Y Guitang

ASSA14-02-04 Electrophysiologic Characteristics and Radiofrequency Catheter Ablation of Atrial Arrhythmia originating from Superior Vena Cava

Objectives To analyse the characteristics of electrocardiogram (ECG) and electrophysiologic and radiofrequency catheter ablation (RFCA), to investigate the diagnosis and strategy of ablation of Atrial Arrhythmia originating from Superior Vena Cava. Methods Choose 14 patients from 2002–2013, all patients acknowledged atrial arrhythmia (atrial fibrillation (AF), atrial tachycardia (AT)) originating from superior vena cava by electrophysiologic examination. 6 of them were male, and the mean age of the 14 patients was 56 ± 7 years, mean case history was 8 ± 7 years. Analyse the ECG P’ waves of atrial premature or atrial tachycardia and electrophysiologic characteristics. When atrial fibrillation, atrial tachycardia happens, identify the origin location and the earliest activation, under the guidance of traditional mapping or three-dimensional (3D) mapping system, combined SVC angiography, if certify SVC is the origin of triggering arrhythmia, ablate the SVC focally, segmentally or circularly. Results Though the 14 cases of atrial arrhythmia originated from SVC, We found that the ECG P’ waves characteristics: 13 patients the P’ waves in lead I were positive, 1 was isoeleetric; 14 patients the P’ waves in lead II were positive, and the amplitude was higher than sinusus P wave; 12 patients the waves in lead III were positive, 2 were positive negative; 13 patients the P’ waves in lead AVF were positive, 1 was isoeleetric; 14 patients the P waves in lead AVR were all negative; the patients of P’ waves in lead V1 positive, negative, positive negative, isoeleetric was 5, 3, 4, 2 respectively. Compared with the sinusus P wave, the P’ waves was significantly higher in lead II, III, AVF. The electrophysiologic characteristics: In SVC and right superior pulmonary veins (RSPV), could record SVC potential, which ahead of coronary sinus ostium (CSO) 50 ± 11 ms sinus rhythm, 93 ± 20 ms atrial premature, p < 0.01; SVC electric activity may trigger atrial fibrillation, atrial tachycardia, compared with the any other positions of atrium, SVC electric activity has the feature of earlier excitation and faster frequency; pacing SVC may trigger atrial fibrillation, atrial tachycardia; during the ablation of SVC, SVC remain the quick and confused electric activity when AF transferred sinus rhythm, however the atrium was stable electric activity, during continuing ablation, the SVC potential disappears, sometimes SVC automatic happens. 5 patients of AT ablated successly instantly, 9 patients of AF and atrial premature, mapping and ablation under the 3D mapping system, 1 patient happened sinus arrest, 1 happened cardiac tamponade. No surgery relevant complication and recurrence during follow up. Conclusions Atrial arrhythmia originating from superior vena cava has typical ECG characteristics: P’ waves in lead II, III, AVF was significantly higher than sinusus P wave. The time limit of SVC potential ahead of CSO both sinus rhythm and atrial premature has direction meaning to some extent, which could improve the success rate and decrease recurrence rate. The focal ablation and segmental ablation of SVC could achieve SVC-RA completely electrical isolation. SVC is adjacent to atrionector and right nervus phrenicus anatomically, 3D mapping system is helpful to identify anatomy and target location.

ASSA14-02-09 The strategy of radiofrequency catheter ablation in special left accessory pathway

Objective To explore the strategy of radiofrequency catheter ablation in special left accessory pathway. Methods From January 2013 to December 2013, total 288 patients with left accessory pathway were ablated in our hospital. Among them, special left accessory pathways were found in 13 patients. Gap phenomenon was found in 6 patients, slow accessory pathway in 2 patients, combination with persistent left superior vena cava in 3 patients, peripheral vascular serious circuity in 1 patient, combination with atrial fibrillation and atrial flutter in 1 patient. All the patients were ablated through aortic retrograde approach, transseptal approach and via coronary sinus approach. Results Thirteen patients were all ablated successful. Eight patients were ablated through aortic retrograde approach, and four patients with left side accessory pathway were accomplished through transseptal approach, and one patient were ablated via coronary sinus. The success rate was 100%, and complication was not occurred. Gap phenomenon was found in 6 patients with no adverse transmission above 400 ms stimulation and with adverse transmission under 350 ms stimulation. Heart rate and blood pressure were decreased in one patient with persistent left superior cave during ablation. ST-T changing in ECG was confirmed no coronary artery disease, and considered left boundle branch block. Two patients with slow accessory pathway were ablated in left free wall where VA was not fused. One patient with poliovirus and peripheral vascular serious circuity was ablated through transseptal approach after failure via aortic retrograde approach. One patient with atrial fibrillation and atrial flutter was ablated in coronary vein successful. Conclusions During ablation in left accessory pathway, we may get into trouble in some cases. After identifying carefully and ablation through different methods, high success rate was still obtained.

