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.

Efficacy and safety of a novel multi-electrode radiofrequency ablation catheter for renal sympathetic denervation in pigs

Objective To investigate the safety and efficacy of a self-developed novel multi-electrode radiofrequency ablation catheter （Spark） for catheter-based renal denervation （RDN）. Methods A total of 14 experimental miniature pigs were randomly divided into four groups （55°＆ 5-watt, 55°＆ 8-watt, 65°＆ 5-watt, and 65° ＆ 8-watt groups）. Spark was used for left and right renal artery radiofrequency ablation. Blood samples collected from renal arteries and veins as well as renal arteriography were performed on all animals before, immediately after, and three months after procedure to evaluate the effects of Spark on the levels of plasma renin, aldosterone, angiotensin I, and angiotensin II as well as the pathological changes of renal arteries. Results One pig died of an anesthetic accident, 13 pigs successfully underwent the bilateral renal artery ablation. Compared with basic measurements, pigs in all the four groups had significantly decreased mean arterial pres- sure after procedure. Histopathological analysis showed that this procedure could result in intimal hyperplasia, significant peripheral sympa- thetic nerve damage in the renal arteries such as inflammatory cell infiltration and fibrosis in perineurium, uneven distribution of nerve fibers, tissue necrosis, severe vacuolization, fTagmented and unclear nucleoli myelin degeneration, sparse axons, and interruption of continuity. In addition, the renal artery radiofrequency ablation could significantly reduce the levels of plasma renin, aldosterone, angiotensin I, and angio- tensin II in pigs. Conclusions The results suggest that this type of multi-electrode catheter-based radiofrequency ablation could effectively remove peripheral renal sympathetic nerves and reduce the activity of systemic renin-angiotensin system in pigs, thus facilitating the control of systemic blood pressure in pigs.

Radiofrequency catheter ablation of atrial tachycardias related to myocardial scar or incision

Objectives Intra-atrial re-entrant tachycardias(IARTs)are common late after heart surgery.Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops.In this study we aimed to evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia(AT)induced by myocardial scar or incision.Methods In 6 patients(three male and three female,aged 33.3±11.8 years)who had AT related to myocardial scar or incision, electrophysiological study and radiofrequency catheter ablation(RFCA)were performed.Earliest activation combined with entrain- ment mapping was adopted to determine a critical isthmus.Results Re-entry related to the lateral atriotomy scar was inducible in 5 of 6 patients.With entrainment mapping,the PPI(post-pacing interval)-TCL(tachycardia cycle length)difference was＜30 ms when pacing at the inferior margins of the right lateral atriotomy scar.Among them,3 patients had successful linear ablation between scar area to inferior vena cava,and 2 patients between scar area to tricuspid annulus.Re-entry involving an ASD patch was demonstrated in 1 of 6 patients.PPI-TCL differences＜30 ms were observed 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 AT related to incision was observed during follow-up except for the failed patient.Conclusion Under conventional electrophysiological mapping,adopting linear ablation from scar area to anatomic barrier,successful ablation can be obtained in patients with IRATs related to myocardial scar or incision.

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.

