Severe hypoxemia after radiofrequency ablation for atrial fibrillation in palliatively repaired tetralogy of Fallot: A case report

BACKGROUND Patients with tetralogy of Fallot(TOF)often have arrhythmias,commonly being atrial fibrillation(AF).Radiofrequency ablation is an effective treatment for AF and does not usually cause severe postoperative hypoxemia,but the risk of complications may increase in patients with conditions such as TOF.CASE SUMMARY We report a young male patient with a history of TOF repair who developed severe hypoxemia after radiofrequency ablation for AF and was ultimately confirmed to have a new right-to-left shunt.The patient subsequently underwent atrial septal occlusion and eventually recovered.CONCLUSION Radiofrequency ablation may cause iatrogenic atrial septal injury;thus possible complications should be predicted in order to ensure successful treatment and patient safety.

Catheter ablation of atrial fibrillation in elderly population

Background Although elderly patients have been included in published series of catheter ablation for atrial fibrillation （AF）, clinicalbenefit and safety remain still less defined in this population. A retrospective analysis of the results of catheter ablation for AF in a large volumecenter focused on comparison of elderly patients with the rest of the patient cohort was conducted in this study. Methods Consecutive patientswho underwent catheter ablation for AF between January 2001 and December 2016 were analysed. A total population of 3197 patients wasdichotomized by the age of 70 years （394 elderly vs. 2803 younger subjects）. Patients were followed in terms of arrhythmia status and sur-vival for a median period of 18 vs. 21 and 35 vs. 57 months, respectively. Results Elderly patients were more frequently females （49% vs.29%, P 〈 0.0001）, had a history of hypertension （79% vs. 57%, P 〈 0.0001）, diabetes （16% vs. 11%, P 〈 0.01）, stroke （9% vs. 6%, P 〈 0.01）,coronary/peripheral artery disease （14% vs. 8%, P 〈 0.0001）, and CHAzDS2-VASc score （3.1 ± 1.3 vs. 1.5 ± 1.2 s, P 〈 0.0001）. Major com-plications were more frequent in elderly （5.3% vs. 3.2%, P = 0.03）; however, this difference was driven by vascular complications （3.6% vs.1.9%, P = 0.04）. There were comparable rates of cerebrovascular （0.3 vs. 0.3%） or nonvascular complications （1.8 vs. 1.2%）. Good arrhyth-mia control was inferior in elderly patients as compared with the rest of the cohort, both without and with antiarrhythmic drugs： 44.2% vs.58.2% （P 〈 0.0001） and 78.2 vs. 83.2% （P 〈 0.01）, respectively. Poor arrhythmia control was associated with relative risk of all-cause mor-tality of 2.7 （95% CI： 1.1-6.4） in elderly patients and 1.4 （95% CI： 0.9-2.0） in younger subjects. Conclusions Catheter ablation for AF inelderly patients is safe although somewhat less effective. Good arrhythmia control is associated with better survival, especially in elderly patients.

Mechanisms and clinical significance of early recurrences of atrial arrhythmias after catheter ablation for atrial fibrillation

Early recurrence of atrial arrhythmias(ERAA) after ablation is common and strongly predicts late recurrences and ablation failure. However, since arrhythmia may eventually resolve in up to half of patients with ERAA, guidelines do not recommend immediate reintervention for ERAA episodes occurring during a 3-mo postablation blanking period. Certain clinical demographic, electrophysiologic, procedural, and ERAA-related characteristics may predict a higher likelihood of longterm ablation failure. In this review, we aim to discuss potential mechanisms of ERAA, and to summarize the clinical significance, prognostic implications, and treatment options for ERAA.

