Impact of atrial fibrillation on the clinical course of apical hypertrophic cardiomyopathy

Incremental prognostic value of left atrial strain in apical hypertrophic cardiomyopathy: a cardiovascular magnetic resonance study

OBJECTIVES

This study aimed to evaluate the prognostic value of left atrial (LA) strain in patients with apical hypertrophic cardiomyopathy (ApHCM), as assessed by cardiac magnetic resonance (CMR) imaging.

METHODS

Four hundred and five consecutive patients with ApHCM who underwent CMR examination were retrospectively included. The study endpoint included all-cause death, heart transplant, aborted sudden cardiac death, hospitalization for heart failure, stroke, and new-onset atrial fibrillation (AF).

RESULTS

After a median follow-up of 97 months, 75 patients (18.5%) reached the endpoint. Patients were divided into two groups based on the median LA reservoir strain of 29.4%. The group with lower LA reservoir strain had thicker maximum wall thickness, greater late gadolinium enhancement extent, and smaller end-diastolic volume index, stroke volume index, and cardiac index (all p < 0.02). For LA parameters, this subgroup showed greater diameter and volume index and worse ejection fraction, reservoir, conduit, and booster strain (all p < 0.001). In the multivariable model, age (HR 1.88, 95% CI: 1.06-3.31, p = 0.030), baseline AF (HR 2.95, 95% CI: 1.64-5.28, p < 0.001), LA volume index (LAVi) (HR 2.07, 95% CI: 1.21-3.55, p = 0.008) and LA reservoir strain (HR 2.82, 95% CI: 1.51-5.26, p = 0.001) were all associated with the outcome. Adding LAVi and LA reservoir strain in turn to the multivariable model (age and baseline AF) resulted in significant improvements in model performance (p < 0.001).

CONCLUSION

In ApHCM patients, LA reservoir strain is independently associated with cardiovascular risk events and has an incremental prognostic value.

CLINICAL RELEVANCE STATEMENT

Left atrial reservoir strain measured by cardiac magnetic resonance is highly correlated with the prognosis of apical hypertrophic cardiomyopathy and has potential incremental value in the prognosis of major adverse cardiac events.

KEY POINTS

Left atrial (LA) strain parameters may be useful for risk stratification and treatment of apical hypertrophic cardiomyopathy (ApHCM). Apical hypertrophic cardiomyopathy (ApHCM) is independently associated with LA morphology and function. Cardiac MR examination, especially its feature-tracking technology, provides the possibility to prognosticate ApHCM at an early stage.

Clinical and Genetic Risk Factors Predict Atrial Fibrillation on the Basis of Hypertrophic Cardiomyopathy

BACKGROUND

Clinical and genetic predispositions are significant in predicting atrial fibrillation (AF); however, their role in patients with hypertrophic cardiomyopathy (HCM) remains unclear. This study aims to elucidate the impact of clinical and genetic risk factors on the development of AF in patients with and without HCM.

METHODS AND RESULTS

This retrospective analysis involved data from the UK Biobank cohort. Participants were divided into 3 groups based on their validated polygenic risk score for AF: the bottom 10% as low risk, the top 10% as high risk, and the rest as intermediate risk. We assessed the incidence of AF and cardiovascular complications and analyzed its predictors, including genetic risk. We examined 1180 patients with HCM (mean age, 61.1±7.1; 63.0% men) and 476 238 participants without HCM (mean age, 57.0±8.1; 45.3% men). During the 11.6-year follow-up period, the age- and sex-adjusted AF incidence rates for the low, intermediate, and high genetic risk groups were 2.4, 3.6, and 5.4 per 100 person-years in participants with HCM and 0.2, 0.5, and 1.0 per 100 person-years in participants without HCM, respectively. Genetic risk, evaluated as a continuous variable using polygenic risk score, was a less significant predictor of AF in the HCM group (hazard ratio [HR], 1.35 [95% CI, 1.21-1.49]) than in non-HCM group (HR, 1.57 [95% CI, 1.56-1.59]; P=0.005 for interaction). A high genetic risk was significantly associated with the risk of cardiovascular complications in both groups.

CONCLUSIONS

Genetic predisposition is associated with the development of AF and cardiovascular complications in people with and without HCM; this association was weaker in the HCM group.

Predicting New-Onset Atrial Fibrillation in Hypertrophic Cardiomyopathy: A Review

Hypertrophic cardiomyopathy (HCM) is a condition characterized by left ventricular hypertrophy, with physiopathological remodeling that predisposes patients to atrial fibrillation (AF). The electrocardiogram is a basic diagnostic tool for evaluating heart electrical activity. Key electrocardiographic features that correlate with AF onset are P-wave duration, P-wave dispersion, and electromechanical delay in left atrium (LA). Clinical markers, including age, body mass index, New York Heart Association functional class, and heart failure symptoms, are also strong predictors of AF in HCM. Risk scores have been created using multiple variables to better predict AF development. Increasing knowledge of genetic subsets in HCM and cardiovascular pathology in general has provided novel insight in this context. Structural and mechanical LA remodeling, including fibrosis, altered LA function, and changes in atrial size, further contribute to AF risk prediction. Cardiovascular magnetic resonance (CMR) and echocardiographic measures provide accurate information about atrial structure and function. Machine learning models are increasingly being utilized to refine risk prediction, incorporating a wide range of variables. This review highlights the multifaceted approach required to understand and predict AF development in HCM. Such an approach is imperative to enhance prognostic accuracy and improve the quality of life of these patients. Further research is necessary to refine patient outcomes and develop customized management strategies for HCM-associated AF.

Cryoballoon Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: From the Korean Cryoballoon Ablation Registry

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) occurs in more than 20% of hypertrophic cardiomyopathy (HCM) patients, further increasing the risk of stroke. Although radiofrequency catheter ablation in AF patients with HCM has been performed, data on cryoballoon ablation (CBA) in HCM patients are limited. We evaluated the efficacy and safety of CBA in HCM patients with AF.

