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A 66-year-old woman with palpitations was referred to our center for catheter ablation due to drug-refractory, common type atrioventricular nodal tachycardia (AVNRT). A selective slow pathway ablation was attempted. A fast junctional rhythm with transient ventriculoatrial block followed by transient prolongation of the A–H interval occurred immediately after the radiofrequency (RF) application at the coronary sinus ostium (CSOS) level. To assess the location of the fast pathway and His bundle, we sought to visualize the anatomy of the triangle of Koch (TOK) by three-dimensional computed tomography (CT).

This study describes a triathlete with effort-provoked atrioventricular nodal re-entrant tachycardia (AVNRT), diagnosed six years ago, who ineffectively controlled his training load via heart-rate monitors (HRM) to avoid tachyarrhythmia. Of the 1800 workouts recorded for 6 years on HRMs, we found 45 tachyarrhythmias, which forced the athlete to stop exercising. In three of them, AVNRT was simultaneously confirmed by a Holter electrocardiogram (ECG). Tachyarrhythmias occurred in different phases (after the 2nd–131st minutes, median: 29th minute) and frequencies (3–8, average: 6.5 times/year), characterized by different heart rates (HR) (150–227 beats per minute (bpm), median: 187 bpm) and duration (10–186, median: 40 s). Tachyarrhythmia appeared both unexpectedly in the initial stages of training as well as quite predictably during prolonged submaximal exercise—but without rigid rules. Tachyarrhythmias during cycling were more intensive (200 vs. 162 bpm, p = 0.0004) and occurred later (41 vs. 10 min, p = 0.0007) than those during running (only one noticed but not recorded during swimming). We noticed a tendency (p = 0.1748) towards the decreasing duration time of tachycardias (2014–2015: 60 s; 2016–2017: 50 s; 2018–later: 37 s). The amateur athlete tolerated the tachycardic episodes quite well and the ECG test and echocardiography were normal. In the studied case, the HRM was a useful diagnostic tool for detecting symptomatic arrhythmia; however, no change in the amount, phase of training, speed, or duration of exercise-stimulated tachyarrhythmia was observed.

A 32‐year‐old woman underwent radiofrequency catheter ablation of narrow QRS tachycardia that was terminated with intravenous adenosine. [ABSTRACT FROM AUTHOR]

The article describes the case of a 40-year-old female diagnosed with dual tachycardia with 1:2 tachycardia and atrioventricular (AV) nodal reentrant tachycardia with retrograde 1:2 response. Topics include twelve-lead electrocardiogram during sinus rhythm, the possibility of dual AV nodal pathways with simultaneous fast and slow conduction, and the relationship between the His potentials of the fast and slow pathways.

The article presents a case study of a 20-year-old woman who was referred to radiofrequency catheter ablation of narrow QRS tachycardia for incomplete right bundle branch block (RBBB) morphology. It discusses the diagnosis of changes in QRS morphology with shortening of hisio-ventricular interval after electrophysiology study along with ventricular overdrive pacing (VOD).

The article presents a case study of A70-year-oldmanwith a history of complete AVblock status post dual chamber permanent pacemaker implantation presented to the emergency department complaining of worsening fatigue and palpitations. The recording of Electrocardiography was interpreted as atrial tachycardia; pacemaker-mediated tachycardia; or atrioventricular nodal reentrant tachycardia. Tachycardia was terminated with an incidental ventricular pacing from pacemaker.

Objectives: We sought to investigate by speckle tracking technique the longitudinal function of the left atrium in patients with reentrant paroxysmal supraventricular tachycardia with narrow QRS complex, in order to identify early functional changes that these arrhythmias may induce even when paroxysmal. Methodology: 23 patients with reentrant paroxysmal supraventricular tachycardia with narrow QRS complex have been evaluated by echocardiographic speckle tracking techniques in the first week after pharmacological conversion to sinus rhythm. The subsequent electrophysiology study identified 13 of these patients with atrioventricular nodal reentrant tachycardia (AVNRT), and 10 patients with atrioventricular reentrant tachycardia (AVRT). The echocardiographic examinationby speckle tracking technique was performed considering current standards, in apical 4 and 2 chamber views, using narrow sector angles, single focus imaging and optimal depth. Left atrium contour was traced defining the region of interest and the longitudinal strain was obtained for 12 segments. The average longitudinal strain obtained in each apical view was represented by a curve allowing the peak-strain quantification. Results: The peak longitudinal strain values assessed in the apical 4 chamber view in the AVNRT group (most frequent value 16% (mod = 16%)) and in the AVRT group (most frequent value 8.5% (mod = 8.5%)(were significantily lower than the peak longitudinal strain values measured in the control group (most frequent value 39% (mod = 39%)), with no significant difference in peak longitudinal strain between the two different types of tachycardia groups (F = 30,19; p < 0,0001). In a similar manner, the peak longitudinal strain measured in the apical 2 chamber view were significantly lower in the tachycardia group than in the control group (most frequent value in the control group 38% (mod = 38%), in the AVNRT group 19% (mod = 19%), in the AVRT group 19% (mod = 19%)(F = 36,68; p < 0,0001). Conclusions: Tachycardia irrespective of the type - AVNRT or AVRT results in the impairment of left atrial mechanical function. The peak positive strain is significantly lower in patients with tachycardia, denoting a decrease in left atrial compliance in these patients compared to the control group. [ABSTRACT FROM AUTHOR]

