High-density mapping of Koch's triangle during sinus rhythm and typical atrioventricular nodal re-entrant tachycardia, integrated with direct recording of atrio-ventricular node structure potential.

BACKGROUND: The mechanism of typical slow-fast atrioventricular nodal re-entrant tachycardia (AVNRT) and its anatomical and electrophysiological circuit inside the right atrium (RA) and Koch's Triangle (KT) are not well known. OBJECTIVE: To identify the potentials of the compact AV node and inferior extensions and to perform accurate mapping of the RA and KT in sinus rhythm (SR) and during AVNRT, to define the tachycardia circuit. METHODS: Consecutive patients with typical AVNRT were enrolled in 12 Italian centers and underwent mapping and ablation by means of a basket catheter with small electrode spacing for ultrahigh-density mapping and a modified signal-filtering toolset to record the potentials of the AV nodal structures. RESULTS: Forty-five consecutive cases of successful ablation of typical slow-fast AVNRT were included. The mean SR cycle length (CL) was 784.1 ± 6 ms and the mean tachycardia CL was 361.2 ± 54 ms. The AV node potential had a significantly shorter duration and higher amplitude in sinus rhythm than during tachycardia (60 ± 40 ms vs. 160 ± 40 ms, p < .001 and 0.3 ± 0.2 mV vs. 0.09 ± 0.12 mV, p < .001, respectively). The nodal potential duration extension was 169.4 ± 31 ms, resulting in a time-window coverage of 47.6 ± 9%. The recording of AV nodal structure potentials enabled us to obtain 100% coverage of the tachycardia CL during slow-fast AVNRT. CONCLUSION: Detailed recording of the potentials of nodal structures is possible by means of multipolar catheters for ultrahigh-density mapping, allowing 100% of the AVNRT CL to be covered. These results also have clinical implications for the ablation of right-septal and para-septal arrhythmias.

A short RP tachycardia in congenitally corrected transposition. What is the mechanism?

A 51-year-old female with congenitally corrected transposition of great arteries (CCTGA), situs solitus, dextrocardia, atrial septal defect and persistent left superior vena cava underwent electrophysiology study for recurrent palpitations with documented narrow complex, short RP tachycardia. With a catheter in the region of the anterior mitral annulus, a His signal was recorded and HV interval was 35 msec. Tachycardia was induced with a ventricular extrastimulus. During the tachycardia there was 1:1 ventriculo-atrial conduction and central atrial activation with a VA interval of 20 msec. The recorded His signal could be seen after the QRS. What is the mechanism of the tachycardia?

Efficacy and safety between radiofrequency ablation and types of cryoablation catheters for atrioventricular nodal reentrant tachycardia: A Network Meta-analysis and Systematic Review.

INTRODUCTION: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia referred for ablation. Periprocedural conduction system damage was a primary concern during AVNRT ablation. This study aimed to assess the incidence of permanent atrioventricular (AV) block and the success rate associated with different types of catheters in slow pathway ablation. METHOD: A literature search was performed to identify studies that compared various techniques, including types of radiofrequency ablation (irrigated and nonirrigated) and different sizes of catheter tip cryoablation (4, 6, and 8-mm), in terms of their outcomes related to permanent atrioventricular block and success rate. To assess and rank the treatments for the different outcomes, a random-effects model of network meta-analysis, along with p-scores, was employed. RESULTS: A total of 27 studies with 5110 patients were included in the analysis. Overall success rates ranged from 89.78% to 100%. Point estimation showed 4-mm cryoablation exhibited an odds ratio of 0.649 (95%CI: 0.202-2.087) when compared to nonirrigated RFA. Similarly, 6-mm cryoablation had an odds ratio of 0.944 (95%CI: 0.307-2.905), 8-mm cryoablation had an odds ratio of 0.848 (95%CI: 0.089-8.107), and irrigated RFA had an odds ratio of 0.424 (95%CI: 0.058-3.121) compared to nonirrigated RFA. CONCLUSION: Our study found no significant difference in the incidence of permanent AV block between the types of catheters. The success rates were consistently high across all groups. These findings emphasize the potential of both RF ablation (irrigated and nonirrigated catheter) and cryoablation as viable options for the treatment of AVNRT, with similar safety and efficacy profile.

