Successful catheter ablation of focal atrial tachycardia from the non-coronary aortic cusp.

We describe a patient with frequent episodes of unusual paroxysmal supraventricular tachycardia. During the electrophysiological examination, the tachycardia was easily induced and terminated by atrial pacing. The earliest activation during right atrial activation mapping was located near the atrioventricular node and the His bundle. However, detailed mapping of the aortic root demonstrated that the local activation in the non-coronary aortic cusp preceded the activation at the His bundle region. Radiofrequency catheter ablation at this site terminated the tachycardia with no complications.     

主动脉无冠窦内射频消融前间隔房室旁路

目的 报道经主动脉无冠窦内射频消融前间隔房室旁路.方法 7例患者,男性4例,女性3例,平均年龄（38.4±14.7）岁.电生理检查证实存在房室旁路,并检查其前传逆传功能和诱发旁路参与的房室折返性心动过速.在心动过速时标测最早心房逆传激动点作为消融靶点.结果 7例心动过速时最早心房激动部位均位于前间隔区域,但经右心房途径反复消融均不能成功阻断旁路,而在无冠窦内可标测到最早逆传心房激动点并消融成功,无并发症出现.结论 主动脉无冠窦内消融可作为治疗前间隔房室旁路的一种新途径,特别适用于右心房前间隔区域消融失败的病例.     

Radiofrequency catheter ablation of both atrial ventricular nodal reentrant and atrial ventricular reentrant tachycardia in a single session

Radiofrequency catheter ablation is a new therapeutic approach to treat patients with symptomatic drug-resistant paroxysmal supraventricular tachycardia. Ablation of two accessory atrioventricular pathways in a single session has been frequently described previously. However, ablation in a single session of both the fast pathway, involved in atrial ventricular nodal reentrant tachycardia, and a concealed atrioventricular accessory pathway involved in a circus movement tachycardia has rarely been reported. A 57-year-old man with a grade III aortic incompetence had the infrequent association of atrial ventricular nodal reentrant tachycardia and orthodromic circus movement tachycardia due to a concealed accessory pathway. He presented with drug-resistant reentrant supraventricular tachycardia and, in a single session, underwent a successful radiofrequency catheter ablation of the fast atrial ventricular nodal pathway and a concealed posteroseptal accessory pathway. During a 10-month follow-up he was free of palpitations without any antiarrhythmic therapy and underwent elective aortic valve replacement.     

经主动脉无冠状窦内射频消融治疗房性心动过速

目的:报告经主动脉无冠状窦内射频消融6例局灶性房性心动过速(房速)的消融结果。方法:6例患者中男女各3例。阵发性房速病史(6±3)年。常规心电图、心内电生理,术中心房和心室刺激诱发房速,分别在右心房、左心房和主动脉无冠状窦内标测最早心房激动,并进行射频消融。结果:心房刺激能反复诱发和终止6例患者的房速。心房内的前间隔部位标测相对提前的心房激动,但多次消融未成功。经主动脉无冠状窦内消融成功。平均随访3~17个月,无1例房速复发。结论:经主动脉无冠状窦消融前间隔房速是安全,有效的。     

Catheter ablation of tachyarrhythmias from the aortic sinuses of Valsalva--when and how?

The aortic root is at the center of the heart. Each of the aortic sinuses of Valsalva, positioned at the base of the aortic root, is in contact with the atrial myocardium and/or ventricular myocardium at their bases, which enables mapping and ablating of some ventricular arrhythmias with an outflow tract origin and supraventricular tachycardias (ie, atrial tachycardia, accessory pathways) from the aortic sinuses of Valsalva. These arrhythmias have characteristic electrocardiographic findings associated with their origins, and almost all are difficult to ablate from an atrial or ventricular endocardial site. Site-specific and potential complications, such as a coronary artery occlusion or atrioventricular block, can occur with catheter ablation at the aortic sinuses of Valsalva. Therefore, accurate diagnosis and proper ablation at the aortic sinuses of Valsalva are required for a cure. This review describes the anatomic features of the aortic sinuses of Valsalva and focuses on the diagnosis and radiofrequency catheter ablation of arrhythmias that can be ablated from this site. (Circ J 2012; 76: 791-800).     

