Patients' Characteristics and Clinical Course of Hypertrophic Cardiomyopathy in a Regional Japanese Cohort - Results From Kochi RYOMA Study

Effect of beta-blockers and exercise restriction on the prevention of sudden cardiac death in pediatric hypertrophic cardiomyopathy

BACKGROUND

Risk assessment tools and effective prevention strategies for sudden cardiac death (SCD) in pediatric patients with hypertrophic cardiomyopathy (HCM) have not been established. This study aimed to evaluate the efficacy of beta-blockers and exercise restriction for SCD prevention in this population.

METHODS

We retrospectively reviewed the medical records of patients aged <18 years who were diagnosed with HCM at our center between January 1996 and December 2021. SCD and aborted SCD were defined as SCD equivalents. We divided patients based on whether they were prescribed beta-blockers or exercise restriction and compared the outcomes among the groups. The primary outcome was the overall survival (OS), and the secondary outcome was the cumulative SCD equivalent rate. Outcomes were analyzed using Kaplan-Meier curves and Cox proportional hazard analysis. We also compared patients according to the occurrence of SCD equivalents to identify SCD risk predictors.

RESULTS

Among the 43 included patients [mean age, 7.7 (1.6-12.1) years; 23 male individuals], SCD equivalents occurred in 13 patients over 11.2 (4.5-15.6) years of follow-up, among whom 12 were resuscitated and 1 died. The OS rate was significantly higher in the beta-blocker and exercise restriction groups than in the non-beta-blocker and non-exercise restriction groups (81.3 % vs. 19.1 %, p < 0.01 and 57.4 % vs. 12.7 %, p < 0.01, respectively). Among the 13 patients with SCD equivalents, 5 had 9 recurrent SCD equivalents. A significant difference was observed between the SCD equivalent and non-SCD equivalent groups in the history of suspected arrhythmogenic syncope (p < 0.01) in the univariable but not in the multivariable analysis.

CONCLUSIONS

Beta-blockers and exercise restriction may decrease the risk of SCD in pediatric patients with HCM and should be considered for SCD prevention in this population, particularly because predicting SCD in these patients remains challenging.

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 systematic review and meta-analysis of sex differences in clinical outcomes of hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is recognized as the most prevalent form of genetic cardiomyopathy, and recent investigations have shed light on the existence of sex disparities in terms of clinical presentation, disease progression, and outcomes.

Objectives

This study aimed to systematically review the literature and perform a meta-analysis to comprehensively compare the clinical outcomes between female and male patients with HCM.

Methods

A thorough search was conducted in databases including PubMed, Embase, Cochrane Library, and Web of Science, encompassing literature from inception until June 2023. The primary endpoints examined were: (1) all-cause mortality; (2) an arrhythmic endpoint comprising sudden cardiac death (SCD), sustained ventricular tachycardia, ventricular fibrillation, or aborted SCD; and (3) a composite endpoint incorporating either (1) or (2), in addition to hospitalization for heart failure or cardiac transplantation. Pooled estimates were derived using a random-effects meta-analysis model.

Results

The analysis encompassed a total of 29 observational studies, involving 44,677 patients diagnosed with HCM, of which 16,807 were female. Baseline characteristics revealed that the female group exhibited an advanced age [55.66 ± 0.04 years vs. 50.38 ± 0.03 years, pooled mean difference (MD) = 0.31, 95% CI: 0.22-0.40, p = 0.000, I2 = 88.89%], a higher proportion of New York Heart Association class III/IV patients [pooled odds ratio (OR) = 1.94, 95% CI: 1.55-2.43, p = 0.000, I2 = 85.92%], and a greater prevalence of left ventricular outflow tract gradient greater than or equal to 30 mmHg (pooled OR = 1.48, 95% CI: 1.27-1.73, p = 0.000, I2 = 68.88%) compared to the male group. The female group were more likely to have a positive genetic test (pooled OR = 1.27, 95% CI: 1.08-1.48, p = 0.000, I2 = 42.74%) and to carry the myosin heavy chain beta 7 mutation (pooled OR = 1.26, 95% CI: 1.04-1.54, p = 0.020, I2 = 0.00%) compared to the male group. Female sex exhibited a significant association with increased risks of all-cause mortality (pooled OR = 1.62, 95% CI: 1.38-1.89, p = 0.000, I2 = 72.78%) and the composite endpoint (pooled OR = 1.47, 95% CI: 1.20-1.79, p = 0.000, I2 = 84.96%), while no substantial difference was observed in the arrhythmic endpoint (pooled OR = 1.08, 95% CI: 0.87-1.34, p = 0.490, I2 = 55.48%).

