Enlarged Left Atrium Research Articles

Cross-Sectional Relationship Between Atrial Conduction Delay and Arterial Stiffness in Patients with Obstructive Sleep Apnea.

Prolonged P-wave duration (PWD), which indicates atrial conduction delay, is a potent precursor of atrial fibrillation (AF) that may be induced by obstructive sleep apnea (OSA). The cardio-ankle vascular index (CAVI), which is an arterial stiffness parameter, is elevated in patients with OSA; moreover, an increased CAVI is associated with atrial conduction delay through left atrium enlargement in association with left ventricular diastolic dysfunction. We aimed to examine the relationship between the CAVI and PWD in patients with OSA. We included patients with a sinus rhythm who underwent overnight polysomnography. We measured the PWD and CAVI on standard 12-lead electrocardiograms; further, we analyzed the relationship between PWD and CAVI. We analyzed data from 300 participants (men, 89.0%; mean age, 52.3 ± 13.1 years; and body mass index, 26.2 ± 3.9 kg/m2). The mean PWD was 104.4 ± 10.4 ms while the mean CAVI was 7.5 ± 1.5. PWD was significantly correlated with CAVI (r = 0.478, p < 0.001); additionally, PWD and CAVI were directly associated with OSA severity (p = 0.002 and p = 0.002, respectively). Multivariate regression analysis revealed an independent significant correlation of PWD and CAVI with OSA severity. In patients with OSA, an increase in arterial stiffness is associated with atrial conduction delay.

Clinical Impact of Cryoballoon Ablation for Paroxysmal Atrial Fibrillation in Patients With Enlarged Left Atrium

The impact of cryoballoon ablation (CBA) for atrial fibrillation (AF) in patients with enlarged left atrium (E-LA) has not been sufficiently clarified. A total of 306 patients underwent an initial CBA for paroxysmal AF between February 2017 and March 2022 in our hospital. These patients were categorized into 2 groups according to the preprocedural left atrium (LA) diameter (LAD): E-LA group with LAD ≥40 mm and normal LA (N-LA) group with LAD <40 mm. We compared late recurrence (LR, defined as a recurrence of atrial tachyarrhythmia more than 3 months after the ablation) between the 2 groups. In addition, we made a further classification of the E-LA group into a severely E-LA (SE-LA) group with LAD ≥50 mm and mildly enlarged LA (ME-LA) group with LAD <50 mm and compared LR in the SE-LA, ME-LA, and N-LA groups. In the patients who experienced a second ablation procedure owing to LR, subsequent recurrences were also evaluated. After initial CBA, there was no significant difference in recurrence-free survival between E-LA and N-LA groups (p=0.447). In contrast, the SE-LA group showed the lowest incidence of recurrence-free survival in the SE-LA, ME-LA, and N-LA groups (p=0.012). However, when we analyzed recurrences after the ablation including second ablation procedure, there were no significant differences in recurrence-free survival among these 3 groups (p=0.103). In conclusion, patients with paroxysmal AF with enlarged LA showed favorable outcomes compared with those with N-LA after CBA.

Left Atrium Volume Reduction Procedure Concomitant With Cox-Maze Ablation in Patients Undergoing Mitral Valve Surgery: A Meta-Analysis of Clinical and Rhythm Outcomes

The management of an enlarged left atrium (LA) in mitral valve (MV) disease with atrial fibrillation (AF) is still being debated. It has been postulated that a reduction in LA size may improve patient outcomes. This meta-analysis aimed to assess rhythm and clinical outcomes of combined surgical AF treatment with or without LA volume reduction (LAVR) in patients undergoing MV surgery. A systematic review was performed and all available literature to May 2022 was included. The primary endpoint was analysis of early and late mortality and rhythm outcomes. Secondary outcomes included early and late cerebrovascular accident (CVA) and permanent pacemaker implantation. The search strategy yielded 2,808 potentially relevant articles, and 19 papers were eventually included. The pooled estimated rate of 30-day mortality was 3.76% (95% CI 2.52-5.56). The incidence rate of late mortality and late cardiac-related mortality was 1.75%/year (95% CI 0.63-4.84) and 1.04%/year (95% CI 0.31-3.53), respectively. At subgroup analysis when comparing the surgical procedure with and without AF ablation, the ablation subgroup showed a significantly lower rate of postoperative CVA (p<0.0001) and higher restoration to sinus rhythm at discharge (p=0.0124), with only a trend of lower AF recurrence at 1 year (p=0.0608). At univariable meta-regression, reintervention was significantly associated with higher late mortality (p=0.0033). In enlarged LA undergoing MV surgery, LAVR combined with AF ablation showed a trend of improved rhythm outcomes when compared with AF ablation without LAVR. Each LAVR technique has its advantages and disadvantages, which must be managed accordingly.