无冠窦起源房速的电生理特征与射频消融

目的进一步分析起源于主动脉无冠窦房性心律失常的心电生理特征及射频消融治疗。方法11例患者经心内电生理检查和射频消融证实的起源于主动脉无冠窦局灶性房速,对其临床特征,心电生理特点及射频消融进行分析。结果无冠窦房速大多为女性,表现为阵发性,为心房或心室程序刺激诱发和终止。所有患者房速心电图P波窄而低幅,Ⅱ,Ⅲ,aVF和v,导联P波负正双向,Ⅰ,aVL导联直立,V2～V6导联P波负向。心内最早激动位于希氏束远端,并领先于体表P波起始（15±3）ms。无冠窦内标测最早激动等于或早于希氏束远端,局部电位特征为大A小V（或大V）,无希氏束电位,11例患者无冠窦内放电均在8秒内终止心动过速,均无并发症,无抗心律失常药物随访12±5月所有患者均无心动过速复发。结论主动脉无冠窦房速有独特的临床特征,心电图特征及心房内激动顺序,长期随访这类房速射频消融有良好的治疗效果。     

Successful Targeted Ablation of the Pathway Potential in the Noncoronary Cusp of the Aortic Valve in an Infant with Incessant Orthodromic Atrioventricular Reentrant Tachycardia

A 4-month-old infant presented with incessant SVT and severe failure to thrive. At EP study, orthodromic-reciprocating tachycardia using an anteroseptal accessory pathway was identified. Detailed mapping on the right atrial septum failed to disclose a distinctly early site of atrial activation or a near-field pathway potential. Mapping in the noncoronary cusp of the aortic valve identified a discrete pathway potential that was successfully targeted for ablation. At 12-month follow-up after the procedure, there had been no recurrence of tachycardia.
Conclusion: Myocardial fibers above the aortic valve cusps may constitute the atrioventricular bypass connection and can be identified and targeted for successful ablation even in infants.     

Termination of pacemaker-mediated tachycardia by adenosine

A 30-year-old woman was referred for follow-up right- and left-heart catheterization 4 years after cardiac transplantation. She had an implanted epicardial pacemaker for bradycardia; this was programmed to the DDD mode. At the time of her catheterization, as a pigtail catheter was pulled back across the aortic valve, runs of premature ventricular complexes occurred and tachycardia with ventricular pacing spikes and ventricular capture was initiated at a rate of 126 beats/min. Adenosine 6 mg was given intravenously through a femoral venous sheath and within 20 s the tachycardia broke. The tachycardia was consistent with pacemaker-mediated tachycardia (PMT), a circus movement tachycardia occurring when ventricular pacing causes retrograde atrial depolarization followed by triggering of ventricular pacing. With reprogramming of the pacemaker to an AV delay of 160 ms and a postventricular atrial refractory period of 300 ms, no further episodes of PMT have occurred. This case illustrates that intravenous adenosine can effectively terminate PMT by causing ventriculoatrial block, thus interrupting the reentrant circuit by eliminating retrograde atrial activation.     

起源于主动脉窦内的房性心动过速、频发室性早搏的射频消融治疗

目的报道4例局灶性房性心动过速（房速）,3例频发室性早搏（室早）经主动脉途径在左冠窦和无冠窦内标测和射频消融的结果。方法对4例房速、3例频发室早进行常规心电图、心内电生理检查和射频消融治疗。结果4例阵发性房速患者的标测靶点位于主动脉窦内,在无冠窦成功消融;3例频发室早在左冠窦内标测及消融成功。术中无并发症,随访3～31个月,无1例复发。结论在主动脉无冠窦、左冠窦内射频消融是可行的且能达到安全、有效的治疗目的。尤其适用于在常规、经典部位消融失败的患者。     

Focal atrial tachycardia originating from the non-coronary aortic sinus: electrophysiological characteristics and catheter ablation.