Radiofrequency Catheter Ablation Of Inappropriate Sinus Tachycardia

Objective:To investigate the mechanism of inappropriate sinustachycardia and the safety,effectiveness on radiofrequency catheterablation of it.Methods:Radiofrequency catheter ablation wasperformed on a 52-year-old female patient and changes in Holter,heart rate variability,intrinsic heart rate and syndromes were comparedbetween before and after radiofrequeney catheter ablation.Results:The inappropriate sinus tachycardia could not be induced and terminatedby atrial program electric stimulation and burst stimulation,whichsuggests that the mechanism of inappropriate sinus tachycardia isreentry.After radiofrequency catheter ablation,the total heart beatsdecreased from 173490 to 129172 times,the lowest heart rate did from79 to 71 bpm,the highest heart rate from 200 to 122 bpm,the averageheart rate from 117 to 90 bpm,and intrinsic heart rate from 166 to 93Variables of heart rate variability varied too.PNN50 increased from O to11,RMSSD did from 8 to 35.However,LF/HF ratio decreased from12.23 to 0.86.Transesophageal eleetrophysiologic studies demonstratethat sinoatrial node function is normal after radioflequency catheterablation.The patient has been followed up for six months,she has beenbeing free of palpitation,chest distress and dizziness,etc.Conclusion:The inappropriate sinus tachycardia could be due to abnormal sinoatrialnodal automaticity resulting from excessive sympathetic nerve influencesor deficient vagal nerve influences and modification of sinus node withradiofrequency catheter ablation is a safe,effective method for thetreatment of inappropriate sinus tacbycardia.

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.

Role of a new inflammation predictor in predicting recurrence of atrial fibrillation after radiofrequency catheter ablation

BACKGROUND Radiofrequency catheter ablation(RFCA)has become an important strategy for treating atrial fibrillation(AF),and postoperative recurrence represents a significant and actively discussed clinical concern.The recurrence after RFCA is considered closely related to inflammation.Systemic immune inflammation index(SII)is a novel inflammation predictor based on neutrophils,platelets,and lymphocytes,and is considered a biomarker that comprehensively reflects the immune inflammatory status of the body.AIM To explore the predictive effect of the SII on AF recurrence after RFCA and its predictive value in combination with the existing APPLE score for AF recurrence after RFCA in patients with non-valvular AF(NVAF).METHODS We retrospectively included 457 patients with NVAF first receiving RFCA and classified them into the recurrent or non-recurrent group.We also investigated the predictive role of SII on AF recurrence following RFCA.Finally,we explored and compared the additional predictive value of the SII after combining with the APPLE score.RESULTS After 12 months of follow-up,113(24.7%)patients experienced recurrence.High SII has been demonstrated to be an independent predictor for postoperative AF recurrence.Receiver operating characteristic and decision curve analysis(DCA),as well as net reclassification improvement(NRI)and integrated discrimination improvement(IDI)results,showed that SII combined with the APPLE score had higher predictive efficiency than using the SII or APPLE score alone.The area under the curve of the combined model(0.662,95%confidence interval:0.602-0.722)significantly increased compared with that of the SII and APPLE scores alone(P<0.001).The combined model resulted in an NRI of 29.6%and 34.1%and IDI of 4.9%and 3.5%in predicting AF recurrence compared with the SII and APPLE scores alone,respectively(all P<0.001).The SII,APPLE score,and their combination demonstrated greater clinical utility than did the treat-all and treat-none strategies over the 20–80%risk threshold according to the DCA.CONCLUSION The SII was a predictor of recurrence after RFCA of AF.Moreover,the SII enhanced the predictability of the APPLE score for post-RFCA AF recurrence,providing valuable insights for physicians to optimise patient selection and develop personalised treatment plans.

Design and Baseline Patient Characteristics of the Prospective, Observational, Multicenter and Multinational Cohort Study Comparing Radiofrequency with Cryoablation for Pulmonary Vein Isolation in Patients with Atrial Fibrillation—The Freeze Cohort Study

Aims: The FREEZE-cohort study (NCT 01360008) is a prospective observational, multicenter and multinational study to evaluate safety and effectiveness of cryoballoon ablation for pulmonary vein isolation as compared to radiofrequency ablation in patients with paroxysmal or persistent atrial fibrillation (lasting < one year) under the conditions of clinical routine. Methods and Results: The study started in 2011 and anticipates inclusion up to 2000 patients in each of the two treatment groups. A total of 37 centers from 8 countries worldwide, all experienced in at least one of the two ablation techniques, participate in the study. The primary outcome parameter of the study is defined as atrial fibrillation recurrence rate during twelve months of follow-up. Secondary outcome parameters include primary success rates, complication rates in general, specific complications with respect to phrenic nerve palsy and pulmonary vein stenosis, radiation exposure, clinical course including death and repeat ablation. Finally specific procedural aspects will be evaluated in a descriptive manner. Preliminary data of the first 1882 patients show that in clinical practice cryoablation is preferentially performed in patients with paroxysmal atrial fibrillation, whereas application of radiofrequency ablation is equally distributed between patients with persistent and paroxysmal atrial fibrillation. Conclusion: Based on multi-center and multi-national data the FREEZE-cohort study will provide important information on long-term efficacy, clinical effectiveness, complication rates and procedural differences between atrial fibrillation patients treated with either cryoablation or radiofrequency ablation.

