Atrial Fibrillation In Hypertrophic Cardiomyopathy Research Articles

Prediction of incident atrial fibrillation in hypertrophic cardiomyopathy

Background and aimAtrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) with significant effects on outcome. We aim to compare the left atrial (LA) diameter measurement with HCM-AF Score in predicting atrial fibrillation (AF) development in HCM. MethodsFrom the regional cohort of the Campania Region, Italy, 519 HCM patients (38% women, age45 ± 17 years) without history of AF, were enrolled in the study. The primary clinical endpoint was the development of AF, defined as at least 1 episode documented by ECG. ResultsDuring the follow-up (mean 8 ± 6, IQ range 2.5–11.2 years), 99 patients (19%) developed AF. Patients who developed AF were more symptomatic, had higher prevalence of ICD implantation, had larger LA diameter, greater left ventricular (LV) maximal wall thickness and LV outflow tract obstruction (p < 0.01). Both LA diameter and HCM-AF score were higher in patients who developed AF versus those who did not (LA diameter 49 ± 7 versus 43 ± 6 mm; HCM-AF score 22 ± 4 versus 19 ± 4; p < 0.0001); however, ROC curve analysis demonstrated that LA diameter had a significant greater area under the curve than HCM-AF Score (p < 0.0001). At 5 years follow-up, a LA diameter > 46 mm, showed a similar accuracy in predicting AF development of HCM-AF score ≥ 22, which identifies patients at high risk to develop AF. ConclusionOur analysis shows that LA diameter, a worldwide and simple echocardiographic measure, is capable alone to predict AF development in HCM patients.

Left atrial strain and long-term risk of atrial fibrillation in hypertrophic cardiomyopathy

Abstract Background The prevalence of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) patients is higher than in the general population, and it is associated with an increased risk of adverse outcomes, such as stroke, heart failure, and mortality. The left atrium (LA) plays an important role in maintaining normal cardiac function, and alterations in its structure and function can contribute to the development of AF. LA strain, a surrogate of LA remodeling, has been suggested a predictor of future AF. Purpose The aim of this study was to explore risk factors of new onset AF highlighting LA strain in patients with HCM. Methods Among a prospective cohort of 865 HCM patients collected at two large tertiary centers, 696 with adequate echocardiographic images to measure LA strain without a history of AF were included in the analysis. LA strain was measured on apical four-chamber view at initial evaluation using vendor-independent speckle-tracking software. The primary endpoint was new onset AF during 10 years after initial evaluation. Results The median age was 55.0 years and 74.3% were male. A median value of LA reservoir strain (LARS) was 26.2 % [interquartile range 20.4, 33.3]. Among the 696 patients, 66 had new onset AF 10 years, with a 10-year incidence of 15.8%. The unadjusted risk factors for new onset AF were previous stroke, non-apical HCM, family history of HCM, non-sustained ventricular tachycardia, obstructive HCM, extensive late gadolinium enhancement, larger LA diameter, larger LA volume, and lower LARS. LARS remained an independent predictor of new onset AF in multivariable analysis. The best cut-off value of LARS was 17.9% (hazard ratio 4.00, 95% confidence interval 2.44–6.55, p&amp;lt;0.001). Compared with LARS ≥17.9%, LARS &amp;lt;17.9% was significantly associated with a higher incidence of new onset AF, irrespective of presence of clinical risk factors (Figure 1) and LA enlargement (Figure 2). Conclusions In patients with HCM, low LA strain is an independent predictor of new onset AF.

Abstract 12822: Prediction of New-Onset Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy Using RNA-Sequencing of Plasma Small Non-Coding RNAs

Background: It is known that about 20% of patients with hypertrophic cardiomyopathy (HCM) develop atrial fibrillation (AF), which can lead to stroke and worsening of heart failure. The current clinical model to predict new-onset AF in patients with HCM (HCM-AF score) offers only modest accuracy. RNA-sequencing (RNA-Seq) can determine concentrations of thousands of small non-coding RNAs (sncRNAs) in plasma. Hypothesis/Aims: To test the hypothesis that RNA-Seq of plasma sncRNAs predicts new-onset AF in HCM. Methods: In this prospective, multi-center cohort study, we conducted RNA-Seq of 3,740 plasma sncRNAs at enrollment on 283 patients with HCM without a prior history of AF. The outcome was new-onset AF. We developed a sncRNA-Seq-based LASSO classification model (sncRNA-Seq-based model) to predict new-onset AF using data from one institution (training set, n=193). We tested the predictive ability of the model in independent samples from the other institutions (test set, n=90). We also developed a clinical model with LASSO using all components of HCM-AF score - i.e., left atrial diameter, age, age at HCM diagnosis, and New York Heart Association functional class ≥2. We then compared the area under the receiver-operating characteristic curve (AUC) between the sncRNA-Seq-based model and the clinical model in the test set. Results: During a median follow-up of 2.8 [1.9-5.1] years, 25 patients (13%) in the training set and 7 (8%) in the test set developed new-onset AF. Using the sncRNA-Seq-based model developed in the training set, the AUC to predict new-onset AF in the test set was 0.82 (95% confidence interval [CI] 0.71-0.94, Figure ). This model outperformed the clinical model (AUC 0.59; 95% CI 0.38-0.81; Delong’s test P=0.02). Conclusion: This study serves as the first to demonstrate the ability of plasma sncRNA-Seq to predict new-onset AF in patients with HCM. The prediction model may help physicians identify patients with HCM who are at high risk of developing new-onset AF.

