Clinical Study on the Treatment of 325 Cases of Atrioventricular Node Reentrant Tachycardia by Radiofrequency Catheter Ablation

In order to improve the efficacy of modified inferior method or middle method of radiofrequency catheter ablation (RFCA) in the treatment of atrioventricular node reentrant tachycardia (AVNRT), the clinical data of 325 cases of AVNRT from March 1992 to Feb. 2000 being subjected to the treatment of RFCA were retrospectively analyzed. The results showed that the successful rate was increased and recurrence was decreased year by year. In the recent 4 years the effective rate was up to 100 %. The complication of three grade of AVB occurred in 3 % and recurrent rate in 9.1 % before March 1996, but both of them were zero in the last 3 years. The time of RFCA procedure and X ray exposure was significantly reduced. It was concluded that ablating more than 3 targets by modified inferior method or middle method with energy titrating and strict endpoint was the crux of obtaining satisfactory therapeutic effects and preventing recurrence.

RADIOFREQUENCY CATHETER ABLATION OF PERMANENT ATRIAL FIBRILLATION UNDER GUIDANCE OF CARTO-MERGE TECHNIQUE

Objective To investigate the feasibility and effectiveness of radiofrequency catheter ablation (RFCA) to treat permanent atrial fibrillation (AF) under the guidance of Carto-Merge technique. Methods Fifteen male patients with permanent AF underwent RFCA under the guidance of Carto-Merge technique. The mean age was 54.00±10.44 years, and duration of AF was 23.66±14.93 months. Cardiac magnetic resonance angiography (MRA) was performed to obtain pre-procedural three-dimensional (3D) images on the anatomy of left atrium (LA) and pulmonary veins (PVs) before RFCA procedure. Then the electroanatomical map was integrated with 3D images of MRA to form Carto-Merge map that guided step-by-step ablation strategy of permanent AF. Circumferential PV ablation was performed first until complete PVs electric isolation confirmed by Lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced. Results The episodes of AF were terminated during RFCA in 2 patients, by direct current cardioversion in the remaining 13 patients. Transient AF occurred in 2 patients after ablation on 1st day and 1st week respectively, AF terminated spontaneously not long after taking metoprolol. One patient developed persistent atrial flutter (AFL) in 2 months after procedure and AFL was eliminated by the second ablation. Persistent AF recurred on 1st day, 1st and 5th week respectively in 3 patients, and did not terminate after 3 months even though amiodarone was given. The remaining 12 patients were all free of AF during 2-11 months of follow-up. The recent success rate for RFCA of permanent AF was 80%. Conclusions Carto-Merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping, lower expenses, and enhance the success rate of RFCA of permanent AF.

Delayed papillary muscle rupture after radiofrequency catheter ablation: A case report

BACKGROUND With an increased number of surgical procedures involving the mitral annular region,the risk of mitral valve prolapse(MVP)has also increased.Previous studies have reported that worsening of MVP occurred early after radiofrequency catheter ablation(RFCA)at papillary muscles in ventricular tachycardia(VT)patients with preoperative MVP.CASE SUMMARY We report a case where MVP and papillary muscle rupture occurred 2 wk after RFCA in a papillary muscle originated VT patient without mitral valve regurgitation or prolapse before.The patient then underwent mitral valve replacement with no premature ventricular contraction or VT.During the surgery,a papillary muscle rupture was identified.Pathological examination showed necrosis of the papillary muscle.The patient recovered after mitral valve replacement.CONCLUSION Too many ablation procedures and energy should be avoided.

The correlation between MFAP4 and recurrence and clinical outcome of atrial fibrillation after radiofrequency catheter ablation

