Medtronic 4965-15 Technical Manual

CAPSURE® EPI 4965

Steroid eluting, unipolar, epicardial lead

Technical Manual

Caution: Federal law (USA) restricts this device to sale
by or on the order of a physician.

The following list includes trademarks or registered trademarks
of Medtronic in the United States and possibly in other countries.
All other trademarks are the property of their respective owners.

CapSure, Medtronic

Contents

1 Device description 3
2 Accessory descriptions 3
3 Indications 4
4 Contraindications 4
5 Warnings and precautions 4
6 Adverse events 6
7 Clinical studies 9
8 Directions for use 23

9 Detailed device description 30
10 Service 32
11 Medtronic warranty 32

1 Device description

The Medtronic CapSure Epi Model 4965 steroid eluting, unipolar,
epicardial lead is designed for pacing and sensing in either the atrium
or ventricle. Two leads may be used for bipolar pacing.

The porous electrode surface is platinized with platinum black and has
been coated with the steroid dexamethasone sodium phosphate.

The electrode contains a maximum of 1.0 mg of dexamethasone
sodium phosphate, a portion of which is in a silicone rubber binder.
Upon exposure to body fluids, the steroid elutes from the electrode.
Steroid suppresses the inflammatory response that is believed to
cause threshold rises typically associated with implanted pacing
electrodes.

The Model 4965 lead’s silicone suture pad is a triangular shape with 2
suture holes and grooves. The lead also features an MP35N
nickel-alloy conductor, silicone rubber insulation, and a unipolar
connector (IS-11 UNI).

1.1 Contents of package

The lead and accessories are supplied sterile. Each package contains:

●

1 Model 4965 lead

●

1 lead end cap

●

1 tunneler

●

product literature

2 Accessory descriptions

Dispose of all single-use accessories according to local environmental
requirements.

Lead end cap – A seal that is placed on the tip of a lead when the lead
is abandoned in the body to prevent transmission of electrical signals.

1

IS-1 refers to an International Standard (ISO 5841-3) whereby pulse generators
and leads so designated are assured of a basic mechanical fit.

3

Tunneler – A tool used to pass a lead from its point of insertion to the
subcutaneous pocket.

3 Indications

The Model 4965 lead is designed to be used with a pulse generator as
part of a cardiac pacing system. The lead has application where
implantable epicardial atrial or ventricular, single chamber or dual
chamber pacing systems are indicated.

4 Contraindications

●

The lead should not be used on a patient with a heavily infarcted
or fibrotic myocardium. It is also contraindicated for the patient
whose myocardium is suffused with fat.

●

Do not use this device in patients for whom a single dose of 1.0 mg
of dexamethasone sodium phosphate may be contraindicated.

5 Warnings and precautions

Inspecting the sterile package – Inspect the sterile package with

care before opening it.

●

Contact your Medtronic representative if the seal or package is
damaged.

●

Do not store this product above 40 °C (104 °F).

●

Do not use the product after its expiration date.

Sterilization – Medtronic has sterilized the package contents with
ethylene oxide before shipment. This lead is for single use only and is
not intended to be resterilized.

Single use – The lead and accessories are for single use only.

Necessary hospital equipment – Keep external defibrillation

equipment nearby for immediate use during acute lead system testing,
the implant procedure, or whenever arrhythmias are possible or
intentionally induced during post-implant testing.

Line-powered and battery-powered equipment – An implanted
lead forms a direct current path to the myocardium. During lead implant
and testing, use only battery-powered equipment or line-powered
equipment specifically designed for this purpose to protect against
fibrillation that may be caused by alternating currents. Line-powered
equipment used in the vicinity of the patient must be properly
grounded. Lead connector pins must be insulated from any leakage
currents that may arise from line-powered equipment.

Concurrent devices – Output pulses, especially from unipolar
devices, may adversely affect device sensing capabilities. If a patient
requires a separate stimulation device, either permanent or temporary,
allow enough space between the leads of the separate systems to
avoid interference in the sensing capabilities of the devices. Previously
implanted pulse generators and implantable cardioverter defibrillators
should generally be explanted.

