Search

During catheter ablation (CA) of tachycardia, conventional point‐by‐point mapping may be hindered due to hemodynamic instability. We performed open‐window mapping (CARTO, Biosense Webster, USA) in a patient who developed hemodynamic instability during orthodromic atrioventricular reciprocating tachycardia (AVRT) and unwarranted induction of AVRT during attempts to map accessory pathway (AP) with ventricular pacing. With over 11,000 points acquired rapidly, the system accurately identified AP at the mitral valve (MV) annulus where the application of single radiofrequency (RF) lesion promptly eliminated AP's conduction. Our case illustrates the utility of open‐window mapping for the ablation of AVRT. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation (CA) remains challenging due to suboptimal success rates in persistent atrial fibrillation (AF). Existing mapping technologies cannot reliably distinguish sources in this patient population. Recently, the novel electrographic flow (EGF) mapping system was developed using a modified Horn‐Schunk optical flow algorithm to detect and quantify patterns of electrical wavefront propagation in the atria. Objectives: To test the hypothesis that targeted source ablation based on EGF mapping is superior to empiric AF ablation. Methods: We included all consecutive patients undergoing EGF guided ablation for persistent AF. All patients underwent pulmonary vein isolation (PVI) and were treated with the same EAM system (CARTO). The outcome of PVI+EGF guided CA was compared with data of PVI‐only procedures (PVI‐only group) and PVI plus additional empiric adjunctive linear and substrate ablations (PVI+LINES group). 12‐months outcome as freedom from AF and atrial tachycardia/flutter (AT/AFL), procedural safety and efficiency characterized by procedure duration, fluoroscopy use, radiofrequency applications and duration, were analyzed. Both intention‐to‐treat and per protocol analysis were conducted. Results: A total number of 70 patients (39 in PVI+EGF, 16 in PVI‐only and 15 patients in PVI+LINES group) were enrolled. Intention‐to‐treat analysis showed fewer AF recurrences in PVI+EGF as compared with the PVI‐only or PVI+LINES groups at 12 months (25.6% vs. 62.5% vs. 53.3%, p =.02). There were no differences in AT/AFL recurrence (17.9% vs. 37.5% vs. 20.0%, p =.37). Procedure times were longer in PVI+EGF group (p <.01), and there were no differences in fluoroscopy use (p =.67). Conclusion: Our data suggest that patients treated with EGF‐guided CA developed fewer AF recurrences. Although the procedure times are longer, it seems to be safe and offers a more targeted, patient‐specific ablation strategy beyond PVI than adjunctive empiric lines and substrate ablation in this complex group of patients. [ABSTRACT FROM AUTHOR]

Background: Post‐ablation atrial tachycardias (ATs) are characterized by low‐voltage signals that challenge current mapping methods. In this study, we analyzed common mistakes during activation mapping and delineated a mapping strategy for correct interpretation of tachycardia mechanisms in patients with challenging underlying substrate. Methods and results: Thirty‐one patients referred for AT ablation were selected for the study. Three types of incorrect activation patterns were identified, which were referred to as unrecognized block line (pseudo‐macroreentry and pseudo‐fig‐8 reentry), incorrect activation timing window of interest (WOI) (chaotic activation), and mis‐annotation of complex signals (multiple sites of "early meets late"). Pseudo‐macroreentry and chaotic activation occur in focal or localized reentry AT with the error related to the WOI selection (four cases), incorrect annotation of local activation time (six cases), or a previous line of atrial block in (seven cases). Pseudo‐fig‐8 reentry (five cases) and multiple sites of "early meets late" (nine cases) occur in macroreentrant AT with blocked areas and low‐voltage atrial substrate. All ATs were successfully eliminated at the origin site. Conclusions: We delineated a series of ATs in the setting of a disordered pattern of activation mapping encountered in patients after previous extensive ablation or atriotomy. The algorithm proposed rapidly corrects the activation map and identifies the mechanism of the AT. [ABSTRACT FROM AUTHOR]

