"1" To examine whether right ventricular pacing has an impact on tricuspid regurgitation grade that is related to pacing rather than to valve closure interference by the electrode.

"1" Traditionally, tricuspid regurgitation in the presence of pacemaker is attributed to the physical interference of the valve closure by the electrode.

"2" Right ventricular pacing may be associated with dyssynchrony in contraction of the right ventricular wall (i.e. septum and free wall.

"3" The tricuspid sub-valvar apparatus is anchored to the septum and free wall, thus may be sensitive to dyssynchrony in those wals contraction.

"4" The study hypothesis is that the dyssynchrony in right ventricular contraction, induced by pacing, may increase tricuspid regurgitation grade and that this is a mechanism is independent of the mechanical effect of the electrode on the valve closure.

Inclusion Criteria:

• Age >18 years
• Permanent pacemaker

Exclusion Criteria:

• Epicardial pacing
• Left ventricular dysfunction
• Organic tricuspid regurgitation
• Bi-ventricular pacemaker
• Atrial fibrillation
• Complete pacemaker dependence

Outpatients, clinically stable, with a permanent pacemaker and who are not pacemaker dependent.