Implantable Loop Recorder - for Arrhythmias

The implantable loop recorder (ILR) is a subcutaneous, single-lead, electrocardiographic (ECG) monitoring device used for diagnosis in patients with recurrent unexplained episodes of palpitations or syncope, for long-term monitoring in patients at risk for or with documented atrial fibrillation (AF), and for risk stratification in patients who have sustained a myocardial infarction (MI) and those who have certain genetic disorders.

The device is capable of storing ECG data automatically in response to a significant bradyarrhythmia or tachyarrhythmia or in response to patient activation. It is particularly useful either when symptoms are infrequent (and thus not amenable to diagnosis using short-term external ECG recording techniques).

The device is typically implanted under the skin, in the left side of chest.

Indications

• unexplained, repetead syncope (loss of conciousness)
• palpitations
• risk stratification post myocardial infarction
• patients with or at risk for atrial fibrillation
• dizziness

Contraindications

• The presence of an active infection or a bleeding diathesis may preclude implantation.
• As I pointed above, altough long term monitoring is useful for diagnosis when symptoms are rare, there are also some disadvantages:
• the need for a minor surgical procedure
• the difficulty of always being able to differentiate arrythmia’s orogin ( supraventricular from ventricular arrhythmias)
• malfunction may exhaust the memory of the ILR
• the cost of the device – the ILR has a high initial cost; however, it may actually be more cost-effective than a strategy incorporating multiple nondiagnostic investigations. Although symptom-rhythm correlation can be obtained in the vast majority of patients, about 25 % of all patients remain without definite diagnosis despite the use of ILR. In addition the need for proper patient selection is high.