Steroid use – It has not been determined whether the warnings,
precautions, or complications usually associated with injectable
dexamethasone sodium phosphate apply to the use of this highly
localized, controlled-release lead. For a list of potential adverse
effects, refer to the Physicians’ Desk Reference.

4

Handling the steroid tip – Reducing the available amount of steroid
may adversely affect low-threshold performance. Avoid reducing the
amount of steroid available prior to lead implant.

●

Do not allow the electrode surface to come in contact with surface
contaminants.

●

Do not wipe or immerse the electrode in fluid, except blood, at the
time of implant.

Handling the lead – Before implanting the lead remove the tip
protector.

●

If the lead is damaged, do not implant it. Return the lead to a
Medtronic representative.

●

Protect the lead from materials that shed particles such as lint and
dust. Lead insulators attract these particles.

●

Handle the lead with sterile surgical gloves that have been rinsed
in sterile water or a comparable substance.

●

Do not severely bend, kink, or stretch the lead.

●

Do not use surgical instruments to grasp the lead or connector pin.

●

Do not immerse leads in mineral oil, silicone oil, or any other liquid,
except blood, at the time of implant.

Chronic repositioning or removal – Chronic repositioning or
removal of the lead after it has been implanted in the patient is not
recommended. If removal is unavoidable, return the lead to Medtronic.

●

If a lead is abandoned, it should be capped to avoid transmitting
electrical signals from the pin to the heart.

●

A lead that has been cut off should have the remaining lead end
sealed and it should be sutured to adjacent tissue to avoid
migration.

●

Repositioning the lead after it has been implanted may adversely
affect a steroid lead’s low-threshold performance.

Magnetic resonance imaging (MRI) – An MRI is a type of medical
imaging that uses magnetic fields to create an internal view of the body.
Do not conduct MRI scans on patients who have this device or lead
implanted. MRI scans may result in serious injury, induction of
tachyarrhythmias, or implanted system malfunction or damage.

Diathermy treatment (including therapeutic ultrasound) –

Diathermy is a treatment that involves the therapeutic heating of body
tissues. Diathermy treatments include high frequency, short wave,
microwave, and therapeutic ultrasound. Except for therapeutic
ultrasound, do not use diathermy treatments on cardiac device
patients. Diathermy treatments may result in serious injury or damage
to an implanted device and leads. Therapeutic ultrasound is the use
of ultrasound at higher energies than diagnostic ultrasound to bring
heat or agitation into the body. Therapeutic ultrasound is acceptable if
treatment is performed with a minimum separation distance of 15 cm
(6 in) between the applicator and the implanted device and leads.

5

6 Adverse events

The clinical investigation of the Model 4965 Pacing lead studied 661
devices implanted in 381 patients for a total of 9681 cumulative device
months of experience (3054 Atrial, 6627 Ventricular). Mean duration
of implantation was 14.6 months (range 0 to 62 months). Forty-eight
(48) patients (12.6%) with Model 4965 pacing leads died during the
course of the clinical study. None of the deaths were determined to be
lead related. Lead related adverse events (AEs), including 43
complications (6.5% of leads) and 57 observations (8.6% of leads),
were reported during the clinical investigation. The adverse events that
occurred during more than one time are summarized in Table 1 and
Table 2.

Table 1. Mean duration of implantation is 14.6 months (range 0 - 62 months).

Frequency of adverse events for atrial leads

Type of adverse
event AE

Observations

Muscle stimulation 12 5.4%

Undersensing 6 2.7%

Oversensing 6 2.7%

Elevated thresholds 5 2.2%

Total observa-

a

tions

Complications
(loss of lead)

Lead fracture 5 2.2%

Total complica-

b

tions

a

Observations are adverse events which are corrected by non-invasive
measures (e.g. reprogramming).

b

Complications are adverse events that resulted in loss of the lead function (e.g.
unable to sense or unable to pace the heart).

