Basket catheter with cloverleaf structure to provide predetermined lateral stiffness and axial strain

1 . A medical probe, comprising:

an expandable basket assembly configured to be coupled to a distal end of a tubular shaft, the basket assembly comprising:

a plurality of spines extending along a longitudinal axis from a proximal central proximal spine portion to a distal spine portion, the distal spine portion defining a cloverleaf structure disposed radially around the longitudinal axis, the cloverleaf structure defining a central cutout with a central area disposed about the longitudinal axis, the cloverleaf structure comprising a sinusoidal-like member extending from one spine to an adjacent spine in a direction around the longitudinal axis, the sinusoidal-like member meanders around:

(a) a first virtual circle having a first radius, the first virtual circle having its center located at a first distance to the longitudinal axis,

(b) a second virtual circle having a second radius, the second virtual circle having its center located at a second distance smaller than the first distance to the longitudinal axis, and

(c) a third virtual circle having a third radius approximately equal to the first radius, the third virtual circle having its center located at a third distance approximately equal to the first distance to the longitudinal axis,

the cloverleaf structure further defining a height measured from a point on a perimeter of the second virtual circle to a neck directly away from the longitudinal axis in relation to the second virtual circle and between an adjacent first virtual circle and second virtual circle,

the first radius, second radius, third radius, and height being configured to provide a lateral stiffness of the expandable basket assembly within a predetermined range,

wherein the first radius measures between 31% and 35% of the height,

wherein the second radius measures between 37% and 41% of the height,

wherein the third radius measures between 31% and 35% of the height, and

wherein a minimum width of the sinusoidal-like member measures between 23% and 27% of the height.

2 . The medical probe according to claim 1 , the first radius, second radius, third radius, and height being configured to provide a maximum peak stress during retraction of the expandable basket assembly into an intermediate catheter such that the maximum peak stress is less than a predetermined threshold.

3 . The medical probe according to claim 1 ,

wherein the first radius measures about 33% of the height,

wherein the second radius measures about 39% of the height,

wherein the third radius measures about 33% of the height, and

wherein a minimum width of the sinusoidal-like member measures about 25% of the height.

4 . The medical probe according to claim 1 , wherein the central area comprises approximately 0.8 mm-squared area, a fourth virtual circle encircling the sinusoidal-like member comprises an area approximately 14 times greater than the central area and the second distance is approximately ½ that of the first distance.

5 . The medical probe according to claim 4 , in which the sinusoidal-like member is tangential to a central circle of the central area.

6 . The medical probe according to claim 1 , further comprising a plurality of electrically insulative jackets each disposed between a respective spine of the plurality of spines and a respective electrode, thereby electrically isolating the respective electrode from the respective spine.

7 . The medical probe according to claim 6 ,

wherein the sinusoidal-like member comprises an inner arc around the second virtual circle such that the inner arc is entirely positioned less than the second distance from the longitudinal axis,

wherein the sinusoidal-like member comprises an outer portion around the first virtual circle and around the second virtual circle such that the outer portion is entirely positioned greater than the second distance from the longitudinal axis, and

wherein a majority of the outer portion of the sinusoidal-like member is covered by a respective jacket of the electrically insulative jackets.

8 . The medical probe according to claim 7 , wherein a distal portion of each of the plurality of electrically insulative jackets tapers outward and inward, following a curvature of the outer portion of the sinusoidal-like member.

9 . The medical probe according to claim 7 , a distal portion of each of the plurality of electrically insulative jackets abuts the distal portion of an adjacent insulative jacket.

10 . The medical probe according to claim 6 , further comprising:

two electrodes coupled to a respective spine for each spine of the plurality of spines, the plurality of spines comprising a first spine and a second spine, the first spine having a single cross-section extending from a proximal portion of the first spine to approximately a midpoint of the first spine and thereafter dividing into at least two discrete cross sections to the distal spine portion of the first spine, and the second spine having at least two discrete cross sections extending from a proximal portion of the second spine to approximately a midpoint of the second spine and thereafter combining into a single cross section extending to the distal spine portion of the second spine.