Abstract 19180: Early Rhythm Control is Associated With Improved Outcomes in Hypertrophic Cardiomyopathy Patients With Atrial Fibrillation

Background: Atrial fibrillation in hypertrophic cardiomyopathy (HCM) patients is associated with worse outcomes with regards to stroke, heart failure hospitalization and death. Contemporary data on Rhythm control (RyC) strategies and outcomes in HCM patients is limited. Objectives: We aimed to assess the clinical characteristics of HCM patients with AF receiving RyC (antiarrhythmic drug and/or catheter ablation) vs no rhythm control (NRC) and compare clinical outcomes between the two groups. Methods: We analyzed the electronic health records of the University of Pittsburgh Medical Center, a large multi-hospital system, between 2010 and 2022. Differences between baseline demographics, cardiovascular risk factors, and comorbidity burden were evaluated with t tests. Adjusted Cox proportional hazards and Kaplan-Meier analyses were performed to evaluate associations between use of rhythm control and all-cause age-adjusted mortality. Results: A total of 552 patients with HCM and AF were analyzed, of which 118 received RyC and 434 NRC. The RyC group was relatively younger (age 64 vs 70), received initial evaluation by a cardiologist (70% vs 57%), had lower CHA2DS2VASC scores (mean 2.5 vs 3.1) and fewer comorbidities (mean Elixhauser scores 3.0 vs 4.7). There were no significant differences in either ejection fraction or left atrial diameter between the groups. Among RyC patients, 38 received catheter ablation and 80 received antiarrhythmic drug as the initial RyC strategy. Over a median follow up of 2.9 years (IQR 0.96-6.0), use of RyC was associated with decreased mortality after adjustment for age, Elixhauser score, and CHA2DS2VASC score (HR 0.54, 95% CI 0.30-0.95, p&lt;0.05, figure 1). Conclusion: Rhythm control in HCM and AF patients is associated with better outcomes as suggested by decreased overall mortality. Prospective studies are needed to establish the best RyC strategy in this cohort.

Atrioventricular nodal ablation is an effective management strategy for atrial fibrillation in patients with hypertrophic cardiomyopathy

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and can be challenging to manage. Atrioventricular nodal (AVN) ablation may be an effective management strategy for AF in these patients. The purpose of this study was to assess the efficacy of AVN ablation in HCM patients who have failed medical therapy and/or catheter ablation for AF. A multicenter study with retrospective analysis of a prospectively collated HCM registry was performed. AVN ablation patients were identified. Baseline characteristics and device and procedural indications were collected. Symptoms defined by New York Heart Association and European Heart Rhythm Association classification and echocardiographic findings during follow-up were assessed. Fifty-nine patients were included in the study. Indications for AVN ablation were 6 (10.2%) inappropriate implantable cardioverter-defibrillator shock, 35 (59.3%) ineffective rate control, and 18 (30.5%) to regularize rhythm for symptom improvement. During post-AVN ablation follow-up of 79.4 ± 61.1 months, left ventricular ejection fraction (LVEF) remained stable (pre-LVEF 48.9% ± 12.6% vs post-LVEF 50.1% ± 10.1%; P = .29), even in those without a cardiac resynchronization therapy (CRT) device (pre-LVEF 54.3% ± 8.0% vs post-LVEF 53.8% ± 8.0%; P = .65). Forty-nine patients (83.1%) reported an improvement in symptoms regardless of AF type (17/21 [81.0%] paroxysmal vs 32/38 [84.2%] persistent; P = 1.00), presence of baseline left ventricular impairment (22/26 [84.6%] LVEF ≤50% vs 27/33 [81.8%] LVEF ≥50%; P = 1.00) or CRT device (27/32 [84.4%] CRT vs 22/27 [81.5%] no CRT; P = 1.00). Symptoms improved in 16 patients (89.0%) who underwent AVN ablation to regularize rhythm. AVN ablation improved symptoms without impacting left ventricular function in the majority of patients. The data suggest that AVN ablation is an effective and safe management approach for AF in HCM and should be further evaluated in larger prospective studies.

