Electroanatomic Activation Mapping Research Articles

Case report: Para Hisian Atrial Tachycardia

Case report: Para Hisian Atrial Tachycardia

Endocardial ablation at the mitral valve vestibule and its surroundings for the treatment of arrhythmias linked to the greater cardiac vasculature.

The role of the epicardial vasculature in supraventricular and ventricular arrhythmias was described in clinical studies as well as its treatment by intravascular point ablation or alcohol injection. We report on a case series of patients with different arrhythmias linked to an epicardial site of origin with evidence supporting transmural extensions that were targeted for ablation with successful outcomes. The records of patients who has catheter ablation for Supraventricular or Ventricular arrhythmias between 2015 and 2020 was searched for patients with (1) arrhythmias linked to the epicardial vasculature and (2) findings to support an endocardial connection to the epicardial vasculature by activation mapping, pace mapping, or differential pacing, and (3) were successfully ablated via an endocardial approach only. From the data searched, we identified five patients with the following arrhythmias left ventricular summit ectopy, peri-mitral atrial flutter, preexcitation with inducible atrioventricular reentry tachycardia (AVRT), and a concealed left side accessory pathway with inducible AVRT that were linked to the following vessels: Great Cardiac vein, persistent left superior vena cava, left coronary cusp, and left ventricular outflow tract. Endocardial connections were supported by a combination of electro anatomical activation mapping, pace-mapping, and differential pacing. Endocardial ablations performed in all patients were successful without complications. This report highlights a subset of patients with arrhythmias linked to the greater cardiac vascular system that can be safely and effectively ablated endocardially, given the limitations and possible complications of epicardial ablation within or in the proximity of the epicardial vasculature.

Non-invasive localization of premature ventricular focus: A prospective multicenter study

BackgroundAccurate localization of premature ventricular contractions (PVC) focus is a prerequisite to successful catheter ablation. ObjectiveThe objective was to evaluate the software View Into Ventricular Onset (VIVO) accuracy at locating the anatomical origins for premature ventricular contractions. The VIVO device noninvasively creates a model of the patient's heart and torso, with exact locations of 12‑lead ECG electrodes, and applies a mathematical algorithm from surface signals to determine the origin of the arrhythmia. We sought to compare the agreement between VIVO-predicted locations to invasive electroanatomical mapping results. Methods51 consecutive patients who presented for PVC ablations at the study centers were recruited. VIVO images were collected at baseline preprocedure and all patients underwent invasive electroanatomical activation mapping of the clinical arrhythmia. Pacing was performed in pre-specified locations in the right and/or left ventricle. The successful sites of ablation and the pacing locations were compared to VIVO predicted locations. The results were adjudicated by physician experts in a blinded fashion. ResultsSeven patients were excluded from analyses. VIVO accurately identified the origin of the clinical premature ventricular contractions in 44/44 patients (100.00%). The accuracy in identifying the paced location for all patients (right and left sides of the heart) was 99.5% using the VIVO system. No adverse events were reported. ConclusionsVIVO is a novel noninvasive system that could be used to help guide ablation procedures with a high degree of accuracy. The VIVO algorithm is easy to use and may be useful in the workflow for ventricular arrhythmia ablation.

Radiofrequency catheter ablation of focal atrial tachycardia: characteristics and results of a series in a tertiary hospital