METHODS

The study included 2,649 patients with AF from the Korean CBA registry database with follow-up >12 months after de novo CBA. The primary efficacy outcome was recurrence of atrial tachyarrhythmias (ATs) ≥30s after a 3-month blanking period.

RESULTS

Totals of 1,176 paroxysmal AF (44.4%) and 1,473 persistent atrial fibrillation (PeAF, 55.6%) patients (mean age 61.7 years; 76.7% men) underwent de novo CBA. Compared to non-HCM patients (n=2,590), those with HCM (n=59) had larger left atrium and higher prevalence of heart failure, previous stroke or transient ischemic attack, and PeAF. Procedure-related complications were not statistically different between the 2 groups. During a mean follow-up period of 638±308 days, 875 (33.0%) patients experienced recurrence of ATs (845 [32.6%] non-HCM patients and 30 [50.8%] HCM patients) (p=0.01). The overall AT-free survival rate at 2 years was 45.9% in HCM group and 63.3% in non-HCM group, respectively (p=0.014), whereas there was no significant difference between the two groups in PeAF.

CONCLUSIONS

CBA may be an effective rhythm control treatment for patients with AF and HCM, with an AT-free survival rate of approximately 50% at 2-year follow-up and low procedure-related complications.

Prediction of new-onset atrial fibrillation in patients with hypertrophic cardiomyopathy using plasma proteomics profiling

AIMS

Atrial fibrillation (AF) is the most common sustained arrhythmia among patients with hypertrophic cardiomyopathy (HCM), increasing symptom burden and stroke risk. We aimed to construct a plasma proteomics-based model to predict new-onset AF in patients with HCM and determine dysregulated signalling pathways.

METHODS AND RESULTS

In this prospective, multi-centre cohort study, we conducted plasma proteomics profiling of 4986 proteins at enrolment. We developed a proteomics-based machine learning model to predict new-onset AF using samples from one institution (training set) and tested its predictive ability using independent samples from another institution (test set). We performed a survival analysis to compare the risk of new-onset AF among high- and low-risk groups in the test set. We performed pathway analysis of proteins significantly (univariable P < 0.05) associated with new-onset AF using a false discovery rate (FDR) threshold of 0.001. The study included 284 patients with HCM (training set: 193, test set: 91). Thirty-seven (13%) patients developed AF during median follow-up of 3.2 years [25-75 percentile: 1.8-5.2]. Using the proteomics-based prediction model developed in the training set, the area under the receiver operating characteristic curve was 0.89 (95% confidence interval 0.78-0.99) in the test set. In the test set, patients categorized as high risk had a higher rate of developing new-onset AF (log-rank P = 0.002). The Ras-MAPK pathway was dysregulated in patients who developed incident AF during follow-up (FDR < 1.0 × 10-6).

CONCLUSION

This is the first study to demonstrate the ability of plasma proteomics to predict new-onset AF in HCM and identify dysregulated signalling pathways.

Genetic testing in early-onset atrial fibrillation

Atrial fibrillation (AF) is a globally prevalent cardiac arrhythmia with significant genetic underpinnings, as highlighted by recent large-scale genetic studies. A prominent clinical and genetic overlap exists between AF, heritable ventricular cardiomyopathies, and arrhythmia syndromes, underlining the potential of AF as an early indicator of severe ventricular disease in younger individuals. Indeed, several recent studies have demonstrated meaningful yields of rare pathogenic variants among early-onset AF patients (∼4%-11%), most notably for cardiomyopathy genes in which rare variants are considered clinically actionable. Genetic testing thus presents a promising opportunity to identify monogenetic defects linked to AF and inherited cardiac conditions, such as cardiomyopathy, and may contribute to prognosis and management in early-onset AF patients. A first step towards recognizing this monogenic contribution was taken with the Class IIb recommendation for genetic testing in AF patients aged 45 years or younger by the 2023 American College of Cardiology/American Heart Association guidelines for AF. By identifying pathogenic genetic variants known to underlie inherited cardiomyopathies and arrhythmia syndromes, a personalized care pathway can be developed, encompassing more tailored screening, cascade testing, and potentially genotype-informed prognosis and preventive measures. However, this can only be ensured by frameworks that are developed and supported by all stakeholders. Ambiguity in test results such as variants of uncertain significance remain a major challenge and as many as ∼60% of people with early-onset AF might carry such variants. Patient education (including pretest counselling), training of genetic teams, selection of high-confidence genes, and careful reporting are strategies to mitigate this. Further challenges to implementation include financial barriers, insurability issues, workforce limitations, and the need for standardized definitions in a fast-moving field. Moreover, the prevailing genetic evidence largely rests on European descent populations, underscoring the need for diverse research cohorts and international collaboration. Embracing these challenges and the potential of genetic testing may improve AF care. However, further research-mechanistic, translational, and clinical-is urgently needed.

Clinical and genetic associations of asymmetric apical and septal left ventricular hypertrophy

Aims

Increased left ventricular mass has been associated with adverse cardiovascular outcomes including incident cardiomyopathy and atrial fibrillation. Such associations have been studied in relation to total left ventricular hypertrophy, while the regional distribution of myocardial hypertrophy is extremely variable. The clinically significant and genetic associations of such variability require further study.

Methods and results

Here, we use deep learning-derived phenotypes of disproportionate patterns of hypertrophy, namely, apical and septal hypertrophy, to study genome-wide and clinical associations in addition to and independent from total left ventricular mass within 35 268 UK Biobank participants. Using polygenic risk score and Cox regression, we quantified the relationship between incident cardiovascular outcomes and genetically determined phenotypes in the UK Biobank. Adjusting for total left ventricular mass, apical hypertrophy is associated with elevated risk for cardiomyopathy and atrial fibrillation. Cardiomyopathy risk was increased for subjects with increased apical or septal mass, even in the absence of global hypertrophy. We identified 17 genome-wide associations for left ventricular mass, 3 unique associations with increased apical mass, and 3 additional unique associations with increased septal mass. An elevated polygenic risk score for apical mass corresponded with an increased risk of cardiomyopathy and implantable cardioverter-defibrillator implantation.

