Left Voltage Research Articles

The impact of an empiric superior vena cava isolation added to pulmonary vein isolation for non-paroxysmal atrial fibrillation associated with left atrial low voltage areas

Abstract Introduction Left atrial low-voltage areas (LVAs) are associated with recurrence after radiofrequency catheter ablation of atrial fibrillation (AF). However, the impact of LVAs on recurrence after an empiric pulmonary vein isolation (PVI) plus superior vena cava isolation (SVCI) strategy for non-Paroxysmal AF (PAF) patients remains unclear. Purpose We evaluated the impact of LVAs on the recurrence of atrial tachyarrhythmias (ATs)/AF in patients who underwent an empiric SVCI added to the PVI for non-PAF. Methods We enrolled 153 consecutive patients with non-PAF who underwent a PVI alone (PVI group; n=51) or empiric PVI plus SVCI (PVI+SVCI group; n=102). Left atrial voltage maps were constructed during sinus rhythm to identify the LVAs (<0.5 mV). No patients underwent a substrate modification of the LVAs. We divided the patients into two groups based on the LVAs (with or without an LVA >5% of the left atrial surface area) and investigated the ATs/AF free survival rate after the initial and multiple procedures. Results LVAs were identified in 65% and 73% of the PVI and PVI + SVCI groups, respectively (P=0.319). In the PVI group, the 18-month ATs/AF-free survival was 61% of the patients without LVAs and 27% of patients with LVAs after the initial session (P=0.018) (Figure 1-A). Seventy-two percent of the patients without LVAs and 46% of those with LVAs were free from ATs/AF after multiple sessions (P=0.083) (Figure 1-B). In the PVI+SVCI group, 50% of the patients with LVAs and 61% of those without LVAs had no recurrence after the initial session (P=0.374) (Figure 2-A). Moreover, there was no significant difference in the 18-month ATs/AF-free survival between the patients with and without LVAs after multiple sessions (73% vs. 79%; P=0.520) (Figure 2-B). Conclusion A PVI alone strategy for non-PAF patients with LVAs had limited efficacy for the outcomes, even with multiple procedures. However, an SVCI may have the potential to compensate for an impaired outcome in patients with LVAs. Funding Acknowledgement Type of funding source: None

Pre-ablation left atrial function predicts the presence of low voltage zone in patients undergoing paroxysmal atrial fibrillation ablation: OLAF-LVZ predictive score

Abstract Background Preoperative left atrial (LA) function is associated with paroxysmal atrial fibrillation (PAF) ablation outcome. The presence of left atrial low voltage zone (LVZ) is also associated with recurrence. We hypothesized that reduced pre-ablation LA function reflects the presence of LVZ. Purpose We investigated the association between baseline LA function and the presence of LVZ in patients undergoing initial PAF ablation. Further, we sought to create the new predictive scoring for the presence of LVZ. Methods Consecutive 305 patients who underwent LA voltage mapping during initial PAF ablation from January 2017 to October 2019 in our institute were retrospectively analyzed. We performed 256-slice MDCT at baseline. As the representative of LA function, we calculated LA emptying fraction (LAEF), where LAEF = {[(maximum LAV) − (minimum LAV)]/(maximum LAV)} x 100. LVZ was defined as regions where bipolar peak-to-peak voltage was <0.5mV. We performed the univariate and multivariate analysis to assess the association between LAEF and the presence of LVZ. Second, we performed receiver operating characteristic (ROC) analysis for the prediction of LVZ. We combined multivariate predictors and created the predictive scoring for LVZ. Results Out of 305 pts, 56 pts (18%) had LVZ in LA. In univariate analysis, low body mass index, higher percentage of female sex, higher age, higher E/e', larger maximum LA volume and lower LAEF (29.3±11.8% vs. 41.2±9.7, P<0.0001) was associated with the presence of LVZ. In multivariate logistic regression analysis, Low LAEF revealed the strongest predictor for LVZ (LAEF; Odds ratio [OR]/10% increase: 0.54, 95% CI: 0.39–0.82, P=0.0016). High age and female sex also remained as the independent predictors (Age; OR/10 y.o. increase: 1.80, 1.23–3.03, P=0.0042, Female; OR: 2.51, 1.15–5.49, P=0.0213). In ROC analysis, LAEF had moderate predictive accuracy for the presence of LVZ. (Area under the ROC curve: 0.77, Best cut-off value: 31%, P<0.0001) (Figure 1). We created OLAF-LVZ predictive score by combining Old age (1 point, ≥65), LAEF (2 points, LAEF ≤31%) and Female sex (1 point). OLAF score had gradient effect on the incidence of LVZ (2%, 11%, 25%, 45%, 71%, OLAF score; 0, 1, 2, 3, 4, respectively, P<0.0001) (Figure 2). Conclusions In PAF patients, preoperative LAEF was strongly associated with the presence of LVZ. LVZ might reflect the myocardial injury causing LA dysfunction. OLAF-LVZ predictive score: combination of Old age (≥65), Female sex, and LAEF (≤31%) could be useful to stratify the risk of the presence of LVZ. Funding Acknowledgement Type of funding source: None