ASSA14-02-06 Radiofrequency Catheter Ablation of Ventricular Tachycardia After Repair of Congenital Heart Disease

Objective This study was designed to discuss the mechanism, critical isthmus, the characteristics of surface electrocardiogram (ECG) and the strategy of ablation of ventricular tachycardia (VT) after repair of congenital heart disease in order to increase the success rate and safety of radiofrequency catheter ablation (RFCA). Methods Eleven consecutive patients (9 men and 2 women, aged 6∼41 years) with recurrent and symptomatic VT after repair of congenital heart disease were investigated. Nine patients had undergone surgical repair of tetralogy of Fallot (TOF), 1 patient had an operation for severe congenital pulmonary stenosis and patch closure of ventricular septal defect (VSD) and suture of atrial septal defect (ASD), and the remaining patient had repair of trilogy of Fallot combined with right ventricular cardiomyopathy. The ECG showed sustained VTs in 10 patients and unsustained VTs in 1 patient, and 4 patients had the histories of syncope. Substrate mapping of the right ventricle during sinus rhythm was performed in all 11 patients. Unexcitable tissue identified from bipolar voltage (<0.5 mV) and uncaptured ventricular regions was defined as the scar or surgical patch, and the possible conduction channel between scar/patch and valve annulus (tricuspid annulus and pulmonary annulus) was defined as anatomic isthmus. Five possible isthmuses were as follows: (1) the tricuspid annulus and scar/patch in the anterior right ventricular outflow (isthmus 1), (2) the pulmonary annulus and right ventricular free wall scar/patch (isthmus 2), (3) the pulmonary annulus and septal scar/patch (isthmus 3), (4) the septal scar/patch and tricuspid annulus (isthmus 4), and (5) the scar/patch in the anterior right ventricular outflow and septal scar/patch (isthmus 5). The methods for mapping and ablating VT were as follows. If the induced VTs were hemodynamically stable, the VT mapping techniques included activation mapping and voltage mapping, combined with entrainment mapping and diastolic potentials mapping to ablate critical isthmuses. For VTs that were unstable or could not be induced, high density substrate mapping was performed at potentially critical isthmuses of the right ventricle, radiofrequency energy was delivered as linear lesions based on the location of the best pace map and the sites with special potentials to anatomic boundaries. Results In 9 patients after surgical repair of TOF, 19 different monomorphic VTs (cycle length, 170∼350 ms) could be induced; 15 were documented as clinical VTs, 2 VTs were hemodynamically unstable. In 1 patient of having an operation for severe congenital pulmonary stenosis and patch closure of VSD and suture of ASD, 1 nonsustained VT could be induced, the clinical 2 VTs could not be induced. Five morphologies of nonsustained VT could be induced in the remaining patient who had repair of trilogy of Fallot combined with right ventricular cardiomyopathy. In 10 patients who had surgical repair of TOF or severe congenital pulmonary stenosis and patch closure of VSD and suture of ASD, mapping and ablation was performed during VTs in 4 patients. In the other 6 patients, mapping and ablation was performed during sinus rhythm. The sites of surgical correction of the right ventricle were associated with the origins of VTs in these 10 patients. Combined with QRS morphology during VT and the results of mapping and ablation, anatomic isthmus 2 were ablated in 8 patients, isthmus 3 ablated in 8 patients, isthmus 5 ablated in 4 patients, and isthmus 4 ablated in 1 patient. Isthmus 2 and 3 as the reentry circuit critical isthmuses were more common. In the patient of having repair of trilogy of Fallot combined with right ventricular cardiomyopathy, 5 morphologies of nonsustained VTs (cycle length, 250∼310 ms, left bundle-branch block) could be induced, 2 were clinical VTs. Combined with the information of surgical operation method and the result of electroanatomic mapping, these VTs were considered being relevant with right ventricular cardiomyopathy, but not the surgical operation of congenital heart disease. Radiofrequency energy was delivered around the scar of the right ventricle apex and at the sites with late potential within the scar. All the 25 VTs induced in the 11 patients were caused by scar related reentry. Catheter ablation achieved acute success in 10 patients, including elimination of all VTs in 9 patients, and elimination of the clinical VTs in 1 patient. Ablation of VTs failed in the remaining patient with TOF because of lacking of inferior vena cava. During 3 months to 9 years of follow up, VTs recurred in 3 patients. Two of them had a successful ablation of VTs in the second procedure, and 1 patient had success in the third procedure. Conclusions Reentry circuit isthmuses in VTs late after repair of congenital heart disease are located within anatomically defined isthmuses bordered by unexcitable tissue of scar, patch or valve annulus. The isthmuses between the pulmonary annulus and right ventricular free wall scar/patch (isthmus 2), and between the pulmonary annulus and septal scar/patch (isthmus 3) were more common. In addition, the boundary between the scar/patch in the anterior right ventricular outflow and septal scar/patch (isthmus 5) could also be the critical isthmus of VT. RFCA of these 3 isthmuses could increase the success rate of VT after repair of congenital heart disease. The information of surgical operation prior to ablation and ventricular angiogram during the procedure were very important to predict critical isthmuses and direct electroanatomic mapping. Based on the electroanatomic mapping, RFCA of critical isthmuses of VTs in patients after repair of congenital heart disease might have a high success rate and a low recurrence, especially for unmappable VTs.

