Left Atrial Macroreentrant Tachycardia Research Articles

AB-452674-1 HIGH-FREQUENCY ELECTROGRAM CHARACTERISTICS IN REGIONS OF LOW VOLTAGE ACCURATELY DISCRIMINATE SITES OF LEFT ATRIAL TACHYCARDIA TERMINATION

Localization of the critical isthmus of conduction of left atrial (LA) macroreentrant tachycardia (LAMRT) circuits within scar tissue is challenging (Panel A). Low voltage (LV) has been used as a marker for the arrhythmic substrate. However, voltage amplitudes due to near-field (NF) vs. far-field (FF) electrogram (EGM) components are not clearly differentiated. The peak frequency (PF) associated with bipolar EGM’s is a novel parameter which may distinguish them (Panel B). To compare the ability of LV vs. LV with high PF (LVHF) to discriminate the LAMRT termination region. Bipolar voltage and activation maps were generated with a 16-pole grid catheter (HD-Grid) during LAMRT (Panels A,B). PF maps were retrospectively computed (Panel C). LAMRT’s were only included if terminated by focal RF lesions (boundary <1.5cm diameter). The LA mapped surface was sub-regioned into the termination (T-ZONE) and non-termination (NT-ZONE) zones. The T-ZONE was centered about the termination site and allowed to extend to a rectangular kernel >0.5cm and <1.5cm across perpendicular axes. The NT-ZONE encompassed the remainder of the mapped surface area (SA). Sensitivity (SE) and specificity (SP) of T-ZONE vs. NT-ZONE discrimination was measured according to the %T-ZONE vs. %NT-ZONE SA occupied at LV thresholds (range 0.1-1.0mV) in 0.1mV increments (Panel E). LVHF at PF cutoffs of 150Hz (LVHF150), 200Hz (LVHF200), 250Hz (LVHF250) and 300Hz (LVHF300) were also assessed for TZONE discrimination (Panel F). 16 consecutive patients with 24 ATs were prospectively enrolled and 13 LAMRT’s were terminated by 2.85±2.82 focal RF lesions. The T-ZONE occupied 0.82±0.30cm2 (41±19 EGM points) vs. 158.6±42.2cm2 (2967±1227 points) for the NT-ZONE. T-ZONE voltage was significantly lower vs. the NT-ZONE (0.12±0.05mV vs. 0.60±0.28mV, P<0.001 respectively). T-ZONE PF was significantly higher than the NT-ZONE PF (345±76Hz vs. 255±34Hz, P<0.001). ROC discrimination of the T-ZONE resulted in AUC’s of 0.69- LV, 0.86- LVHF150, 0.88- LVHF200, 0.86- LVHF250 and 0.78- LVHF300. LVHF200 yielded the best improvement of AUC vs. LV unconstrained by high PF (19.1%)(Panel E). At a 0.2 mV cutoff, LVHF200 yielded a balanced SE/SP of 0.86/0.83 respectively vs. SE/SP of 0.90/0.54 for LV alone. During AT, systematic identification of EGM regions of high frequency within LV can significantly improve the specificity of discrimination of the site of AT termination.

Acute safety and efficacy outcome of pulmonary vein isolation using pulsed field ablation technology

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Pulsed field ablation (PFA) is a new technology for electrical isolation of pulmonary veins (PVI) using electroporation for irreversible cell death. First data imply a very low complication rate in terms of esophageal lesion, phrenic nerve palsy and pulmonary vein stenosis. We present our datas of our first patients concerning acute safety and efficacy. Method 38 patients with paroxysmal and persistent atrial fibrillation (AF) consecutively underwent PFA ablation including complete PVI of all pulmonary veins in all cases (including 14 redo cases ), mean age 68,3 year, and a mean ejection fraction of 56 %, mean CHADSVASC Score 3. 19 patients had paroxysmal AF, in 21 patients additional posterior wall isolation was performed. Additional anatomical and voltage characterization with CARTO was performed before and after ablation. Post ablation, all patients underwent endoscopic evaluation of the esophagus and all eligible patients were screened for silent cerebral lesions (SCL) using cerebral magnetic resonance imaging (MRI). All acute procedure data and complications were documented. Results In all 38 patients effective PVI using only PFA catheter was achieved (100 %) within a mean procedure time of 81±15 min and a mean fluoroscopy time of 18± 5 min. In 2 patients left atrial macroreentrant tachycardia was effectively terminated with PFA pulses in the PV-mitral-annular isthmus region. In no patient an esophageal lesion could be detected (0%). Cerebral MRI was performed in 18 cases and revealed SCLs (47 %) in 5 patients (3 patients with multiple lesions, 2 patiens with 3 lesions, max size of 8 mm). No symptomatic complications including pericardial effusion or access site complications were noted. Conclusion PFA is a highly effective method for acute PVI. No relevant symptomatic complications were noted. Of note, no patient had esophageal injury related to the ablation but 40% of patients undergoing post-ablation MRI had documented SCE. Further data have to be collected to discuss these findings properly.