Purpose: Slow pathway modulation is the treatment of choice in patients with atrioventricular nodal reentrant tachycardia (AVNRT). No comparative data on ablation strategies exist. Therefore, we sought to compare two common ablation approaches.Methods: We analyzed prospective ablation databases of two high-volume tertiary centers (> 1000 ablations/year) using either 30 or 50 W for slow pathway modulation from 2012 to 2013. We analyzed procedural characteristics as well as short- and long-term outcomes. Mean follow-up was 36 ± 9 months.Results: Six hundred thirty-four patients (50 W center: n = 342, 30 W center: n = 292) were ablated. Slow pathway modulation was successful in 99% in both groups (p = ns). Periprocedural AV block occurred in nine patients (2.6%) in the 50 W and five patients (1.7%) in the 30 W group (p = 0.59), respectively. We documented no permanent higher-degree AV block. The number of RF lesions and seconds of RF delivery was significantly less in the 50 W group (p = 0.04 for number of lesions; p < 0.001 for seconds). AVNRT recurrence was similar (p = 0.23). In males, significantly fewer recurrences accrued in the 50 W group (p = 0.04), while in females less transient AV blocks occurred during the procedure with 30 W (p = 0.07).Conclusions: The 30 and 50 W target power approaches for slow pathway modulation are highly effective and safe. Significantly, fewer RF duration was necessary to modulate the slow pathway with higher power output (50 W). Our subgroup analysis suggests that males and females might benefit most from different modulation approaches. [ABSTRACT FROM AUTHOR]

Aims: In previous retrospective studies, it was shown that the presence of residual single atrioventricular node (AVN) echoes with an echo zone longer than 30 ms may increase the rate of recurrence after radiofrequency ablation (RFA) of slow pathway in patients with AVN reentrant tachycardia (AVNRT). Based on that, some centres perform additional RFA in these patients. However, this opinion has never been tested prospectively and many centres do not perform re-ablation in these patients. The purpose of this study was to test whether persistence of a single AVN echo over a wide echo zone is a valid end point for RFA.Methods and results: In this prospective study, 576 patients who had a non-inducible arrhythmia post-RFA of AVNRT were divided into those with a remnant echo over a wide echo zone (case group) and those reaching classical end points (control group). The primary end point of the study was recurrence and patients were followed for 34.5 ± 18.8 months. In the control group (n = 510), 14 patients (2.7%) had a recurrence while no recurrence was seen in the case group (n = 66) (final cure rate, 97.3 vs. 100%; difference, 2.7%; upper bound of the 98% CI, 0.0488; P < 0.0001 for non-inferiority). Two complete heart blocks (0.4%) happened in the control group and none in the case group (P = 0.784).Conclusion: Non-inducibility in the presence of a wide echo window is non-inferior to non-inducibility in the presence of narrow echo window or no AVN echoes. In general, the presence of a single echo beat is not an indication for further ablation and this applies for both narrow and wide windows. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation of slow-pathway (CaSP) has been reported to be effective in patients with dual atrioventricular nodal conduction properties (dcp-AVN) and clinical ECG documentation but without the induction of tachycardia during electrophysiological studies (EPS). However, it is unknown whether CaSP is beneficial in the absence of pre-procedural ECG documentation and without the induction of tachycardia during EPS. The aim of this study was to evaluate long-term results after a "pure" empirical CaSP (peCaSP). Methods: 334 consecutive patients who underwent CaSP (91 male, 47.5 ± 17.6 years) were included in this study. Sixty-three patients (19%) who had no pre-procedural ECG documentation, and demonstrated dcp-AVN with a maximum of one echo-beat were assigned to the peCaSP group. The remaining 271 patients (81%) were assigned to the standard CaSP group (stCaSP). Clinical outcomes of the two groups were compared, based on ECG documented recurrence or absence of tachycardia and patients' recorded symptoms. Results: CaSP was performed in all patients without any major complications including atrioventricular block. During follow-up (909 ± 435 days), 258 patients (77%) reported complete cessation of clinical symptoms. There was no statistically significant difference in the incidence of AVNRT recurrence between the peCaSP and stCaSP groups (1/63 [1.6%] vs 3/271 [1.1%], P = 0.75). Complete cessation of clinical symptoms was noted significantly less frequently in patients after peCaSP (39/63 [62%] vs 219/271 [81%], P = 0.0013). The incidence of non-AVNRT atrial tachyarrhythmias (AT) was significantly higher in patients after peCaSP (5/63 [7.9%] vs 1/271 [0.4%], P = 0.0011). Conclusion: A higher incidence of other AT and subjective symptom persistence are demonstrated after peCaSP, while peCaSP improves clinical symptoms in 60% of patients with non-documented on-off tachycardia. [ABSTRACT FROM AUTHOR]

