Atrioventricular Nodal Reentry Research Articles

Valsalva Aneurysm of Right Sinus: A Case Report and Review of Literature

In this case report, we describe the diagnostic modality of sinus of Valsalva aneurysm (SOVA) in combination with congenital cardiac defect, aortic valve involvement, and conduction abnormality in a 19-year-old patient. Aim of article was to understand the importance of clinicians being cautious about SOVA presenting in young patients, despite cases being rare, and that SOVA requires a thorough SOVA diagnostic approach. We further provide a review of literature highlighting and comparing the treatment options for both unruptured and ruptured SOVAs. The patient presented for examination due to tachycardia and palpitations. A murmur was heard, and the patient was found to have an atrioventricular nodal reentry tachycardia. Echocardiographic evaluation, magnetic resonance imaging, and computed tomography angiography confirmed an aneurysmally dilated aortic root, aortic regurgitation, and ventricular septal defect. Surgical intervention was indicated; however, the patient refused to undergo surgery.

Benefits from catheter ablation in patients with pulmonary hypertension: Recent advances.

Supraventricular tachycardia (SVT) is a frequent complication of pulmonary hypertension (PH). The most prevalent SVTs are atrial fibrillation (AF) and typical atrial flutter (AFL), followed by focal and macroreentrant atrial tachycardia (AT) and nodal arrhythmia (AV nodal reentry tachycardia or AV reentry tachycardia). SVT is frequently associated with functional deterioration and right ventricular failure in PH patients. According to some data, reestablishing sinus rhythm is associated with clinical improvement. Catheter ablation of typical AFL, nodal tachyarrhythmias, or other less complex focal ATs have been shown to be feasible, acutely effective, and safe in patients with PH. However, the long-term clinical outcome is modified by the recurrence of index arrhythmia and the onset of a new SVT. Due to right atrial dilatation, technical issues can arise when ablation is carried out. The role of catheter ablation in patients with AF or more complex AT is even less effective. The results mirror the success rate in the general AF population with non-paroxysmal AF. However, the data is limited, and electrophysiological procedures are also more often complicated by specific adverse events in a severely frail population. Despite these limitations, catheter ablation is the treatment of choice in less complex SVT, but the indications for AF ablation must be more individualized.

Aberrancy masquerading as ventricular tachycardia: Importance of invasive electrophysiology study for diagnosis of wide complex tachycardias

BackgroundDifferentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with aberrancy based on the 12‑lead ECG alone can be imprecise. Implantable cardiac defibrillators (ICD) may be inserted for presumed VT, particularly in patients with syncopal presentation or atypical aberrancy patterns. Accurate diagnosis of these patients facilitated by an electrophysiology study (EPS) may alter diagnosis and management. MethodsWe present a prospective collection of cases across 3 cardiac centers of consecutive patients with WCT presumed to be VT who were referred for consideration of an ICD, and in whom further evaluation including an EPS ultimately demonstrated SVT with aberrancy as the culprit arrhythmia. Results22 patients were identified (17 male, mean age 50±13 years. Available rhythm data at the time of referral was presumptively diagnosed as monomorphic VT in 16 patients and polymorphic VT in 6 patients. Underlying structural heart disease was present in 20 (91%). EPS resulted in a diagnosis of SVT with aberrancy in all cases: comprising AV nodal re-entry tachycardia (n=10), orthodromic reciprocating tachycardia (n=3), focal atrial tachycardia (n=3), AF/AFL (n=3) and 'double fire' tachycardia (n=2). 21 (95%) patients underwent successful ablation. All patients remained free of arrhythmia recurrence at a median of 3.4 years of follow-up. ICD insertion was obviated in 18 (82%) patients, with 1 patient proceeding to ICD extraction. ConclusionSVT with atypical aberrancy may mimic monomorphic or polymorphic VT. Careful examination of all available rhythm data and consideration of an EPS can confirm SVT and obviate the need for ICD therapy.