Mechanisms of long-term recurrence three years after catheter ablation of atrial fibrillation

Abstract Background AF is a progressive disease, and the mechanism underlying long-term recurrence after AFCA is unclear. Purpose This study explored the potential mechanisms of long-term recurrence (LTR) of atrial fibrillation (AF) 3-years after AF catheter ablation (AFCA). Methods Among 2,209 consecutive patients who underwent AFCA, 1,325 (59±11 years, 72.5% male) who underwent regular rhythm follow-ups for >3-years were enrolled. Among them, 659 patients remained in sinus rhythm (SR), 327 recurred after 3–12 months (short-term recurrence; STR), 235 after 1–3 years (mid-term recurrence; MTR), and 104 after 3-years (long-term recurrence; LTR). Two hundred eighteen recurrent patients underwent repeat procedures: 112, 80, and 26 in the STR, MTR, and LTR groups, respectively. Results The pre-ablation left atrial (LA) dimensions were larger in the STR (p<0.001) and MTR groups (p<0.001), but not in the LTR group compared to the SR group. Low LA voltages were independently associated with an LTR (adjusted HR 0.57 [0.36–0.92], p=0.022). Upon the redo-mapping, the number of reconnected pulmonary veins (PVs) was 2.0 (IQR 0–3), 1.5 (IQR 0–3), and 1.0 (IQR 0–2) in the STR, MTR, and LTR groups, respectively (p=0.030). Post-ablation extra-PV triggers were more commonly found in the LTR than STR or MTR groups (LTR 40.9% to STR 19.2%, p=0.014) during the second procedure. Conclusions The LTR group had a similar baseline LA size and significantly lower LA voltage than the SR group. In the repeat procedures, the LTR group had fewer reconnected PVs, but extra-PV triggers were more common than in the STR and MTR groups. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Ministry of Health and Welfare, Ministry of Science, ICT & Future Planning (MSIP).

Relationship between left atrial strain and left atrial bipolar voltage in patients undergoing catheter ablation for atrial fibrillation

Abstract Background Low-voltage zone (LVZ) in the left atrium (LA) seems to represent fibrosis. LA longitudinal strain assessed by speckle tracking method is known to correlate with the extent of fibrosis in patients with mitral valve disease. Purpose We sought to identify the relationship between LA longitudinal strain and LA bipolar voltage in patients with atrial fibrillation (AF). We tested the hypothesis that LA strain can predict LA bipolar voltage. Methods A total of 96 consecutive patients undergoing initial AF ablation were analyzed. All patients underwent transthoracic echocardiography including 2D speckle tracking measurement on the day before ablation during sinus rhythm (SR group, N=54) or during AF (AF group, N=42). LA longitudinal strain was measured at basal, mid, and roof level of septal, lateral, anterior, and inferior wall in apical 4- and 2-chamber view. Global longitudinal strain (GLS) was defined as an average value of the 12 segments. LA voltage map was created using EnSite system, and global mean voltage was defined as a mean of bipolar voltage of the whole LA excluding pulmonary veins and left atrial appendage. LVZ was defined as less than 1.0 mV. Results There was a significantly positive correlation between GLS and global mean voltage (r=0.708, p<0.001). Multivariate regression analysis showed that GLS and age were independent predictors of global mean voltage. There was a significant negative correlation between global mean voltage and LVZ areas. Conclusions There was a strong correlation between LA longitudinal strain and LA mean voltage. GLS can independently predict LA mean voltage, subsequently LVZ areas in patients with AF. Funding Acknowledgement Type of funding source: None

Quantitative analysis of the isolation area after larger-size laser balloon ablation