Analysis of intracardiac electrocardiogram during ill-sustained tachycardia - Door to a successful troubleshooting of 'unnecessary' defibrillator discharge.

A 50-year-old gentleman with old anterior wall myocardial infarction with implantable cardioverter defibrillator (ICD, Abbott Medical, Fortify ST VR 1235-40) presented with recurrent appropriate ICD shock. The ICD stored EGM indicated a possibility of supraventricular tachycardia (SVT) rather than ventricular tachycardia (VT) when the morphology match was found high. Bundle brunch re-entry (BBR) VT was another differential. An EP study conducted on antiarrhythmic drugs (AAD) induced reproducible but only ill-sustained tachycardia too short to perform any SVT maneuvers during tachycardia. However, critical analysis of the tachycardia electrograms suggested atypical AVNRT as the most likely mechanism. The other differentials were atrial tachycardia (AT) and BBR VT. Manoeuvres during sinus rhythm and ventricular pacing excluded other diagnosis. A single point radiofrequency ablation (RFA) near the SP region cured the arrhythmia. The reason for misclassification of SVT as VT was also sought for. It was found that the shocks were received due to fulfilment of 2/3 criteria (sudden onset and regular tachycardia). Hence, he received therapy despite an appropriate morphology match favouring SVT. This is one of the known limitations of ICDs where regular SVTs (AVNRT/AVRT or AT) may receive inappropriate ICD therapies. After slow pathway modification there was no further recurrence of either SVT or VT; hence, a substrate modification was deferred.

Analysis of ST segment depression in supraventricular tachycardia and its relationship with underlying mechanism.

BACKGROUND: Electrocardiographic diagnosis of causes of supraventricular tachycardia (SVT) is sometimes difficult and application of routine algorithms can lead to misdiagnosis in as many as 37 % of patients. ST segment depression may be useful in diagnosing the nature of SVT. METHODS: We reviewed surface electrocardiogram (ECG) characteristics of 300 patients having SVT with 1:1 AV relationship and correlated findings with electrophysiology study (EPS) findings. Final diagnosis of AVNRT (Atrioventricular nodal reentrant tachycardia), Orthodromic AVRT (atrioventricular reentrant tachycardia) and atrial tachycardia (AT) was correlated with ECG parameters like heart rate, ST segment depressions and QRS morphology. RESULTS: Out of 300 patients, majority patients included in study, were having AVNRT or AVRT. ST depression predicted AVRT if the ST depression was ≥ 2 mm (overall sensitivity of 38.3 % and specificity of 93.8 % to predict AVRT) and was downsloping in morphology (sensitivity of 36.9 % and specificity of 94.7 % to predict AVRT). At heart rates ≥214 beats per minute (bpm) as measured by 7 small squares of ECG at 25 mm/s, downsloping ST depression ≥2 mm had a sensitivity 37.9 % of and specificity of 89.2 % to predict AVRT. At heart rate <214 bpm, downsloping ST depression ≥2 mm had sensitivity of 37.2 % and specificity of 96.5 % to predict AVRT. Downsloping ST depression of ≥2 mm helps to differentiate AVNRT from AVRT. CONCLUSION: A downsloping ST segment depression ≥2 mm predicted SVT being an AVRT and can be used as a useful criteria in diagnosing the tachycardia.

Optimal method for ablation of atypical AVNRT.

