This 66-year-old man received a Lumax 740 VR-T DX defibrillator, connected to a single VDD lead with an atrial sending dipole, implanted for primary prevention in the context of dilated cardiomyopathy and depressed left ventricular ejection fraction. He was followed by telecardiology and an alert message was transmitted.
Telemedicine report
Alert message (yellow status) for episode of classified atrial monitoring.
As in a standard dual chamber defibrillator, four channels are displayed: the markers with time intervals, the shock delivery channels (Far Field, FF), the atrial sensing channel, and the right ventricular sensing channel. The EGM show a rapid, irregular rhythm correctly detected at the ventricular level and a very rapid and irregular rhythm, consistent with conducted atrial fibrillation.
This kind of device is specific to Biotronik Inc., allowing the analysis of atrial activation by a single lead VDD system. The Lumax VR-T DX is connected to a dedicated defibrillation lead, equipped with a floating atrial dipole, which senses the atrial signals. The atrial information is the same as that provided by a standard dual chamber defibrillator. The management of atrial fibrillation can be optimized by combining telecardiology and the entire atrial diagnostics. In this patient, the analysis of the atrial EGM ascertained the diagnosis, allowing an adaptation of the management and therapy. The atrial information can also be used to discriminate the arrhythmias. The single or dual chamber SMART algorithms are available and can be used according to the physician’s choice, which hinges on the quality of atrial sensing. The initial signals are amplified, though sensing by a floating dipole can be imperfect, as it was in this patient. While dual chamber might be slightly superior to single chamber discrimination when atrial sensing is flawless, it probably should be avoided when sensing is of fair or low quality. In this patient, we chose the programming of single chamber discrimination, since the atrial information had allowed a distinction of the characteristics of the arrhythmia (paroxysmal versus persistent), as well as an evaluation of the efficacy of the antiarrhythmic treatment that had been implemented.