Non-invasive assessment of atrial electrophysiology in AF-influence of posture change

The authors sought to non-invasively defect changes in atrial fibrillation rhythm during autonomic provocative maneuvers. Digital Holter from 23 patients with chronic AF before and after active postural change were subjected to routine editing, and then underwent QRS and T wave subtraction, leaving pure atrial fibrillatory records. Spectral analysis by autoregressive method was performed on this record. The total spectral power, and that in the 4-10 Hz range was calculated and compared before and after posture change. Analysable data was acquired front 17 patients. Postural change caused a fall in spectral power (total power: from 19442 to 8154, 4-10 Hz power: 4031 to 1764), and a concentration of the power in the 4-10 Hz range. Increased sympathetic tone due to active postural change causes a fall in total spectral power and a concentration of that power in the AF frequency band. Atrial electrophysiology during AF can be studied noninvasively.