Clinical outcomes of radiofrequency catheter ablation of atrial fibrillation in octogenarians lO-year experience of a one high-volume center

Background Prevalence of atrial fibrillation （AF） increases with age. Radiofrequency catheter ablation （RFCA） is an establishedtreatment option superior to antiarrhythmics （AAs）. In this study, we investigated safety and efficacy of RFCA of AF in octogenarians.Methods From our database, we extracted procedural and follow-up data for patients 〉 80 years with symptomatic AF undergoing RFCAand compared this population to RFCA patients 〈 50 years. All patients underwent pulmonary vein isolation （PVI） supplemented by linearlesions in PVI-nonresponders. Arrhythmia-free survival was assessed using seven day Holter every three months post procedure. All patientscompleted their 12 months follow-up. Results Fifty patients aged ≥80 years （80.5 ± 1.6 years） were compared to 259 patients aged 〈 50years （43.5±5.5 years）. The RFCA complication rate did not vary between groups. No differences in procedural characteristics were seenafter being analyzed by type of AF. Among patients with paroxysmal AF, 71.4% octogenarian vs. 84.7% young patients was free of anyarrhythmia, without AAs, after single procedure. For non-paroxysmal AF, arrhythmia-free survival without AAs, was considerably lower（58.6% octogenarians vs. 81.2% younger patients, P = 0.023）. If AAs were used, arrhythmia-free survival for paroxysmal AF increased to90.5% and 92.1% in octogenarians and younger patients, respectively; and in non-paroxysmal AF it increased to 79.3% vs. 88.4%. ConclusionsRFCA is a safe and effective strategy to achieve normal sinus rhythm in a highly selected group of octogenarians. Paroxysmal AF ablation inoctogenarians has similar clinical effectiveness as that seen in much younger patients. Non-paroxysmal AF ablation has lower, but still rea-sonable clinical effectiveness.

Catheter ablation for atrial fibrillation is associated with reduced risk of mortality in the elderly:a prospective cohort study and propensity score analysis

Background It is unclear whether catheter ablation(CA)for atrial fibrillation(AF)affects the long-term prognosis in the elderly.This study aims to evaluate the relationship between CA and long-term outcomes in elderly patients with AF.Methods Patients more than 75 years old with non-valvular AF were prospectively enrolled between August 2011 and December 2017 in the Chinese Atrial Fibrillation Registry Study.Participants who underwent CA at baseline were propensity score matched(1:1)with those who did not receive CA.The outcome events included all-cause mortality,cardiovascular mortality,stroke/transient ischemic attack(TIA),and cardiovascular hospitalization.Results Overall,this cohort included 571 ablated patients and 571 non-ablated patients with similar characteristics on 18 dimensions.During a mean follow-up of 39.75±19.98 months(minimum six months),24 patients died in the ablation group,compared with 60 deaths in the non-ablation group[hazard ratio(HR)=0.49,95%confidence interval(CI):0.30-0.79,P=0.0024].Besides,6 ablated and 29 non-ablated subjects died of cardiovascular disease(HR=0.25,95%CI:0.11-0.61,P=0.0022).A total of 27 ablated and 40 non-ablated patients suffered stroke/TIA(HR=0.79,95%CI:0.48-1.28,P=0.3431).In addition,140 ablated and 194 non-ablated participants suffered cardiovascular hospitalization(HR=0.84,95%CI:0.67-1.04,P=0.1084).Subgroup analyses according to gender,type of AF,time since onset of AF,and anticoagulants exposure in initiation did not show significant heterogeneity.Conclusions In elderly patients with AF,CA may be associated with a lower incidence of all-cause and cardiovascular mortality.

Value of cystatin C in predicting atrial fibrillation recurrence after radiofrequency catheter ablation

Backgroud Recent studies have demonstrated that cystatin C is a valuable risk marker for cardiovascular disease morbidity and mortality.Therefore,we hypothesized that the pre-ablation cystatin C level was associated with post-ablation atrial fibrillation(AF)recurrence.Methods 207 patients were enrolled and completed in this prospective observational study.Patients with AF scheduled for receive radiofrequency catheter ablation(RFCA)therapy were screened for the study.Before ablation therapy,electrocardiogram,24 h holter monitor,transesophageal echocardiography,serum cystatin C,high-sensitivity C-reactive protein,creatinine levels,and routine blood examinations were examined.After ablation,patients were followed up every week for the first month,and then at 2,3,6,9,and 12 months.Thereafter,patients came back to out-patient clinic every six months regularly.Electrocardiogram or 24 h holter monitor were repeated if the patient experienced palpitations or every six months.AF recurrence was defined as atrial flbrillation/atrial flutter or atrial tachycardia lasting≥30 seconds within three months after therapy.Results Compared to patients with no AF recurrence,patients with recurrence had longer AF history(P=0.007),more early recurrence(P=0.000),a larger left atrium(P=0.004),and higher pre-ablation cystatin C levels(P=0.000).Multivariate regression analysis revealed that cystatin C and left atria(LA)diameter were risk factors for AF recurrence.After adjusting for LA diameter,the risk of AF recurrence increased 30%with every milligram cystatin C elevation(95%CI:1.117-1.523).Conclusions Pre-ablation cystatin C levels were associated with AF recurrence after RFCA therapy,an optimal cut-off value of 1.190 mg/L(sensitivity=0.576;specificity=0.851).