Abstract: Background: Atrioventricular nodal reentrant tachycardia (AVNRT) is a common tachyarrhythmia substrate in children, which is successfully treated by catheter ablation using radiofrequency or cryothermal energy. In recent years, cryoablation (Cryo) using electroanatomical system guidance is more commonly preferred for use in children in order to decrease the risk of an atrioventricular block. However, there are concerns regarding the long‐term efficacy of Cryo in treating AVNRT. We aimed to evaluate the feasibility, safety, and long‐term efficacy of Cryo for AVNRT in children. Methods and results: A total of 275 consecutive children above 4 years of age diagnosed with AVNRT were included in our study. The EnSite system (St. Jude Medical, Inc., St. Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The study included 275 patients (148 females, age: 11.9 ± 3.6 years) undergoing catheter ablation for AVNRT from July 2012 to September 2016. Acute success was obtained in all (100%) patients with a mean procedure time of 140 ± 44 minutes. Fluoroscopy was used in only 12 (4.4%) patients. During a follow‐up time of 25.6 ± 13.5 months (median: 23 months), AVNRT recurred in 12 of 279 (4.4%) of the patients. Age, sex, number of Cryo lesions, and catheter tip size (6‐mm vs 8‐mm) were not predictive for recurrence. In nine patients, a repeat ablation was successfully performed with cryoenergy. Conclusions: Cryo for AVNRT is a safe and effective procedure with excellent long‐term outcomes. The use of electroanatomical systems during ablation significantly decreases exposure to fluoroscopy without compromising success. [ABSTRACT FROM AUTHOR]

Abstract: Background: Ablation is an effective treatment for atrioventricular nodal reentrant tachycardia (AVNRT). The occurrence of junctional ectopic rhythm (JER), including junctional ectopic tachycardia, following AVNRT ablation has been described as an extremely rare phenomenon, but may be underestimated. We aimed to determine the incidence of JER following AVNRT ablation within our institution, as well as that reported in the literature via an extensive review. Methods: We reviewed our adult ablation institutional experience for the occurrence of JER after AVNRT ablation from 2009 to 2016. Additionally, we conducted an extensive literature search using different databases looking for AVNRT ablation case series. The individually reported complications of these studies were reviewed, with a primary endpoint defined as the occurrence of JER shortly after AVNRT ablation. The study was approved by our institutional review board. Results: Our institutional data revealed 6/126 patients (prevalence 4.8%) developed non‐preexisting JER post‐AVNRT ablation. Four patients were asymptomatic. Two patients had persistent symptoms lasting over a year, with one patient requiring repeat ablation. The literature review included 149 adult and pediatric studies. There were three cases of reported JER, out of a total of 37,541 patients (31,768 adults and 5,773 pediatric; prevalence 0.008%). The three JER patients were pediatric, and all required further therapeutic intervention. Conclusion: JER might be an underreported complication of AVNRT ablation. It seems most often to be transient and self‐limited, occurring days to weeks after ablation, but may also be debilitating, requiring more aggressive management. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Stochastic damage of the ionizing radiation to both patients and medical staff is a drawback of fluoroscopic guidance during catheter ablation of cardiac arrhythmias. Therefore, emerging zero‐fluoroscopy catheter‐guidance techniques are of great interest. Methods and results: We investigated, in a prospective pilot study, the feasibility and safety of the cryothermal (CA) slow‐pathway ablation in patients with symptomatic atrioventricular‐nodal‐re‐entry‐tachycardia (AVNRT) using solely intracardiac echocardiography (ICE) for endovascular and endocardial catheter visualization. Twenty‐five consecutive patients (mean age 55.6 ± 12.0 years, 17 female) with ECG‐documentation or symptoms suggesting AVNRT underwent an electrophysiology study (EPS) in our laboratory utilizing ICE for catheter navigation. Supraventricular tachycardia was inducible in 23 (92%) patients; AVNRT was confirmed by appropriate stimulation maneuvers in 20 (80%) patients. All EPS in the AVNRT subgroup could be accomplished without need for fluoroscopy, relying solely on ICE‐guidance. CA guided by anatomical location and slow‐pathway potentials was successful in all patients, median cryo‐mappings = 6 (IQR:3–10), median cryo‐ablations = 2 (IQR:1–3). Fluoroscopy was used to facilitate the trans‐septal puncture and localization of the ablation substrate in the remaining 3 patients (one focal atrial tachycardia and two atrioventricular‐re‐entry‐tachycardias). Mean EPS duration in the AVNRT subgroup was 99.8 ± 39.6 minutes, ICE guided catheter placement 11.9 ± 5.8 minutes, time needed for diagnostic evaluation 27.1 ± 10.8 minutes, and cryo‐application duration 26.3 ± 30.8 minutes. Conclusions: ICE‐guided zero‐fluoroscopy CA in AVNRT patients is feasible and safe. Real‐time visualization of the true endovascular borders and cardiac structures allow for safe catheter navigation during the ICE‐guided EPS and might be an alternative to visualization technologies using geometry reconstructions. [ABSTRACT FROM AUTHOR]

