Hypertrophic cardiomyopathy and atrial fibrillation: the Cardiomyopathy/Myocarditis registry of the EURObservational Research Programme of the European Society of Cardiology
Authors: Mizia-Stec K , Gimeno Blanes J R G , Charron P , Elliott P , Kaski J P , Maggioni A L , Tavazzi L , Tendera M , Wybraniec M T , Caforio A 
Published: October 2022

Abstract

Background
Current guidelines for AF management underline a complex approach to detecting and treating atrial fibrillation (AF). Hypertrophic cardiomyopathy (HCM) is commonly associated with AF.

Purpose
To assess the clinical characteristic and prognosis in patients with HCM and AF.

Methods and results
Overall, 1739 adult patients with HCM (711/40.9% female; median age at diagnosis: 55.5 years) were enrolled in the EURObservational Research Programme – Cardiomyopathy/Myocarditis Long-Term Registry. Baseline clinical characteristics and adverse cardiovascular endpoints at 1-year follow-up were analysed.

Results
At baseline, AF was found in 478 (27.5%) subjects (paroxysmal: 54.7%, persistent: 17.6%, permanent: 27.7%). Newly diagnosed AF was identified during 1-year follow-up in 48 (2.8%) subjects with HCM.
The presence of AF was associated with higher age (59.6±13.8 vs 50.8±16.1, p&lt;0.001); BMI (27.7±5.1 vs 26.6±4.6 kg/m2, p&lt;0.001); more advanced NYHA class (NYHA I/II and III/IV: 75.1 and 24.9 vs 86.2 and 13.8%, p&lt;0.001); more frequent history of diabetes (14.6 vs 8.4%, p&lt;0.001); arterial hypertension 43.4 vs 34.6%, p&lt;0.001); renal impairment (15.4 vs 6.35%, p&lt;0.001); and history of sustained VT (10.8 vs 6.35%, p&lt;0.001). AF patients were characterized by lower left ventricular ejection fraction (LV EF) (59±12 vs 63±11%, P&lt;0.001), left atrium (LA) dilatation (48.9±9.1 vs 42.4±7.7%, p&lt;0.001), increased pulmonary artery systolic pressure (37.8±13.7 vs 29.6±12.6 mmHg, p&lt;0.001), distribution of LV hypertrophy (p=0.032) and more advanced LV diastolic dysfunction (p&lt;0.001).
On multivariate logistic regression analysis, independent predictors of AF in the HCM population were: age at enrolment (OR 1.068, P&lt;0.001); LVEF (OR 0.978, p&lt;0.001); and LA diameter (OR 1.094, p&lt;0.001).
Oral anticoagulation (OAC) was administered in 69.5% of patients with AF (vitamin K antagonist: 48.5%; direct OAC: 21%). ICD was implanted in 26.8% in AF and 16.9% in non-AF subjects (p&lt;0.001). PVI was performed in 9.9% of AF patients only.
The annual incidence of stroke/TIA was higher in AF than in the non-AF population (2.64 vs 0.85%, p=0.009). There was a trend towards increased death from any cause in the AF population (3.39 vs 1.74%, p=0.05). There were no differences in SCD-risk score between AF and non-AF subjects.

Conclusion
The study reveals a high prevalence of AF in patients with HCM that corresponds with more advanced symptoms, increased prevalence of comorbidities, structural and functional heart remodelling along with inadequate anticoagulation and a significant increase in the risk of stroke. The clinical characteristics of HCM-AF patients indicate that the ESC recommended complex AF approach “CC To ABC” is appropriate in this population.

Funding Acknowledgement
Type of funding sources: None.