This study investigates how many atrial paced beats are needed to speed up the tachycardia cycle length to match the paced cycle length. Tachycardia is a condition where the heart beats faster than normal. By assessing this, researchers aim to identify where the atrial tachycardias (ATs) originate based on the results of ablation, a procedure used to treat abnormal heart rhythms.

Participants will undergo procedures to measure the number of atrial paced beats required to adjust the heart's rhythm. Ablation results will help in understanding the source of ATs, which are abnormal rapid heartbeats starting from the atria, the upper chambers of the heart.

• Who can participate: Eligibility criteria include age and key factors, which are not specified in the provided information.
• Study details: Participants will have their heart rhythms adjusted through atrial pacing. The study will use ablation results to determine the origin of atrial tachycardias. If applicable, a placebo, an inactive substance that looks like the investigational medicine/vaccine but does not contain any medicine, may be used.