Prognostic Implications of the Extent of Cardiac Damage in Patients With Fabry Disease

BackgroundThere is limited evidence on the risk stratification of cardiovascular outcomes in patients with Fabry disease (FD). ObjectivesThis study sought to classify FD patients into disease stages, based on the extent of the cardiac damage evaluated by echocardiography, and to assess their prognostic impact in a multicenter cohort. MethodsPatients with FD from 5 Italian referral centers were categorized into 4 stages: stage 0, no cardiac involvement; stage 1, left ventricular (LV) hypertrophy (LV maximal wall thickness >12 mm); stage 2, left atrium (LA) enlargement (LA volume index >34 mL/m2); stage 3, ventricular impairment (LV ejection fraction <50% or E/eʹ ≥15 or TAPSE <17 mm). The study endpoint was the composite of all-cause death, hospitalization for heart failure, new-onset atrial fibrillation, major bradyarrhythmias or tachyarrhythmias, and ischemic stroke. ResultsA total of 314 patients were included. Among them, 174 (56%) were classified as stage 0, 41 (13%) as stage 1, 57 (18%) as stage 2 and 42 (13%) as stage 3. A progressive increase in the composite event rate at 8 years was observed with worsening stages of cardiac damage (log-rank P < 0.001). On multivariable Cox regression analysis, the staging was independently associated with the risk of cardiovascular events (HR: 2.086 per 1-stage increase; 95% CI: 1.487-2.927; P < 0.001). Notably, cardiac staging demonstrated a stronger and additive prognostic value, as compared with the degree of LV hypertrophy. ConclusionsIn FD patients, a novel staging classification of cardiac damage, evaluated by echocardiography, is strongly associated with cardiovascular outcomes and may be helpful to refine risk stratification.

Blood flow analysis with computational fluid dynamics in the left atrium after left atrial plication: a prospective study.

This study aimed to evaluate blood flow stagnation in an enlarged left atrium (LA) and prove that left atrial plication (LAP) could alleviate the stagnation. Five patients with chronic atrial fibrillation who underwent mitral valve surgery followed by LAP for an enlarged LA with a ≥ 60-mm diameter were included. We performed computational fluid dynamics (CFD) analysis using preoperative and postoperative computed tomography and four-dimensional flow magnetic resonance imaging. Additionally, computer graphics were used to create virtual left atrial appendage resection (LAAR) images. We performed CFD analysis to assess blood flow stagnation in the LA for three groups: preoperative, LAAR, and LAP. When the average and constant stagnation volumes were both set to 100 preoperatively, the average stagnation volumes of the LAAR and LAP groups were 67.42 ± 18.64 and 35.88 ± 8.20, respectively. The constant stagnation volumes of these groups reduced to 45.01 ± 7.43 and 21.14 ± 7.70, respectively. The LAP group also had significantly lower average and constant stagnation volumes than those in the LAAR group (p = 0.006 and p = 0.033, respectively). Blood flow stagnation was noted in the LAA and enlarged LA. CFD analysis revealed that LAP for the enlarged LA improved blood flow stagnation more than the virtual LAAR alone. UMIN000049923.

Prognostic implications of machine learning-derived echocardiographic phenotypes in community hypertensive patients

ABSTRACT Background Echocardiogram is commonly used to evaluate cardiac remodeling in hypertension (HTN). However, study on echocardiographic phenotypes and their prognostic implications in HTN is limited. Objective We aimed to evaluate the prognostic implications echocardiographic phenotypes in community hypertensive patients. Method A total of 1881 community hypertensive patients without overt cardiovascular disease and severe renal disease (mean age 62.8 years, women 57.9%) were included. Using Two-Step cluster analysis with four conventional echocardiographic variables, two clusters with distinct echocardiographic phenotypes were identified. Result The Cluster 1 (namely “mild-remodeling” HTN; n = 1492) had low prevalence of enlarged left atrium (LA; 0.9%) and left ventricular hypertrophy (LVH; 16.2%) and better LV diastolic function. They were younger and more likely to be men and had lower comorbid burden. The Cluster 2 (namely “severe-remodeling” HTN; n = 389) had higher prevalence of enlarged LA (26.0%) and LVH (83.0%) and worse LV diastolic function. They were older and more likely to be women and had higher comorbid burden. After a median follow-up of 4.2 years, compared to the Cluster 1, the Cluster 2 had higher incidence of cardiovascular (4.1% vs 1.7%; P = .006) and all-cause (9.8% vs 4.8%; P < .001) death, with adjusted hazard ratio of 2.80 (95% CI 1.39–5.62; P = .004) and 2.04 (95% CI 1.32–3.14; P < .001) respectively. Conclusion These findings indicate that the conventional echocardiographic variables-based algorithm could help identify asymptomatic community hypertensive patients at risk for cardiovascular and all-cause death. Further studies are needed to develop and validate phenotype-specific prevention and intervention strategies in HTN.

Radiographic findings of cardiopulmonary structures can predict hypertrophic cardiomyopathy and congestive heart failure in cats.