BACKGROUND: Considering that ablation of atypical AVNRT may be unsuccessful after ablation at the right posterior septum, in this study, we aimed to present an optimal method for ablation of atypical AVNRT. Also, we evaluated the efficacy of this technique for preventing recurrences. METHODS: This is a prospective, double-center study. It was conducted on 62 patients with atypical AVNRT referred for radiofrequency ablation. The patients were randomly divided into two groups before ablation: 1-Group A (n = 30): treated with conventional ablation at the anatomic area of the slow pathway; 2-Group B (n = 32): ablation was done 2 mm higher in the septum during fluoroscopy. RESULTS: The mean age of patients in groups A and B were 54 ± 11.7 and 55 ± 12.2, respectively (P = 0.43). In group A, ablation was successful in 24 (80%) patients following right-sided slow pathway ablation, and the remaining patients required further treatment with either a left-side approach (N = 4, 13.3%) or ablation of additional regions (N = 2, 6.7%). In group B, ablation was successful in all patients. After a 48-month follow-up, recurrence of symptomatic atypical AVNRT was detected in 4 (13.3%) patients of group A and none of group B patients (p < 0.001). CONCLUSION: In patients with atypical AVNRT, ablation 2 mm above the conventional area is more promising regarding success rate and recurrence of the arrhythmia.

Ripple mapping: A precise tool for atrioventricular nodal reentrant tachycardia ablation.

INTRODUCTION: Ablation for atrioventricular nodal reentrant tachycardia (AVNRT) classically utilizes evaluation of signal morphology within the anatomic region of the slow pathway (SP), which involves subjectivity. Ripple mapping (RM; CARTO-3© Biosense Webster Inc) displays each electrogram at its three-dimensional coordinate as a bar changing in length according to its voltage-time relationship. This allows prolonged, low-amplitude signals to be displayed in their entirety, helping identify propagation in low-voltage areas. We set out to evaluate the ability of RM to locate the anatomic site of the SP and assess its use in guiding ablation for AVNRT. METHODS: Patients ≤18 years with AVNRT in the EP laboratory between 2017 and 2021 were evaluated. RM was performed to define region of SP conduction in patients from 2019 to 2021, whereas standard electro-anatomical mapping was used from 2017 to 2019. All ablations were performed using cryotherapy. Demographics, outcomes, and analysis of variance in number of test lesions until success was compared between groups. RESULTS: A total of 115 patients underwent AVRNT ablation during the study; 46 patients were in the RM group and 69 were in the control group. There were no demographic differences between groups. All procedures, in both groups, were acutely successful. In RM group, 89% of first successful lesions were within 4 mm of the predicted site. There was significantly reduced variability in number of test lesions until success in the RM group (p = .01). CONCLUSION: RM is a novel technique that can help identify SP location, allowing for successful ablation of AVNRT with decreased variability.

A case series of very slow atrioventricular nodal reentrant tachycardia resembling junctional tachycardia.

INTRODUCTION: The surface electrocardiography of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular-atrial (RP) activation with pseudo R' in V1 and typical heart rates ranging from 150 to 220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min. METHODS: A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; (1) evidence of dual atrioventricular nodal conduction, (2) tachycardia initiation by atrial drive train with atrial-His-atrial response, (3) short septal ventriculoatrial time, and (4) ventricular-atrial-ventricular (V-A-V) response to ventricular overdrive (VOD) pacing with corrected post pacing interval-tachycardia cycle length (cPPI-TCL) > 110 ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing. RESULTS: We found 11 patients (age 20-78 years old, six female) who met the above-mentioned criteria. The TCL ranged from 560 to 782 ms. Except for one patient showing tachycardia termination, all patients demonstrated a V-A-V response and cPPI-TCL over 110 ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients. CONCLUSIONS: This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Late pacemaker implantation after atrioventricular nodal reentrant tachycardia ablation: A systematic review and meta-analysis.

