Echocardiography examination
All patients had well-controlled heart rate and underwent transthoracic
and transoesophageal echocardiography prior to the ablation using a
Vivid E9 ultrasound system (GE Vingmed Ultrasound AS). The following
variables were prospectively measured during AF as an average of five
cardiac cycles and indexed to the body surface area: LA anteroposterior
diameter, RA and LA maximum and minimum length (long axis) and
planimetered area and volume. All measurements were performed by a
single experienced physician using well established criteria [3]. RA
and LA contractile and reservoir functions were analysed calculating the
following indices and expressed as percentage where appropriate: (1)
emptying fraction (EF), by dividing the difference between maximum and
minimum volume by maximum volume (2) stroke volume (SV), as the
difference between maximum and minimum volume (3) expansion index (EI),
by dividing the difference between maximum and minimum volume by minimum
volume. The right to left atrial ratio of all determined parameters was
then calculated and expressed as percentage. Moreover a biatarial volume
index expressed as the sum of the right and left atrial indexed maximum
and minimum volume and biatarial area index expressed as the sum of the
right and left atrial indexed maximum and minimum planimetered area were
calculated. Enlargement of the LA was defined with maximum indexed LA
volume >34ml/m2 whereas enlarged RA with
maximum indexed RA volume >25ml/m2 in men
and > 21ml/m2 in women. Left ventricular
hypertrophy (LVH) was defined on the basis of indexed ventricular mass
calculated by system software > 115g/m2in men and >95g/m2 in women [3].
Mitral (MR) and tricuspid (TR) regurgitation was assessed according to
guidelines [4].