Predictors of atrial fibrillation in hypertrophic cardiomyopathy

Implication of Apnea-Hypopnea Index, a Measure of Obstructive Sleep Apnea Severity, for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Background

Obstructive sleep apnea (OSA) is common and independently associated with atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). This study aimed to investigate the relationship between apnea‐hypopnea index (AHI), a measure of OSA severity, and prevalence of AF in a large series of patients with HCM.

Methods and Results

A total of 555 patients with HCM who underwent sleep evaluations were retrospectively included. Data from polysomnography studies, echocardiography, and baseline clinical characteristics were collected. OSA was present in 327 patients (58.9%). Patients with OSA or higher AHI quartiles were older, more often male, had a higher body mass index, and more clinical comorbidities. The prevalence of AF increased in patients with OSA (23.9% versus 13.6%, P=0.003) or across AHI quartiles (9.4%, 17.3%, 26.6%, and 25.2%, respectively; P for trend <0.001). After adjustment for age, sex, body mass index, New York Heart Association class, left atrial diameter, hypertension, oxygen desaturation index, and obstructive HCM, highest AHI quartile (odds ratio, 4.42; 95% CI, 1.35–14.52 [P=0.014]) or moderate to severe OSA (odds ratio, 3.03; 95% CI, 1.28–7.20 [P=0.012]) but not presence of OSA (odds ratio, 1.58; 95% CI, 0.84–2.97 [P=0.153]) were significantly associated with AF. Higher AHI levels were also factors associated with persistent or permanent AF (highest AHI quartile with odds ratio, 10.96; 95% CI, 1.07–111.85).

Conclusions

Severity of AHI level is independently associated with AF in patients with HCM. Clinical trials are required to determine the benefits of OSA treatment on AF in patients with HCM.

Atrial Fibrillation in Hypertrophic Cardiomyopathy: Evidence-based Review About Mechanism, Complications and Management

Hypertrophic cardiomyopathy (HCM) is 1 of the most frequent genetic cardiovascular diseases affecting 1 out of every 500 individuals in general population. Atrial Fibrillation incidences were 3.8% per 100 patients per year and overall prevalence among HCM patients are 27.09%. Higher risk of death noted in HCM patients with atrial fibrillation. Stroke and other thrombo embolic risks are increased in such patients. Medical management using mainly betablockers or amiodarone produced variable results and high rate of recurrence. Catheter ablation reduced symptom burden and complications despite moderate recurrence. Patients with multiple repeated procedures found to have better success rate and outcomes. The complications are not high leading to increased feasibility of the procedure. More research using latest techniques in catheter ablation need to be studied.

Incident Atrial Fibrillation Is Associated With MYH7 Sarcomeric Gene Variation in Hypertrophic Cardiomyopathy

Background Although atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM) patients, the relationship between genetic variation and AF has been poorly defined. Characterizing genetic subtypes of HCM and their associations with AF may help to improve personalized medical care. We aimed to investigate the link between sarcomeric gene variation and incident AF in HCM patients. Methods and Results Patients from the multinational Sarcomeric Human Cardiomyopathy Registry were followed for incident AF. Those with likely pathogenic or pathogenic variants in sarcomeric genes were included. The AF incidence was ascertained by review of medical records and electrocardiograms at each investigative site. One thousand forty adult HCM patients, without baseline AF and with likely pathogenic or pathogenic variation in either MYH7 (n=296), MYBPC3 (n=659), or thin filament genes (n=85), were included. Compared with patients with variation in other sarcomeric genes, those with MYH7 variants were younger on first clinical encounter at the Sarcomeric Human Cardiomyopathy Registry site and more likely to be probands than the MYBPC3 variants. During an average follow-up of 7.2 years, 198 incident AF events occurred. Patients with likely pathogenic or pathogenic mutations in MYH7 had the highest incidence of AF after adjusting for age, sex, proband status, left atrial size, maximal wall thickness, and peak pressure gradient (hazard ratio, 1.7; 95% CI, 1.1-2.6; P=0.009). Conclusions During a mean follow-up of 7.2 years, new-onset AF developed in 19% of HCM patients with sarcomeric mutations. Compared with other sarcomeric genes, patients with likely pathogenic or pathogenic variation in MYH7 had a higher rate of incident AF independent of clinical and echocardiographic factors.

