Left Atrial Structure and Function in Atrial Fibrillation
Left Atrial Structure and Function in Atrial Fibrillation
Aims The complex relationship between left atrial (LA) structure and function, electrical burden of atrial fibrillation (AF) and stroke risk is not well understood. We aimed to describe LA structure and function in AF.
Methods and results Left atrial structure and function was assessed in 971 subjects enrolled in the echocardiographic substudy of ENGAGE AF-TIMI 48. Left atrial size, emptying fraction (LAEF), and contractile function were compared across AF types (paroxysmal, persistent, or permanent) and CHADS2 scores as an estimate of stroke risk. The majority of AF patients (55%) had both LA enlargement and reduced LAEF, with an inverse relationship between LA size and LAEF (R = −0.57, P < 0.001). With an increasing electrical burden of AF and higher CHADS2 scores, LA size increased and LAEF declined. Moreover, 19% of AF subjects had impaired LAEF despite normal LA size, and LA contractile dysfunction was present even among the subset of AF subjects in sinus rhythm at the time of echocardiography.
Conclusions In a contemporary AF population, LA structure and function were increasingly abnormal with a greater electrical burden of AF and higher stroke risk estimated by the CHADS2 score. Moreover, LA dysfunction was present despite normal LA size and sinus rhythm, suggesting that the assessment of LA function may add important incremental information in the evaluation of AF patients. Clinical Trial Registration: http://www.clinicaltrials.gov; ID = NCT00781391.
Atrial fibrillation (AF) is common, increasing in frequency, and is associated with an elevated risk for stroke and death. Recent therapeutic advances, including new oral anticoagulant agents and ablation techniques, provide significant improvement in the care of AF patients. However, identifying patients who are most and least likely to benefit from these therapies remains challenging even with current risk prediction tools. Understanding the relationship between cardiac structure and function, electrical burden, and stroke risk in AF may help refine patient selection for anticoagulation and/or rhythm control strategies. However, prior echocardiographic studies have yielded conflicting results regarding the association between cardiac structure, function, and stroke risk in AF. These studies primarily evaluated left atrial (LA) size, while increasing attention is now being given to LA function. Therefore, we evaluated LA size and function, according to the electrical burden of AF (paroxysmal, persistent, and permanent) as well as stroke risk expressed in the CHADS2 score (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke/TIA) in subjects enrolled in the Effective aNticoaGulation with factor xA next GEneration in AF-Thrombolysis In Myocardial Infarction 48 (ENGAGE AF-TIMI 48) study.
Abstract and Introduction
Abstract
Aims The complex relationship between left atrial (LA) structure and function, electrical burden of atrial fibrillation (AF) and stroke risk is not well understood. We aimed to describe LA structure and function in AF.
Methods and results Left atrial structure and function was assessed in 971 subjects enrolled in the echocardiographic substudy of ENGAGE AF-TIMI 48. Left atrial size, emptying fraction (LAEF), and contractile function were compared across AF types (paroxysmal, persistent, or permanent) and CHADS2 scores as an estimate of stroke risk. The majority of AF patients (55%) had both LA enlargement and reduced LAEF, with an inverse relationship between LA size and LAEF (R = −0.57, P < 0.001). With an increasing electrical burden of AF and higher CHADS2 scores, LA size increased and LAEF declined. Moreover, 19% of AF subjects had impaired LAEF despite normal LA size, and LA contractile dysfunction was present even among the subset of AF subjects in sinus rhythm at the time of echocardiography.
Conclusions In a contemporary AF population, LA structure and function were increasingly abnormal with a greater electrical burden of AF and higher stroke risk estimated by the CHADS2 score. Moreover, LA dysfunction was present despite normal LA size and sinus rhythm, suggesting that the assessment of LA function may add important incremental information in the evaluation of AF patients. Clinical Trial Registration: http://www.clinicaltrials.gov; ID = NCT00781391.
Atrial fibrillation (AF) is common, increasing in frequency, and is associated with an elevated risk for stroke and death. Recent therapeutic advances, including new oral anticoagulant agents and ablation techniques, provide significant improvement in the care of AF patients. However, identifying patients who are most and least likely to benefit from these therapies remains challenging even with current risk prediction tools. Understanding the relationship between cardiac structure and function, electrical burden, and stroke risk in AF may help refine patient selection for anticoagulation and/or rhythm control strategies. However, prior echocardiographic studies have yielded conflicting results regarding the association between cardiac structure, function, and stroke risk in AF. These studies primarily evaluated left atrial (LA) size, while increasing attention is now being given to LA function. Therefore, we evaluated LA size and function, according to the electrical burden of AF (paroxysmal, persistent, and permanent) as well as stroke risk expressed in the CHADS2 score (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke/TIA) in subjects enrolled in the Effective aNticoaGulation with factor xA next GEneration in AF-Thrombolysis In Myocardial Infarction 48 (ENGAGE AF-TIMI 48) study.
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