Procedural and Intermediate-term Results of the Electroanatomical-guided Cardioneuroablation for the Treatment of Supra-Hisian Second- or Advanced-degree Atrioventricular Block: the PIRECNA multicentre registry.

AIMS: Prior case series showed promising results for cardioneuroablation in patients with vagally induced atrioventricular blocks (VAVBs). We aimed to examine the acute procedural characteristics and intermediate-term outcomes of electroanatomical-guided cardioneuroablation (EACNA) in patients with VAVB. METHODS AND RESULTS: This international multicentre retrospective registry included data collected from 20 centres. Patients presenting with symptomatic paroxysmal or persistent VAVB were included in the study. All patients underwent EACNA. Procedural success was defined by the acute reversal of atrioventricular blocks (AVBs) and complete abolition of atropine response. The primary outcome was occurrence of syncope and daytime second- or advanced-degree AVB on serial prolonged electrocardiogram monitoring during follow-up. A total of 130 patients underwent EACNA. Acute procedural success was achieved in 96.2% of the cases. During a median follow-up of 300 days (150, 496), the primary outcome occurred in 17/125 (14%) cases with acute procedural success (recurrence of AVB in 9 and new syncope in 8 cases). Operator experience and use of extracardiac vagal stimulation were similar for patients with and without primary outcomes. A history of atrial fibrillation, hypertension, and coronary artery disease was associated with a higher primary outcome occurrence. Only four patients with primary outcome required pacemaker placement during follow-up. CONCLUSION: This is the largest multicentre study demonstrating the feasibility of EACNA with encouraging intermediate-term outcomes in selected patients with VAVB. Studies investigating the effect on burden of daytime symptoms caused by the AVB are required to confirm these findings.

Junctional rhythm during cryoablation for typical atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Cryoablation is being used as an alternative to radiofrequency (RF) ablation for atrioventricular nodal reentrant tachycardia (AVNRT) owing to the lower risk of atrioventricular block (AVB) compared to RF ablation. Junctional rhythm often occurs during successful application of RF ablation for AVNRT. In contrast, junctional rhythm has rarely been reported to occur during cryoablation. This retrospective study evaluated the characteristics of junctional rhythm during cryoablation for typical AVNRT. METHODS AND RESULTS: This retrospective study included 127 patients in whom successful cryoablation of typical AVNRT was performed. Patients diagnosed with atypical AVNRT were excluded. Junctional rhythm appeared during cryofreezing in 22 patients (17.3%). These junctional rhythms appeared due to cryofreezing at the successful site in the early phase within 15 s of commencement of cooling. Transient complete AVB was observed in 10 of 127 patients (7.9%), and it was noted that atrioventricular conduction improved immediately after cooling was stopped in these 10 patients. No junctional rhythm was observed before the appearance of AVB. No recurrence of tachycardia was confirmed in patients in whom junctional rhythm occurred by cryofreezing at the successful site. CONCLUSION: Occurrence of junctional rhythms during cryoablation is not so rare and can be considered a criterion for successful cryofreezing. Furthermore, junctional rhythm may be associated with low risk of recurrent tachycardia.

Atrioventricular conduction recovery immediately after the re-operation in a repaired CHD patient.

This is a case of a 2.7-year-old girl with trisomy 21 and double outlet right ventricle who underwent epicardial pacemaker system placement for a surgical atrioventricular block and achieved atrioventricular conduction recovery immediately after residual ventricular septal defect closure. Although ventricular pacing ratio was 100% before re-operation, it declined to approximately 25% on the 6th post-operative day and was <1% 3 years after re-operation.

Cardioneuroablation for vasovagal syncope and atrioventricular block: A step-by-step guide.

Catheter-based cardioneuroablation is increasingly being utilized to improve outcomes in patients with vasovagal syncope and atrioventricular block due to vagal hyperactivity. There is now increasing convergence among enthusiasts on its various aspects, including patient selection, technical steps, and procedural end-points. This pragmatic review aims to take the reader through a step-by-step approach to cardioneuroablation: we begin with a brief overview of the anatomy of intrinsic cardiac autonomic nervous system, before focusing on the indications, preprocedure and postprocedure management, necessary equipment, and its potential limitations.

