Identification of a critical isthmus in complex macroreentrant atrial tachycardia using Ripple mapping in a patient with surgically repaired Ebstein's anomaly.

Ripple mapping is a novel, three-dimensional, electroanatomic mapping tool that displays each electrogram at its corresponding 3-dimensional coordinate as a dynamic moving bar, which changes in length according to the electrogram voltage-time relationship. We present the case of a 43-year-old male patient with surgically repaired Ebstein's anomaly who previously underwent two unsuccessful ablation procedures for right atrial flutter (cavotricuspid isthmus and intercaval lines). Ripple mapping was decisive, enabling the arrhythmia mechanism to be appropriately recognized, and a distinction to be made between critical areas of the circuit and delayed activated bystander regions.

Mechanisms of Intra-Atrial Re-Entrant Tachycardias in Congenital Heart Disease: Types and Predictors.

Intra-atrial re-entrant tachycardia (IART) is a severe complication in patients with congenital heart disease (CHD). Cavotricuspid isthmus (CTI)-related IART is the most frequent mechanism. However, due to fibrosis and surgical scars, non-CTI-related IART is frequent. The main objective of this study was to describe the types of IART, circuit locations, and to analyze predictors of CTI versus non-CTI-related IART. This is an observational study that includes all consecutive patients with CHD who underwent a first IART ablation in a single referral tertiary hospital from January 2009 to December 2015 (94 patients; 39.4% women; age: 36.55 ± 14.9 years, 40.4% with highly complex cardiac disease). During the study, 114 IARTs were ablated (1.21 ± 0.41 IARTs per patient). CTI-related IART was the only arrhythmia in 51% (n = 48) of patients; non-CTI-related IART was the only mechanism in 27.7% (n = 26), and 21.3% of patients (n = 20) presented the two types of IART. Severe dilation of the systemic ventricle, absence of severe dilation of the venous atrium, highly complex cardiac defects, and nontypical electrocardiography (ECG) were related to non-CTI-related IART in univariate analysis. In multivariate analysis, nontypical ECG (odds ratio 3.64; 1.01 to 4.9; p = 0.049) and grade III CHD complexity (odds ratio 9.43; 1.44 to 11.7; p = 0.001) were predictors of non-CTI-related IART. In conclusion, in our population with a high proportion of complex CHD, CTI-related IART was the most frequent mechanism, although non-CTI-related IART was present in 49% (alone or with concomitant CTI-related IART). High-grade CHD complexity and nontypical ECG were strongly related to non-CTI IART.

A Simple Method to Differentiate Atrioventricular Node Reentrant Tachycardia from Orthodromic Reciprocating Tachycardia.

Discrimination between atrioventricular node reentry tachycardia (AVNRT) and orthodromic reciprocating tachycardia (ORT) during an electrophysiological study is sometimes challenging. This study aimed to investigate if the difference in the local VA (ventricle-atrium) interval during ventricular entrainment pacing and during tachycardia (DVA, defined as the shortest local VA interval of coronary sinus [CS] during entrainment minus the shortest local VA interval of CS during tachycardia) was different in patients with AVNRT and patients with ORT.Diagnoses of AVNRT or ORT through a concealed accessory pathway (AP) were made according to conventional electrophysiological criteria and ablation results. Entrainment by right ventricular (RV) pacing was performed in each patient before ablation and patients with successful entrainment were included in the study. The DVA was compared between patients with AVNRT and patients with ORT. The DVA in patients with AVNRT was significantly longer than that in patients with ORT (120 ± 20 versus 5.7 ± 9; P < 0.001). In each patient with AVNRT of slow-fast type, fast-slow type, and slow-slow type, the DVA was more than 48 ms. In each patient with ORT using a left free wall accessory pathway (AP), right free wall AP, and septal AP, the DVA was less than 20 ms.DVA was found to be a rapid, useful test in distinguishing patients with AVNRT from those with ORT.

Palpitations in a 72-year-old woman.