# of
leads
(n=224)

29 12.9%[8.6

5 2.2%[1.0 -

% of leads
[95% CI]

[2.4 - 8.3%]

[0.6- 4.8%]

[0.6- 4.8%]

[1.0 - 5.2%]

- 17.3%]

[1.0 - 5.2%]

5.2%]

# of
patients
(n=201)

12 6.0%

6 3.0%

6 3.0%

5 2.5%

29 14.4%[9.6

5 2.5%

5 2.5%[1.1 -

% of
patients
[95% CI]

[2.7 - 9.2%]

[0.6 - 5.3%]

[0.6 - 5.3%]

[1.1 - 5.8%]

- 19.3%]

[1.1 - 5.8%]

5.8%]

Table 2. Mean duration of implantation is 14.6 months (range 0 - 62

months).

Frequency of adverse events for ventricular leads

Type of adverse
event AE

Observations

Elevated thresh­olds

Undersensing 9 2.1%

# of leads
(n=437)

10 2.3%

% of leads
[95% CI]

[0.9 - 3.7%]

[0.7- 3.4%]

# of
patients
(n=355)

10 2.8%

9 2.5%

% of
patients
[95% CI]

[1.1 - 4.5%]

[0.9 - 4.2%]

6

Table 2. Mean duration of implantation is 14.6 months (range 0 - 62
months). (continued)

Frequency of adverse events for ventricular leads

Type of adverse
event AE

# of leads
(n=437)

% of leads
[95% CI]

patients
(n=355)

Observations

# of

Muscle stimulation 7 1.6%

7 2.0%

[0.4 - 2.8%]

Oversensing 2 0.5%

2 0.6%

[0.2- 1.7%]

Total observa-

a

tions

28 6.4%[4.1 -

8.7%]

28 7.9%[5.1 -

Complications
(loss of lead)

Lead fracture 20 4.6%

16 4.5%

[2.6 - 6.5%]

Exit block 6 1.4%

5 1.4%

[0.3 - 2.5%]

Other causes 5 1.1%

4 1.1%

[0.6 - 2.7%]

Elevated pacing
thresholds

Loss of capture 3 0.7%

4 0.9%

[0.4 - 2.4%]

4 1.1%

3 0.8%

[0.3 - 2.0%]

Total complica-

b

tions

a

Observations are adverse events which are corrected by non-invasive
measures (e.g. reprogramming).

b

Complications are adverse events that resulted in loss of the lead function (e.g.

38 8.7%[6.1 -

11.3%]

32 9.0%[6.0 -

unable to sense or unable to pace the heart).

% of
patients
[95% CI]

[0.5 - 3.4%]

[0.2 - 2.1%]

10.7%]

[2.3 - 6.7%]

[0.7 - 3.3%]

[0.5 - 2.9%]

[0.5 - 2.9%]

[0.4 - 2.5%]

12.0%]

There are additional complications related to the use of epicardial
leads that include, but are not limited to, the following:

●

fibrillation

●

heart wall damage

●

cardiac tamponade

●

muscle or nerve stimulation

●

pericardial rub

●

infection

In addition, the lead may not perform optimally in patients with
thin-walled myocardiums.

Another complication, which has been referenced in the literature, is
the potential for increased risk of inducing tachyarrhythmias when
using 2 leads for bipolar pacing. This is thought to be due to the equal
surface area of the anodal and cathodal electrodes. If pacing stimuli
are observed to be falling on the T-wave, it may help to unipolarize the
system.

The potential complications listed above may occur at a higher rate
with the use of these leads in pediatric patients.

7

Typical complications resulting in patient symptoms can often be
resolved as follows in the following chart.