PO-05-169 VENTRICULAR SCAR BY CARDIAC MRI IS A PREDICTOR OF ATRIAL FIBRILLATION IN HYPERTROPHIC CARDIOMYOPATHY

Atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) increases risk of stroke and mortality. The reported prevalence of AF in HCM ranges from 18% to 28%, which is higher than the general population; even after accounting for traditional risk factors including obesity, hypertension, and age. Several factors increase risk of AF in HCM including left atrial size and the presence of ventricular obstruction. However, there is paucity of data correlating ventricular late gadolinium enhancement (LGE) to the incidence of AF in HCM. Our study aims to investigate whether left ventricular LGE can predict the rate of AF in patients with HCM We identified all patients who were at least 18 years of age with HCM who underwent a cardiac MRI from May 2014 to March 2022. Patients’ baseline characteristics were compared between those who did and did not develop atrial fibrillation. Using a two-sample t-test, we compared the incidence of AF in the two groups. The rate of AF was further broken down with relation to left ventricular LGE and split into four categories: 0%, 1-5%, 6-14%, and ≥15%. A t-test or ANOVA (or their variance) were used for the continuous characteristics to compare the two groups and a Chi-square test was used for the categorical characteristics. A p-value of <0.05 was deemed as significant. Baseline characteristics were collected in 351 patients. Total AF prevalence was 39.6%. The rate of AF was 27.6% with 0% LGE, 38.5% with 1-5% LGE (p-value 0.101), 44.4% with 6-14% LGE (p-value 0.043), and 54.7% with ≥15% LGE (p-value 0.002). Furthermore, independent of age, percent LGE predicted AF especially at ≥15% (p-value 0.001). Our study suggests that left ventricular LGE independently predicts the incidence of AF in patients with HCM. The strongest correlation was identified at LGE ≥15% with 54.7% of this cohort developing AF. This has important implications regarding empiric anticoagulation in this group of patients with ≥15% LGE before they develop AF, especially since the CHADSVASc score has not been validated in HCM patients. Future studies are needed to assess if different anticoagulation strategies based on LGE percent have potential benefits in this patient population.

PO-05-141 ASSOCIATION OF INTERATRIAL BLOCK AND THE DEVELOPMENT OF ATRIAL FIBRILLATION AMONG PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY

Atrial fibrillation (AF) is the most common sustained arrhythmia among those with hypertrophic cardiomyopathy (HCM), affecting 1 in 5 patients. The combination of HCM and AF is associated with an increased risk of stroke, heart failure, and mortality. Interatrial block (IAB) is a distinct electrocardiographic (ECG) pattern describing conduction delay between the right and left atria through Bachmann’s bundle. IAB has been identified as a predictor of AF across several disease states including congestive heart failure, valvular disease, and cardiac amyloidosis. To evaluate the association of IAB ECG findings with the development of AF among patients with HCM. We conducted a retrospective cohort study of adults with HCM who received care at our center from 8/17/1997 to 3/18/2021. Patients were included if they had an ECG reading prior to their AF diagnosis. We used multivariable logistic regression to identify whether IAB ECG findings (partial, advanced, or atypical) were associated with increased odds of AF in this patient population, after adjusting for potential covariates. Among 574 patients with HCM, 199 (34.7%) developed AF. The majority of AF was paroxysmal (75.4%). The average age in our cohort was 48 years and 220 (58.8%) were male. Among those who developed AF, 132 (66.3%) had an IAB ECG finding vs. 142 (37.9%) who did not develop AF. The most common abnormality was partial IAB (n=162, 28.2%). After adjusting for covariates, both partial and advanced IAB were significantly associated with the development of AF [aOR 4.15 (2.17 – 7.99; p <0.001) and aOR 5.39 (2.30 – 12.60; p <0.001), respectively]. Our analysis suggests that IAB ECG findings can serve as an important marker to identify those at risk of AF in HCM. IAB has demonstrated clinical prognostic significance and should prompt rigorous screening for AF in HCM patients. Our results should be validated by larger prospective studies.Tabled 1Baseline characteristics (N = 574)Atrial fibrillation (n = 199)No atrial fibrillation (n = 375)Age in years, mean (SD)47 (1.3)48 (0.9)Male, (%)144 (72.4)231 (61.6)BMI ≥ 30 kg/m2, (%)118 (59.3)175 (46.6)Paroxysmal atrial fibrillation, (%)Persistent atrial fibrillationPermanent atrial fibrillationLone episode atrial fibrillationNA150 (75.4)11 (5.5)19 (9.5)4 (2.0)15 (7.5)NANYHA functional class I, (%)NYHA functional class IINYHA functional class IIINYHA functional class IV48 (24.1)70 (35.2)80 (40.2)1 (0.50)129 (34.4)128 (34.1)118 (31.5)0 (0)Implantable cardioverter-defibrillator, (%)19 (9.5)27 (7.2)Systolic anterior motion, (%)155 (77.9)262 (69.9)Normal ECGPartial IABAdvanced IABAtypical IAB67 (33.7)84 (42.2)30 (15.1)18 (9.0)233 (62.1)78 (20.8)25 (6.7)39 (10.4)P-wave duration, ms, mean (SD)126.4 (1.5)117.7 (0.8)Ejection fraction ≥ 50%, (%)194 (97.5)374 (99.7)Logistic regression of ECG finding (N = 574)Odds ratio, 95% confidence intervalAdjusted odds ratio, 95% confidence interval∗The multivariable logistic regression adjusted for the following prespecified covariates: p-wave duration, gender, age, NYHA functional class, BMI ≥30 kg/m2, the presence of systolic anterior motion of mitral valveNormal ECGPartial IABAdvanced IABAtypical IABREF3.75 (2.48 – 5.65; p <0.001)4.17 (2.30 – 7.58; p <0.001)1.52 (0.81 – 2.85; p = 0.196)REF4.15 (2.17 – 7.99; p <0.001)5.39 (2.30 – 12.60; p <0.001)1.87 (0.93 – 3.75; p = 0.080)∗ The multivariable logistic regression adjusted for the following prespecified covariates: p-wave duration, gender, age, NYHA functional class, BMI ≥30 kg/m2, the presence of systolic anterior motion of mitral valve Open table in a new tab