Abstract Background The visually guided laser balloon ablation is a balloon-based catheter ablation technology used for atrial fibrillation (AF) ablation in recent years. This balloon catheter consists of a compliant balloon that has the capability of real-time endoscopic visualization of the targeted pulmonary vein (PV). The sizeable balloon is usually inflated to obtain optimal PV occlusion. The isolation area after laser balloon (LB) ablation was reported to be smaller than that after cryoballoon ablation. However, when LB is inflated with its maximum pressure, it can visualize wide-area PV antrum. Thereby, we suspected that larger-size LB can create wider isolation area. Purpose The aim of this study is to quantitatively evaluate the isolation area after LB ablation at the size larger than appropriate size for ablation in the pulmonary vein carina region. Methods We assessed 66 patients with AF who underwent LB ablation at the larger inflation size in our hospital during the period from July 2018 to July 2019. After LB ablation, we created voltage maps with a circular mapping catheter and calculated isolation areas with CARTO system. Results Figure shows a larger LB with its maximum pressure. PV antrum isolation was extended to the posterior wall in all patients. The left- and right-sided pulmonary vein antrum isolation area were 15.1±3.9 and 19.4±4.3 cm2, respectively. Conclusion LB at the larger inflation size with its maximum pressure can isolate wider-area circumferential PV antrum than previously reported. This method may be a new way of pulmonary vein antrum isolation. Left atrial voltage mapping after PVI. Funding Acknowledgement Type of funding source: None

Reduction of mapping time in pulmonary vein isolation using atrial pacing during left atrial voltage map acquisition

Introduction3D mapping systems are used during radiofrequency (RF) pulmonary vein isolation (PVI) to facilitate catheter navigation and to provide additional electroanatomical information as a surrogate marker for the presence and location of fibrotic atrial myocardium.Electric voltage information can only be measured when the myocardium is depolarized. Low heart rates or frequent premature atrial beats can significantly prolong creation of detailed left atrial voltage maps. This study was designed to evaluate the potential advantage of voltage information collection during atrial pacing instead of acquisition during sinus rhythm. Methods and resultsA total of 40 patients were included in the study, in 20 consecutive patients voltage mapping was performed during sinus rhythm, and in the following 20 patients during atrial pacing. The average age of the included patients was 69.5 ± 9.4, 17 of 40 patients (43%) were male.All procedures were performed using the Carto 3D Mapping system. For LA voltage mapping, a multipolar circular mapping catheter was used. The atrium was paced via the proximal coronary sinus catheter electrodes with a fixed cycle length of 600 ms.By mapping during atrial pacing mapping time was reduced by 35% (441 s. (±141) vs.683 s. (±203) p = 0.029) while a higher number of total mapping points were acquired (908 ± 560 vs. 581 ± 150, p = 0.008). ConclusionAcquiring left atrial low voltage maps during atrial pacing significantly reduces mapping time. As pacing also improves comparability of left atrial electroanatomical maps we suggest that this approach may be considered as a standard during these procedures.

Distribution and area of low voltage and dense scar zones and their relation to left atrial enlargement in ablation-naïve patients with paroxysmal atrial fibrillation

There is paucity of studies correlating the left atrial (LA) dilation and the LA total and abnormal voltage areas in patients with atrial fi brillation (AF). We sought to determine the area of LA and its segments by high-density mapping in patients with paroxysmal AF, and to correlate the LA dilation defi ned by echocardiography with the total and the abnormal LA areas. Material and Methods. Retrospective study of patients with paroxysmal AF and pulmonary vein isolation proceeded by high-density mapping in sinus rhythm. All had transthoracic echocardiography and LA dilation, if present, was graded as mild/moderate-severe. LA voltage was defi ned as low (< 0.5 mV) or scar (< 0.1 mV). The LA was divided in 5 segments and the total and segmental area, low voltage area and scar area were measured. Data were presented as mean ± SD or median and interquartile interval (25-75%) depending on normality of distribution. Shapiro-Wilk test, Spearman T correlation, Kruskal-Wallis, and ANOVA analysis were used. A p-value < 0.05 was considered significant. Results. Sixty-seven patients (66% males) were studied. LA enlargement was present in 58% (mild enlargement in 39%, moderate/severe in 19%). Low voltage and scar areas were found in both groups with and without LA dilation. Moderate correlation was found between the percentage of abnormal area and the degree of LA dilation (none vs mild vs moderate/severe), rho = 0.44, p = 0.0002. In patients with non-dilated LA the mean total LA area was 100.4 ± 17 cm2 and the abnormal area was < 10% (9.9%, 6.2-14.8%), with barely detectable scar. In patients with LA enlargement the total area was approximately 10% larger (109.8 cm2, 100.9-123.8 cm2), however the abnormal area was almost doubled (17.1%, 11.1-26.8%), and there were small yet measurable dense scar areas. Conclusions. Low voltage LA areas < 0.5 mV were found universally by high-density mapping in patients with paroxysmal AF, irrespective of the presence of LA enlargement. However, only patients with LA enlargement had measurable scar areas. The total abnormal area correlated moderately with the degree of LA dilation defi ned by echocardiography.