INTRODUCTION: Catheter ablation (CA) of atrioventricular nodal reentrant tachycardia (AVNRT) is associated with late pacemakers for AV block (AVB). We performed a systematic review and meta-analysis of the pooled incidence of late pacemakers for AVB after CA of AVNRT. METHODS AND RESULTS: Relevant studies were identified from four electronic databases (PubMed, EMBASE, Scopus, and Cochrane Trial Register) from inception to 2022. A random effects model was used to calculate the odds of late pacemakers in CA of AVNRT compared to atrioventricular reentrant tachycardia (AVRT). Of 533 articles screened, 13 were included in systematic review. CA for AVNRT was performed in 16 471 patients (mean age 54 ± 17 years, 63% females), of which 68 (0.4%) underwent pacemaker implantation for late AVB. Meta-analysis was performed in 5 of the 13 studies (mean follow-up duration 7 ± 4 years). Patients who underwent CA of AVNRT were older (58 ± 17 vs. 52 ± 20 years, p < .001), and more likely female (60% vs. 41%, p < .001) than AVRT. Pooled estimates of late pacemakers for AVB were higher in CA of AVNRT than AVRT (0.5% vs. 0.2%, p = .006), with CA in AVNRT associated with almost twofold increased odds of late pacemakers indicated for AVB (odds ratio: 1.94, 95% confidence interval: 1.08-3.47, p = .027) compared to AVRT. CONCLUSION: AVNRT ablation is safe but associated with a low but definitely increased risk of requiring pacing in the later years due to AVB. This association is confirmed by pooling over 16 000 AVNRT patients receiving clinically indicated ablation and is helpful in providing informed consent for prospective patients undergoing ablation for AVNRT.

Inducibility of atrioventricular nodal reentrant tachycardia and ectopic atrial tachycardia in children under general anesthesia.

BACKGROUND: In children, invasive electrophysiological studies (EPS) and radiofrequency catheter ablations (RFA) of supraventricular tachycardia (SVT) are often performed under general anesthesia. Atrioventricular nodal reentrant tachycardia (AVNRT) and ectopic atrial tachycardia (EAT) must be inducible during EPS as reliable diagnosis and subsequent therapy are not possible in sinus rhythm. This study aims to assess the problem of noninducible AVNRT and EAT under general anesthesia. METHODS AND RESULTS: Anesthesia protocols of 166 patients undergoing EPS were retrospectively analyzed. 122 AVNRT patients were compared to 22 whose tachycardia was not inducible but probably due to an AVNRT mechanism. Another 16 patients with inducible EAT were compared to 6 whose EAT appeared on surface ECG but not during EPS. Demographic characteristics were similar among all groups. Inducibility did not differ (p = .42) between AVNRT patients with inhalational anesthesia (sevoflurane and/or nitrous oxide) and patients with intravenous anesthesia (propofol with/without remifentanil). The EAT group exhibited lower inducibility under intravenous anesthesia (64%) than under inhalational (88%), however without significance (p = .35). CONCLUSION: Tachycardia induction succeeds with similar frequency under both inhalational and intravenous general anesthesia in children with AVNRT. In children with EAT, inhalational anesthesia is associated with a trend towards better inducibility.

Case report: Wide-complex tachycardia one week post-CRT-D implantation in a patient with pre-existing left bundle branch block.

A 37-year-old female with dilated cardiomyopathy, whose baseline ECG showed sinus rhythm with left bundle branch block pattern, received a cardiac resynchronization therapy defibrillator (CRTD). One week post-implantation, she presented to the emergency department with palpitations, diaphoresis and chest discomfort. ECG showed a wide-complex tachycardia (WCT) episode, which spontaneously converted to sinus rhythm, and was later diagnosed as typical slow-fast atrioventricular nodal re-entrant tachycardia. This report outlines the differential diagnoses for WCT and the reasoning behind the eventual diagnosis, taking into consideration the device interrogation findings and results of the electrophysiology study.

Empiric Slow Pathway Cryoablation in Symptomatic Children Without Documented Supraventricular Tachycardia.

In symptomatic children without documented supraventricular tachycardia (SVT) and non-inducible atrioventricular nodal reentry tachycardia (AVNRT) the benefit of empiric slow pathway (SP) ablation is unknown. We evaluated 62 symptomatic patients without documented SVT that underwent electrophysiology study (EPS). The purpose of this study was to determine if symptoms improved after empiric SP ablation in children without documented SVT and without inducible AVNRT. Sixty-two symptomatic patients without previously documented SVT underwent EPS; 31 (50%) had inducible AVNRT and underwent SP ablation, 20 (32%) were non-inducible and underwent empiric SP ablation, 11 (18%) were non-inducible and had no ablation. After a mean follow-up of 23 ± 18 months there was no significant difference in freedom from symptoms within the non-inducible cohort regardless of whether empiric SP ablation was performed (p = 0.135). There was a significant improvement in symptoms at follow-up after SP ablation when comparing inducible and non-inducible patients (p = 0.020). During follow-up no patients had documented SVT. Symptomatic children without documented SVT do not benefit from empiric SP ablation when AVNRT cannot be induced.