Risk factors for atrial fibrillation in hypertrophic cardiomyopathy

Atrial fibrillation is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), occurring in approximately 25% of patients, which is four to six times more common than in similarly aged patients of the general population. Atrial fibrillation is poorly tolerated by HCM patients, largely due to their dependence on atrial systole for left ventricular filling. HCM patients who develop atrial fibrillation have an increased rate of heart failure related mortality and disabling or fatal thromboembolic events, as well as functional deterioration due to progressive heart failure when left untreated. Atrial fibrillation is both common in HCM and may lead to significant morbidity and mortality. Accurate risk stratification for atrial fibrillation in this population is crucial as contemporary treatments are highly successful. In this paper, we review the current understanding of known risk factors for atrial fibrillation, including different imaging-based parameters that assess left atrial structural and functional remodeling, electrocardiographic changes that reflect left atrial electrical remodeling, and a focus on comorbid obstructive sleep apnea, and in addition we review variables that have been reported to be predictive of atrial fibrillation. Last, we summarize the accumulating evidence for HCM patients having an intrinsic atrial myopathy.

Left Atrial Volume during Stress Is Associated with Increased Risk of Arrhythmias in Patients with Hypertrophic Cardiomyopathy

Introduction:

In patients affected by hypertrophic cardiomyopathy (HCM), left atrial volume index (LAVi) is associated with an increased risk of tachyarrhythmias and major clinical events. To date, the clinical meaning of LAVi measured during exercise (stress LAVi [sLAVi]) has not yet been investigated in HCM. This study sought to evaluate the correlation between LAVi/sLAVi and clinical outcome (risk of arrhythmias and heart failure [HF]) in patients with HCM.

Methods and Results:

We enrolled a total of 51 consecutive patients with HCM (39 men; mean age: 39.41 ± 17.9 years) who underwent standard and stress echocardiography, following a common protocol. During follow-up (median follow-up was 1.82 years), the following composite endpoints were collected: ARRHYT endpoint (atrial fibrillation, paroxysmal supraventricular tachycardia, nonsustained ventricular tachycardia (VT), sustained VT, ventricular fibrillation, syncope of likely cardiogenic nature, and sudden cardiac death) and HF endpoint (worsening of functional class and left ventricular ejection fraction, hospitalization, and death for end-stage HF). Eight patients were lost at follow-up. ARRHYT endpoint occurred in 13 (30.2%) patients (8, 18.6%, supraventricular and 10, 23.2%, ventricular arrhythmias), whereas HF endpoint occurred in 5 (11.6%) patients. sLAVi (mean value of 31.16 ± 10.15 mL/m²) performed better than rLAVi as a predictor of ARRHYT endpoint (Akaike Information Criterion: 48.37 vs. 50.37, if dichotomized according to the median values). A sLAVi value of 30 mL/m² showed a predictive accuracy of 72.1% (C-statistics of 0.7346), with a high negative predictive value (87.5%).

Conclusion:

These findings encourage future studies on sLAVi, as a potential predictor of arrhythmias and adverse outcome in patients with HCM.

Effect of hypertrophic cardiomyopathy on the prediction of thromboembolism in patients with nonvalvular atrial fibrillation

BACKGROUND

Anticoagulation is recommended for hypertrophic cardiomyopathy (HCM) with nonvalvular atrial fibrillation (NVAF) according to European and American guidelines. However, it is unclear whether HCM is a risk factor for thromboembolism in NVAF in Japan, and the management for NVAF with HCM is not established.

OBJECTIVE

We studied the impact of concomitant HCM on predicting thromboembolism in NVAF.

METHODS

We retrospectively studied consecutive 2374 Japanese patients with NVAF (1682 men, 70.9%; mean age 71±10 years). Clinical factors were evaluated using the Cox proportional hazards model. We also investigated whether adding HCM to CHADS₂ or CHA₂DS₂-VASc score improved the prediction of thromboembolism.

RESULTS

Thromboembolism was observed in 122 patients (5.1%) during the median follow-up of 2.4 years (interquartile range 2.0-3.2 years). The Cox proportional hazards model showed that HCM was significantly associated with thromboembolism after adjustment for CHADS₂ or CHA₂DS₂-VASc score (hazard ratio 3.41; 95% confidence interval [CI] 1.98-5.73; P<.0001 and hazard ratio 3.38; 95% CI 1.97-5.64; P<.0001, respectively). NVAF with HCM had significantly higher thromboembolism rates, even in those with a CHADS₂ or CHA₂DS₂-VASc score of 1 or 0-1, respectively. Based on the comparison of C-statistics, the addition of HCM to CHADS₂ or CHA₂DS₂-VASc score significantly improved the prediction of thromboembolism (C-statistics 0.75 vs 0.71; P=.003 and C-statistics 0.77 vs 0.71; P=.0001, respectively).

CONCLUSION

HCM is an independent risk factor for thromboembolism in patients with NVAF. A markedly high incidence of thromboembolism is observed in NVAF patients with HCM with CHA₂DS₂-VASc score of both ≥2 and 0-1, and anticoagulation therapy is recommended for them.