Voltage-guided ablation in persistent atrial fibrillation-favorable 1-year outcome and predictors.

Pulmonary vein isolation (PVI) in persistent atrial fibrillation (AF) has a low success rate. A newer ablation concept targets left atrial (LA) low voltage zones (LVZ) which correlate with fibrosis and predict recurrence after PVI. We aimed to determine the success of combined PVI- and LVZ-guided ablation and to identify the predictors for LVZ and for ablation success. A total of 119 consecutive patients who underwent their first ablation procedure due to persistent AF were included. After acquisition of a high-resolution LA voltage map, PVI- and LVZ-guided ablation were performed. Mean age was 69 ± 8 years, 53% were men, and 8% had longstanding persistent AF. We found LVZ in 55% of patients. Twelve-month freedom from recurrences off drugs was 69%. The only independent predictor for recurrence was the existence of LVZ (OR 4.2, 95% CI 1.54-11.41, p = 0.005). Existence of LVZ was predicted positively by age ≥ 67 years (OR 4.4, 95% CI 1.4-13.7, p = 0.011), LA volume index ≥ 68 ml/m2 (OR 3.9, 95% CI 1.4-10.5, p = 0.008), and GFR ≤ 85 ml/min/1.73 m2 (OR 12.5, 95% CI 2.0-76.6, p = 0.006). BMI ≥ 26 kg/m2 (OR 0.06, 95% CI 0.01-0.30, p = 0.001) was a negative predictor of LVZ. LVZ-guided ablation in combination with PVI results in comparably high success rates. However, the existence of LVZ remains the strongest predictor of ablation success.

Left Atrial Electroanatomical Voltage Mapping to Characterize Substrate and Guide Ablation

Despite enthusiasm for catheter ablation of atrial fibrillation, procedural outcomes are less robust when compared to other atrial arrhythmias Adverse atrial remodeling is associated with both the perpetuation of atrial fibrillation as well as decreased responsiveness to restorative therapies. However, characterization of remodeling has historically relied on demographic factors and echocardiographic imaging which provide inadequate insight into the pattern and distribution of atrial fibrosis. Advancements in electroanatomical mapping allow rapid collection of dense three-dimensional maps that display both structural and functional datasets. The purpose of this review is to discuss contemporary studies that seek to determine bipolar electrogram characteristics in patients with and without atrial fibrillation. We will also review studies that use electrogram data to guide substrate-based ablation in AF patients.

Catheter ablation of atrial arrhythmias in patients after thoracoscopic ablation of persistent atrial fibrillation

Aim. To determine the mechanisms of development and approaches to interventional treatment of postoperative atrial tachycardia in patients after thoracoscopic ablation (TA) of atrial fibrillation (AF). Material and methods . The results of thoracoscopic ablation of AF in 46 patients were analyzed, of which 19,5% (n=9) had atrial tachycardia after the procedure. Radiofrequency ablation (RFA) was conducted in these patients after a 3-month blanking period. Regardless of tachycardia type, the threedimensional reconstruction including high-density right and left atrial (LA) voltage mapping was performed in order to visualize the lesions, pulmonary veins and LA posterior wall isolations. After RFA and sinus rhythm restoration, re-mapping was performed to assess conduction block and absence of electrical activity in the lesion zones. Results. Complete pulmonary vein (PV) isolation was verified in 55,5% of patients (n=5). In 44,4% (n=4), there were residual PV fractionated potentials without conduction with LA. In 22,2% of subjects (n=2), we identified typical atrial flutter (AFL), which was terminated by RFA in cavotricuspid isthmus (CTI). There were 77,7% (n=7) of patients who were diagnosed with atypical LA flutter; 66,6% (n=6) of them had conduction reconnection at the thoracoscopic box-lesion line. Perimitral AFL with slow conduction zone which was located on the anterior wall of LA was verified in 11,1% of patients (n=1). The effective RFA was performed in these areas. Two main factors affecting failed ablation were LA volume and body mass index (BMI). In patients with arrhythmias after TA, LA volume was 180,2±35,6 ml vs 158,34±38,5 ml in patients with sinus rhythm. BMI was 30,8±3,1 kg/m2 and 28,9±3,9 kg/m2, respectively. The mean follow-up was 9,8±2,7 months. All patients after catheter ablation maintained a stable sinus rhythm. Conclusion. Atrial tachycardia after TA is caused by the gaps in box-lesion lines. The main predictors of gaps are high values of LA volume and BMI. The high-density mapping increases the effectiveness of RFA. Combination of epicardial and endocardial accesses is the most effective approach to treatment of patients with persistent AF.

