Comparison of the Performance of ICM and CIED in Detecting AF

Comparison of the Performance of Implantable Cardiac Monitors and Cardiac Implantable Electronic Devices in Detecting Atrial Fibrillation

The aim of this project is to study the performance of the two most commonly used Implantable Cardiac Monitors in detecting AF episodes and explore how the new connectivity can empower patients and improve patient care.

Atrial fibrillation (AF) is the most common abnormal heart rhythm disturbance, affecting 1-2 million people in the UK. The irregular heartbeat caused by AF can make the heart pump blood less efficiently. As a result, AF significantly increases the risk of having a stroke, heart failure and dementia. However, a significantly proportion of people have no symptoms, and they may be only found to be in AF after having a stroke. Therefore, diagnosis largely relies on accurate electrocardiogram (ECG) monitoring.

AF episodes can be unpredictable and easily missed unless continuous ECG monitoring is undertaken. Pacemakers can continuously record the heart's electrical activity and detect AF with a high degree of confidence. However, they are invasive and rely on electrical wires implanted inside the heart, and hence less suited to be used as primary monitoring devices. To overcome these difficulties, implantable cardiac monitors (ICM) have been designed to be placed under the skin.

The new generation of ICMs can now be injected under the skin. Moreover, they connect with the patient's smartphone and transmit recordings. Despite these significant improvements, their ability to reliably capture AF has never been tested against pacemakers.

The aim of this project is to study the performance of the two commonly used ICMs in detecting AF episodes and explore how the new connectivity can empower patients and improve patient care. The investigators plan to inject an ICM in 30 patients with AF and pre-existing pacemaker. After a period of 6 months, the investigators will compare how many episodes were detected in each device. With the information collected the investigators will try to understand the pitfalls in the current technology and develop strategies to improve it.

Accurate, minimally invasive long-term ECG monitor can have far reaching benefits for patients, both in routine clinical practice and research.

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation in the trial.
• Male or Female.
• Aged 18 years or above.
• History of paroxysmal and persistent AF.
• Dual-chamber pacemaker, Implantable cardioverter defibrillator (ICD) or cardiac resynchronisation therapy (CRT) device with a functioning atrial lead, able to record electrograms and remote monitoring.

Exclusion Criteria:

• Diagnosis of permanent AF.
• Contra-indications for implantable cardiac monitor.
• Unable to comply with the follow-up schedule.