This study aimed to find the radiographic characteristics for the detection of hypertrophic cardiomyopathy (HCM) and congestive heart failure (CHF) in cats. Healthy cats (n = 35) and HCM cats with (21) and without (22) CHF. On radiography, the cardiac size using vertebral heart score, left atrium enlargement (LAE), and dilation of the pulmonary vessels were assessed. The sensitivity and specificity of the radiographic characteristics regarding LAE were evaluated with the echocardiographic left atrium to aortic root ratio as a reference. In HCM cats, cardiomegaly, LAE, and dilation of the caudal pulmonary artery were found compared with those in healthy cats. The LAE could be predicted using the elevation of the carina with 94.12% specificity but 17.5% sensitivity. When CHF developed, LAE and dilation of the caudal pulmonary vein (PV) were significantly different compared with those in HCM cats without CHF. The distal side of the summated shadow made by the right caudal PV with the ninth rib in HCM cats with CHF was significantly larger than that in HCM cats without CHF and a cut-off value of 5.35 mm was drawn with 75% sensitivity and 100% specificity. Although there was an overlapping of radiographic findings between healthy and HCM cats, radiographic assessment of LAE can be useful for predicting HCM and the distal side of the summated shadow made by the right caudal PV with the ninth rib can predict CHF in HCM cats.

Echocardiography identifies geometric and functional cardiac alterations in patients with Familial Partial Lipodystrophy

Abstract Funding Acknowledgements Type of funding sources: None. Lipodystrophy (LPD) is a rare condition characterized by levels of loss of adipose tissue in a generalized or partial form. Cardiovascular disease is a significant cause of morbidity in this population,n but cardiomyopathy associated with LPD is still not well described. We sought to characterize cardiac morphology and left ventricle function in patients with partial LPD with no cardiac symptoms. Methods This is a cross-sectional case-control study. Adult patients with clinical diagnosis of familial partial LPD and Controls were invited to collect echocardiographic images prospectively. Transthoracic echocardiography was performed with conventional bidimensional and Doppler techniques and LV Speckle-tracking technique. Left atrium (LA) dimension and volumes, LV dimension, thickness, mass, and diastolic and systolic function were measured. Data between groups compared with appropriate tests according to variable distribution. Relation between echocardiographic variables and LPD diagnosis were tested with simple and multiple regression models, considering the effect of systolic arterial blood pressure (SBP) as an independent variable. The significance level was set as p &amp;lt;0.05. Results twenty-nine patients with LPD were compared to 17 control. LPD patients and control group did not differ in age (44.58±11.77 vs. 43.84±13.32, p = 0.94), gender, BMI (26.73±4.30 vs. 24.52±5.04 Kg/ml, p = 0.05) or BSA (1.70±0.23 vs. 1.67±0.16, p = 0.9). Patients with LPD had statistically higher SBP (122.7±14.85 vs. 110.9±11.08, p = 0.02). LPD had LA higher dimension (37.27±4.44 vs. 32.12±4.25 mm, p = 0.001) and volume (LAVi)(30.17±7.24 vs. 24.94±9.04 ml/m2, p = 0.02), LV mass_i (79.29±17.38 vs. 67.10±19.36, p = 0.02), and also reduced diastolic LV parameters as mitral tissue Doppler E' lateral (11.07±3.48 vs. 14.94±2.35 cm/s, p = 0.001) and E' septal ( 8.0±2.73 vs. 11.38±2.02 cm/s, p = 0.001, and also E/E' ratio (7.89±2.22 vs. 6.35±1.29, p = 0.02). Parameters of LV systolic function as LVEF (64.70±4.56 vs. 62.15±4.35 %, p = 0.08) or GLS were not statistically different between groups (−17.06±2.70vs. −18.02±1.98%, p = 0.25). There was a positive relation of LA dimension ( β 5.6, p&amp;lt;0.001), wall thickness (β 1.3, p 0.011), tissue Doppler E' lateral (β −3.5, p = 0.002) and E' septal (β −3.2, p&amp;lt;0.001) to LPD diagnosis, even after adjusted for SBP. Conclusion patients with familial partial LPD present early cardiomyopathy with LV hypertrophy, LA enlargement, and LV diastolic dysfunction before LV systolic dysfunction. Echocardiographic parameters are related to LPD diagnosis independent of SBP.

The relation between left atrial and left ventricular size in a healthy population

