Arrhythmias of the atria of the heart are a common comorbidity in patients with cardiac rhythm management devices, such as pacemakers and implantable cardioverter/defibrillators (ICD). External electrical cardioversion is an established method to achieve rhythm control (restore normal sinus rhythm) in patients with atrial arrhythmia. Little data on safety and efficacy of external electrical cardioversion in patients with cardiac rhythm management devices exists. Thus, available data on the safety of external electrical cardioversion in cardiac rhythm management patients lacks statistical power to accurately reflect the true hazard of external electrical cardioversion in patients with cardiac rhythm management devices.

The aim is to systematically include and follow all patients with cardiac rhythm management devices presenting for external electrical cardioversion, to analyse the effects of external electrical cardioversion on leads and devices.

Introduction Atrial arrhythmias are a common comorbidity in patients with cardiac rhythm management (CRM) devices, such as pacemakers and ICD. External electrical cardioversion is an established method to achieve rhythm control in patients with atrial arrhythmia. A paucity of data on safety and efficacy of external electrical cardioversion in patients with cardiac rhythm management devices exists. Most publications are of older date and predominantly case reports or case collections. Few prospective studies with a population of cardiac rhythm management patients after external electrical cardioversion have been published in recent years.

Thus, available data on the safety of external electrical cardioversion in cardiac rhythm management patients lacks statistical power to accurately reflect the true hazard of external electrical cardioversion in patients with cardiac rhythm management devices.

Rationale Electrocardioversion in Propofol sedation for atrial or ventricular tachyarrhythmia is an established therapy. It is routinely used for patients with cardiac rhythm management devices and the risk of device and lead affectation is deemed to be low. This assumption is currently not supported by substantial and current scientific data, mostly relying on older reports. No large, prospective trials with a population of patients with modern cardiac rhythm management devices exists.

Aim of the study The aim is to systematically include and follow all patients with cardiac rhythm management devices presenting for external electrical cardioversion, to analyse the effects of external electrical cardioversion on leads and devices. Thereby, providing reliable evidence and detecting possible SAE with a low incidence. Furthermore, to gather information on efficacy and recurrence rate in this population, to examine the value of external electrical cardioversion for rhythm control in these patients.

Inclusion Criteria:

• Age ≥ 18 years
• Informed, written consent
• Atrial or ventricular arrhythmia with indication for CV
• Status post CRM implantation, including CRT-D

Exclusion Criteria:

• Age < 18 years
• Patients under guardianship or with mental disorders / disabilities
• lead implantation < 4 weeks prior to CV
• contraindications for eCV or transoesophageal echocardiographie (TOE)

All patients with implanted cardiac rhythm devices (pacemakers, ICD and CRT)