Conclusions

The present findings suggest that female patients with HCM tend to experience poorer clinical outcomes. It is imperative to critically reevaluate disease definitions and enhance awareness to mitigate delays in the diagnosis and treatment of HCM in women, thereby fostering equitable healthcare practices.

Systematic Review Registration

https://www.crd.york.ac.uk/, PROSPERO (CRD42023431881).

Evolving Contemporary Management of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) with clinical and subclinical episodes occurring in nearly one-half of patients. AF in HCM historically has been characterized as a decisive disease complication associated with substantial risk for thromboembolic stroke and increased morbidity and mortality. However, there have been many advances in treatment strategy resulting in improved outcomes for this patient group. For example, stroke risk in HCM has been greatly reduced by using systemic oral anticoagulation initiated after the first clinical (symptomatic) AF episode, usually with preference given to direct anticoagulants over warfarin. In contrast, stroke risk scoring systems (such as CHA2DS2-VASc score) are not informative in HCM given the substantial potential for stroke events in patients with low scores, and therefore should not be used for anticoagulation decisions in this disease. A novel risk score specifically designed for HCM (HCM-AF score) can reliably identify most patients with HCM at risk for future AF. Although a strategy focused on controlling ventricular rate is effective in asymptomatic (or minimally symptomatic) patients with AF, restoring and maintaining sinus rhythm is required for most patients with marked AF symptom burden and impaired quality of life. Several antiarrhythmic drugs such as sotalol, disopyramide, and amiodarone, can be effective in suppressing AF episodes; albeit safe, long-term efficacy is supported by only limited data. Catheter AF ablation has emerged as an important treatment option for some patients, although freedom from AF after a single ablation is relatively low (35% at 3 years), multiple ablations and the concomitant use of antiarrhythmic drugs can control AF with more than two-thirds of patients maintaining sinus rhythm at 5 years. Surgical AF ablation with biatrial Cox-Maze IV performed as an adjunctive procedure during myectomy can reduce symptomatic AF episodes (70% of patients free from AF at 5 years). For the vast majority of patients who have HCM with AF, the implementation of contemporary therapies has allowed for improved quality of life and low HCM-related mortality.

Predictive Factors for Decreasing Left Ventricular Ejection Fraction and Progression to the Dilated Phase of Hypertrophic Cardiomyopathy

Patients with hypertrophic cardiomyopathy (HCM) may progress to the dilated phase (DHCM). This study aimed to identify the predictive factors for DHCM progression, including left ventricular (LV) ejection fraction (LVEF < 50%) or decreased LV contraction (LVEF < 60%). The study included 291 patients enrolled in our hospital's HCM registry who were grouped based on their poststudy LVEF (LVEF of ≥60%, 50-59%, and <50%). Predictive factors of an LVEF of <50% or <60% were determined. Further, the effects of percutaneous transluminal septal myocardial ablation (PTSMA) on long-term systolic LV function and DHCM development were investigated. LVEF was ≥60%, 50-59%, and <50% in 239, 33, and 19 patients, respectively, during the follow-up period (mean: 64.9 months). Multivariate analyses indicated baseline atrial fibrillation (AF), nonsustained ventricular tachycardia (NSVT), and left ventricular diameter at end-systole (LVDs) as significant predictors of DHCM. Using a scoring method based on AF, NSVT, and LVDs, patients with 2 and 3 points had a significantly higher risk of developing DHCM. PTSMA in 78 HCM patients demonstrated no significant effect on long-term LVEF changes or DHCM development. We concluded that AF, NSVT, and LVDs are significant predictors of DHCM development. However, a validation study with a larger population is required.

Clinical Features of Heart Failure in Patients With Hypertrophic Cardiomyopathy in a Regional Japanese Cohort - Results From the Kochi RYOMA Study

BACKGROUND

The clinical features of heart failure (HF) in patients with hypertrophic cardiomyopathy (HCM) in Japan have not been fully elucidated.