Long-term results of single-procedure catheter ablation for atrial fibrillationin pre-and post-menopausal women

Objectives To address whether menopause affects outcome of catheter ablation （CA） for atrial fibrillation （AF） by comparing the safety and long-term outcome of a single-procedure in pre-and post-menopausal women. Methods A total of 743 female patients who underwent a single CA procedure of drug-refractory AF were retrospectively analyzed. The differences in clinical presentation and outcomes of CA for AF between the pre-menopausal women （PreM group, 94 patients, 12.7%） and the post-menopausal women （PostM group, 649 patients, 87.3%） were assessed. Results The patients in the PreM group were younger （P＆lt;0.001） and less likely to have hypertension （P＆lt;0.001） and diabetes （P=0.005） than those in the PostM group. The two groups were similar with regards to the proportion of concomitant mitral valve regurgitation coronary artery disease, left atrium dimensions, and left ventricular ejection fraction. The overall rate of complica-tions related to AF ablation was similar in both groups （P=0.385）. After 43 （16-108） months of follow-up, the success rate of ablation was 54.3%in the PreM group and 54.2%in the PostM group （P=0.842）. The overall freedom from atrial tachyarrhythmia recurrence was simi-lar in both groups. Menopause was not found to be an independent predictive factor of the recurrence of atrial tachyarrhythmia. Conclusions The long-term outcomes of single-procedure CA for AF are similar in pre-and post-menopausal women. Results indicated that CA of AF appears to be as safe and effective in pre-menopausal women as in post-menopausal women.

Catheter ablation of atrial fibrillation in the elderly

Background Atrial fibrillation （AF） catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years （48 males, mean age 68.9 ± 3.0 years old） and 221 patients were〈65 years old （130 males, mean age 52.5 ± 10.4 years old）. After a mean follow-up period of 34.0 ± 15.1 months, 55 （57.9%） patients in the elderly group were free from ar-rhythmia recurrence compared with 149 （67.4%） patients in the younger group （P=0.169）. Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter （P=0.003）, hypertension （P=0.001）, dyslipidemia （P=0.039）, and coronary artery disease （P=0.018） were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.

Catheter ablation of atrial fibrillation: Radiofrequency catheter ablation for redo procedures after cryoablation

AIM: To evaluate the effectiveness of two different strategies using radiofrequency catheter ablation for redo procedures after cryoablation of atrial fibrillation.METHODS: Thirty patients(paroxysmal atrial fibrillation: 22 patients,persistent atrial fibrillation: 8 patients) had to undergo a redo procedure after initially successful circumferential pulmonary vein(PV) isolation with the cryoballoon technique(Arctic Front Balloon,CryoCath Technologies/Medtronic).The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy(CARTO;Biosense Webster) depending on the intra-procedural findings.After discharge,patients were scheduled for repeated visits at the arrhythmia clinic.A 7-day Holter monitoring was performed at 3,12 and 24 mo after the ablation procedure.RESULTS: During the redo procedure,a mean number of 2.9 re-conducting pulmonary veins(SD ± 1.0 PVs) were detected(using a circular mapping catheter).In 20 patients,a segmental approach was sufficient to eliminate the residual pulmonary vein conduction because there were only a few recovered pulmonary vein fibres.In the remaining 10 patients,a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction.All recovered pulmonary veins could be isolated successfully again.At 2-year follow-up,73.3% of all patients were free from an arrhythmia recurrence(22/30).There were no major complications.CONCLUSION: In patients with an initial circumferential pulmonary vein isolation using the cryoballoon technique,a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation.