Conclusion

Apical and septal mass may be driven by genes distinct from total left ventricular mass, suggesting unique genetic profiles for patterns of hypertrophy. Focal hypertrophy confers independent and additive risk to incident cardiovascular disease. Our findings emphasize the significance of characterizing distinct subtypes of left ventricular hypertrophy. Further studies are needed in multi-ethnic cohorts.

Novel insight into the role of A-kinase anchoring proteins (AKAPs) in ischemic stroke and therapeutic potentials

Ischemic stroke, a devastating disease associated with high mortality and disability worldwide, has emerged as an urgent public health issue. A-kinase anchoring proteins (AKAPs) are a group of signal-organizing molecules that compartmentalize and anchor a wide range of receptors and effector proteins and have a major role in stabilizing mitochondrial function and promoting neurodevelopmental development in the central nervous system (CNS). Growing evidence suggests that dysregulation of AKAPs expression and activity is closely associated with oxidative stress, ion disorder, mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in ischemic stroke. However, the underlying mechanisms remain inadequately understood. This review provides a comprehensive overview of the composition and structure of A-kinase anchoring protein (AKAP) family members, emphasizing their physiological functions in the CNS. We explored in depth the molecular and cellular mechanisms of AKAP complexes in the pathological progression and risk factors of ischemic stroke, including hypertension, hyperglycemia, lipid metabolism disorders, and atrial fibrillation. Herein, we highlight the potential of AKAP complexes as a pharmacological target against ischemic stroke in the hope of inspiring translational research and innovative clinical approaches.

A Case of New-Onset Atrial Tachyarrhythmias With Apical Hypertrophic Cardiomyopathy and Bronchiectasis in a Very Elderly Patient: A Therapeutic Dilemma

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease that is genetically transmitted as an autosomal dominant trait. Even apical HCM (ApHCM) induces atrial fibrillation (AF) based on underlying left ventricle (LV) diastolic dysfunction, where anticoagulation therapy is recommended. However, anticoagulation for AF in patients at high risk of bleeding is a double-edged sword. A 98-year-old woman living in a nursing home presented to our hospital with sudden-onset dyspnea and palpitation persisting for two hours. The patient had a history of apical HCM and bronchiectasis. An electrocardiogram showed a regular tachycardia with a heart rate of 130 bpm, suggesting atrial flutter with 2:1 atrioventricular conduction. Intravenous verapamil (5 mg) resulted in the conversion into AF, and subsequent cibenzoline (70 mg) failed to restore sinus rhythm. Given the impossibility of continuous anticoagulation, electrical cardioversion was planned. Electrical cardioversion was successful in converting AF into sinus rhythm. Given the very high risk of hemoptysis, anticoagulation was avoided. This case gives an insight into how to manage a practical therapeutic problem, which is the coexistence of AF and bronchiectasis. A variety of individual factors should be considered for clinical decision-making and management of patients with concomitant HCM and AF.

A pilot study for risk stratification of ventricular tachyarrhythmia in hypertrophic cardiomyopathy with routine echocardiography parameters

Ventricular tachyarrhythmia (VTA) are frequent arrhythmias in patients with hypertrophic cardiomyopathy (HCM). Representing a major risk factor for sudden cardiac death, Holter ECG at first clinical presentation appears insufficient. This study aims to investigate the ability of routinely obtained parameters associated with myocardial remodeling in stratifying for VTA in HCM. In this monocentric analysis, patients with HCM underwent 12-channel electrocardiography and echocardiography, including tissue doppler imaging. The study's primary endpoint was the documentation of non-sustained and sustained ventricular tachycardia-summarized as ventricular tachyarrhythmias (VTA) on Holter ECG or active devices. The occurrence of VTA was exploratory. Based on our collective, we developed a risk model regarding VTA. Of 140 HCM patients, 38 (27.1%) had an episode of VTA. Patients with VTA were likelier to have a history of atrial fibrillation (p < 0.001), a thicker interventricular septum (p < 0.001) and lower peak systolic mitral annular velocity (p < 0.001). The parameters were independently associated with endpoint in univariate and multivariate logistic regression. We created a logistic equation and calculated a cut-off value. The resulting ROC curve revealed a discriminative ability with AUC of 0.80 (sensitivity, 63%; specificity, 88%). Our risk model including these widely available parameters is able to distinguish low and high-risk of VTA in patients with HCM.

Atrial fibrillation: comorbidities, lifestyle, and patient factors

Modern anticoagulation therapy has dramatically reduced the risk of stroke and systemic thromboembolism in people with atrial fibrillation (AF). However, AF still impairs quality of life, increases the risk of stroke and heart failure, and is linked to cognitive impairment. There is also a recognition of the residual risk of thromboembolic complications despite anticoagulation. Hence, AF management is evolving towards a more comprehensive understanding of risk factors predisposing to the development of this arrhythmia, its' complications and interventions to mitigate the risk. This review summarises the recent advances in understanding of risk factors for incident AF and managing these risk factors. It includes a discussion of lifestyle, somatic, psychological, and socioeconomic risk factors. The available data call for a practice shift towards a more individualised approach considering an increasingly broader range of health and patient factors contributing to AF-related health burden. The review highlights the needs of people living with co-morbidities (especially with multimorbidity), polypharmacy and the role of the changing population demographics affecting the European region and globally.

The efficacy and safety of direct oral anticoagulants compared with vitamin K antagonist in patients with hypertrophic cardiomyopathy and atrial fibrillation

BACKGROUND

The benefit-risk profile of direct oral anticoagulants (DOAC) therapy in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) has not been well established yet. This study aimed to evaluate the efficacy and safety of DOAC compared with vitamin K antagonists (VKA) in patients with HCM and AF.

METHODS

PubMed, EMBASE, the Cochrane Library, and clinicaltrials.gov were searched to identify studies comparing DOAC with VKA in patients with HCM and AF. The primary endpoint was thromboembolic events. The relative risks and standard errors were pooled by random-effect models using the generic inverse variance method.

