Predictors and Mechanisms of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

The impact of diabetes mellitus on cardiac function assessed by magnetic resonance imaging in patients with hypertrophic cardiomyopathy

BACKGROUND

The adverse prognostic impact of diabetes on hypertrophic cardiomyopathy (HCM) is poorly understood. We sought to explore the underlying mechanisms in terms of structural and functional remodelling in HCM patients with coexisting diabetes (HCM-DM).

METHODS

A total of 45 HCM-DM patients were retrospectively included. Isolated HCM controls (HCM patients without diabetes) were matched to HCM-DM patients in terms of maximal wall thickness, age, and gender distribution. Left ventricular (LV) and atrial (LA) performance were evaluated using cardiac magnetic resonance feature tracking strain analyses. The associations between diabetes and LV/LA impairment were investigated by univariable and multivariable linear regression.

RESULTS

Compared with the isolated HCM controls, the HCM-DM patients had smaller end-diastolic volume and stroke volume, lower ejection fraction, larger mass/volume ratio and impaired strains in all three directions (all P < 0.05). In terms of the LA parameters, HCM-DM patients presented impaired LA reservoir and conduit strain/strain rate (all P < 0.05). Among all HCM patients, comorbidity with diabetes was independently associated with a low LV ejection fraction (β = - 6.05, P < 0.001) and impaired global longitudinal strain (β = 1.40, P = 0.007). Moreover, compared with the isolated HCM controls, HCM-DM patients presented with more myocardial fibrosis according to late gadolinium enhancement, which was an independent predictor of impaired LV global radial strain (β = - 45.81, P = 0.008), LV global circumferential strain (β = 18.25, P = 0.003), LA reservoir strain (β = - 59.20, P < 0.001) and strain rate (β = - 2.90, P = 0.002).

CONCLUSIONS

Diabetes has adverse effects on LV and LA function in HCM patients, which may be important contributors to severe manifestations and outcomes in those patients. The present study strengthened the evidence of the prevention and management of diabetes in HCM patients.

The Association of Epicardial Adipose Tissue Volume and Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: As Assessed by Cardiac MR

BACKGROUND

Epicardial adipose tissue (EAT) is a metabolically active visceral fat linked to cardiovascular disease. Prior studies demonstrated the predictive value of EAT volume (EATV) in atrial fibrillation (AF) among hypertrophic obstructive cardiomyopathy patients.

PURPOSE

To investigate the association between EATV and AF in hypertrophic cardiomyopathy (HCM).

STUDY TYPE

Retrospective.

POPULATION

Two hundred and twenty-four HCM patients (including 79 patients with AF and 145 patients without AF, 154 men) and 80 healthy controls (54 men).

FIELD STRENGTH/SEQUENCE

3.0 T scanner; balanced steady-state free precession (SSFP) cine sequence, gradient echo.

ASSESSMENT

EAT thickness was assessed in the 4-chamber and basal short-axis planes. EAT volume was calculated by outlining the epicardial border and visceral pericardium layer on short-axis cine images.

STATISTICAL TESTS

Shapiro-Wilk test, Student's t test or the Mann-Whitney U test, chi-square test or Fisher's exact test, Multivariate linear regression analyses, Multivariable binary logistic regression analysis. Intraclass correlation coefficient. Significance was determined at P < 0.05.

RESULTS

EATV and EAT volume index (EATVI) were significantly greater in HCM patients with AF than those without AF (126.6 ± 25.9 mL vs. 90.5 ± 24.5 mL, and 73.0 ± 15.9 mL/m2 vs. 51.3 ± 13.4 mL/m2). EATVI was associated with AF in multivariable linear regression analysis among HCM patients (β = 0.62). Multivariable logistic regression analysis revealed that compared to other indicators, the area under curve (AUC) of EATVI was 0.86 (cut-off, 53.9 mL/m2, 95% CI, 0.80-0.89), provided a better performance, with the sensitivity of 96.2% and specificity of 58.6%. The combined model exhibited superior association with AF presence compared to the clinical model (AUC 0.96 vs. 0.76) and the imaging model (AUC 0.96 vs. 0.93).

DATA CONCLUSION

EATVI was associated with AF. EATVI was significantly correlated with incident AF, and provided a better performance in HCM patients compared to other indicators.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

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.

Catheter ablation in Asian patients with atrial fibrillation and hypertrophic cardiomyopathy: electrophysiological characteristics of recurrence and long-term clinical outcomes

Background

Catheter ablation (CA) is a treatment strategy for atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). We investigated the electrophysiological characteristics of recurrence in a tertiary referral center and compared long-term clinical outcomes after CA therapy with patients who did not undergo CA.

Methods

Patients with HCM and AF who underwent CA (group 1, n = 60) or pharmacological treatment (group 2, n = 298) between 2006 and 2021 were enrolled in this study. The baseline characteristics and electrophysiological characteristics of group 1 patients were examined to elucidate the reason for the recurrence of AF after CA therapy. The clinical results of the patients in Group 1 and Group 2 were compared using a propensity score (PS)-matched method.

Results

The most common cause of recurrence was pulmonary vein reconnection (86.5%), followed by non-pulmonary vein triggers (40.5%), cavotricuspid isthmus flutter (29.7%), and atypical flutter (24.3%). Thyroid disease (HR, 14.713; P < 0.01), diabetes (HR, 3.074; P = 0.03), and non-paroxysmal AF (HR, 4.012; P = 0.01); these factors independently predicted recurrence. After the first recurrence, patients who underwent repeat CA showed a better arrhythmia-free state (74.1%) than those who underwent drug escalation therapy (29.4%, P < 0.01). After matching, PS-group 1 patients showed significantly better outcomes in all-cause mortality, heart failure hospitalization, and left atrial reverse remodeling than PS-group 2 patients.

