investigation revealed two different arrhythmias , both induced by the pacemaker : ( 1 ) a tachycardia in which the dual-chamber pacemaker system provided the antegrade limb and the av node provided the retrograde limb and ( 2 ) a triggered , ventricularly paced tachycardia caused by the pacemaker sensing atrial fibrillation waves .
C0003811
arrhythmias
C0004238
atrial