Change in VA interval by a single atrial premature depolarization - What is the mechanism?

A long VA tachycardia during a typical atrioventricular nodal reentrant tachycardia (AVNRT) can be a concomitant atypical AVNRT, atrial tachycardia or rarely atrio-ventricular reentrant tachycardia (AVRT). There are reported associations of AVNRT with other tachycardia substrates. Maneuvers are useful for differentiating the mechanism of the second tachycardia. Atrial tachycardia (AT) is one common association. When the AT originates from the lower triangle of Koch/near coronary sinus ostium, it can mimic slow-slow/fast-slow AVNRT. We encountered an interesting case where a longer VA tachycardia got reproducibly induced when a critically timed atrial premature depolarisation was delivered on typical AVNRT. It was proved to be an AT. A slow pathway modification in the lower TOK was successful to eliminate both the tachycardia substrate.

Gender associated disparities in atrioventricular nodal reentrant tachycardia: A review article.

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common sustained supraventricular arrhythmias. An understanding of gender-related differences in AVNRT epidemiology, diagnosis, treatment, outcome, and complications can help guide a more effective diagnosis and treatment of the condition. The study aimed to perform a review of the available literature regarding all aspects of gender-related differences of AVNRT. We focused on all aspects of gender-related differences regarding AVNRT between men and women. A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct. Many investigations have demonstrated that the prevalence of AVNRT exhibited a twofold women-to-men predominance. The potential mechanism behind this difference due to sex hormones and autonomic tone. Despite being more common in women, there is a delay in offering and performing the first-line therapy (catheter ablation) compared to men. There were no significant gender-related discrepancies in patients who underwent ablation therapy for AVNRT, regarding the acute success rate of the procedure, long-term success rate, and recurrence of AVNRT. AVNRT is more common in women due to physiological factors such as sex hormones and autonomic tone. Catheter ablation is equally safe and efficacious in men and women; however, the time between the onset of symptoms and ablation is significantly prolonged in women. It is important for the medical community to be aware of this discrepancy and to strive to eliminate such disparities that are not related to patients' choices.

Environmental Fe, Ti, Al, Cu, Hg, Bi, and Si Nanoparticles in the Atrioventricular Conduction Axis and the Associated Ultrastructural Damage in Young Urbanites: Cardiac Arrhythmias Caused by Anthropogenic, Industrial, E-Waste, and Indoor Nanoparticles.

Air pollution exposure is a risk factor for arrhythmia. The atrioventricular (AV) conduction axis is key for the passage of electrical signals to ventricles. We investigated whether environmental nanoparticles (NPs) reach the AV axis and whether they are associated with ultrastructural cell damage. Here, we demonstrate the detection of the shape, size, and composition of NPs by transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometry (EDX) in 10 subjects from Metropolitan Mexico City (MMC) with a mean age of 25.3 ± 5.9 and a 71-year-old subject without cardiac pathology. We found that in every case, Fe, Ti, Al, Hg, Cu, Bi, and/or Si spherical or acicular NPs with a mean size of 36 ± 17 nm were present in the AV axis in situ, freely and as conglomerates, within the mitochondria, sarcomeres, lysosomes, lipofuscin, and/or intercalated disks and gap junctions of Purkinje and transitional cells, telocytes, macrophages, endothelium, and adjacent atrial and ventricular fibers. Erythrocytes were found to transfer NPs to the endothelium. Purkinje fibers with increased lysosomal activity and totally disordered myofilaments and fragmented Z-disks exhibited NP conglomerates in association with gap junctions and intercalated disks. AV conduction axis pathology caused by environmental NPs is a plausible and modifiable risk factor for understanding common arrhythmias and reentrant tachycardia. Anthropogenic, industrial, e-waste, and indoor NPs reach pacemaker regions, thereby increasing potential mechanisms that disrupt the electrical impulse pathways of the heart. The cardiotoxic, oxidative, and abnormal electric performance effects of NPs in pacemaker locations warrant extensive research. Cardiac arrhythmias associated with nanoparticle effects could be preventable.