Abstract Funding Acknowledgements Type of funding sources: None. Background Focal atrial tachycardia (AT) is a relatively uncommon arrhythmia with poor response to medical treatment. Radiofrequency (RF) ablation appears to be a good option for treatment of symptomatic patients (P). Purpose To describe the clinical characteristics, electrophysiological (EP) findings, safety and short-term efficacy of catheter ablation in P with AT. Methods Retrospective analysis of consecutive P submitted to AT ablation using electroanatomical mapping between 2015 and 2020. If the AT was not present spontaneously, pacing maneuvers (atrial drive or burst pacing with up to 3 extra-stimuli) and isoprenaline was employed until reproducible induction of an ectopic atrial rhythm. Radiofrequency (RF) ablation was delivered at the site of earliest activation after validation of local electrograms until non-inducibility. Results A total of 46P (61% female) were included, with a mean age of 48 ± 23 years (minimum 8 months, maximum 86 years). Idiopathic AT was observed in 47,8%, while 52.2% had other relevant comorbidities (chronic pulmonary disease 17.4%; previous cardiac surgery 8,7%; congenital heart disease 10.9%; coronary artery disease 6.5%). Despite anti-arrhythmic therapy, daily palpitations were present in 87% of the cases and dizziness or syncope occurred in 22%). Nearly half (47.8%) had previously sought urgent medical care and 30.4% had a hospital admission due to arrhythmia. The clinical arrhythmia was documented in 34P (47.8% by 12-lead electrocardiography and 26.1% in 24h Holter monitoring). During the EP study a focal AT was documented in all P (spontaneously in 54.3% and induced with pacing maneuvers in 45.7%). AT origin after electroanatomical activation mapping is depicted in figure 1. After focal RF ablation, a second AT was induced in 16P (34.8%) and a new ablation was performed in 15 cases (93.8%). Total RF time was 508 ± 386 sec. One P developed right phrenic nerve palsy after ablation on the lateral wall of the right atrium. No other complications were noted. On follow-up (mean 320 ± 92 days), symptoms improved in 88.1% of the P, with a 3-fold decrease in urgent medical care visits and hospital admission for arrhythmia. Three P (8.7%) were submitted to a new EP study, in which an AT was documented and ablated in 2P. Conclusion AT is a very symptomatic arrhythmia, associated with increased usage of hospital resources and poor response to antiarrhythmic therapy. Ablation is an efficient treatment option, with a high success rate, low rate of complications and short-term clinical benefits. Abstract Figure. Distribution of focal atrial tachycardia

Injectable conductive hydrogel restores conduction through ablated myocardium.

Therapies for substrate-related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization. A nanocellulose carbon nanotube-conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue. The conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The direct current conductivity under aqueous conduction was 4.3 × 10-1 S/cm. In four canine hearts, when compared with the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of the conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation restored through the ablated tissue. Gross specimen examination demonstrated retention of the hydrogel within the tissue. This proof-of-concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long-term retention and biocompatibility of the hydrogel through in vivo experimentation.

Slow Conducting ElectroanatomicIsthmuses: An Important Link BetweenQRS Duration and Ventricular Tachycardia inTetralogyof Fallot.

This study sought to evaluate the influence of slow conducting anatomic isthmuses (SCAI) as dominant ventricular tachycardia (VT) substrate on QRS duration. QRS prolongation has been associated with VT in repaired tetralogy of Fallot. Seventy-eight repaired tetralogy of Fallot patients (age 37 ± 15 years, 52 male, QRS duration 153 ± 29 ms, 67 right bundle branch blocks [RBBB]) underwent programmed stimulation and electroanatomic activation mapping during sinus rhythm. Right ventricular (RV) surface, RV activation pattern, RV activation time, conduction velocity at AI, and remote RV sites were determined. Twenty-four patients were inducible for VT (VT+); SCAI was present in 22 of 24 VT+ but only in 2 of 54 patients without inducible VT (VT-). Conduction velocity through AI was slower in VT+ patients (median of 0.3 [0.3 to 0.4] vs. 0.7 [0.6 to 0.9] m/s; p < 0.01) but conduction velocity in the remote RV did not differ between groups. In non-RBBB, QRS duration was similar in VT+ patients (n= 6) and VT- patients (n= 5), but RV activation within SCAI exceeded QRS offset in VT+ patients (37 ± 20 ms vs. -5 ± 9 ms, p< 0.01). In RBBB, both QRS duration and RV activation time were longer in VT+ patients (n= 18, 17 of 18 QRS > 150 ms) compared with VT- patients (n= 49, 27 of 49 QRS > 150 ms) (173± 22 ms vs. 156 ± 20 ms; p< 0.01; 141 ± 22 ms vs. 129± 21 ms; p= 0.04). In VT+ patients, QRS prolongation >150ms (n= 17) was due to SCAI or blocked isthmus in 15 patients (88%) and 1 (6%). In contrast, in VT- patients, QRS prolongation >150 ms (n= 27) was due to enlarged RV or blocked isthmus in 10 patients (37%) and 8 (30%), but due to SCAI in only 1 (4%). After exclusion of a severely enlarged RV, a QRS duration >150 ms was highly predictive for SCAI/blocked AI (OR: 17; 95% CI: 3.3 to 84; p< 0.01). A narrow QRS interval does not exclude VT-related SCAI. In the presence of RBBB, SCAI further prolongsQRS duration. QRS duration >150 ms is highly suspicious for SCAI or isthmus block distinguishable by electroanatomic mapping.