METHODS AND RESULTS

In 293 patients with HCM (median age at registration, 65 (57-72) years) in a prospective cardiomyopathy registration network in Kochi Prefecture (Kochi RYOMA study), HF events (HF death or hospitalization for HF) occurred in 35 patients (11.9%) (median age, 76 (69-80) years), including 11 HF deaths during a median follow-up of 6.1 years. The 5-year HF events rate was 9.6%. Atrial fibrillation, low percentage of fractional shortening, and high B-type natriuretic peptide level at registration were predictors of HF events. The combination of these 3 factors had a relatively high positive predictive value (55%) for HF events and none of them had a high negative predictive value (99%). There were 4 types of HF profile: left ventricular (LV) systolic dysfunction (40%), severe LV diastolic dysfunction (34%), LV outflow tract obstruction (LVOTO) (20%), and primary mitral regurgitation (MR) (6%). HF deaths occurred in patients with LV systolic dysfunction or LV diastolic dysfunction, but none of patients with LVOTO or primary MR due to additional invasive therapies.

CONCLUSIONS

In a Japanese HCM cohort, HF was an important complication, requiring careful follow-up and appropriate treatment.

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.

Major Clinical Issues in Hypertrophic Cardiomyopathy

By actively implementing contemporary management strategies in hypertrophic cardiomyopathy, morbidity and mortality can be substantially reduced. In this review, we discuss the pathophysiology and management of the major clinical issues in hypertrophic cardiomyopathy, including sudden cardiac death, atrial fibrillation and thromboembolism, dynamic left ventricular outflow tract obstruction, and heart failure progression. Although echocardiography and cardiac magnetic resonance imaging currently play an essential and complementary role in the management of hypertrophic cardiomyopathy, further studies are needed to establish how developing techniques such as myocardial deformation and late gadolinium enhancement can provide better risk stratification and guide treatment.

Hypertrophic cardiomyopathy (HCM) is one of the most common inheritable cardiomyopathies. Contemporary management strategies, including the advent of implantable cardioverter-defibrillators and effective anticoagulation, have substantially improved the clinical course of HCM patients; however, the disease burden of HCM is still high in Korea. Sudden cardiac death (SCD), atrial fibrillation and thromboembolic risk, dynamic left ventricular outflow tract (LVOT) obstruction, and heart failure (HF) progression remain important issues in HCM. SCD in HCM can be effectively prevented with implantable cardioverter-defibrillators. However, appropriate patient selection is important for primary prevention, and the 5-year SCD risk score and the presence of major SCD risk factors should be considered. Anticoagulation should be initiated in all HCM patients with atrial fibrillation regardless of the CHA₂DS₂-VASc score, and non-vitamin K antagonist oral anticoagulants are the first option. Symptomatic dynamic LVOT obstruction is first treated medically with negative inotropes, and if symptoms persist, septal reduction therapy is considered. The recently approved myosin inhibitor mavacamten is promising. HF in HCM is usually related to diastolic dysfunction, while about 5% of HCM patients show reduced left ventricular ejection fraction <50%, also referred to as “end-stage” HCM. Myocardial fibrosis plays an important role in the progression to advanced HF in patients with HCM. Patients who do not respond to guideline-directed medical therapy can be considered for heart transplantation. The development of imaging techniques, such as myocardial deformation on echocardiography and late gadolinium enhancement on cardiac magnetic resonance, can provide better risk evaluation and decision-making for management strategies in HCM.

Clinical significance of new-onset atrial fibrillation in patients with hypertrophic cardiomyopathy

Aims

There is limited information about the clinical significance of atrial fibrillation (AF), particularly new‐onset AF, in patients with hypertrophic cardiomyopathy (HCM) in a community‐based patient cohort. This study was carried out to clarify the prevalence and prognostic impact of AF in Japanese HCM patients.

