Right axis deviation.
Negative P waves in inferior leads (II, III and aVF) suggest low atrial rhythm.
ECG abnormalities that are reported to occur after percutaneous or surgical closure of the ASD
Frequent atrial premature contractions (APC).
Supraventricular tachycardia (SVT) attacks.
Varying degrees of atrioventricular (AV) blocks (rarely complete AV block).
Usually, the blocks are reported to disappear in a few weeks.
Sick sinus syndrome may be seen after closure of the sinus venosus type ASD.