The Stiff Left Atrium Is to Atrial Fibrillation as the Stiff Left Ventricle Is to Diastolic Heart Failure.

Abstract

Atrial fibrillation (AF) is the most common cardiovascular disorder present in as many as 9% of subjects aged ≥65 years and costing the United States >26 billion dollars a year. It causes significant morbidity and mortality with 750 000 hospitalizations each year and contributing to an estimated 130 000 deaths each year.1 Risk factors for AF such as obesity, diabetes mellitus, coronary artery disease, heart failure, renal disease, heavy alcohol use, sleep apnea, and untreated or uncontrolled hypertension are also the risk factors for both systolic and diastolic heart failure.1 See Article by Khurram et al Therapeutic challenges can be appreciated from a recent trial in patients with paroxysmal AF that found antiarrhythmic therapy to be only 46% effective in preventing recurrence at 6 to 12 months compared with catheter ablation that had a 60% efficacy after the first ablation procedure.2 However, AF recurrences following pulmonary vein isolation procedure are less symptomatic.3 Multiple ablation procedures are also often required. Therefore, guidelines recommend left atrial (LA) ablation for paroxysmal AF after failure of at least 1 antiarrhythmic therapy.4 Atrial fibrosis contributes to AF probably because of disruption of normal electric conduction allowing establishment of the reentry circuit substrate. LA fibrosis can be detected by cardiac magnetic resonance (CMR) imaging as delayed gadolinium enhancement.5 Increased LA scar burden also predicts recurrence of AF. However, development of focally placed LA scar after ablation is associated with reduced LA function.6 LA scar burden is likely associated with increased LA stiffness similar to the decreased compliance of a scarred left ventricle (LV) both in ischemic cardiomyopathy as well as in nonischemic cardiomyopathy and in infiltrative/restrictive cardiomyopathy.7 Earlier studies have demonstrated an inverse relationship …