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): The project was funded by grants from The Liaison Committee for Education, Research and Innovation in Central Norway, St. Olavs University Hospital (Trondheim, Norway), Nord-Trøndelag Hospital Trust (Levanger, Norway), and Simon Fougner Hartmann's Family Fund (Copenhagen, Denmark). Background The left atrium (LA) and ventricle (LV) are closely linked and adapt to meet metabolic demands. Reduced LV end-diastolic volume (LVEDV) and increased LA end-systolic volume (LAESV) is common in patients with diastolic dysfunction and with higher age. The remodeling of LA and LV in response to endurance exercise is thought to be balanced, and thus, the LA:LV ratio could help discriminate pathologic from physiologic LA enlargement. Purpose We aimed to describe the relative LA and LV chamber remodeling associated with the clinical characteristics age, sex, maximal oxygen consumption (VO2peak), HbA1C, body mass index, systolic blood pressure, and diastolic dysfunction. Methods Healthy participants included in a large longitudinal population study underwent clinical evaluation and cardiopulmonary exercise testing (CPET) in 2006–2008, followed by comprehensive echocardiography and CPET in 2017–18. Exclusion criteria were: 1) submaximal performance during CPET, 2) atrial fibrillation, or 3) presence of heart failure or a history of myocardial infarction. All examinations were performed by highly experienced personnel. All echocardiographic exams and analyses were performed by personnel affiliated a European Association of Cardiovascular Imaging accredited echo-laboratory. Results In total, 1,349 participants were included. Mean (SD) age was 58 (12) years, and 52% were women. The LA:LV ratio was higher with higher age due to lower LVEDV and stable LAESV (Figure 1). Age alone explained 12% (p&amp;lt;0.001) of variance for the LA:LV ratio and men had higher LA:LV ratios than women (0.55 vs. 0.50, p &amp;lt;0.001). All examined clinical characteristics showed significant associations with LA:LV ratios in univariate regression analyses. In adjusted analyses, increased VO2peak was significantly associated with increased LA:LV ratio, but with a small effect-size without clinical significance. In the subsample with indexed LAESV &amp;gt;34mL/m2, increased VO2peak was significantly associated with increased LA:LV-ratio in adjusted analyses (p &amp;lt;0.001). Ten-year change in VO2peak was not significantly associated with LA:LV ratio in adjusted models for the total population, nor in the subgroup with indexed LAESV &amp;gt;34 mL (p = 0.181). Multiple logistic regression showed that higher LA:LV ratio was associated with increased risk of diastolic dysfunction with an OR (95% CI) of 2.4 (1.5, 4.0) per SD increase in LA:LV-ratio, adjusted for age, sex, systolic blood pressure, HbA1c, and BMI (p &amp;lt; 0.001). LA strain measures, E/e’ ratio, and TR velocity were significantly associated with the LA:LV ratio, while other diastolic function parameters were not. Conclusion The LA:LV ratio increases with higher age due to reduced LVEDV and stable LAESV. VO2peak was not a robust predictor of LA:LV ratio in this population. Future studies should evaluate the relative remodeling of LA and LV with repeated measurements of echocardiographic indices and CPET to better define the role of this ratio.

Left atrial strain predicts improvement in left atrial functions of severe rheumatic mitral stenoses undergoing successful percutaneous transmitral commissurotomy.

Chronic rheumatic heart disease (RHD) is prevalent in India. The mitral valve in isolation or combination with the aortic or tricuspid valve is involved in 31.6% and 52.8% of chronic RHD patients, respectively. The left atrium (LA) functions as a reservoir during the cardiac cycle. Therefore, the LA enlargement leads to longitudinal lengthening, measured as a positive strain, permitting the measurement of the longitudinal strain of LA. This study aimed to assess the LA functions using peak atrial longitudinal strain (PALS) in patients with severe rheumatic mitral stenoses (MS) in sinus rhythm who underwent successful percutaneous transvenous mitral commissurotomy (PTMC). We recruited 56 patients with severe rheumatic MS for the study, of which 06 PTMC procedures were considered unsuccessful. So, 50 patients of chronic severe rheumatic MS in sinus rhythm undergoing PTMC were enrolled in a tertiary care centre of the Armed Forces from August 2017 to May 2019. Patients included in the study were not consecutive, and patients with atrial fibrillation (AF) were excluded. PALS improved post-PTMC (P<.001) in this study, effectively concluding that PALS is impaired in patients with severe symptomatic MS and is acutely enhanced after treatment. PALS is a good indicator of LA function and may predict the success of PTMC on the rheumatic mitral valve.

Chronotropic incompetence and exercise capacity after cardiac surgery with left atrium incision