Catheter ablation of atrial fibrillation facilitated by preprocedural three-dimensional transesophageal echocardiography: Long-term outcome

AIM To evaluate the long-term outcome of catheter ablation of atrial fibrillation(AF) facilitated by preprocedural threedimensional(3-D) transesophageal echocardiography.METHODS In 50 patients, 3D transesophageal echocardiography(3D TEE) was performed immediately prior to an ablation procedure(paroxysmal AF: 30 patients, persistent AF: 20 patients). The images were available throughout the ablation procedure. Two different ablation strategies were used. In most of the patients with paroxysmal AF, the cryoablation technique was used(Arctic Front Balloon, Cryo Cath Technologies/Medtronic; group A2). In the other patients, a circumferential pulmonary vein ablation was performed using the CARTO system [Biosense Webster; group A1(paroxysmal AF), group B(persistent AF)]. Success rates and complication rates were analysed at 4-year follow-up.RESULTS A 3D TEE could be performed successfully in all patients prior to the ablation procedure and all four pulmonaryvein ostia could be evaluated in 84% of patients. The image quality was excellent in the majority of patients and several variations of the pulmonary vein anatomy could be visualized precisely(e.g., common pulmonary vein ostia, accessory pulmonary veins, varying diameter of the left atrial appendage and its distance to the left superior pulmonary vein). All ablation procedures could be performed as planned and almost all pulmonary veins could be isolated successfully. At 48-mo followup, 68.0% of all patients were free from an arrhythmia recurrence(group A1: 72.7%, group A2: 73.7%, group B: 60.0%). There were no major complications.CONCLUSION3 D TEE provides an excellent overview over the left atrial anatomy prior to AF ablation procedures and these procedures are associated with a favourable long-term outcome.

Modified Maze lines plus pulmonary vein isolation created by radiofrequency catheter ablation on the atrial wall to treat atrial fibrillation in elderly

Objective To evaluate the effect of modified Maze lines plus pulmonary vein (PV) isolation created by radiofrequency catheter ablation (RFCA) on atrial wall guided by a novel geometry mapping system in the treatment of elderly patients with paroxysmal atrial fibrillation (PAF). Methods After regular electrophysiological study, transseptal punctures were achieved twice with Swartz L1 and R1 sheaths. PV angiographies were conducted to evaluate their orifices and branches. A balloon electrode array catheter with 64 electrodes was put in the middle of the left atrium. Atrium geometry was constructed using Ensite 3000 Navx system. Two RFCA lesion loops and three lines (modified Maze) were created on left and right atrial walls. Each lesion point was ablated for 30 seconds with preset temperature 50 (ae) and energy 30W. The disappearance or 80% decrease of the amplitude of target atrial potential and 10 to 20(|), decrease of ablation impedance were used as an index of effective ablation. Results A total of 11 patients (7 male and 4 female, mean age, 68.7±5.1 years) were enrolled. PAF history was 7.9±4.5 years. PAF could not be prevented by mean 3.1±1.6 antiarrhythmic agents in 6.3±3.4 years. None of the patients had complications with structural heart disease or stroke. Left atrial diameter was 41.3±3.6 mm and LVEF was 59.2±3.7% on echocardiography. Two loops and three lines were completed with 67.8±13.1 (73-167) lesion points. Altogether 76-168 (89.4±15.3) lesion points were created in each patient. PAF could not be provoked by rapid burst pacing up to 600 beat per minute delivered from paroxysmal coronary sinus electrode pair.Complete PV electrical isolation was confirmed by three-dimensional activation mapping. Mean procedure time was 2.7±0.6 hours and fluoroscopy time was 17.8±9.4 minutes. Patients were discharged with oral aspirin and without antiarrhythmic agents. During follow up of 6.5±1.8 months, seven patients were PAF symptom free (63.6%). PAF attacks were decreased more than 70% in two patients (18.2%). PAF frequency did not change in another two patients (18.2%). Conclusions Ensite 3000 Navx guided modified Maze lines plus PV isolation on the atrial wall is safe and feasible in the elderly patients. It has the advantages of exact procedural endpoint, shorter X-ray exposure, fewer complications and satisfied long-term effect PAF control.