Methods and results

In 2004, we established a cardiomyopathy registration network in Kochi Prefecture as a prospective study, and finally, 293 patients with HCM were followed. In the patients' cohort, we recently reported the clinical outcomes including mortality and HCM‐related morbid events. HCM‐related adverse cardiovascular events were defined in the following: (i) sudden cardiac death (SCD)‐relevant events including SCD, spontaneous sustained ventricular tachycardia, and appropriate implantable cardioverter defibrillator discharge; (ii) heart failure (HF) events with the composite of HF death and hospitalization for HF; and (iii) embolic events included embolic stroke‐related death and admission for embolic events. In the present study, we focused on AF and conducted a detailed investigation. At registration, the mean age of the patients was 63 ± 14 years, and 86 patients (29%) had documented AF including paroxysmal AF. Patients with AF at registration were characterized by worse clinical profiles including more advanced age, more symptomatic, more advanced left ventricular, and left atrial remodelling at registration. During a mean follow‐up period of 6.1 ± 3.2 years, a total of 77 HCM‐related adverse events occurred, and the presence of AF at registration was associated with an increased risk of HCM‐related adverse events, particularly heart failure events. During the follow‐up period, an additional 31 patients (11%) had documentation of AF for the first time, defined as new‐onset AF, with an annual incidence of approximately 1.8%, and finally, a total of 117 patients (40%) showed AF. The presence of palpitation and enlarged left atrial diameter, particularly left atrial diameter ≥50 mm, at registration were significant predictors of new‐onset AF. Importantly, the incidence of overall HCM‐related adverse events was further higher in patients with new‐onset AF observed from AF onset than in patients with AF at registration.

Conclusions

In our HCM registry in an aged Japanese community, a significant proportion developed AF. The presence of AF, particularly new‐onset AF, was associated with increased incidence of HCM‐related events. AF may not be just a marker of disease stage but an important trigger of adverse events.

Importance of Paroxysmal Atrial Fibrillation and Sex Differences in the Prevention of Embolic Stroke in Hypertrophic Cardiomyopathy

Background: Although atrial fibrillation (AF) is a well-known risk factor for embolic stroke in hypertrophic cardiomyopathy (HCM), there is a paucity of information derived from HCM patients who have experienced embolic stroke.

Methods and Results: From 141 consecutive HCM patients who had been hospitalized between 2000 and 2018, the clinical characteristics and management of 86 patients with AF were analyzed retrospectively. The incidence of embolic stroke was 36% (n=31 patients). The median (interquartile range) age of embolic stroke was younger in male than female HCM patients (71 [64–80] vs. 83 [77–87] years, respectively; P=0.009). The prevalence of paroxysmal AF (74%) was significantly higher than that of chronic AF (26%) in 31 patients with embolic stroke (P=0.007). The CHADS₂ score in patients with embolic stroke was not particularly useful in predicting the occurrence of embolic stroke.

Conclusions: One-third of HCM patients with AF developed embolic stroke, and male HCM patients were younger at the time of the embolic stroke than female HCM patients. The prevalence of paroxysmal AF was significantly higher than that of chronic AF in patients with AF and embolic stroke. Early introduction of anticoagulation therapy is recommended at the first documentation of paroxysmal AF.

Clinical Characteristics and Contemporary Management of Patients With Cardiomyopathies in Japan - Report From a National Registry of Clinical Personal Records

Background: The clinical features of patients with cardiomyopathy, including dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), or restrictive cardiomyopathy (RCM), have not been recently elucidated in Japan.

Methods and Results: We collected individual patient data regarding demographics, echocardiogram, and treatment in DCM from 2003 to 2014 and in HCM and RCM from 2009 to 2014 from the national registry of clinical personal records organized by the Japanese Ministry of Health, Labour and Welfare. In all, 44,136 patients were included in this registry: 40,537 with DCM, 3,553 with HCM, and 46 with RCM. The median age at diagnosis was older for DCM and HCM than RCM (54 and 55 vs. 42 years, respectively). Male patients accounted for 74.6%, 58.7%, and 60.9% of the DCM, HCM, and RCM groups, respectively. NYHA functional Class III–IV was found in 26.9%, 11.3%, and 58.1% of patients in the DCM, HCM, and RCM groups, respectively. In the DCM group, the rates of β-blocker and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker prescription were 69% and 76%, respectively. In regional subgroup analysis, the median age at diagnosis of DCM and HCM was younger in the Kanto region. A family history of HCM was less frequent in the Hokkaido/Tohoku region.