Prevalence and predictive factors of left atrial tachycardia occurring after second-generation cryoballoon ablation of atrial fibrillation.

Assess the prevalence and predictors of left atrial tachycardia (LAT) after cryoballoon ablation of pulmonary veins. Patients who underwent catheter ablation of pulmonary veins with a second-generation cryoballoon for symptomatic paroxysmal (151 of 270, 56%) or persistent (119 of 270, 44%) atrial fibrillation were entered in a single-center prospective registry. Patients who experienced postcryoballoon LAT (pcryo-LAT) were selected on the basis of 12-lead ECG characteristics. Left atrial origin was confirmed during conventional EP study and electroanatomical activation mapping, and patients were treated by RF catheter ablation. Pcryo-LAT was observed in 15 (5.6%) of 270 patients and was attributed to a reentrant mechanism in 11 patients (73%). The other four cases of pcryo-LAT were due to focal atrial tachycardia associated with reconnection of one pulmonary vein. In comparison with patients who remained in sinus rhythm, LA area (HR=1.09; CI 1.01, 1.2; P=0.02), LVEF (HR=0.94; CI 0.90, 0.97; P<0.001), and LVEF<50% (HR=8.5; CI 3.1, 23.6; P<0.001) were predictors of pcryo-LAT. After multivariate Cox analysis, only left ventricular ejection fraction<50% remained predictive of pcryo-LAT, (HR=7.8, CI 2.3 26.7, P=0.002). With a mean survival of 23 months, 73% of patients who experienced pcryo-LAT were in sinus rhythm versus 78% of patients without pcryo-LAT (log rank P=0.85). The prevalence of pcryo-LAT in patients with atrial fibrillation is low. Left ventricular ejection fraction<50% is associated with an increased risk of pcryo-LAT. When treated by RF catheter ablation, the presence of pcryo-LAT is not a predictive factor of subsequent recurrence of atrial fibrillation during follow-up.

OP-079 [AJC » Transcatheter ablation for tachyarrhythmias - Supraventricular tachycardia] A Successful Ablation of Recurrent Atrial Flutter in a Patient with Coronary Bypass Surgery by Using Three Dimensional Electroanatomic Activation Mapping

OP-079 [AJC » Transcatheter ablation for tachyarrhythmias - Supraventricular tachycardia] A Successful Ablation of Recurrent Atrial Flutter in a Patient with Coronary Bypass Surgery by Using Three Dimensional Electroanatomic Activation Mapping

A Novel Annotation Technique During Mapping to Facilitate the Termination of Atrial Tachycardia Following Ablation for Atrial Fibrillation.