ASSA14-02-07 Electrophysiologic Characteristics and Radiofrequency Catheter Ablation of Right-Sided Free Wall Accessory Pathway Refractory to Conventional Technique

Objective In recent years, radiofrequency catheter ablation of right-sided atrioventricular accessory pathway (AP) has improved significantly due to improved ablation catheter, using the long sheath support, application of 3D mapping system and saline-irrigated ablation catheter. However, catheter ablation of the right-sided free wall AP is very difficult in a few cases by using the conventional technique. Some studies reported that the reasons for the difficulty of ablation were the abnormal AP location between the right atrial appendage and right ventricle, or the insertion point of AP away from the tricuspid annulus or the existence of epicardial AP, but the final conclusion has not been reached. The purpose of this study was to investigate the electroanatomical structure, the cardiac electrophysiological characteristics and the ablation strategy of right-sided free wall AP refractory to conventional ablation technique. Methods Study population consisted of 535 patients (332 males, aged 1 to 82 years) underwent cardiac electrophysiological study and radiofrequency catheter ablation of right-sided AP. All patients had the history of atrioventricular reentrant tachycardia (AVRT). The surface ECG present pre-excitation syndrome in 325 patients, accounting for 60.7% of right-sided APs. 9 patients had structural heart disease. 24 patients had 1–2 times of a failed catheter ablation or recurrence. Ablation of right-sided AP was performed by mapping the earliest pre-excitation ventricular activation site at the tricuspid annulus during sinus rhythm or atrial pacing, or by mapping the earliest atrial activation site during ventricular pacing or AVRT. If repeated ablation attempts failed to eliminate the AP conduction by the above conventional technique, further ablation was performed by mapping and ablating the earliest atrial activation at the tricuspid annulus or its atrial sides until isolation of the AP conduction. Results Twenty-two patients had refractory right-sided free wall APs, accounting for 4.1% of all right-sided AP patients (22/535 patients), among them 6 cases had a history 1–2 times failed ablation procedures. Of the 22 patients, 3 patients (3.0%, 3/101 patients) had right-sided antero-lateral free wall APs, 19 patients (7.5%, 19/253 patients) had right-sided postero-lateral free wall APs. Nine patients had pre-excitation syndrome, and 13 patients had a concealed AP. Conventional ablation failed to eliminate the AP conduction in all the 22 patients, multiple times of ablation were tried point by point to the sites with earliest atrial activation during AP conduction at the tricuspid annulus or its atrial sides. During ablation, the VA intervals (measured from the onset of QRS wave in surface ECG to the atrial activation of coronary sinus catheter and His bundle catheter) gradually prolonged for 20 to 80 ms in all patients. In the 3 patients with right-sided antero-lateral free wall AP, 1 patient had a successful ablation, 2 patient failed and 1 of them was cured by cardiac surgery. In the 19 patients with right-sided postero-lateral free wall AP, 17 patients had successful ablation, and 2 patients failed. During a period of 1–6 years of follow-up, the 19 patients with successful ablation were free of recurrence. Conclusions Although conventional ablsation technique could successfully eliminate most of right-sided APs, but a few of right-sided free wall APs (accounting for 4.1% of all the right-sided APs and 6.2% of all the right-sided free wall APs) were refractory or resistant to the conventional ablation technique. By using linear ablation along the tricuspid annulus and its atrial sides to isolate the AP conduction could abolish the APs in most patients with refractory right-sided free wall APs. However, because of a long procedure time, a high-level catheter ablation technique needed, and patient’s safety consideration, the indication of this technique should be strictly used and assessed.