CLINICAL INTRODUCTION: A 72-year-old woman presented with an 8-year history of palpitations occurring every few weeks. They were sudden in onset, were associated with dizziness and could last for up to 2 hours. She was prescribed bisoprolol which reduced the frequency of events but did not abolish them. Baseline ECG and echocardiography were normal. She was referred for electrophysiological study. Despite initial difficulties, diagnostic catheters were placed in the right ventricular (RV) apex and in the coronary sinus (CS) via the right internal jugular vein and superior vena cava (SVC) (figure 1A). A narrow complex tachycardia was easily induced, and ablation was then delivered during tachycardia with the ablation catheter positioned as shown in (figure 1A). This terminated tachycardia 4 s after onset of energy delivery and on follow-up she has remained asymptomatic. She later underwent a CT scan (figure 1B,C; online supplementary video).DC1SP110.1136/heartjnl-2017-311734.supp1Supplementary file 1 heartjnl;103/19/1554/F1F1F1Figure 1(A) Fluoroscopy of catheter placement. (B) Sagittal contrast-enhanced CT image. (C) Axial contrast-enhanced CT. QUESTION: What anatomical abnormality caused difficulty in catheter placement during the procedure?Azygous continuation of the inferior vena cava (IVC)Giant Eustachian valveDextrocardiaRenal tumour compressing IVC.

Clinical and electrophysiological characteristics of typical atrioventricular nodal reentrant tachycardia in the elderly - changing of slow pathway location with aging.

BACKGROUND: The aim of this study was to retrospectively evaluate the clinical and electrophysiological characteristics of elderly patients with typical atrioventricular nodal reentrant tachycardia (AVNRT), and to assess the acute safety and efficacy of slow-pathway radiofrequency (RF) ablation in this specific group of patients. METHODS AND RESULTS: The present study retrospectively included a total of 1,290 patients receiving successful slow-pathway RF ablation for typical slow-fast AVNRT. Patients were divided into 2 groups: group I included 1,148 patients aged <65 years and group II included 142 patients aged >65 years. The required total procedure duration and total fluoroscopy exposure time were significantly higher in group II vs. group I (P=0.005 and P=0.0001, respectively). The number of RF pulses needed for a successful procedural end-point was significantly higher in group II than in group I (4.4 vs. 7.2, P=0.005). While the ratio of the anterior location near to the His-bundle region was significantly higher in group II, the ratio of posterior and midseptal locations were significantly higher in group I (P=0.0001). The overall procedure success rates were similar. There was no significant difference between the 2 groups in respect of the complications rates. CONCLUSIONS: This experience demonstrates that RF catheter ablation, targeting the slow pathway, could be considered as first-line therapy for typical AVNRT patients older than 65 years as well as younger patients, as it is very safe and effective in the acute period of treatment.

Spontaneous left atrial reentry tachycardias : radiofrequency ablation and outcome.

AIMS: Spontaneous left atrial reentry tachycardias (LART) in patients without previous cardiac surgical or catheter ablation are rare. Several therapeutic concepts of catheter ablation have been suggested: linear lesions (LL), circumferential pulmonary vein isolation (PVI), and both (LL + PVI). METHODS AND RESULTS: In all, 28 consecutive symptomatic patients with 51 LARTs presented to our institution for catheter ablation. Electroanatomical mapping was performed on 25 patients. Three patients were ablated conventionally during LART; 25 patients (89.3 %) had extensive low-voltage areas in the left atrium (atrial myopathy). One of the following ablation strategies was applied: first, LL (n = 8), second, PVI + LL (n = 11), and third PVI alone (n = 9). Fourteen patients (50 %) had a recurrent arrhythmia during a mean follow-up of 12.2 ± 11.1 months. Six patients presented with a recurrent LART (21.4 %), 4 with LART and atrial fibrillation (Afib) (14.3 %), and 4 with Afib (14.3 %). The recurrence rate of any arrhythmia (LART and Afib) was 37.5 % in the LL group, 44.4 % in the PVI group, and 63.6 % in the PVI + LL group (ns); the recurrence rate of LARTs was 12.5 % in the LL group, 22.2 % in the PVI group, and 63.6 % in the PVI + LL group (p < 0.05). CONCLUSION: Atrial tachyarrhythmia recurrence after ablation of spontaneous LART in mid-term is considerable. Stable LARTs are effectively treated by LL. PVI alone may be an acceptable alternative, especially in patients with unstable LARTs and Afib. However, the risk of recurrent LARTs after a more extensive strategy with PVI and LL is considerable, probably due to proarrhythmic effects of long linear lesions.