The treatment of atrial tachycardia (AT) occurring after ablation for atrial fibrillation (AF) is challenging. The most common ablation strategy relies on entrainment, and electroanatomic activation mapping (EAM) using a conventional window of interest (WOI), centered on the easily detectable atrial signal on the coronary sinus catheter. We describe a novel EAM annotation technique that uses a WOI starting 40 milliseconds prior to the P wave in order to detect the reentrant AT exit site. This WOI timing is based on the similarity between scar-related reentrant AT and scar-related ventricular tachycardia. Patients with AT after prior ablation for AF were included. The EAM of the AT was performed using the novel mapping annotation technique. The ablation was considered successful if the AT terminated during ablation at the site identified by this strategy. Twenty-eight patients with 36 ATs were included. The ATs were classified as follows: mitral annulus (13/36), roof (11/36), anterior/posterior/lateral left atrial wall (10/36), and RA (2/36). A complete EAM using the novel annotation technique was achieved in 34 of 36 AT's, encompassing 94 ± 6.5% of the cycle length. Low amplitude pre-P fractionated electrograms were found in 34 of 36 (94%) ATs and these occurred at a mean distance of 1.8 ± 1.2 mm from the "early-meets-late" line. Ablation at these areas resulted in termination of 34 of 36 ATs (94%). The novel EAM annotation allows the accurate detection of the critical isthmus of post-AF ablation AT. Ablation of these isthmuses results in termination of the AT in the vast majority of patients.

Electroanatomic Correlates of Depolarization Abnormalities in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

Epsilon waves and other depolarization abnormalities in the right precordial leads are thought to represent delayed activation of the right ventricular outflow tract in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). However, no study has directly correlated cardiac electrical activation with the surface ECG findings in ARVD/C. Thirty ARVD/C patients (mean age 32.7 ± 11.2years, 16 men) underwent endocardial and epicardial electroanatomical activation mapping in sinus rhythm. Twelve-lead ECGs were classified into 5 patterns: (1) normal QRS (11 patients); (2) terminal activation delay (TAD) (3 patients); (3) incomplete right bundle branch block (IRBBB) (5 patients); (4) epsilon wave (5 patients); (5) complete right bundle branch block (CRBBB) (6 patients). Timing of local ventricular activation and extent of scar was then correlated with surface QRS. Earliest endocardial and epicardial RV activation occurred on the mid anteroseptal wall in all patients despite the CRBBB pattern on ECG. Total RV activation times increased from normal QRS to prolonged TAD, IRBBB, epsilon wave, and CRBBB, respectively (103.9 ± 5.6, 116.3 ± 6.5, 117.8 ± 2.7, 146.4 ± 16.3, and 154.3 ± 6.3, respectively, P < 0.05). The total epicardial scar area (cm(2) ) was similar among the different ECG patterns. Median endocardial scar burden was significantly higher in patients with epsilon waves even compared with patients with CRBBB (34.3 vs. 11.3 cm(2) , P < 0.01). Timing of epsilon wave corresponded to activation of the subtricuspid region in all patients. We found that epsilon waves are often associated with severe conduction delay and extensive endocardial scarring in addition to epicardial disease. The timing of epsilon waves on surface ECG correlated with electrical activation of the sub-tricuspid region.

Efficacy of ablation at the anteroseptal line for the treatment of perimitral flutter

BackgroundLeft atrial flutter following atrial fibrillation (AF) ablation is increasingly common and difficult to treat. We evaluated the safety and efficacy of ablation of the anteroseptal line connecting the right superior pulmonary vein (RSPV) to the anteroseptal mitral annulus (MA) for the treatment of perimitral flutter (PMF). MethodsWe systematically studied patients who were previously treated with AF ablation and who presented to the electrophysiology laboratory with atrial tachyarrhythmias between January 2000 and July 2010. The diagnosis of PMF was confirmed by activation mapping and/or entrainment. After re-isolation of any recovered pulmonary vein, a linear radiofrequency (RF) ablation was performed on the line that connected the RSPV to the anteroseptal MA. In this analysis, we included only patients who were treated with an anteroseptal line for their PMF. ResultsAblation was performed at the anteroseptal line in 27 PMF patients (63±13 years; 9 women) who had undergone prior ablation for paroxysmal (n=3) or persistent (n=24) AF, using electroanatomic activation mapping (70% CARTO, 30% NavX). The anteroseptal ablation line was effective in 22/27 (81.5%) patients in the acute-care setting. Termination of AF to sinus rhythm occurred in 15/22 (68.2%) patients, and 7/22 (31.8%) patients׳ AF converted to another right or left atrial flutter. At the 6-month follow-up, 20% of patients demonstrated recurrent left atrial tachyarrhythmia. Only one patient required repeat ablation, and the remaining patients׳ condition was controlled with antiarrhythmic medications. No major procedural complications or heart block occurred. ConclusionAblation at the left atrial anteroseptal line is safe and efficacious for the treatment of PMF. Unlike ablation at the traditional mitral isthmus line, ablation at the left atrial anteroseptal line does not require ablation in the coronary sinus.

