Another case has been reported about loss of atrial pacing with possible atrial mode switch due to atrial oversensing
in a patient with atrial arrhythmias .
(Figure-1B) During interrogation of the device, there was p-wave oversensing during sinus tachycardia by the ICD lead.
As the tip of the lead is pulled back towards the pocket according to its position, it may produce failure to pace, diaphragmatic contraction by phrenic nerve stimulation, pectoral muscle, or brachial plexus stimulation resulting in rhythmic arm twitching and may wrap around the pulse generator.6 In our patient, there was oversensing and failure to pace.
It was essential that the devices were programmed appropriately to avoid far-field R-wave oversensing
and atrial undersensing to ensure a high sensitivity and specificity for AF detection.
In particular, arrhythmia episodes or oversensing that have led to delivered or aborted ICD therapies can be analyzed using telemonitoring and the opportune counter-measures considered.
An episode of ventricular tachycardia (VT) was documented followed by VF detection, a ventricular oversensing, likely due to power line interference, which appeared from the EGM.
It is possible to observe rapid pacing due to atrial oversensing as the patient approaches an electromagnetic field, followed by a period of ventricular oversensing (inhibition or mode reversion) as the field becomes stronger.
Most interference was oversensing and occurred when the phone was placed directly over the implanted device.
Arrhythmias on surface ECG can be induced by undersensing, oversensing
or failure to capture (Fig.
Of the almost 2,000 arrhythmias identified and recorded by the ICD devices in this study, 8% were classified as oversensing
, 4% were sinus tachycardias, 18% were supraventricular arrhythmias, and 70% were ventricular arrhythmias.
In this case report, we describe a patient with an LVAD-ICD interaction that resulted in ventricular oversensing
and subsequent inhibition of pacing.
EMI is defined as oversensing
of extraneous signals that adversely affect the functioning of cardiac implantable electronic devices [2,3].