Successful ablation of sinus node reentrant tachycardia using remote magnetic navigation system.

Ablation of sinus node reentrant tachycardia (SNRT) may be difficult with risk of sinus node injury by using conventional catheters. We report successful ablation of SNRT by using remote magnetic navigation system (Stereotaxis).

The magnetic navigation system allows avoidance of puncturing a baffle during ablation of a postincisional macroreentrant tachycardia.

An 18-year-old female patient with tricuspid atresia, discordant ventriculo-arterial connections, a total cavo-pulmonary connection, and a Damus-Kaye-Stansel suffered with atrial tachycardia. Use of a magnetically navigated catheter made it possible to create an electro-anatomical map of both atriums using a retrograde approach. It then proved possible to ablate successfully the tachycardia in the left atrium thanks to the unique capabilities of the magnetic navigation system.

[Treatment of arrhythmias associated with congenital heart disease using transcatheter ablation]. / Veleszületett szívbetegséghez társuló ritmuszavarok katéterablatiós kezelése.

UNLABELLED: Rhythm disturbances are common long after surgical repair of congenital heart disease. These arrhythmias caused by the progression of the disease itself, however, a significant proportion is a result of the presence of surgical scar. Although interventional electrophysiology procedures are complex and encounter difficulties, pharmacological therapy is often very disappointing. AIM AND METHODS: In the present study we aimed to describe our experience obtained between 2004 and 2006 in patients undergoing transcatheter ablation long after surgery for congenital heart disease. RESULTS: During this period 26 patients underwent catheter ablation. The procedure was successful in 24 out of the 26 patients (92%). Three patients required redo ablations due to arrhythmia recurrences (11%). There were no major complications related to the intervention. In four patients minor complications occurred (small hematomas). CONCLUSIONS: Our descriptive data indicate that transcatheter ablation for arrhythmias after surgery for congenital heart disease is a effective safe and more importantly curative procedure. It is associated with reasonable success rate, low complication rate, but slightly higher recurrence rate as compared to the classical electrophysiological interventions.

Two atrial reentrant tachycardias originating from the superior vena cava: electrophysiological characteristics and radiofrequency ablation.

A case with two different types of atrial reentrant tachycardia of superior vena cava (SVC) origin is presented. Recent clinical studies have shown that the origin of focal atrial tachycardia typically lies in the venous structures connecting to both atria--the coronary sinus, the superior and inferior vena cava, and the pulmonary vein. These foci have atrial muscle fiber extensions which have electrophysiological characteristics essential to generation of focal ectopic firing. However, little is known about reentrant mechanism of these venous structures. In this report, we present a case of two atrial tachycardias (SVT1 and SVT2) independently originating from the SVC. SVT1 had 430 ms of tachycardia cycle length, and SVT2 had 390 ms of tachycardia cycle length. Both of them showed the character of reentry, and their earliest activations were recorded in the SVC. They were successfully eliminated by focal radiofrequency ablation in the SVC.

Narrow, slow-conducting isthmus dependent left atrial reentry developing after ablation for atrial fibrillation: ECG characterization and elimination by focal RF ablation.