Introduction: We report a case of a fetus with complex congenital heart disease and supraventricular tachycardia in the setting of maternal high grade atrioventricular block at 26 weeks' gestation. Methods and results: Electroanatomic mapping allowed successful implantation of a permanent pacemaker to provide adequate back‐up pacing in the mother with zero radiation exposure, thus allowing safe delivery of transplacental anti‐arrhythmic medications to reduce the fetal arrhythmia burden and optimize the fetal ventricular rate. Conclusion: This is the first reported case of using electroanatomic mapping, with zero fluoroscopy use, for pacemaker lead placement and for a novel indication. [ABSTRACT FROM AUTHOR]

The management of ventricular arrhythmias (VA) in the presence of an apparently normal heart represents a major clinical challenge and a main field of clinical research. In the past years, new imaging techniques and the spreading of new generation genetic testing have improved our knowledge of the pathogenesis of apparently idiopathic VA. However, in the absence of specific recommendations, the type and the number of noninvasive and invasive studies necessary to rule out a possible underlying cause of VA or sudden cardiac death remain extremely variable. Therefore, in many patients the underlying cardiac disease is not recognized, and a possible specific therapeutic approach cannot be initiated. Endomyocardial biopsy (EMB) can provide a significant contribution to the identification of myocardial disorders causing VA but has never been definitively included in the routine diagnostic work‐up of these patients due to the possible sampling error particularly in disorders with a focal or patchy distribution. Three‐dimensional electroanatomic mapping (EAM) may guide EMB allowing to draw myocardial samples from abnormal voltage, areas of the ventricular wall, thus reducing sampling error and increasing the sensitivity of EMB. The systematic association of EAM with EMB represents a crucial approach to characterize the pathological substrate of electroanatomic abnormalities and VA and to further clarify the arrhythmogenic mechanisms of acquired and also inherited arrhythmic disorders. [ABSTRACT FROM AUTHOR]

Background: Mapping and ablation of fractionated electrograms is a common treatment for scar‐based ventricular tachycardia (VT). An automated algorithm has been developed for rapid "fractionation mapping." Methods: Electroanatomic maps from 21 ablation procedures (14 scar‐based VT and seven control idiopathic VT/premature ventricular contractions with normal voltage) were retrospectively analyzed using the Ensite Precision fractionation map (fMap; Abbott Laboratories; Abbott Park, IL, USA) algorithm. For each study, voltage maps and 30 fMaps were generated using combinations of parameters: width (5, 10, 20 ms), refractory time (15, 30 ms), sensitivity (0.1, 0.2 mV), and fractionation threshold (2, 3, 5). Parameter sensitivity was assessed by overlap of fractionated areas (fArea) with successful VT ablation sites (defined by entrainment and/or pace mapping). Specificity was assessed by presence of fractionated areas in control patients. Results: Of the 30 fMap parameter sets tested, seven identified >50% of scar‐based VT ablation sites, and 26 contained <5 cm2 fractionation on control fMaps. Three combinations of fMap width/refractory/sensitivity/threshold parameters met both of the above criteria, and 20/30/0.1/2 identified the most VT ablation sites (79%) and generated 42.3 ± 28.2 cm2 of fArea on scar‐based VT maps compared with 4.9 ± 3.2 cm2 on control maps (P = .001). None of the control patients and 23% of the scar‐based VT patients had VT recurrence at mean 15 month follow‐up. Conclusion: Careful selection of signal processing parameters optimizes sensitivity and specificity of automated fractionation mapping for scar‐based VT. Real‐time use of fMap algorithms may reduce VT ablation procedure time and improve substrate modification, which may improve outcomes. [ABSTRACT FROM AUTHOR]

Background: The conventional method of device implantation requires fluoroscopic guidance. With the guidance of three‐dimensional (3‐D) navigation systems, devices can be implanted with minimal use of fluoroscopy. To date, this technique has been reported in several case reports in young, pregnant patients. However, this technique has not been widely utilized by electrophysiologists, despite offering several benefits, including reduced radiation exposure for the patient and the operator. Methods: In this study, we evaluated 18 patients who successfully underwent device implantation with limited use of fluoroscopy under the guidance of the EnSite Precision 3‐D mapping navigation system (Abbott, St. Paul, MN, USA). In most of the patients, the total fluoroscopy time was 1 s, accounted by a single postprocedural frame to insure appropriate lead placement. Results: A total of 19 leads were implanted in 18 patients (14 male, four female) using the electroanatomical mapping (EAM)‐guided technique. A total of 19 leads were implanted in 15 patients (10 male, five female) using the conventional method. The average length of stay was 1.20 days in the EAM group compared to 1.47 days in the conventional group (P = .10). Majority of the devices implanted in both groups were single‐chamber implantable cardiac defibrillators (VVI ICD, Abbott) implanted for cardiomyopathy with left ventricular ejection fraction persistently below 35%, including 88% (16/18) in the EAM group compared to 73% (11/15) in the conventional group. No periprocedural or immediate postprocedure complications were reported in either group. Device parameters, including impedance, capture time, and capture voltage, showed no significant difference in either group. Total radiation time and radiation dose were markedly lower in the EAM‐guided implantation group. Conclusions: In patients who meet appropriate criteria for device implantation, the use of EAM system offers a safe, practical, efficacious alternative method to device implantation, with significant reduction in radiation time and dose. [ABSTRACT FROM AUTHOR]

Background: Patients with systemic right ventricle (RV) often develop progressive heart failure and may benefit from cardiac resynchronization therapy (CRT); however, the optimal strategy for CRT has not been defined. Methods: A retrospective review of all the patients with systemic RV failure undergoing a hybrid transcatheter‐surgical approach was performed. Procedural technique and outcomes are reported. Results: Six patients underwent detailed electroanatomical mapping of the systemic RV followed by a new hybrid approach targeting latest endocardial activation, which was followed by focused epicardial mapping. The exact site of latest endocardial activation was variable but localized to the basolateral RV in all cases. Sites of latest activation tended to be more superior during contralateral ventricular pacing versus intact atrioventricular conduction (P = 0.06). Latest endocardial activation at the targeted site occurred at 157 ms (interquartile range [IQR] = 120‐181 ms) and corresponding epicardial activation at 174 ms (IQR = 140‐198 ms), after the onset of the QRS complex. Following the hybrid CRT, the QRS duration decreased from a median of 193 to 147 ms and the fractional area of change increased from a median of 15.5% to 30% (P < 0.001). Patients were discharged to home after a median of 4 days. Of the three patients who were initially referred for transplant evaluation, two (66%) of them no longer met the criteria following CRT. Conclusions: Whereas latest endocardial activation for the systemic RV appears to localize to the basolateral region, the optimal lead position may be variable. An approach utilizing endocardial mapping followed by a limited surgical incision and confirmation of latest activation may result in minimally invasive surgery and a favorable acute CRT response. [ABSTRACT FROM AUTHOR]

Background Electroanatomic mapping systems track the position of electrodes in the heart. We assessed the feasibility of characterizing left ventricular (LV) performance during cardiac resynchronization therapy (CRT) implant utilizing an electroanatomic mapping system to track the motion of CRT lead electrodes, thus deriving ventricular contractility surrogates. Methods During CRT implant, atrial, right ventricular (RV), and LV leads were connected to the EnSite NavX™ mapping system (St. Jude Medical Inc., St. Paul, MN, USA). The relative displacement of electrodes was averaged over 10 cardiac cycles during RV, LV, and biventricular (BiV) pacing in DOO mode. Three contractility surrogates indicative of ventricular performance were extracted from the RV-LV distance waveform: systolic slope (SS), time to peak systolic contraction (TPSC), and fractional shortening (FS). Results In the 20 patients included, there were detectable differences in each of the three contractility surrogates responding to the different pacing configurations. Median SS varied 42%, median TPSC varied 35%, and median FS varied 19% across RV, LV, and BiV pacing interventions. The RV-LV distance waveform showed subtle sensitivity to varying pacing timing cycles when measured in a subset of patients. For all pacing configurations, RV-LV distance waveforms were stable during 2-minute recordings. Conclusions Tracking the motion of CRT pacing electrodes with a mapping system to derive contractility surrogates during implant is feasible. [ABSTRACT FROM AUTHOR]

Background Anatomical considerations and risks related to x-ray exposure make atrioventricular nodal reentrant tachycardia (AVNRT) ablation in pediatric patients a concerning procedure. We aimed to evaluate the feasibility, safety, and efficacy of performing fluoroless slow-pathway cryoablation guided by the electroanatomic (EA) mapping in children and adolescents. Methods Twenty-one consecutive patients (mean age 13.5 ± 2.4 years) symptomatic for AVNRT were prospectively enrolled to right atrium EA mapping and electrophysiological study prior to cryoablation. Cryoablation was guided by slow-pathway potential and performed using a 4-mm-tip catheter. Results Sustained slow-fast AVNRT was inducible in all the patients with a dual AV nodal physiology in 95%. Acute success was achieved in 100% of the patients with a median of two cryo-applications. Fluoroless ablation was feasible in 19 patients, while in two subjects 50 seconds and 45 seconds of x-ray were needed due to difficult progression of the catheters along the venous system. After a mean follow-up of 25 months, AVNRT recurred in five patients. All the recurrences were successfully treated with a second procedure. In three patients, a fluoroless cryoablation with a 6-mm-tip catheter was successfully performed, while in the remaining two patients, a single pulse of 60 seconds of radiofrequency energy was applied under fluoroscopic monitoring. No complications occurred. Conclusions Combination of EA mapping systems and cryoablation may allow to perform fluoroless slow-pathway ablation for AVNRT in children and adolescents in the majority of patients. Fluoroless slow-pathway cryoablation showed a high efficacy and safety comparable to conventional fluoroscopy guided procedures. [ABSTRACT FROM AUTHOR]

Catheter ablation of periatrioventricular (peri-AV) nodal atrial tachycardias (AT) from the noncoronary aortic cusp (NCC) can be challenging due to the close proximity of the AV node In such cases, intracardiac echocardiography (ICE) together with three-dimensional mapping system can be helpful in guiding the ablation catheter and in assessing the anatomic relationship of the aorta to the surrounding structures. We report two patients with AT originating near the AV node who underwent successful catheter ablation from the NCC. ICE proved useful in positioning the ablation catheter within the aortic cusps. Electroanatomic mapping enabled tagging the earliest activation site and renavigation back. (PACE 2013; 36:e19-e22) [ABSTRACT FROM AUTHOR]

A 29-year-old man presenting with syncopal ventricular tachycardia was diagnosed with arrhythmogenic right ventricular (RV) cardiomyopathy. Cardiac magnetic resonance imaging (MRI) revealed an unequivocal dyskinetic segment at the basal portion of the RV lateral free wall. Three-dimensional electroanatomic voltage mapping using the EnSite NavX™ system recorded a low voltage area corresponding to the diseased portion of the right ventricle identified by MRI. This report describes concordance between cardiac MRI and this novel mapping system in arrhythmogenic RV cardiomyopathy. [ABSTRACT FROM AUTHOR]

GUREVITZ, O.T.,et al.: Use of Advanced Mapping Systems to Guide Ablation in Complex Cases: Experience with Noncontact Mapping and Electroanatomic Mapping Systems. Objective:This report describes our experience with noncontact mapping and electroanatomic mapping in complex ablations, which are defined as ablations done after failure of conventional ablation.Material and Methods:Patients were included (N= 68; 49% with structural heart disease) in whom previous ablation failed and in whom a second procedure was done with advanced mapping. Non-contact mapping was used in 17 patients, electroanatomic mapping in 36, and both noncontact and electroanatomic mapping in 15. Arrhythmias included focal atrial tachycardia (n= 16), reentrant atrial tachycardia (n= 14), right ventricular outflow tachycardia (n= 10), post-myocardial infarction ventricular tachycardia (n= 9), and others (n= 19).Results:Acute success at the second ablation was achieved in 79% of patients. At 20± 9 months after the procedure, 69% of these patients reported having significantly fewer symptoms than before the second ablation, and 51% were free of symptoms. Only 16% were using antiarrhythmic medications. Complications included a small pericardial effusion in two patients, hypotension in one patient, and a femoral pseudoaneurysm in another.Conclusions:Advanced mapping is a useful and safe adjunct for catheter ablation after ablation has failed in patients with complex substrate.(PACE 2005; 28:316–323) [ABSTRACT FROM AUTHOR]

CHAUHAN, V.S., et al.: Magnetoelectroanatomic Mapping of Arrhythmias in Structural Heart Disease Using a Novel Multielectrode Catheter: Early Clinical Experience. Electroanatomic mapping with CARTO requires point-by-point acquisition using the mapping catheter's bipolar tip electrode. This study evaluates the utility of a novel 26-electrode catheter (Qwikstar) for electroanatomic mapping of arrhythmias in patients with structural heart disease. The multielectrode catheter acquires activation times and anatomic data simultaneously from its tip and shaft electrodes. Eight patients (6 men, 2 women, age 47 years [37, 65]) with atrial tachycardia (n = 6) and ventricular tachycardia (n = 2) due to congenital heart disease (n = 4) and cardiomyopathy (n = 4) were studied. Using the multielectrode catheter, the electroanatomic map was constructed in two stages: (1) a scout map using the minimum number of tip and shaft electrode data points that covered > 70% of the tachycardia cycle length and/or the majority of the chamber volume, and (2) a complete map using additional tip electrode data points. A total of 36 (28, 510) tip electrode and 38 (34, 42) shaft electrode electroanatomic data points comprised the scout map. The complete map was constructed with a total of 102 (73, 134) tip electrode electroanatomic data points. In three patients, the scout map suggested a cavotricuspid isthmus dependent atrial flutter that was confirmed with the complete map. In another four patients, the scout map identified the earliest site of focal activation, which was also confirmed with the complete map. In comparison, activation mapping using the bipolar catheter (Navistar) in a group of arrhythmia-matched control subjects required 210 (180, 320) electroanatomic data points (P = 0.012 vs multielectrode catheter complete map). In conclusion, for large macroreentrant or focal arrhythmias in patients with structural heart disease, the multielectrode catheter can generate a scout map that accurately guides complete electroanatomic mapping using fewer point-by-point acquisitions than the bipolar catheter. (PACE 2004; 27:1077–1084) [ABSTRACT FROM AUTHOR]

Arrhythmogenic right ventricular dysplasia is a structural heart disease characterized by fibrofatty degeneration of right ventricular myocardium and arrhythmias of right ventricular origin. The aim of this study was to characterize endocardial right ventricular activation by electroanatomic mapping as a guide for catheter ablation in patients with arrhythmogenic right ventricular dysplasia. Electroanatomic mapping and entrainment procedures were performed in 5 patients with arrhythmogenic right ventricular dysplasia. Endocardial mapping during ventricular tachycardia demonstrated a focal activation pattern with radial spreading of activation from a site of earliest ventricular activation in all directions. Right ventricular activation time (127 ± 34 ms) was markedly shorter than tachycardia cycle length (415 ± 92 ms). The site of earliest ventricular activation was found in an aneurysmal outflow tract (n = 2), at the border of aneurysms near the tricuspid annulus (n = 2), and at the apex of the right ventricle (n = 1). Entrainment mapping criteria of these areas of earliest endocardial activity were consistent with exit sites of a reentrant circuit in an area of abnormal myocardium. Fractionated potentials were found 61 ± 29 ms before the onset of the QRS complex at these sites. Catheter ablation rendered the “clinical“ ventricular tachycardia noninducible in four patients but “nonclinical” faster ventricular tachycardias were inducible in three patients. During the follow-up of 7 ± 3 months after ablation, the frequency of therapies in 4 patients with an implantable cardioverter defibrillator decreased from 49 ± 61 episodes per month before ablation, to 0.3 ± 0.5 episodes per month after ablation (P < 0.05). Electroanatomic mapping during ventricular tachycardia facilitates localization of exit sites in relation to aneurysms in diseased right ventricle and may guide catheter ablation in patients with arrhythmogenic right ventricular dysplasia. (PACE 2003; 26:1308–1316). [ABSTRACT FROM AUTHOR]

A 57-year-old woman with frequent isolated and repetitive premature atrial contractions initiating paroxysmal atrial fibrillation, underwent electrophysiological study and catheter ablation. A real-time three-dimensional map of the left atrium was reconstructed using a nonfluoroscopic navigation system. By means of a deflectable decapolar catheter, the left superior pulmonary vein (PV) was identified as the arrhythmogenic vein, and PV potentials were found in the left inferior and right superior veins. Ablation was performed under electroanatomic guidance. After circumferential ablation outside the PV ostia, dissociation of PV potentials was obtained in the left superior vein, and PV potentials were eliminated in the other two veins. (PACE 2003; 26:1413–1416). [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the clinical use of a new three-dimensional mapping system as a guide for catheter ablation of ectopic atrial tachycardia. A series of 42 consecutive patients with drug refractory ectopic atrial tachycardia was studied in a prospective observational trial with the electroanatomic mapping system CARTO. The arrhythmogenic focus was found in the right atrium in 30 patients and in the left atrium in 12 patients. The construction of a complete electroanatomic map of the right or left atrium was possible in 37 of 42 consecutive patients with ectopic atrial tachycardia. Mean activation time of the right atrium, including the proximal coronary sinus, was 94 ± 25 ms for right atrial tachycardias; left atrial activation time during left atrial tachycardias was 86 ± 17 ms. Average mapping time was 30 minutes for right atrial tachycardias and 22 minutes for left atrial tachycardias, allowing the collection of 86 ± 50 and 65 ± 28 catheter positions, respectively. The size of the area of earliest atrial activation calculated from the electroanatomic map amounted to 0.6 ± 0.4 cm² in right atrial tachycardias and 1.0 ± 0.9 cm² in left atrial tachycardias. In the right atrium the most common locations of the 33 arrhythmogenic foci in 30 patients were the high or mid-lateral right atrium (n = 10) and the inferoparaseptal region near the coronary sinus ostium (n = 7). Ectopic left atrial foci were most commonly located in an inferior position near the mitral annulus (n = 5) and in proximity to the ostium of the pulmonary veins (n = 4). Biatrial electroanatomic mapping allowed visualization of earliest right atrial activation during left atrial tachycardia at the high interatrial septum or near the coronary sinus ostium. Catheter ablation was successful in 85% of right atrial tachycardias and 82% of left atrial tachycardias. In patients with ectopic atrial tachycardia electroanatomic mapping is a safe and feasible technique that allows three-dimensional visualization of the automatic focus in a precise anatomic reconstruction of the atria. This novel mapping technology facilitates catheter ablation of complex ectopic atrial tachycardia. [ABSTRACT FROM AUTHOR]

With conventional techniques, RF catheter ablation is difficult in patients with unstable VT or with multiple VTs. The feasibility of RF catheter ablation guided by three-dimensional electroanatomic mapping technique in patients whose implanted ICD continued to deliver multiple shocks due to VT despite use of antiarrhythmic medications was assessed in 19 patients (15 men, 4 women: mean age [± SD] 70 ± 7 years). All had a prior history of MI and subsequently had received an ICD due to VT. During the 12-week preablation period, these patients received 31 ± 15 shocks (range 4-62 shocks) due to refractory monomorphic VTs. An electroanatomic mapping technique using the CARTO system was performed to delineate scar tissue. RF catheter ablation was then performed at appropriate sites identified by pacemapping and by substrate mapping. Seventeen patients were on amiodarone at the time of ablation. Twenty-seven VTs were documented clinically, and 45 were induced during electrophysiological evaluation. Of the 45 tachycardias induced, 38 VTs were targeted for ablation. Catheter ablation was performed during sinus rhythm in 31 episodes and during VT in 7 episodes. During a mean follow-up of 26 ± 8 weeks (range 18-48 weeks),13 (66%) patients had no recurrence of VT (P < 0.0001) and antiarrhythmic drugs were discontinued or the number of medications reduced in 17 patients (P < 0.0001). Electroanatomic mapping is helpful in identifying sites for catheter ablation in highly symptomatic patients with refractory VT associated with myocardial scarring. [ABSTRACT FROM AUTHOR]