OBJECTIVES: We sought to investigate electrophysiological characteristics and catheter ablation in patients with focal atrial tachycardia (AT) originating from the non-coronary aortic sinus (AS). BACKGROUND: In patients with failed ablation of focal AT near the His bundle (HB) region, an origin from the non-coronary AS should be considered because of the close anatomical relationship. METHODS: This study included 9 patients with focal AT, in 6 of whom attempted radiofrequency (RF) ablation had previously failed. Activation mapping was performed during tachycardia to identify an earliest activation in the atria and the AS. The aortic root angiography was performed to identify the origin in the AS before RF ablation. RESULTS: Focal AT was reproducibly induced by atrial pacing. Mapping in atria demonstrated that the earliest atrial activation was located at the HB region, whereas mapping in the non-coronary AS demonstrated that an earliest atrial activation preceded the atrial activation at the HB by 12.2 +/- 6.9 ms and was anatomically located superoposterior to the HB in all 9 patients. Also, His potentials were not found at the successful site in the non-coronary AS in all 9 patients. The focal AT was terminated in <8 s in all 9 patients. Junctional beats and PR prolongation did not occur during RF application in all 9 patients. No complications occurred in any of the nine patients. All 9 patients were free of arrhythmias without antiarrhythmic drugs during a follow-up of 9 +/- 3 months. CONCLUSIONS: In patients with focal AT near the HB region, mapping in the non-coronary AS can improve clinical outcome.     

Effect of cyclooxygenase inhibition on the adaptation of coronary blood flow to tachycardia

BACKGROUND: The role of different endothelium-derived vasoactive substances in the regulation of coronary circulation during tachycardia is not well defined. In order to elucidate the contribution of prostacyclin to the adaptation of coronary blood flow to tachycardia, the effect of meclofenamate, a cyclooxygenase inhibitor on the coronary blood flow response to rapid atrial pacing was analyzed in a porcine model. METHODS: A group of seventeen pigs were instrumented for coronary blood flow, aortic pressure and atrial pacing. Heart rate was increased by 20 beats every 5 minutes. Coronary blood flow and aortic pressure were measured, and coronary resistance calculated, basally and at each pacing interval, before and after saline serum (n = 6), meclofenamate 5 mg/kg, i.v. (n = 7) or meclofenamate 35 mg/kg, i.v. (n = 4). RESULTS: Neither saline nor meclofenamate modified the normal increase of coronary blood flow provoked by rapid atrial pacing (163 +/- 28% increase before versus 172 +/- 29% after saline; 159 +/- 21% increase before versus 161 +/- 22% after meclofenamate low doses and 201 +/- 39% before vs 172 +/- 36 after meclofenamate high doses). There were no differences in the response of coronary vascular resistance to tachycardia before and after meclofenamate (44% reduction vs 40% respectively). CONCLUSION: Cyclooxygenase blockade does not modify the response of coronary circulation to rapid atrial pacing, suggesting that prostacyclin does not play a limiting role in the regulation of coronary blood flow during tachycardia in this model.     

Catheter ablation of anteroseptal accessory pathway in the non-coronary aortic sinus.

We report a patient with atrioventricular reentrant tachycardia (AVRT) with bidirectional conduction over an anteroseptal accessory pathway (AP) who underwent successful ablation in the non-coronary aortic sinus (AS). In three previous attempts, the intracardiac recordings showed an anteroseptal AP with antegrade and retrograde conduction that failed to be ablated in spite of radiofrequency (RF) applications from the right and left anteroseptal regions. During the study, the earliest atrial activation during tachycardia was recorded in the non-coronary AS preceding the atrial activation at the His bundle (HB) region by 24 ms, and the anteroseptal AP was successfully blocked by one single ablation in the non-coronary AS. These data strongly suggest that careful mapping of an anteroseptal AP in the non-coronary AS may provide an alternative ablation approach in patients with previously failed ablation.     

Comparison of Atrial-His Intervals During Tachycardia and Atrial Pacing in Patients with Long RP Tachycardia

Long RP Tachycardia. Introduction : The purpose of this study is to describe a simple and reliable diagnostic maneuver that allows for the rapid differentiation of atypical AV nodal reentrant tachycardia (AVNRT) from other causes of long KP tachycardia. Long RP tachycardias may he caused by atypical AVNRT, orthodromic reciprocating tachycardia (ORT) involving a slowly conducting retrograde accessory pathway, or atrial tachycardia. The differentiation of atypical AVNRT from ORT or atrial tachycardia may be difficult, especially when the differential diagnosis includes a posteroseptal accessory pathway or an atrial tachycardia arising in the posteroseptal right atrium.
Methods and Results : Twelve patients with atypical AVNRT, 21 with ORT, and 12 with an atrial tachycardia diagnosed using conventional criteria were enrolled In this study. The atrial-His (AH) interval was measured at the His-bundle position during the tachycardia and during atrial pacing from the high right atrium at the tachycardia cycle length in the setting of sinus rhythm. In patients with atypical AVNRT, the mean AH interval was 69 msec ± 50 msec (± SD) longer during high right atrial pacing than during the tachycardia (P < 0.001). In 10 of 12 patients with atypical AVNRT, the AH interval during atrial pacing was more than 40 msec longer than the AH interval measured during the tachycardia. In contrast, in patients with ORT or atrial tachycardia, the differences in AH interval between atrial pacing and tachycardia were never more than 20 and 10 msec, respectively.
Conclusion : The difference in the AH interval between atrial pacing and the tachycardia allows a simple and rapid means of differentiating atypical AVNRT from other types of long RP tachycardias.     

Atrial tachycardia originating at the tricuspid annulus

We report a patient with re-entrant atrial tachycardia that originated at the inferolateral tricuspid annulus. Single atrial extra-stimulation reproducibly induced the atrial tachycardia with an inverse relationship between the coupling interval of extra-stimulation and the return cycle of the first tachycardia beat. A real-time three-dimensional electroanatomical mapping showed focal atrial activation spreading semi-radially from the tricuspid annulus. The tachycardia was successfully eliminated by radiofrequency ablation at the earliest atrial activation site, preceding by 27 ms the arbitrary determined onset of surface P wave. An accelerated atrial rhythm with similar P-wave morphology to that of the tachycardia was observed at the successful ablation site during radiofrequency application. The mechanism of this tachycardia seems to be due to re-entry originating in or around the possible accessory atrioventricular node without ventricular connection.     

Electrophysiological and clinical characterization of left atrial macroreentrant tachycardia]

BACKGROUND AND OBJECTIVE: We are reporting the characteristics of 9 patients with left atrial macroreentrant tachycardia, an arrhythmia not well studied in man. PATIENTS AND METHOD: Mean age was 60 years and 7 were men. Tachycardia was spontaneous in 6 and induced in 3. Two had no heart disease, 2 sick sinus syndrome, 3 aortic prosthesis, 2 hypertension, 1 cardiomyopathy and 1 chronic bronchitis. Simultaneous recordings from right atrial, coronary sinus and right pulmonary artery were obtained at baseline and with atrial pacing. Macroreentrant tachycardia was diagnosed when entrainment with fusion was documented. RESULTS: Cycle length was 230-440 ms (287 67). The ECG showed atypical flutter in 3 patients and P waves with flat baseline in 6. Coronary sinus activation was distal to proximal in 7. Right atrial activation was circular in 3 with previous typical flutter ablation. Entrainment from the right atrium produced long return cycles in the right atrial recordings, but equal to basal tachycardic cycle in coronary sinus recordings. Entrainment from the coronary sinus produced local return cycles equal to basal cycle in 8 and prolonged in 1. After stimulation, 4 recovered sinus rhythm, 4 went to atrial fibrillation and 1 had no change. After a follow-up of 9-19 months 5 remain in sinus rhythm treated with antiarrhythmic drugs and/or atrial pacing. CONCLUSIONS: Left atrial macroreentrant tachycardia is associated with organic heart disease. The ECG most frequent pattern tends to show P waves with flat baseline at a relatively slow rate. Most circuits turn clockwise in anterior view. Atrial stimulation is not very effective for cardioversion to sinus rhythm. The prognosis of long term rhythm is uncertain.     