Feasibility of catheter ablation with zero-fluoroscopy in congenital heart disease

Abstract Background Catheter ablation (CA) with zero and near-zero fluoroscopy has been shown to be safe and effective in patients (pts) without structural heart disease, but there are limited data regarding CA in congenital heart disease (CHD). Aim Our aim was to compare the safety and outcome of zero-fluoroscopy (ZF) and fluoroscopy (non-ZF) CA of CHD pts. Methods This is a single-center retrospective study of CHD pts who underwent CA at our center between 2006-2020. The ZF and non-ZF groups were compared for the complexity of anatomy, arrhythmia substrate, difficulties of vascular access, transseptal or transbaffle puncture, intracardiac pacemaker/ICD, procedural parameters, complications, and acute outcome. Near-ZF CAs (effective dose ≤1 mSv) were assigned to the ZF group. Results The ZF group included 22 pts (age: 22±13 years) and the non-ZF group 48 pts (age: 31±12 years). The distribution of CHD anatomical complexity (mild/moderate/severe) was 18.2%-68.2%-13.6% in the ZF group and 14.6%-68.7%-16.7% in the non-ZF group. Arrhythmia diagnoses were focal atrial tachycardia (ZF: 4.6%), atrial flutter (ZF: 45.4%, non-ZF: 75.0%), atrioventricular reentry tachycardia (AVRT) via manifest accessory pathway (AP) (ZF: 31.8%, non-ZF: 10.4%), AVRT via concealed AP (ZF: 4.6%, non-ZF: 8.3%), and atrioventricular nodal reentry tachycardia (ZF: 13.6%, non-ZF: 6.3%). Difficulties in vascular access occurred in 4.5% of the ZF group and 18.8% of the non-ZF group (p=0.10). The rate of transseptal/transbaffle puncture was significantly higher in the non-ZF group (22.9% vs. 4.6%, p=0.04). In the ZF group 13.6% and in the non-ZF group 20.8% of pts had pacemaker or ICD (p=0.22). Electroanatomical mapping was used in all CAs in both groups. There was no significant difference in procedure time, ablation time and the number of radiofrequency applications (ZF group: 169±53 min, 1205±906 sec, 28±15 vs. non-ZF group: 203±74 min, 1459±940 sec, 34±16, p>0.05). The acute success rate was 100% in both groups. No complications occurred in any group. Conclusion Zero fluoroscopic CA was feasible in 1/3 of the pts with CHD and as safe and effective as fluoroscopic ablation. No significant differences were found in the non-fluroscopy related procedural data between the two groups.

Activation map of koch triangle: a novel approach to AVNRT ablation using CARTO 3 v7

Abstract Background Ablation of slow pathway (SP) is the standard approach for atrioventricular nodal reentry tachycardia (AVNRT) treatment (1). Low-voltage bridge is an optimal target during mapping using low x-ray exposure (2,3). Purpose We want to assess a new tool to identify SP by activation mapping of Koch’s triangle using CARTO PRIME V7 Methods Triangle of Koch 3D-activation map were obtained from intracardiac contact mapping during low x-ray CARTO 3 procedures (Figure 1). In 60 patients (39 % males, mean age 60.3 ± 14.7 years) undergoing ablation for AVNRT, an automatic activation map using a DECANAV mapping catheter and CARTO Confidense, Coherent, and FAM DX software modules were obtained. Results We indentified SP in all patients as the latest atrioventricular node activation area; RF catheter ablation (RFCA) elicited junctional beats. The mean dose-area product (DAP) was 16.5 ± 2.7 cGy/cm2, the mean fluoroscopy time exposure was 2.9 ± 2 min, the mean ablation index was 428.6 ± 96.6, and the mean contact force was 8 ± 2.8 g. There were no adverse event during the procedure and no AVNRT recurrences during a mean follow-up of 14.3 ± 8.3 months. Conclusions Ablation of the SP by automatic mapping using Confidense, Coherent, and FAM DX software modules is a new approach to AVNRT ablation. The CARTO3 V7 system defines a 3D map of the latest AV node activation area during sinus rhythm allowing a highly effective RFCA under low fluoroscopy time exposure without recurrences or AV blocks.Figure 1

Comparative study of lesions obtained with radiofrequency between irrigated ablation catheter with flexible tip and non-irrigated catheter in ex vivo porcine heart slices