RESULTS

Seven observational studies involving 9395 patients were included in this meta-analysis. Compared to the VKA group, the DOAC group displayed a similar risk of thromboembolic events [RR (95%CI): 0.93 (0.73-1.20), p = 0.59] and ischemic stroke [RR (95%CI): 0.65 (0.33-1.28), p = 0.22]. The incidence of major bleeding was comparable between the two groups [RR (95%CI): 0.75 (0.49-1.15), p = 0.19]. Meanwhile, DOAC therapy was superior to VKA therapy in reducing the incidences of all-cause death [RR (95%CI): 0.44 (0.35-0.55), p < 0.001], cardiovascular death [RR (95%CI): 0.41 (0.22-0.75), p = 0.004], and intracranial hemorrhage [RR (95%CI): 0.42 (0.24-0.74), p = 0.003].

CONCLUSION

In patients with HCM and AF, DOAC therapy was similar to VKA therapy in reducing the risk of thromboembolic events, without increasing bleeding risk. In addition, the DOAC group displayed significant advantages in reducing mortality and intracranial hemorrhage compared with the VKA group. Further randomized controlled trials are needed to provide more evidence for DOAC therapy in this population.

Multimodality Imaging in Patients with Hypertrophic Cardiomyopathy and Atrial Fibrillation

Ventricular hypertrophy is associated with diastolic dysfunction, resulting in increased left atrial (LA) pressure, enlargement, fibrosis, and decreased LA function. Hypertrophic cardiomyopathy (HCM) is characterized by myocyte disarray, myocardial fibrosis, and hypertrophy. Notably, a thickened and noncompliant LV results in the impairment of diastolic function. These conditions promote LA remodeling and enlargement, which contribute to developing and maintaining atrial fibrillation (AF). AF is an atrial arrhythmia that occurs frequently in HCM, and evaluating the morphology and physiology of the atrium and ventricle is important for treatment and prognosis determination in HCM patients with AF. In addition, it provides a clue that can predict the possibility of new AF, even in patients not previously diagnosed with AF. Cardiac magnetic resonance (CMR), which can overcome the limitations of transthoracic echocardiography (TTE), has been widely used traditionally and even enables tissue characterization; moreover, it has emerged as an essential imaging modality for patients with HCM. Here, we review the role of multimodal imaging in patients with HCM and AF.

High-Risk Apical Hypertrophic Cardiomyopathy Requiring an Implantable Cardioverter-Defibrillator: A Case Report of an Overlooked Etiology

Apical hypertrophic cardiomyopathy is a rare variant of hypertrophic cardiomyopathy characterized by abnormal heart muscle thickening, specifically affecting the left ventricle's apex. Classically revealing both giant T-wave inversions in the precordial leads of an electrocardiogram and a spade-like configuration of the left ventricular cavity on ventriculograms, the diagnosis of the apical variant has evolved with cardiac magnetic resonance imaging. Despite being well known among East Asian populations, the diagnosis of apical hypertrophic cardiomyopathy is often underestimated and overlooked among American patients due to the non-specific nature of echocardiography. In this case report, we present the diagnosis of apical hypertrophic cardiomyopathy in a middle-aged African American male with chronic palpitations. The diagnosis was confirmed using cardiac magnetic resonance imaging, which revealed extensive myocardial fibrosis. Ultimately, the patient was treated with an implantable cardioverter-defibrillator. Our case aims to enhance the understanding and facilitate the recognition and management of apical hypertrophic cardiomyopathy, particularly among non-Asian individuals. Current challenges revolve around robust risk stratification strategies for patients at high risk for sudden cardiac death that require device therapy.

Yamaguchi syndrome - An updated review article of electrocardiographic and echocardiographic findings

Apical hypertrophic cardiomyopathy (ApHCM) is thought to be an uncommon variant of hypertrophic cardiomyopathy (HCM). This article is a literature review focusing on the characteristic electrocardiogram (EKG) and 2D echocardiogram findings as currently there are no specific ACC/AHA/ESC guidelines set as diagnostic criteria for ApHCM.

Prognostic effect of atrial fibrillation on survival in patients with hypertrophic cardiomyopathy: a meta-analysis

OBJECTIVE

To systematically evaluate the prognostic impact of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM).

METHODS

The Chinese and English databases (PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure, and Wanfang database were systematically searched to include observational studies on the prognosis of AF in cardiovascular events or death in patients with HCM; these were evaluated using Revman 5.3.

RESULTS

After systematic search and screening, a total of 11 studies with a high study quality were included in this study. Meta-analysis showed that patients with HCM accompanied by AF had a higher risk of all-cause death (odds ratio [OR] = 2.75; 95% confidence interval [CI]: 2.18-3.47; P < 0.001), heart-related death (OR = 2.62; 95%CI: 2.02-3.40; P < 0.001), sudden cardiac death (OR = 7.09; 95%CI: 5.77-8.70; P < 0.001), heart-failure-related death (OR = 2.04; 95%CI: 1.24-3.36; P = 0.005), and stroke death (OR = 17.05; 95%CI: 6.99-41.58; P < 0.001) compared with patients with HCM without AF.

CONCLUSION

Atrial fibrillation is a risk factor for adverse survival outcomes in patients with HCM, and aggressive interventions are needed in this population to avoid the occurrence of adverse outcomes.

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.

Very long-term prognosis in patients with hypertrophic cardiomyopathy: a longitudinal study with a period of 20 years

AIMS

We aim to clarify the prognosis on patients with hypertrophic cardiomyopathy (HCM) for a follow-up period of more than 10 years.

METHODS AND RESULTS

We retrospectively analysed 102 consecutive patients with HCM diagnosed by 31 December 2000. Complete and detailed clinical records were obtained for 93 (91%) of the 102 patients. Sixty-three (68%) of the 93 patients were men, and the mean age of the patients at the initial evaluation was 51.5 ± 13.0 years. During the mean follow-up period of 19.6 ± 8.1 years (median 20.1 years), HCM-related deaths occurred in 20 patients (21% [1.1%/year]). HCM-related adverse events (including HCM-related deaths and nonfatal HCM-related events: hospitalization for heart failure, embolic stroke admission, and sustained ventricular tachycardia with haemodynamic instability or appropriate implantable cardioverter-defibrillator discharge) occurred in 45 patients (48%). The first HCM-related adverse events occurred in approximately 20% of the patients in every decade, the first decade to the third decade, from the initial evaluation. Forty-seven patients (51%) had documentation of atrial fibrillation at the last follow-up. There were seven patients in the end-stage HCM group at the initial evaluation, and 22 patients (24%) had progression to end-stage HCM during the follow-up period.