INTRODUCTION: The complete circuit of reentrant left atrial tachycardias (LATs) occurring after ablation for atrial fibrillation (AF) has not been well described. Identifying discrete isthmuses critical to these LATs may simplify their elimination by catheter ablation. METHODS AND RESULTS: Fifteen patients (all male, 56 +/- 8 years) with 15 reentrant LATs following AF ablation underwent activation and entrainment mapping. Eleven patients (11 LATs) had a single localized site with low amplitude (0.16 +/- 0.05 mV), fractionated long duration (131 +/- 23 msec) electrograms coinciding with an isoelectric interval of 106 +/- 24 msec between flutter waves on all 12 ECG leads. Three-dimensional mapping and entrainment revealed this site to be a narrow markedly slowly conducting isthmus adjacent to ablated left (n = 8) or right (n = 3) pulmonary vein (PV) ostia, and critical to nine small diameter (15 +/- 3 mm) and two large diameter (49 +/- 2 mm) circuits. One radiofrequency (RF) application on this isthmus eliminated LAT in all 11 patients. Four patients (four LATs) with large circuits around the mitral annulus and/or PV ostia lacked isoelectric ECG intervals and slow-conducting isthmuses and required multiple RF applications across anatomically wide, rapidly conducting isthmuses. CONCLUSION: Focally ablatable narrow isthmuses of slow conduction are critical for the majority of reentrant LAT occurring after ablation for AF. The role and presence of these isthmuses can be anticipated by observing significant isoelectric intervals between flutter waves on all 12-surface ECG leads. Their distinctive electrophysiological characteristics allow their identification and elimination by simple RF ablation.

High-flow perfusion of sheaths for prevention of thromboembolic complications during complex catheter ablation in the left atrium.

INTRODUCTION: Mechanisms for thromboembolic complications during complex ablation procedures in left atrium (LA) have not been defined. The aim of this study was to determine the effect of the perfusion rate of the transseptal sheath on the incidence of thromboembolic complications during catheter ablation for atrial fibrillation (AF) or LA macroreentrant tachycardia. METHODS AND RESULTS: We analyzed clinical and procedural data from 86 consecutive patients (153 procedures) referred for catheter ablation of AF (74 patients) or LA macroreentrant tachycardia (12 patients). The transseptal sheath was continuously perfused at a low flow rate (3 mL/hour) for the first 32 patients and at a high flow rate (180 mL/hour) for the subsequent 54 patients. Ablation was mainly performed using map-guided isolation of pulmonary veins for AF and three-dimensional electroanatomic mapping for LA macroreentrant tachycardia. Five patients (6% of patients and 3.5% of procedures) developed a cerebral thromboembolic complication, all during procedures using low-flow perfusion. Sheath perfusion rate and total procedure duration were the two variables significantly associated with the occurrence of stroke (P = 0.013 and 0.001, respectively). After adjustment in a multivariable analysis, sheath perfusion rate remained the only risk factor for stroke. The risk was 17 times higher using low-flow than high-flow perfusion (odds ratio 17.26, 95% confidence interval 1.14-260.81, P = 0.04). No other clinical or procedural parameters had any significant effect. CONCLUSION: Sheath perfusion rate is an important determinant of the risk factor for stroke during complex LA ablation procedures. Continuous high-flow perfusion appears to be effective in preventing this complication.

Catheter ablation of sinoatrial re-entry tachycardia in a 2 month old infant.

Successful catheter ablation of sinoatrial re-entry tachycardia in an infant has not been previously reported. This procedure is described in a 2 month old boy with tachycardia induced cardiomyopathy.

[Efficacy of radiofrequency catheter ablation in a patient with sinus node reentrant tachycardia].

We performed electrophysiological study and catheter ablation on a 62-year-old patient with supraventricular tachycardia(SVT). This SVT was reproducibly initiated and terminated by atrial stimulation during the electrophysiological testing. The P-wave morphology and atrial activation sequence of intracardiac electrograms were identical to those in normal sinus rhythm. SVT was terminated with carotid sinus massage that increased vagal tone, and for this reason, the reentry circuit of SVT could be localized in sinus node. On the basis of these findings, the SVT was diagnosed as sinus node re-entrant tachycardia and was successfully eliminated by radiofrequency catheter ablation. Radiofrequency catheter ablation would be effective in patients with sinus node reentrant tachycardia refractory to anti-arrhythmic drugs. It should, however, be performed with careful consideration to the influence of the sinus node.

Electroanatomic characterization of conduction barriers in sinus/atrially paced rhythm and association with intra-atrial reentrant tachycardia circuits following congenital heart disease surgery.