Objective:To investigate the correlation between Microfibrillar-associated protein 4(MFAP4)and recurrence and clinical outcome of atrial fibrillation(AF)after radiofrequency catheter ablation(RFCA).Methods:A total of 101 patients with AF admitted to our department from December 2018 to January 2020 were treated with RFCA.The average follow-up period was(11.91±0.38)months.They were divided into recurrence group and non-recurrence group according to whether they had recurrence of AF.The levels of MFAP4,transforming growth factor-β1(TGF-β1),cardiac ultrasound indexes,body mass index(BMI)and major cardio-cerebral vascular events were compared between the two groups.The receiver operating characteristic(ROC)curve was drawn to analyze the predictive value of MFAP4 for recurrence of AF after RFCA.Results:The levels of MFAP4,TGF-β1,left atrial diameter(LAD)and BMI in the recurrent group were higher than those in the non-recurrent group(P<0.05).The left ventricular ejection fraction(LVEF)in the recurrent group was lower than that in the non-recurrent group(P<0.05).The levels of MFAP4,TGF-β1 and LAD in the patients of recurrent paroxysmal AF and persistent AF after RFCA were higher than those in the respective non-recurrent patients(P<0.05).MFAP4 was positively correlated with TGF-β1 and LAD(P<0.05).Logistic regression analysis showed that MFAP4,TGF-β1,and LAD were independent risk factors for recurrence of AF after RFCA.The ROC curve analysis showed that the area under the ROC curve of MFAP4 for predicting recurrence of AF after RFCA was 0.888(P=0.000),and the optimal cut-off value was 19.295ng/ml,with a sensitivity of 77.3%and a specificity of 77.2%.The incidence of readmission and total adverse events in recurrence group was significantly higher than that in non-recurrence group(P<0.05).Conclusions:MFAP4 was significantly increased in patients with recurrence after RFCA of AF,which was one of the independent risk factors for recurrence after RFCA of AF,and had certain clinical application value.

Needle track seeding:A real hazard after percutaneous radiofrequency ablation for colorectal liver metastasis

Neoplastic needle track seeding following percutaneous radiofrequency ablation(RFA)of secondary liver tumors is exceedingly rare.Reports on cutaneous tumor seeding after percutaneous RFA for colorectal liver metastasis are even rarer in the literature.Here we report a case of a 46-year-old female who developed an ulcerating skin lesion along the needle track of a previous percutaneous RFA site around 6 mo after the procedure.The previous RFA was performed by the LeVeen needle for a secondary liver tumor from a primary rectal cancer.The diagnosis of secondary skin metastasis was confirmed by fine needle aspiration cytology.The lesion was successfully treated with wide local excision.We believe that tumor seeding after percutaneous RFA in our patient was possibly related to its unfavorable subcapsular location and the use of an expansion-type needle.Hence,prophylactic ablation of the needle track should be performed whenever possible.Otherwise,alternative routes of tumor ablation such as laparoscopic or open RFA should be considered.

Catheter ablation of premature ventricular complexes associated with false tendons: A case report

BACKGROUND False tendon is a common intraventricular anatomical variation. It refers to a fibroid or fibromuscular structure that exists in the ventricle besides the normal connection of papillary muscle and mitral or tricuspid valve. A large number of clinical studies have suggested that there is a significant correlation between false tendons and premature ventricular complexes. However, few studies have verified this correlation during radiofrequency catheter ablation of premature ventricular complexes.CASE SUMMARY A 45-year-old male was admitted to receive radiofrequency ablation for symptomatic premature ventricular complexes. A three-dimensional model of the left ventricle was established by intracardiac echocardiography using the CartoSound^TM mapping system. In addition to the left anterior papillary muscle,the posterior papillary muscle was mapped. False tendons were found at the base of the interventricular septum, and the other end was connected to the left ventricular free wall near the apex. An irrigated touch force catheter was advanced into the left ventricle via the retrograde approach. The earliest activation site was marked at the interventricular septum attachment of the false tendons and was successfully ablated.CONCLUSION This case verified that false tendons can cause premature ventricular complexes and may be cured by radiofrequency ablation guided by intracardiac echocardiography with the Carto Sound TM system.

Radiofrequency ablation of atrial tachycardia in patients with repaired atrial septal defect

Objective:To evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) in patients with repaired atrial septal defects(ASD). Methods: In 76 consecutive patients with AT who underwent the electrophysiological study and radiofrequency catheter ablation (RFCA). 4 patients (one male and three female aged 35. 5±11. 5 years) had AT-related myocardial scar or incision. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus. Results: Re-entry related to the lateral atriotomy scar was inducible in 3 of 4 patients. With en-trainment mapping, the PPI-TCL difference was <30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 2 patients had successful linear ablation between scar area to inferior vena cava, and 1 patient between scar areas to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 4 patients. PPI-TCL differences <30 ms were found when entraining tachycardia at sites near the septal patch. But linear ablation failed in terminating AT. There was no complication during procedure. No recurrence of incision-related AT was found during follow-up except for the failed patient. Conclusion: Under conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation also can be obtained in patients with IRAT related to myocardial scar or incision.

The Experience of Radiofrequency Ablation for Treatment of Multiple Accessory Pathways

Objective To analyse retrospectively the experience of radiofrequency ablation for successful treatment of multiple accessory pathways (APS). Methods 150 patients with supraventricu-lar tachycardia related to APS have undergone radiofrequency ablation since 1994; the data was analysed. Results 8 patients with multiple APS were cured, 4 patients could be diagnosed to have multiple APS during electrophysiologic study (EPS) before ablation, and in the remaining 4 patients the multiple APS could only be diagnosed after successful ablation of one AP. Conclusion right - sided multiple APS are sometimes very difficult to treat by ablation, because there are no standard reference electrograms for bracketing the earliest site. Mapping area should be broader rather than limited by preestablished idea.