11 . A medical probe, comprising:

an expandable basket assembly configured to be coupled to a distal end of a tubular shaft, the basket assembly comprising:

a plurality of spines extending along a longitudinal axis from a proximal central proximal spine portion to a distal spine portion, the distal spine portion defining a cloverleaf structure disposed radially around the longitudinal axis, the cloverleaf structure defining a central cutout with a central area disposed about the longitudinal axis, the cloverleaf structure comprising a sinusoidal-like member extending from one spine to an adjacent spine in a direction around the longitudinal axis, the sinusoidal-like member meanders around:

(a) a first virtual circle having a first radius, the first virtual circle having its center located at a first distance to the longitudinal axis,

(b) a second virtual circle having a second radius, the second virtual circle having its center located at a second distance smaller than the first distance to the longitudinal axis, and

(c) a third virtual circle having a third radius approximately equal to the first radius, the third virtual circle having its center located at a third distance approximately equal to the first distance to the longitudinal axis,

the cloverleaf structure further defining a height measured from a point on a perimeter of the second virtual circle to a neck directly away from the longitudinal axis in relation to the second virtual circle and between an adjacent first virtual circle and second virtual circle,

the first radius, second radius, third radius, and height being configured to provide a lateral stiffness of the expandable basket assembly within a predetermined range,

wherein the central area comprises approximately 0.8 mm-squared area, a fourth virtual circle encircling the sinusoidal-like member comprises an area approximately 14 times greater than the central area and the second distance is approximately ½ that of the first distance.

12 . The medical probe according to claim 11 , the first radius, second radius, third radius, and height being configured to provide a maximum peak stress during retraction of the expandable basket assembly into an intermediate catheter such that the maximum peak stress is less than a predetermined threshold.

13 . The medical probe according to claim 11 ,

wherein the first radius measures about 33% of the height,

wherein the second radius measures about 39% of the height,

wherein the third radius measures about 33% of the height, and

wherein a minimum width of the sinusoidal-like member measures about 25% of the height.

14 . The medical probe according to claim 11 , in which the sinusoidal-like member is tangential to a central circle of the central area.

15 . The medical probe according to claim 11 , further comprising a plurality of electrically insulative jackets each disposed between a respective spine of the plurality of spines and a respective electrode, thereby electrically isolating the respective electrode from the respective spine.

16 . The medical probe according to claim 15 ,

wherein the sinusoidal-like member comprises an inner arc around the second virtual circle such that the inner arc is entirely positioned less than the second distance from the longitudinal axis,

wherein the sinusoidal-like member comprises an outer portion around the first virtual circle and around the second virtual circle such that the outer portion is entirely positioned greater than the second distance from the longitudinal axis, and

wherein a majority of the outer portion of the sinusoidal-like member is covered by a respective jacket of the electrically insulative jackets.

17 . The medical probe according to claim 16 , wherein a distal portion of each of the plurality of electrically insulative jackets tapers outward and inward, following a curvature of the outer portion of the sinusoidal-like member.

18 . The medical probe according to claim 16 , a distal portion of each of the plurality of electrically insulative jackets abuts the distal portion of an adjacent insulative jacket.

19 . The medical probe according to claim 15 , further comprising:

two electrodes coupled to a respective spine for each spine of the plurality of spines, the plurality of spines comprising a first spine and a second spine, the first spine having a single cross-section extending from a proximal portion of the first spine to approximately a midpoint of the first spine and thereafter dividing into at least two discrete cross sections to the distal spine portion of the first spine, and the second spine having at least two discrete cross sections extending from a proximal portion of the second spine to approximately a midpoint of the second spine and thereafter combining into a single cross section extending to the distal spine portion of the second spine.

20 . The medical probe according to claim 11 ,

wherein the first radius measures between 31% and 35% of the height,

wherein the second radius measures between 37% and 41% of the height,

wherein the third radius measures between 31% and 35% of the height, and

wherein a minimum width of the sinusoidal-like member measures between 23% and 27% of the height.