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Chronotropic incompetence (CI) is sometimes observed during exercise training of cardiac rehabilitation in patients who underwent cardiac surgery, however, little is known which factors affect to the incidence of CI and exercise capacity of those patients. Purpose Because the possibility exists that cardiac sympathetic nerves might be impaired by surgical procedure, moreover CI is sometimes observed in patients after mitral valve surgery, we hypothesized that the incidence of CI was higher in patients with left atrium incision (LAI) during surgical operation as compared with those without LAI. And if so, which factor determines the exercise capacity of patients after cardiac surgery with LAI. We thus aimed this study to elucidate the hypothesis with cardiopulmonary exercise testing (CPX). Methods We performed CPX in total 153 patients who had undergone elective cardiac operation (45 patients with LAI, age 60.5±11.0; 108 patients without LAI, age 62.0±11.7). We analyzed chronotropic response index (CRI), peak oxygen uptake (peak VO2/W), anaerobic threshold (AT), and peak oxygen pulse (peak VO2/HR) with CPX, echocardiography, and blood hemoglobin concentration (Hb). Results The value of CRI was significantly reduced in the patients with LAI as compared with those without LAI (with LAI 0.24±0.22 vs. without LAI; 0.44±0.18, p&amp;lt;0.001). Exercise capacity such as peak oxygen uptake (peak VO2), anaerobic threshold showed no significant difference between two groups. In patients with LAI, peak VO2 showed significant correlations between peak oxygen pulse (peak VO2/HR; r=0.36, p&amp;lt;0.05), Hb (r=0.40, p&amp;lt;0.01) and left atrium dimension (LAD) measured by echocardiography (r=-0.54, p&amp;lt;0.001). Conclusions The present study demonstrated that higher incidence of CI was shown in patients with LAI as compared with those without LAI. Moreover peak VO2 of patients with LAI showed significant correlations with peak VO2/HR, Hb and LAD. These results suggest that 1) left atrium incision impairs cardiac sympathetic nerves and causes CI, 2) peak VO2/HR and Hb which is essential element of oxygen pulse are important factors for exercise capacity in patients after LAI with CI. Left atrium enlargement may indicates pre-operative damages of left atrium, 3) LAD which may indicate left atrium function, also is an important factor of exercise capacity in those patients.

The critical isthmus of left atrial anterior wall flutter is mostly circumscribed into a small area immediately behind the aortic root. Implications for catheter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial flutters (LAFL) are typically observed in patients with previous ablation lines or surgery in the left atrium (LA). Less frequently, scar-related left atrial anterior wall (LAAW) flutters may occur. Although the presence of low-voltage areas (LVAs, a surrogate of scar) in the LA is considered an arrhythmogenic substrate and a marker of atrial cardiomyopathy, the pathophysiologic factors responsible for its formation remain unclear. We hypothesized that compression of the LAAW by the aortic root could be responsible of LVAs found in the LAAW, and therefore, be the substrate for the development of LAAW flutter. Purpose We aimed to describe: 1) the relationship between the aortic root and the presence of LVAs in the LAAW, which is the substrate for reentry; and 2) the clinical and electrophysiological characteristics of LAAW atrial flutter. Methods Consecutive patients referred for LAFL ablation between April 2019 and September 2022 in a single center were retrospectively collected. Among 55 patients with LAFL, 10 (18%) demonstrated a macroreentrant circuit with a critical isthmus identified in the LAAW, in the absence of previous ablation lines or surgery, and were included in the analysis. Previous pulmonary vein isolation (PVI) was not an exclusion criterion. All patients underwent a multidetector computerized tomography (MDCT) prior to the procedure and the images were analyzed using ADAS 3DTM imaging platform. Activation mapping was performed in all patients using a multielectrode mapping catheter and CARTO 3 navigation system. Results 9 of 10 patients were male (mean age 74,3 ± 6,3 years). LA enlargement was present in all patients (48,3 ± 4,7 mm) and the mean aortic root diameter was 34,8 ± 3,4 mm. The mean LAAW flutter cycle length was 293,4 ± 68,3 ms. In 9 of the patients (90%), the LAAW flutter critical isthmus was just behind the aortic root, separated by &amp;lt; 1 mm according to the LA-aortic root fingerprinted isodistance map (mean fingerprinted isodistance area was 5,8 ± 2,5 cm2). The remaining patient had the critical isthmus just below the aortic root, between the area in contact with the latter and the mitral annulus. Furthermore, in all cases, the critical isthmus was immersed in LVAs. All but 1 LAAW flutter terminated during radiofrequency (RF) energy applications and rendered it non-inducible. After a median follow-up of 13,6 months (IQ range 5,3-21,6), 7 patients (70%) remained without recurrences. Conclusion In patients with LAAW atrial flutter, the presence of LVAs and the critical isthmus of the tachycardia are mostly circumscribed into small areas immediately behind the aortic root. Knowledge of this close relationship and the use of the isodistance map could be useful when mapping and ablating LAAW flutter, helping to straightforward the ablation procedure.

The novel left atrial anterior 'seatbelt' line reduces sustained atrial arrhythmia by 72% compared to pulmonary vein isolation alone in a cohort of 400 virtual atria models

