Interatrial block as electrocardiographic predictive sign for atrial fibrillation in patients hospitalized in Internal Medicine Departments

This study evaluated the correlation between interatrial block (IAB) and atrial fibrillation (AF) among patients admitted to our Internal Medicine Unit: 110 (group 1) were identified with electrocardiograms both in sinus rhythm and AF, and 123 (group 2) constantly in sinus rhythm. In both groups we analyzed: the presence of partial (P≥120 msec) or advanced (P>120 msec and biphasic in D2, D3, aVF) IAB, and the main electrocardiographic and clinical features. Age and gender between the two groups were similar. IAB was present in 89/110 (80.91%) in group 1 and 26/123 (21.13%) in group 2 (P=<0.01); partial in 50/110 (45.45%) and 19/123 (15.7%) in group 1 and 2 respectively (P<0.01), advanced in 39/110 (35.45%) and 7/123 (5.69%) (P<0.019). The correlation between IAB and AF was significant (P<0.001); 36 (65.4%) patients out of 55 with atrial echo dilatation had IAB and 14 (25.4%) had deep terminal negativity of P-wave in V1 (DTNPV1) >0.1 mV (P<0.01). IAB represents a reliable predictor of AF; moreover, the sensitivity of the IAB in detecting atrial dilatation is higher than the DTNPV1 >0.1 mV.