Left atrial anterior line ablation using ablation index and inter-lesion distance measurement.

Ablation index (AI) is a novel ablation quality marker that incorporates contact force (CF), time and power in a weighted formula to provide accurate information about lesion formation during catheter ablation. This index has been evaluated for pulmonary vein isolation (PVI) but has not been systematically used for other left atrial (LA) procedures so far. The aim of this study is to evaluate the feasibility and efficacy of this index for LA anterior line (AL) ablation (LAALA). 30 consecutive patients with persistent atrial fibrillation or LA macro-reentrant tachycardia and large low-voltage area at the left atrial anterior wall were evaluated and divided into 2 groups: group 1 (15 pts) LAALA guided by CF; group 2 (15 pts) LAALA guided by AI target (500) and inter-lesion distance ≤ 6mm. In group 2, shorter ablation time (12.5 ± 3.8 vs 17 ± 7min, p = 0.049), overall RF application time (7.9 ± 1.4 vs 10.8 ± 3.2min. p = 0.01) and less radiofrequency (RF) applications (14.5 ± 2.3 vs 20.5 ± 6.1 p = 0.01) were necessary to achieve AL bi-directional block. Acute reconnection of the AL was documented in three patients (20%) of group 1 and in no patient of group 2 (20% vs 0% p = 0.22). At site of reconnection, an inter-lesion distance > 6mm was always found. There was no difference in terms of CF and power between group 2 and group 1. AI was statistically different between group 2 and group 1 (AI = 511 ± 77 vs 451 ± 111; p = 0.004). AI-guided LAALA in this study was feasible and featured by shorter ablation time, shorter overall RF application time and a reduced number of RF applications to achieve AL bidirectional block.

Mapping and ablation of a left atrial macro reentrant tachycardia originating from the left superior pulmonary vein

Mapping and ablation of a left atrial macro reentrant tachycardia originating from the left superior pulmonary vein

Regular atrial tachycardias developing after cryoballoon pulmonary vein isolation: incidence, characteristics, and predictors

Cryoballoon ablation (CBA) is a well-used technique when performing pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (AF). Our aim is to describe incidence, characteristics, and clinical predictors for developing atrial tachycardias (ATs) after cryoballoon PV isolation in patients with paroxysmal AF. The study population consisted of 181 consecutive patients undergoing a first CBA. All patients received an event-recorder before cryoablation and transmitted daily electrocardiogram (ECG) during 1 month before ablation and 3 months after. Further follow-up consisted of 24 h Holter monitoring and ECG registration every 3 months and also in patients presenting with symptoms. A mean follow-up period was 497.9 ± 283.9 days, and 175 patients completed follow-up. In 14 (8%) patients regular ATs were registered. In multivariate logistic regression model, the following parameters were independently associated with ATs after ablation: an additional right PV, treatment with beta-blockers, and presence of AT on event-recording strips before ablation. Seven (4%) patients with registered AT underwent a redo procedure. In two (1.1%) patients ATs were originated in reconnected PVs. In other patients no left AT was induced. No macro re-entrant left AT was documented in any patient. During follow-up, after a redo ablation, no AT was registered. The incidence of left AT after CBA is low, and no left atrial macro re-entrant tachycardia was found. The following independent predictors of AT development have been identified: an additional right PV, regular AT registered before ablation, and the use of beta-blockers.