A three-year longitudinal study of the relation between left atrial diameter remodeling and atrial fibrillation ablation outcome

Background The long-term prognostic influence of left atrial diameter （LAD） remodeling on the status of post-radiofrequency catheter ablation （RI CA） atrial fibrillation （AF） is unclear. This study employed a two-stage model from 3-year echocardiographic data to ascertain whether the two-stage model predicts RFCA outcome more favorably than models using the baseline LAD. Methods Data were retrospectively collected from 263 consecutive patients with drug-refractory AF undergoing RFCA. Regular echocardiographic measurements of LAD were performed at baseline, 1, 3, 6, and 12 months and then every 6 months after RFCA. Sex, age, type of AF, number of RFCA, and AF status were recorded. We obtain the actual （predicted） 3-year LAD using a longitudinal linear mixed model （1st stage）. Logistic regression models based on the baseline LAD （Model 1）, actual （predicted） 3-year LAD （Model 2） （2nd stage）, and observed 3-year LAD （Model 3） were constructed to predict RFCA outcome. The area under the receiver operating characteristic curve （AUC） were used to assess the performance of models. Results The lowess smoothed curve indicated that the LAD declined over the first three months and remained stable up to 36 months after RFCA. The degree of LAD reduction was significantly influenced by the baseline LAD. Non-paroxysmal AF, large LAD and female gender were significant predictors of AF recurrence. Model 2 had the largest AUC among the three models. Conclusions This longitudinal study-based two-stage model outperforms the original logistic model using the baseline LAD. Non-paroxysmal AF, larger LAD and female gender are significant predictors of RFCA failure.

Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia guided by magnetic navigation system： a prospective randomized comparison with conventional procedure

Background Atrioventricular nodal reentrant tachycardia （AVNRT） is one of the most common paroxysmal supraventricular tachyarrhythmias. The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure. Methods Patients with AVNRT diagnosed by electrophysiological tests were randomized into two groups. In the conventional technique group （CMT）, a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group （MNS）, a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. The following parameters were collected and compared between the two groups： ablation procedure time, patient fluoroscopy time, operator fluoroscopy time, energy delivery numbers, maximal energy per deployment, success rate, complication rate and operative cost. Results Forty patients were enrolled and randomized into CMT and MNS groups. The age, gender, tachycardia history and basic cardiovascular diseases of the two groups were comparable （P 〉0.05）. All procedures were conducted successfully without complications. No tachycardia recurred during the follow-up period of （9.3±2.6） months. In the MNS group, the patient and operator fluoroscopy times （（11.5±4.3） min, （4.2±1.5） min）, energy delivery numbers （3.2_＋0.9）, and maximal energy per deployment （16.9±3.4） W） were shorter or lower than those of the CMT group （（14.3±6.2） min, （13.6±3.5） min, 6.3±2.1, （23.7±1.3） W, respectively） （P 〈0.05）. But the operative cost for the MNS group was higher than that of the CMT group （P 〈0.01 ）. Conclusion Magnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.

Radiofrequency catheter ablation of idiopathic ventricular tachycardia and symptomatic premature ventricular contraction originating from valve annulus

Background Radiofrequency catheter ablation （RFCA） has been established as an effective and curative therapy for ventricular tachycardia （VT） and severely symptomatic premature ventricular contraction （PVC） from the outflow tract in structurally normal hearts. This study aimed to investigate electrophysiologic characteristics and effects of RFCA for patients with idiopathic VT and symptomatic PVC originating from the valve annulus. Methods Characteristics of body surface electrocardiogram （ECG） and endocardiogram in a successful RFCA target were analyzed in 16 patients with idiopathic VT and symptomatic PVC originating from the valve annulus. Additionally, the ECG characteristics of VT or PVC were compared with those of manifest Wolff-Parkinson-White （WPW） syndrome originating from the same site of origin in 15 patients. Results Thirteen patients were successful, 2 recurrent and 1 failed. The recurrent cases underwent successful ablation the second time guided by the Ensite 3000 mapping system. In all patients with the WPW syndrome, the characteristics of QRS morphology were well matched with those of the VT and PVC that originated from corresponding sites of origin. Conclusions RFCA is an effective curative therapy for VT and There are specific characteristics in ECG and the ablation site accessory pathway＇s algorithm. symptomatic PVC originating from the valve annulus. could be located by means of the WPW syndrome

