Ex Parte Zhang et al

Patent Trials and Appeals Board

Mar 13, 2013

11208922 - (D) (P.T.A.B. Mar. 13, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte YUNLONG ZHANG, JAMES O. GILKERSON,
YONGXING ZHANG, and BOYCE MOON
____________

Appeal 2010-006527
Application 11/208,922
Technology Center 3700
____________

Before LINDA E. HORNER, GAY ANN SPAHN, and
MICHAEL L. HOELTER, Administrative Patent Judges.

SPAHN, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Yunlong Zhang et al. (Appellants) seek our review under 35 U.S.C.
§ 134 of the Examiner’s rejection of claims 1-12, 14, 16, and 18-31.
Appellants cancelled claims 13, 15, and 17. We have jurisdiction under 35
U.S.C. § 6(b).
We REVERSE.
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The Claimed Subject Matter
The claimed subject matter relates to “implantable medical devices
and, in particular, . . . to systems and methods for detecting events related to
cardiac activity.” Spec. 1, ll. 6-8. Claims 1, 12, 19, 24, and 29 are the
independent claims on appeal. Claim 1, reproduced below, with emphasis
added, is illustrative of the appealed subject matter.
1. A system comprising:
a medical device including:
a cardiac cycle sensing circuit, the sensing circuit
configured to provide a sensed cardiac cycle;
an impedance measurement circuit configured to provide
an intracardiac impedance signal; and
a controller circuit coupled to the impedance
measurement circuit, the controller circuit configured to detect
tachyarrhythmia from the intracardiac impedance signal using
at least two of:
a cardiac-cycle-to-cardiac-cycle change in a value of a
baseline intracardiac impedance value calculated, for a
particular cardiac cycle, to represent the baseline intracardiac
impedance for that particular cardiac cycle;
a cardiac-cycle-to-cardiac-cycle change in a value of
maximum intracardiac impedance value calculated, for a
particular cardiac cycle, to represent the maximum
intracardiac impedance for that particular cardiac cycle; and
a cardiac-cycle-to-cardiac-cycle change in a slope value
of the intracardiac impedance waveform signal, for a particular
cardiac cycle, the slope value measured at a time
corresponding to one-half of a time interval over which a
maximum intracardiac impedance change occurs during that
particular cardiac cycle.

Independent claims 12, 24, and 29 are directed to a method
comprising, inter alia, the step of “measuring intracardiac impedance
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parameters from the waveform including at least two of” the three
highlighted parameters as quoted in independent claim 1 supra.
Independent claim 19 is directed to a method comprising, inter alia,
the step of “determining whether the tachyarrhythmia is stable using
intracardiac impedance parameters derived from the intracardiac impedance
signal wherein the intracardiac impedance parameters include at least two
of” the three highlighted parameters as quoted in independent claim 1 supra.

The Rejections
The following Examiner’s rejections, under 35 U.S.C. § 103(a), are
before us for review:
I. claims 1-4, 7-12, 14, 16, and 18-31 as unpatentable over
Huvelle (US 6,522,914 B1, issued Feb. 18, 2003); and
II. claims 5 and 6 as unpatentable over Huvelle and Weiss (US
5,179,946, issued Jan. 19, 1993).