Mechanisms of Long-Term Recurrence 3 Years After Catheter Ablation of Atrial Fibrillation.

This study explored the potential mechanisms of long-term recurrence (LTR) of atrial fibrillation (AF) 3 years after AF catheter ablation (AFCA). AF is a progressive disease, and the mechanism underlying long-term recurrence after AFCA is unclear. Among 2,209 consecutive patients who underwent AFCA, 1,325 (age 59 ± 11 years, 72.5% male) who underwent regular rhythm follow-ups for >3 years were enrolled. Among them, 659 patients remained in sinus rhythm (SR), 327 recurred after 3 to 12months (short-term recurrence [STR]), 235 after 1 to 3 years (mid-term recurrence [MTR]), and 104 after 3 years (long-term recurrence [LTR]). Two hundred-eighteen recurrent patients underwent repeat procedures: 112, 80, and 26 in the STR, MTR, and LTR groups, respectively. The pre-ablation left-atrial (LA) dimensions were larger in the STR (p<0.001) and MTR groups (p<0.001) but not in the LTR group compared with the SR group. Low LA voltages were independently associated with an LTR (adjusted hazard ratio [HR]: 0.57 [0.36 to 0.92]; p=0.022). Upon the redo mapping, the number of reconnected pulmonary veins (PVs) was 2.0 (interquartile range [IQR]: 0 to 3), 1.5 (IQR: 0 to 3), and 1.0 (IQR: 0 to 2) in the STR, MTR, and LTR groups, respectively (p=0.030). Post-ablation extra PV triggers were more commonly found in the LTR than STR or MTR groups (LTR 40.9% to STR 19.2%; p=0.014) during the second procedure. The LTR group had a similar baseline LA size and significantly lower LA voltage than the SR group.Inthe repeat procedures, the LTR group had fewer reconnected PVs, but extra PV triggers were more commonthanintheSTR and MTR groups.

Clinical outcome of pulmonary vein isolation alone ablation strategy using VISITAG SURPOINT in nonparoxysmal atrial fibrillation.

Recent studies have shown the improvement in long-term effectiveness with standardized pulmonary vein isolation (PVI) aimed at creating durable and contiguous lesions with VISITAG SURPOINT (VS) in paroxysmal atrial fibrillation (PAF). We aimed to assess efficacy of PVI alone strategy using VS in non-PAF patients and evaluate factors associated with corresponding clinical outcomes. Consecutive patients who underwent PVI for persistent/long-standing persistent AF between May 2017 to July 2019 were studied retrospectively. PVI was performed with 30-50 W guided by VS (posterior target: 400-500, anterior target: 500). Left atrial voltage maps were created during atrial pacing after PVI. A total of 140 patients (119 males, age 62 ± 10 years, long-standing persistent AF: 35) were included and followed for median of 454 days. No adverse events were reported in any patients during periprocedural and follow-up period of up to 28 months. Kaplan-Meier analysis estimated that freedom from atrial tachycardia or AF (AT/AF) without antiarrhythmics at 1-year was 70%. Radiofrequency delivery with higher power was associated with increased first-pass isolation rate, but not with freedom from AT/AF. In multivariate analysis, long-standing persistent AF and % low-voltage zone (%LVZ) were independent predictors of clinical outcome. The best cut-off value of %LVZ for predicting AT/AF recurrence was 3.24%. Freedom from AT/AF was 88% in patients with persistent AF and %LVZ < 3.24%, while 27% in those with long-standing persistent AF and %LVZ ≥ 3.24%. PVI alone using VS was associated with excellent 1-year success in patients with persistent AF and %LVZ < 3.24%, but was insufficient in those with long-standing persistent AF and/or %LVZ ≥ 3.24%.

The feasibility and effectiveness of a streamlined single-catheter approach for radiofrequency atrial fibrillation ablation.