Introduction: Radio frequency ablation of the slow pathway has become first-line therapy for the elimination of AV nodal reentrant tachycardia (AVNRT). Slow pathway ablation is guided by a combination of fluoroscopic landmarks, electrogram morphology, and the induction of accelerated junctional rhythm (JR) during the application of radiofrequency energy. Although JR occurs usually during slow pathway ablation of AVNRT, the pattern of JR has not been adequately studied.13 Aim of the study: To investigate in detail the characteristics of junctional rhythm occurring during radiofrequency ablation of atrioventricular nodal reentrant tachycardia AVNRT among Egyptians. Methods: This study included 30 patients who underwent electrophysiological study for narrow complex supraventricular regular tachycardia which revealed to be AVNRT. Results: Thirty (100%) patients showed induction of junctional rhythm at the successful ablation sites. JR was a very sensitive predictor of successful ablation but not so specific with specificity of 60%. Sex patterns of JR were observed. The most common pattern of JR was sinus–junctional–junctional (SJJ) while sinus–junctional-block (SJB) was the least. The most specific pattern for effective ablation was junctional–junctional–junctional (JJJ), while intermittent burst was the least. P value is 0.001 i.e. highly significant. Conclusion: Junctional rhythm is a sensitive predictor of successful ablation. The pattern of JR is a useful predictor of successful ablation. Egyptian population has distinctive patterns of JR during AVNRT ablation.

Introduction: Right ventricular entrainment represents a useful tool for differentiating atrioventricular nodal re-entrant tachycardia (AVNRT) from orthodromic re-entrant tachycardia (ORT) using an accessory pathway. However, inability to entrain PSVT by pacing can be observed in some patients. Aim of study: Assessing whether the resetting response to SVT by single or double right ventricular extra-stimuli is a useful maneuver to differentiate AVNRT from OAVRT by calculating the difference between the stimulus-atrial interval during resetting of SVT and the VA interval during SVT (SA–VA). Methods: Electrophysiological study was conducted with a calculation of the SA–VA interval after resetting of the tachycardia by ventricular extra stimulus and differential entrainment from RV apex and base, then comparing the two methods regarding sensitivity and specificity in differentiating AVNRT from OAVRT conducted on 25 patients. Results: Measuring the SA–VA interval after resetting of the tachycardia by an extra stimulus during the His refractoriness during the tachycardia showed in AVNRT a mean of 145.76 ± 31.53 and in OAVRT a mean ± SD of 91.52 ± 12.79 with a high statistical significance, with a cutoff point of 107 ms above which the SVT is expected to be AVNRT, and below which OAVRT. Using this technique could differentiate AVNRT from OAVRT with an overall sensitivity of 100% and specificity of 76.47%, in comparison to a specificity of 81.8% when using the technique of differential entrainment from RV apex and base. Conclusion: Resetting of SVT by ventricular extra-stimuli is a useful maneuver for differentiating AVNRT from ORT and is applicable even when entrainment is impossible.

Background: Atrioventricular nodal reentry tachycardia (AVNRT) is common in adults and often involves reentry through ≥2 atrioventricular nodal-atrial connections. Although AVNRT can be a trigger for atrial fibrillation (AF), we have observed new-onset AVNRT after AF ablation procedures.Objective: The purpose of this study was to determine whether ablation involving the septum or proximal coronary sinus (CS) during AF ablation may create a substrate favorable for AVNRT.Methods: Cases of ablation for persistent AF who required a repeat ablation procedure between 2009 and 2016 were reviewed for diagnosis of AVNRT.Results: Nine patients were identified; the mean age was 54 years, 7 (78%) were men, 2 with prior Cox-MAZE procedures, 5 had radiofrequency ablation (RFA) for AF, and 2 patients had both RFA and Cox-MAZE procedure. None of the patients with prior RFA had dual atrioventricular node physiology at baseline. All patients had evidence of atrial fibrosis in the septum or proximal CS, and 6 had undergone ablation either at the septum or the CS ostium/body, and the other 3 had received inferior mitral lines at a surgical MAZE procedure. All had typical AVNRT inducible that was abolished by slow pathway ablation, but 5 required ablation in the roof of the CS or on the mitral valve annulus.Conclusion: Ablation involving the septum or proximal CS may create a substrate favorable for AVNRT. These findings are consistent with the theory that the posteroseptal left atrium and its connections to the CS are critical for some forms of AVNRT. [ABSTRACT FROM AUTHOR]