OPINION
Rejection I – Obviousness based on Huvelle
The Examiner finds that Huvelle substantially discloses the subject
matter of independent claims 1, 12, 19, 24, and 29, “except for said system
and method measuring, deriving impedance parameters and/or detecting
tacharrhythmia from an intracardiac impedance signal by using at least two
of” the highlighted three parameters as quoted in claim 1 supra. Ans. 3-5.
The Examiner also finds Huvelle discloses:
that it is known to continuously measure intracardiac
impedance values by computing intracardiac impedance derived
parameter(s) and/or values (HCA) for each cardiac cycle, in
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which the disclosed HCA values are computed by finding the
summation and/or average of the jth impedance signal sample
per cardiac cycle of nth samples for m number of cardiac
samples in order to provide an averaged or baseline impedance
derived parameter per cardiac cycle, and cycle-to-cycle change
in a slope value of an intracardiac impedance waveform signal
[e.g., (col 4, ln 1-40), (col 9, ln 55-67) & (col 10, ln 1-13)].
Ans. 5 (brackets in original). The Examiner concludes that it would have
been obvious to one of ordinary skill in the art “to have incorporated in
Huvelle . . . the use of at least two of” the three highlighted parameters as
quoted in claim 1 supra, “in order to provide the predictable results
pertaining to providing intracardiac impedance derived parameters and
computed values for each cardiac cycle sampled so as to adjust therapy, such
as for the anti-tachycardia pacing used to treat cardiac patients based on the
continuous change of the cardiac cycles sampled.” Ans. 5-6 (citing Huvelle,
col. 4, ll. 1-40).
Appellants note “Huvelle states that it can be observed on 1/HCA
curve 1230 . . . that the higher the metabolic demand is, the deeper and the
wider the dips are at low pacing rates, and this indicates that the pacing rate
is not sufficient.” App. Br. 17 (citing Huvelle, col. 10, ll. 1-5). Appellants
argue that if the Examiner is “equat[ing] the reference to wider and deeper
segments of this inverse area-ratio curve to the slope of the intracardiac
impedance waveform signal,” then “the derived 1/HCA curve is clearly not
the same as an intracardiac impedance waveform signal, and Huvelle clearly
does not disclose using a change in a slope value of the intracardiac
impedance waveform signal.” Id. Appellants also argue that “Huvelle uses,
(1) a graphical construction involving a decreasing 1/HCA curve, and (2) a
Vrate plot, to determine a hemodynamic lower rate limit (HLRL)” and
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“[t]hus, the cited portions of Huvelle relate to using a decreasing 1/HCA
curve to find the HLRL, which is merely used to define a Hemodynamic
Pacing Range,” but “fails to establish ‘detecting tachyarrhythmia using . . . a
cardiac-cycle-to-cardiac-cycle change in a slope value of the intracardiac
impedance waveform signal . . . .’” Id. (quoting claim 1) (emphasis
omitted).
The Examiner responds that Huvelle discloses
a method of controlling cardiac activities and implantable
devices based on an intracardiac impedance-derived parameter,
HCA, in which HCA values are computed in order to provide a
cycle-to-cycle change in a slope value measured at a time of
one-half a time interval over a maximum intracardiac
impedance change of an intracardiac waveform [e.g., (col 9, ln
55-67)-(col 10, ln 1-13)] and computed to find the summation
and/or average of the jth impedance signal sample per cardiac
cycle of nth samples for m number of cardiac samples in order
to provide an averaged or baseline impedance derived
parameter per cardiac cycle [e.g., (col 4, ln 1-40), (col 9, ln 55-
67) & (col 10, ln 1-13)], therefore providing said method and
devices with the capability of providing a cycle-to-cycle change
in a value of a baseline intracardiac impedance value and a
cycle-to-cycle change in a slope value of the intracardiac
impedance waveform signal as is instantly claimed.
Ans. 7 (brackets in original). Thus, we understand the Examiner’s position
to be that either Huvelle teaches the claimed baseline and slope parameters
of the three recited parameters or Huvelle suggests and could be modified to
have the claimed baseline and slope parameters of the three recited
parameters. The Examiner never addresses the claimed maximum peak
impedance value Zmax parameter.
Appellants’ Figure 5A depicts a measured intracardiac impedance
