OPTIMUM LEAD POSITIONING FOR RECORDING BIPOLAR ATRIAL ELECTROCARDIOGRAMS DURING SINUS RHYTHM AND ATRIAL-FIBRILLATION

Background: To date, Holter monitoring has been predominantly utilized in the investigation and monitoring of ventricular arrhythmias and my ocardial ischemia. Whether currently employed lead configurations are optimal for recording atrial electrocardiograms (ECGs) is unknown. Hyp othesis: This study was undertaken to determine which conventional and novel lend configurations an optimal for recording atrial electrical activity during sinus rhythm and atrial fibrillation. Methods: Recordi ngs were performed on eight healthy volunteers in sinus rhythm and fou r patients in atrial fibrillation. Each subject had 10 ECGs of three b ipolar and three augmented unipolar leads recorded during supine rest, while rising to upright, and during standing rest, yielding a total o f 60 leads (30 bipolar leads). Each tracing was inspected by two obser vers, and parameters such as P-wave amplitude and duration, whether th e P-wave onset was clearly seen, atrial fibrillatory-wave amplitude, a nd amplitude of noise during standing were scored. Results: Leads reco rding inferiorly and leftward orientated bipoles provided the best reg istration of sinus P waves. The P-wave amplitude in the standard bipol ar C5 lead (0.12 +/- 0.02 mV) was, however, inferior to others such as recordings between C1 and C6 positions (P-wave amplitude 0.16 +/- 0.0 2 mV) or from below the right clavicle to the left upper quadrant of t he abdomen (0.16 +/- 0.01 mV). Optimal recording of fibrillatory waves was from different leads, such as a bipole from below the left clavic le to a low C1 position (fibrillatory wave amplitude 0.27 +/- 0.03 mV) . Conclusion: When Holter recordings are performed for the investigati on of atrial arrhythmias. nonstandard lead configurations provide supe rior recording of atrial electrical activity. We advocate the use of e lectrodes positioned from C1 to C6, from below the left clavicle to a low C1 position, and a vertically orientated lead fr om the manubium t o the twelfth vertebra or the xiphisternum.