BackgroundCatheter ablation for atrial fibrillation (AF) traditionally requires the use of circular mapping catheter (CMC) for pulmonary vein isolation (PVI). This study aimed to assess the feasibility and effectiveness of a CMC‐free approach for AF ablation performed by a contiguous optimized (CLOSE) ablation protocol.MethodsA CLOSE‐guided and CMC‐free PVI protocol with a single transseptal puncture was attempted in 67 patients with AF. Left atrial (LA) CARTO voltage mapping was performed with the ablation catheter pre‐ and postablation to demonstrate entry block into the pulmonary veins, and pacing maneuvers were used to confirm exit block.ResultsThe CMC‐free approach was successful in achieving PVI in 66 (98.5%) cases, with procedure time of 148 ± 32 minutes, ablation time of 27.5 ± 5.7 minutes, and fluoroscopy time of 7.8 ± 1.0 minutes. First‐pass PVI was seen in 58(86.5%) patients, and pacing maneuvers successfully identified the residual gap in eight of the other nine cases. No complication was observed. At 12 months follow‐up, 60 (89.6%) patients remained free from AF. The CMC‐free approach resulted in a cost saving of £47,190.ConclusionA CMC‐free CLOSE‐guided PVI approach is feasible, safe, and cost‐saving, and is associated with excellent clinical outcomes at 1 year.

Osteopontin induces atrial fibrosis by activating Akt/GSK-3β/β-catenin pathway and suppressing autophagy

AimsAtrial fibrosis is a common feature of atrial fibrillation (AF). Recently, it is reported that osteopontin (OPN) can induce fibrosis in lungs, livers and kidneys. However, its role in atrial fibrosis remains unclear. Here, we sought to determine the involvement of OPN in atrial fibrosis and the underlying mechanisms during this pathological remodeling process. Materials and methodsProtein expressions were determined by enzyme-linked immunosorbent assay (ELISA), immunohistochemical staining and immunoblotting. mRNA expressions were detected by qRT-PCR. Cell proliferation was assessed by CCK-8. Left atrial electroanatomical voltage maps were created using PentaRay catheters and a 3-dimensional mapping system. Key findingsOPN was highly expressed in the circulation of AF patients and was further increased with the progression of AF. In addition, correlation analysis showed that circulating OPN positively related with low-voltage areas (LVAs, a marker of atrial fibrosis) in AF patients. Immunohistological staining and immunoblotting revealed an increased expression of OPN in AF patients who present a higher degree of atrial fibrosis. Furthermore, in vitro studies in cultured human atrial fibroblasts (hAFs) demonstrated that OPN promoted the proliferation of fibroblasts and increased production of collagen I and fibronectin. Mechanistically, the profibrotic effects of OPN on atrial fibroblasts were determined via activating Akt/GSK-3β/β-catenin signaling and suppressing autophagy. SignificanceThis study uncovered a previously unrecognized profibrotic role of OPN in atrial fibrosis, which was achieved through activation of Akt/GSK-3β/β-catenin signaling pathway and suppression of autophagy, implying a promising therapeutic target in atrial fibrosis and AF.

Association of Left Atrial Appendage Voltage with Ischemic Stroke in Patients with Atrial Fibrillation.

Low atrial voltage is associated with an increased risk of stroke. The relationship between left atrial appendage voltage (LAAV) and ischemic stroke remains unknown. Low LAAV may predict the prevalence of ischemic stroke in patients with atrial fibrillation (AF). A total of 1108 patients with AF referred for catheter ablation were consecutively included from January 2015 to May 2018. The patients were divided into stroke and control groups based on previous ischemic stroke by neuroimaging criteria. LAAV was measured with a circular mapping catheter in sinus rhythm after ablation. Variables were compared, and logistic regression was performed to assess the relationship between LAAV and stroke. A total of 120 patients (10.8%) had a history of ischemic stroke. The patients in the stroke group were older and had higher percentages of hypertension, diabetes mellitus and coronary/vascular disease. The CHA2DS2-VASc score was higher and left atrial diameter was larger in the patients with stroke. More left atrial appendage thrombi and spontaneous echo contrast were detected in the stroke group. LAAV was significantly lower in the stroke group compared with the controls (5.3 ± 1.8 mV vs. 6.5 ± 1.8 mV; p < 0.001). Multivariate logistic regression revealed that a lower LAAV was associated with increased stroke prevalence [odds ratio = 0.75; 95% confidence interval (CI) 0.65-0.87; p < 0.001]. LAAV had a predictive value, with an area under the curve of 0.83 (95% CI 0.79-0.87; p < 0.001). With an optimal cut-off value of 5.2 mV for LAAV, the sensitivity and specificity were 75% and 74%, respectively. Lower LAAV in AF patients was associated with increased ischemic stroke prevalence. Whether LAAV is related to incident stroke requires further studies.

