TY - JOUR T1 - ECG phenomena: alternating QRS morphologies JF - Heart JO - Heart SP - 596 LP - 596 DO - 10.1136/heartjnl-2013-305290 VL - 100 IS - 7 AU - Christian Paech AU - Nicole Pfeil AU - Roman Antonin Gebauer Y1 - 2014/04/01 UR - http://heart.bmj.com/content/100/7/596.abstract N2 - A male newborn was referred to our centre for surgery of a hypoplastic left heart syndrome with atresia of the aortic and mitral valve. He received modified Norwood I procedure with patch reconstruction of the aortic arch and pulmonary artery bifurcation as well as implantation of a conduit between RV and pulmonary artery. Postoperative echocardiography showed good ventricular function and no signs of ventricular dyssynchrony. What is the cause of the two different QRS morphologies? (figure 1) Pre-excitation Intermittent bundle branch block (BBB) Artefact Twin atrioventricular nodes Accelerated ventricular rhythm Figure 1 ECG trace. From question on page XXX Answer:D The correct … ER -