Sinus rhythm restores ventricular function in patients with cardiomyopathy and no late gadolinium enhancement on cardiac magnetic resonance imaging who undergo catheter ablation for atrial fibrillation.

Atrial fibrillation (AF) and systolic heart failure (HF) frequently coexist. Restoration of sinus rhythm by catheter ablation may result in a variable improvement in left ventricular (LV) function. Late-gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging identifies irreversible structural change and may predict incomplete recovery of LV function. To prospectively select patients with AF and symptomatic HF but without LV LGE and report the impact of AF ablation on LV function. Patients with AF and symptomatic HF (LV ejection fraction <50%) resistant to at least 1 antiarrhythmic drug and prior electrical cardioversion underwent contrast-enhanced CMR. LGE-negative patients underwent pulmonary vein isolation and left atrial roof line with continued antiarrhythmic medications until follow-up CMR 6 months postablation. Sixteen patients (aged 52 ± 11 years; mean AF duration 37 ± 39 months; left atrial size 44 ± 13 mL/m(2)) underwent AF ablation. At 6 months, 15 of the 16 patients maintained sinus rhythm and underwent CMR. LV ejection fraction increased from 40% ± 10% at baseline to 60% ± 6% (P < .001) and LV end-systolic volume index decreased from 52 ± 12 to 36 ± 9 mL/m(2) (P < .001). Left atrial size decreased from 44 ± 13 to 36 ± 11 mL/m(2) (P < .01). In patients with AF and LV dysfunction in the absence of LGE on CMR, ventricular function normalizes following the restoration of sinus rhythm. CMR may assist in the selection of patients with combined AF and systolic HF most likely to benefit from catheter ablation.

Ling LH ，Taylor AJ ，Ellims AH ，Iles LM ，McLellan AJ ，Lee G ，Kumar S ，Lee G ，Teh A ，Medi C ，Kaye DM ，Kalman JM ，Kistler PM ... -  《-》

Atrial Remodeling Following Catheter Ablation for Atrial Fibrillation-Mediated Cardiomyopathy: Long-Term Follow-Up of CAMERA-MRI Study.

This study sought to determine the long-term right atrial (RA) electrical and structural changes in a subgroup from the CAMERA-MRI (Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction-Magnetic Resonance Imaging) study. Catheter ablation (CA) is successful in restoring ventricular function in patients with atrial fibrillation (AF) and otherwise unexplained cardiomyopathy, as demonstrated in the randomized study of CA versus rate control (CAMERA-MRI). It is unknown if this is associated with atrial remodeling. Detailed electroanatomical (EA) mapping of the RA using CARTO3 and a force sensing catheter was performed at initial CA and electively at least 12 months after CA in patients with >90% reduction in AF burden following ablation. Bipolar voltage, fractionation, and conduction velocity were collected in 4 segments together with echo and cardiac magnetic resonance imaging. Fifteen patients (mean age 59.1 ± 6.8 years) underwent repeat RA EA mapping. At a mean follow-up of 23.4 ± 11.9 months, left ventricular (LV) ejection fraction improved from 33.6 ± 3.2% to 54.1 ± 3.2% (p = 0.001), RA area decreased from 28.4 ± 2.0 cm2 to 20.8 ± 1.2 cm2 (p < 0.001), and left atrial area decreased from 32.9 ± 2.3 cm2 to 26.8 ± 1.4 cm2 (p = 0.007). On EA mapping, RA bipolar voltage increased from 1.6 ± 0.1 mV to 1.9 ± 0.1 mV (p = 0.04). Tissue voltage increased across all regions, which achieved statistical significance at the posterior (p = 0.002) and septal (p = 0.01) segments. There was a significant decrease in complex fractionated electrograms from 21.7 ± 3.5% to 8.3 ± 1.8% (p = 0.002); however, no significant change occurred in global or regional conduction velocities (p = 0.5). Recovery of atrial electrical and structural changes was observed following restoration of sinus rhythm and recovery of LV function in patients who underwent CA for persistent AF and LV systolic dysfunction. The randomized CAMERA MRI study demonstrated significant improvement in LV systolic function with AF ablation compared with rate control. The present study demonstrated reverse electrical and structural atrial recovery in concert with recovery of LV systolic function at 2 years post-AF ablation. This may partially explain the long-term success of CA in patients with AF and otherwise unexplained cardiomyopathy.

Sugumar H ，Prabhu S ，Voskoboinik A ，Young S ，Gutman SJ ，Wong GR ，Parameswaran R ，Nalliah CJ ，Lee G ，McLellan AJ ，Taylor AJ ，Ling LH ，Kalman JM ，Kistler PM ... -  《-》

Incidental LV LGE on CMR Imaging in Atrial Fibrillation Predicts Recurrence After Ablation Therapy.