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No.860974. Background The success-rate of pulmonary vein isolation (PVI) is modest in persistent atrial fibrillation (AF), but additional empirical ablation, such as posterior wall isolation (PWI), has not been shown to reduce the rate of AF recurrence. The "seatbelt", an anterior linear ablation lesion connecting the right superior pulmonary vein to the mitral annulus, is a novel substrate modification approach that is yet to be tested in a large-scale randomised clinical trial. Purpose To use in-silico trials with human-based modelling and simulation to compare the efficacy of (i) PVI alone, (ii) PVI and PWI (PVI+PWI), or (iii) PVI and seatbelt (PVI+SB) for the prevention of atrial arrhythmia in large populations of virtual patient models. Methods AF was simulated in a cohort of 400 virtual atrial models with anatomical and electrophysiological variability, with AF persisting for &amp;gt;7 seconds defined as sustained. Models which sustained AF were each independently subjected to all three ablation approaches before repeating the AF induction protocol. Results Three hundred forty-four (86%) atrial models developed sustained AF at baseline. After applying the ablation lesions, substantially fewer models sustained atrial arrhythmias in the PVI+SB group (50 [14%] vs. 134 [39%] with PVI+PWI vs. 172 [50%] with PVI). PVI+SB was more effective than PVI and PVI+PWI in preventing both AF and atrial flutter (i.e., presence of a single rotor), since PVI and PVI+PWI led to the formation of anatomical re-entries around the rings of the pulmonary veins and the posterior wall of the left atrium, respectively (Figure). Therefore, PVI+SB restricted atrial flutter mainly to the right atrium (either anatomical, around the inferior cava vein, or functional, meandering throughout the venous portion of the right atrium, Figure). Importantly, in all three ablation strategies, the likelihood of AF recurrence was directly proportional to the surface area of the right atrium (AF probability increased 0.95%/cm², 0.88%/cm² and 0.56%/cm² after PVI+SB, PVI+PWI and PVI, respectively). The role of the right atrial size was less accentuated for PVI alone, since after the ablation the entire left atrial body was still available for rotor anchoring. Moreover, an enlarged left atrium enabled the appearance of micro-re-entries in the anterior and inferior wall of the left atrium, even after applying floor and roof lines. One atrial model additionally presented a rotor in the posterior wall of the left atrium after completely isolating it from the left atrial body. Conclusion(s) In a cohort of 400 virtual atrial models, PVI+SB reduced sustained atrial arrhythmias by 72% compared to PVI alone and by 64% to PVI+PWI, but AF could still originate in an enlarged right atrium.

Cardio-vocal syndrome - How 'benign' condition can turn 'malignant'?

Cardio-vocal syndrome (also called as Ortner's syndrome) is hoarseness of voice due to compression of left recurrent laryngeal nerve secondary to enlarged cardiac chambers and structures. We present two cases of Ortner's syndrome secondary to atrial fibrillation causing enlargement of left atrium compressing the left recurrent laryngeal nerve, and their clinical outcomes.

The spatiotemporal electrogram dispersion ablation targeting rotors is more effective for elderly patients than non-elderly population.

Modulating atrial fibrillation (AF) drivers has been proposed as one of the effective ablation strategies for non-paroxysmal AF (non-PAF). However, the optimal non-PAF ablation strategy is still under debate because the exact mechanisms of AF persistence including focal activity and/or rotational activity, are not well-understood. Recently, spatiotemporal electrogram dispersion (STED) assumed to indicate rotors in the form of rotational activity is proposed as an effective target for non-PAF ablation. We aimed to clarify the effectiveness of STED ablation for modulating AF drivers. STED ablation plus pulmonary vein isolation was applied in 161 consecutive non-PAF patients not undergoing previous ablation. STED areas within the entire left and right atria were identified and ablated during AF. After the procedures, the STED ablation's acute and long-term outcomes were investigated. (1) Despite a more effective acute outcome of the STED ablation for both AF termination and non-inducibility of atrial tachyarrhythmias (ATAs), Kaplan-Meier curves showed that the 24-month freedom ratio from ATAs was 49%, which resulted from the higher recurrence ratio of atrial tachycardia (AT) rather than AF. (2) A multivariate analysis showed that the determinant of ATA recurrences was only a non-elderly age, not long-standing persistent AF, and an enlarged left atrium, which were conventionally considered as key factors. STED ablation targeting rotors was effective in elderly non-PAF patients. Therefore, the main mechanism of AF persistency and the component of the fibrillatory conduction might vary between elders and non-elders. However, we should be careful about post-ablation ATs following substrate modification.

PO-03-092 MACHINE LEARNING ANALYSIS OF THE PREDICTORS OF AF RECURRENCE POST-ABLATION IN PATIENTS UNDERGOING PRE-ABLATION MRI