Electroanatomic Characterization and Ablation Outcome of Nonlesion Related Left Atrial Macroreentrant Tachycardia in Patients Without Obvious Structural Heart Disease

Descriptions for left atrial macroreentry tachycardia (LAMRT) in patients without obvious structural heart disease or previous surgery or catheter radiofrequency (RF) ablation have been sparse. Ten of 226 patients (7 women, mean age 57 ± 14) with LAMRT underwent electroanatomic mapping and catheter ablation. None of the 10 patients had structural heart disease or history of previous surgery or catheter ablation. In all patients, the reentry circuits were located within a large low-voltage (bipolar voltage ≤ 0.5 mV) area in left atrium (LA), which contained 2.6 ± 1.2 electrically silent areas (ESAs) and/or lines of double potentials (LDPs). The tachycardia circuit propagated through a narrow isthmus (<5 mm width) bounded by ESAs/LDPs and adjacent anatomical barriers (e.g., mitral annulus). In these isthmus, low amplitude (0.21 ± 0.05 mV), long-duration (123 ± 14 milliseconds) fractionated electrograms were found in 8 tachycardias, accounting for 43 ± 5% of the tachycardia cycle length. In 2 other tachycardias without fractionated electrograms, the electrogram amplitude in the isthmus was extremely low (<0.1 mV). RF energy was delivered at the isthmuses and terminated all 10 tachycardias. After ablation, the original LAMRT was not inducible in all patients. During follow-up (mean 14 ± 10 months), 2 patients developed recurrence of ATs and were successfully ablated. Extensive scarring of the LA formed arrhythmogenic substrates of LAMRT in this group of patients. Ablation targeting these narrow, slow conduction zones eliminated atrial tachycardia in all patients.

Recovery of Mitral Isthmus Conduction Leads to the Development of Macro-Reentrant Tachycardia After Left Atrial Linear Ablation for Atrial Fibrillation

Left atrial linear ablation for atrial fibrillation (AF) may be proarrhythmic, leading to left atrial macro-reentrant tachycardia (LAT). Whether due to failure to achieve block initially or to recovery of conduction after ablation is unknown. This study was designed to evaluate the frequency of recovery of mitral isthmus (MI) conduction compared with cavo-tricuspid isthmus (CTI) conduction, and the relationship between recovery of MI conduction and postablation LAT. Of 163 patients with AF who underwent circumferential pulmonary vein ablation plus left atrial linear ablation, in whom MI and CTI ablation produced bidirectional conduction block, 52 underwent repeat ablation for recurrent atrial arrhythmias (AF or LAT). Of these 52 patients, coronary sinus ablation was required in 48 to achieve bidirectional MI block at the index ablation. During repeat ablation, MI and CTI conduction was assessed in sinus rhythm. At repeat ablation, MI conduction had recovered in 38 of 52 patients, as compared with CTI conduction which recovered in only 12 of 52 patients (P=0.001). At repeat ablation, the recurrent clinical arrhythmia in 12 patients was MI-dependent LAT. Recovery of MI conduction was associated with development of MI-dependent LAT (P=0.01). Despite using bidirectional conduction block as a procedural end point, recovery of MI conduction is common and may lead to LAT after left atrial linear ablation for AF. The reason for greater recovery of MI versus CTI conduction is unknown but could be due to differences in isthmus anatomy or lower power used for ablation in the left versus right atrium.

Color-coded three-dimensional entrainment mapping for analysis and treatment of atrial macroreentrant tachycardia

Mapping and ablation of atrial macroreentrant tachycardia focus on activation mapping with identification of the area of slow conduction. The purpose of this study was to evaluate a new concept for analysis and treatment of macroreentrant tachycardia based on color-coded three-dimensional (3D) entrainment mapping and subsequent placement of strategic lesion lines. Twenty-six patients presented with macroreentrant tachycardia (cycle length 329 +/- 70 ms). Using nonfluoroscopic systems (CARTO 12, NavX 14), sequential mapping of the target atrium was performed. On each mapping point, the 3D location was paired with color-coded entrainment information so that the reentrant circuit could be directly visualized. Procedural duration, fluoroscopy time, and radiofrequency time measured 181 +/- 58, 37 +/- 19, and 31 +/- 17 minutes, respectively. Thirty-nine macroreentrant tachycardias were ablated: perimitral 9, around pulmonary vein ostium 6, through left atrial roof 5, around left atrial appendage 3, right atrial cavotricuspid isthmus dependent 6, around right atrial scar 2, around superior vena cava 1, within the septum 5, and within the coronary sinus 2. Tachycardia termination and noninducibility of any macroreentrant tachycardia was the procedural end-point. In case of left atrial macroreentrant tachycardia, pulmonary vein isolation was completed. Follow-up with serial 7-day Holter covered 302 +/- 82 days. Two (8%) patients experienced recurrences of a pretreated macroreentrant tachycardia. In patients with macroreentrant tachycardia, color-coded 3D entrainment mapping is feasible to accurately determine and visualize the 3D location of the reentrant circuit and to plan a strategic ablation line concept. That approach, not targeting the area of slow conduction of the circuit, resulted in excellent procedural success (100%), with long-term freedom from any tachycardia recurrences in 88% of patients.