The accuracy of conventional techniques in localizing previous radiofrequency (RF) ablation sites and thus breakthrough sites of recurrent atrial flutter is somewhat limited. We investigated the role of electroanatomic mapping for identifying breakthrough sites or "gaps" at the tricuspid annulus and inferior vena cava (IVC)/eustachian ridge isthmus to help RF ablation in patients with recurrent typical flutter. Twelve patients (8 men, 4 women, age 63 ± 10 years) with recurrent typical atrial flutter were included in the study. An electroanatomic mapping system (CARTO) was used to create a voltage map and activation and propagation patterns in the right atrium. Detailed voltage, activation, and propagation mapping of the tricuspid annulus and IVC/eustachian ridge isthmus allowed precise identification of gaps in all 12 patients at the tricuspid annulus (eight sites), IVC ridges (two sites), mid-isthmus region (one site), and tricuspid annulus and IVC ridges (one site). Radiofrequency energy directed at these sites eliminated atrial flutter in all 12 patients, confirmed by noninducibility of atria! flutter and demonstration of conduction block during atrial pacing on either side of the lesion lines. During a mean follow-up of 14.8 ± 3.5 months (range 3-19 months), paroxysmal atrial flutter recurred in only one patient and was subsequently treated with amiodarone, although this had been ineffective prior to ablation. Electroanatomic mapping can precisely identify gaps in the lesion line responsible for breakthrough of recurrent typical atrial flutter at the tricuspid annulus and at the IVC/eustachian ridge isthmus. These sites can be targeted with RF ablation with a high degree of success. [ABSTRACT FROM AUTHOR]

This study sought to validate the accuracy of magnetic electroanatomic mapping (MEAM) for determining cardiac chamber size in a clinically relevant situation. The authors chose to compare LA size measured by MEAM to that assessed by two-dimensional guided M-mode echocardiography. The study included 37 patients with drug refractory paroxysmal atrial fibrillation who underwent two-dimensional echocardiography and a detailed MEAM of the LA. The entire LA was mapped with a mean of 132 ± 50 points with attention to identifying the mitral annulus and posterior wall of the LA. The MEAM measurement of LA size was taken as the distance from the anterior wall of the LA to the posterior wall in a plane parallel to the mitral valve annulus at atrial end-diastole. LA dimension determined by M-mode echocardiography was assessed in a plane parallel to the mitral valve annulus in the parasternal long-axis view during atrial end-diastole. LA size assessed by M-mode echocardiography was 41.2 ± 5.0 versus 40.9 ± 4.5 mm as assessed by MEAM, with good correlation (r = 0.87, P < 0.001). Only three patients had a difference in LA size that was > 0.3 cm between the two measurement techniques. Thus, it appears that LA anteroposterior dimension as determined by electroanatomic mapping is similar to that determined by two-dimensional guided M-mode echocardiography. MEAM appears to be an accurate method by which LA size can be assessed in patients with drug refractory atrial fibrillation undergoing left atrial ablation procedures. [ABSTRACT FROM AUTHOR]

This report describes a 2-year-old mule infant after repair of complicated congenital bead anomalies including common atrioventricular canal (CAVC), in which macroreentrant atrial flutter around the CAVC was demonstrated by electroanatomic mapping (CARTO) using a single catheter. Radiofrequency catheter ablation at the isthmus between the CAVC and the inferior vena cava eliminated the atrial flutter successfully. [ABSTRACT FROM AUTHOR]