Atrial fibrillation is a common arrhythmia which requires electrical cardioversion in many patients in order to regain sinus rhythm. In a previous retrospective study a complication of acute renal failure was found in 17% of the patients after cardioversion.(The incidence and prognosis of renal dysfunction following cardioversion of atrial fibrillation. Helman Y,...Gilon D et al:Cardiology 2013;124(3);184-9.) Another complication previously described after cardioversion is pulmonary edema.

In this prospective study the investigators aim to evaluate the risk of acute renal failure post cardioversion. In addition the investigators would like to evaluate hemodynamic changes, fluid balance and sodium levels in patients post cardioversion as a potential mechanism for both acute renal failure and pulmonary edema post cardioversion. In order to assess hemodynamic changes the investigators will use a non-invasive FDA approved device called NICaS (Non-Invasive Cardiac System). This system calculates cardiac output, cardiac index and peripheral vascular resistance in a non-invasive, fast and accurate way.

Inclusion Criteria:

• All patients with new onset atrial fibrillation

Exclusion Criteria:

• Pregnant

All patients with new onset atrial fibrillation. Meaning less than three days.