Treatment of atrial tachycardia arising after superior transseptal approach mitral valve surgery: Insights from ultra-high-density mapping to prevent atrioventricular block.

INTRODUCTION: Mitral valve surgery employing a superior transseptal approach (STA) is associated with arrhythmogenicity and intra-atrial conduction delay, despite being optimal for visualization of the surgical field. It is sometimes difficult to treat atrial tachycardias (AT) that arise after STA. To investigate AT circuits that arise after STA in detail in order to identify the optimal ablation line, using ultra-high-resolution mapping (UHRM). METHODS: We retrospectively analyzed 12 AT from 10 patients (median age 70 years, nine males) who had undergone STA surgery. The tachycardias were mapped using the Rhythmia mapping system (Boston Scientific, Natick, Massachusetts). RESULTS: The 12 STA-related AT (STA-AT) circuits were classifiable as follows according to location of the optimal ablation line: (1) peri-septal incision STA-AT (n = 3), (2) cavotricuspid isthmus (CTI) dependent STA-AT (n = 7), and (3) biatrial tachycardia (n = 2). Radiofrequency (RF) application terminated 11 of the 12 STA-AT. We found that difference in STA-AT circuit type was due to characteristics of the septal incision line made for STA. UHRM was important in identifying optimal ablation sites that did not create additional conduction disturbances in the right atrium (RA). CONCLUSIONS: ATs after STA involve complex arrhythmia circuits due to multiple and long incision lines in the RA. Accurate understanding of the arrhythmia circuit and sinus conduction in the RA after STA is recommended for treating post-surgical tachycardia in a minimally invasive manner.

Long-term outcomes of arrhythmia and distinct electrophysiological features in congenitally corrected transposition of the great arteries in an Asian cohort.

Congenitally corrected transposition of the great arteries (ccTGA) is associated with various types of arrhythmia, including supraventricular tachycardia (SVT) and complete atrioventricular block (cAVB). Our study aims to characterize the arrhythmia burden, associated risk factors, arrhythmia mechanisms, and the long-term follow-up results in patients with ccTGA in a large Asian cohort. METHODS: We enrolled 104 patients (43 women and 61 men) diagnosed with ccTGA at our institution. The mean age at last follow-up was 20.8 years. RESULTS: For 40 patients (38%) with tachyarrhythmia, paroxysmal SVT (PSVT) and atrial arrhythmia were observed in 17 (16%) and 27 (26%) patients, respectively, with 4 patients (4%) having both types of SVT. The 20-year and 30-year SVT-free survival rates were 68% and 54%, respectively. Seven patients (7%) developed cAVB: 2 (2%) developed spontaneously, and the other 5 (5%) was surgically complicated (surgical risk of cAVB: 7%, all associated with ventricular septal defect repair surgery). PSVT was mostly associated with accessory pathways (5/9) but also related to twin atrioventricular nodal reentry tachycardia (3/9) and atrioventricular nodal reentry tachycardia (1/9). Most of the accessory pathways were located at tricuspid valve (9/10). Catheter ablation successfully eliminated all PSVT substrates (10/10) and most of the atrial arrhythmia substrates (3/5), with low recurrence rate. CONCLUSIONS: The arrhythmia burden in patients with ccTGA is high and increases over time. However, cAVB incidence was relatively low and kept stationary in this Asian cohort. The mechanisms of SVT are complicated and can be controlled through catheter ablation.

Cryofreezing for slow-pathway modification in patients with slow-fast AVNRT: Efficacy, safety, and electroanatomical relation between sites of transient AV block and sites of successful cryoablation.

