Impact of preoperative electrophysiological intervention on occurrence of peri/postoperative supraventricular tachycardia following Fontan surgery.

BACKGROUND: Little is known about the effects of preoperative electrophysiological study (EPS) and catheter ablation (CA) in Fontan surgery candidates with supraventricular tachycardia (SVT). OBJECTIVE: The purpose of this study was to investigate the clinical impact of EPS-guided intervention in Fontan surgery candidates with preceding SVT events. METHODS: A total of 109 consecutive patients with a history of SVT before Fontan surgery were divided into 3 groups: 44 in whom EPS with CA was attempted (CA group); 21 in whom EPS without CA was attempted (EPS group); and 44 in whom EPS was not performed (N group). The incidence and diagnosis of SVT, acute success rate of CA, and risk factors of peri/postoperative SVT were retrospectively investigated. RESULTS: The total incidence of SVT within 1 year after Fontan surgery was 34% (n = 37), with 91% of cases occurring within 1 month. Among the 71 SVT incidences diagnosed with EPS, 31 were atrioventricular reentrant tachycardias (AVRTs) involving twin atrioventricular nodes, 12 were atrioventricular nodal reentrant tachycardias, 12 were atrial tachycardias, 7 were orthodromic AVRTs via the accessory pathway, 7 were atrial flutters, and 2 were junctional tachycardias. The acute success rate of CA was 91% (48/53). The rate of peri/postoperative atrioventricular reciprocating SVT was significantly lower in the CA group than in the N or EPS group (11% vs 43% or 43%; P <.05). No/unsuccessful CA significantly increased the risk of peri/postoperative SVT in multivariate analysis (odds ratio 4.43; 95% confidence interval 1.69-11.59). CONCLUSION: Preoperative CA reduces peri/postoperative SVT occurrence in Fontan surgery candidates at high risk for SVT.

Electrophysiological features and radiofrequency catheter ablation of accessory pathways associated with atrioventricular discordance.

INTRODUCTION: Although a high prevalence of the presence of an accessory pathway (AP) associated with atrioventricular (AV) discordance has been reported, a case series of its characteristics and the results of catheter ablation (CA) have not been sufficiently documented. METHODS AND RESULTS: We retrospectively examined 11 consecutive patients with atrioventricular discordance who underwent CA for atrioventricular reciprocating tachycardia (AVRT) via an AP and planned cardiac surgery after CA. Orthodromic AVRTs were induced in 10 patients via AP, but no antidromic/duodromic AVRT was induced in any of the cases. A total of 13 APs were identified, and all of them were located around the anatomical tricuspid valve (TV) annulus, including two Ebsteinoid valves. The APs were predominantly located posteriorly, posterolaterally, and posteroseptally on the TV in nine patients (82%). Two patients (18%) had multiple APs or a single broad AP. Four (36%) and three (27%) patients showed twin AVNs and other supraventricular tachycardias (SVTs) except AVRT via the AP. Ten patients (91%) had acute successful CA in the first session, except for one patient with multiple APs who required the third session to eliminate all APs before the planned Fontan surgery. There were no major complications associated with CA. Seven of eight patients who underwent cardiac surgery after CA did not experience peri-/postoperative SVT. CONCLUSION: APs in patients with AV discordance are usually associated with the anatomical TV annulus. CA of an AP in AV discordance is highly effective and recommended to reduce the risk of SVT. The coexistence of twin AVNs and other SVTs should be considered during CA of an AP in AV discordance.

Comparison Between Contact Force Monitoring and Unipolar Signal Modification as a Guide for Catheter Ablation of Atrial Fibrillation: Prospective Multi-Center Randomized Study.

BACKGROUND: Both contact force monitoring (CFM) and unipolar signal modification (USM) are guides for ablation, which improve the efficacy of pulmonary vein isolation of atrial fibrillation. We sought to compare the outcomes of atrial fibrillation ablation guided by CFM or USM. METHODS: A total of 136 patients with paroxysmal atrial fibrillation underwent a circumferential pulmonary vein isolation using CF sensing ablation catheters and were randomly assigned to undergo catheter ablation guided by either CFM (CFM-guided group: n=70) or USM (USM-guided group: n=66). In the USM-guided group, each radiofrequency application lasted until the development of completely positive unipolar electrograms. In the CFM-guided group, a CF of 20 g (range, 10-30 g) and minimum force-time integral of 400 g were the targets for each radiofrequency application. The primary end point was freedom from any atrial tachyarrhythmia recurrence without antiarrhythmic drugs at 12-months of follow-up. RESULTS: The cumulative freedom from recurrences at 12-months was 85% in the USM-guided group and 70% in the CFM-guided group (P=0.031). The incidence of time-dependent and ATP-provoked early electrical reconnections between the left atrium and PVs, procedural time, fluoroscopic time, and average force-time integral, did not significantly differ between the 2 groups. The radiofrequency time for the pulmonary vein isolation was shorter in the USM-guided group than CFM-guided group but was not statistically significant (P=0.077). CONCLUSIONS: USM was superior to CFM as an end point for radiofrequency energy deliveries during the pulmonary vein isolation in patients with paroxysmal atrial fibrillation in terms of the 12-month recurrence-free rate. CLINICAL TRIAL REGISTRATION: URL: https://www.umin.ac.jp/ctr/index.htm. Unique identifier: UMIN000021127.