Catheter ablation, a widely performed rhythm control strategy for atrial fibrillation (AF), has variable results in the complete suppression of arrhythmia recurrence, especially in obese patients. Structural remodeling of the left atrium (LA), evidenced by LA enlargement and fibrosis, is a well-known substrate for AF. Epicardial adipose tissue (EAT) is thought to be a crucial factor mediating cardiovascular disease in obesity, it can result in electrical heterogeneity and local conduction block forming a substrate for AF. We aimed to apply a machine learning approach to assess the predictors of AF recurrence following catheter ablation in AF patients undergoing pre-ablation cardiac magnetic resonance (CMR). 101 AF patients underwent CMR prior to catheter ablation. Fibrotic remodeling was assessed using the late gadolinium enhancement sequence. EAT was assessed using the novel fat-water separation 3D Dixon sequence. Panel A shows posterior and anterior views of a representative LA model showing fibrotic remodeling and EAT. Patients were followed for AF recurrence using ambulatory monitoring and 12-lead ECGs. A random forest classifier with 5x stratified cross-validation was trained to predict AF recurrence post-ablation and SHapley Additive exPlanations (SHAP) analysis was used to assess feature importance in the prediction of AF recurrence. During an average follow-up period of 1 year, post-ablation AF recurrence occurred in 31 (30.7%) patients. Patients with AF recurrence post-ablation had higher LA EAT index (20.7 [16.9, 30.4] vs 13.7 [10.5, 20.1] mL/m2, p<0.001), and higher LA volume index (66 [52.6, 77.5] vs 49.9 [37.7, 61.8] mL/m2, p=0.001). There was a trend toward a higher fibrosis burden in patients who had an AF recurrence (18.6% vs 16.1%, p=0.076). The classifier predicted AF recurrence post-ablation with an AUC of 0.67 ± 0.09 (Panel B). SHAP analysis revealed that for the overall population, the three most important features in the prediction of AF recurrence post-ablation were LA volume index, LA EAT index, and LA fibrosis (Panel C). LA enlargement, fibrosis and EAT, markers with clear ties to AF pathophysiology, are predictors of AF recurrence after ablation. Future studies testing the value of an imaging-based ablation failure prediction calculator, as well as studies to elucidate the mechanism of ablation failure, are required.

PO-01-108 ELUCIDATING THE MECHANISM OF ATRIAL FIBRILLATION IN LAMIN A/C HEART DISEASE USING HUMAN IPSC-DERIVED ATRIAL CARDIOMYOCYTES

Mutations in the LMNA gene, encoding the nuclear envelope proteins lamin A/C, cause cardiac arrhythmias, conduction disease, and dilated cardiomyopathy. Malignant arrhythmias such as atrial fibrillation (AF) and ventricular tachycardia are common and pose an increased risk of stroke and sudden cardiac death. To investigate the etiological mechanisms by which a heterozygous pathogenic LMNA-S143P mutation causes early-onset AF using mature human iPSC-derived atrial cardiomyocytes (hiPSC-aCM) generated from a large kindred with a strong cardiac phenotype. Detailed phenotyping of a 4-generation family pedigree and generation of hiPSCs from the proband using a comprehensive approach for the differentiation of mature hiPSC-aCMs. Action potential duration was measured by optical voltage mapping. Calcium transients were measured by confocal microscopy. The proband (III-3) is a 42-year-old female of European and Asian descent who developed symptomatic early-onset AF at age 35. She underwent direct current cardioversion (DCCV), pulmonary vein isolation, and implantation of a biventricular pacemaker. Cardiac MRI showed an enlarged left atrium with preserved left ventricular systolic function (EF 56%). A detailed family history revealed early-onset AF and AV block, congestive heart failure (CHF), and sudden death (Fig. 1). Genetic testing of the proband revealed a pathogenic missense mutation in LMNA (c427T>Cp. Ser143Pro). Mature LMNA-S143P-hiPSC-aCMs displayed prolongation of the atrial action potential duration (APD90) with delayed afterdepolarizations, abnormal calcium transients, and AF as compared to wild-type hiPSC-aCMs. Detailed phenotyping of a large LMNA kindred revealed a phenotype of AF, cardiac conduction disease, dilated cardiomyopathy, and sudden death. Our hiPSC-aCM studies uncovered a triggered mechanism for the AF with ion channel remodeling and pave the way for targeting calcium handling proteins as a potential therapeutic strategy in LMNA associated arrhythmias.

55. The Duration of Hypertension does not Affect Left Atrial Volume Index and Left Ventricular Mass Index in Hypertensive patients at Regional Referral Hospital

Background: Increased left atrial size and volume and left ventricular hypertrophy can be used as prognostic indicators of cardiovascular morbidity and mortality. Enlargement of left atrium and hypertrophied of LV are already known associated with several factors, but many of them studied in mild-hypertension case in primary/secondary health care. The objective of this study was to evaluate the effect of hypertension duration on Left Atrial Volume Index (LAVi) and Left Ventricular Mass Index (LVMi) in hypertensive patient at Regional Referral Hospital. Methods: Data from hypertension registry at Dr Hasan Sadikin General Hospital, Bandung, from March to December 2022 were collected. Patients with reduced left ventricular systolic function, moderate to severe valvular heart disease, professional athlete, pregnancy, congenital heart disease, pulmonary arterial hypertension were excluded. Patients’ hypertension duration, gender, age, echocardiographic measurement was collected. Linear regression analysis was conducted to evaluate effects of hypertension duration on LAVi and LVMi from echocardiographic evaluation. Results: A total of 94 patient's was studied with median age: 60.5 (22–75) years old and male: 50%. The median duration of hypertension was 5 (0.08–44) years. The median value of LAVi was 20.9 (10.1–56.4) ml/m2, The median LVMi was 124.65 (52.9–281.8) g/m2. There was no significant association between duration of hypertension and LAVi, R2 = .009, P = .482, F = .370, CI (19.389, 24.456). There was no significant association between duration of hypertension and LVMi: R2 = .006, P = .446, F .58, CI (120.06, 138.72) Conclusion: Hypertension duration doesn’t significantly affect Left Atrial Volume Index and Left Ventricular Mass Index in Hypertensive patients at Regional Referral Hospital.

