AI-powered ECG Analysis Using Willem™ Software in High-risk Cardiac Patients (WILLEM)

Inclusion Criteria: * Patient presenting relevant cardiac arrhythmias and cardiac patterns (including supraventricular tachycardias, abnormal ECG patterns, ventricular tachycardias, ventricular fibrillation, pulseless electrical activity or asystole among others) that have been recorded with at least one short-term ECG medical device according to guidelines with ≥1 signal-channel. * Patient with suspected or diagnosed acute/chronic cardiac diseases (including patients with heart failure, patients with history of cardiac arrhythmias, patients with probable coronary artery diseases, patients with cardiomyopathies, patients with pacemakers or implantable cardioverter-defibrillators (ICD), patients with indication of pacemaker or ICD in current or short-term phase, patients participating in other interventional clinical investigation, patients with hemodynamic instability or acute coronary syndromes, pregnant patients, patients with cancer and chemotherapy, patients with life-expectancy lower than 24 months, patients with in or out-of-hospital cardiac arrest with ventricular fibrillation as first documented rhythm). * At least one ECG tracing that can be exported in raw data. * Signed informed consent. Patients unable to consent, it will be requested to an authorized relative. Exclusion Criteria: * Unwillingness or inability to sign study written informed consent. * Unavailable or suboptimal quality of the electrocardiographic signal in raw data.