Genotype and Lifetime Burden of Disease in Hypertrophic Cardiomyopathy: Insights from the Sarcomeric Human Cardiomyopathy Registry (SHaRe)

Background

A better understanding of the factors that contribute to heterogeneous outcomes and lifetime disease burden in hypertrophic cardiomyopathy (HCM) is critically needed to improve patient management and outcomes. The Sarcomeric Human Cardiomyopathy Registry (SHaRe) was established to provide the scale of data required to address these issues, aggregating longitudinal datasets curated by eight international HCM specialty centers.

Methods

Data on 4591 HCM patients (2763 genotyped), followed for a mean of 5.4±6.9 years (24,791 patient-years; median [interquartile range] 2.9 [0.3-7.9] years) were analyzed regarding cardiac arrest, cardiac transplantation, appropriate implantable cardioverter-defibrillator (ICD) therapy, all-cause death, atrial fibrillation, stroke, New York Heart Association Functional Class III/IV symptoms (all comprising the overall composite endpoint), and left ventricular ejection fraction (LVEF)<35%. Outcomes were analyzed individually and as composite endpoints.

Results

Median age of diagnosis was 45.8 [30.9-58.1] years and 37% of patients were female. Age of diagnosis and sarcomere mutation status were predictive of outcomes. Patients <40 years old at diagnosis had a 77% [95% confidence interval: 72%, 80%] cumulative incidence of the overall composite outcome by age 60, compared to 32% [29%, 36%] by age 70 for patients diagnosed >60 years. Young HCM patients (20-29 years) had 4-fold higher mortality than the general United States population at a similar age. Patients with pathogenic/likely pathogenic sarcomere mutations had two-fold greater risk for adverse outcomes compared to patients without mutations; sarcomere variants of uncertain significance were associated with intermediate risk. Heart failure and atrial fibrillation were the most prevalent adverse events, although typically not emerging for several years after diagnosis. Ventricular arrhythmias occurred in 32% [23%, 40%] of patients <40 years at diagnosis, but in 1% [1%, 2%] >60 years.

Conclusions

The cumulative burden of HCM is substantial and dominated by heart failure and atrial fibrillation occurring many years following diagnosis. Young age of diagnosis and the presence of a sarcomere mutation are powerful predictors of adverse outcomes. These findings highlight the need for close surveillance throughout life, and the need to develop disease-modifying therapies.

Temporal trends of the prevalence and incidence of atrial fibrillation and stroke among Asian patients with hypertrophic cardiomyopathy: A nationwide population-based study

BACKGROUND

Atrial fibrillation (AF) and stroke are common in hypertrophic cardiomyopathy (HCM). We aimed to determine the prevalence and incidence of AF and stroke in patients with HCM during a 10-year period.

METHODS

Using the Korean National Health Insurance Services database, we identified patients diagnosed with HCM from the entire Korean population between 2005 and 2015. The annual prevalence and incidence of AF and stroke in HCM patients were estimated.

RESULTS

The prevalence of AF in HCM patients has gradually increased to 1.6-fold from 13.4% in 2005 to 20.9% in 2015. The incidence of AF ranged from 4.1 to 5.5%, a similar trend was observed for each year in HCM patients. The prevalence of stroke in HCM patients was approximately 10%, while that in HCM patients with AF was about 20%. During 8741 person-years, AF-related stroke occurred in 257 subjects among 2309 HCM patients with new-onset AF. The overall incidence rate of AF-associated stroke was 2.94 per 100 person-years. In subgroup analysis, the incidence rate of AF-associated stroke was 1.49 per 100 person-years in the under 45 year-old group and 1.48 per 100 person-years in the group with CHA₂DS₂-VASc score of 0 or 1 point in HCM patients.

CONCLUSIONS

The prevalence of AF in HCM patients gradually increased over 10 years. The annual risk of AF-associated stroke in HCM was over 1% even in younger patients and those with CHA₂DS₂-VASc score of 0 or 1 point, which provide evidence to support the prevention of stroke in HCM patients with AF.

Clinical Outcomes in Patients With Nonobstructive, Labile, and Obstructive Hypertrophic Cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is a common inherited cardiac disease characterized by varying degrees of left ventricular outflow tract obstruction. In a large cohort, we compare the outcomes among 3 different hemodynamic groups.

