Cardiac Ablation Dosing
A method and apparatus for applying energy to a target path on a tissue surface includes moving a proximal end of an energy source in a first direction by a first distance. During a first portion of the first distance, the source is in a non-energized mode. During a second portion of the first distance, the source in an energized mode. The proximal end is moved in a second direction along the path opposite the first direction and by a distance less than the first distance. During a first portion of the second direction, the source in a non-energized mode. During a second portion of the second direction, the source in an energized mode. The method compensates for a hysteresis between movement of a distal tip of the energy source and the proximal end.
1 . An apparatus for forming a lesion in tissue along a desired ablation path, said apparatus comprising:
a movable source of energy having a distal end for applying energy to said tissue opposing said distal end and having a proximal end with an initiation of movement of said distal end delayed from an initiation of movement of said proximal end by a variable amount of discrepancy less than a maximum discrepancy,
said distal end guided for movement along said target path in response to movement of said proximal end;
a controller for operating movement of said energy source and switching said energy source between an energized mode and a non-energized mode, said controller adapted to operate said energy source as follows:
to move said proximal end in a first direction by a first distance;
during a first portion of said first distance, to operate said source in a non-energized mode;
during a second portion of said first distance, to operate said source in an energized mode;
to moving said proximal end in a second direction along said path opposite said first direction and by a distance less than said first distance;
during a first portion of said second direction, to operate said source in a non-energized mode;
during a second portion of said second direction, to operate said source in an energized mode.
2 . An apparatus according to claim 1 wherein said controller is further adapted for repeating sequential ones of said first and second directions along a length of said path.
3 . An apparatus according to claim 1 wherein said first portion of said first distance is not less than said maximum discrepancy.
4 . An apparatus according to claim 3 wherein said first portion of said second distance is not less than said maximum discrepancy.
5 . An apparatus according to claim 4 wherein said first portion of said first distance is greater than said first portion of said second distance.
6 . An apparatus according to claim 5 wherein said second portions of said first and second distances are substantially equal.
7 . An apparatus according to claim 6 wherein said first portion of said first distance is at least twice said first portion of said second distance.
8 . An apparatus according to claim 1 wherein said energy source is an optical fiber with said proximal end connected to a laser power source.
9 . An apparatus according to claim 1 wherein said energy source is a source of radiofrequency energy.
10 . An apparatus according to claim 1 wherein said energy source is a source of thermal energy.
11 . An apparatus according to claim 1 wherein said energy source is a cryogenic.
12 . An apparatus according to claim 1 wherein said energy source is ultrasound.
13 . A method for applying energy to a target path on a tissue surface using a movable source of energy having a distal end for applying energy to said tissue opposing said distal end and having a proximal end with an initiation of movement of said distal end delayed from an initiation of movement of said proximal end by a variable amount of discrepancy less than a maximum discrepancy, said distal end guided for movement along said target path in response to movement of said proximal end, said method comprising:
moving said proximal end in a first direction by a first distance;
during a first portion of said first distance, said source in a non-energized mode;
during a second portion of said first distance, said source in an energized mode;
moving said proximal end in a second direction along said path opposite said first direction and by a distance less than said first distance;
during a first portion of said second direction, said source in a non-energized mode;
during a second portion of said second direction, said source in an energized mode.
14 . A method according to claim 13 further comprising repeating sequential ones of said first and second directions along a length of said path.
15 . A method according to claim 14 wherein said first portion of said first distance is not less than said maximum discrepancy.
16 . A method according to claim 15 wherein said first portion of said second distance is not less than said maximum discrepancy.
17 . A method according to claim 16 wherein said first portion of said first distance is greater than said first portion of said second distance.
18 . A method according to claim 17 wherein said second portions of said first and second distances are substantially equal.
19 . A method according to claim 18 wherein said first portion of said first distance is at least twice said first portion of said second distance.
20 . A method according to claim 13 wherein said energy source is an optical fiber with said proximal end connected to a laser power source.
21 . A method according to claim 13 wherein said energy source is a source of radiofrequency energy.
22 . A method according to claim 13 wherein said energy source is a source of thermal energy.
23 . A method according to claim 13 wherein said energy source is a cryogenic.
24 . A method according to claim 13 wherein said energy source is ultrasound.