electrograms at the successful ablation sites was  0.4 ± 0.4  at the tricuspid annulus and  1.5 ± 0.3  at the mitral annulus. Small doses (  mean 3.2 ± 1.8 mg  ) of adenosine triphosphate could terminate all the tachycardia episodes for five of the ATs without the development of AV nodal conduction block. The successful ablation sites were located at the right mid-septum in 1 AT, right posteroseptum in 2 ATs, right posterolateral region in 1 AT, and left anteroseptum in 2 ATs. These findings suggest that the cells with nodal-type action potentials around both annuli might play an important role in the genesis of AVAT.     

Atrial Tachycardia as a Proarrhythmic Effect of Radiofrequency Catheter Ablation for Atrioventricular Nodal Reentrant Tachycardia

Radiofrequency catheter ablation is now the first line treatment for atrioventricular nodal reentrant tachycardia. The success rate is high with a low incidence of complications. However, a possible proarrhythmic effect of radiofrequency energy has been rarely reported and no study has demonstrated a direct correlation between the anatomic site of the radiofrequency application and the origin of a new post‐ablation arrhythmia. We present a case of a focal atrial tachycardia that occurred after slow pathway radiofrequency catheter ablation for atrial nodal reentrant tachycardia and originating close to the previous ablation site. This tachycardia was successfully treated with a second ablation session. (PACE 2011; 34:e33–e37)     

Lead aVL P‐Wave Polarity: Insight from Mapping and Ablation of Atrial Arrhythmia Initiated from Superior Vena Cava

We report a case of focal atrial tachycardia (AT) originating from prior superior vena cava isolation line. The P‐wave morphology in lead aVL during the AT differed from that during sinus rhythm although their foci were in close proximity to each other. We discuss the mechanism based on the activation maps of the right atrium. (PACE 2010; 33:e100–e101)     

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.     

Atrial Tachycardia Originating from the Atrial Septum in a Patient with Dextrocardia and Complex Structural Heart Disease

We report a case with dextrocardia, corrected transposition of the great arteries. He also had an atrial septum defect (ASD) with patch repair. Activation map showed a centrifugal activation from a focal origin on the systemic lower left atrial ASD patch. Ablation of the origin can terminate the atrial tachycardia. (PACE 2012; 35:e306–e308)