PO-02-157 IMPACT OF ATRIAL FIBRILLATION ON QUALITY OF LIFE IN HYPERTROPHIC CARDIOMYOPATHY

In hypertrophic cardiomyopathy (HCM) atrial fibrillation (AF) has been historically described as unrelenting, a driver for heart failure, with a decisive impact on quality of life. AF treatment has been deemed less effective in HCM due to high rates of AF recurrence. However, AF has predominantly been characterized from physicians perspective and there is no data on impact on patient reported outcome measures (PROMs). To evaluate the impact of AF on PROMs in HCM. PROMs were collected using the Atrial Fibrillation Severity Scale (AFSS) and Kansas City Cardiomyopathy Questionnaire overall summary (KCCQ-OS) reflecting symptom burden and quality of life in 250 consecutive HCM patients. Among the 250 patients, 51 (20%) were diagnosed with AF at 56±10 years of age, 6.5±5.5 years prior to evaluation and reported health status. At evaluation, 45 of the 51 AF patients (88%) were in sinus rhythm, and 6 in AF (12%) including 5 in permanent AF. Each of the 51 patients required AF treatment for symptoms: 27 (53%) solely with medications (17 with AV nodal medications and 10 on antiarrhythmic drugs); and 24 (47%) with AF ablation (16 with catheter ablation and 8 surgical Cox-Maze IV at time of myectomy). Of the 24 AF ablation patients, 15 (63%) had recurrent AF including 6 (25%) requiring multiple ablation procedures. After most recent ablation, AF burden was reported as infrequent ≤1 episode per month in 17 (71%), including 10 with ≤1 episode/year. 75% had AFSS symptom score consistent with mild symptoms, and 91% had KCCQ-OS with mild or no disability. There was no difference in either KCCQ-OS or AFSS in patients with and without AF recurrence after ablation (p=0.68). The 27 patients treated solely with medications each had recurrent AF episodes on current therapy, but 15 (56%) reported infrequent AF burden ≤1 per month including 11 with ≤1 episode/year. With treatment, 67% had AFSS symptom score consistent with mild symptoms and 82% had KCCQ-OS with mild or no disability. There was no difference in KCCQ-OS in the 51 HCM patients with AF compared to 199 patients without AF (p=0.2). Recurrent AF in HCM is common despite treatment, however episodes tend to be infrequent. With treatment, the majority of patients with AF have no or mild symptom burden. These data support that despite recurrent AF episodes after treatment, quality of life metrics are not significantly impaired for most HCM patients.

Catheter ablation of atrial fibrillation in hypertrophic cardiomyopathy: A proportional meta-analysis and systematic review of single-arm studies

Atrial fibrillation (AF) is the most common arrhythmia in patients with hypertrophic cardiomyopathy (HCM). Limited data exists about the efficacy and clinical outcomes of AF ablation in HCM. The purpose of this meta-analysis was to evaluate the role of catheter-based ablation for treatment of AF in patients with HCM. PubMed, SCOPUS, Web of Science, Embase, Cochrane library, and ClinicalTrials.gov were searched for studies discussing outcomes of catheter-based ablation for AF in patients with HCM. Two reviewers independently screened studies and extracted relevant data. Incidence rate estimates from individual studies underwent logit transformation to calculate the weighted summary proportion under the random effect model. A total of 19 reports met the inclusion criteria (1183 patients). The single ablation procedure was successful in 39% patients. Up to 34% patients underwent a repeat ablation. About 41% patients in normal sinus rhythm after successful AF ablation received postprocedure antiarrhythmic drug (AAD) therapy. Patients undergoing successful AF ablation experienced a significant improvement in the New York Heart Association functional class (standardized mean difference -1.03; 95% confidence interval -1.23 to -0.83; P < .00001). AF ablation appears to be safe and feasible in patients with HCM. Freedom from AF after undergoing successful ablation is associated with significant improvement in heart failure symptoms.