CONCLUSIONS

In our cohort of patients, HCM-related mortality was relatively favourable. However, approximately half of the patients suffered from HCM-related adverse events during the follow-up period of 20 years. It is important for HCM patients to be carefully followed up over the long-term because HCM is a lifelong disease.

Absent fourth heart sound as a marker of adverse events in hypertrophic cardiomyopathy with sinus rhythm

BACKGROUND

Patients with hypertrophic cardiomyopathy (HCM) in sinus rhythm commonly show the fourth heart sound (S4). The lack of S4 may be a marker of impaired atrial function in HCM patients with sinus rhythm.

METHODS AND RESULTS

This retrospective study consisted of 47 patients with HCM who had undergone phonocardiography and a cardiopulmonary exercise test. The primary outcome was a composite of cardiac death, stroke, hospitalization for worsening heart failure, and newly developed atrial fibrillation (AF). S4 was detected in 38 of 43 patients with sinus rhythm (88%). Peak oxygen consumption was the highest in 38 sinus rhythm patients with S4 (23.6 ± 5.6 mL/kg/min), middle in five sinus rhythm patients without S4 (19.3 ± 6.7 mL/kg/min), and lowest in four patients with AF (15.7 ± 3.3 mL/kg/min, p = 0.01). After a median of 40.5 months, the incidence of the primary outcome was higher in patients without S4 than in those with S4 (33% vs. 8%; hazard ratio, 6.17; 95% confidence interval, 1.02 - 37.4; p = .04) and higher in sinus rhythm patients without S4 than in those with S4 (60% vs. 8%; hazard ratio, 12.05; 95% confidence interval, 2.31 - 71.41; p = .007).

CONCLUSIONS

The absence of S4 on phonocardiography was associated with impaired exercise tolerance and adverse cardiac events in HCM patients with sinus rhythm.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants in patients with hypertrophic cardiomyopathy with non-valvular atrial fibrillation

Hypertrophic cardiomyopathy (HCM) patients with nonvalvular atrial fibrillation (AF) have an increased risk of suffering thromboembolic events. Vitamin K antagonists (VKA) are recommended as therapy but there is still limited data regarding the efficacy of prescribing non-vitamin K antagonist oral anticoagulants (NOACs). This retrospective study investigates the effectiveness and safety of NOAC administration in patients with HCM and AF. A total of 124 patients with HCM and AF on an oral anticoagulant therapy were recruited between January 2015 and December 2019; these patients were followed up until March 31, 2020. Kaplan-Meier analysis was used to compare the clinical outcomes in patients treated with NOACs versus warfarin. The Cox model was used to estimate the risk of clinically relevant bleeding. Our study included 124 patients, of which 48 (38.7%) received warfarin and 76 (61.3%) received NOACs. Survival analysis showed the patients undergoing NOACs had a lower risk of clinically relevant bleeding (log-rank P = 0.039) over a period of 53.6 months. The median time in therapeutic range (TTR) score was 50% (interquartile range: 40.43 to 57.08%). A total of nine patients (18.75%) had a good TTR with a median score of 66.35% (interquartile range: 64.58 to 77.75%). The incidence of death by all causes, cardiovascular death and thromboembolism were similar between NOAC and warfarin-treated patients (log-rank P = 0.239, log-rank P = 0.386, and log-rank P = 0.257, respectively). Patients treated with NOACs showed a significant reduction in the risk of clinical (P = 0.011) and gastrointestinal bleeding (P = 0.032). Cox multiple regression analysis showed age (HR 1.13, 95% CI 1.03-1.24; P = 0.013) and warfarin therapy (HR 7.37, 95% CI 1.63-33.36; P = 0.010) were independent predictors of clinically relevant bleeding. Compared to warfarin, NOACs were associated with a lower incidence of clinically relevant bleeding in HCM patients with AF, as demonstrated by the similar incidence of death by all causes, cardiovascular death and thromboembolic events.

2021 Focused update of the 2017 consensus guidelines of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation

The consensus of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation (AF) has been published in 2017 which provided useful clinical guidance for cardiologists, neurologists, geriatricians, and general practitioners in Asia-Pacific region. In these years, many important new data regarding stroke prevention in AF were reported. The Practice Guidelines subcommittee members comprehensively reviewed updated information on stroke prevention in AF, and summarized them in this 2021 focused update of the 2017 consensus guidelines of the APHRS on stroke prevention in AF. We highlighted and focused on several issues, including the importance of AF Better Care (ABC) pathway, the advantages of non-vitamin K antagonist oral anticoagulants (NOACs) for Asians, the considerations of use of NOACs for Asian patients with AF with single 1 stroke risk factor beyond gender, the role of lifestyle factors on stroke risk, the use of oral anticoagulants during the "coronavirus disease 2019" (COVID-19) pandemic, etc. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician's decision remains the most important factor in the management of AF.

Ischemic Stroke in Patients With Hypertrophic Cardiomyopathy According to Presence or Absence of Atrial Fibrillation

BACKGROUND AND PURPOSE

Patients with hypertrophic cardiomyopathy (HCM) have high risk of ischemic stroke (IS), especially if atrial fibrillation (AF) is present. Improvements in risk stratification are needed to help identify those patients with HCM at higher risk of stroke, whether AF is present or not.

METHODS

This French longitudinal cohort study from the database covering hospital care from 2010 to 2019 analyzed adults hospitalized with isolated HCM. A logistic regression model was used to construct a French HCM score, which was compared with the HCM Risk-CVA and CHA₂DS₂-VASc scores using c-indexes and calibration analysis.

