Abstract
Background: Interatrial block (IAB: P wave ≥ 110 ms) is a strong correlate of left atrial (LA) enlargement and an important predictor of supraventricular tachyarrhythmias, notably atrial fibrillation and flutter. It is surprising that, despite its association with arrhythmias and its effects on the electromechanical properties of the left atrium, there is widespread neglect of this common abnormality.
Hypothesis: The study was undertaken to investigate the prevalence of IAB in a general hospital population.
Methods: We prospectively evaluated the electrocardiograms of 1,000 consecutive adult patients, analyzed for P‐wave duration.
Results: Our results showed a very high prevalence of IAB (41.1% of patients in sinus rhythm and 32.8% of all patients). As expected, it was more common in patients aged > 60 years.
Conclusions: Given this unusually high prevalence of IAB in hospital patients and its ominous portents (LA enlargement, thrombosis and embolism, arrhythmias), physicians should be aware of its frequency and computer software should be programmed to recognize it.
Keywords: electrocardiography, interatrial block, P wave
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