Background: Cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) is associated with higher recurrence rates than radiofrequency ablation (RFA). Junctional tachycardia marks procedural success with RFA, but no such indicator exists for cryoablation.Objective: The purpose of this study as to determine the impact of voltage mapping plus longer ablation lesions on midterm success of cryoablation for children with AVNRT.Methods: We performed a single-center retrospective analysis of pediatric patients with AVNRT who underwent cryoablation from 2011 to 2015. Patients ablated using a standard electroanatomic approach (control) were compared with patients ablated using voltage mapping (voltage group). In the voltage group, EnSite NavX navigation and visualization technology (St Jude Medical, St Paul, MN) was used to develop a "bridge" of lower voltage gradients (0.3-0.8 mV) of the posteroseptal right atrium to guide cryoablation. Kaplan-Meier analysis was used to determine freedom from recurrence of supraventricular tachycardia.Results: In all, 122 patients were included (71 voltage, 51 control). There was no difference between groups regarding age, sex, or catheter-tip size. Short-term success was similar in both groups (98.5% voltage vs 92% control; P = .159), but recurrence rates were lower in the voltage group (0% vs 11%, P = .006). Follow-up time was shorter in the voltage group (15 ± 7 months vs 22 ± 17 months, P < .05). The 1-year freedom from recurrence was lower in the voltage group (100% vs 91.5%, P <.05). Ablation times were longer in the voltage group (43.7 ± 20.9 minutes vs 34.3 ± 20.5 minutes, P = .01), but overall procedure times were shorter in the voltage group (157 ± 40 minutes vs 198 ± 133 minutes; P = .018). No significant complication was seen in either group.Conclusion: Voltage gradient mapping and longer lesion time can decrease recurrence rates in pediatric patients with AVNRT. [ABSTRACT FROM AUTHOR]

Background Permanent AV-block is a recognized and feared complication of slow pathway modulation for AVNRT. We aimed to assess incidence of transient and permanent AV-block as well as consequences of transient AV-block in a large contemporary AVNRT ablation cohort. Methods We searched our single center prospective ablation database for occurrence of transient and permanent AV-block during slow pathway modulation between January 2004 and October 2015. We analyzed patients' and procedural characteristics as well as outcome of patients in whom transient or permanent AV-block occurred. Results Of 9170 patients who underwent a catheter ablation at our institution between January 2004 and October 2015, 2101 patients (64% women, mean age 50 ± 18 years) underwent slow pathway modulation. In three patients, permanent AV-block occurred during RF application. Additional two patients had transient AV-block that recovered (after a few minutes and 25 min), but recurred within two days of the procedure. All five patients underwent dual chamber pacemaker implantation (0.2%). Transient AV-block related to RF delivery occurred in 44 patients (2%). Transient mechanical AV-block occurred in additional 17 patients (0.8%). In 12 patients, ablation was continued despite transient AV-block. One of these patients developed permanent AV-block. Conclusion Permanent AV-block following slow pathway modulation is a rare event, occurring in 0.2% of patients in a large contemporary single center cohort. Transient AV-block is more frequent (2%). [ABSTRACT FROM AUTHOR]

Due to its safety profile, cryoablation (Cryo) for atrioventricular nodal reentrant tachycardia (AVNRT) is more commonly preferred over radiofrequency (RF) ablation in children in recent years. Recent studies demonstrated high long-term success rates comparable to radiofrequency ablation. The aim of this prospective study was to compare the efficacy and safety of an 8-mm-tip versus 6-mm-tip Cryo catheter in the treatment of AVNRT in children. A total of 125 consecutive patients over 10 years of age with AVNRT were included. EnSite system (St. JudeMedical, St Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The acute procedural success was 100% in both groups. The prodecure duration for the 8-mm-tip group was shorter (151.6 ± 63.2 vs. 126.6 ± 36.7 min, p < 0.01, respectively). Fluoroscopy was used in only 7 patients. The mean follow-up duration was 14.6 ± 8.4 months (median 13.5 months, min. 3 months and max. 27 months). The recurrence rate for AVNRT was also comparable between the two groups (6-mm tip: 9.6 vs. 8-mm tip: 8%). Cryo of AVNRT is a safe and effective procedure with comparable acute and mid-term follow-up success rates using 6-mm and 8-mm-tip catheters in children. In addition, procedure duration is shorter with an 8-mm-tip Cryo catheter. [ABSTRACT FROM AUTHOR]