Metabolic benefits of rivaroxaban in non-valvular atrial fibrillation patients after radiofrequency catheter ablation

Background and objective： Rivaroxaban is a new oral anticoagulant for stroke prevention in patients with non-valvular atrial fibrillation （NVAF）, which has less drug-food interaction than warfarin. We conducted this pro- spective randomized study to evaluate the metabolic benefits as well as the safety and efficacy with rivaroxaban versus warfarin in patients with NVAF following radiofrequency catheter ablation （RFCA）. Methods： From April to July 2014, 60 patients with NVAF undergoing RFCA were prospectively enrolled in our study. Following RFCA, all patients were randomly assigned to receive rivaroxaban （Group R, n=30） or warfarin （Group W, n=30）. Metabolic indices including serum total protein, albumin, globulin, and high-density lipoprotein （HDL） as well as bleeding, stroke, and systemic thromboembolism events were evaluated and compared during follow-up after 15, 30, 60, and 90 d of RFCA procedure. Results： Serum total protein, albumin, globulin, and HDL levels were all significantly elevated at each follow-up stage in Group R when compared to the baseline （P〈0.05 respectively）. In Group W, the metabolic indices decreased at first and then had an increasing trend. There were no deaths or thromboembolic complications in each group. The prevalence of total bleeding complications was similar between Group R and Group W （11/30, 36.7% vs. 10/30, 33.3%, P=0.70）. Conclusions： Patients with NVAF receiving rivaroxaban after RFCA procedures appear to benefit from a metabolic perspective compared with warfarin, providing practical clinical reference for the choice of the anticoagulant. Rivaroxaban seems to be as safe and effective in preventing thromboembolic events as warfarin for these patients.

RADIOFREQUENCY CATHETER ABLATION OF VENTRICULAR TACHYCARDIA IN 26 PATIENTS

Electrophysiology study and radiofrequency catheter ablation (RFCA) were performed in 26 patients with refractory sustained ventricular tachycardia (VT). After induction of VT, 12-lead electrocardiogram (ECG) was recorded and QRS morphology and axis of induced VT were studied to identify the origin of VT. The precise site of VT origin were localized by pace mapping and activation mapping carefully. RF energy was delivered through a big-tip deflectable electrode catheter when the earliest site of endocardial activation and a high-frequency and low-amplitude potential of Purkinje fiber, preceding surface QRS by more than 25 ms, were identified and / or a pace map was obtained showing identical QRS complexes in at least 11 of 12 ECG leads. VTs were ablated successfully in 24 of 26 patients (success rate was 92%). For successful ablation, it is essential that the pace map QRS morphology in 12 leads should be identical with that in spontaneous or induced VT as far as possible in performing pace mapping. Pace mapping is safe, simple and has no unfavourable effect on hemodynamics although it takes longer time. Activation mapping takes shorter time and has a high success rate. QRS configuration in spontaneous VT can help to localize the site of VT origin. Deliberate mapping at the site suggested to bo the origin of VT by surface ECG can shorten the duration of mapping and increase the success rate of RFCA. RFCA of VT in patients without structural heart disease is effective, safe, and has a high success rate, so it may be considered as an early therapy for these patients.

Right phrenic injury after radiofrequency catheter ablation of atrial tachycardia at crista terminalis

A 62-year-old woman with frequent occurrence of symptomatic atrial tachycardia with a foci located at the root of the upper crista terminalis was found to have right diaphragm paresis after receiving a total of 8 radiofrequency energy deliveries （40-60 W, 50-60℃） and a total duration of 540 seconds of ablation therapy （7Fr 8 mm deflectable ablation catheter）. The right diaphragm paresis remained resolved up to 14 months after the procedure as confirmed by repeated chest X-rays.

A study of histochemistry on response of ventricular myocardium to radiofrequency catheter ablation

Abstract Using histochemistry technique, the effects of radiofrequency catheter ablation (RFCA) on the activities of LDH, SDH, CCO, and Ca^2+ ATPase of guinea pig ventricular myocytes were examined. In the meanwhile, the histological changes were observed as Department of Cardiology, Tongji Hospital, Tongji Medical University. Wuhan 430030, China (Wang YG, Lu ZY) Department of Anatomy, Tongji Medical University, Wuhan 430030, China (Xiong XK) control. Radiofreqency energy (500 kHz) delivered was 20W×10s. The resultes were as follows: RFCA resulted in significant impairments in all the four kinds of enzymses but without statistical differences among their areas involved in this energy level, and there are no statistical significant differences when compared with those of histological lesion area. These findings showed consistency in areas of the histological and histochemical lesions resulted from RFCA.