P605Correlation of left atrial phasic transport function and arrhythmogenic substrate in patients with atrial fibrillation: cardiac magnetic resonance feature tracking and bipolar voltage mapping

Abstract Background Bipolar voltage mapping is a widely accepted approach to identify areas of arrhythmogenic substrate in patients presenting for atrial fibrillation (AF) ablation. However, until now little is known about the correlation of left atrial (LA) bipolar voltage distribution and LA transport function. Purpose To study the impact of LA low voltage zones (LVZ) on LA transport function. Methods 107 consecutive patients presenting for ablation of symptomatic AF (34 paroxysmal AF, 73 persistent AF) were prospectively enrolled. Each patient underwent cardiac magnetic resonance imaging (CMR) within 24 hours prior to the ablation procedure. 59 patients were in sinus rhythm (SR) and 48 in AF. LA phasic indexed volumes (LAVi) and ejection fractions were calculated using biplane area length formula. In addition LA phasic strains and strain rates were analyzed using dedicated software (Figure 1A &amp; B). LA bipolar voltage mapping was performed prior to beginning of ablation in sinus rhythm using a 3-dimensional mapping system and LVZ were defined as areas of bipolar voltage &lt;0.5mV. Results LVZ were present in 47 patients (23 in SR). The area of LVZ was 14.6cm2 (5.3–34.0). For patients in AF at the time of CMR only elevated minimal and maximal LAVi (p=0.001 and p=0.002 respectively) but no LA functional parameter was predictive for the occurrence of LVZ. In contrast for patients in SR all LA phasic volumes (endsystolic, pre atrial contraction and enddiastolic LAVi) and LA function parameters (passive, active and total ejection fraction (EF), reservoir, conduit and booster pump strains and strain rates) were predictive for the occurrence of LVZ. After clustered and pooled multivariate logistic regression only impaired booster pump strain rate was still predictive for occurrence of LVZ (OR 0.974, 95% CI 0.950–0.998, p=0.036). In addition Pearson correlation analysis revealed a strong link between LA booster pump functional parameters and cm2 expansion of LVZ areas: LA active EF, LA booster pump strain and SR (r=−0.42, p=0.044; r=−0.47, p=0.024; r=−0.65, p=0.001 [Figure 1C] respectively). Conclusion For patients in SR LA transport function is closely linked to the occurrence of LA LVZ and outperforms LA volumetric measurements for the prediction of LA LVZ. Furthermore LA booster pump function parameters show robust correlation to the extension of LA LVZ.

Reverse electrical and structural remodeling of the left atrium occurs early after pulmonary vein isolation for persistent atrial fibrillation.

Adverse left atrial (LA) remodeling is known to be associated with persistent atrial fibrillation (PeAF). The time course and pattern of reversal of LA remodeling following catheter ablation is poorly understood. We aimed to evaluate LA chamber volumes and dimensions, LA conduction velocities, and LA bipolar voltages at baseline and at 2months after catheter ablation for PeAF. Twenty-three patients with PeAF underwent detailed LA mapping during fixed rate atrial pacing using the CARTO3 navigation system prior to undergoing pulmonary vein isolation. All patients returned for protocol-mandated repeat electrophysiology study at 2months, irrespective of symptoms or arrhythmia recurrence, during which all measurements were repeated using an identical mapping protocol. Patients then underwent daily ECG monitoring for 12months. Nineteen out of twenty-three (83.6%) patients had durable PVI of all veins at repeat electrophysiology study, while 4 (17.4%) patients had late reconnection of a single vein each. In the blinded offline analysis, LA volume at follow-up was significantly lower as compared with baseline (55 ± 14mL/m2 vs. 65 ± 15mL/m2, P < 0.001). LA conduction velocities were significantly greater at 2months (0.90 ± 0.13m/s vs. 0.78 ± 0.13m/s, P = 0.01). There was non-uniform regional LA voltage evolution, with a significant increase in bipolar voltages observed on the LA posterior wall (2.18 ± 0.85mV vs. 1.83 ± 0.49mV, P = 0.04), but not elsewhere. Individual variables of remodeling were not associated with AF recurrence. Significant structural and electrical reverse remodeling of the LA can be seen as early as 2months following successful catheter ablation for PeAF.

Quantitative assessment of left atrial scar using high-density voltage mapping and a novel automated voltage analysis tool.

