Arrhythmias are widespread among the global population. Although they can occur in healthy hearts, they are often the manifestation of a hereditary or acquired heart muscle disease, and may be the cause or, more often than not, the consequence.

In recent decades, with advances in medical knowledge and technology, non-pharmacological therapies for arrhythmias have become increasingly popular. These fall into two broad categories: therapies aimed at electrostimulation and those aimed at ablation of arrhythmias.

The selection of patients eligible for these procedures is essential for the effectiveness of the therapy, the reduction of complications and the optimisation of resources.

Not all patients, even those selected according to guidelines, respond equally to the chosen therapy. Other patients, due to their clinical/ECG characteristics, do not have clear indications and remain in a borderline area where the class of evidence and/or recommendation of the guidelines is less stringent. Still others develop recurrences or complications during follow-up that require further intervention.

In this context, it is essential in the study of these patients not only to use standard instrumental examinations, such as echocardiograms, Holter ECGs and stress tests (simple and cardiopulmonary), but also and above all to use advanced imaging methods (STE, 3D echo, MRI, CT, PET-CT) and remote monitoring tools that integrate diagnostic algorithms managed by artificial intelligence.

In light of these considerations, our project consists of conducting an observational study that includes all patients with arrhythmias who are candidates for electrostimulation and/or ablation procedures at the Arrhythmology Unit and/or followed up at the Arrhythmology Clinic of our Polyclinic, in order to assess the clinical and/or imaging characteristics associated with a worse prognosis in this population, in terms of response to therapy and development of complications. Our main aim is to identify, within the above-mentioned population, the subgroups of responder patients versus non-responder patients, i.e. those with a worse prognosis , who deserve greater attention and more frequent follow-up.

Inclusion Criteria:

• Only patients aged > 18 years with a history of arrhythmia warranting non-pharmacological treatment according to the guidelines will be selected.
• Collection of informed consent for the prospective cohort.
• For the retrospective cohort, the Promoter has carried out a Data Protection Impact Assessment (DPIA), which ascertained the adequacy of the technical and organisational measures adopted to ensure the protection of the fundamental rights and freedoms of data subjects, in accordance with Article 89 of Regulation (EU) 2016/679 and the guidelines of the Data Protection Authority. Data processing will be limited to the purposes of the study and conducted in accordance with the principles of minimisation, pseudonymisation and security, in compliance with the guarantees defined by the Data Protection Authority.

Exclusion Criteria:

• Patients who, upon initial assessment at our centre, do not present arrhythmias that would indicate non-pharmacological treatment.
• Patients for whom it is not possible to obtain adequate medical history and/or follow-up through medical examination or telephone consultation.
• Refusal to give informed consent to participate in the study.

Patients who are candidates for electrophysiological and/or electrostimulation procedures