Association of Types of Sleep Apnea and Nocturnal Hypoxemia with Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy

Data regarding the association between sleep apnea (SA) and atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) are still limited. We aim to investigate the association of both types of SA, obstructive sleep apnea (OSA) and central sleep apnea (CSA), and nocturnal hypoxemia with AF in HCM. A total of 606 patients with HCM who underwent sleep evaluations were included. Logistic regression was used to assess the association between sleep disorder and AF. SA was presented in 363 (59.9%) patients, of whom 337 (55.6%) had OSA and 26 (4.3%) had CSA. Patients with SA were older, more often male, had a higher body mass index, and more clinical comorbidities. Prevalence of AF was higher in patients with CSA than patients with OSA and without SA (50.0% versus 24.9% and 12.8%, p < 0.001). After adjustment for age, sex, body mass index, hypertension, diabetes mellitus, cigarette use, New York Heart Association class and severity of mitral regurgitation, SA (OR, 1.79; 95% CI, 1.09-2.94) and nocturnal hypoxemia (higher tertile of percentage of total sleep time with oxygen saturation < 90% [OR, 1.81; 95% CI, 1.05-3.12] compared with lower tertile) were significantly associated with AF. The association was much stronger in the CSA group (OR, 3.98; 95% CI, 1.56-10.13) than in OSA group (OR, 1.66; 95% CI, 1.01-2.76). Similar associations were observed when analyses were restricted to persistent/permanent AF. Both types of SA and nocturnal hypoxemia were independently associated with AF. Attention should be paid to the screening of both types of SA in the management of AF in HCM.

Abstract 14237: Left Atrial Dynamics Predict Incident Atrial Fibrillation in Hypertrophic Cardiomyopathy

Introduction: Atrial fibrillation (AF) is the most common arrhythmia in patients with hypertrophic cardiomyopathy (HCM) and is associated with an 8-fold increased risk of stroke. However, the ability to predict incident AF remains limited. Methods: At a single referral center, we identified HCM patients with paired transthoracic echocardiograms (TTEs) performed at least 12-months apart and both prior to a diagnosis of AF. Baseline clinical characteristics and the occurrence of incident AF was obtained from a clinical registry and the electronic medical record. Comprehensive analysis of TTEs was performed by an experienced reader who was blinded to clinical events and included total atrial emptying fraction (LA EF) and its individual components, including LA volume at end-systole. Changes in parameters over time were determined by comparing results between each TTE. Univariate and multivariate regression, Cox proportional hazard, and Kaplan-Meier methods were used to analyze factors associated with the subsequent incidence of AF. Results: We studied 202 patients (mean age 45 years, 42% female, 27% hypertensive, 39% with sarcomere mutation, 37% NYHA II or greater). Of all factors examined, the initial LA EF, as well as the rate of LA remodeling as defined by the change in LA end-systolic volume over time, were most significantly predictive of AF development (Figure 1). These results were robust to multivariate regression with other factors significant in HCM (Figure 1C), including baseline LA diameter. Conclusions: Reduced LA function (the LA EF) and increased rate of LA dilation predict incident AF in HCM. Future studies are needed to identity factors associated with adverse LA dynamics in HCM and whether these can be mitigated with pharmacotherapy.

Left atrial remodelling after septal myectomy is associated with a reduced 5-year risk of atrial fibrillation in hypertrophic cardiomyopathy

Abstract Background Left atrial diameter (LAD) is an established predictor of atrial fibrillation (AF) and adverse outcomes in hypertrophic cardiomyopathy (HCM). However, the impact of LAD remodelling after surgical myectomy on the development of late onset AF is still poorly understood. Purpose To investigate the association between LAD remodelling and new occurrence of AF in the first five years after surgical myectomy in a large patient population with HCM. Methods 1177 HCM patients without a history of AF, subjected to surgical myectomy at two referral centres between 2001 and 2020 were retrospectively reviewed. Paired echocardiographic studies before and shortly after surgical myectomy were available in 894 (76%) patients and 889 (75%) patients had complete LAD measurements, defined as the anteroposterior diameter at end-systole from parasternal long axis view. LAD was considered normal when ≤40mm. Late onset AF was determined as AF documented between one month and 5 years follow up after myectomy. Patients were grouped as having normal LAD pre- and post-myectomy (group 1), enlarged pre-myectomy LAD but normal post-myectomy LAD (group 2), and those with enlarged LAD post-myectomy (group 3). Cox proportional hazards models were applied to evaluate the impact of LAD on late onset AF. Results Late onset AF was detected in 63 (7%) patients, 56% male, with an incidence of 1%/year. Patients with AF were older (56±13 vs. 52±14 years, p=0.03), had a larger post-surgery LAD (44±7 vs. 41±6 mm, p&amp;lt;0.001) and a lower left ventricular ejection fraction (58±6 vs. 61±6%, p=0.002) compared to patients without AF. Postoperative left ventricular maximal wall thickness (14±4 mm vs. 15±4mm, p=0.53), left ventricular outflow tract obstruction (6% vs. 8%, p=0.49) or moderate/severe mitral regurgitation (13% vs. 9%, p=0.29) were similar between patients with and without late onset AF. Among the 227 patients in group 1, late onset AF occurred in only 5 (3%), in comparison to 8 (5%) of 182 patients in group 2, and in 36 (10%) of the 480 patients in group 3 (p=0.006). Using group 1 as reference, the hazard ratio for developing AF was 2.1 (95% CI 0.7–6.5, p=0.15) for patients in group 2 and 3.5 (95% CI 1.4–9.4, p=0.005) for patients in group 3. Conclusion In our study we were able to show that the overall post-myectomy 5-year risk for developing AF was 1%/year. Normal LAD and reverse LAD remodelling correlated with a lower risk for developing late onset AF, whereas a higher risk was associated with enlarged post-myectomy LAD. These results highlight the possible clinical benefit of LAD remodelling after myectomy in reducing late onset AF. Funding Acknowledgement Type of funding sources: None.