Impact of computed tomography image and contact force technology on catheter ablation for atrial fibrillation

AIM:To investigate the impact of using computed tomography(CT) and contact force(CF) technology on recurrence of atrial tachyarrhythmia after atrial fibrillation(AF) ablation.METHODS: This non-randomized study included 2 groups of patients. All patients had symptomatic recurrent paroxysmal or persistent AF and were treated with at least 1 anti arrhythmic medication or intolerant to medication. The first group included 33 patients who underwent circumferential pulmonary veins isolation(PVI) for AF during 2012 and 2013 guided by CT image integration(Cartomerge, Biosense Webster, Diamond Bar, CA, United States) of left atrium and pulmonary veins into an electroanatomic mapping(EAM) system(CT group) using standard irrigated radiofrequency catheter(Thermo Cool, Carto, Biosense Webster, Diamond Bar, CA, United States) or irrigated catheter with integrated CF sensor(Smart Touch, Carto, Biosense Webster, Diamond Bar, CA, United States). The second group included immediately preceding 32 patients who had circumferential PVI by standard irrigated catheter(Thermo Cool) using only EAM(Carto) system(EAM group). Linear lesions were performed according to the discretion of operator. RESULTS: Sex, age, and persistent AF were not different between groups. PVI was achieved in all patients in both groups. Linear ablations including cavo-tricuspid isthmus and or roof line ablation were not different between groups. Free of atrial tachyarrhythmia during follow-up of 24 mo was significantly higher among CT group compared to EAM group(81% vs 55%; respectively; P = 0.027). When 11 patients from CT group who had ablation using Smart Touch catheter were excluded, the difference between CT group and EAM became non significant(73% vs 55%; respectively; P = 0.16). Sub analysis of CT group showed that patients who had ablation using Smart Touch catheter tend to be more free of atrial tachyarrhythmia compared to patients who had ablation using standard irrigated catheter during follow-up(100% vs 73%; respectively; P = 0.07). Major complications(pericardial effusion, cerebrovascular accident/transient ischemic attack, vascular access injury requiring intervention) did not occurred in both groups.CONCLUSION:These preliminary results suggest that CT image integration and CF technology may reduce the recurrence of atrial tachyarrhythmia after catheter ablation for AF.

Catheter ablation of persistent atrial fibrillation:The importance of substrate modification

Accumulating data have shown that elimination of atrial fibrillation(AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms(CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency(DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively "healthy islands" within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes.

The trend of change in catheter ablation versus antiarrhythmic drugs for the management of atrial fibrillation over time： a meta-analysis and meta-regression

Objective To evaluate the trend of change in the efficacy and safety of catheter ablation compared with antiarrhythmic drug therapy （ADT） for rhythm control in patients with atrial fibrillation （AF） over time. Methods The online databases PubMed and EMBASE were searched for relevant studies. STATA software （version 12.0） was used to perform the meta-analysis and meta-regression. Results Fifteen randomized controlled trials including 2249 patients with AF were identified. The pooled results showed that catheter ablation was associated with a 52% reduction in the risk of AF recurrence compared with ADT [risk ratio （RR） = 0.48, 95% confidence interval （CI）： 0.40-0.57, I2 = 70.7%）. Subgroup analyses showed that catheter ablation exhibited less efficacy in studies after 2011 compared to studies before 2011 （RR = 0.61, 95% CI： 0.54-0.68, I2 = 9.3% and RR = 0.34, 95% CI： 0.24-0.47, I2 = 69.9%, respectively）, and the safety outcome showed a 1.08-fold higher incidence of adverse events （14.2% vs. 7.3%; RR = 1.08, 95% CI： 1.04-1.13） in studies after 2011. Conclusions Catheter ablation appears to be superior to ADT for rhythm control. However, less efficacy and a higher rate of adverse events were observed in studies after 2011 compared to studies before 2011.

