Relationship between electrocardiographic interatrial blocks and echocardiographic indices of left atrial function in acute heart failure

The presence of an interatrial block (IAB) on surface ECG should be considered as a hallmark of atrial electrical remodelling. This is often accompanied by morphological abnormalities. We aimed to investigate the frequency of IAB and its relationship with the echocardiographic indices of left atrial (LA) remodelling in patients hospitalised with acute HF. Ninety-four consecutive HF patients underwent 12-lead ECG, transthoracic echocardiogram including a detailed study of the LA, and blood tests (including NT-proBNP) on the same day. Thirty-six patients were excluded from the analysis because of atrial fibrillation or rhythms other than sinus. Twenty-eight over 58 (48%) were males. Median age was 72 (IQR 60–82) years. The majority of patients (72%) were diagnosed as having an HF with reduced ejection fraction. Overall, 27 (46%) patients presented with an advanced III or IV NYHA functional class. Median plasma NT-proBNP was 3046 (IQR 1066–5460) pg/ml. Nearly, all the enrolled patients (90%) showed LA dilation. Nineteen patients (33%) presented with advanced IAB. There was a trend toward a more advanced age in patients with advanced IAB (median age 79 vs 68, p = 0.051). Moreover, they were more frequently treated with anticoagulants (42% vs 13%, p = 0.01), and they exhibited greater LA structural and functional remodelling documented by larger area (28 vs 26 cm², p = 0.04) and greater minimum LA volume index—LAVi (43 ± 16 vs 36 ± 10, p = 0.04). Advanced IAB resulted to be an independent determinant of LA area (Beta 3.49 (0.37–6.60), p = 0.03) and minimum LAVi (Beta 7.22 (0.15–14.30), p = 0.045), and vice versa. LA electrical and structural remodelling is highly prevalent in a non-selected cohort of patients with acute HF. Advanced IAB on surface ECG is present in a high percentage of cases. Patients with advanced IAB tend to be older, and they exhibit higher degrees of LA structural and functional remodelling.