Left atrial strain measurement to predict new-onset atrial fibrillation in ST-elevation myocardial infarction patients

Abstract

Abstract Background/Introduction ST-elevation myocardial infarction (STEMI) remains a healthcare burden not only through increased mortality risk, but also development of chronic cardiac pathologies like atrial fibrillation (AF). Left atrial (LA) reservoir strain is a known predictor of incident AF in the general population. Purpose Our aim was to explore the additional prognostic value of LA reservoir strain measured by transthoracic echocardiography (TTE) in STEMI patients for new-onset atrial fibrillation (NOAF). Methods Data were analyzed retrospectively from an ongoing STEMI registry. Patients with previous myocardial infarction, AF, known history of heart failure, severe valvular pathology, suboptimal image quality, AF during TTE or missing follow-up were excluded. TTE was performed within 48 hours of hospitalization. LA reservoir strain was measured in apical 4-chamber view. LA strain <23% was used as cut-off value for impaired LA function as previously established. The endpoint was NOAF. Follow-up was censored at last patient visit or at 5 years. Results In total 1238 patients (mean age 60±12 years; 930 (75%) men) were included. After median follow-up of 22 months (IQR 12; 60) 106 (8.6%) patients developed NOAF, most events (71 (67%)) taking place within the first year after STEMI. Mean LA reservoir strain was more impaired in patients who developed NOAF as compared to those who did not (19.3 ± 8.1% versus 24.3 ± 8.8% respectively (p<0.001). Clinical and echocardiographical characteristics are shown in the table. Cumulative event-free survival rates at 1, 3 and 5 years in patients with preserved versus decreased LA strain were 97%, 95% and 93% versus 91%, 89% and 83% respectively (Log-rank X2 = 21.1; p<0.001; Figure). Factors significant on univariable Cox regression analysis (age, presence of chronic obstructive pulmonary disease, troponin levels, left ventricular end-diastolic diameter, interventricular septum diameter, left ventricular global longitudinal strain, LA volume index, LA reservoir strain, E/E’ ratio and right ventricular fractional area change) were included in multivariable model, where LA reservoir strain remained significantly associated with NOAF (HR 0.96 (0.93 – 0.99); p=0.015). Addition of LA strain provided incremental prognostic value over baseline clinical risk factors, traditional TTE parameters and left ventricular global longitudinal strain (X2 84.5 vs 88.8; p=0.013). Conclusion LA reservoir strain was associated with new-onset atrial fibrillation in STEMI patients after adjusting for relevant clinical and echocardiographic risk factors.TableFigure