RESULTS

In 32 206 patients with isolated HCM, 12 498 (38.8%) had AF, and 2489 (7.7%) sustained an IS during follow-up. AF in patients with HCM was independently associated with a higher risk for death (hazard ratio, 1.129 [95% CI, 1.088-1.172]), cardiovascular death (hazard ratio, 1.254 [95% CI, 1.177-1.337]), IS (hazard ratio, 1.210 [95% CI, 1.111-1.317]), and other major cardiovascular events. Independent predictors of IS in HCM were older age, heart failure, AF, prior IS, smoking and poor nutrition (all P<0.05). For the HCM Risk-CVA score, CHA₂DS₂-VASc score and a French HCM score, all c-indexes were 0.65 to 0.70, with good calibration. Among patients with AF, the CHA₂DS₂-VASc score had marginal improvement over the HCM Risk-CVA score but was less predictive compared with the French HCM score (P=0.001). In patients without AF, both HCM Risk-CVA score and the French HCM score had significantly better prediction compared with CHA₂DS₂-VASc (both P<0.0001). Decision curve analysis demonstrated that the French HCM score had the best clinical usefulness of the 3 tested risk scores.

CONCLUSIONS

Patients with HCM have a high prevalence of AF and a significant risk of IS, and the presence of AF in patients with HCM was independently associated with worse outcomes. A simple French HCM score shows good prediction of IS in patients with HCM and clinical usefulness, with good calibration.

Deciphering hypertrophic cardiomyopathy with electrocardiography

The comprehensive assessment of patients with hypertrophic cardiomyopathy is a complex process, with each step concurrently focusing on confirmation of the diagnosis, differentiation between sarcomeric and non-sarcomeric disease (phenocopy), and prognostication. Novel modalities such as genetic testing and advanced imaging have allowed for substantial advancements in the understanding of this condition and facilitate patient management. However, their availability is at present not universal, and interpretation requires a high level of expertise. In this setting, electrocardiography, a fast and widely available method, still retains a significant role in everyday clinical assessment of this population. In our review, we follow a stepwise approach for the interpretation of each electrocardiographic segment, discussing clinical implications of electrocardiographic patterns in sarcomeric disease, their value in the differential diagnosis from phenocopies, and impact on patient management. Outlining the substantial amount of information to be obtained from a simple tracing, we exhibit how electrocardiography is likely to remain an integral diagnostic tool in the future as well.

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.

Atrial fibrillation and the risk of sudden cardiac arrest in patients with hypertrophic cardiomyopathy - A nationwide cohort study

BACKGROUND

Hypertrophic cardiomyopathy (HCM), affecting 0.2% of the population, is the leading cause of sudden cardiac arrest (SCA). Incident atrial fibrillation (AF) is associated with an increased risk of SCA in general population. To determine whether AF is associated with an increased risk of SCA in patients with HCM.

METHODS

This nationwide cohort study analyzed data from Registry for Catastrophic Illness, which encompassed almost 100% of the patients with HCM in Taiwan from 1996 to 2013. Follow-up and data analysis ended December 31, 2013. The main outcome was physician-adjudicated SCA, defined as death from a sudden, pulseless condition presumed due to a ventricular tachyarrhythmia. The secondary outcome was non-sudden cardiac death (NSCD), which was heart failure death, stroke death and non-HCM related death. We used Cox proportional hazards models to assess the association between AF and SCA/NSCD, adjusting for baseline demographic and cardiovascular risk factors.

FINDINGS

A total 10,910 subjects participated in this study with mean age of 62 years. Among enrolled subjects, 1,169 (10.7%) developed AF, which was independently associated with elder age, female sex, and history of heart failure (HF) hospitalization. During follow-up (median, 8.5 years and 2th to 7th interquartile range, 3.6 to 16.5 years), 371 SCA (166 in AF and 205 in non-AF group) and 797 NSCD (417 in AF and 380 in non-AF group) events occurred. The crude incidence rates of SCA were 12.45/1000 person-years (with AF) and 3.57/1000 person-years (without AF). The crude incidence rates for NSCD were 31.29/1000 person-years (with AF) and 6.63/1000 person-years (without AF). The multivariable hazard ratios (HRs) (95% CI) of AF for SCA and NSCD were 3.633 (2.756-4.791) and 2.086 (1.799-2.418), respectively. Furthermore, among the etiologies of NSCD, subjects with AF was at most risk of stroke-related death (HR, 6.609; 95% CI, 3.794-9.725).

INTERPRETATION

Incident AF is associated with an increased risk of SCA and NSCD in the HCM population. Early detection of AF may provide more comprehensive risk stratification of SCD in HCM population. Because of underuse of oral anticoagulants and the absence of primary prevention ICD therapy in our cohort, the application of our findings was limited for the general HCM population in the current clinical practice.

FUNDING

None.

Thromboembolism in Patients with Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disease, which has a marked heterogeneity in clinical expression, natural history, and prognosis. HCM is associated with a high prevalence of thromboembolic events (stroke and systemic embolic events), even if taking no account of atrial fibrillation (AF), leading to unexpected disability and death in patients of all ages. Several risk factors of thromboembolism such as AF, greater age, left atrial diameter, heart failure and others have been confirmed in patients with HCM. Conventional thromboembolic predictive models were estimated by several trials in HCM population but it turned out to be unsatisfactory. Based on those previous explorations, researchers tried to modify or develop novel models suitable for HCM population in thromboembolism prediction. In consideration of catastrophic advent events of thromboembolism, current guidelines have recommended life-long anticoagulant therapy after a single short AF. Therefore, early identification of risk factors for thromboembolism, accurate risk stratification, timely preventive measures and aggressive management may help to avoid serious adverse thromboembolic events in HCM population.