ASSA14-02-11 Catheter ablation of anteroseptal accessory pathway: Implication for the strategies of mapping and ablation

Objective Catheter ablation of anteroseptal atrioventricular (AV) accessory pathway (AP) is still challenging because of their proximity to the normal AV conduction system that may be damaged with ablation. Traditionally, catheter ablation of anteroseptal APs via the inferior vena cava approach. In a few cases, anteroseptal AP ablation may fail because of conservative energy delivery at these sites or anatomical factor. In the recent years, a few cases of successful anteroseptal AP ablation in the noncoronary cusp (NCC) or sub tricuspid annulus have been reported. However, when need to map and ablate from the NCC or sub tricuspid annulus in patients with anteroseptal APs and what will be the mapping results at the NCC in patients with anteroseptal APs successful ablated in the, right anteroseptal region (RAS) have not been well evaluated. The purpose of this study was to discuss the characteristics of surface ECG, anatomic consideration, electrophysiology, and the strategy of ablation of anteroseptal APs in order to increase the success rate and safety of radiofrequency catheter ablation. Methods There were 55 consecutive patients (age 53 ± 11 years, 36 male) out of 2200 patients presenting with anteroseptal APs who underwent RF ablation at our centre between July 2006 and March 2013. On the basis of successful ablation location, these patients were divided into right anteroseptal region group (RAS group, through inferior vena cava approach), noncoronary cusp group (NCC group, through retrograde aorta approach) and sub tricuspid annulus group (Sub-TA group, throngh superior vena cava approach). The clinical characteristics, surface electrocardiogram (ECG), intracardiac electrogram findings, and response to ablation in these patients between three groups were analysed. The strategies for mapping and ablation of anteroseptal APs were discussed. Results Successful ablation were achieved in all the 55 patients with anteroseptal APs. The sites with successful ablation were located in the RAS, adjacent to the His bundle region, in 48 patients including in 9 patients whose initial ablation were unsuccessful in the NCC. In the 4 cases with successful ablation in the NCC, the initial attempt ablation in the NCC without trying in the RAS was performed in 1 cases in whom the decision to target the NCC was based on previous experience of V-A fusion pattern adjacent to the His bundle region suggestive of an NCC AP site. In 1 of the 4 patients, irrigated energy (30–40 W and infusion rate of 17–30 ml/min) was used to eliminated the AP in the NCC after failed ablation with non-irrigated energy. There were 3 cases underwent successful ablation at Sub-TA region by a superior approach from the right internal jugular vein. There were no important complications during perioperative period. All the patients underwent a period of 8 months to 7 years of follow-up by telephone or outpatient department. Four patents ablated in RAS region recurred. No recurrence in patients underwent successful ablation in NCC or Sub-TA region. Conclusions The results of catheter ablation of anteroseptal APs in a large case series indicate that anteroseptal APs in most patients can be successful ablated in RAS region, but in a few patients, anteroseptal APs need to be ablated from the NCC or Sub-TA region. The pre-excitation characteristics have no meaningful differences among the RAS, NCC and Sub-TA group. The incidence of anteroseptal AP which had to be ablated from NCC is relatively low, so ablation from NCC was not a preferential approach. The VA fusion pattern in RAS during retrograde AP conduction may be helpful to differentiate or predict successful ablation from RAS, NCC or Sub-TA in most patients with anteroseptal AP.

GW24-e1770 Radiofrequency catheter ablation of superior ventricular tachycardia in patients with persistent left superior vena cava

Objectives Radiofrequency catheter ablation of superior ventricular tachycardia (SVT) is unusual because of the anatomy. The aim of this study is to discuss the strategy of radiofrequency catheter ablation of SVT in patients with persistent left superior vena cava (PLSVC). Methods From June 2008 to June 2011, 17 patients with PLSVC and SVT underwent one of the following RFCA: AV node modification (8 patients), left accessory pathway (6 patients), paroxysmal atrial fibrillation (3 patient). Results Coronary sinus access through left subclavian vein in each patient. AV node modification was carried out in 8 patients. Four patients with left accessory pathway were ablated through aortic retrograde approach, and the other two patients with left side accessory pathway were accomplished through transseptal approach. Three patients with PAF were cured through circumferential pulmonary vein isolation after atrium septum puncture. The success rate was 100%, and complication was not occurred. Conclusions Even though the success rate of RFCA with PLSVC and SVT was high and the complication rate was low, the recognisation of PLSVA, the skills of ablation and the precaution of complications should be payed attention.