waveform 510 with the segment of the impedance waveform 510 between
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the vertical bars 525 being the intracardiac impedance over a cardiac cycle.
Spec. 8, ll. 18-26. Appellants’ Specification indicates that “controller circuit
420 of FIG. 4 derives many intracardiac impedance parameters from
intracardiac impedance waveforms 510,” namely, baseline impedance value
Z0, area Zarea between the impedance signal waveform 510 and the baseline
Z0, maximum peak impedance value Zmax, time interval of maximum
impedance change TZ0-Zmax, and slope of the intracardiac impedance wave
form measured at ½ TZ0-Zmax 530, or S½TZ0-Zmax. Spec. 8, l. 27 through Spec.
9, l. 21.
Huvelle’s Figure 2 depicts an intracardiac impedance waveform 202
corresponding to a single cardiac cycle which is similar to Appellants’
measured intracardiac impedance waveform 510. Huvelle, col. 2, ll. 30-32.
In contrast to those intracardiac impedance parameters described in
Appellants’ Specification and mentioned supra, Huvelle describes yet
another “intracardiac impedance derived parameter, [namely,] Half Cycle
Activity (HCA),” and “[r]eferring to FIG. 2, HCA corresponds to the dark-
shaded area 204 divided by the sum of the dark-shaded area 204 and the
light-shaded area 206 underneath the impedance wave form 202 of a single
cardiac cycle.” Huvelle, col. 4, ll. 2-4, 24-27. Huvelle also describes
numerous experiments performed on an ambulatory dog. Huvelle, col. 7, l.
1 through col. 12, l. 48. The Examiner particularly points to Experiment VI,
in which the Hemodynamic Upper Rate Level (HURL) and Hemodynamic
Lower Rate Level (HLRL) are determined, as support for Huvelle teaching
or suggesting a cycle-to-cycle change in slope value. Ans. 5 and 7 (citing
Huvelle, col. 9, ll. 51-53). Huvelle’s Figures 12a-12d are discussed in
connection with Experiment VI and these figures show overlaid plots of the
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changes over time in several cardiac cycles in (a) the treadmill speed, (b)
ventricular rate, (c) atrial rate, and (d) 1/HCA value, respectively, in the
ambulatory dog engaged in an exercise on a treadmill, demonstrating the
HURL and HLRL determination. Huvelle, col. 3, ll. 1-5.
In view of the above-discussed disclosure of Huvelle, we are
persuaded by Appellants’ arguments that Huvelle does not disclose or
suggest a cardiac-cycle-to-cardiac-cycle change in a slope value of the
intracardiac impedance waveform signal as suggested by the Examiner.
Huvelle’s Experiment VI and Figures 12a-12d do not support the
Examiner’s position that “HCA values are computed in order to provide a
cycle-to-cycle change in a slope value.” Ans. 7. HCA values are ratios of
areas and involve graph variables different from those recited in the claims.
We agree with Appellants that the Examiner’s reliance on the 1/HCA curve
1230 shown in Figure 12d to establish the slope value is misplaced since it is
the intracardiac impedance curve 202 shown in Figure 2 that the Examiner
should be relying on to generate the slope values. Even if a slope value
could be computed from the 1/HCA curve 1230 shown in Huvelle’s Figure
2d, it would be the wrong slope value since it would not be a slope value
associated with the intracardiac impedance curve 202 shown in Huvelle’s
Figure 2. Thus, the Examiner has failed to show that Huvelle meets the
claim language of using at least two the three recited parameters because the
Examiner has not addressed the maximum peak intracardiac impedance
value and has failed to show that the slope value can be computed from
Huvelle’s HCA parameter.
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Accordingly, we do not sustain the Examiner’s rejection of claims 1-
4, 7-12, 14, 16, and 18-31 under 35 U.S.C. § 103(a) as unpatentable over
Huvelle.

Rejection II – Obviousness based on Huvelle and Weiss
The Examiner’s rejection relies on the erroneous finding that Huvelle
discloses the capability of providing a cycle-to-cycle change in a slope value
of the intracardiac impedance waveform. Appellants argue that Weiss fails
to cure the deficiency of Huvelle. App. Br. 18. We agree. Accordingly, we
do not sustain the Examiner’s rejection of claims 5 and 6 under 35 U.S.C.
§ 103(a) as unpatentable over Huvelle and Weiss.

DECISION
We reverse the Examiner’s decision to reject claims 1-12, 14, 16, and
18-31.

REVERSED

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