The presence of extensive atrial scars hinders the differential diagnosis of focal or macroreentrant atrial tachycardias in patients with complex congenital heart disease

Atrial tachycardias (ATs) frequently develop in patients with congenital heart defects (CHDs). This study aimed to evaluate the effects of extensive atrial scar formation on the total atrial activation time (TAAT) and its relation to the tachycardia cycle length (CL) to classify AT. Seventy-one patients were included and divided into two groups: patients without CHD (Group I, 35 patients) and with CHD (Group II, 36 patients). All patients underwent CARTO electroanatomical activation mapping. Two subgroups were created: centrifugal (CAT) or macroreentrant AT (MRAT). Total atrial activation time, CL, and mean bipolar signal amplitude (BiSA) were analysed. In Group I, 18 patients (51.4%) had CAT and 17 (48.6%) MRAT. The mean BiSA for Group I was 1.30 ± 0.32 mV. Total atrial activation time/CL ratios were different between CAT and MRAT (28.4 ± 16.9 vs. 66.6 ± 14.3%, P < 0.001). In Group II, 18 patients (50%) had CAT and 18 patients (50%) MRAT. The mean BiSA was 0.94 ± 0.50 mV and was not different for CAT and MRAT subgroups (1.04 ± 0.64 vs. 0.85 ± 0.29, P = 0.243). Total atrial activation time/CL ratios were comparable between CAT and MRAT patients (69.0 ± 40.4 vs. 83.6 ± 8.3%, P = 0.243). A significant lower BiSA was found for CAT with TAAT/CL ratios above 40% (0.62 ± 0.11 vs. 1.90 ± 0.18 mV, P < 0.001). A strong negative correlation was identified between the BiSA and the TAAT/CL ratio in patients with CAT in Group II (-0.742; P < 0.001). Low mean BiSA values in CHD patients are associated with altered impulse propagation, making TAAT- and CL-based diagnostic tools inaccurate. Further diagnostic tests are needed to determine the correct mechanism of ATs.

Electroanatomical mapping of the atrialized right ventricle: Placement of a transvenous implantable cardioverter-defibrillator in a patient with Ebstein’s anomaly

A 47-year-old woman with Ebstein’s anomaly suffered from an out-of-hospital cardiac arrest caused by ventricular fibrillation. Electroanatomical activation mapping showed an atrialized right ventricle. Atrial electrocardiogram, normal atrioventricular node conduction delay, and ventricular electrocardiogram were confirmed in the right atrium. Relatively preserved ventricular amplitude was found in the septal wall. Based on these findings, a transvenous dual-chamber implantable cardioverter-defibrillator was implanted for the prevention of sudden cardiac death. The patient has fared well, without any lead malfunctions, lead dislodgement, or inappropriate shocks. Sufficiently high atrial and ventricular amplitudes were confirmed during 18 months of follow-up.