ASSA13-02-4 Electrophysiological Characteristic and Ablation of Epicardial Idiopathic Ventricular Arrhythmias Arising Around Left Fibrous Triangle

Background The success rate of radiofrequency catheter ablation of ventricular arrhythmias originating from left fibrous triangle (LFT) is not high. This article was to discuss the characteristics of sueface electrocardiogram and the strategy of ablation of ventricular arrhythmias originating from LFT. Methods From February 2002 to March 2012, total 323 patients with outflow ventricular arrhythmias were ablated in our hospital, incluing 46 patients whose ventricular arrhythmias originated from the LFT. The mean age of the 46 patients was 44 ± 13 years (16–87 years), and 24 of them (52.2%) were male. Thirty patients had frequent premature ventricular contractions (PVCs) and 16 patients had both PVCs and nonsustained or sustained ventricular tachycardia (VT). All the patients were examined with ECG, electrophysiology, active mapping and pace mapping. The computer tomography angiogram (CTA) 3D reconstruction of coronary artery, venouswas completed in 20 patients. Results Successful ablation was achieved in 41 of the 46 patients (89.1%, 41/46) targeting left coronary cusp (LCC, 30 patients), infra aortic valve (infra AV, 6 patients) and great cardiac vein (GCV, 5 patients). The surface ECG in all the three groups presented with inferior axis and R/S-transition in lead V1 and V2. There were no differentces in the total QRS duration in the three groups. Most of the patients presented with right bundle branch block (RBBB) morphology in infra AV group and GCV group compared with LCC group (67%, 80% vs 15%, P = 0.002). Regarding to the classification of the LFT according to CTA, the patterns of distribution were as follows: “closed” in 10 (50%, 10/20) hearts; “completely opened” in 2 (10%, 2/20); “inferiorly opened” in 5 (25%, 5/20) hearts and “superiorly opened” in 1 (5%, 1/20) hearts. In the remaining 2 (10%, 2/20), there were not any distances between cardiac vein and artery. The closest distance between the corner of the GCV and LCC is 17.6 ± 4.2 mm (9.1mm ∼ 26.3mm). Conclusions Ventricular arrhythmias originating from the LFT can be ablated in the nadir of the LCC, infra AV and the GCV. The success rate may be impacted by the distance from the GCV and the LCC.

ASSA13-02-8 Safety, Efficacy and Learning Curve of Catheter Ablation of Paroxysmal Atrial Fibrillation Using Circumferential Pulmonary Vein Isolation Technique in the Single Centre and in a Single Operator

Background CARTO anatomical mapping system and circumferential pulmonary vein isolation (CPVI) technique has been used to cure paroxysmal atrial fibrillation (PAF) in most hospitals in China, and have achieved a high success rate. But whether the successful rate, the recurrence rate and the safety are related to learning cure is still unclear. Methods From December 2004 to December 2010, 258 consecutive patients who underwent CPVI for PAF in our hospital were collected. The patients were divided into three groups with equal patient numbers according to the time sequences. Group I consisted of the first 86 cases, Group II consisted of the second 86 patients, and Group III consisted of the last 86 cases. Age, gender, course of disease, echocardiography, other atrial arrhythmias, basic diseases were analysed statistically. The operation X-ray exposure time, recent recurrence, late recurrence and re-ablation procedures were also analysed. In addition, the learning curve of CPVI for PAF and its relationship with peri-operative period complications, and the risk factors to predict the recurrence of atrial arrhythmias were analysed, too. Results There were no significant differences in patients’ age, gender, basic diseases and LAD among three groups. The rates of early recurrence in Group I, Group II and Group III were 38/86 (44.2%), 26/86 (30.2%) and 21/86 (24.4%) respectively (P < 0.05). The successful rates at 1 year were 44.2%, 51.2%, 64.0% respectively (P < 0.05) in three groups. The incidence of general complications was 12.8% in Group I, 4.7% in Group II, and 2.3% in group III. There were statistically significant differences between the total complication rates among the three groups. In many variables, left atrium dimension (LAD) enlargement and early recurrence were the risk factors of recurrent AF (P < 0.01 and P < 0.05, respectively). Conclusion For an experienced operator, CPVI has a higher success rate, a lower recurrence and a lower complication rate for radiofrequency catheter ablation of PAF. However, for a beginning operator, the success rate was relatively lower, both the recurrence and the complication rate were higher, and the X-ray exposure time was longer. The strengthened training of CPVI technique for PAF may be very important for the new operator to increase the success and to avoid or decrease the incidence of complications.