Our approach to the ablation of atrioventricular nodal reciprocating tachycardia (AVNRT), the most common supraventricular tachycardia, is as follows: We first attempt ablation in the right atrial posteroseptum anterior to the coronary sinus ostium with a 4-mm non-irrigated tip catheter. If ablation within the triangle of Koch is unsuccessful with radiofrequency (RF), we switch to cryoablation and target a more superior (mid septal) region. We also utilize cryoablation if RF ablation produces transient VA block (absence of retrograde conduction during junctional rhythm) or a fast junctional rhythm (<350 msec). If cryoablation were to fail, or is not available, we would then suggest ablation within the coronary sinus targeting the roof (2-4 cm from the os) using a 3.5-mm irrigated tip catheter. If tachycardia were still inducible despite these measures, we would then proceed with transseptal puncture (given our greater experience with this over a retrograde aortic approach) and perform RF ablation along the posteroseptal left atrium and inferoseptal mitral annulus utilizing an irrigated tip catheter. In our experience, cryoablation reliably results in elimination of the slow pathway. The only left atrial ablation for AVNRT at our institution in the past year was performed because a patent foramen ovale allowed for rapid left atrial access, facilitating left atrial ablation of the slow pathway. [ABSTRACT FROM AUTHOR]

Purpose: Catheter ablation of the slow pathway is the most effective treatment for atrioventricular nodal reentrant tachycardia (AVNRT). Cryoenergy, compared to radiofrequency, relates to lower heart block risk but higher incidence of AVNRT recurrences. The aims of this study are to confirm the safety and efficacy of AVNRT cryoablation and to identify predictors of long-term recurrences.Methods: Among 241 patients undergoing AVNRT cryoablation, 239 (99.2%) experienced acute effective cryoablation of the slow pathway, and no procedure-related complications were reported.Results: After a follow-up of 44.9 ± 31.7 months, 28 (11.7%) patients presented AVNRT recurrences. A shorter preablation (p = 0.05) and postablation anterograde Wenckebach cycle length (p < 0.01), a shorter postablation atrioventricular node refractory period (p = 0.04), and persistence of the crossover sign (p = 0.03) were associated with higher incidence of long-term recurrences. Considering cooling dynamics, a longer time to reach temperature ≤-70 °C (p = 0.03) and a higher minimal temperature during ablation (p = 0.04) were related to recurrences. Patients without residual markers of dual AV node physiology (AH jump, single atrial echo beat, crossover) reported a lower recurrence rate (p = 0.05) compared to those without. At multivariate analysis, a longer time to -70 °C was the strongest independent predictor of long-term recurrence (OR 1.75, 95% CI 1.01-3.03, p = 0.04).Conclusions: AVNRT cryoablation is safe and effective. Long-term recurrence rate was 11.7%. An ablation approach directed to the complete elimination of dual AV node physiology, along with assessment of the tissue's cooling dynamics, holds the potential to improve long-term AVNRT cryoablation efficacy. [ABSTRACT FROM AUTHOR]

Background: During slow pathway modification for atrioventricular nodal reentrant tachycardia, heart block may occur if ablation cannot be stopped in time in response to high risk electrogram features (HREF)., Objectives: To develop an automatic algorithm to monitor HREF and terminate ablation earlier than human reaction., Methods: Digital electrogram data from 332 ablation runs from February 2020 to June 2022 were included. They were divided into training and validation sets which contained 126 and 206 ablation runs respectively. HREF in training set was measured. Then a program was developed with cutoff values decided from training set to capture all these HREF. Simulation ablation videos were rendered using validation set electrogram data. The videos were played to three independent electrophysiologists who each determined when to stop ablation. Timing of ablation termination, sensitivity, and specificity were compared between human and program., Results: Reasons for ablation termination in the training set include short AA time, short VV time, AV block and VA block. Cutoffs for the program were set to maximize program sensitivity. Sensitivity and specificity for the program in the validation set were 95.2% and 91.1% respectively, which were comparable to that of human performance at 93.5% and 95.4%. If HREF were recognized by both human and program, ablations were terminated earlier by the program 90.2% of times, by a median of 574 ms (interquartile range 412-807 ms, p  < 0.001)., Conclusion: Algorithmic-driven monitoring of slow pathway modification can supplement human judgement to improve ablation safety., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Tam, Lai, Chan, Au, Chan, Cheng and Yan.)