Complication Symptom

Lead dislodgement Intermittent or continu-

Lead conductor fracture
or insulation failure

Threshold elevation or
exit block

a

Transient loss of capture or sensing may occur for a short time following a
surgery until lead stabilization takes place. If stabilization does not occur, lead
dislodgement may be suspected.

ous loss of capture or

a

sensing

Intermittent or continu­ous loss of capture or

a

sensing

Loss of capture

a

Corrective action to
be considered

Replace the lead

Replace the lead

Adjust the pulse gener­ator output or replace
the lead.

The Model 4965 Pacing Lead post-approval study studied 98 leads
implanted in 73 adult (>19 years old at implant) patients for a total of
2711 months of cumulative device months of experience. Mean
duration of implantation was 27.66 months (range 0 to 146.73 months).
Eighteen (18) patients with Model 4965 Pacing Leads died during the
course of the post-approval study. None of the deaths were
determined to be lead-related. Lead-related events including two
complications (2.04% of leads) and six observations (8.16% of leads)
were reported during the clinical study, Table 3.

Table 3. Frequency of Adverse Events in the Model 4965 Post Approval Study

Type of adverse
event

Reported Observa­tions

Threshold rise, sud­den

Pacemaker Syn­drome

Lead electrically
abandoned:

Late local ventricle
sensing

Lead surgically aban­doned:

RV lead problem 1 1.02%

# of leads
(n=98)

- - - -

1 1.02%

2 2.04%

1 1.02%

% of
leads
[95% CI]

(0.03%,

5.55%)

(0.25%,

7.18%)

(0.03%,

5.55%)

(0.03%,

5.55%)

# of
patients
(n=73)

1 1.37%

1 1.37%

1 1.37%

1 1.37%

% of
patients
[95% CI]

(0.03%,

7.40%)

(0.03%,

7.40%)

(0.03%,

7.40%)

(0.03%,

7.40%)

8

Table 3. Frequency of Adverse Events in the Model 4965 Post
Approval Study (continued)

Type of adverse
event

Lead surgically aban­doned:

System upgrade 1 1.02%

Lead surgically aban­doned:

Unspecified 2 2.04%

Total observations 8 8.16%

Lead Related Com­plications

Failure to capture 1 1.02%

Lead conductor frac­ture

Total complications 2 2.04%

# of leads
(n=98)

1 1.02%

% of
leads
[95% CI]

(0.03%,

5.55%)

(0.25%,

7.18%)

(3.59%,

15.45%)

(0.03%,

5.55%)

(0.03%,

5.55%)

(0.25%,

7.18%)

# of
patients
(n=73)

1 1.37%

1 1.37%

6 8.22%

1 1.37%

1 1.37%

2 2.74%

% of
patients
[95% CI]

(0.03%,

7.40%)

(0.03%,

7.40%)

(0.03%,

7.40%)

(0.03%,

7.40%)

(0.03%,

7.40%)

(0.33%,

9.55%)

For a Model 4965 survival estimate generated from the Medtronic
active prospective surveillance study, refer to the CRDM Product
Performance Report. This report is available
at www.Medtronic.com/CRDMProductPerformance.

7 Clinical studies

7.1 Model 4965 Clinical Study summary of clinical results

The Model 4965 lead was studied in 381 patients who received 661
leads for a total of 9681 device months experience. Six hundred (600)
of these leads were implanted in 349 pediatric patients and 61 leads
were implanted in 32 adult patients. Data were collected prospectively
at 2 weeks and 1, 3, 6, 9, and 12 months post implant at 56 investigative
centers. The median patient age for the pediatric population was 2.3
years (range 0 - 18.6 years); 57.3% of the pediatric patients were male.
For the adult population, the median patient age was 34.3 (range 19.2 -

79.6 years); 46.9% of the adult patients were male.

7.1.1 Primary objectives

Primary objective one – To demonstrate the safety of the Model 4965

lead by measuring Loss of Lead survival performance in four
categories. The categories were loss of lead due to 1) Conductor Coil
Fracture (Fx) 2) Fx plus Loss of Capture (LOC) 3) Fx, LOC plus

9

Elevated Thresholds (ET) and Exit Block (EB) 4) Overall loss of lead
(Fx, LOC, ET, EB plus “loss of sensing” and “other”). See Table 5.

