Failure to recruit.

This study aims to determine the sensitivity and specificity of a Personal Heart Rhythm Monitor in the detection of prolonged paroxysmal atrial fibrillation (defined as lasting more than 12 hours) against pre-existing implantable devices, seen to be the 'gold-standard' for arrhythmia detection.

The Investigators aim to recruit 30 volunteers with implantable devices (either conventional pacemakers, with an atrial lead or implantable loop recorders, devices inserted under the skin to monitor the heart rhythm). They will be attending for their routine pacemaker checks in a number of clinics in Surrey.

Potential participants will have documented prolonged paroxysmal atrial fibrillation (PAF, an intermittent irregular heart rhythm which is known to predispose to stroke), lasting at least 12 hours, identified in the last month prior to the pacemaker check.

Willing patients will then be issued with a PHRM (Personal Heart Rhythm Monitor) device to make heart rhythm recordings for 3 months. They will do this twice-daily for 30 seconds for this period. At the end of the 3 month period patients will undergo a final pacing device check. Identification of prolonged PAF using the PHRM device will be compared to the implantable device.

Inclusion Criteria:

• Prolonged AF (defined as an episode at least 12 hours duration) in the last month whilst attending routine pacemaker check
• Pacing requirement < 25% during the last month

Exclusion Criteria:

• Lack of capacity
• Inability to use the Personal Heart Rhythm Monitor due to cognitive or physical impairment
• Commencement of new anti-arrhythmic drug since last pacemaker check