PERIODIC SAMPLING OF CARDIAC SIGNALS USING AN IMPLANTABLE MONITORING DEVICE

In a method of diagnosing an atrial fibrillation or atrial flutter condition, a monitoring device implanted in a subject acquires strips of a subcutaneous ECG signal of a predetermined length. The strips are acquired at regular, periodic intervals, and the timing of when the strips are acquired is not triggered by analysis of the subcutaneous ECG signal by the monitoring device. The acquired subcutaneous ECG strips are stored in memory of the implanted monitoring device, and transmitted from the implanted monitoring device for receipt by an external analysis system. In the external analysis system, the received subcutaneous ECG strips are processed to generate information for an assessment of an atrial fibrillation or atrial flutter burden for the subject.