Left atrial (LA) fibrosis plays an important role in the pathogenesis and perpetuation of atrial fibrillation (AF). It may be identified by bipolar voltage (BiV) mapping, but quantification of fibrosis which previously relied on visual estimation of scar has been shown to be inaccurate. Our aim was to use a novel automated voltage histogram analysis (VHA) tool to quantify LA scar burden accurately in patients with AF. LA voltage was assessed in 100 consecutive patients undergoing first pulmonary vein isolation (PVI) for paroxysmal or persistent AF using a circular multielectrode catheter to create high-density LA BiV maps which were analysed using the VHA tool after the procedure. High-density electro-anatomic maps took 10min to create and contained a median of 1049 points. The VHA algorithm accurately quantified the burden of Diseased LA Tissue (≤ 0.5mV) and Dense LA Scar (≤ 0.2mV) with a median of 17.8% and 3.5% respectively. A quartile classification was applied based on diseased LA tissue burden. Patients in class IV with the highest diseased LA burden were older (p < 0.0001), more likely female (p = 0.0095), had higher CHA2DS2-VASc scores (p = 0.0024) and were more likely to have persistent rather than paroxysmal AF (p = 0.0179) than those in classes I-III. The VHA algorithm is able to quantify percentage surface area voltage rapidly and according to preset ranges for the first time. The algorithm offers the potential for classification of patients undergoing AF ablation into different classes of diseased LA burden, which may have diagnostic, therapeutic and prognostic implications.

Cryoballoon ablation for persistent atrial fibrillation in patients without left atrial fibrosis.

The role of cryoballoon (CB) pulmonary vein isolation (PVI) for patients with persistent atrial fibrillation (AF) is controversial, since long-term success can be poor. We performed left atrial voltage mapping before CB PVI and determined AF-free survival depending on the extent of low-voltage areas (LVAs). We consecutively enrolled 60 patients with persistent AF (average age, 60.6 ± 12.9 years; CHA2 DS 2 VASc score, 2.3 ± 1.6; and left atrial size 46.0 ± 5.2 mm) who were planned for CB PVI. Before ablation, we performed left atrial voltage mapping (Abbott EnSite Precision or Velocity). LVAs were defined if local bipolar signal amplitudes were less than 0.5 mV during sinus rhythm. Thirty-seven patients did not show significant LVAs (<10%), while 12 patients had LVAs between 10% and 30% and 11 patients showed substantial LVAs greater than 30% of the left atrial area. CB PVI could be successfully performed in all patients. A 7-day holter monitoring was obtained 3, 6, and 12 months after ablation. After a 12-month follow-up time, 83.8% of patients without LVAs (<10%) were free of atrial fibrillation, while 50.0% of patients with 10% to 30% LVAs and 9.1% of patients with LVAs more than 30% had stable sinus rhythm. The degree of atrial fibrosis correlated with the risk of AF recurrence. In patients with persistent AF undergoing CB PVI, the extent of left atrial LVAs predicts an AF-free survival. CB PVI seems to be a highly effective treatment for patients with persistent AF without atrial fibrosis.

Combination of Circulating Type I Collagen-Related Biomarkers Is Associated With Atrial Fibrillation

BackgroundA combination of circulating biomarkers associated with excessive myocardial collagen type-I cross-linking or CCL+ (i.e., decreased carboxy-terminal telopeptide of collagen type-I to matrix metalloproteinase-1 ratio) and with excessive myocardial collagen type-I deposition or CD+ (i.e., increased carboxy-terminal propeptide of procollagen type-I) has been described in heart failure (HF) patients and associates with poor outcomes. ObjectivesThe purpose of this study was to investigate whether the CCL+CD+ combination of biomarkers associates with atrial fibrillation (AF). MethodsBiomarkers were analyzed in serum samples from 242 HF patients (study 1) and 150 patients referred for AF ablation (study 2). Patients were classified into 3 groups (CCL−CD−, CCL+CD− or CCL−CD+, and CCL+CD+) in accordance to biomarker threshold values. Left atrial electroanatomic high-density mapping was performed in 71 patients from study 2. ResultsIn study 1, 53.7% patients had AF at baseline and 19.6% developed AF (median follow-up 5.5 years). Adjusted odds and hazard ratios associated with baseline and new-onset AF, respectively, were both ≥3.3 (p ≤ 0.050) in CCL+CD+ patients compared with CCL−CD− patients, with nonsignificant changes in the other group. In study 2, 29.3% patients had AF recurrence during 1-year post-ablation. The adjusted hazard ratio for AF recurrence was 3.4 (p = 0.008) in CCL+CD+ patients compared with CCL−CD− patients, with nonsignificant changes in the other group. The CCL+CD+ combination added incremental predictive value over relevant covariables. CCL+CD+ patients exhibited lower left atrial voltage than the remaining patients (p = 0.005). ConclusionsA combination of circulating biomarkers reflecting excessive myocardial collagen type-I cross-linking and deposition is associated with higher AF prevalence, incidence, and recurrence after ablation.