1. Questionnaire for supraventricular tachycardia: About history and targeted diagnosis of supraventricular tachycardia
2. Extended Signal-averaged ECG for detailed P-Wave analysis and to calculate a virtual atrial electrocardiogram (ECG)

1. Questionnaire Patient questionnaires on supraventricular tachycardia including atrial fibrillation often refer to the symptoms of the cardiac arrhythmia and the resulting limitations in everyday life. The evaluation of these questionnaires only allows a rough differentiation between the various cardiac arrhythmias. Nevertheless, it is known that supraventricular tachycardias are influenced by the sympathetic and parasympathetic nervous system. For example, tachyarrhythmias can begin or be terminated with a reentry circuit through the atrioventricular (AV) node by Valsalva manoeuvres or some other change in tone of the nervus vagus. For atrioventricular reentrytachycardia (AVNRT) in particular, an increased probability of occurrence in poststress phases has been described, as well as an association with certain behaviours such as positional changes, but also alcohol and drug consumption. To date, there is no systematic questionnaire on the specific triggering and terminating components. All patients referred for ablation of a supraventricular arrhythmia and potentially included in this project will receive a detailed history of the triggering and terminating factors using a structured questionnaire, as well as two validated supraventricular tachycardia questionnaires (5Q-3L and ASTA) to classify the results of our questionnaire.
2. Extended ECG A high-resolution and signal-averaged ECG is recorded with a significantly higher resolution than a 12-lead ECG over a period of several minutes. Additional electrode positions are also used in the vicinity of the examined structure, e.g. the left atrium. The signal from several recorded heartbeats is then averaged. This preserves repetitive smallest atrial excitation patterns and changes. In this way, it is possible to find indications of cardiac arrhythmias like atrial fibrillation in the signal-averaged ECG, which were not detectable in a 12-lead ECG.

Inclusion Criteria:

• Scheduled for ablation of a supraventricular tachycardia (atrial fibrillation, typical atrial flutter, AV nodal reentry tachycardia, accessory pathway)
• majority

Exclusion Criteria:

• Unstable patient with need for intensive medical care
• Lack of language skills or limited cognitive abilities that prevent a differentiated anamnesis and information.

Exclusion criteria for study section Questionnaire:

- Competing clinically present arrhythmias, including relevant supra- and ventricular extrasystole (>5%/die).

Exclusion criteria for study section Extended high-resolution ECG:

• Previous electrophysiological ablation at the same site for atrial fibrillation.
• Relevant supra- and ventricular extrasystole (>5%/die).
• Other clinically present arrhythmias are not excluded if they can be sequentially triggered and ablated (e.g. atrial fibrillation and atrial flutter). Since separate detection is possible with the high-resolution ECG.
• Implanted active electrical device (e.g. pacemaker, defibrillator, deep brain pacemaker)
• Allergy to measuring electrodes

Cohort for study section Questionnaire: 1000 evaluable questionnaires are targeted. Every suitable potential respondent will be invited and interviewed during the data collection period. After 400 subjects in the questionnaire section, an interim evaluation will be carried out.

Cohort for study section extended high-resolution ECG: In a feasibility study, signal-enhanced ECGs will be recorded in a subgroup of cohort before, during and after ablation with the aim of non-invasive ECG diagnostics. There are no published empirical values for this and 250 subjects will be notified. After 100 subjects in the high-resolution ECG section, an interim evaluation will be carried out.

Data can be shared on reasonable request after data is already published