Diastolic Dysfunction and Risk of Atrial Fibrillation

Abstract

A trial fibrillation (AF) is the most common sustained arrhythmia, and its prevalence in the population is increasing. 1 Diastolic dysfunction shares many common risk factors with AF, including age, hypertension, 2-5 obesity, 6,7 and diabetes. 8,9 Like AF, diastolic dysfunction increases with age, 10 and patients given the diagnosis of diastolic dysfunction are more likely to have AF at the time. 11 Diastolic dysfunction has significant pathological effects on atrial structure and function, many of which are proarrhythmic. However, much remains to be learned about the specific mechanisms through which diastolic dysfunction ultimately promotes AF.Previous reviews have examined the broad association of diastolic dysfunction and AF. 12 In this review, we attempt to examine this association on a mechanistic level. We begin with a basic review of the physiology of diastolic function, with particular attention to the complex interaction between the atrium and the ventricle during diastole. We then provide an overview of some of the most common clinical methods to quantify diastolic function and highlight the strengths and weaknesses of these methods with regard to providing an accurate picture of this physiology. We describe how these methods are applied to diagnose diastolic dysfunction, including the development of a widely adopted classification scheme of diastolic dysfunction. We then review the limited clinical data available connecting diastolic dysfunction with the risk of incident, nonvalvular AF, with a focus on studies examining diastolic dysfunction in populations without structural heart disease-ie, with preserved systolic function in the absence of hypertrophic cardiomyopathic disease or congenital heart disease. Finally, we attempt to reconcile the results of these clinical studies with experimental data in both human, animal, and cellular models, to create a mechanistic link between diastolic dysfunction and pathological changes that increase the likelihood of AF. Atrial and Ventricular Diastolic DynamicsA number of excellent resources are available for more detailed review of the dynamics of ventricular diastole, including invasive 13 and noninvasive 14 -17 descriptions. Ventricular diastole is the period of the cardiac cycle that begins with the closure of the aortic valve and ends with mitral valve closure, during which the ventricle is filling with blood. It can be further divided into 4 sequential components: (1) isovolumic relaxation, (2) early rapid filling, (3) diastasis, and (4) atrial systole (late filling). Dynamically, none of the components is completely independent of each other, or the systolic function of the heart, and changes in one can influence the others in predictable and unpredictable ways.Essentially, there are 2 characteristics of ventricular function that contribute to diastolic function: relaxation (lusitropy) and compliance. Relaxation refers to the process by which the ventricular pressure drops after contraction to a level below that of the atrium, causing blood to flow dow...

Left Atrial Remodeling and Function in Advanced Heart Failure With Preserved or Reduced Ejection Fraction

“…We speculate that this may contribute to the higher prevalence of AF noted in HFpEF compared with HFrEF, despite smaller LA volumes, similar LA pressures, and similar HF severity and mortality risk. 44 The differences in LA structure-function also seem to influence how the LA copes with mitral regurgitation. With increasing regurgitation, LA pressure and wall stress increases much more steeply in HFpEF than in HFrEF, which may promote stretch-mediated atrial ectopy that plays a role in initiation of AF.…”

Effect of Obesity on the Prognostic Impact of Atrial Fibrillation in Heart Failure With Preserved Ejection Fraction

“…Theoretically, the presence of diastolic dysfunction, indicated by transmitral E/A ratio exceeding the median and increase in the left atrial dimension, is strongly associated with the development of AF. 24 Loss of atrial contraction may adversely affect hemodynamics, especially in patients with HFpEF, 25 although the prognostic impact of AF on the 2 types of HF is also controversial, 26-30 possibly because of inconsistency in the definition of HFpEF/HFrEF as well as variation of the observation period.…”

Pathophysiological and Clinical Approach to Cirrhotic Cardiomyopathy

“…Based on the severity of diastolic heart function, patients may be relatively asymptomatic. Diastolic dysfunction is an underlying factor in the development of atrial fibrillation where the pathomechanism is postulated to be due to an increased atrial volume load [6]. Despite these pathomechanisms, no convenient evidence can be evaluated on the relationship between cirrhosis and atrial fibrillation.…”

“…Nevertheless, regardless of clinical manifestation, diastolic heart failure is an independent risk factor for cardiovascular mortality in both symptomatic and asymptomatic patients [5]. Furthermore, diastolic dysfunction is an important underlying factor in the development of certain arrhythmias, especially in the genesis of atrial fibrillation [6]. In the case of CCM, appearance of electrophysiological abnormalities may result in an increased risk for the development of both atrial and ventricular rhythm disturbances.…”