This report details the case of 17 year old identical twins who both presented with paroxysmal supraventricular tachycardia (PSVT). Electrophysiological studies revealed atrioventricular nodal reentry tachycardia (AVNRT) in both twins. Successful but technically challenging slow pathway ablation was performed in both twins. This is the first reported case of confirmed AVNRT in identical twins which adds strong evidence to heritability of the dual AV node physiology and AVNRT. A review of the current literature regarding PSVT in monozygotic twins is provided.

Nowadays paroxysmal AV nodal reentrant tachycardia (AVNRT) is one of the most widespread arrhythmias. In most cases AVRNT is a recurrent process, and it worsens the life quality of such patients, reduces their workability and increases the incidence of applying for medical help. Thus AVNRT today is of special attention among investigators. The interest of clinicians to the problem of cardiac arrhythmias is associated with permanent dissatisfaction with the results of antiarrhythmic therapy and also with the rapid development of the surgical methods of treatment, i.e. the use of radio frequency catheter ablation.

Background There are limited adult data suggesting the tachycardia cycle length (TCL) of atrioventricular reentry tachycardia (AVRT) is shorter than atrioventricular nodal reentry tachycardia (AVNRT), though little data exist in children. We sought to determine if there is a difference in TCL between AVRT and AVNRT in children. Methods A single-center retrospective review of children with supraventricular tachycardia (SVT) from 2000 to 2015 was performed. Inclusion criteria: Age ≤ 18 years, invasive electrophysiology study (EPS) confirming AVRT or AVNRT. Exclusion criteria: Atypical AVNRT, congenital heart disease, antiarrhythmic medication use at time of EPS. Data were compared between patients with AVRT and AVNRT via t-test, χ2 test, and linear regression. Results A total of 835 patients were included (12 ± 4 years, 52 ± 31 kg, TCL 321 ± 55 ms), 539 (65%) with AVRT (270 Wolff-Parkinson-White, 269 concealed pathways) and 296 (35%) with AVNRT. Patients with AVRT were younger (11.7 ± 4.1 years vs 13.0 ± 3.6 years, P < 0.001) and smaller (49 ± 22 kg vs 57 ± 43 kg, P < 0.001). In the baseline state, the TCL was shorter in AVRT than AVRNT (329 ± 51 ms vs 340 ± 60 ms, P = 0.04). In patients requiring isoproterenol to induce SVT, there was no difference in TCL (290 ± 49 ms vs 297 ± 49 ms, P = 0.26). When controlling for age, there was no difference in TCL between AVRT and AVNRT at baseline or on isoproterenol. The regression equation for TCL in the baseline state was TCL = 290 + 4 (age), indicating the TCL will increase by 4 ms above a baseline of 290 ms for each year of life. Conclusions When controlling for age, there is no difference in the TCL between AVRT and AVNRT in children. Age, not tachycardia mechanism, is the most significant factor in predicting TCL. [ABSTRACT FROM AUTHOR]

Purpose: Radiofrequency ablation (RFA) is considered the treatment of choice in cases of atrioventricular nodal reciprocating tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT). Published studies suggest a considerable time gap between the onset of the arrhythmia, correct diagnosis, and RFA which may reach 10-15 years. The cost of medical treatment during that period may be substantial. The aim of the study was to calculate the annual direct medical cost of medical treatment of patients with AVNRT and AVRT and identify potential factors influencing this cost.Methods: Based on the consumption of particular resources and the unit costs of services in 2013, we calculated the annual direct medical cost of care for patients with AVNRT and AVRT in Poland. We adopted the public payer's and societal perspectives. Data on health resources was collected with a structured questionnaire and medical records of patients scheduled for RFA. Additional analyses were performed to identify factors influencing this cost.Results: We enrolled 82 patients: mean age 43.9 ± 14.1 years old and mean symptom duration before the RFA 13.0 ± 11.3 years. The median annual cost of medical treatment was 546 USD [312-957], 411 € [278-786], and 616 USD [369-1044], 464 € [235-721], for the public payer and the common perspective, respectively, with hospitalizations being the main cost component. In multivariate analysis, only the age of the patient significantly influenced this cost.Conclusions: The annual cost of medical treatment of AVNRT or AVRT is substantial and dependent on the age of the patient rather than the severity of the arrhythmia (NCT01594814). [ABSTRACT FROM AUTHOR]