INTRODUCTION: Cryoablation has emerged as an alternative to radiofrequency ablation for treating atrioventricular nodal reentrant tachycardia (AVNRT). The aim of this prospective study was to evaluate the efficacy and safety of cryoapplication at sites within the mid/high septal region of Koch's triangle and the relation between sites of transient AV block (AVB) and sites of successful cryoablation. METHODS AND RESULTS: Included were 45 consecutive patients undergoing slow-fast AVNRT cryoablation. Initial delivery of cryoenergy was to the mid-septal to high septal region of Koch's triangle. Transient AVB occurred during cryoenergy delivery in 62% (28/45) of patients. Median distance between sites at which cryofreezing successfully eliminated slow pathway conduction and sites of AVB was 4.0 (3.25-5.0) mm. Sites of successful cryoablation tended to be to the left and inferior to the AVB sites. The atrial/ventricular electrogram ratio was significantly lower at sites of successful cryoablation than at AVB sites (0.25 [0.17-0.56] vs. 0.80 [0.36-1.25], p < .001). Delayed discrete or fractionated atrial electrograms were recorded more frequently at sites of successful cryoablation than at AVB sites (78% vs. 20%, p < .001). No persistent AV conduction disturbance occurred, and 96% (43/45) of patients showed absence of recurrence at a median follow-up time of 25.0 months. CONCLUSION: Cryoablation of slow-fast AVNRT and targeting the mid/high septal region of Koch's triangle was highly successful. AVB frequently emerged near the site at which the slow pathway was eliminated but always resolved by regulating the energy delivery under careful monitoring, and it may be distinguishable by its local electrogram features.

Atrioventricular Block after Tricuspid Valve Surgery.

Tricuspid valve (TV) surgery is associated with a high risk of postoperative pacemaker requirement. We set out to identify the incidence of atrioventricular block (AVB) after TV surgery and determine whether atrioventricular conduction recovers within time.We investigated pre/intra- and postoperative predictors of AVB in patients who underwent tricuspid valve surgery (not only isolated TV surgery) at our institution between 2004 and 2017. Patients who had pacemakers prior to surgery were excluded.One year after surgery, 5.8% of the surviving cohort had received a pacemaker due to AVB. In the complete follow-up time, 33 out of 505 patients required pacemaker implantation because of AVB. Of the 37 patients who presented to the intensive care unit postoperatively with AVB III, 14 (38%) underwent pacemaker implantation for AVB, and 20 (54%) did not require a pacemaker. AVB III at ICU admission was identified as a predictor of pacemaker implantation (OR: 9.7, CI: 3.8-24.5, P < 0.001). TV endocarditis was also identified as a predictor (OR: 12.4, CI: 3.3-46.3, P < 0.001). Eleven out of 32 patients (34%) with tricuspid endocarditis required a pacemaker for AVB. The mean ventricular pacing burden within the first 5 years after pacemaker implantation was 79%.The issue of AVB after TV surgery is significant. Both the initial rhythm after surgery and etiology of the tricuspid disease can help predict pacemaker requirement. Within the first 5 years after surgery, the ventricular pacing burden remains high without relevant rhythm recovery.

Network meta-analysis of His bundle, biventricular, or right ventricular pacing as a primary strategy for advanced atrioventricular conduction disease with normal or mildly reduced ejection fraction.

INTRODUCTION: Although right ventricular pacing (RVP) may impair ventricular function, it is commonly used for advanced atrioventricular block (AVB) and normal or mildly reduced ejection fraction (EF). We aimed to compare His bundle pacing (HBP), biventricular pacing (BiVP), and RVP for advanced AVB in patients with normal or mildly reduced EF. METHODS AND RESULTS: MEDLINE, Embase, Cochrane CENTRAL, ClinicalTrials.gov, Scopus, and Web of Science were searched. Outcomes were all-cause death, heart failure hospitalizations (HFH), EF, left ventricular volumes, 6-minute walk test, and QRS duration. HBP or BiVP was compared with RVP. Subsequently, network meta-analysis compared the three pacing options. Our protocol was registered in PROSPERO (CRD42018094132). Six studies compared BiVP and RVP (704 vs 614 patients) and four compared HBP and RVP (463 vs 568 patients). Follow-up was 6 months to 5 years. There was significantly lower mortality and HFH with HBP or BiVP as compared with RVP (odds ratio [OR], 0.66, [0.51-0.85], P = .002; OR, 0.61 [0.45-0.82], P < .001, respectively]. HBP or BiVP also showed significant increase in EF and decrease in QRS duration (mean difference [MD], 5.27 [3.86-6.69], P < .001; MD -42.2 [-51.2 to -33.3], P < .001, respectively). In network meta-analysis, HBP and BiVP were associated with significantly improved survival compared to RVP, with surface under the cumulative ranking curve (SUCRA) probability of 79.4%, 69.4%, and 1.2% for HBP, BiVP, and RVP, respectively. For HFH, SUCRA probability was 91.5%, 57.2%, and 1.3%, respectively. CONCLUSION: HBP or BiVP were the superior strategies to reduce all-cause death and HFH for advanced AVB with normal or mildly reduced EF, with no significant difference between BiVP and HBP.

