Left atrial strain for predicting arrhythmia recurrence after atrial fibrillation ablation: cardiac magnetic resonance rapid strain vs. feature tracking strain

Background Global left atrial (LA) strain is a predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). Recently, novel rapid LA strain assessment approaches have emerged: LA long axis strain and LA AV junction strain. Currently, it remains unknown whether these rapid strain approaches can predict AF recurrence after AF ablative therapy and hence may be a simple alternative for the cumbersome LA feature tracking strain analysis. Purpose The present study focusses on the predictive value of different atrial strain quantification methods in relation to AF recurrence after PVI. Rapid LA strain analysis is compared to LA feature tracking strain in AF patients. Methods A total of 58 AF patients (78% paroxysmal AF, 64% male, mean age 61±7 years) undergoing first radiofrequency PVI ablation were included. Prior to ablation, all patients underwent cardiac magnetic resonance imaging being in sinus rhythm. LA rapid strain (long axis strain and AV junction strain) and LA feature tracking strain were derived from 2-chamber and 4-chamber cine CMR images. All patients were routinely followed up for arrhythmia recurrence through 12-lead ECGs, mobile-based one-lead ECGs, and/or Holter monitoring. Results After one year follow-up, arrhythmia recurrence (after the 90-day blanking period) was observed in 21 patients (36%), occurring after a median of 159 (119–320) days. LA long axis strain, AV junction strain, and feature tracking strain were all significantly reduced in patients with AF recurrence compared to patients without AF recurrence (long axis strain: −19.96±11.03% vs. −28.18±9.93%, P=0.005; AV junction strain: −18.08±9.69% vs. −25.60±8.79%, P=0.004; feature tracking strain: −12.54±4.16% vs. −15.94±3.50%, P=0.002, respectively, figure A to C). ROC analysis identified LA feature tracking strain as having the highest area under the curve (AUC) for predicting AF recurrence after ablative therapy (AUC: 0.75 for LA feature tracking strain, 0.71 for LA long axis strain, 0.70 for AV junction strain, figure D). Both LA rapid strain methods had a significant correlation with LA feature tracking strain (LA long axis strain vs. LA feature tracking strain, r=0.76, P<0.001 and LA AV junction strain vs. LA feature tracking strain, r=0.77, P<0.001). Conclusion LA rapid strain and LA feature tracking strain both have clinically relevant predictive power for prediction of AF recurrence after index PVI in AF patients. Considering the ease of LA rapid strain analysis, this method may be a valuable parameter to assess in clinical practice. FUNDunding Acknowledgement Type of funding sources: None. Figure 1

Prognostic value of fast semi-automated left atrial long-axis strain analysis in hypertrophic cardiomyopathy

Background The prognostic value of left atrial (LA) size and function in hypertrophic cardiomyopathy (HCM) is well recognized, but LA function is difficult to routinely analyze. Fast LA long-axis strain (LA-LAS) analysis is a novel technique to assess LA function on cine cardiovascular magnetic resonance (CMR). We aimed to assess the association between fast LA-LAS and adverse clinical outcomes in patients with HCM. Methods 359 HCM patients and 100 healthy controls underwent routine CMR imaging. Fast LA-LAS was analyzed by automatically tracking the length between the midpoint of posterior LA wall and the left atrioventricular junction based on standard 2- and 4-chamber balanced steady-state free precession cine-CMR. Three strain parameters including reservoir strain (εs), conduit strain (εe), and active strain (εa) were assessed. The endpoint was set as composite adverse events including cardiovascular death, resuscitated cardiac arrest, sudden cardiac death aborted by appropriate implantable cardioverter-defibrillator discharge, and hospital admission related to heart failure. Results During an average follow-up of 40.9 months, 59 patients (19.7%) reached endpoints. LA strains were correlated with LA diameter, LA volume index (LAVI) and LA empty fraction (LAEF) (all p < 0.05). In the stepwise multivariate Cox regression analysis, εs and εe (hazard ratio, 0.94 and 0.89; p = 0.019 and 0.006, respectively) emerged as independent predictors of the composite adverse events. Fast LA εs and LA εe are stronger prognostic factors than LA size, LAVI and the presence of left ventricular late gadolinium enhancement. Conclusions Fast LA reservoir and conduit strains are independently associated with adverse outcomes in HCM.

Fast manual long-axis strain assessment provides optimized cardiovascular event prediction following myocardial infarction

Aims Cardiovascular magnetic resonance feature tracking (CMR-FT) global longitudinal strain (GLS) provides incremental prognostic value following acute myocardial infarction (AMI) but requires substantial post-processing. Alternatively, manual global long-axis strain (LAS) can be easily assessed from standard steady state free precession images. We aimed to define the prognostic value of LAS in a large multicentre study in patients following AMI. Methods and results A total of 1235 patients with myocardial infarction [n = 795 with ST-elevation myocardial infarction (STEMI) and 440 with non-ST-elevation myocardial infarction (NSTEMI)] underwent cardiovascular magnetic resonance imaging after primary percutaneous coronary intervention in eight centres across Germany. Assessment of LAS was performed in a blinded core-laboratory measuring the systolic shortening between the epicardial apical border and the middle of a line connecting the origins of the mitral leaflets. Primary clinical endpoint was the occurrence of major adverse clinical events (MACE) including death, reinfarction, and congestive heart failure within 1 year after AMI. During 1-year follow-up, 76 patients suffered from MACE. Impaired LAS was associated with higher MACE occurrence both in STEMI (P < 0.001) and NSTEMI (P = 0.001) patients. Association of LAS remained significant (P = 0.017) after correction for univariate significant parameters for MACE prediction. C-statistics revealed incremental value of additional LAS assessment for optimized event prediction compared with left ventricular ejection fraction (MACE P = 0.044; mortality P = 0.013) and a combination of established clinical and imaging parameters (MACE P = 0.084; mortality P = 0.027), but not CMR-FT GLS (MACE P = 0.075; mortality P = 0.380). Conclusion LAS provides software independent, widely available, easy and fast approximation of longitudinal left ventricular shortening early after reperfused AMI with incremental prognostic value beyond established risk stratification parameters. Clinical Trials.gov NCT00712101 and NCT01612312.