Endocardial Electrogram Characteristics of Epicardial Ventricular Arrhythmias

While most ventricular arrhythmias (VA) can be ablated successfully using an endocardial (endo) approach, epicardial (epi) mapping and ablation is sometimes required. There may be suggestive clues on the surface electrocardiogram; however, identification of an epi origin of VA with certainty remains problematic. All patients referred for ablation of ventricular tachycardia or frequent ventricular ectopy from June 2007 to July 2011 were evaluated. Patients with completed endo and epi electroanatomical activation maps of an epi VA were included (n = 10). Bipolar electrograms (EGMs) in the area of earliest endo activation were analyzed and compared to the area of early epi activation. An EGM component was characterized as far field if it was monophasic and there was inability to capture. We identified 3 characteristics from endo mapping that consistently indicated need for epi ablation: (1) Diffusely early activation (>2 cm(2) region of sites with equally earliest activation within 10 milliseconds). (2) Sequence of a far-field EGM followed by a near-field EGM in the region of earliest endo activation. (3) Inability to capture the far-field component of the earliest EGM (stim-QRS < egm-QRS time) or reproduce morphological features of the VA complex with stimulation at the earliest endo site of activation. The presence of a diffusely early area of activation and inability to capture a far-field endo EGM indicates that epi ablation may be needed to eliminate a VA.

Intracardiac acoustic radiation force impulse imaging: a novel imaging method for intraprocedural evaluation of radiofrequency ablation lesions.

Arrhythmia recurrence after cardiac radiofrequency ablation (RFA) for atrial fibrillation has been linked to conduction through discontinuous lesion lines. Intraprocedural visualization and corrective ablation of lesion line discontinuities could decrease postprocedure atrial fibrillation recurrence. Intracardiac acoustic radiation force impulse (ARFI) imaging is a new imaging technique that visualizes RFA lesions by mapping the relative elasticity contrast between compliant-unablated and stiff RFA-treated myocardium. To determine whether intraprocedure ARFI images can identify RFA-treated myocardium in vivo. In 8 canines, an electroanatomical mapping-guided intracardiac echo catheter was used to acquire 2-dimensional ARFI images along right atrial ablation lines before and after RFA. ARFI images were acquired during diastole with the myocardium positioned at the ARFI focus (1.5 cm) and parallel to the intracardiac echo transducer for maximal and uniform energy delivery to the tissue. Three reviewers categorized each ARFI image as depicting no lesion, noncontiguous lesion, or contiguous lesion. For comparison, 3 separate reviewers confirmed RFA lesion presence and contiguity on the basis of functional conduction block at the imaging plane location on electroanatomical activation maps. Ten percent of ARFI images were discarded because of motion artifacts. Reviewers of the ARFI images detected RFA-treated sites with high sensitivity (95.7%) and specificity (91.5%). Reviewer identification of contiguous lesions had 75.3% specificity and 47.1% sensitivity. Intracardiac ARFI imaging was successful in identifying endocardial RFA treatment when specific imaging conditions were maintained. Further advances in ARFI imaging technology would facilitate a wider range of imaging opportunities for clinical lesion evaluation.

Displacement of the target ablation site and ventricles during premature ventricular contractions: Relevance for radiofrequency catheter ablation

During premature ventricular contractions (PVCs), a spatial displacement of the ventricles and the target ablation site with respect to the sinus rhythm (SR) position is observed during mapping and ablation. To analyze this displacement and its relevance for image integration and PVC ablation. The electroanatomical activation maps (EAMs) of 55 consecutive patients who underwent PVC ablation were analyzed. Spatial displacement between each point position during PVC and SR was obtained. A total of 6923 points from 71 EAMs were analyzed. Overall, the median distance between the point position during SR and PVC for all the points was 9.42 mm (interquartile range [IQR]: 6.19-12.85). The EAM points from the right ventricle showed more displacement than did those from the left ventricle: 10.35 mm (IQR: 7.16-13.95) vs 7.62 mm (IQR: 5.20-10.81); P <.001. The ventricular end-diastolic volume of the EAM during SR was greater than that during PVC (median difference: 9.75 [IQR: 0.37-19.67] mL; P = .002). A shorter coupling interval of the PVC was associated with greater spatial displacement (r = -.521; P <.001), higher end-diastolic volume reduction with respect to the SR beat (r = -.718; P = .001), and worse image integration (mean point-to-surface distance between EAM and 3-dimensional computed tomography-derived structure; r = -.642; P = .018). There is a significant spatial displacement between the point position in SR and PVC, mainly in the right ventricle. This displacement increases with the shortening of the PVC coupling interval and can result in poorer image fusion and difficult catheter navigation/positioning for ablation.

Abstract 9250: Endocardial Electrogram Characteristics Indicating an Epicardial Origin of Focal Ventricular Arrhythmias

Introduction: While most ventricular arrhythmias (VA) can be ablated successfully using an endocardial (ENDO) approach, epicardial (EPI) mapping and ablation is sometimes required. There may be clues on the surface electrocardiogram related to intrinsicoid deflection and QRS width; however, identification of an EPI origin of VA with certainty remains problematic, and there are no reported ENDO electrogram (EGM) characteristics that may direct ablation strategy. Methods: All patients referred for ablation of ventricular tachycardia or frequent ventricular ectopy from June 2006 through July 2010 were evaluated. Only patients with completed electroanatomical activation maps of a focal VA from ENDO and EPI were included. EGMs recorded by a bipolar mapping catheter in the area of earliest ENDO activation were analyzed and compared to the area of early EPI activation. Results: There were 17 patients with completed ENDO and EPI electroanatomical maps of a focal VA identified. We identified 3 characteristics from ENDO mapping that consistently indicated an EPI VA origin: 1) Diffusely early activation (&gt; 2cm2 region of sites with equally earliest activation within 10 msec; figure); 2) Sequence of a far-field EGM followed by a near-field EGM in the region of earliest ENDO activation; and 3) Inability to capture the far-field component of the earliest ENDO EGM (stimulus-QRS &lt; egm-QRS time) or reproduce the PVC or VT QRS complex morphology with pacing at the earliest ENDO activation site. Conclusions: The presence of a diffuse area of early activation and inability to capture a far-field electrogram from the endocardium indicates an epicardial origin of a focal ventricular arrhythmia.

Supraventricular Tachycardia After Atrial Fibrillation Ablation.

Atrial arrhythmias occur commonly after atrial fibrillation (AF) ablation. Initial conservative management with medical therapy and cardioversion is reasonable, particularly in the early period (first 3 months) after ablation, because many of these arrhythmias remit over time. However, definitive therapy with ablation may be required, depending on the clinical circumstances, and should focus on the putative mechanism of tachycardia and its likely location, both of which can be suggested by the initial AF ablation strategy. Response to pacing, entrainment, and electroanatomic activation mapping are useful to confirm the mechanism, define complex circuits, and guide ablation targets.