Preoperative Statin Use Is Associated With Less Postoperative Atrial Fibrillation After Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy

The present study aims to investigate whether preoperative statin use is associated with less postoperative atrial fibrillation occurrence after septal myectomy in patients with hypertrophic obstructive cardiomyopathy (HOCM). Clinical data of consecutive patients with HOCM who underwent septal myectomy between February 2009 and May 2019 at our institution was retrospectively reviewed. The cohort was divided into 2 groups according to the status of preoperative statin use (statin group vs no statin group). Logistic regression was used to explore associations of clinical variables with postoperative atrial fibrillation occurrence. A total of 1307 patients with HOCM underdoing septal myectomy were included in the present study, with 109 patients in the statin group and 1198 in the no statin group. Among 322 patients (24.6%) developing postoperative atrial fibrillation, 21 cases (19.3%) occurred in the statin group, while 301 cases (25.1%) were in the no statin group (P = 0.202). After propensity score matching with confounding variables at baseline, 91 paired patients were included in the matched cohort. Postoperative atrial fibrillation developed in 17 (18.7%) and 38 (41.8%) in the statin and no statin groups, respectively (P = 0.001). Preoperative statin use was associated with less postoperative atrial fibrillation occurrence (odds ratio 0.220, 95% confidence interval 0.083-0.588, P<0.003). The present study suggested that preoperative statin use was associated with less postoperative atrial fibrillation occurrence after septal myectomy in patients with HOCM. This finding may provide clues for subsequent prospective study to investigate this clinical issue.

B-type natriuretic peptide and outcome in patients with apical hypertrophic cardiomyopathy

BACKGROUND

Although elevated B-type natriuretic peptide (BNP) levels predict outcome in patients with hypertrophic cardiomyopathy (HCM), the association between BNP levels and outcome in patients with the apical phenotype of HCM remains unclear. We evaluated the impact of elevated BNP levels on outcome in a cohort of apical HCM patients.

METHODS

Among 432 HCM patients, 144 with an apical phenotype were examined. Plasma BNP levels were measured at the time of the initial evaluation.

RESULTS

The median (interquartile range) BNP level at initial evaluation in these patients was 188.5 (72.0-334.4) pg/mL. During a median follow-up period of 9.5 years, 34 patients experienced HCM-related adverse outcomes, including 2 patients with sudden death, 5 with appropriate implantable defibrillator shocks, 3 with stroke-related death, 8 with non-fatal stroke, and 16 with heart failure hospitalization. Receiver operating characteristic (ROC) curve analysis of the prognostic value of BNP for the combined endpoint gave an area under the ROC curve of 0.756, and optimal BNP cut-off point of 226.0pg/mL. Patients with high BNP levels (≥226.0pg/mL) were at significantly greater risk of the combined endpoint (log-rank p<0.001) than patients with low BNP levels. Multivariable analysis that included BNP levels and potential confounders showed that high BNP levels were an independent determinant of the combined endpoint (adjusted hazard ratio: 3.71; p=0.002).

CONCLUSIONS

Measuring BNP may help stratify the risk of HCM-related adverse outcome in apical HCM patients.

Hypertrophic cardiomyopathy: the future of treatment

Hypertrophic cardiomyopathy (HCM) is a heterogeneous genetic disorder most often caused by sarcomeric mutations resulting in left ventricular hypertrophy, fibrosis, hypercontractility, and reduced compliance. It is the most common inherited monogenic cardiac condition, affecting 0.2% of the population. Whereas currently available therapies for HCM have been effective in reducing morbidity, there remain important unmet needs in the treatment of both the obstructive and non-obstructive phenotypes. Novel pharmacotherapies directly target the molecular underpinnings of HCM, while innovative procedural techniques may soon offer minimally-invasive alternatives to current septal reduction therapy. With the advent of embryonic gene editing, there now exists the potential to correct underlying genetic mutations that may result in disease. This article details the recent developments in the treatment of HCM including pharmacotherapy, septal reduction procedures, mitral valve manipulation, and gene-based therapies.

Echocardiographic Evaluation of Left Atrial Function to Discriminate Non-Valvular Atrial Fibrillation Development in Patients with Apical Hypertrophic Cardiomyopathy

BACKGROUND

Data is limited on baseline left atrial (LA) myocardial mechanics between apical hypertrophic cardiomyopathy (ApHCM) patients who develop non-valvular atrial fibrillation (NVAF) during follow-up and those who do not.

METHODS

This retrospective study investigated the clinical outcomes of consecutive patients newly diagnosed with ApHCM between August 2011 and July 2014 who were followed-up for at least 3 years. The patients underwent 12-lead surface electrocardiography and/or 24-hour Holter electrocardiography at least once a year. The patients were divided into two groups, namely those who did or did not exhibit NVAF during follow-up, respectively. The baseline clinical and echocardiographic data of the two groups were compared.

RESULTS

Twenty patients were studied, five of whom were lost to follow-up. Of the remaining 15 ApHCM patients, seven developed NVAF. No differences were observed in the clinical characteristics of the two groups. However, for the echocardiographic data, the NVAF development group exhibited a larger LA volume and impaired LA reservoir, conduit and booster functions. The NVAF development group also showed lower peak LA strain and stiffer left atrium. The LA volume, function, global strain and stiffness were all statistically associated with NVAF development. Among these parameters, a LA conduit function of ≤ 24.9% was found to be the best parameter to discriminate NVAF development.

CONCLUSIONS

The baseline LA function was impaired in the ApHCM patients who subsequently developed NVAF during follow-up. A LA conduit function of ≤ 24.9% was strongly associated with NVAF development.

Thromboembolic Outcomes of Different Anticoagulation Strategies for Patients with Atrial Fibrillation in the Setting of Hypertrophic Cardiomyopathy: A Systematic Review

Objective

Limited data is available assessing the efficacy and safety of different anticoagulation (AC) strategies for prevention of thromboembolic events, major bleeding, and all-cause mortality in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF). In this systematic review, we conducted a literature search to examine the possible association between different AC strategies and prevention of these adverse outcomes.

Methods

Scientific databases (PubMed, EMBASE, and Scopus) were searched using relevant medical subject headings and keywords to retrieve studies published through September of 2019. Studies assessing the outcomes of interest in patients with HCM and AF receiving AC, no AC as well as direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) were selected.