Post-cardiac injury syndrome triggered by radiofrequency ablation for AVNRT.

BACKGROUND: Post-cardiac injury syndrome (PCIS) is an inflammatory condition following myocardial or pericardial damage. In response to catheter ablation, PCIS most frequently occurs after extensive radiofrequency (RF) ablation of large areas of atrial myocardium. Minor myocardial injury from right septal slow pathway ablation for atrioventricular nodal reentrant tachycardia (AVNRT) is not an established cause of the syndrome. CASE PRESENTATION: A 62-year-old women with a 6-year history of symptomatic narrow-complex tachycardia was referred to perform an electrophysiological study. During the procedure AVNRT was recorded and a total of two RF burns were applied to the region between the coronary sinus and the tricuspid annulus. Pericardial effusion was routinely ruled out by focused cardiac ultrasound. In the following days, the patient developed fever, elevated inflammatory and cardiac markers, new-onset pericardial effusion, characteristic ECG changes, and complained of pleuritic chest pain. An extensive workup for infectious, metabolic, rheumatologic, neoplastic, and toxic causes of pericarditis and myocarditis was unremarkable. Cardiac magnetic resonance imaging showed no signs of ischemia, infiltrative disease or structural abnormalities. The patient was diagnosed with PCIS and initiated on aspirin and low-dose colchicine. At a 1-month follow-up visit the patient was free of symptoms but still had a small pericardial effusion. After three  months of treatment the pericardial effusion had resolved completely. CONCLUSIONS: Inflammatory pericardial reactions can occur after minor myocardial damage from RF ablation without involvement of structures in close proximity to the pericardium.

The importance of sustained junctional tachycardia following cessation of radiofrequency current delivery in slow pathway ablation.

BACKGROUND: Apart from junctional rhythms during slow pathway ablation, there is limited knowledge about the junctional tachycardia persisting following ablation cessation. This study is conducted to determine the characteristics and significance of this rare arrhythmia. METHODS AND RESULTS: This study was done on 487 patients with AVNRT undergoing the radiofrequency ablation. The RF delivery-induced Supraventricular Tachycardia, persisting for a few minutes following the termination of ablation (post-ablation SVT) was investigated in this research. Atrial Overdrive Pacing (AOP) was applied to the post-ablation SVT to distinguish AVNRT from Junctional Tachycardia(JT). A total of 2337 RF-current deliveries were applied, and post-ablation SVT was observed in 81 of them. According to the electrophysiological studies, five of them (in five separate cases) were definitely diagnosed as JT. The overall incidence of post-ablation JT was about 1% of all patients. In these cases, RF energy was applied to the posteroseptal region and roof of the proximal coronary sinus. The mean Cycle Length (CL) of JTs was equal to 446 ±67ms. Following post- ablation JT termination, four cases met endpoints of successful ablation, demonstrating a positive predictive value of 80%. Atrioventricular (AV) block did not occur in any of the cases and reappearance of JT was not observed during procedure or mean follow-up period of 19.8 ± 8.4 months. CONCLUSIONS: Post-ablation JT is probably a transient Ischemia-induced arrhythmia that does not require further ablation. Thus, it is recommended to differentiate between the AVNRT and JT in post-ablation arrhythmias to avoid unnecessary RF application.

Persistence of Palpitations After Slow Pathway Modification for AVNRT in Young People.

Symptoms are the most common indication for ablation in children with atrioventricular nodal reentrant tachycardia (AVNRT). After the procedure, patients may continue to report palpitations. The objective of this study was to quantify the risk and duration of palpitations after pediatric slow pathway modification as well as demographic and technical associations. This was a retrospective review of consecutive patients at a pediatric center who underwent slow pathway modification for AVNRT from 2012 to 2018. Patients with a prior ablation attempt or congenital heart disease were excluded. Palpitations were documented in 35% of patients after ablation. Neither post-ablation echo beats nor other evidence of residual dual AV nodal physiology were associated with a higher risk of post-ablation palpitations. Of the 35 patients with post-ablation palpitations, the median time to resolution of palpitations was 48 months. Acute procedural success was achieved in all 100 cases. There were two recurrences of AVNRT during long-term follow-up and one instance of ectopic atrial tachycardia (3% SVT recurrence). Palpitations after AVNRT ablation occurred in approximately one-third of cases, despite a low recurrence of true arrhythmia. Prior to ablation, patients and families should be counseled that post-ablation palpitations are common and AVNRT recurrence is rare.

