Left atrial strain is a powerful predictor of atrial fibrillation recurrence after catheter ablation: study of a heterogeneous population with sinus rhythm or atrial fibrillation

Abstract Introduction Left atrial strain (LAs) shows correlation with atrial fibrosis and is a predictor of atrial fibrillation (AF) recurrence after transcatheter ablation. Little is known about LAs evolution after ablation. Purpose We sought to evaluate the atrial function with echocardiographic strain before and 6 months after AF ablation. Methods 65 consecutive patients undergoing radiofrequency or cryoballoon ablation for atrial fibrillation at our centre were enrolled. They underwent a transthoracic echocardiography before the procedure and at 6 months follow-up. 5 patients were excluded because of low quality images. Global left atrial strain during the reservoir phase (LASr) was calculated as a mean of the values obtained in 4 and 2 chamber apical view; the ventricular end-diastole was set as reference to allow the calculation both in patients in AF and sinus rhythm during the echocardiography. Recurrence was defined as any atrial arrhythmia episode lasting more than 30 seconds recorded on an EKG strip after the 3 months blanking period; all patients underwent a 24 hours EKG Holter after the blanking period to detect asymptomatic recurrence. Quality of life was assessed before the procedure and at follow-up with the EQ-5D-3L model. Results At 6 months 14 patients (13%) had AF recurrence. Patients with recurrence (AF-R) had similar baseline characteristics compared to those without recurrence (AF-NR) but the former had a longer history of AF (39±53 vs 85±94 months, p=0,018). LASr, LA volume and left ventricle ejection fraction (EF) were similar at baseline between groups. At follow-up LASr was significantly impaired in the AF-R group compared to AF-NR (14±6% vs 26±10% respectively, p<0,0001) whereas LA volume, LV end systolic volume and EF remained similar. Compared to baseline LASr worsened in patients experiencing AF recurrence (22±11% vs 14±6%, p=0.016) and this finding was consistent also in patients in sinus rhythm during both examinations (29±8 vs 17±7, p=0,005). Compared to baseline LASr (22±10% vs 26±10%, p=0.024), LV end-systolic volume (29±15 ml vs 22±6 ml, p=0,006) and EF (51±9% vs 58±18%, p=0,038) improved in the AF-NR group but the effect was driven mainly by patients restoring sinus rhythm. Both groups showed a significant improvement of the quality of life (55±23 vs 85±13, p<0,0001 AF-NR; 63±17 vs 80±12, p=0,012 AF-R). Conclusions Atrial fibrillation recurrence after transcatheter ablation is associated with significant left atrial strain worsening which indicates disease progression and may predispose to further long-term recurrences whereas a successful ablation has a protective effect on atrial function. Funding Acknowledgement Type of funding source: None

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Abstract 5664: Left Atrial Strain In Patients With Atrial Fibrillation: Relationship To Fibrosis By Delayed Enhancement-MRI

Circulation ◽

10.1161/circ.118.suppl_18.s_980-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Suman S Kuppahally ◽

Robert S Oakes ◽

Eric N Fish ◽

Eugene Kholmovski ◽

Sathya Vijayakumar ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Strain Rate ◽

Left Atrial ◽

Delayed Enhancement ◽

Left Atrial Strain ◽

Chamber View ◽

Strain And Strain Rate ◽

Procedural Success ◽

Atrial Strain

Introduction: The extent of left atrial (LA) wall fibrosis detected by delayed enhancement (DE)-cardiac MRI prior to catheter ablation of atrial fibrillation (AF) appears to predict procedural success. However, it is currently unknown how the degree of fibrosis affects atrial mechanical function. Methods: Prior to catheter ablation of AF, 31 patients underwent DE-CMRI and 2-dimensional transthoracic echocardiography. 3D segmentation of LA was performed and the degree of fibrosis was determined using a semi-automated quantification algorithm. Longitudinal mid-septal and mid-lateral LA wall velocity, strain and strain rate were measured during ventricular systole from the apical 4-chamber view by velocity vector imaging. Results : There was greater percent of fibrosis as LA maximum (R = 0.4, p = 0.05) and minimum (R=0.52, p = 0.008) volumes increased. Figure shows examples of DE-CMRI and strain curves (C) for two patients: Patient 1(A) with mild fibrosis and patient 2 (B) with extensive fibrosis. Patient 1 shows much larger strain than patient 2. Larger LA volumes correlated inversely with maximal LA mid-lateral systolic wall strain (p < 0.005). The percent fibrosis also correlated inversely with maximal LA mid-lateral systolic wall strain (R=0.56, p < 0.005) and the systolic strain rate (R = 0.58, p = 0.002). Conclusion: LA strain and strain rate can be assessed using standard echocardiographic gray scale images. LA strain is related to both atrial volumes and fibrosis, which are markers of atrial disease progression. This relationship may represent changes in the properties of LA substrate. These novel imaging approaches may be helpful in predicting outcomes in patients with AF.

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