INTRODUCTION: The electrophysiologic mechanism of intra-atrial reentrant tachycardia (IART) is generally thought to be a macroreentrant circuit revolving around a nonconductive or highly anisotropic barrier. However, the electrical and anatomic substrate that supports these circuits has been incompletely defined. Our objectives were to characterize the atria of patients with IART using electroanatomic mapping in sinus or atrially paced rhythm and to determine whether electrical barriers identified in sinus/atrially paced rhythm are associated with IART circuits. METHODS AND RESULTS: Eighteen patients with IART and a remote history of repaired or palliated congenital heart disease were studied [8 biventricular repair, 8 single ventricle palliation (7 Fontan), and 2 Mustard repair]. Thirteen patients had a right AV valve. In sinus/atrially paced rhythm, electrical evidence of a crista terminalis was identified in 11 patients, an atriotomy in 12, and > or = 1 right atrial free-wall scar in 11. In 26 IART circuits characterized, 12 used the right AV valve as a central obstacle, 6 used a right atrial free-wall scar, 3 used an atriotomy, 3 used the crista terminalis, and 2 circuits used an atrial septal scar. All central obstacles used by IART circuits were identified in sinus/atrially paced rhythm. CONCLUSION: The crista terminalis, atriotomy, and right atrial scars can be identified in patients with repaired congenital heart disease by electroanatomic mapping in sinus/atrially paced rhythm. These conduction barriers frequently function as the central obstacle for IART. Demonstration of such features may help focus investigational mapping without reliance on spontaneous initiation of the tachycardia.

[Incidence and prognosis of atrioventricular block induced by radiofrequency ablation of intranodal reentrant tachycardia. A multicenter study]. / Incidence et pronostic du bloc auriculoventriculaire induit par l'ablation par radiofréquence des tachycardies par réentrée intranodale. Etude multicentrique.

The object of this study was to assess the incidence and significance of atrioventricular block (AVB) induced by radiofrequency ablation of intranodal reentrant tachycardias. The study population was 18 patients aged 44 to 83, selected from a total population of 144 patients treated for recurrent, refractory tachycardias. These patients developed complete AVB (9 cases), 2nd degree ABV (3 cases) and 1st degree AVB (6 cases) either immediately or in the chronic phase after radiofrequency ablation. The outcomes were as follows: 1. In the 9 patients with complete AVB, the block regressed in a period ranging from 7 seconds to 5 minutes. It recurred as complete AVB 1 to 4 days later in 2 patients, and regressed again after a maximum of 10 days. One 47 year old woman had definitive complete AVB; 2. In the 3 patients with 2nd degree AVB, the block regressed within 7 days; 3. In the 6 cases of 1st degree AVB, 2 patients developed transient complete AVB the following day. The possible causes of AVB were: increased vagal tone in 1 case, ablation of the rapid pathway located in a postero-septal site in 8 cases and, in the remainder, pre-existing conduction defects. The authors conclude that transient complete AVB is common and usually has a good prognosis. Definitive complete AVB is a rare but possible (0.7%) complication of radiofrequency ablation of reentrant intranodal tachycardias; other forms of AVB generally regress quickly and, although they may recur within days, they carry a good prognosis in the following months. However, long-term follow-up remains necessary.

Normal values for corrected sinus node recovery time in adolescents.

Sinus node recovery times have been used to evaluate sinus node function in adults and children. Normal values for corrected sinus node recovery time (CSNRT) are generally accepted as 275 and 500-550 msec in young children and adults, respectively. However, normal CSNRT values have not been determined for adolescent patients. Therefore, we mesured CSNRT in 29 consecutive patients, ages 12-17 years, who underwent electrophysiology testing as part of radiofrequency ablation. CSNRTs were performed by rapid atrial pacing for 30 seconds. Pacing cycle lengths were then shortened in 50-msec decrements to a minimum of 300 msec CSNRTs were determined by subtracting the patients' resting sinus cycle length from the maximal SNRT measured. The mean CSNRT was 323 +/- 61 msec (mean +/- SD, range 186-422 msec). A significant positive correlation between CSNRT and age was found. We conclude that the CSNRT value for the upper limit of normal in adolescents lies between the normal values previously determined for children and adults and is approximately 445 msec (mean + 2 SD). Because sinus node dysfunction is a well-recognized, long-term complication following surgical repair for complex congenital heart disease, this value becomes especially relevant as more children with congenital heart disease survive into adolescence.