Abstract Background Lesion formation through radiofrequency (RF) is related to various parameters, including power, contact force, duration of energy delivery and temperature. Notably, the characteristics of the lesions differ when comparing irrigated to non-irrigated catheters. Non-irrigated catheter lesions present a larger surface area and shallower depth, while irrigated catheters induce deeper lesions with higher volumes. Particularly, flexible-tip open-irrigated catheter exhibit unique irrigation characteristics and the resulting lesions may show a reduced surface area but extend deeper into the tissue. Main drawbacks of using non-irrigated catheter are the risk of clot formation and of steam pops, both possibly avoidable with an irrigated catheter. Purpose The aim of the study was to demonstrate that flexible-tip open-irrigated catheter generate lesions with a smaller surface area and deeper extension when compared to non-irrigated catheter. Methods An ex vivo model consisting of porcine heart slices in a warmed saline chamber was used. A flexible-tip open-irrigated ablation catheter and a non-irrigated catheter were positioned with a stable tissue contact weight ranging from 10 to 20 g of force in perpendicular position. RF was delivered at powers of 20, 30 and 40 Watt for 60s. Lesion dimensions were analyzed. The occurrence of steam pop was registered. Results The ablations were conducted using flexible-tip open-irrigated (n=55) and non-irrigated (n=39) catheters in a power-control mode. Superficial length and width of lesions were greater with the non-irrigated catheter than with the irrigated catheter, irrespective of the power delivered (superficial length: p=0,0001 at 20W, p=0,002 at 30 W and p=0,0001 at 40 W; superficial width: p=0,001 at 20 W, p=0,019 at 30 W and p=0,003 at 40 W). When computing superficial areas, lesions performed with the non-irrigated catheter were significantly wider, regardless of the power delivered (p=0,001 at 20 W, p=0,005 at 30 W and p=0,001 at 40 W). The irrigated catheter determined significantly greater values of lesion maximum depth at high power delivery (40 W, p=0.007). No steam pop was observed using the irrigated ablation catheter, while 12 steam pops occurred with the non-irrigated catheter. Conclusions This study highlights that RF ablation using flexible-tip open-irrigated catheter has the potential to generate smaller lesion areas when compared to a non-irrigated tip. Furthermore, it may contribute to decrease steam pops, even with escalating power output. This irrigated catheter might be a preferable choice when precision is crucial, particularly in determining superficial area of lesions. Specifically, it might be advantageous for procedure as atrioventricular nodal reentry tachycardia (AVNRT) ablation, minimizing the risk of iatrogenic conduction disturbance related to RF delivery in the region of the compact AV node, located superficially at a millimeter distance from the ablation site.Experiment setting, lesion measurementsLesion superficial area

Voltage and propagation mapping: New tools to improve successful ablation of atrioventricular nodal reentry tachycardia.

Mapping system is useful in ablation of atrioventricular nodal reentry tachycardia (AVNRT) and localization of anatomic variances. Voltage mapping identifies a low voltage area in the Koch trianglecalled low-voltage-bridge (LVB); propagation mapping identifies the collision point (CP) of atrial wavefront convergence. We conducted a prospective study to evaluate the relationship between LVB and CP with successful site of ablation and identify standard value for LVB. Three-dimensional (3D) maps of the right atria were constructed from intracardiac recordings using the ablation catheter. Cut-off values on voltage map were adjusted until LVB was observed. On propagation map, atrial wavefronts during sinus rhythm collide in the site representing CP, indicating the area of slow pathway conduction. Ablation site was selected targeting LVB and CP site, confirmed by anatomic position on fluoroscopy and atrioventricular ratio. Twenty-seven consecutive patients were included. LVB and CP were present in all patients. Postprocedural evaluation identified standard cut-off of 0.3-1 mV useful for LVB identification. An overlap between LVB and CP was observed in 23 (85%) patients. Procedure success was achieved in all patient with effective site at first application in 22 (81%) patients. There was a significant correlation between LVB, CP, and the site of effective ablation (p = .001). We found correlation between LVB and CP with the site of effective ablation, identifying a voltage range useful for standardized LVB identification. These techniques could be useful to identify ablation site and minimize radiation exposure.