Conclusions: The national registry of clinical personal records of cardiomyopathy could provide important information regarding the demographics, clinical characteristics, and management of cardiomyopathy throughout Japan.

Myocardial contraction fraction predicts mortality for patients with hypertrophic cardiomyopathy

The myocardial contraction fraction (MCF: stroke volume to myocardial volume) is a novel volumetric measure of left ventricular myocardial shortening. The purpose of the present study was to assess whether MCF could predict adverse outcomes for HCM patients. A retrospective cohort study of 438 HCM patients was conducted. The primary and secondary endpoints were all-cause mortality and HCM-related mortality. The association between MCF and endpoints was analysed. During a follow-up period of 1738.2 person-year, 76 patients (17.2%) reached primary endpoint and 50 patients (65.8%) reached secondary endpoint. Both all-cause mortality rate and HCM-related mortality rate decreased across MCF tertiles (24.7% vs. 17.9% vs. 9.5%, P trend = 0.003 for all-cause mortality; 16.4% vs. 9.7% vs. 6.1%, P trend = 0.021 for HCM-related mortality). Patients in the third tertile had a significantly lower risk of developing adverse outcomes than patients in the first tertile: all-cause mortality (adjusted HR: 0.26, 95% CI: 0.12–0.56, P = 0.001), HCM-related mortality (adjusted HR: 0.17, 95% CI: 0.07–0.42, P < 0.001). At 1-, 3-, and 5-year of follow-up, areas under curve were 0.699, 0.643, 0.618 for all-cause mortality and 0.749, 0.661, 0.613 for HCM-related mortality (all P value < 0.001), respectively. In HCM patients, MCF could independently predict all-cause mortality and HCM-related mortality, which should be considered for overall risk assessment in clinical practice.

Elevation of high-sensitivity cardiac troponin T and left ventricular remodelling in hypertrophic cardiomyopathy

Aims

Hypertrophic cardiomyopathy (HCM) is generally associated with mild disability and normal life expectancy. On the other hand, once the end‐stage phase of HCM characterized by left ventricular (LV) ejection fraction < 50% is established, patients with this subtype have a poor prognosis. This study clarifies the clinical parameters associated with progression to end‐stage HCM.

Methods and results

We retrospectively studied 157 HCM patients (age 59.9 ± 14.2 years, 104 men) with preserved LV systolic function in whom subsequent echocardiographic data were obtained for a period of >1 year. HCM progressed to end‐stage HCM in 13 patients (8.3%) of the 157 patients during a mean follow‐up period of 6.3 ± 2.8 years. Compared with patients who did not reach end‐stage HCM at the last evaluation, patients with progression to the end‐stage phase had lower ejection fraction, larger LV size, more enlarged left atrial diameter, longer follow‐up period, and higher frequency of an elevated concentration of high‐sensitivity cardiac troponin T (hs‐cTnT; >0.014 ng/mL) at registration. Multivariate analysis revealed that elevated hs‐cTnT was a significant predictor independent of lower LV ejection fraction for progression to end‐stage HCM. Furthermore, in patients with elevated hs‐cTnT levels, LV ejection fraction became significantly lower, LV end‐diastolic diameter increased, and LV wall thickness decreased during the follow‐up period, whereas those parameters did not change in the normal hs‐cTnT group.

Conclusions

In patients with HCM, an elevated hs‐cTnT was associated with progression of LV remodelling, and this biomarker can be useful for predicting progression to the end‐stage phase.

Lifelong Clinical Impact of the Presence of Sarcomere Gene Mutation in Japanese Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is mainly caused by mutations in sarcomere genes. Regarding the clinical implications of genetic information, little is known about the lifelong clinical effect of sarcomere mutations in Japanese HCM patients.