Methods and Results

We prospectively enrolled patients fulfilling standard diagnostic criteria for HCM from January 2005 to June 2015. Detailed phenotypic characterization, including peak left ventricular outflow tract pressure gradients at rest and after provocation, was measured by echocardiography. The primary outcome was a composite cardiovascular end point, which included new‐onset atrial fibrillation, new sustained ventricular tachycardia/ventricular fibrillation, new or worsening heart failure, and death. The mean follow‐up was 3.4±2.8 years. Among the 705 patients with HCM (mean age, 52±15 years; 62% men), 230 with obstructive HCM were older and had a higher body mass index and New York Heart Association class. The 214 patients with nonobstructive HCM were more likely to have a history of sustained ventricular tachycardia/ventricular fibrillation and implantable cardioverter defibrillator implantation. During follow‐up, 121 patients experienced a composite cardiovascular end point. Atrial fibrillation occurred most frequently in the obstructive group. Patients with nonobstructive HCM had more frequent sustained ventricular tachycardia/ventricular fibrillation events. In multivariate analysis, obstructive (hazard ratio, 2.80; 95% confidence interval, 1.64–4.80) and nonobstructive (hazard ratio, 1.94; 95% confidence interval, 1.09–3.45) HCM were associated with more adverse events compared with labile HCM.

Conclusions

Nonobstructive HCM carries notable morbidity, including a higher arrhythmic risk than the other HCM groups. Patients with labile HCM have a relatively benign clinical course. Our data suggest detailed sudden cardiac death risk stratification in nonobstructive HCM and monitoring with less aggressive management in labile HCM.

Clinical Profile and Consequences of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Background:

Atrial fibrillation (AF), the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), is capable of producing symptoms that impact quality of life and is associated with risk for embolic stroke. However, the influence of AF on clinical course and outcome in HCM remains incompletely resolved.

Methods:

Records of 1558 consecutive patients followed at the Tufts Medical Center Hypertrophic Cardiomyopathy Institute for 4.8±3.4 years (from 2004 to 2014) were accessed.

Results:

Of the 1558 patients with HCM, 304 (20%) had episodes of AF, of which 226 (74%) were confined to symptomatic paroxysmal AF (average, 5±5; range, 1 to >20), whereas 78 (26%) developed permanent AF, preceded by 7±6 paroxysmal AF episodes. At last evaluation, 277 patients (91%) are alive at 62±13 years of age, including 89% in New York Heart Association class I or II. No difference was found in outcome measures for patients with AF and age- and sex-matched patients with HCM without AF. Four percent of patients with AF died of HCM-related causes (n=11), with annual mortality 0.7%; mortality directly attributable to AF (thromboembolism without prophylactic anticoagulation) was 0.1% per year (n=2 patients). Patients were treated with antiarrhythmic drugs (most commonly amiodarone [n=103] or sotalol [n=78]) and AF catheter ablation (n=49) or the Maze procedure at surgical myectomy (n=72). Freedom from AF recurrence at 1 year was 44% for ablation patients and 75% with the Maze procedure ( P <0.001). Embolic events were less common with anticoagulation prophylaxis (4/233, 2%) than without (9/66, 14%) ( P <0.001).

Conclusions:

Transient symptomatic episodes of AF, often responsible for impaired quality of life, are unpredictable in frequency and timing, but amenable to effective contemporary treatments, and infrequently progress to permanent AF. AF is not a major contributor to heart failure morbidity or a cause of arrhythmic sudden death; when treated, it is associated with low disease-related mortality, no different than for patients without AF. AF is an uncommon primary cause of death in HCM virtually limited to embolic stroke, supporting a low threshold for initiating anticoagulation therapy.

Atrial Fibrillation and Anticoagulation in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) represents a common inherited cardiac disorder with well-known complications Including stroke and sudden cardiac death. There is a recognised association between HCM and the development of AF. This review describes the epidemiology of AF within the HCM population and analyses the risk factors for the development of AF. It further discusses the outcomes associated with AF in this population, including the evidence in support of higher stroke risk in patients with HCM with AF compared with the general AF population. Finally, the evidence and recommendations for anticoagulation in this patient group are addressed.

Atrial Fibrillation in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disorder with a spectrum of clinical manifestations. Patients with HCM are predisposed to developing atrial fibrillation (AF) due primarily to advanced diastolic dysfunction and left atrial (LA) dilatation and remodelling. Atrial fibrillation causes a progressive symptomatic and functional decline, as well as increased thromboembolic risk and mortality, particularly in the setting of rapid ventricular rates and left ventricular outflow tract (LVOT) obstruction. The mainstay of management of AF in HCM is a combination of non-pharmacological lifestyle and risk factor modification, long-term anticoagulation, and rhythm control with antiarrhythmic medications. There is a growing body of evidence indicating that an early and aggressive rhythm control strategy may result in more favourable outcomes.