Pulmonary Vein Conduction Is the Major Finding in Patients with Atrial Tachyarrhythmias after Intraoperative Maze Ablation

Electrophysiological (EP) data from patients with recurrent atrial tachyarrhythmias (ATa) after intraoperative maze ablation are limited. Furthermore, the clinical course after accomplishing pulmonary vein (PV) isolation using the double lasso technique (DLT) is unknown. EP study and catheter ablation (CA) was guided by a three-dimensional electroanatomic mapping system (3-D EA, CARTO, Biosense-Webster) combined with simultaneous ipsilateral PV mapping using the DLT. Defined endpoints were: (1) identification of conduction gaps within the ipsilateral PVs, (2) elimination of all PV spikes, and (3) ablation of clinical ATas. CA was performed in eight patients (four females, 62 +/- 5 years, LA: 50 +/- 6 mm) with drug refractory ATa (9.1 +/- 6.3 years) despite non-"cut and sew" maze operation. Electrical PV conduction was demonstrated in the majority of patients (7/8). All endpoints were achieved. Repeat ablations were required in three patients. Second ablation was due to typical atrial flutter (n = 1) and atrial fibrillation (n = 2). One patient required three ablations due to a left atrial macroreentrant tachycardia. During a mean follow-up of 15.5 +/- 4.8 months, 7/8 patients were free of ATa recurrences. Incomplete lesions after non-"cut and sew" maze operation are associated with PV conduction and recurrence of ATas. Electrical isolation of ipsilateral PVs and completion of linear lesions guided by 3-D EA mapping is feasible and successful in maintaining sinus rhythm during mid term follow-up. Completeness of linear lesions using EP endpoints should be confirmed during the initial surgical procedure to minimize ATa recurrences.

A case of left atrial macro-reentrant tachycardia involving the myocardium of the coronary sinus.

A case of left atrial macro-reentrant tachycardia involving the myocardium of the coronary sinus.

Caracterización electrofisiológica y clínica de la taquicardia macrorreentrante auricular izquierda

We are reporting the characteristics of 9 patients with left atrial macroreentrant tachycardia, an arrhythmia not well studied in man. Mean age was 60 years and 7 were men. Tachycardia was spontaneous in 6 and induced in 3. Two had no heart disease, 2 sick sinus syndrome, 3 aortic prosthesis, 2 hypertension, 1 cardiomyopathy and 1 chronic bronchitis. Simultaneous recordings from right atrial, coronary sinus and right pulmonary artery were obtained at baseline and with atrial pacing. Macroreentrant tachycardia was diagnosed when entrainment with fusion was documented. Cycle length was 230-440 ms (287 67). The ECG showed atypical flutter in 3 patients and P waves with flat baseline in 6. Coronary sinus activation was distal to proximal in 7. Right atrial activation was circular in 3 with previous typical flutter ablation. Entrainment from the right atrium produced long return cycles in the right atrial recordings, but equal to basal tachycardic cycle in coronary sinus recordings. Entrainment from the coronary sinus produced local return cycles equal to basal cycle in 8 and prolonged in 1. After stimulation, 4 recovered sinus rhythm, 4 went to atrial fibrillation and 1 had no change. After a follow-up of 9-19 months 5 remain in sinus rhythm treated with antiarrhythmic drugs and/or atrial pacing. Left atrial macroreentrant tachycardia is associated with organic heart disease. The ECG most frequent pattern tends to show P waves with flat baseline at a relatively slow rate. Most circuits turn clockwise in anterior view. Atrial stimulation is not very effective for cardioversion to sinus rhythm. The prognosis of long term rhythm is uncertain.