Two concomitant arrhythmias in a transplanted heart

A 61-year-old man was admitted to our center complaining from palpitations due to frequent supraventricular extrasystoles (SVES). The patient had received an orthotopic heart-transplantation in 1989 due to dilated cardiomyopathy. In 2005, isthmus-dependent typical atrial flutter was documented and successfully ablated. Before the current admission, a 3-day Holter ECG recording was done which showed 15,000 SVES per day. There had been no signs of rejection and the left ventricular ejection fraction was 65%. On the 12-lead surface ECG a sinus rhythm with frequent SVES was noted with a P wave morphology closely resembling the sinus rhythm. Since the patient was highly symptomatic, we decided to perform an invasive electrophysiological study and ablation [1–3]. The patient gave written informed consent for the procedure of electrophysiology study and catheter ablation. After femoral vascular access, a steerable decapolar (Inquiry , Irvine Biomedical, Inc., Irvine CA, USA) and a non-steerable quadripolar catheter (Supreme , St. Jude Medical Inc., St. Paul MN, USA) were placed in coronary sinus and right ventricular apex, respectively. Electroanatomical mapping of right atrium was done using a 4-mm tip ablation catheter (Navi-Star, Biosense-Webster, Diamond Bar CA, USA) and the CARTO XP system (BiosenseWebster, Diamond Bar CA, USA). The surface ECG and the coronary sinus catheter showed sinus rhythm with frequent SVES; however, mapping of the posterior (recipient) right atrium showed an organized atrial arrhythmia, most probably an atypical atrial flutter with a cycle length of 170 ms which was electrically disconnected from the rest of the donor atria (Fig. 1). In the border zone between electrically isolated recipient and donor atria, both sinus rhythm and atypical atrial flutter were recorded at the same time on the mapping catheter (Fig. 1). We did not perform the activation mapping of the atypical atrial flutter in the recipient right atrium. Due to similar P wave morphologies of sinus rhythm and SVES, we decided to perform electroanatomical activation mapping during the sinus rhythm and SVES (Fig. 1) which showed a close proximity of sinus node and the ectopic focus of SVES (10 mm). An ablation was then performed successfully at the ectopic focus during which the SVES ceased and the patient remained in stable sinus rhythm during the rest of the hospitalization. During the procedure we did not note any signs of electrical conduction between the recipient and the donor heart although this has previously been described [4, 5]. The most common arrhythmia 2in heart transplant recipients is sinus node dysfunction leading to pacemaker implantation. Vaseghi et al. [6] studied recently the incidence, clinical course, and management of supraventricular tachycardia in 729 orthotopic heart transplant patients. The most common arrhythmia, atrial flutter, occurred in 9% of this cohort. Persistent or paroxysmal atrial fibrillation occurred in 7%, 57% in the perioperative period. Persistent or paroxysmal atrial fibrillation beyond the postoperative period was observed only in the presence of rejection or transplant vasculopathy. Other persistent or paroxysmal supraventricular tachycardias were seen in 47 patients (7%). Of these, 24 patients underwent EPS. Accessory and dual atrioventricular nodal pathways in the donor heart caused SVT in 3 patients. Macro-reentrant atrial tachycardia was seen in 7 patients, and isthmus-dependent atrial flutter occurred in 14 patients. In conclusion, the majority of supraventricular tachycardias in stable orthotopic heart F. Frogner A. Arya (&) C. Piorkowski G. Hindricks Department of Electrophysiology, Heart Center, University of Leipzig, Strumpellstrasse 39, 04289 Leipzig, Germany e-mail: dr.arasharya@gmail.com

Is it possible to create a linear lesion with no local electrograms? Comparison between a three-dimensional mapping system and conventional fluoroscopy for cavotricuspid isthmus ablation of typical atrial flutter

The aim of this prospective, randomised study was to evaluate the efficacy, safety and long-term outcomes of the complete disappearance of local electrograms along the linear lesion using the EnSite NavX three-dimensional mapping system as compared with conventional fluoroscopy for ablation of typical atrial flutter (AFL). Seventy-three patients with spontaneous AFL episodes were randomised to undergo fluoroscopy-guided (group I, n=35) or EnSite NavX-guided (group II, n=38) ablation. When bidirectional isthmus block was achieved, the catheter was navigated back along the ablation line to assess the presence of local potentials along the lesion line. Bidirectional isthmus block was achieved in all patients. Mean total fluoroscopy time was 19.8 +/- 4.1 min in group I and 9.1 +/- 3.5 min in group II (P<0.001); mean fluoroscopy time required for radiofrequency ablation was 6.9 +/- 1.4 min in group I and 0.6 +/- 0.3 min in group II (P<0.001). During a follow-up of 16 +/- 9 months, three patients in group I (10%) experienced recurrence of AFL as opposed to none in group II (P<0.005). NavX technology allows accurate re-navigation of the lesion line to assess the presence of local potentials during an ablation procedure for typical AFL. Electroanatomic activation mapping can accurately identify gaps in the linear radiofrequency lesion with no AFL recurrence compared with 20% of recurrences after a standard procedure.