Epicardial Pacemaker in Neonates and Infants: Is There a Relationship Between Patient Size, Device Size, and Wound Complication?

We aimed to investigate the complications after epicardial pacemaker (PM) implantation in neonates and infants and their relationship with factors such as device size and patient size. Between May 2010 and July 2018, 55 patients under 1 year of age who underwent epicardial PM placement were retrospectively evaluated. PM-related complications requiring rehospitalization were determined as wound site problems requiring surgical intervention, battery pocket infection, battery pocket dehiscence without infection, PM removal, relocation of the PM system, and replacement of the PM system with another system. The patients were divided into three groups: < 3 kg, 3-5 kg and > 5 kg. Fifty-five patients underwent PM implantation, 43 (78.2%) because of postoperative atrioventricular block (AVB), 10 (18.2%) because of congenital AVB, and two (3.6%) with diagnoses of c-TGA and AVB. Five (9%) patients incurred 18 complications. No statistically significant difference was observed in complication development between the groups (p > 0.05). Single- or dual-chamber device implantation did not affect complication development (p > 0.05). Despite the role of factors such as low weight, low age, and device volume in the development of wound complications, the relationship between these factors and complications is not statistically significant. Therefore, our results are encouraging in terms of the use of dual-chamber PMs instead of single-chamber ones in heart diseases in which AV synchronization is important.

Surgical Outcomes of Permanent Epicardial Pacing in Neonates and Young Infants Less Than 1 Year of Age.

BACKGROUND: Open surgical implantation of epicardial leads in neonates and infants remains the first option of treatment. We reviewed the long-term outcomes after epicardial pacemaker implantation in neonates and infants. METHODS: From 1989 to 2016, 48 patients (16 neonates) underwent pacemaker implantation within the first year of life. Their median age and weight were 66.5days (range: 0∼319 days), and 4.2kg (range: 1.9∼9.3kg), respectively, at the time of first pacemaker implantation. The indications for pacemaker implantation were postoperative or congenital atrioventricular block, sinus node dysfunction, and/or myocarditis-induced atrioventricular block. Forty-six (46) unipolar epicardial leads (non-steroid-eluting: 22; steroid-eluting: 24) and two bipolar leads (steroid-eluting) were inserted using a median sternotomy or subxiphoid approach. RESULTS: The mean follow-up duration was 8.5±7.9years. The most commonly used generator mode at first implantation was VVI (n=24, 50.0%). Eleven (11) generator mode changes from the initial VVI or VVIR to dual-chamber pacing were made at a mean of 7.0±6.2years after the first implantation for better inter-chamber synchrony and ventricular function. Freedom from reoperation for generator change after the first implantation was 95.3, 70.6, and 21.9% at 1, 5, and 10 years. Eighteen (18) lead malfunction events (34.1%) were detected. Freedom from reoperation for lead change was 97.8, 76.2, and 46.3% at 1, 5, and 10 years. The lead replacement rate was significantly higher in patients with non-steroid-eluting than steroid-eluting leads (p=0.045). CONCLUSIONS: Neonates and infants require more frequent changes in pacemaker generator and leads than the older population. The use of steroid-eluting leads increased lead longevity and reduced the need for surgical re-interventions.

Inadvertent pacemaker lead dislodgement.

Transcatheter aortic valve implantation (TAVI) has become an established treatment option for aortic valve stenosis in patients with a high risk for conventional surgical valve replacement. A well-known complication is the development of conduction abnormalities. In the case of a new third-degree atrioventricular block, the complication can be life-threatening and permanent pacing is needed. Often these patients have a venous sheath placed in the jugular vein for the perioperative period. We report a case of inadvertent dislodgement of a permanent pacemaker lead after removal of a preoperatively placed venous sheath in a TAVI patient.

Marked First-Degree Atrioventricular Block and Pseudo-Pacemaker Syndrome in a Pediatric Patient.

We describe a 17-year-old female who presented with 3 weeks of abdominal pain, exercise intolerance, and an episode of altered mental status found to have marked first-degree atrioventricular block. Exercise stress test and cardiac catheterization demonstrated pseudo-pacemaker syndrome, and a permanent pacemaker was placed. Following placement, she has resolution of symptoms and markedly improved exercise tolerance.

