To describe the clinical indications for Reveal XT in diagnosis and continuous monitoring of arrhythmia and to explore the clinical applications and outcome of arrhythmia monitoring on patient care.

Improving the diagnosis and management of cardiac rhythm disturbances remains a major challenge for physicians. Limitations of current cardiac arrhythmia monitoring using ECG, holters or event recorders are that these methods are non-continuous and/or automatic arrhythmia detection is often impossible. The Medtronic Reveal XT Insertable Cardiac Monitor is a programmable device which continuously monitors the patient's subcutaneous ECG and provides information regarding arrhythmia episodes, long term trending of AF burden, patient's activity and heart rate variability. The Reveal XT records cardiac information in response to patient activation and automatically detected arrhythmias thereby offering advantages over conventional tools for long-term arrhythmia monitoring with regard to compliance and recording time.

The clinical applications for Reveal XT are varied. Diagnostic, arrhythmia monitoring and arrhythmia management functions can be discriminated.

This study is a prospective, observational, multicenter international post-market study. The results of this study will describe the different patient groups for which the Reveal XT is being used for the diagnosis and monitoring of various cardiac arrhythmias. This study will also collect data regarding the clinical consequences of using the Reveal XT and the influence of Reveal XT data on clinical care pathways. The physician as well as the patient's satisfaction with the device will be evaluated. The study will be conducted in 60-100 centers primarily in Europe. It is expected that 800-1000 patients will be enrolled.

Inclusion Criteria:

• Patient implanted or scheduled for an implant with a Reveal XT Insertable Cardiac Monitor System for arrhythmia diagnosis or monitoring
• Patient must be willing to sign a Patient Data Release Form (or Informed Consent where applicable)

Exclusion Criteria:

• Enrollment outside a 30-day window from the planned/performed Reveal XT implant procedure (from 15 days pre-implant until 15 days post implant)
• Patient is implanted with a pacemaker, ICD, CRT-device or an implantable hemodynamic monitoring system
• Unwillingness or inability to cooperate or give written informed consent or, if the patient is a minor and the legal guardian refuses to give consent

Patients currently implanted with, or who will be implanted with a Reveal XT Insertable Cardiac Monitor for arrhythmia diagnosis or monitoring.