Case report
A 70-years-old man with a ischemic cardiomyopathy underwent ICD implant
at an outside institution for primary prevention of sudden cardiac death
three years ago. The ICD was a Medtronic Maximo II VR with a dual-coil
VVI ICD lead. Two weeks ago the patient experienced a shock. The
electrocardiography showed NSR (Figure 1). Device interrogation
demonstrated that the stored intracardiac electrograms (EGMs) of the
events are shown in Figures 2-3. The analysis of the episode revealed a
sudden change to very rapid and irregular myocardial activity with EGM
alternans that reach VF zone and a shock is delivered that restores
sinus rhythm (Figure 3 ).Chest X-ray and fluoroscopy showed the active
ICD lead was in the coronary sinus (Figure 4). There was no ventricular
capture with pacing from ICD (Figure 5).This could only be explained by
sensing of atrial signal during an acute AF in the ICD lead, probably
due to inappropriate lead implantation to the coronary sinus during the
first procedure. The patient has been treated with new single coil
active ICD lead implantation to the right ventricule and old ICD
electrode left in place (Figure 6).