METHODS AND RESULTS

We studied 211 consecutive Japanese patients with HCM who had agreed to genetic testing between 2003 and 2013. Genetic analyses were performed by direct DNA sequencing in the 6 common sarcomere genes (MYH7,MYBPC3,TNNT2,TNNI3,TPM1,ACTC). Through variant filtering, 21 mutations were identified in 67 patients. After excluding 8 patients whose variants were determined as having uncertain significance, finally 203 patients (130 men, age at study entry: 61.8±14.1 years) were investigated for clinical presentation and course. At the time of study entry, patients with mutations were younger, had more frequent non-sustained ventricular tachycardia, had greater interventricular wall thickness, were more frequently in the dilated phase and less frequently had apical HCM. Through their lifetimes, a total of 98 HCM-related morbid events occurred in 72 patients. Survival analysis revealed that patients with sarcomere gene mutations experienced those morbid events significantly more frequently, and this tendency was more prominent for lethal arrhythmic events.

CONCLUSIONS

In our HCM cohort, patients with sarcomere gene mutations had poorer lifelong outcome. Genetic information is considered important for better management of HCM.

Sudden Cardiac Death-Relevant Events of Hypertrophic Cardiomyopathy in a Regional Japanese Cohort ― Results From the Kochi RYOMA Study ―

Background: Sudden cardiac death (SCD) is a most devastating complication of hypertrophic cardiomyopathy (HCM). The aim of this study was to clarify the clinical features of HCM in patients who experienced SCD-relevant events in an aged Japanese community.

Methods and Results: In 2004, we established a cardiomyopathy registration network in Kochi Prefecture, and herein report on 293 patients with HCM who are followed as part of the registry. The mean (±SD) age at registration and diagnosis was 63±14 and 56±16 years, respectively. SCD-relevant events occurred in 19 patients during a mean follow-up period of 6.1±3.2 years (incidence rate 1.0%/year): sudden death in 9 patients, successful recovery from cardiopulmonary arrest in 4 patients, and appropriate implantable cardioverter–defibrillator discharge in 6 patients. At registration, 13 patients were in the dilated phase of HCM (D-HCM). During the follow-up period, HCM developed to D-HCM in 21 patients; thus, 34 patients in total had D-HCM. Multivariate analysis revealed that D-HCM at registration or during follow-up and detection of non-sustained ventricular tachycardia (NSVT) during follow-up were significant predictors of SCD-relevant events.

Conclusions: In this HCM population in an aged Japanese community, the annual rate of SCD-relevant events was 1.0%. HCM developed to D-HCM in a considerable number of patients, and D-HCM and NSVT were shown to be independently associated with an increased risk of SCD-relevant events.

Hypertrophic Cardiomyopathy - A Heterogeneous and Lifelong Disease in the Real World

Hypertrophic cardiomyopathy (HCM) is the most frequent hereditary cardiomyopathy, showing an autosomal-dominant f inheritance. A great deal of attention has been paid to genetics, left ventricular tract obstruction and the prediction and prevention of sudden cardiac death in HCM. Needless to say, these are very important, but we should recognize the heterogeneity in etiology, morphology, clinical course and management of this unique cardiomyopathy. Another important perspective is that HCM causes left ventricular remodeling over time and is a disease that requires lifelong management in the real world.

Clinical Profile of Thromboembolic Events in Patients With Hypertrophic Cardiomyopathy in a Regional Japanese Cohort - Results From Kochi RYOMA Study

BACKGROUND

There is limited information about the clinical profiles of patients with hypertrophic cardiomyopathy (HCM) and thromboembolic events in a community-based Japanese patient cohort.Methods and Results:In 2004, we established a cardiomyopathy registration network in Kochi Prefecture that comprised 9 hospitals, and finally 293 patients with HCM were followed. The mean age at registration was 63±14 years, and 197 patients (67%) were men. At registration, 86 patients (29%) had documented atrial fibrillation (AF). During a mean follow-up period of 6.1±3.2 years, thromboembolic events, including 3 embolic stroke deaths, occurred in 23 patients. The 5-year embolic event rate was 5.5%. During the follow-up period, an additional 31 patients (11%) had documentation of AF and finally a total of 117 patients (40%) developed AF. The 5-year embolic event rate in those 117 patients with AF was 12.3%. Of the 23 patients with embolic events, 12 had AF prior to the embolic complications and another 6 had documented AF after thromboembolism. AF was not detected in the remaining 5 patients. The CHADS₂score did not correlate with the embolic outcome in HCM patients.

CONCLUSIONS

In this community-based registry, thromboembolic events were not rare in patients with HCM. All patients with HCM in whom AF develops should be given anticoagulation therapy regardless of their CHADS₂score.