Effect of Accessory Pathway Conduction on PJ Interval in Wolff-Parkinson-White Syndrome

Objective To observe the effect of accessory pathway (AP) conduction on PJ interval in patients with Wolff-Parkinson-White syndrome. Methods 129 patients with a single manifestation of AP who underwent successful radiofrequency ablation (RFCA) were included. Patients were divided into 10 groups according to AP location. The PR intervals, QRS durations and the PJ intervals were measured using simultaneous 12-lead ECG before and after ablation. The PJ intervals before ablation were compared with that after ablation. The atrioventricular (AV) conduction time via atrioventricular node-His conduction system before ablation were compared with the PR intervals after ablation. The ventricular depolarization time via atrioventricular node-His conduction system before ablation were compared with the QRS durations after ablation. Delta waves were compared between each two groups. Results (1) The PJ intervals of right posterior (RP) group and right posteroseptal (RPS) group before ablation were shorter than that after ablation (RP group 226±18 ms vs 236±19 ms, P<0.01, RPS group 221±18 ms vs 238±31 ms, P<0.05, respectively). (2) There were no significant differences between the atrioventricular (AV) conduction time via atrioventricular node-His conduction system before ablation and the PR intervals after ablation. (3)The ventricular depolarization time via atrioventricular node-His conduction system of RP group and RPS group before ablation were shorter than the PR intervals after ablation(RP group 79±12 ms vs 87±9 ms, P=0.01; RPS group 70±13 ms vs 86±9 ms, P<0.05, respectively). (4)The delta waves of RP group and RPS group were longer than that of left posterior group and left posteroseptal group(P<0.05). Conclusion PJ interval is shortened by AP conduction which pre-excites the general last excited part of left ventricle. It is determined by AP location and the extent of preexcitation.

Radiofrequency ablation for treating paroxysmal supraventricular tachycardia complicated by atrial fibrillation： A single-center retrospective analysis

The effect of selective radiofrequency ablation for treating paroxysmal supraventricular tachycardia （PSVT） and its associated paroxysmal atrial fibrillation （PAF） was assessed. Methods Data were collected retrospectively from patients diagnosed of PSVT and subsequently treated with radiofrequency ablation. Regular monthly follow-up by dynamic electrocardiography （ECG） was performed. Incident rates of atrial fibrillation before and after ablation were compared. Results 382 PSVT patients with 58 having atrial fibrillation were en- rolled. The order of complicated PAF from high to low in these patients was displayed as： atrial tachycardia （AT）, atrioventricular reentrant tachycardia （AVRT） and atrioventricular nodal reentrant tachycardia （AVNRT）. Among AVRT patients, PAF was more frequent in patients having accessory pathways. AVNRT patients had significant- ly lower PAF rate comparing to other patients. PAF incident rate was significantly reduced by radiofrequency ablation therapy. Conclusion We advise regular dynamic ECG for PSVT patients, especially those with atrial flutter, AT or pre-excitation syndrome. Selective radiofrequency ablation is a feasible approach for treating AF complicated PSVT patients.

The automaticity of Mahaim fibre and its response to effective ablation

Background Typical accessory pathways (APs) of Wolf Parkinson White syndrome have been widely discussed in recent decades However, the characteristics of the special AP, Mahaim fibre, are not so clear It is known that these fibres have antegrade conduction only, long conduction time, decremental node like conduction and automaticity properties This study was to elucidate the automaticity of Mahaim fibre and its response to effective ablation Methods Thirteen patients with Mahaim fibre (ten atrioventricular and three atriofascicular accessory pathways) were subjected to electrophysiological study and radiofrequency ablation via catheter The incidence and characteristics of anautomatic rhythm originating from Mahaim fibre were observed during the whole procedure, especially during radiofrequency current delivery Results Repetitive and short run automatic rhythm (rate: 65-72 beats per minute), with a QRS morphology similar to that of clinical pre excited atrioventricular re entrant tachycardia (AVRT), occurred in two patients during sinus rhythm Conduction via Mahaim fibre was successfully eliminated by radiofrequency current Fourteen applications of RF were associated with irregularly accelerated automatic tachycardia of Mahaim fibre (with a sensitivity of 78%), lasting for 1 2-14 seconds However, such automatic tachycardia of Mahaim fibre did not occur during 54 failed applications of radiofrequency current Conclusions Mahaim fibre has the function of automaticity The accelerated automatic tachycardia of Mahaim fibre occur red during radiofrequency catheter ablation can be used as a predictor for successful procedure