text: Electrocardiographic monitoring can be used to identify the changes in QRS morphology such as alternating bundle branch block in the presence of atrioventricular conduction abnormalities. Also,Treadmill exercise stress testing may be diagnostic to differentiate that 2:1 atrioventricular block is Mobitz type I or II in some cases or identify the presence of infranodal disease. In addition, EPS may be helpful to determine the  anatomic site of block in mobitz type 2 atrioventricular block including atrioventricular node, intra-His, or infra-His. Worsening atrioventricular  block  with  isoproterenol and atropine may be suggestive of infranodal  block. However, improvement of atrioventricular conduction  with carotid  sinus  massage  may  be  observed in patients with infranodal atrioventricular block.
option_0: Second degree AV block other diagnostic studies
option_1: Third degree AV block other diagnostic studies
option_2: First degree AV block other diagnostic studies
option_3: Junctional tachycardia other diagnostic studies
option_4: Atrioventricular block other diagnostic studies
option_5: Ventricular tachycardia other disgnostic tests
option_6: Wide complex tachycardia risk factors
option_7: Pulseless ventricular tachycardia other diagnostic studies