Clinical utility of left atrial strain in predicting atrial fibrillation recurrence after catheter ablation: An up-to-date review

Rhythm control is the core part of the integrated management of atrial fibrillation(AF),especially in the early stages.Despite advances in catheter ablation(CA),the recurrence rate of AF after CA remains high.As a result,stratification and early management of AF recurrence after CA are critical.Currently,predictors of recurrence of AF after CA are mostly based on dysfunction caused by structural remodeling,apart from traditional risk factors.Atrial strain is a recently developed important parameter for detecting the deformability of atrial myocardium during the cardiac cycle prior to atrial remodeling.Although there is only preliminary evidence,atrial strain is still a promising parameter in predicting the recurrence of AF after CA at an early stage.This review focuses on the evaluation of atrial strain,the current applications of atrial strain in assessing atrial function,and predicting the recurrence of AF after CA.We summarize the contents related as follows:(1)CA for rhythm control in AF;(2)Evaluation methods of atrial strain;(3)Atrial strain in the remodeling and reverse remodeling of AF;and(4)Clinical applications of atrial strain in predicting the recurrence of AF after CA.Although there is accumulating evidence on the role of decreased atrial strain in the early prediction of AF recurrence,atrial strain is limited in clinical practice for lacking exact cut-off values and difficulty in distinguishing specific function phases of the atrium.More research is needed in the future to add strength to the early prediction value of atrial strain in AF recurrences.

Catheter ablation for atrial fibrillation in a subset of patients with concomitant hypertension

AIM:To study patients with atrial fibrillation and hypertension who had successful catheter ablation for changes in blood pressure 1 year later.METHODS:A retrospective study was performed on patients who had catheter ablation for atrial fibrillation(AF) and hypertension(HTN) which included local autonomic ganglionated plexi denervation and pulmonary veins isolation.Of the records of 119 patients,followup data was found in order to determine the presence of sinus rhythm and data on systolic(SBP) and diastolic blood pressure at 2 wk,3 mo,6 mo and 1 year after the ablation procedure.Transthoracic echocardiograms were taken at the time of the catheter procedure to determine left atrial dimensions(LADs) and left ventricular size.RESULTS:There was no significant difference in the preablation mean blood pressures between the two groups(P = 0.08).After 1 year 33 of the 60 with AF and HTN were in sinus rhythm,of whom 12 had normal LADs,≤ 4 cm Group 1,and 21 had enlarged left atria(LADs > 4 cm,Group 2).For Group 1,at 1 year of follow up,there was a significant difference in the SBP(119.2 ± 13 mm Hg) compared to pre-ablation(142.6 ± 13.7 mm Hg,P = 0.001).For Group 2,there was no significant difference in the SBP,pre-ablation(130.3 ± 17.5 mm Hg) and at 1 year of follow up(130.4 ± 13.4 mm Hg,P = 0.75).All patients were on similar anti-hypertensive medications.There was a trend for a greater left ventricular size in Group 2 compared to Group 1.CONCLUSION:We suggest that Group 1 had HTN due to sympathetic hyperactivity,neurogenic HTN;whereas HTN in Group 2 was based on arterial vasoconstriction.

Percutaneous transhepatic access for catheter ablation of a patient with heterotaxy syndrome complicated with atrial fibrillation:A case report

BACKGROUND Atrial fibrillation(AF)is one of the most common arrhythmias,and radiofrequency catheter ablation is the most effective treatment strategy.The inferior vena cava(IVC)is a common approach for radiofrequency ablation of AF.However,this approach may not be applied to some cases such as chronic venous occlusions,surgical ligation of the IVC,and heterotaxy syndrome(HS).CASE SUMMARY A 68-year-old man with HS suffered from severely symptomatic persistent AF for 9 years,and we successfully ablated by percutaneous transhepatic access.CONCLUSION In patients without femoral vein access,the use of the hepatic vein for pulmonary vein isolation is a viable alternative for invasive electrophysiology procedures.