Purpose: Cryothermal ablation (CTA) for atrioventricular nodal reentrant tachycardia (AVNRT) is considered safer than radiofrequency ablation (RFA) since it eliminates the risk of inadvertent AV block. However, it has not been widely adopted due to high late recurrence rate (LRR). In an effort to improve LRR, we evaluated a new approach to cryothermal mapping (CTM): "time to tachycardia termination" (TTT).Methods: This single-center study had 88 consecutive patients who underwent CTA using TTT for AVNRT. The CTA catheter was positioned in sinus rhythm at the posteroseptal tricuspid annulus, and then AVNRT was induced. The CTA target site was identified by prompt tachycardia termination in ≤20 s during CTM. Procedural success was defined as no inducible AVNRT and ≤1 single AV nodal echoes.Results: Acute procedural success was achieved in 87 of 88 patients (98.9 %) and was similar to prior studies for both CTA and RFA. No permanent AV block was observed. LRR was 3.7 % at a mean follow-up of 19.7 months. LRR was equivalent to that commonly reported for RFA and improved when compared to conventional CTA.Conclusion: TTT for CTA of AVNRT provides enhanced safety and similar long-term efficacy when compared to RFA. Based upon this experience, TTT provides an enhancement to conventional CTA that appears to result in improved long-term outcomes. In light of these findings, it seems reasonable to undertake additional randomized trials to determine whether RFA or CTA using TTT is the optimal approach for the catheter ablation of AVNRT. [ABSTRACT FROM AUTHOR]

Background We aimed to analyze the results of retrograde aortic radiofrequency catheter ablation of left-sided accessory pathways in children. Methods Between January 2010 and September 2014, 25 children who underwent left-sided accessory pathway ablation with a retrograde aortic approach were evaluated retrospectively. Results The mean age of the patients was 11.09±3.71 years. Seventeen patients were male (68%). The mean procedure and fluoroscopy times were 71.54±21.05 min and 31.42±19.57 min, respectively. Radiofrequency energy was delivered with 41.38±15.32 W at 52.38±5.45 °C. Sixteen patients (64%) presented with manifest preexcitation and, 9 had concealed accessory pathways. The location of accessory pathway was left lateral in 16 patients, posteroseptal in 5, left anterolateral in 2, and left posterolateral and left posterior in the remaining 2. The acute success rate was 96%. The patients were followed for a mean of 16.68±18.01 months. There were 2 recurrences. No major complications were observed in the periprocedural period. One patient had groin hematoma, another one had transient severe headache and vomiting. Trivial mitral regurgitation was noted in a patient, which remained the same throughout follow-up. None of the patients developed new aortic regurgitation, pericardial effusion, or thrombi at the site of ablation. Conclusions The retrograde aortic approach can be safely employed with a high success rate for ablation of left-sided accessory pathways in children. [ABSTRACT FROM AUTHOR]

Dual atrioventricular nodal non-re-entrant tachycardia (DAVNNT), also known as 'double fire', has recently received more attention since it was demonstrated to mimic more common arrhythmias such as atrial premature beats, atrial fibrillation, and ventricular tachycardia. This is important, since mistaken differential diagnoses and the resulting therapeutic decisions have severe consequences for affected patients. DAVNNT is characterized by conduction characteristics of the atrioventricular (AV) node that leads to a double antegrade conduction of one sinoatrial nodal activity via the slow and fast AV nodal pathways. As a result, the most significant hint from an electrocardiogram (ECG) is a P wave followed by two narrow QRS complexes. Although DAVNNT is rather a rare arrhythmia, it now appears to be more common than previously thought. To date, 68 cases including 3 small single-centre observational studies accumulated over the last 5 years have demonstrated the feasibility and safety of radiofrequency catheter ablation for DAVNNT. Catheter ablation treats this arrhythmia effectively by modifying or eliminating slow pathway function. Here, we review the current state of DAVNNT knowledge systematically and address current challenges presented by this 'ECG chameleon from the AV node'. [ABSTRACT FROM AUTHOR]

Background: Radiofrequency (RF) catheter ablation is the procedure of choice for the potential cure of atrioventricular nodal reentrant tachycardia (AVNRT) with high success rates. We hypothesed that as a result of the close proximity of Koch’s triangle and low inter-atrial septal fibers, the RF ablation applied at this region may result in prolongation of inter-atrial conduction time (IACT). Methods: RF ablation of AVNRT was performed by conventional technique. IACT was measured before and 20 minutes after RF ablation during sinus rhythm. Number of ablations given and duration of ablation were noted. Results: The study group was consisted of 48 patients (36 [75%] female, 12 [25%] male, mean age 43.4 ± 14. 5 years). RF ablation was successful in all patients. Mean RF time was 4. 0 ± 3. 3 minutes and mean number of RF was 11. 9 ± 9, 8. The mean IACT was 70.1 ± 9.0 ms before ablation and 84.9 ± 12.7 ms after ablation, which demonstrated a significant prolongation (p

The present report describes “Frog sign” due to prominent jugular pulsations in the neck. This is seen in case of paroxysmal atrioventricular nodal reentrant tachycardia.