1. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Lead I of the surface electrocardiogram as recorded (top panel), with further amplification (middle panel) and with further amplification and filtration (bottom panel). Figure Legend:

2. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Correlation between PTa and atrial paced cycle length (PP) in 20 patients (n = 103 points); rho = 0.76, p < 0.001, slope = 0.24, intercept = 243 ms. Figure Legend:

3. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Correlation between Ta and atrial paced cycle length (PP) in 20 patients (n = 103 points); rho = 0.62, p < 0.001, slope = 0.24, intercept = 124 ms. Figure Legend:

4. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Correlation between P and atrial paced cycle length (PP) in 20 patients (n = 103 points); rho = 0, p = NS. Figure Legend:

5. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Effect of intravenous propranolol (0.1 mg/kg) on the atrial surface electrocardiogram. Before propranolol: P = 106 ms, Ta = 289 ms. On propranolol: P = 102 ms, Ta = 319 ms. C = corrected. Figure Legend:

6. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Effect of propranolol, atropine, disopyramide and flecainide on the atrial cycle length (PP). Figure Legend:

7. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Effect of propranolol, atropine, disopyramide and flecainide on the atrial surface electrocardiographic intervals, PTa, P and Ta. Figure Legend:

8. Date of download: 7/7/2016 Copyright © The American College of Cardiology. All rights reserved. From: Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram J Am Coll Cardiol. 1999;33(2):358-365. doi:10.1016/S0735-1097(98)00580-4 Effect of propranolol, atropine, disopyramide and flecainide on the PTa interval corrected for rate using the linear regression equation (top panel) and Bazett’s hyperbolic formula adapted to the atrium (bottom panel). Figure Legend: