Accessory pathway ablation: When the going gets tough, the tough go epicardial.

0038: Impact of accessory pathway ablation on the risk of atrial fibrillation in patients with overt conduction and patients with concealed conduction over accessory pathway

Pulmonary vein antrum isolation (PVAI) of pre-excited atrial fibrillation (AF) is controversial. This study aimed to observe the therapeutic effects of PVAI on pre-excited AF. Twenty-nine patients with pre-excited AF were prospectively divided into a PVAI group (group I, 19 cases) and a control group (group II, 10 cases). To each case in group I, PVAI was performed, and then electroanatomical mapping of accessory pathways (AP) and ablation were constructed on a three-dimensional (3D) map of the valve annulus. Only AP ablation was performed in each case of group II. Of the 29 cases, three were found to have dual APs, two had intermittent APs, and the remaining 24 had single APs. All APs were successfully ablated after the procedure. There were no significant statistical differences in the AP procedure duration ((77.4 ± 21.3) minutes vs. (85.3 ± 13.1) minutes), the AP ablation time ((204 ± 34) seconds vs. (223 ± 62) seconds) and the AP X-ray exposure time ((18.6 ± 4.4) minutes vs. (19.1 ± 4.5) minutes) respectively between groups I and II. As compared with the control group (5 of 10 cases, 50%), the PVAI group had a significantly lower AF recurrence rate (2 of 19 cases, 11%; P < 0.05) during follow-up of (20.5 ± 10.0) months. All seven patients who recurred were successfully abolished by a second ablation. In patients with pre-excited AF, PVAI is an effective therapeutic approach with a low AF recurrence rate. 3D electroanatomical maps of AP contributed to the high success rate of ablation without significantly prolonging of operational duration and X-ray exposure time.

Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed. We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access. Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial-epicardial approach.

Catheter ablation of coronary sinus accessory pathways in the young

The past 5 years have seen the introduction into the preclinical arena of myriad devices for the potential treatment of functional and ischemic mitral regurgitation by a percutaneous approach.1 A number of the device concepts have taken advantage of the relatively easy access to the posterior annulus of the mitral valve provided by the coronary sinus. Although attractive on initial consideration as a delivery route for devices that remodel the posterior mitral annulus, a number of potential shortcomings to this approach may ultimately limit its clinical success. Article p 377 Annular remodeling of the mitral valve for functional mitral regurgitation (FMR) has been demonstrated to have short-term and some intermediate-term efficacy in the clinical surgical setting.2 The pathophysiology of FMR in patients with dilated cardiomyopathy is central regurgitation caused by failure of mitral leaflet coaptation. The causes of this malcoaptation are multifactorial and include annular dilatation and ventricular dilation, which cause apical distraction of the papillary muscles, producing tethering of the mitral leaflets. Although the whole annulus has been demonstrated to dilate in FMR, there is a disproportionate increase in the anterior-posterior or septal-lateral diameter.3,4 The basic premise behind the surgical approach is that through the use of an undersized ring to overcorrect the dilation of the mitral annulus, both the annular dilatation and the tethering of the leaflets from apical papillary muscle displacement can be treated. The tenets for optimal surgical …

Radiofrequency (RF) catheter ablation is the treatment of choice in patients with accessory pathways (APs) and Wolff-Parkinson-White syndrome. Endocardial catheter ablation has limitations, including the inability to map and ablate intramural or subepicardial APs. Some of these difficulties can be overcome using an epicardial approach performed through the epicardial venous system or by percutaneous catheterisation of the pericardial space. When a suspected left inferior or infero-paraseptal AP is refractory to ablation or no early activation is found at the endocardium, a transvenous approach via the coronary sinus is warranted because such epicardial pathways can be in close proximity to the coronary venous system. Associated congenital abnormalities, such as right atrial appendage, right ventricle diverticulum, coronary sinus diverticulum and absence of coronary sinus ostium, may also hamper a successful outcome. Percutaneous epicardial subxiphoid approach should be considered when endocardial or transvenous mapping and ablation fails. Epicardial mapping may be successful. It can guide and enhance the effectiveness of endocardial ablation. The finding of no epicardial early activation leads to a more persistent new endocardial attempt. When both endocardial and epicardial ablation are unsuccessful, open-chest surgery is the only option to eliminate the AP.

Radiofrequency (RF) catheter ablation is the treatment of choice in patients with accessory pathways (APs) and Wolff–Parkinson–White syndrome. Endocardial catheter ablation has limitations, including the inability to map and ablate intramural or subepicardial APs. Some of these difficulties can be overcome using an epicardial approach performed through the epicardial venous system or by percutaneous catheterisation of the pericardial space. When a suspected left inferior or infero-paraseptal AP is refractory to ablation or no early activation is found at the endocardium, a transvenous approach via the coronary sinus is warranted because such epicardial pathways can be in close proximity to the coronary venous system. Associated congenital abnormalities, such as right atrial appendage, right ventricle diverticulum, coronary sinus diverticulum and absence of coronary sinus ostium, may also hamper a successful outcome. Percutaneous epicardial subxiphoid approach should be considered when endocardial or transvenous mapping and ablation fails. Epicardial mapping may be successful. It can guide and enhance the effectiveness of endocardial ablation. The finding of no epicardial early activation leads to a more persistent new endocardial attempt. When both endocardial and epicardial ablation are unsuccessful, open-chest surgery is the only option to eliminate the AP.

Atrial tachycardia arising from the distal left atrial appendage requiring high-power endocardial and epicardial ablation

By definition, accessory atrioventricular pathways are aberrant muscle bundles that connect the atrium to a ventricle outside of the regular atrioventricular conduction system. Clinically, they may manifest as substrates for ventricular preexcitation. The first accessory pathway in a patient who suffered from Wolff-Parkinson-White syndrome was described in 1943 by Wood, Wolferth, and Geckler.1 Shortly after, Ohnell created a reconstruction of an accessory pathway that very elegantly showed the close proximity of the pathway to the fibrous attachment of the mitral valve and its relationship with the sulcus coronarius (Figure, A).2 Subsequent histological studies have demonstrated unequivocally that these pathways are the anatomic substrates for the classical Wolff-Parkinson-White variety of preexcitation. Figure. A, Ohnell’s depiction of an accessory bundle in the left atrioventricular groove.2 Reprinted with permission from Blackwell Publishing. B, Histological section stained with Masson’s trichrome (fibrous tissue in green and myocardium in red) to show an accessory left-sided pathway (arrow) skirting the mitral annulus. C, Histological section showing a broad right-sided accessory pathway (arrow) that is formed by a myocardial pouch extending from the right atrial appendage to the ventricle and ultimately traced to a small right ventricular vein. This pathway is some distance from the fibrous annulus of the tricuspid valve. *Valvar annulus. Article p 1508 Accessory atrioventricular pathways are found most often in the parietal atrioventricular junctional areas, including the paraseptal areas. They breach the insulation provided by the fibrofatty tissues of the atrioventricular groove (sulcus tissue) and the hingelines (fibrous annulus) of the valves. They are rarely found in the area of fibrous continuity between the aortic and mitral valves because in this area, there is usually a wide gap between the atrial myocardium and ventricular myocardium to accommodate the aortic outflow tract. On the left parietal side, the accessory pathways tend …

Introduction: Ebstein’s anomaly is a rare abnormality of the heart associated with atrialization right ventricle and apical (downward) displacement of the tricuspid valve functional annulus. Twenty percents of patients with Ebstein’s anomaly accompanied with accessory pathway. The dilatation of atrium and aging process may develop atrial fibrillation (AF).Case Description: A 35 years old patient with recurrency palpitation, accompanied with dizziness and epigastric discomfort. He had history of taking propafenone 3 x 150 mg for long time while the palpitation recurrent. He was hospitalization due to propafenone could not suppress the palpitation. During monitor in hospital revealed haemodynamic stable with heart rate 160-180 beats/minute irregularly irregular. The electrocardiography showed atrial fibrillation with pre-excitation WPW syndrome. We performed electrical cardioversion 100 joule. Then the atrial fibrillation was convert to sinus rhythm with WPW pattern. The propafenone 3 x 150mg was continued. The patient was performed catheter radiofrequency ablation of the accessory pathway. Electrophysiology showed AV fusion at right anteroseptal pathway and preexcited atrial fibrillation with shortest RR interval 220 ms that converted by cardioversion. The ablation was successfully performed. Discussion: The accessory pathway is a complication of ebstein anomaly. Digoxin, beta-blockers, diltiazem, verapamil, and amiodarone are potentially harmful in pre-excited atrial fibrillation. Propafenone reduces fast inward potential by sodium channels, reduces spontaneous automaticity and prolongs the effective refractory periode so could be used in this case. Catheter ablation of accessory pathway in Ebstein anomaly with WPW syndrome was class I recommendation. In our case, the accessory pathway was successfully ablated.

1008-14 Radiofrequency Catheter Ablation of Left-sided Accessory Pathways: Selection of Coronary Sinus as the Primary Approach

Localization and radiofrequency catheter ablation of left-sided accessory pathways during atrial fibrillation Feasibility and electrogram criteria for identification of appropriate target sites

Percutaneous epicardial mapping during ablation of difficult accessory pathways as an alternative to cardiac surgery

A 20-year-old man with no past medical history experienced a syncopal episode. He was found to be pulseless, and cardiopulmonary resuscitation was initiated. When emergency medical service arrived, rhythm strip showed an irregular wide-complex tachycardia consistent with preexcited atrial fibrillation with cycle length as short as 180 ms (333 beats per minute) (Figure 1A). He was defibrillated successfully into sinus rhythm. A 12-lead ECG showed sinus rhythm with PR interval of 110 ms, delta waves and pseudo-infarct pattern in the inferior leads consistent with a posteroseptal accessory pathway (Figure 1B). He was referred to us for an electrophysiology study. Figure 1. A, Rhythm strip of patient during the cardiac arrest, showing irregular wide-complex tachycardia very suggestive of preexcited atrial fibrillation. B, 12-lead ECG after resuscitation. The short PR interval, delta wave and pseudo-infarct pattern in the inferior leads are consistent with the presence of a manifest accessory pathway (Wolff-Parkinson-White Syndrome). During the procedure, extensive mapping in the right atrium, the coronary sinus (CS) and its branches, and the left atrium (via transseptal approach) was performed. A CS angiogram showed the presence of a diverticulum. The area of earliest ventricular …

Due to the limited myocardial lesions produced by radiofrequency current, the ablation of accessory pathways (AP) requires precise localization of such connections. The purpose of this study was to ascertain which characteristic(s) of the local bipolar electrogram, recorded from the ablation and adjacent electrode immediately prior to the application of radiofrequency current, correlated with precision in localization adequate to permit AP ablation. Signal analysis was performed for 326 sets of electrograms preceding the attempted ablation of 107 APs in 100 consecutive patients. For 80 antegrade APs, the following variables were evaluated: (1) the presence or absence of an AP potential; (2) the local atrial-AP interval; (3) the local atrioventricular (AV) interval; and (4) the relationship between the onset of local ventricular depolarization and onset of delta wave of the surface electrocardiogram. For the 27 concealed APs, the following characteristics were evaluated: (1) the presence or absence of an AP potential; and (2) the local VA interval during reciprocating tachycardia or ventricular pacing. Antegrade APs: By statistical analysis, the best correlate of successful ablation of an antegrade AP was a local AV interval less than or equal to 40 msec (positive predictive value = 94%; 95% confidence intervals [CI] = 81%-100%). Local AV intervals less than or equal to 50 msec preceded 88% of successful AP ablations, compared to only 8% of failed radiofrequency current applications. The positive predictive value of the other variables were: presence of an AP potential: 35% (95% CI = 27%-40%); local atrial-AP intervals less than or equal to 40 msec: 54% (95% CI = 43%-66%); and local ventricular depolarization preceding onset of the delta wave 43% (95% CI = 34%-52%). For concealed APs, the positive predictive value of a VA interval less than 60 msec was 71% (95% CI = 48%-88%); the positive predictive value for the presence of an AP potential was 58% (95% CI = 32%-81%). No single electrogram characteristic had a positive predictive value and a sensitivity greater than 90% for AP localization adequate for radiofrequency current ablation. For antegrade APs, the best correlate of adequate localization was a local AV interval less than or equal to 40 msec; as a corollary, radiofrequency current applications at sites where the local AV was greater than 60 msec, were unlikely to be effective. Objective criteria for the localization of concealed APs were less certain. Electrogram analysis, as a guide to AP localization and ablation, requires careful analysis of multiple variables, with analysis of the local AV interval a salient objective factor.