Intermittent advanced atrial depolarization abnormality?

Abnormal atrial depolarization, characterized by P waves > or =110 ms on the electrocardiogram, can manifest as partial or advanced interatrial block (IAB). Advanced IAB, denoted by biphasic P waves in leads II, II and aVF, is considered to confer increased severity in interatrial conduction delay, and is now perceived to be a result of continued deterioration in interatrial impulse propagation between the atria. While progression from partial to advanced IAB has been described, the converse, resolution of advanced IAB, which has often been touted as 'complete block' to its partial, 'incomplete' type, i.e. the occurrence of intermittent advanced IAB, has escaped observations so far. We present the first known report of such a scenario.