Prophylactic pacemaker placement at first signs of conduction disease in Kearns-Sayre syndrome.

Cardiac conduction disease affects patients with Kearns-Sayre syndrome. We report a young asymptomatic patient with Kearns-Sayre syndrome with abnormal conduction on electrocardiogram and Holter monitor, although not advanced atrioventricular block. She underwent prophylactic pacemaker placement, and rapidly developed complete atrioventricular block, which resulted in 100% ventricular pacing. It may be reasonable to consider prophylactic pacemaker implantation in patients with Kearns-Sayre syndrome with evidence of cardiac conduction disease even without overt atrioventricular block given its unpredictable progression to complete atrioventricular block.

Differential effect of ganglionic plexi ablation in a patient with neurally mediated syncope and intermittent atrioventricular block.

AIMS: In patients with severe neurally mediated syncope (NMS), radiofrequency catheter ablation (RFA) of ganglionic plexi (GP) has been proposed as a new therapeutic approach. Cardio-inhibitory response during NMS is usually related to the sinoatrial (SA) and less frequently to atrioventricular (AV) node. Differential effect of GP ablation on SA and AV node is poorly understood. METHODS AND RESULTS: We report a case of a 35-year-old female with frequent symptomatic episodes of advanced AV block treated by anatomically guided RFA at empirical sites of GPs. After RFA at the septal portion of the right atrium-superior vena cava junction, heart rate accelerated from 62 to 91 beats/min and PR interval prolonged from 213 to 344 ms. Sustained first-degree AV block allowed to observe directly the effects of subsequent RFA on the AV nodal properties. Subsequent RFA at right- and left-sided aspects of the inter-atrial septum had no further effect on heart rate and PR interval. Ablation at the inferior left GP was critical for restoration of normal AV conduction (final PR interval of 187 ms). No bradycardia episodes were observed by implantable loop recorder during the follow-up of 10 months and the patient was symptomatically improved. CONCLUSION: This is the first clinical case showing the differential effect of GP ablation on SA and AV nodal function, and critical importance of targeting the GP at the postero-inferior left atrium. The successful procedure corroborates clinical utility of ablation treatment instead of pacemaker implantation in selected patients with cardio-inhibitory NMS.

Ex utero Intrapartum Treatment to Ventricular Pacing: A Novel Delivery Strategy for Complete Atrioventricular Block with Severe Bradycardia.

Fetuses with anti-SSA-mediated complete atrioventricular block (CAVB) are at high risk for perinatal death if they present at <20 weeks of gestation and develop ventricular rates of <55 beats per minute (bpm), cardiac dysfunction, or hydrops [Izmirly et al.: Circulation 2011;124:1927-1935; Jaeggi et al.: J Am Coll Cardiol 2002;39:130-137; Eliasson et al.: Circulation 2011;124:1919-1926]. After our experience with two such fetuses who died with pulseless electrical activity despite being paced within 30 min of birth, we performed an ex utero intrapartum treatment procedure to ventricular pacing on a 36-week CAVB fetus with cardiac dysfunction, mild hydrops, and a ventricular rate of 46 bpm. While still on placental bypass, temporary epicardial ventricular pacing leads were successfully placed; the infant was delivered and made a successful transition to postnatal life. This approach can improve the 11-fold increase in mortality for the preterm fetus with long-standing CAVB, severe bradycardia, and heart failure.

[Venous thromboembolic complications in patients with cardiovascular implantable electronic devices]. / Venoznye tromboémbolicheskie oslozhneniia u patsientov s serdechno-sosudistymi implantiruemymi élektronnymi ustroistvami.

