title: Lone Atrial Fibrillation Is Associated With Impaired Left Ventricular Energetics That Persists Despite Successful Catheter Ablation.
abstract: BACKGROUND
  Lone atrial fibrillation (AF) may reflect a subclinical cardiomyopathy that persists after sinus rhythm (SR) restoration, providing a substrate for AF recurrence. To test this hypothesis, we investigated the effect of restoring SR by catheter ablation on left ventricular (LV) function and energetics in patients with AF but no significant comorbidities.
  
  
  METHODS
  Fifty-three patients with symptomatic paroxysmal or persistent AF and without significant valvular disease, uncontrolled hypertension, coronary artery disease, uncontrolled thyroid disease, systemic inflammatory disease, diabetes mellitus, or obstructive sleep apnea (ie, lone AF) undergoing ablation and 25 matched control subjects in SR were investigated. Magnetic resonance imaging quantified LV ejection fraction (LVEF), peak systolic circumferential strain (PSCS), and left atrial volumes and function, whereas phosphorus-31 magnetic resonance spectroscopy evaluated ventricular energetics (ratio of phosphocreatine to ATP). AF burden was determined before and after ablation by 7-day Holter monitoring; intermittent ECG event monitoring was also undertaken after ablation to investigate for asymptomatic AF recurrence.
  
  
  RESULTS
  Before ablation, both LV function and energetics were significantly impaired in patients compared with control subjects (LVEF, 61% [interquartile range (IQR), 52%-65%] versus 71% [IQR, 69%-73%], P<0.001; PSCS, -15% [IQR, -11 to -18%] versus -18% [IQR, -17% to -19%], P=0.002; ratio of phosphocreatine to ATP, 1.81±0.35 versus 2.05±0.29, P=0.004). As expected, patients also had dilated and impaired left atria compared with control subjects (all P<0.001). Early after ablation (1-4 days), LVEF and PSCS improved in patients recovering SR from AF (LVEF, 7.0±10%, P=0.005; PSCS, -3.5±4.3%, P=0.001) but were unchanged in those in SR during both assessments (both P=NS). At 6 to 9 months after ablation, AF burden reduced significantly (from 54% [IQR, 1.5%-100%] to 0% [IQR 0%-0.1%]; P<0.001). However, LVEF and PSCS did not improve further (both P=NS) and remained impaired compared with control subjects (P<0.001 and P=0.003, respectively). Similarly, there was no significant improvement in atrial function from before ablation (P=NS), and this remained lower than in control subjects (P<0.001). The ratio of phosphocreatine to ATP was unaffected by heart rhythm during assessment and AF burden before ablation (both P=NS). It was unchanged after ablation (P=0.57), remaining lower than in control subjects regardless of both recovery of SR and freedom from recurrent AF (P=0.006 and P=0.002, respectively).
  
  
  CONCLUSIONS
  Patients with lone AF have impaired myocardial energetics and subtle LV dysfunction, which do not normalize after ablation. These findings suggest that AF may be the consequence (rather than the cause) of an occult cardiomyopathy, which persists despite a significant reduction in AF burden after ablation.
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Rohan S
authors.initials: RS
authors.lastname: Wijesurendra
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Alexander
authors.initials: A
authors.lastname: Liu
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Christian
authors.initials: C
authors.lastname: Eichhorn
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Rina
authors.initials: R
authors.lastname: Ariga
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Eylem
authors.initials: E
authors.lastname: Levelt
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: William T
authors.initials: WT
authors.lastname: Clarke
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Rodgers
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Theodoros D
authors.initials: TD
authors.lastname: Karamitsos
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Yaver
authors.initials: Y
authors.lastname: Bashir
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Matthew
authors.initials: M
authors.lastname: Ginks
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Kim
authors.initials: K
authors.lastname: Rajappan
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Tim
authors.initials: T
authors.lastname: Betts
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: Ferreira
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.).
authors.forename: Stefan
authors.initials: S
authors.lastname: Neubauer
authors.affiliation: From Division of Cardiovascular Medicine, University of Oxford, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N., B.C.); University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK (R.S.W., A.L., C.E., R.A., E.L., W.T.C., C.T.R., T.D.K., V.M.F., S.N.); and Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK (Y.B., M.G., K.R., T.B.). barbara.casadei@cardiov.ox.ac.uk.
authors.forename: Barbara
authors.initials: B
authors.lastname: Casadei
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications* / Q000503:physiopathology*; D009202:Cardiomyopathies / Q000150:complications; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods; D004452:Echocardiography / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology; D006333:Heart Failure / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology
keywords: arrhythmias, cardiac; atrial fibrillation; catheter ablation; magnetic resonance imaging; magnetic resonance spectroscopy; ventricular dysfunction, left