| Abstract: | Background: To date, Holter monitoring has been predominantly utilized in the investigation and monitoring of ventricular arrhythmias and myocardial ischemia. Whether currently employed lead configurations are optimal for recording atrial electrocardiograms (ECGs) is unknown. Hypothesis: This study was undertaken to determine which conventional and novel lead configurations are optimal for recording atrial electrical activity during sinus rhythm and atrial fibrillation. Methods: Recordings were performed on eight healthy volunteers in sinus rhythm and four patients in atrial fibrillation. Each subject had 10 ECGs of three bipolar and three augmented unipolar leads recorded during supine rest, while rising to upright, and during standing rest, yielding a total of 60 leads (30 bipolar leads). Each tracing was inspected by two observers, and parameters such as P-wave amplitude and duration, whether the P-wave onset was clearly seen, atrial fibrillatory-wave amplitude, and amplitude of noise during standing were scored. Results: Leads recording interiorly and leftward orientated bipoles provided the best registration of sinus P waves. The Pwave amplitude in the standard bipolar C5 lead (0.12 d? 0.02 mV) was, however, inferior to others such as recordings between Cl and C6 positions (P-wave amplitude 0.16 d? 0.02 mV) or from below the right clavicle to the left upper quadrant of the abdomen (0.16 d? 0.01 mV). Optimal recording of fibrillatory waves was from different leads, such as a bipole from below the left clavicle to a low C1 position (fibrillatory wave amplitude 0.27 d? 0.03 mV). Conclusion: When Holter recordings are performed for the investigation of atrial arrhythmias, nonstandard lead configurations provide superior recording of atrial electrical activity. We advocate the use of electrodes positioned from C1 to C6, from below the left clavicle to a low C1 position, and a vertically orientated lead from the manubium to the twelfth vertebra or the xiphisternum. |
