Objective:

It is called advanced interatrial block (IAB) to the existence of a P wave ≥ 120 ms and biphasic ± in the lower leads II-III-VF of the surface electrocardiogram (ECG), which constitutes a significant predictive factor for the development of atrial fibrillation. Recently, four patterns of atypical aIAB (At-IAB) have been described based on the morphology and duration of the P wave, but it’s unknown if they share the same pathogenesis and clinical characteristics.

Method:

An observational, descriptive and retrospective study was performed with patients, visited in cardiology, who have a sinus rhythm and with aIAB. The analyzed variables were obtained from the computerized clinical history. The analysis of the P wave was made by increasing the size of the ECG and by electronic calipers. Statistical analysis was performed with SPSS 19.0; level of significance: p < 0.05.

Results:

A total of 75 patients with an average age of 74.4 ± 11.7 years and with a 62.7% males, were included. It was compared the group of patients with typical aIAB (T-aIAB) and with At-aIAB. The first one was associated with the existence of diabetes mellitus (p = 0.001), chronic kidney disease stage ≥ 3 (p = 0.036), atrioventricular block (p = 0.006) and a lower mean ventricular ejection fraction (p = 0.025); there were no differences regarding the prevalence of atrial fibrillation/flutter or stroke. Only diabetes was associated with the risk of T-aIAB (odds ratio: 6.4; p = 0.002; 95% confidence interval: 2.0-21.1).

Conclusions:

Diabetes mellitus is the only risk factor for an aIAB to be typical. Patients with T-aIAB and At-aIAB have a similar prevalence of atrial fibrillation and stroke, so they must follow the same clinical management.

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