The problem of venous thromboembolic complications (VTECs) in patients with cardiovascular implantable electronic devices (CIEDs) is extremely important today because of an annually increasing number of surgical interventions for life-threatening arrhythmias and chronic heart failure. There are hitherto no clearly defined reliable risk factors for VTECs due to heterogeneity of the available literature data. Some sources point to elevated thrombus formation in patients with a large number of electrodes, in repeat operative interventions, in the presence of a temporary pacemaker, in implantation on the left side, silicon cover of an electrode, others refute these facts. Still undetermined remains the choice of antithrombotic therapy for prevention and treatment of VTECs in this cohort of patients. Implantation of a VTEC may be accompanied by thrombosis of deep veins of the upper extremities up to the development of total occlusion of veins. In rare cases, thrombosis extends proximally, there appears superior vena cava syndrome which may require surgical treatment. Diagnosis of these diseases is complicated by their symptom-free course in the majority of cases. The most dangerous VTEC is pulmonary thromboembolism very commonly not accompanied by clinical symptomatology or taking its course under the mask of other more frequent diseases. Despite the fact that pulmonary thromboembolism with a source in the system of the superior vena cava is rarely massive, it may lead to the development of chronic postembolic pulmonary hypertension and to decreased quality of life. The article contains a review of the present-day literature and a clinical case report concerning the development of VTECs in a patient with a CIED in the form of thrombosis of the right internal jugular, subclavian and brachiocephalic veins, pulmonary embolism of small branches of the right pulmonary artery, suppuration of the pacemaker's bed and sepsis. Therapy with antibiotics, low-molecular-weight heparins, antiplatelet drugs and anti-inflammatory agents with regular sanitation of the pacemaker's bed turned out effective.

Selective atrial vagal denervation guided by spectral mapping to treat advanced atrioventricular block.

AIMS: Asymptomatic nocturnal long ventricular pauses are usually detected accidentally and it has been suggested that they may lead to sudden death. Identification of predisposing factors could prevent cardiovascular events. METHODS AND RESULTS: We report the case of a patient with frequent asymptomatic nocturnal ventricular pauses of 3-11 s, characteristic of a vagally mediated atrioventricular (AV) block. Echocardiography, treadmill test, thyroid function test levels, and polysomnogram were normal. In an attempt to reduce the risk, it was decided that an atrial vagal denervation induced by radiofrequency (RF) ablation (cardioneuroablation) could be useful. Spectral mapping was used to localize endocardial vagal innervation in the right and left aspects of the inter-atrial septum, responsible for the sinus node and AV node modulation, and RF pulses were applied in those sites only. After finishing the procedure, significant changes were observed in the heart rate (66-90 b.p.m.), atrial-His interval (115-74 ms), Wenckebach cycle length (820-570 ms), and sinus node recovery time (1100-760 ms). Follow-up Holter recording demonstrated that the number of ventricular pauses had reduced from 438 to 0. Heart rate and time domain characteristics were compatible with vagal denervation. CONCLUSION: Ablation of the endocardial vagal innervation sites seems to be safe and efficient in reducing the frequency and the length of the ventricular pauses. It was possible by identifying certain spectral components of the atrial electrogram, resulting in a conservative approach.

High Incidence of Dilated Cardiomyopathy After Right Ventricular Inlet Pacing in Patients With Congenital Complete Atrioventricular Block.

BACKGROUND: Some patients with congenital complete atrioventricular block (CCAVB) develop dilated cardiomyopathy (DCM) after pacemaker implantation (PMI). We evaluated the relationship between pacing site and DCM incidence. METHODS AND RESULTS: We retrospectively evaluated 38 patients with CCAVB; 8 (25%) of 32 patients who had PMI developed DCM/heart failure death (HFD) after PMI, although none of the 6 patients without PMI showed DCM/HFD. All DCM/HFD occurred within 50 months of PMI. Among the 32 patients with PMI, the DCM/HFD incidence was 55% (6/11) for right ventricular inlet (RVI), 18% (2/11) for RV apex (RVA), and 0% for left ventricle (LV) (P=0.013). At the endpoint, the LV ejection fraction and septal-to-posterior wall motion delay of patients with LV pacing were better than those for patients with other pacing sites. Among the 8 DCM/HFD patients, 2 in whom the pacing site was changed from RVI to LV apex or in whom therapy was upgraded to cardiac resynchronization remained alive with no heart failure symptoms, whereas the other 6 died of heart failure. CONCLUSIONS: A total of 25% of the patients who underwent PMI because of CCAVB, but none in the non-PMI group, developed DCM/HFD. DCM/HFD incidence was higher in patients with RVI pacing. Ventricular dyssynchrony related to pacing site may be one cause of DCM in patients with CCAVB. (Circ J 2016; 80: 1251-1258).