Short history of the DC-Catheter-Ablation

Direct current (DC) catheter ablation in 5patients aiming to interrupt rapid atrioventricular (AV) conduction with atrial fibrillation and subsequent pacemaker implantation was first published by M.M.Scheinman etal. (San Francisco, CA, USA) in 1982. In Germany, L.Seipel, G.Breithardt, and M.Borggrefe reported their first experience with DC catheter ablation in 1984, followed by the group in Bonn (M.Manz and B.Lüderitz) in 1985. The first international DC catheter ablation registry, which also included four German centers, reported DC catheter ablation results of 127 patients in 24centers in 1984. Complete AV block was achieved in 71% patients. In 1992, the Hannover group (H‑J.Trappe, H.Klein and J.Huang) reported results of DC catheter ablation of AV conduction performed between 1983 and 1990 in 100 patients (86% with rapid atrial fibrillation, 14% with AV-node reentry tachycardias). The first successful DC catheter ablation in apatient with Wolff-Parkinson-White (WPW) syndrome was reported in 1985 by F.Morady etal. (San Francisco, CA, USA). In 1987, M.Borggrefe etal. were the first to report aswitch from DC catheter ablation to ahigh-frequency (HF) catheter ablation procedure in apatient with WPW syndrome. The use of DC catheter ablation to treat ventricular tachycardia (VT) was described by G.O.Hartzler (Kansas City, MO, USA) in 3patients in 1983. M.Borggrefe etal. (1989) reported on 24patients who underwent DC catheter ablation for VT. Of those, 17patients did not have VT recurrence within the following 14months. In 1994, the Hannover group (H-JTrappe, H.Klein) published their 5‑year long-term results of DC catheter ablation of VT in 51patients. VT recurrence occurred in 57% patients and overall mortality was also high (16%). Acomparison of DC catheter ablation with HF catheter ablation for recurrent VT was reported in 1994 by G.Gonska etal. (Göttingen, Germany). After 2years follow-up, success rates were not found to be significantly different.

Characteristics of Patients Undergoing Electrophysiologic Procedures in a Tertiary Hospital in Saudi Arabia.

The electrophysiology field has progressed rapidly over the last 2 decades. No study has examined the characteristics of patients and types of electrophysiology procedures performed in the Kingdom of Saudi Arabia. This is important given our distinctly different demographic composition and health system. As such, we sought to describe the characteristics of consecutive patients presenting for electrophysiology procedures in our tertiary care hospital. Data was collected from the electrophysiology database at King Khalid University Hospital for procedures performed between April 2016 and November 2022. Patients' characteristics were retrieved from the electronic medical record. Procedures were categorized into supraventricular tachycardia, premature ventricular contraction and "complex ablations", which included atrial fibrillation and scar-mediated ventricular tachycardia ablation. If no abnormality was found, the procedure was labeled as "normal EP study". Multivariate regression analysis was performed to assess predictors of atrioventricular nodal reentry tachycardia among patients presenting with undifferentiated supraventricular tachycardia. A total of 459 patients were included in the study. The mean age was 42.06 years (±14.89 years), and 256 (55.77 %) were females. The most common procedure was supraventricular tachycardia (n = 289/459, 63.24 %), and only 5 % had complex ablations. The most common type of supraventricular tachycardia ablated was found to be atrioventricular nodal reentry tachycardia (n = 157/289, 54 %). Multivariate logistic regression revealed female sex and age to be independently associated with atrioventricular nodal reentry tachycardia (OR = 2.27 95 % CI [1.40-3.67]) for female sex and (OR = 1.02 95 % CI [1.01-1.04]) for every increase in age by 1-year. We reported a younger average age than other countries and less complex ablations. In addition, we reported 2 independent predictors of atrioventricular nodal reentry tachycardia in patients presenting with undifferentiated supraventricular tachycardia. Larger studies including multiple centers should be performed to confirm our findings.