Ischaemic events in hypertrophic cardiomyopathy patients with and without atrial fibrillation: a systematic review and meta-analysis.

Hypertrophic cardiomyopathy predisposes to acute cerebrovascular events including ischaemic stroke, transient ischaemic attack and systemic thromboembolism. Atrial fibrillation confers even higher risk. We aim to report the incidence of these complications and to investigate the impact of atrial fibrillation on the ischaemic risk in patients with hypertrophic cardiomyopathy. A literature search was performed on PubMed, Scopus, Embase/Ovid and Cochrane library from inception to 20th March 2021. We compared the incidence of ischaemic strokes, transient ischaemic attack, non-specified thromboembolism events and systemic thromboembolism in hypertrophic cardiomyopathy patients with or without atrial fibrillation. Non-specified thromboembolism events in our paper referred to thromboembolic events whereby types were not specified in the studies. Meta-analysis was performed using StataSE 16 software, and heterogeneity was assessed using I2 test. A total of 713 studies were identified. Thirty-five articles with 42,570 patients were included. The pooled incidence of stroke/ transient ischaemic attack was 7.45% (95% confidence interval [CI] 5.80-9.52, p < 0.001) across 24 studies with a total of 37,643 hypertrophic cardiomyopathy patients. Atrial fibrillation significantly increased the risk of total stroke/ transient ischaemic attack (Risk Ratio 3.26, 95% CI 1.75-6.08, p < 0.001, I2 = 76.0). The incidence of stroke/ transient ischaemic attack was 9.30% (95% CI 6.64-12.87, p = 0.316) in the apical hypertrophic cardiomyopathy subgroup. Concomitant atrial fibrillation in hypertrophic cardiomyopathy increases the risk of thromboembolic events including ischaemic stroke and transient ischaemic attack. The apical subgroup shows a similar risk of acute cerebrovascular events as the overall hypertrophic cardiomyopathy population.

The predictive value of fast semi-automated left atrial long-axis strain analysis for atrial fibrillation in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) patients are closely related to LA functional impairment. Left atrial (LA) strain provides more insight into LA function. The study aimed to investigate the left atrial dysfunction of HCM patients by rapid semi-automatic method and determine the predictive value of left atrial long-axis strain (LAS) for atrial fibrillation (AF). We enrolled 372 HCM patients and 100 healthy participants to assess the LA functional parameters. LAS was obtained by semi-automated tracking of the distance between the mid-posterior point of LA wall which is defined as the intersection of the LA long axis and the posterior wall, and the origins of the mitral valve. The inferior and anterior mitral valve annular insertion points on the 2-chamber view and the lateral and septal insertion points on the 4-chamber view were chosen as the origins of the mitral valve. The clinical outcome was defined as detecting the onset of AF. The LA strain values were analyzed as 20.8 ± 7.48% for εs, 9.81 ± 5.09% for εe, and 10.91 ± 4.24% for εa in HCM patients, which decreased significantly compared with normal controls. Significant correlations were detected between LV functional parameters and LA strain. During a median follow-up of 61 months, 44 (11.8%) patients developed AF. In the Cox regression analysis, LA strain was identified as a significant predictor of the onset of AF. HCM patients had impairment of LA strain before LA enlargement and reduced EF. LA-LAS can be used as a predictive value for predicting the occurrence of AF in HCM patients. • Fast semi-automated long-axis strain analysis by CMR is feasible and effective for evaluating the LA longitudinal function. • Hypertrophic cardiomyopathy patients show significant impairment of left atrial strain before LA enlargement. • The left atrial long-axis strain was an independent predictor of atrial fibrillation in hypertrophic cardiomyopathy.