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.

Role of catheter ablation of ventricular tachycardia associated with structural heart disease

In patients with structural heart disease, ventricular tachycardia (VT) worsens the clinical condition and may severely affect the shortand long-term prognosis. Several therapeutic options can be considered for the management of this arrhythmia. Among others, catheter ablation, a closed-chest therapy, can prevent arrhythmia recurrences by abolishing the arrhythmogenic substrate. Over the last two decades, different techniques have been developed for an effective approach to both tolerated and untolerated VTs. The clinical outcome of patients undergoing ablation has been evaluated in multiple studies. This editorial gives an overview of the role, methodology, clinical outcome and innovative approaches in catheter ablation of VT.

RADIOFREQUENCY CATHTER ABLATION IN MANAGEMENT OF A GERONTAL PATIENT WITH PERMANENT JUNCTION RECIPROCATING TACHYCARDIA

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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.

HRV changes before and after radiofrequency ablation in patients with different origin of right ventricular outflow tract ventricular premature contraction

Objective:To observe the HRV changes before and after the radiofrequency current catheter ablationventricular premature beats originated from different site of right ventricular outflow tract.Methods:A total of 102 patients with frequent RVOT-VPC admitted to our hospital were accepted radiofrequency current catheter ablation (RF). According to the origin of RVOT-VPC, it was divided into 2 groups, one is from ventricular septum, and the other one is from free wall, and in each group, male and female are observed separately.Results:(1) HRV before RF ablation: 1) rMSSD in the female patients with RVOT-VPC from free wall was significantly lower than those from septum;2) frequency domain index (W, LF) were higher than normal range, and in male patients, LF/HF<1 were found, but in female patients, LF/HF>1. (2) HRV after RF ablation: 1) Significant changes were found in female patients with RVOT-VPC from septum, rMSSD, PNN50, HF and LF decreased;2) In female patients with RVOT-VPC from free wall, rMSSD decreased;3) In male patients, there were no significant HRV changes found before and after RF ablation. (3) Heart rate changes: 1) In female patients with RVOT-VPC from septum, heart rate decreased significantly ((76.47±9.47) bpm vs (69.29±14.59) bpm)2) No significant changes were found in male patients.Conclusion:In patients with RVOT-PVC sympathetic and vagus excitability increased, and after catheter ablation, in female patients with RVOT-PVC originated from septum, the HRV index relating to sympathetic and vagus excitability significantly decreased.

Catheter ablation using pulsed-field energy:Do we finally have the magic wand to defeat atrial fibrillation?

Clinical outcomes of catheter ablation remain suboptimal in patients with atrial fibrillation(AF),particularly in those with persistent AF,despite decades of research,clinical trials,and technological advancements.Recently,pulsed-field ablation(PFA),a promising non-thermal technology,has been introduced to improve procedural outcomes.Its unique feature of myocardial selectivity offers safety advantages by avoiding potential harm to vulnerable adjacent structures during AF ablation.However,despite the global enthusiasm within the electro-physiology community,recent data indicate that PFA is still far from being a“magic wand”for addressing such a complex and challenging arrhythmia as AF.More progress is needed in mapping processes rather than in ablation technology.This editorial reviews relevant available data and explores future research directions for PFA.

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

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.