It is suggested that P-wave terminal force (Ptf), a product of the amplitude (PAM) and the duration (PT) of the terminal phase of P-wave in lead V1, shows early delay in left atrial conduction, observed earlier that the dilatation of left atrium.

The aim is to follow PT, PAM and Ptf changes during 5-year follow-up (5FU) and examine the relation of these changes to the number of AF episodes requiring hospitalisation (HOSP) for restoration of sinus rhythm (RSR).

Background. It is suggested that P-wave terminal force (Ptf), a product of the amplitude (PAM) and the duration (PT) of the terminal phase of P-wave in lead V1, shows early delay in left atrial conduction, observed earlier that the dilatation of left atrium.

Aim. We aim to follow PT, PAM and Ptf changes during 5-year follow-up (5FU) and examine the relation of these changes to the number of AF episodes requiring hospitalisation (HOSP) for restoration of sinus rhythm (RSR).

We hypothesise that, in patients with atrial fibrillation (AF):

1. the index parameters (PT, PAM, Ptf), characterising left atrial repolarization, correlates the number of future hospitalisations (HOSP) aimed for restoration of sinus rhythm (RSR) in 5-year follow-up (5FU)
2. in 5FU the number of HOSP aimed for RSR correlates with the progression of left atrium electrical remodelling, expressed as PAM5,PT5, Ptf5 at 5FU.

Inclusion Criteria:

• documented atrial fibrillation at admission
• successful restoration of sinus rhythms documented in 12-leads ECG,
• follow-up => 5 years

Exclusion Criteria:

• arrhythmia other than atrial fibrillation at admission,
• unsuccessful restoration of sinus rhythms,
• successful restoration of sinus rhythms but missing 12-leads ECG recording,
• previous ablation/operation within left atrium,
• follow-up < 5 years

Patients with atrial fibrillation admitted between 1.1.2001 and 30.12.2012 for elective and emergency hospitalization aimed for restoration of sinus rhythms with DC cardioversion.