Evaluation of Left Atrial Size in Patients with Hypertension with Left Ventricular Hypertrophy in a Tertiary Care Hospital of Nepal

Background: The hypertensive heart disease is characterized by left ventricular hypertrophy (LVH), atrial remodeling and AF. The impact of hypertension on the left atrium is little known. LVH is a link between hypertension and left atrium enlargement (LAE). LAE raises the suspicion of increased BMI, DM, dyslipidemia in hypertension. Thus, the aim of this study is to evaluate the LA size hypertensive patients without metabolic disorder and to evaluate whether there is a relationship between LVH and LAE. Methods: This is a prospective, observational study conducted in SGNHC, Kathmandu, Nepal. Our Study included 91 hypertensive patients fulfilling inclusion criteria from August 2021 to January 2022. Results: 91 patients were enrolled for the study, out of which 50 (54.9%) were males and 41 (45.1%) were females. Mean age of patients was 47.77±12.1 years. 23(25%), 28(31%) and 40 (44%) patients fulfilled SV3+RaVL, SV1+RV5, RaVL criteria respectively of LVH. 10(11%),12 (13%) and 25(27.5%) satisfied the criteria of LVMI, IVSD, RWT respectively. The mean values of LA diameters, area, volume and volume Index were calculated. There were a significant associations between left ventricular internal diameters and age with LAVI (p-value &lt;0.05). There was a mild positive association between SBP more than 140mm of Hg and LAVI, although not significant statistically. Similarly, there was a significant association between increased BMI above 25 and LAVI more than 34. Conclusion: LAE is associated with LV diameter, age, BMI and SBP. J Inv Clin Cardiol 2023; 5(1): 19-23

Abnormal left atrial strain is associated with eventual diagnosis of atrial fibrillation in patients with embolic stroke of undetermined source

Abstract Funding Acknowledgements Type of funding sources: None. Background Patients with embolic stroke of undetermined source (ESUS) have no immediate attributable cause despite initial evaluation. Occult paroxysmal atrial fibrillation (pAF) diagnosed on prolonged electrocardiographic monitoring may be subsequently found in 20% of patients initially classified as ESUS [1]. Anatomic and functional alterations of left atrium (LA) are known to predict pAF in the general population [2]. Recent studies have suggested that LA dysfunction is linked to the risk of development of pAF in stroke patients and may precede LA enlargement [1]. LA strain analysis may be helpful to predict the development of pAF as it can detect subclinical functional impairment [2]. The aim of this study was to analyse whether LA strain can be a marker for the development of new-onset AF in patients with ESUS and sinus rhythm. Methods Our single-centre observational cohort study examined 157 patients hospitalised for ESUS in our tertiary hospital between October 2014 and October 2017 who underwent AF monitoring with an implantable loop recorder (ILR). These patients were followed up for occurrence of new-onset pAF and recurrence of ischaemic stroke. All patients underwent transthoracic echocardiography (TTE) during index hospitalisation as part of the workup for ESUS. Echocardiographic images were obtained and analysed post-hoc for two-dimensional (2D) speckle tracing deformation parameters. These LA strain parameters were analysed against the primary outcome of AF detection and secondary outcome of recurrent ischaemic stroke. Results A total of 157 ESUS patients, with a mean age of 61.0 (±11.6) years, were followed up for a median duration of 3.5 (interquartile range 3.29) years. ILR monitoring detected AF in 27 patients (17.2%). 27 patients developed recurrent ischaemic strokes. Of the 27 patients with newly diagnosed AF on ILR, 24 (88.9%) were commenced on oral anticoagulation; the remaining 3 patients were not on anticoagulation due to high bleeding risk and frailty. Patients who had newly diagnosed AF had more impaired left atrial reservoir strain (LASr; 23.5% ± 10.3%, P = 0.042) and left atrial conduit strain (LAScd; -10.5% ± 5.3%, P = 0.003) compared with patients who remained in sinus rhythm. Multivariable logistic regression analysis adjusting for age, sex, hypertension, hyperlipidaemia, diabetes mellitus and left ventricular ejection fraction (LVEF) showed that LAScd was associated with occult AF (adjusted odds ratio [aOR] = 1.110, 95% CI, 1.019-1.209, P = 0.017) and the composite outcome of AF and recurrent ischaemic stroke (OR = 1.069, 95% CI, 1.014-1.138, P = 0.038). Abnormal LAScd was significantly associated with occult AF even when stratified by normal LA volume index (LAVI) (OR = 2.672, 95% CI, 1.035-8.548, P = 0.048) and high LAVI (OR = 1.713, 95% CI, 1.023-2.869, P = 0.041). Conclusion Impaired left atrial strain was associated with occult AF detection in patients with ESUS undergoing ILR monitoring.