Left atrial strain at CMR is a strong independent prognostic predictor in DCM, superior to LV-GLS, LVEF and LAVI, and incremental to LGE

Abstract

Abstract Background The left atrium (LA) is an early sensor of left ventricular (LV) dysfunction. LA size and new-onset atrial fibrillation (AF) are associated with an increased risk of mortality and heart failure (HF) progression in patients with dilated cardiomyopathy (DCM). Whether abnormal LA strain measured at cardiac magnetic resonance (CMR) – a new technology to study atrial function – may predict overall outcome in DCM – either or not leading to new onset AF – remains completely unknown. Purpose To determine the prognostic value of CMR derived LA strain in DCM patients. Methods A total of 488 DCM patients (age 54 [46–62] years, 61% male) undergoing CMR were prospectively enrolled in the Maastricht Cardiomyopathy Registry between 2004 and 2018. Outcome consisted of the combination of sudden or cardiac death, HF hospitalization or life-threatening arrhythmias. LA reservoir (passive LA filling), conduit (passive LV filling), and booster strain (active LV filling) were measured using feature tracking strain analysis of the 2- and 4-chamber long-axis cines (Figure 1). Given the non-linearity of continuous variables, cubic spline analysis was performed to dichotomize. Results Seventy out of 488 DCM patients (14%) reached the endpoint (follow-up 6 [4–9] years). Age, NYHA class ≥3, late gadolinium enhancement (LGE) presence, LV ejection fraction (EF), LA volume index (LAVI), LV global longitudinal strain (GLS), and LA reservoir and conduit strain were univariably associated with worse outcome (all p-values <0.02). LA conduit strain was superior to reservoir strain to predict outcome. LA conduit strain, NYHA class ≥3 and LGE remained associated in the multivariable model (Figure 2A), while age, NTproBNP, LVEF, LA ejection fraction, LAVI and LV-GLS did not. Adding LA conduit strain to NYHA class and LGE significantly improved the calibration, accuracy, and reclassification of the prediction model (p<0.05). In patients without known AF and sinus rhythm (n=425) during CMR, 10% developed new-onset AF (paroxysmal or persistent) at long-term. Higher age, male sex, NYHA class ≥3, higher LAVI and impaired booster strain were all univariably associated with new-onset AF. Age and impaired booster strain remained as independent predictors of new-onset AF in the multivariable analysis (Figure 2B). Conclusions LA conduit strain on CMR is a strong independent prognostic predictor in DCM, superior to LV-GLS, LVEF and LAVI, and incremental to LGE. In addition, LA booster strain is an independent predictor of new-onset AF. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Netherlands Cardiovascular Research Initiative, an initiative with support of the Dutch Heart Foundation