Catheter ablation for atrial fibrillation in heart failure:untying the Gordian knot

Atrial fibrillation(AF) and heart failure(HF) are complex clinical entities that occur concomitantly in a significant population of patients, and their prevalence is rising in epidemic proportions. Traditionally, both rate and rhythm control strategies have been regarded as equivalent in the management of dysrhythmia in this AF-HF cohort with escalation of treatment largely guided by symptoms. Both disorders are involved in an elaborate pathophysiological interplay with shared cardiovascular risk factors that contribute to the development and sustenance of both AF and HF. Recent studies and continued development of evidence to support catheter ablation for AF has brought into question the traditional belief in equivalence between rate and rhythm control. Indeed, recent trials, in particular the CASTLE-AF(Catheter Ablation versus Standard Conventional Therapy in Patients with Left Ventricular Dysfunction and Atrial Fibrillation) study, suggest that catheter ablation for AF improves survival and rates of hospitalisation in patients with concomitant HF and AF, threatening a paradigm shift in the management of this patient cohort. The evident mortality benefit from clinical trials suggests that catheter ablation for AF should be considered as a therapeutic intervention in all suitable patients with the AF-HF syndrome as these patients may derive the greatest benefit from restoration of sinus rhythm. Further research is needed to refine the evidence base, especially to determine which subgroup of HF patients benefit most from catheter ablation and what is the optimal timing.

Reduction of radiation exposure in catheter ablation of atrial fibrillation: Lesson learned

Over the last decades, the concern for the radiation injury hazard to the patients and the professional staff has increased in the medical community. Since there is no magnitude of radiation exposure that is known to be completely safe, the use of ionizing radiation during medical diagnostic or interventional procedures should be as low as reasonably achievable(ALARA principle). Nevertheless, in cardiovascular medicine, radiation exposure for coronary percutaneous interventions or catheter ablation of cardiac arrhythmias may be high: for ablation of a complex arrhythmia, such as atrial fibrillation, the mean dose can be > 15 m Sv and in some cases > 50 m Sv. In interventional electrophysiology, although fluoroscopy has been widely used since the beginning to navigate catheters in the heart and the vessels and to monitor their position, the procedure is not based on fluoroscopic imaging. Therefore, nonfluoroscopic three-dimensional systems can be used to navigate electrophysiology catheters in the heart with no or minimal use of fluoroscopy. Although zerofluoroscopy procedures are feasible in limited series, there may be difficulties in using no fluoroscopy on a routine basis. Currently, a significant reduction in radiation exposure towards near zero-fluoroscopy procedures seems a simpler task to achieve, especially in ablation of complex arrhythmias, such as atrial fibrillation. The data reported in the literature suggest the following three considerations. First, the use of the non-fluoroscopic systems is associated with a consistent reduction in radiation exposure in multiple centers: the more sophisticated and reliable this technology is, the higher the reduction in radiation exposure. Second, the use of these systems does not automatically lead to reduction of radiation exposure, but an optimized workflow should be developed and adopted for a safe non-fluoroscopic navigation of catheters. Third, at any level of expertise, there is a specific learning curve for the operators in the non-fluoroscopic manipulation of catheters; however, the learning curve is shorter for more experienced operators compared to less experienced operators.

Visualization of catheter ablation for atrial fibrillation:Impact of devices and anatomy

Endocardial access to the left atrium is commonly achieved to treat patients with atrial fibrillation, using different device delivery systems for cardiac ablation. But the large variation in human anatomy presses the limits of existing medical devices. In this unique study, we directly visualized the device-tissue interface in fresh reanimated human hearts using Visible Heart® methodologies. Our goal was to better understand any opportunities to improve therapeutic approaches. The visual images obtained in this study(also featured in this article) allow a more intimate grasp of the key steps required in various ablation procedures, as well as some limitations of current device designs. These images show the potential risks of conducting transseptal punctures and the difficulties of placing catheter tips in certain scenarios(e.g., when creating circumferential lesions); they also demonstrate potential problems that could occur while attempting to place catheter tips on such anatomies like the mitral isthmus. In our analysis of these images, we focus on where enhancements are needed to refine device functionality.