Ventricular Septal Myectomy Decreases Long-Term Risk for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) and is an important cause of morbidity and embolic stroke. The impact of outflow obstruction and the influence of surgical septal myectomy on the development of new-onset AF has not been well described. Consecutive patients with HCM without previous AF were followed for 5.0 ± 3.6years for new-onset AF, including 717 with obstruction who did not undergo surgical myectomy (outflow gradients ≥30mm Hg at rest or after provocation), 555 with nonobstructive HCM (outflow gradients &lt;30mm Hg), and 503 who underwent surgical myectomy. Patients with obstructive HCM who did not undergo myectomy had a 1.5-fold increased risk for new-onset AF compared with nonobstructive HCM (26% vs 16% at 10years, hazard ratio = 0.69, p=0.02). Patients who underwent myectomy had more advanced heart failure (95% vs 18% New York Heart Association class III, p &lt;0.001) and had larger left atrium dimension (42±7 vs 41±7mm; p &lt;0.01) as compared with patients with obstructive HCM who did not undergo myectomy. However, after myectomy, the risk of new-onset AF was significantly lower than nonoperated obstructive (17% vs 26% at 10years, p=0.04) and no different from the risk of AF in patients with nonobstructive HC (hazard ratio 0.95, p=0.81).In conclusion, patients with HCM with outflow obstruction are at a higher risk for AF compared with patients with nonobstructive HCM. However, after surgical myectomy, the risk for new-onset AF is substantially reduced. In addition to the known benefits of myectomy to permanently relieve outflow tract obstruction and mitral regurgitation, reverse heart failure symptoms, and increase longevity, myectomy is now shown to decrease susceptibility to AF in HCM.

Left atrioventricular coupling index in hypertrophic cardiomyopathy and risk of new-onset atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background In patients with hypertrophic cardiomyopathy (HCM) accurate risk stratification for new onset atrial fibrillation (AF) has important prognostic implications. Left atrioventricular coupling index (LACI) has been recently associated with the occurrence of AF in patients without history of cardiovascular disease. Purpose The objective of this study was to investigate the association between LACI and new onset AF in HCM patients and its incremental value over conventional left atrial (LA) parameters. Methods A total of 373 HCM patients without history of AF (48 ± 17 years, 66% men) were evaluated by transthoracic echocardiography. LACI was defined by the ratio of the LA end-diastolic volume divided by the LV end-diastolic volume. The cut-off value for LACI (≥40%) to identify LA-left ventricular (LV) uncoupling was chosen based on the risk excess of new-onset AF described with a spline curve analysis. Cox proportional hazard models were used to evaluate the association between LACI and the occurrence of AF. Results The median LACI was 38% (interquartile range: 24-56) and LA-LV uncoupling (LACI ≥40%) was observed in 171 (45.8%) patients. During a mean follow-up of 11.0 ± 5.6 years, 118 subjects (31.6%) developed new-onset AF. The cumulative event-free survival at 10 years was 53% for patients with LA-LV uncoupling (LACI ≥40%) versus 94% for patients without LA-LV uncoupling (LACI &amp;lt;40%) (p &amp;lt; 0.0001; Figure 1). Multivariable analysis showed an independent association between new-onset AF and LA maximum volume indexed (LAVImax) (hazard ratio [HR], 1.03; 95% CI, 1.02–1.04), LA minimum volume indexed (LAVImin) (HR, 1.04; 95% CI, 1.03–1.05), LA emptying fraction (HR, 0.97; 95% CI, 0.96–0.98) and LACI (HR, 1.02; 95% CI, 1.01–1.02; all p &amp;lt; 0.0001). The inclusion of LACI in the multivariate model provided larger improvement in the risk stratification for new-onset AF, as compared to conventional LA parameters (Figure 2). Furthermore, the likelihood ratio test demonstrated incremental value of LACI assessment on the top of the multivariate model including LAVImin to predict new-onset AF (p = 0.02), while the addition of LAVImin did not improve the risk discrimination of the multivariate model including LACI (p = 0.36). Conclusion Greater LACI, indicative of LA-LV uncoupling, was independently associated with the occurrence of new-onset AF in patients with HCM and demonstrated a stronger risk discrimination power compared to conventional LA parameters. This simple ratio may be easily implemented in clinical practice to improve risk stratification for new-onset AF in HCM. Abstract Figure. Incident AF according to LACI Abstract Figure.

Hypertrophic Cardiomyopathy and Atrial Fibrillation: A Review.

Hypertrophic cardiomyopathy (HCM) is an inherited cardiological condition that exhibits various clinical symptoms. The leading cause of atrial fibrillation (AF) in patients with HCM is advanced diastolic dysfunction and left atrial dilatation and remodeling. In addition to the gradual symptomatic and functional decline caused by AF, there is an increased risk of thromboembolic disease and mortality, especially if there is a rapid ventricular rate or obstruction of the left ventricular outflow tract. The mainstay of management of AF in HCM is a combination of non-pharmacological lifestyle and risk factor modification, long-term anticoagulation, and rhythm control with anti-arrhythmic medications, septal ablation, and radiofrequency catheter ablation. This article has examined the development of AF in HCM, its clinical symptomatology, and its impact, highlighting its management and the mortality associated with AF in HCM.