Evidence of mechanoelectric feedback in the atria of patients with atrioventricular nodal reentrant tachycardia

Objective Patients with atrioventricular nodal reentrant tachycardia (AVNRT) could serve as a clinical model to study the effects of mechanical stretch in the electrical properties of atrial myocardium.Materials and methods We studied 14 patients with AVNRT. Peak, mean and minimal atrial pressures, atrial refractoriness (ERP) in the right atrial appendage and high right atrial lateral wall and monophasic action potential duration at 90% of repolarisation (MAPd90) in the right atrial appendage were assessed during atrial pacing at 500 and 400 ms and after 2 min of pacing at the tachycardia cycle length. Measurements were repeated from the same positions after ventricular pacing at the same cycle lengths and after 2 min of tachycardia. Susceptibility to atrial fibrillation (AF) was assessed by noting whether AF was induced during ERP evaluation.Results Atrial pressure showed a statistically significant increase during ventricular pacing compared to baseline. This increase remained substantially unchanged when the tachycardia was induced. A significant reduction in atrial ERP and MAPd90 was also observed during ventricular pacing at all cycle lengths compared to atrial pacing. Two minutes of spontaneous tachycardia were enough to change the atrial ERP and MAPd90 to values significantly lower than those during atrial pacing at the cycle length of tachycardia. During the ERP evaluation AF was induced more often during the tachycardia (28%) than during ventricular (14%) and atrial pacing (0%).Conclusion In AVNRT patients, ventricular pacing and reentrant tachycardia significantly increase right atrial pressures and subsequently shorten ERP and MAPd90, leading to an enhanced propensity for AF.     

Effect of atrioventricular synchrony on stroke volume during ventricular tachycardia in man.

The hemodynamic consequences of atrioventricular (AV) synchrony during ventricular tachycardia were evaluated during cardiac electrophysiologic testing. The relationship between stroke volume and the AV interval was investigated on a beat-by-beat basis in six patients during induced monomorphic ventricular tachycardia. Stroke volume was calculated either (1) in the right ventricle using impedance catheter method (four patients) or (2) in the left ventricle using Doppler measurement of aortic blood velocity (two patients). The impedance catheter method underestimated stroke volume by a factor of 4.2 +/- 2.4 compared with the thermodilution cardiac output method. However, there was a highly linear relationship between both methods for computing stroke volume (r greater than 0.9). Five patients had complete AV dissociation during ventricular tachycardia, and different AV intervals spanned the entire tachycardia cycle lengths. Largest stroke volumes were associated with optimal AV intervals within 120 and 230 msec, resulting in a 97 +/- 59% increase in stroke volume over ventricular tachycardia cycles not associated with atrial activity. Customized atrial pacing during ventricular tachycardia may provide a valuable means for artificially establishing the hemodynamically optimal AV interval and eliminating the ventricular tachycardia cycles not preceded by atrial activity.     

Atrial tachycardia without P waves masquerading as an A-V junctional tachycardia.

Two patients who presented by scalar ECG with an A-V junctional tachycardia were demonstrated during an electrophysiologic evaluation to have an atrial tachycardia without P waves in the surface ECG. Case 1 had an atrial tachycardia that conducted through the A-V node with a Wenckebach block. Atrial activity was recorded only from the proximal portion of the coronary sinus and from right atrial areas near the tricuspid valve. Case 2 had an atrial tachycardia that abruptly began and terminated following carotid sinus massage. Atrial activity was recorded only in the coronary sinusos, and pacing at that site resulted in atrial capture, with Wenckebach conduction to the ventricles. These observations demonstrate that an atrial tachycardia without P waves can simulate A-V junctional tachycardia with or without Weckebach block. Such findings may have a bearing on some important electrophysiologic concepts such as the origin of A-V junctional rhythms and the need for atrial participation in A-V nodal re-entry.     