Modes of death and clinical outcomes in adult patients with hypertrophic cardiomyopathy in Thailand

Background

There are limited data about modes of death and major adverse cardiovascular events (MACEs) in patients with hypertrophic cardiomyopathy (HCM) in South East Asian population. The aim of the study was to examine modes of death and clinical outcomes in Thai patients with HCM.

Methods

Between January 1, 2009 and December 31, 2013, 166 consecutive patients with HCM diagnosed in our institution were evaluated. Five patients were excluded because of non-Thai ethnic groups (n = 3) and diagnosis of myocardial infarction at initial presentation documented by coronary angiography (n = 2). The final study population consisted of 161 patients with HCM. HCM-related deaths included: (1) sudden cardiac death (SCD) – death due to sudden cardiac arrest or unexpected sudden death; (2) heart failure – death due to refractory heart failure; or (3) stroke - death due to embolic stroke associated with atrial fibrillation. MACEs included: (1) SCD, sudden unexpected aborted cardiac arrest, fatal, or nonfatal ventricular arrhythmia (ventricular fibrillation or sustained ventricular tachycardia); (2) heart failure (fatal or non-fatal), or heart transplantation; or (3) stroke - fatal or non-fatal embolic stroke associated with atrial fibrillation.

Results

One hundred and sixty-one Thai patients with HCM (age 66 ± 16 years, 58% female) were enrolled. Forty-two patients (26%) died over a median follow-up period of 6.8 years including 25 patients (16%) with HCM-related deaths (2%/year). The HCM-related deaths included: heart failure (52% of HCM-related deaths; n = 13), SCD (44% of HCM-related deaths; n = 11), and stroke (4% of HCM-related deaths, n = 1). The SCDs occurred in 6.8% of patients (1%/year). Eighty-four major MACEs occurred in 65 patients (41, 5%/year). The MACEs included: 40 heart failures in which 2 patients underwent heart transplants; 22 SCDs and nonfatal ventricular arrhythmias; and 22 fatal or nonfatal strokes.

Conclusions

The most common mode of death in adult patients with HCM in Thailand was heart failure followed by SCD. About one-third of the patients experiencing heart failure died during the 6.8 years of follow-up. SCDs occurred in 7% of patients (1%/year), predominantly in the fourth decade or later.

Validation of the 2014 European Society of Cardiology Sudden Cardiac Death Risk Prediction Model Among Various Phenotypes in Japanese Patients With Hypertrophic Cardiomyopathy

Risk stratification for sudden cardiac death (SCD) is essential in the management of hypertrophic cardiomyopathy (HC). The 2014 European Society of Cardiology SCD risk prediction model (Risk-SCD) is a novel risk scoring system; however, whether it can be applied to Japanese HC and its usefulness among various HC phenotypes remain unclear. The aim of this study was to validate the Risk-SCD model in Japanese HC, and to evaluate its usefulness among various HC phenotypes. We studied 370 consecutive Japanese HC patients evaluated for primary SCD prevention at our tertiary referral center. The Risk-SCD model was validated in 289 HC patients with ejection fraction (EF) ≥50% (including left ventricular outflow tract obstruction [LVOTO], mid ventricular obstruction [MVO], apical hypertrophy, and nonobstructive phenotypes), and 81 end-stage HC patients (EF <50%). The end point of the study was SCD or an equivalent event (appropriate implantable cardioverter defibrillator therapy or successful resuscitation after cardiac arrest). Thirty-one SCD events were observed during a median follow-up of 5.2 (interquartile range 3.5 to 6.9) years. The Risk-SCD model showed improved risk prediction in HC with EF ≥50% compared with the previous 2011 American College of Cardiology Foundation/American Heart Association and 2003 American College of Cardiology/European Society of Cardiology guideline approaches (number needed to treat = 3.8 at Risk-SCD >6%) regardless of phenotypes; LVOTO, MVO, apical, and nonobstructive, but misclassified SCD risk in end-stage HC. In the current external validation of the Risk-SCD model in Japanese HC, the model improved SCD prediction compared with previous approaches, and was also shown to be useful in LVOTO, MVO, apical, and nonobstructive phenotypes.