Abstract 9755: Impact of Outflow Obstruction and Septal Myectomy on Long Term Risk of New Onset Atrial Fibrillation in Hypertrophic Cardiomyopathy

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), with patients having a 4 to 6 fold greater likelihood of developing AF as compared to the general population, and is an important cause of morbidity, impaired quality of life and embolic stroke in HCM. The impact of outflow obstruction and the influence of surgical septal myectomy on the development of new-onset AF has not been well described. Aim: To characterize the risk of new-onset AF in nonobstructive and obstructive HCM and compare to AF risk in patients after myectomy. Methods: 1767 consecutive HCM patients without prior AF history, seen at the Tufts HCM Institute between 2004 and 2019, including 712 with obstruction (outflow gradients ≥ 30mmHg at rest or following provocation) who did not undergo invasive septal reduction therapy (SRT), 552 with nonobstructive HCM (outflow gradients &lt; 30mmHg), and 503 who underwent surgical myectomy were followed for an average of 4.3 ±4.2 years for new-onset symptomatic AF. Isolated post-operative episodes of AF, i.e., occurring within the first 3 months after myectomy, were excluded from analysis. Results: Patients with obstructive HCM who did not undergo SRT had a 1.5-fold increased risk for new-onset AF as compared to nonobstructive HCM (rate onset of 2.8%/year vs.1.7%/year, p=0.04), with freedom from AF at 10-years of 72% in obstructive patients. Patients undergoing myectomy were older (52 ± 15 vs. 50 ± 15 years; p&lt;0.01), had larger LA dimension (42 ± 7 vs 40 ± 6mm; p&lt;0.01), and higher HCM-AF risk scores (22 ± 3.5 vs. 19 ± 3.8; p&lt;0.01) as compared to nonobstructive HCM. However, despite a higher predicted risk for new-onset AF at time of myectomy (2.7%/year vs. 1.5%/year), after myectomy the risk of new onset AF was no different from patients with nonobstructive HCM (hazard ratio 0.9; rate of onset of 1.8%/year vs. 1.7%/year; p=.73), with freedom from AF at 10-years of 83% post-myectomy. Conclusions: Patients with obstructive HCM have a higher risk of AF as compared to nonobstructive HCM. After myectomy risk of new-onset AF is substantially reduced, such that risk is no different from patients with nonobstructive HCM. These data demonstrate efficacy of myectomy in decreasing long term risk of AF in obstructive HCM.

Alteration of Serum Biomarkers in Patients with Hypertrophic Cardiomyopathy with and Without Atrial Fibrillation

Aim: We sought to determine the relationship between presence of atrial fibrillation (AF) and serum biomarkers, including native thiol (antioxidant), disulphide/native thiol ratio, Hs-CRP and high-sensitivity Troponin-I (Hs-TnI) in hypertrophic cardiomyopathy (HCM). Materials & methods: We enrolled consecutive 121 HCM outpatients without AF and 40 HCM outpatients with AF. A 12-lead electrocardiogram, transthoracic echocardiography and 24/48-h ambulatory rhythm monitoring were performed for all patients. Fasting venous blood samples were taken from all study patients to measure serum thiol-disulphide homeostasis, Hs-CRP and Hs-TnI. Results: Serum-native thiol was lower and disulphide/native thiol ratio was more oxidized in HCM patients with AF (p<0.001). Also, HCM patients with AF had higher Hs-TnI and Hs-CRP than no-AF HCM patients. Disulphide/native thiol ratio, serum-native thiol, age, NYHA functional class≥III, and advanced diastolic dysfunction were independently associated with the presence of AF in HCM. Conclusion: In addition to clinical and echocardiographic findings, oxidative stress is also associated with AF in HCM patients.

Electrophysiological and Structural Remodeling of the Atria in a Mouse Model of Troponin-I Mutation Linked Hypertrophic Cardiomyopathy: Implications for Atrial Fibrillation.

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disorder affecting one in 500 of the general population. Atrial fibrillation (AF) is the most common arrhythmia in patients with HCM. We sought to characterize the atrial electrophysiological and structural substrate in young and aging Gly203Ser cardiac troponin-I transgenic (HCM) mice. At 30 weeks and 50 weeks of age (n = 6 per strain each group), the left atrium was excised and placed on a multi-electrode array (MEA) for electrophysiological study; subsequent histological analyses and plasma samples were analyzed for biomarkers of extracellular matrix remodeling and cell adhesion and inflammation. Wild-type mice of matched ages were included as controls. Young HCM mice demonstrated significantly shortened atrial action potential duration (APD), increased conduction heterogeneity index (CHI), increased myocyte size, and increased interstitial fibrosis without changes in effective refractory periods (ERP), conduction velocity (CV), inflammatory infiltrates, or circulating markers of extracellular matrix remodeling and inflammation. Aging HCM mice demonstrated aggravated changes in atria electrophysiology and structural remodeling as well as increased circulating matrix metalloproteinases (MMP)-2, MMP-3, and VCAM-1 levels. This model of HCM demonstrates an underlying atrial substrate that progresses with age and may in part be responsible for the greater propensity for AF in HCM.