Radiofrequency catheter ablation reduces the severity of anxiety in patients with atrioventricular nodal reentry tachycardia, regardless of age, sex, tachycardia type, and laboratory findings

Radiofrequency catheter ablation reduces the severity of anxiety in patients with atrioventricular nodal reentry tachycardia, regardless of age, sex, tachycardia type, and laboratory findings

Two decades of SVT ablation in Denmark: a trend towards higher age, more comorbidity, and less prior use of antiarrhythmic and rate-limiting pharmacotherapy—a nationwide registry-based Danish study

Background and aimsTrends in patient selection and use of pharmacotherapy prior to catheter ablation (CA) for supraventricular tachycardia (SVT) are not well described. This study examined temporal trends in patients undergoing first-time CA for regular SVT, including atrioventricular nodal re-entry tachycardia (AVNRT), accessory pathways (APs), and ectopic atrial tachycardia (EAT) on a nationwide scale in Denmark in the period 2001–2018.Methods and resultsUsing Danish Nationwide registers, 9959 patients treated with first-time CA for SVT between 2001 and 2018 were identified, of which 6023 (61%) received CA for AVNRT, 2829 (28%) for AP, and 1107 (11%) for EAT. Median age was 55, 42, and 55 in the AVNRT, APs, and EAT group, respectively. The number of patients receiving CA increased from 1195 between 2001 and 2003 to 1914 between 2016 and 2018. The percentage of patients with a CHA2DS2-VASc score ≥ 2 increased in all patient groups. The number of patients who underwent CA with no prior use of antiarrhythmic- or rate limiting medicine increased significantly, though prior use of beta-blockers increased for AVNRT patients. Use of verapamil decreased in all three SVT groups (P < 0.05). Use of amiodarone and class 1C antiarrhythmics remained low, with the highest usage among EAT patients.ConclusionBetween 2001 and 2018, CA was increasingly performed in patients with SVT, primarily AVNRT- and EAT patients. The burden of comorbidities increased. Patients undergoing CA without prior antiarrhythmic- or rate-limiting drug therapy increased significantly. Use of beta-blockers increased and remained the most widely used drug.Graphical

Low voltage mapping in atrio-ventricular nodal reentry tachycardia ablation: safety and efficacy in a single center experience

Abstract Background Atrio-ventricular nodal reentry tachycardia (AVNRT) is one of the most common supraventricular arrhythmias. Transcatheter ablation is the first-choice strategy for its treatment. Despite various ablation techniques, using different signal analyses and different energy sources, the reported incidence rate of AVNRT recurrences and high-grade or complete atrioventricular block are about 5% and 1% respectively. Voltage mapping for slow pathway localization is a novel technique for the treatment of AVNRT, that may increase procedural safety and effectiveness, particularly in pediatric patients. Purpose To evaluate the safety and efficacy of ablation of slow conduction pathway identified via three-dimensional voltage mapping of Koch’s triangle. Methods 108 consecutive patients (45% male, mean age 58.6±15.4 years) scheduled for AVNRT ablation in our center underwent three-dimensional voltage mapping of the right atrial septum and Koch’s triangle. Voltage map was aimed at detecting an area of low voltage (voltage bridge) below the His bundle (adjusting the high-voltage slider to 1,5 mV), corresponding to the slow conduction pathway. Focusing on this target, we evaluated the number of radiofrequency (RF) pulses and RF time application for effective ablation of the slow conduction pathway defined by accelerated junctional rhythm (AJR) induction during RF delivery and absence of post-ablative AVNRT inducibility. After RF ablation, all patients underwent clinical evaluation every 3 months to identify AVNRT recurrences. Results Voltage mapping was performed in all patients. The mean duration of mapping was 5.7±3.8 minutes. In all patients, a low voltage bridge could be identified. Using this target, RF was delivered until AJR was elicited (mean number of RF pulses at 30W, 50°C = 1.5±1.1; mean time to AJR: 25±12 s). After successful ablation of the slow conduction pathway, AVNRT was no more inducible. No atrioventricular conduction defect (atrioventricular block of any grade) occurred after RF ablation in any patient (AH pre vs. AH post: 148.5±22.8 ms vs. 153.6±17.8 ms, p=n.s.; HV pre vs. HV post: 20.5±18.7 ms vs. 21.8±17.3 ms, p=n.s.; Wenkebach point pre vs. Wenkebach point post: 320.4±45.3 ms vs. 326.2±38.7 ms, p=n.s.). All patients were discharged without antiarrhythmic drug therapy. Overall, during a 2-year follow up, 4 patients had a recurrence of AVNRT (incidence rate of recurrences: 0.025/year). Conclusions Voltage mapping can easily identify the low voltage bridge area of Koch’s triangle as a target for slow pathway ablation. RF ablation of the slow pathway identified in this way is safe and effective. Success in slow pathway ablation can be achieved with a low number of very precise RF pulses. This approach can prevent the risk of ablation-related atrioventricular conduction defects and reduce the risk of AVNRT recurrences.