Conclusions

Patients who underwent CA showed better clinical outcomes than those who underwent drug therapy. The main predictors of recurrence were thyroid disease, diabetes, and non-paroxysmal AF.

Association between left ventricular reverse remodeling and long-term outcomes after alcohol septal ablation for hypertrophic obstructive cardiomyopathy

There is a paucity of data regarding the effect of left ventricular (LV) reverse remodeling (r-LVR) on diastolic function and outcomes after alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM). The aim of this study was to identify the impact of r-LVR on the outcome and the predictors of such changes after ASA. Eighty-seven patients (57.5% men) were enrolled and underwent both echocardiography and cardiovascular magnetic resonance (CMR) imaging at baseline and 27 months after the procedure. The study population was divided into two groups by the degree of r-LVR. Compared to the greater r-LVR group, the lesser r-LVR group had a significantly larger LV mass (LVM) and lower diastolic function parameters at baseline. The greater r-LVR group had significantly greater LVM regression and improvement of diastolic function after ASA. Kaplan‒Meier analysis showed significantly worse composite events in the lesser r-LVR group after ASA (P = 0.016). After adjusting for multiple clinical variables, r-LVR was associated with an improved E/e' (β = 0.390, p < 0.001) and reduced events (hazard ratio: 0.795; 95% confidence interval (CI), 0.644-0.983; p = 0.034). Preablation LVM was associated with a decreased probability of r-LVR (β = -0.228, p = 0.021) and diastolic function improvement (β= -0.245, p = 0.006). r-LVR was associated with long-term outcome benefit in patients with HOCM. Preablation LVM prevented LV from favoring reverse remodeling and thus may be a potential parameter for risk stratification and prognosis after ASA treatment.

Acute myocardial infarction occurring after hypertrophic obstructive cardiomyopathy with paroxysmal atrial fibrillation: a case report

Atheromatous plaque rupture and coronary artery stenosis/occlusion are leading causes of acute myocardial infarction (AMI). Other reasons for AMI are frequently overlooked. We report a rare case of AMI occurring after hypertrophic obstructive cardiomyopathy with paroxysmal atrial fibrillation. Although the patient showed multiple lead ST-T changes on an electrocardiogram and elevated circulating cardiac troponin I concentrations, no stenotic lesions were observed by repeated invasive coronary angiography examinations. Hypertrophic obstructive cardiomyopathy with paroxysmal atrial fibrillation was suspected as the primary cause of AMI. The patient received radiofrequency catheter ablation therapy and was free of atrial fibrillation and myocardial infarction 1 year postoperatively. The clinical management and outcome of the patient are also discussed.

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

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

Clinical Translation of Three-Dimensional Scar, Diffusion Tensor Imaging, Four-Dimensional Flow, and Quantitative Perfusion in Cardiac MRI: A Comprehensive Review

Cardiovascular magnetic resonance (CMR) imaging is a versatile tool that has established itself as the reference method for functional assessment and tissue characterisation. CMR helps to diagnose, monitor disease course and sub-phenotype disease states. Several emerging CMR methods have the potential to offer a personalised medicine approach to treatment. CMR tissue characterisation is used to assess myocardial oedema, inflammation or thrombus in various disease conditions. CMR derived scar maps have the potential to inform ablation therapy—both in atrial and ventricular arrhythmias. Quantitative CMR is pushing boundaries with motion corrections in tissue characterisation and first-pass perfusion. Advanced tissue characterisation by imaging the myocardial fibre orientation using diffusion tensor imaging (DTI), has also demonstrated novel insights in patients with cardiomyopathies. Enhanced flow assessment using four-dimensional flow (4D flow) CMR, where time is the fourth dimension, allows quantification of transvalvular flow to a high degree of accuracy for all four-valves within the same cardiac cycle. This review discusses these emerging methods and others in detail and gives the reader a foresight of how CMR will evolve into a powerful clinical tool in offering a precision medicine approach to treatment, diagnosis, and detection of disease.

Assessment of atrial function by myocardial deformation techniques in hypertrophic cardiomyopathy

BACKGROUND

Diastolic dysfunction in hypertrophic cardiomyopathy (HCM) is common, but its assessment is difficult using conventional echocardiography.

AIMS

To assess left atrial (LA) function in HCM by longitudinal strain and determine its role in understanding of symptoms.

METHODS

We studied 144 patients divided into 3 age- and sex-matched groups: 48 consecutive patients with HCM, 48 control subjects, and 48 athlete subjects. We assessed LA function by conventional echocardiographic parameters and by longitudinal atrial strain (early-diastolic left atrial strain during reservoir phase [LASr]; end-diastolic left atrial strain during conduit phase; end-systolic peak of the left atrial strain during contraction phase).

RESULTS

NYHA classification was as follows in HCM group: I in 46%, II in 31%, III in 19%, and IV in 4%. Conventional echocardiographic parameters of diastolic function were depressed in the HCM group as compared to the control and athlete groups, but not related to symptoms. All longitudinal atrial strain parameters were significantly reduced in HCM group as compared to two groups (P < .0001). LASr was significantly correlated to peak VO2 (r = 0.44, P = .01) and was the best parameter for detecting symptomatic patients presenting with HCM, with a cutoff value of 15%: Sensitivity was 71%, specificity was 79%, PPV was 77%, and NPV was 73%.

CONCLUSION

Assessment of LA function in HCM is feasible using longitudinal strain, and this technique is more reliable than conventional echocardiographic parameters for the understanding of determinants of symptoms.