Aims: The power of left atrial (LA) parameters for predicting adverse events in relatively low-risk groups is not fully understood. This study investigated whether the LA expansion index predicts heart failure (HF) and all-cause mortality in subjects with dyspnoea.
Methods and results: Echocardiography was performed to identify causes of dypnoea in 1735 patients. The LA expansion index was calculated as (Volmax - Volmin) × 100%/Volmin, where Volmax was defined as the maximal LA volume and Volmin was defined as the minimal LA volume. The endpoints were 2-year frequencies of HF hospitalization and all-cause mortality. Over a median follow-up of 2.7 years, 91 participants reached endpoints. Rates of adverse events were exponentially proportional to the LA expansion index. For predicting adverse events, the LA expansion index was better than the maximal indexed LA volume and tissue Doppler parameters. Hospitalization for HF was independently associated with age, LVEF, pulmonary artery systolic pressure, LA expansion index, and history of prior HF. All-cause mortality was associated with age, pulmonary artery systolic pressure, and LA expansion index. Compared with the highest quartile of the LA expansion index, the lowest quartile had a 3.1-fold higher hazard of HF events and a 17.8-fold higher hazard of all-cause mortality.
Conclusions: The LA expansion index predicts adverse events in patients with dyspnoea. The prognostic power of the index exceeds that of other well-established echocardiographic parameters such as E/e' and maximal indexed LA volume. Trial registration NCT01171040.
Keywords: All-cause mortality; Heart failure hospitalization; Left atrial expansion index; Maximal indexed left atrial volume.