ECG challenge: Intermittent wide QRS complexes in heterotaxy syndrome.

We report wide QRS complexes appearing in conjunction with prolonged R-R intervals in a 5- year old patient with situs ambiguous and mirror image dextrocardia, who had undergone ASD and VSD closure at of the age of one. We present differential diagnoses of intermittent spontaneous QRS widening and refer to ECG lead positioning in mirror image dextrocardia patients.