Permanent junctional reciprocating tachycardia (Coumel type): an unusual location of a retrograde accessory pathway

Permanent junctional reentrant tachycardia (PJRT) is an uncommon form of tachycardia that is usually due to an atrioventricular reentry via a right posteroseptal accessory pathway with decremental properties. We describe a case of PJRT that showed evidence of two accessory pathways located both left and right. A 63-year-old woman was referred to our institution for radiofrequency (RF) ablation of a permanent form of regular narrow QRS tachycardia (T) (cycle length 520 ms) with long RP interval (380 ms); P wave was negative in inferior leads, negative in D1 and flat in aVL. During sinus rhythm, AH and HV intervals were 110 ms and 50 ms respectively. The atrioventricular anterograde conduction curve was continuous. A decremental retrograde conduction via a left posterior pathway until ventricular effective refractory period (210 ms) was evident. Tachycardia inducible with both atrial and ventricular programmed stimulation was almost incessant. During tachycardia, a premature ventricular depolarization delivered when His bundle was refractory was able to advance the next atriogram, and tachycardia could be interrupted by a ventricular depolarization without atrial capture. During right atrial mapping, an earliest atrial activation was found in the mid-septal position just above the coronary sinus ostium and RF application caused a transient interruption of T (3 minutes). Tachycardia resumed with basal characteristics, but no evidence of earlier right atrial activation was found during atrial mapping. Successful RF ablation was performed via retrograde aortic catheterization in the left posterior region. This case showed evidence of a left posterior pathway causing PJRT. However, the transient successful ablation in the right mid-septal region and the lack of evidence of right early atrial activation after RF application could account for the presence of an additional right accessory pathway or a strand of the same broad left pathway.     

Intravenous flecainide acetate for supraventricular tachycardias

Flecainide acetate, 2 mg/kg body weight, given intravenously at 10 mg/min was administered to 128 (74 male and 54 female) patients whose ages ranged from 11 to 86 years (mean 44). All patients had supraventricular tachycardias (SVT) that developed spontaneously or were induced during electrophysiologic study. There were 26 patients with atrial flutter, 34 with atrial fibrillation, 7 with ectopic atrial tachycardia, 41 with atrioventricular (AV) reentrant tachycardia and 40 with AV nodal reentrant tachycardia. Twenty patients had more than 1 variety of SVT. Flecainide was administered during SVT to 9 patients with atrial flutter, 11 with atrial fibrillation, 7 with atrial tachycardia, 38 with AV reentrant tachycardia and 34 with AV nodal reentrant tachycardia. In the remaining 31 patients with inducible SVT at electrophysiologic study, flecainide was administered during sinus rhythm. Reinitiation of SVT was attempted in these patients after completion of flecainide administration. Flecainide successfully terminated atrial flutter in 2 patients (22%), atrial fibrillation in 9 (82%), atrial tachycardia in 5 (71%), AV reentrant tachycardia in 32 (84%) and AV nodal reentrant tachycardia in 30 (88%). Reinitiation of SVT was possible in 10 of 26 patients with atrial flutter (38%), 5 of 34 with atrial fibrillation (15%), 3 of 7 with atrial tachycardia (43%), 14 of 41 with AV reentrant tachycardia (34%) and 11 of 40 with AV nodal reentrant tachycardia (27%). In patients with AV reentrant tachycardia and AV nodal reentrant tachycardia, reinitiation occurred when retrograde anomalous pathway refractoriness was not significantly prolonged by intravenous flecainide.(ABSTRACT TRUNCATED AT 250 WORDS)