Results

This review identified 14 observational studies evaluating thromboembolic events by AC strategies in 8,479 participants with concomitant HCM and AF. The use of AC was associated with a lower pooled incidence rate of total thromboembolic events at 9.5% (112 events in 1,175 patients) compared to 22.1% with no AC (108 events in 489 patients). In addition, the use of DOACs was associated with a lower pooled incidence rate of thromboembolic events at 4.7% (169 events in 3,576 patients) compared to 8.7% with VKAs (281 events in 3,239 patients). Furthermore, the use of DOACs compared to VKAs was associated with a lower pooled incidence rate of major bleeding and all-cause mortality at 3.8% (136 events in 3,576 patients) versus 6.8% (220 events in 3,239 patients) and 4.1% (124 events in 3,008 patients) versus 16.1% (384 events in 2,380 patients), respectively.

Conclusions

AC of patients with concomitant HCM and AF was associated with a lower incidence of thromboembolic events when compared to antiplatelet therapy or no treatment. Treatment with DOACs was also associated with a lower incidence of thromboembolic events, major bleeding, and all-cause mortality when compared to VKAs.

Apical myectomy for patients with hypertrophic cardiomyopathy and advanced heart failure

OBJECTIVE

In patients with apical hypertrophic cardiomyopathy, extensive apical hypertrophy may reduce left ventricular end-diastolic volume and contribute to diastolic dysfunction, angina, and ventricular arrhythmias. Transapical myectomy to augment left ventricular cavity size can increase stroke volume and decrease left ventricular end-diastolic pressure. In this study, we describe early outcomes of patients with apical hypertrophic cardiomyopathy after transapical myectomy and compare survival with that of patients with hypertrophic cardiomyopathy listed for heart transplantation.

METHODS

Between September 1993 and March 2017, 113 symptomatic patients with apical hypertrophic cardiomyopathy underwent transapical myectomy. Clinical information, echocardiographic data, and follow-up were reviewed. With the use of a national database, survival was compared with that of patients with hypertrophic cardiomyopathy listed for heart transplantation.

RESULTS

In the surgical cohort, median (interquartile range) age was 50.8 (39.3-60.7) years, and 49 (43%) were male. Preoperatively, 108 patients (96%) were in New York Heart Association class III/IV. All patients underwent transapical myectomy. There were 4 (4%) deaths within 30 days of operation. At last follow-up, 76% of patients reported improvement in symptoms, and 3 patients (3%) subsequently underwent cardiac transplantation for recurrent heart failure. The estimated 1-, 5-, and 10-year survivals were 96%, 87%, and 74%, respectively. Survival appeared superior to patients with hypertrophic cardiomyopathy listed for heart transplant.

CONCLUSIONS

Apical myectomy is beneficial in severely symptomatic patients with apical hypertrophic cardiomyopathy. Early risk of the procedure is low, and approximately 76% maintain clinical improvement with resolution of symptoms. Long-term survival appears better than for patients listed for heart transplantation.

Calculated Risk for Sudden Cardiac Death in Patients with Apical Versus Nonobstructive Nonapical Hypertrophic Cardiomyopathy

There are limited and conflicting data regarding the prognosis of patients with apical hypertrophic cardiomyopathy (HC) and their risk for sudden cardiac death (SCD). We used data from a single tertiary center for comparing the clinical course and the calculated risk for SCD in patients with nonobstructive apical HC (apical HC) versus patients with nonobstructive, nonapical HC (NONA HC). The 5-year SCD risk was calculated based on the HC risk-SCD tool. A total of 109 patients were included in the cohort of whom 44 (40%) patients were diagnosed with apical HC. The majority of patients were males with a median age at diagnosis of 40 years (interquartile range 26, 59 years). Patients with apical HC had a significant lower calculated 5-year risk for SCD compared with patients with NONA HC (2.65 ± 2.2% vs 4.00 ± 3.5%, respectively, p = 0.017), primarily due to a lower incidence of familial SCD (20% vs 43% respectively, p = 0.014). Only 9% of patients with apical HC had a calculated risk of >6% (implantable cardioverter-defibrillator recommended), as compared with 23% of patients with NONA HC. During a median follow-up of 1,018 days (interquartile range 546, 1449 days), apical HC patients tended to develop less malignant ventricular arrhythmia episodes compared with NONA HC patients (0% vs 7.7%, respectively, p = 0.060). In conclusion, apical HC patients have a lower calculated risk of SCD compared with NONA HC patients, mainly due to a lower incidence of family history of SCD. Thus, apical HC should be considered a form of HC less prone to SCD.

Renin-angiotensin-aldosterone blockade reduces atrial fibrillation in hypertrophic cardiomyopathy

OBJECTIVES

Atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) is associated with increased mortality, mainly mediated by increased thromboembolic events and progressive heart failure. Many studies suggested inhibition of renin-angiotensin-aldosterone system (RAAS) could reduce new AF in various clinical conditions. However, evidence concerning the effects of RAAS inhibitors on AF prevention remains unclear in HCM. Our study is to investigate whether treatment with ACE inhibitors (ACEIs) or angiotensin-receptor blockers (ARBs) could lower the risk of new AF in HCM.

METHODS

We conducted a retrospective study including subjects diagnosed HCM between January 1997 and December 2013 by using a nationwide database covering almost all Taiwanese from National Health Research Institute. All participants, aged 18 or older, had no ACEIs or ARBs exposure or AF diagnosis before enrolment. Propensity score matching and multivariate Cox hazard regression were employed to estimate the risk of new AF occurrence.

RESULTS

Total 18 266 subjects were included in the analysis with median follow-up duration 8.13 years. Patients taking ACEIs or ARBs are associated with lower risk of developing new AF than those without taking neither of medications (3.16% vs 5.65%, relative risk 0.56 (95% CI 0.49 to 0.64), HR 0.572 (95% CI 0.480 to 0.683)). The correlation is more prominent with longer ACEIs or ARBs treatment (HRs from T1 to T3: 0.741, 0.579, 0.337, P<0.001). These results remain consistent after propensity score adjustment.

CONCLUSION

In patients with HCM, lower risk of new AF is observed in patients treated with either ACEIs or ARBs compared with those receiving neither of these medications.