Primary objective two – To demonstrate the effective acute and
chronic pacing and sensing performance of the Model 4965 lead by
measuring electrical threshold performance of the device.

Results:2 Patients in the study who received the Model 4965 device

via a left thoracotomy surgical approach were found to have a
statistically higher risk of lead fracture than those patients treated with
other surgical approaches (p<0.01). A comparison of surgical implant
techniques for the effect on lead fracture is shown in Table 4.

Table 4. A Cox Regression with a covariate of surgical technique for
effect on fracture of pediatric leads was used to calculate the risk
associated with each type of surgical technique. No effect is noted by
a confidence interval of the risk ratio which contains 1.

Number Frac-

Implant technique

Median sternotomy 2/250 (0.8%)

Subxiphoid 4/149 (2.7 %)

Left thoracotomy 17/157 (10.8%)

Subcostal 1/16 (6.3%)

Other 1/22 (4.5%)

tured/Total (%) [95%
C.I.] Risk Ratio [95% C.I.]

0.1 [0.03 - 0.6]

[0.2 - 2.9%]

0.6 [0.2 - 1.8]

[1.1 - 6.8%]

5.2 [2.2 - 12.3]

[6.0 - 15.7%]

2.9 [0.4 - 22.8]

[1.5 - 30.3%]

0.5 [0.06 - 3.9]

[1.1 - 22.9%]

The Model 4965 lead demonstrated acceptable survival rates at 12
months in the four identified categories:

Table 5. Loss of lead survival performance in pediatric patients (n=594 leads).

Category 12 month survival

Coil fractures 96.3%

Coil fractures + Loss of capture 95.5%

Coil fractures + Loss of capture + Elevated
thresholds + Exit block

Overall loss of lead 93.6%

94.8%

Pacing and sensing thresholds were also found to be acceptable.
Furthermore, the Model 4965 lead demonstrated no peaking
phenomenon in the acute phase of implantation and had low, stable,
chronic stimulation thresholds.

2

Data presented are from the pediatric cohort only.

10

The lead performance of the primary outcome study variables is

Follow-up time in months (Implant at month 0)

Unipolar atrial pulse width thresholds at 2.5 V in the pediatric

cohort

Threshold in ms

Follow-up time in months (Implant at month 0)

Unipolar ventricular pulse width thresholds at 2.5 V in the pediatric

cohort

Threshold in ms

represented graphically on the following pages. The electrical data
presented in Figure 1 through Figure 4, followed by Kaplan-Meier
survival curves that display the safety performance of the Model 4965
lead in Figure 5 through Figure 8 .

Figure 1. Unipolar atrial pulse width thresholds at 2.5 V, Mean ± 1.5 standard error of the mean (SEM), n displayed at each data point. Pediatric patients with unipolar atrial leads: n-total=178.

Figure 2. Unipolar ventricular pulse width thresholds at 2.5 V, Mean ±

1.5 standard error of the mean (SEM), n displayed at each data point.
Pediatric patients with unipolar ventricular leads: n-total=320.

11

Figure 3. Unipolar atrial sensitivity thresholds, Mean ± 1.5 standard

Follow-up time in months (Implant at month 0)

Unipolar atrial sensitivity thresholds in the pediatric cohort

Threshold in mV

Follow-up time in months (Implant at month 0)

Unipolar ventricular sensitivity thresholds in the pediatric cohort

Threshold in mV

error of the mean (SEM), n displayed at each data point. Pediatric
patients with atrial unipolar leads: n-total=178.

Figure 4. Unipolar ventricular sensitivity thresholds, Mean ± 1.5 standard error of the mean (SEM), n displayed at each data point. Pediatric patients with unipolar ventricular leads: n-total=320.

Figure 5. Kaplan-Meier Survival from loss of lead due to lead fracture
in the pediatric cohort, Rate ± 1.5 standard error of the mean (SEM).

