A method, including, receiving a first group ofelectrocardiograph (ECG) signals derived from a singleheartbeat and generated at a respective plurality ofelectrodes on a catheter in a heart of a subject,formulating a template relating times of annotations of thefirst group of the ECG signals, and assigning the templatean index. The method further includes receiving a secondgroup of ECG signals derived from a subsequent singleheartbeat and generated at the electrodes, calculating timesof annotations of the second group, formulating a comparisonbetween the template and the times of annotations of thesecond group, and, when the comparison indicates that thetimes of annotations of the second group correspond to thetemplate, assigning the index to the second group of ECGsignals, and presenting graphically on a display anoccurrence of the template relative to a timelinerepresenting heartbeats from the heart.