Digital health in the EP lab: Initial experience using remote access and technical support for complex ablation procedures

Abstract Aims/Objectives Three-D electroanatomical mapping (EAM) systems are a prerequisite for treatment of complex arrhythmias. Until date, the EAM system is operated by qualified staff or a field technical engineer (FTE) from the control room. Novel technology allows for remote access (RA) of the EAM from anywhere in the world. RA increases the flexibility of the EP lab, reduces travel time for the FTE and overcomes hospital access limitations e. g. during the COVID-19 pandemic. We report on the safety and feasibility of remote operation of the EAM for complex ablation procedures. Methods RA mapping was achieved by combining the EAM software with an integrated audiovisual solution for remote support. Communication between the operator and the remote support was achieved using internet-based headphones in the RA group. The 3D EAM system was controlled exclusively from home office. In the conventional group (CG), EAM was exclusively controlled from the control room in the EP lab. Ablation procedures were performed as per institutional standard. Results We investigated 50 RA assisted consecutive electrophysiological procedures from 09/2022 to 02/2023 in our University Heart Center. We compared a group of patients undergoing ablation procedures with RA assistance (28/50 (56%) patients were male, median age: 66.5 yrs [IQR 56, 76], BMI: 25.2 kg/m2 [IQR 22, 30]) with a control group (31/50 (62%) male, median age: 66.5 yrs [IQR 54, 78], BMI 28.2 kg/m2 [IQR 24, 30], p &amp;gt; 0.05 for all). Ablation procedures were matched in both groups: 20 pulmonary vein isolations (3 paroxysmal, 17 persistent atrial fibrillation ), 4 cavotricuspidal isthmus ablations, 13 ablations of atrial tachycardia, 1 premature ventricular complex ablation, 3 of ventricular tachycardia, 2 AV reentry tachycardia and 7 AV-node reentry tachycardia cases. In the RA group, the 3D EAM system was controlled exclusively from home office in all patients. In one patient, the internet based headphone connection was instable. Therefore, the communication was established via a conventional smartphone. No other technical issue was noted. No switch to in house support was required. There were no major complications observed. Procedural data (total procedure time median 100 min [IQR 76, 120] vs. control group 86 min [IQR 60, 110], total fluoroscopy time (median 9.1 min [IQR 6, 13] vs. control group 8.7 min [IQR 5, 12], p &amp;gt; 0.05) were comparable to previous procedures without RA. Due to RA travel time could be reduced by 139 hr in total in comparison to the control group. Conclusions RA for EAM of any arrhythmia is feasible and safe in this single center study. Procedural data were comparable to previous procedures. In the future, this new solution might have a great impact on facilitating EP procedures.Table procedural data

Abstract 13443: Dead Antegrade Fast Pathway: A Dilemma for Atrioventricular Nodal Re-Entry Tachycardia Ablation

Background: Catheter ablation is the first-line treatment option for symptomatic atrioventricular nodal re-entry tachycardia (AVNRT). Ablation of the slow pathway is preferred over the fast pathway in Typical AVNRT, given that it has a lower risk of heart block. Still, baseline conduction abnormalities and findings on the Electrophysiology (EP) study can alter the ablation strategy. Case: We report a case of a 61-year-old male who was referred to EP clinic for symptomatic suspected AVNRT. His baseline electrocardiogram (EKG) showed normal sinus rhythm with PR prolongation, right bundle branch block, and left anterior fascicular block. EP study was performed, which showed prolonged AH interval with normal HV interval (Figure 1). Typical AVNRT was induced with a premature atrial complex; there was no AV nodal jump before the tachycardia, but it had a long AH interval (Figure 2). There was no evidence of pre-excitation. Discussion: Since there was no antegrade conduction through the fast pathway, conventional slow pathway ablation was not viable as it would make the patient pacemaker (PM)-dependent. Even ablating the fast pathway, though not PM-dependent, would still put him at risk for complete heart block, especially when his antegrade conduction via the slow pathway was unreliable. Hence PM was discussed with the patient before ablation. The fast pathway was mapped and ablated (Figures 3, 4, and 5) without complication, and PM was implanted. Conclusion: This case emphasizes the role of fast pathway ablation in symptomatic AVNRT in patients with conduction abnormalities and the importance of EP study to see the need for PM post-ablation.

Long-term results of catheter ablation for AV nodal reentry tachycardias and accessory pathways

Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia in patients with accessory pathways (AP) are common supraventricular tachycardias. High long-term efficacy of about 97% (AVNRT) and 92% (AP) has been observed in children and adults. The risk of occurring atrioventricular block is low (0.4-0.8% during AVNRT, 0.1-0.2% for AP). Catheter ablation shows alower efficacy of 87-93% and elevated atrioventricular block risk up to 10% in patient groups with complex congenital heart disease. Nonsynchronized ventricular activation during preexcitation or permanent reentrant tachycardias can induce heart failure, and remission of left ventricular function can be expected in > 90% after successful catheter ablation. Therefore, catheter ablation is the long-term therapy of choice for AVNRT and AP with high efficacy and safety for most patient populations.

Atrioventricular nodal reentry tachycardia treatment using CARTO 3 V7 activation mapping: a new era of slow pathway radiofrequency ablation is under coming.

Slow pathway (SP) ablation is the cornerstone for atrioventricular nodal reentry tachycardia (AVNRT) treatment, and a low-voltage bridge offers a good target during mapping using low x-ray exposure. We aimed to assess a new tool to identify SP by activation mapping using the last CARTO3® version, i.e., CARTO PRIME® V7 (Biosense Webster, Diamond Bar, CA, USA). Right atrial septum and triangle of Koch 3D-activation map were obtained from intracardiac contact mapping during low x-ray CARTO 3® procedure. In 60 patients (mean age 60.3 ± 14.7, 61% females) undergoing ablation for AVNRT, an automatic activation map using a DECANAV® mapping catheter and CARTO® Confidense™, Coherent, and FAM DX software modules were obtained. The SP was identified in all patients as the latest atrioventricular node activation area; RF catheter ablation (RFCA) in that region elicited junctional beats. The mean procedural time was 150.3 ± 48.3 min, the mean fluoroscopy time exposure was 2.9 ± 2 min, the mean dose-area product (DAP) was 16.5 ± 2.7 cGy/cm2. The mean number of RF applications was 3.9 ± 2, the mean ablation index was 428.6 ± 96.6, and the mean contact force was 8 ± 2.8 g. There were no adverse event during the procedure, and no AVNRT recurrences occurred during a mean follow-up of 14.3 ± 8.3 months. Ablation of the SP by automatic mapping using Confidense™, Coherent, and FAM DX software modules is an innovative, safe, and effective approach to AVNRT ablation. The CARTO3® V7 system shows on a 3D map the latest AV node activation area during sinus rhythm allowing low fluoroscopy time and highly effective RFCA.

The value of 12-lead electrocardiography in predictive mechanism of regular narrow qrs complex paroxysmal supraventricular tachycardias

Background: Paroxysmal supraventricular tachycardia (NNKPTT) is the most common clinical occurrence, affecting hemodynamics and causing symptoms of palpitations and dyspnea in patients. Of the mechanisms that cause paroxysmal supraventricular tachycardia, atrioventricular nodal re-entry tachycardia (AVNRT), atrioventricular re-entrant tachycardia (AVRT), and atrial tachycardia (AT) are the most common and difficult to distinguish each other. The electrocardiogram can be used to confirm and diagnose the mechanism of paroxysmal supraventricular tachycardia. [1]&#x0D; Objectives: to evaluate the predictive ability of the 12-lead electrocardiogram to predict the mechanism of paroxysmal supraventricular tachycardia with regular narrow QRS complex. Methods: cross-sectional descriptive method for 92 patients.&#x0D; Results: prevalence of paroxysmal supraventricular tachycardia mechanisms in the study was: atrioventricular nodal reentry tachycardia accounted for 69.6%; atrioventricular reentry tachycardia accounted for 27.2%; atrial tachycardia accounted for 3.4%. In univariate regression analysis, the ECG criteria with 95% CI of OR not containing a value of 1 were: clear P' wave, pseudo r' wave in V1, ST-T segment change, electrical alternation , pseudo r wave in aVR. In the multivariable regression model, the independent predictors AVNRT with AVRT are clear P' waves and ST–T segment changes.