12

Eleven (11) failures in 594 leads, 233 leads at end-point, n=344

Time in days

Survival from loss due to lead fracture in the pediatric cohort

Survival in percent

Time in days

Survival from loss due to lead fracture and loss of capture in the

pediatric cohort

Survival in percent

patients.

Figure 6. Kaplan-Meier Survival from loss of lead due to lead fracture and loss of capture in the pediatric cohort, Rate ± 1.5 standard error of the mean (SEM). Fourteen (14) failures in 594 leads, 233 leads at end-point, n=344 patients.

Figure 7. Kaplan-Meier Survival from loss of lead due to lead fracture,
loss of capture, exit block and elevated thresholds in the pediatric

13

cohort, Rate ± 1.5 standard error of the mean (SEM). Seventeen (17)

Time in days

Survival from loss due to lead fracture, loss of capture, exit

block, and elevated threshods in the pediatric cohort

Survival in percent

Time in days

Survival from overall loss in the pediatric cohort

Survival in percent

failures in 594 leads, 233 leads at end-point, n=344 patients.

Figure 8. Kaplan-Meier Survival from overall loss of lead in the pediatric cohort, Rate ± 1.5 standard error of the mean (SEM). Twenty-two (22) failures in 594 leads, 233 leads at end-point, n=344 patients.

7.2 Model 4965 Post Approval Study summary of clinical results

Study title: Model 4965 Post Approval Study

Product: Medtronic Model 4965 CAPSURE EPI steroid-eluting

unipolar epicardial pacing lead

Number of centers: 119

14

Number of subjects: 73 enrolled

Table 6. Study summary

Number of subjects 73 subjects

Number of subjects with ≥ one year of follow-up 51 subjects

Cumulative device follow-up time 2711 months

Average device follow-up time 27.66 months

Number of enrolling centers 21 centers

Final report data cut-off date 17 February 2011

7.2.1 Study objective

Medtronic conducted the Model 4965 Post Approval Study to perform
long term surveillance on the CAPSURE EPI Model 4965 lead. This
study was required by the FDA as part of the requirement to satisfy the
PMA conditions of product approval.

7.2.2 Study design

The Model 4965 Post Approval Study was a prospective,
non-randomized, multi-center study conducted at 119 centers in the
United States, Canada, and Europe. The study required 50 adult
subjects, >19 years at implant, to be enrolled and followed for one-year
post-implant. Data for the Model 4965 Post Approval Study was
collected following the Medtronic System Longevity Study protocol.

7.2.3 Subject population

Subjects who met the following inclusion/exclusion criteria were
eligible for enrollment in the study.

Inclusion criteria:

●

Provision of written informed consent and/or authorization for
access to and use of health information by subjects or appropriate
legal guardians as required by an institution’s Investigational
Review Board, Medical Ethics Board, or Research Ethics Board

●

Availability of implant, follow-up, and product-related event data

●

Implanted with a Model 4965 lead actively being used for pacing
or sensing application

Exclusion criteria:

●

Subjects who received an implant at a non-participating center and
data cannot be confirmed within 30 days after implant

●

Subjects inaccessible for follow-up study center

●

Subjects with exclusion criteria required by local law (EMEA only)

Table 7 summarizes Model 4965 Post Approval Study subject
demographics.

Table 7. Subject demographics

Demographic cate­gory Data type Statistics

Age N 73

MIN 19.2

15

Table 7. Subject demographics (continued)

Demographic cate­gory Data type Statistics

MAX 86.8

MEAN 61.8

STD 15.5

Gender Female 29 (39.7%)

Male 44 (60.3%)

7.2.4 Model 4965 Post Approval Study Limitations

The Model 4965 Lead is approved for use in both pediatric and adult
patients. However, the PMA Approval Letter (dated 06 SEP 1996)
required that a post approval study of fifty (50) adults subject be
conducted as a Condition of Product Approval. Therefore, lead survival
reported in the post approval study is not inclusive of pediatric patients.