Left sided ablation for Atrioventricular Nodal Re-entrant Tachycardia: Frequency, Characteristics and Outcomes.

BACKGROUND: Left-sided ablation, targeting left inferior AV nodal extensions, is thought to be necessary for success in a small proportion of atrioventricular nodal re-entrant tachycardia (AVNRT) ablations; however Indian data are scarce in this regard. METHODS: Consecutive cases of AVNRT undergoing slow pathway ablation in a single centre over an 18-month period were retrospectively analyzed. Left-sided ablation at the posteroseptal mitral annulus was performed if right-sided ablation failed to abolish AVNRT. RESULTS: From January 2017 to June 2018, out of 215 consecutive supraventricular tachycardia (SVT) cases, 154 (71.6%) were AVNRT (47.1 ± 13.1 years, 46.1% male). Trans-septal ablation was required in 5 (3.2%) cases (mean age 48.8 ± 9.4 years; 4 female, 1 male); all with typical (slow-fast) form of AVNRT. Compared with cases needing only right-sided ablation, radiofrequency time (50.8 ± 16.9 vs. 9.9 ± 8.5 min; p = 0.005) and procedure time (166.0 ± 35.0 vs 79.6 ± 35.9 min; p = 0.004) were significantly longer for trans-septal cases, while baseline intervals and tachycardia cycle length were not significantly different. Junctional ectopy was seen in only 2 of the 5 cases during left-sided ablation, but acute success (non-inducibility) was obtained in 3 cases. There were no instances of AV block. Over mean follow-up of 12.2 ± 4.0 months, clinical recurrence of AVNRT occurred in one case, while others remained arrhythmia-free without medication. CONCLUSION: Left-sided ablation was required in a small proportion of AVNRT ablations. Trans-septal approach targeting the posteroseptal mitral annulus was safe and yielded good mid-term clinical success.

Evaluation of cardiac functions after catheter ablation of atrioventricular nodal reentrant tachycardia

Background/aim: Radiofrequency catheter ablation (RFA) is the most effective method of supraventricular tachycardia therapy. Recurrent supraventricular tachycardia causes systolic dysfunction and dilated cardiomyopathy. The aim of this study was to evaluate the long-term alterations of atrial and ventricular functions after RFAof typical atrioventricular nodal reentrant tachycardia (AVNRT). Materials and methods: This cross-sectional study included 55 consecutive patients with symptomatic drug-resistant AVNRT who had had an invasive electrophysiology study and RFA. Speckle-tracking­based echocardiographic assessment was performed shortly before and 1 year after the operation. Left ventricle (LV) and right ventricle (RV) peak systolic strain (PSS) and atrial strain measurements were performed. Results: RFA successfully eliminatedtachyarrhythmia in all patients. LV apical 4-chamber PSS ­20.8% (­24.7 to ­16.0) vs. ­22.8% (­26.6 to ­17.0, P < 0.001), LV apical 2-chamber PSS ­21.5% (­26.8 to ­10.1) vs. ­22.0% (­27.8 to ­13.7, P < 0.001), LV global PSS ­20.4% (­26.4 to ­14.4) vs. ­23.0% (­27.1 to ­2.3, P < 0.001), RV global PSS ­26.0% (­30.0 to ­18.0) vs. ­26.5% (­32.1 to ­19.7, P < 0.001), and peak left atrial longitudinal strain 41.0% (19.0­71.8) vs. 54.0% (25.6­82.0, P < 0.001) were significantly improved 1 year after RFA. Conclusion: RFA of AVNRT not only provides relief of palpitations but also improves cardiac functions.