Is It Necessary to Achieve a Complete Box Isolation in the Case of Frequent Esophageal Temperature Rises? Feasibility of Shifting to a Partial Box Isolation Strategy for Patients With Non-Paroxysmal Atrial Fibrillation.

INTRODUCTION: There are some cases with frequent luminal esophageal temperature (LET) rises despite titrating the radiofrequency energy while creating a linear lesion for the Box isolation of atrial fibrillation (AF). Little is known about the feasibility of redesigning the ablation lines for a modified Box isolation strategy to prevent fatal esophageal injury in those cases. METHODS AND RESULTS: Two hundred and seventeen patients who underwent a Box isolation of non-paroxysmal AF were evaluated. We divided them into 2 groups, patients in whom a box lesion set of the entire posterior left atrium had been achieved (complete Box isolation [CBI]; n = 157) and those in whom 2 additional peri-esophageal vertical lines were created at both the right and left ends of the esophagus, and those areas were left with an incomplete isolation when frequent rapid LET rises above 39.0 °C were observed while creating the floor line (partial Box isolation [PBI]; n = 60). During 20.1 ± 13.9 months of follow-up, the arrhythmia-free rates were 54.1% in the CBI group versus 48.3% in the PBI group (P = 0.62). In the second session, a complete Box isolation was highly achieved even in the PBI group (94.3% vs. 83.3%, respectively; P = 0.17) and after 2 procedures, the arrhythmia-free rates increased to 75.2% vs. 68.3%, respectively (P = 0.34). There was no symptomatic esophageal injury in the PBI group. CONCLUSION: In the case of frequent LET rises while creating the linear lesions for the Box isolation strategy for non-paroxysmal AF, shifting to the PBI strategy was feasible.

Localized reentrant tachycardia in the aorta contiguity region mimicking perimitral atrial flutter in the context of atrial fibrillation ablation.

We describe a case with a focal atrial tachycardia (AT) masquerading as perimitral atrial flutter revealed after circumferential pulmonary vein antral isolation for atrial fibrillation. It was successfully terminated and became noninducible by a point ablation on the left atrial anterior wall (LAAW) near the mitral annulus in contact with the aortic root and on the left superior pulmonary vein-left atrial appendage ridge, without any linear ablation, using electroanatomical mapping and conventional precise mapping with a maximum amplified gain within the low-voltage area. The AT revealed in our case was an LAAW-aorta contiguity area-related AT.

Successful catheter ablation and documentation of the activation and propagation pattern during a left atrial focal tachycardia in a patient with cor triatriatum sinister.

We report a case of an atrial tachycardia (AT) originating from the left atrium (LA) associated with cor triatriatum sinister. Electroanatomical mapping of the 2 subdivided chambers of the LA during the AT revealed a centrifugal activation pattern from the posterior wall of the accessory chamber near the left superior pulmonary vein. The propagation map on the CARTO system revealed that the AT wave front spread centrifugally over the "accessory chamber," turned around the edge of the membrane subdividing the LA, and then spread over the "main chamber." A single radiofrequency application successfully abolished the AT.

Bi-focal atrial tachycardia mimicking atrial fibrillation: fusion and interference between two distinct tachycardias.

Irregular tachycardias mimicking atrial fibrillation (AF) have previously been described. We report a case of a 60-year-old man with an antiarrhythmic drug-resistant atrial tachycardia (AT) mimicking AF. The tachycardia consisted of two distinct ATs with interference of one repetitive AT with another sustained AT. Radiofrequency (RF) ablation of two distinct right atrial foci eliminated the irregular tachycardia. Although catheter-based pulmonary vein isolation has become a popular therapeutic approach for patients with symptomatic AF, careful evaluation of the intracardiac recordings in the patients undergoing RF ablation for AF is important.

Anatomical structure of the isthmus between the inferior vena cava and tricuspid annulus investigated with a three-dimensional electroanatomical mapping system.

We studied the anatomical structure of the isthmus between the inferior vena cava and tricuspid annulus in humans with a three-dimensional electroanatomical mapping system (CARTO, Biosense, Haifa, Israel). Fifteen patients with atrial flutter were studied. Thirteen patients had underlying heart disease. We investigated the anatomical structure of the isthmus with cross sections made from the three-dimensional right atrial map. The cross sections of the isthmus showed a concave shape in 7 patients (47%: group A), convex shape in 2 (13%: group B), and complex shape in 6 (40%: group C). The distance between the IVC and TA was 34+/-17 mm (group A), 25+/-2 mm (group B), 34+/-16 mm (group C), and 32+/-15 mm (Total), respectively. The distance between the top and bottom was 6+/-5 mm (group A), 3 mm (group B), 6+/-3 mm (group C), and 6+/-4 mm (total), respectively. Seven of 15 patients exhibited an uneven surface of more than 5 mm in depth and 4 of 15 patients had one of more than 10 mm. The anatomical structure of the isthmus varies. To carry out precise catheter ablation, these variations should be taken into consideration to ensure an effective procedure.