This study sought to evaluate the prognostic significance of left ventricular late gadolinium enhancement (LV-LGE) incidentally found in atrial fibrillation (AF) patients who undergo ablation therapy. LV-LGE provides prognostic information in patients with ischemic and nonischemic cardiomyopathies. However, data on the clinical significance of incidental LV-LGE in the AF population are limited. A total of 778 patients who were referred for radiofrequency ablation of AF underwent cardiac magnetic resonance examinations between June 2006 and January 2013. Patients with a history of myocardial infarction or ablation therapy were excluded. The presence of LV-LGE was assessed by experienced imaging physicians. Patients were followed for arrhythmia recurrence after the radiofrequency ablation procedure. Of 598 patients included in the study, 60% were men with a mean age of 64 years and a median AF duration of 25 months. LV-LGE was detected in 39 patients (6.5%). There were 240 arrhythmia recurrences observed involving 40% of patients over a median follow-up period of 52 months. On univariate analysis, age (hazard ratio [HR]: 1.02; 95% confidence interval [CI]: 1.00 to 1.03), male sex (HR: 0.63; 95% CI: 0.47 to 0.86), diabetes (HR: 1.53; 95% CI: 1.03 to 2.27), CHADS2 score (HR: 1.19; 95% CI: 1.04 to 1.36), CHA2DS2-VASc score (HR: 1.18; 95% CI: 1.08 to 1.30), left atrial (LA) fibrosis (HR: 1.66; 95% CI: 1.41 to 1.96), LV-LGE (HR: 1.83; 95% CI: 1.11 to 3.03), persistent AF (HR: 1.52; 95% CI: 1.11 to 2.09), and LA area (HR: 1.03; 95% CI: 1.01 to 1.05) were significantly associated with arrhythmia recurrence. The recurrence rate was 69% in patients with LV-LGE compared with 38% in patients without LV-LGE (p < 0.001). In a multivariate model, LA fibrosis and LV-LGE were independent predictors of arrhythmia recurrence. In AF patients without history of myocardial infarction, LV-LGE is a significant independent predictor of arrhythmia recurrence after ablation therapy.

Suksaranjit P ，Akoum N ，Kholmovski EG ，Stoddard GJ ，Chang L ，Damal K ，Velagapudi K ，Rassa A ，Bieging E ，Challa S ，Haider I ，Marrouche NF ，McGann CJ ，Wilson BD ... -  《-》

Cardiac magnetic resonance T1 mapping of left atrial myocardium.

Cardiac magnetic resonance (CMR) T1 mapping is an emerging tool for objective quantification of myocardial fibrosis. To (a) establish the feasibility of left atrial (LA) T1 measurements, (b) determine the range of LA T1 values in patients with atrial fibrillation (AF) vs healthy volunteers, and (c) validate T1 mapping vs LA intracardiac electrogram voltage amplitude measures. CMR imaging at 1.5 T was performed in 51 consecutive patients before AF ablation and in 16 healthy volunteers. T1 measurements were obtained from the posterior LA myocardium by using the modified Look-Locker inversion-recovery sequence. Given the established association of reduced electrogram amplitude with fibrosis, intracardiac point-by-point bipolar LA voltage measures were recorded for the validation of T1 measurements. The median LA T1 relaxation time was shorter in patients with AF (387 [interquartile range 364-428] ms) compared to healthy volunteers (459 [interquartile range 418-532] ms; P < .001) and was shorter in patients with AF with prior ablation compared to patients without prior ablation (P = .035). In a generalized estimating equations model, adjusting for data clusters per participant, age, rhythm during CMR, prior ablation, AF type, hypertension, and diabetes, each 100-ms increase in T1 relaxation time was associated with 0.1 mV increase in intracardiac bipolar LA voltage (P = .025). Measurement of the LA myocardium T1 relaxation time is feasible and strongly associated with invasive voltage measures. This methodology may improve the quantification of fibrotic changes in thin-walled myocardial tissues.

Beinart R ，Khurram IM ，Liu S ，Yarmohammadi H ，Halperin HR ，Bluemke DA ，Gai N ，van der Geest RJ ，Lima JA ，Calkins H ，Zimmerman SL ，Nazarian S ... -  《-》

Association of left ventricular late gadolinium enhancement with left atrial low voltage areas in patients with atrial fibrillation.

Stegmann C ，Jahnke C ，Paetsch I ，Hilbert S ，Arya A ，Bollmann A ，Hindricks G ，Sommer P ... -  《-》