Electroanatomical Mapping System-Guided vs. Intracardiac Echocardiography-Guided Slow Pathway Ablation: A Randomized, Single-Center Trial.

Radiofrequency (RF) catheter ablation is an effective treatment option for targeting the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT). Previous data suggested that using intracardiac echocardiography (ICE) guidance could improve procedural outcomes when compared to using fluoroscopy alone. In this prospective study, we aimed to compare the effectiveness of an electroanatomical mapping system (EAMS)-guided approach with an ICE-guided approach for SP ablation. Eighty patients undergoing SP ablation for AVNRT were randomly assigned to either the ICE-guided or EAMS-guided group. If the procedural endpoint was not achieved after 8 RF applications; patients were allowed to crossover to the ICE-guided group. The ICE-guided approach reduced the total procedure time (61.0 (56.0; 66.8) min vs. 71.5 (61.0; 80.8) min, p < 0.01). However, the total fluoroscopy time was shorter (0 (0-0) s vs. 83.5 (58.5-133.25) s, p < 0.001) and the radiation dose was lower (0 (0-0) mGy vs. 3.3 (2.0-4.7) mGy, p < 0.001) with EAMS-guidance. The ICE-guided group had a lower number of RF applications (4 (3-5) vs. 5 (3.0-7.8), p = 0.03) and total ablation time (98.5 (66.8-186) s vs. 136.5 (100.5-215.8) s, p = 0.02). Nine out of 40 patients (22.5%) in the EAMS-guided group crossed over to the ICE-guided group, and they were successfully treated with similar RF applications in terms of number, time, and energy compared to the ICE-guided group. There were no recurrences during the follow-up period. In conclusion, the utilization of ICE guidance during SP ablation has demonstrated notable reductions in procedural time and RF delivery when compared to procedures guided by EAMS. In challenging cases, an early switch to ICE-guided ablation may be the optimal choice for achieving successful treatment.

Atrioventricular Conduction: Physiology and Autonomic Influences.

Atrioventricular (AV) nodal conduction is decremental and very prone to alterations in autonomic tone. Conduction through the His-Purkinje system (HPS) is via fast channel tissue and typically not that dependent on autonomic perturbations. Applying these principles, when the sinus rate is stable and then heart block suddenly occurs preceded by even a subtle slowing of heart rate, it typically is caused by increased vagal tone, and block occurs in the AV node. Heart block with activity strongly suggests block in the HPS. Enhanced sympathetic tone and reduced vagal tone can facilitate induction of both AV and atrioventricular node reentry.

Sex Related Differences in Electrocardiography.

Since its implementation into the clinical medicine by Willem Einthoven electrocardiography had become one of crucial diagnostic method in cardiology. In spite of this fact effects of gender differences on parameters of electrocardiographic recordings started to be studied only recently. Sex related differences in physiological ECG are only minimal in childhood but there are developing during adolescence reflecting rapidly evolving differences particularly in hormonal secretion and activity of an autonomic nervous system. The heart rate is approximately 7 % higher in women than in men, PQ and QRS intervals are longer in men while QT interval is longer in women. The ST segment in females is flatter but generally the sex-related differences in ST-T waveform patterns are relatively very small with higher level of ST segment and taller T wave in men. The effects of sex-related differences, including sex hormones, on cardiac cell injury and death and their influence in determining rhythmogenesis and action potential configuration and conduction play an important role in clinics. Women have a higher prevalence of sick sinus syndrome, inappropriate sinus tachycardia, atrioventricular nodal reentry tachycardia, idiopathic right ventricular tachycardia, and arrhythmic events in the long QT syndrome. In contrast, men have a higher prevalence of atrioventricular block, carotid sinus syndrome, atrial fibrillation, supraventricular tachycardia due to accessory pathways, Wolff-Parkinson-White syndrome, reentrant ventricular tachycardia, ventricular fibrillation and sudden death, and the Brugada syndrome.