A limitation of this study was the prolonged study duration due to the
low annual implant rates for epicardial leads in adults. Seventy-three
(73) patients were enrolled into the Model 4965 post approval study
from 27 DEC 1996 until 27 SEP 2010, for a total duration of nearly
fourteen (14) years.

Both prospective and retrospective (> 6 months post-implant)
enrollment was allowed, with thirty-six (36 = 49.3%) patients enrolled
into the study retrospectively.

Due to the post approval study limitations, a Literature Summary is
provided in Section 7.2.8, “Literature summary”, page 20 .

7.2.5 Results

The total number of Model 4965 leads implanted in the 73 study
subjects was 98, which contributed a total device experience of 2711
months (Table 8). Device experience was calculated from implant date
to exit date, death date, maximum follow-up date, or date of a lead
event if the lead was reported to have chronic lead-related
observations or complications. The range of device experience was
from 0 to 146.73 months, with a median of 16.56 months.

Table 8. Summary of device experience (months)

N 98

Mean 27.66

Standard deviation 32.19

Minimum 0

25% Percentile 0.46

Median 16.56

75% Percentile 44.22

Maximum 146.73

Total device experience 2711.00

16

A survival curve and 95% confidence bound at the terminus of the

Years after Implant

Lead 4965

Survival Probability (%)

%

n

# Failed

survival curve are presented below. The lead-related complication free
survival probability at one-year was 98.8%, with 95% CI (91.8%,

99.8%). All 98 enrolled Model 4965 leads were included in the survival
analysis.

Figure 9. Survival curve and 95% confidence bound

7.2.6 Model 4965 Performance events summary

There were eight lead observations and two lead-related
complications reported from the 98 leads (in 73 subjects). The two lead
complications were reviewed and adjudicated by the Medtronic SLS
Technical Review Committee. Table 9 summarizes the Model 4965
lead complications and Table 10 summarizes the Model 4965 lead
observations.

17

Table 9. Summary of Model 4965 Lead related complications

Implant
date

01 FEB
2002

21 OCT
2003

Event
onset
date

27 MAR
2002

01 MAY
2006

Days
post­implant

Event
classifi­cation

54 Failure to

capture/L
oss of
capture

923 Lead con-

ductor
fracture

Investi­gator
classifi­cation

Failure to
capture,
Intermit­tent

Failure to
capture,
sustained;
abnormal
pacing
impe­dance or
significant
decrease
/increase
since
implant;
lead con­ductor
fracture
observed
radio­graphi­cally

All clini­cal
actions
taken

Lead
polarity
reprog­rammed

Lead elec­tronically
aban­doned

Table 10. Summary of Model 4965 Lead observations

Implant
date

29 SEP

a

1997

Event onset
date

31 AUG
2000

Days post­implant

classifica­tion

1067 New system

because of
pacemaker
syndrome

Investigator

07 APR

a

1998

02 MAY
2000

756 Not available Lead explan-

28 SEP 1998 03 JAN 2001 828 Late local

ventricular
sensing

19 JUL 1999 26 JUL 1999 7 Upgrade to

dual cham­ber

All clinical
actions
taken

Lead surgi­cally aban­doned/cap­ped

ted/replaced

Lead elec­tronically
abandoned

Lead surgi­cally aban­doned/cap­ped

18

Table 10. Summary of Model 4965 Lead observations (continued)

Implant
date

02 JUL 1999 07 APR 2000 280 Ventricular

25 FEB 2000 01 MAR

a

Subject implanted with two Model 4965 leads. Both leads were explanted with
no further information provided from the study center.

Event onset
date

2000

Days post­implant

5 Threshold

Investigator
classifica­tion

lead prob­lem.
Switched to
endocardial
system.

rise, sudden

All clinical
actions
taken

Lead surgi­cally aban­doned/cap­ped

Lead surgi­cally aban­doned/cap­ped

Eighteen deaths were reported in the Model 4965 Lead Study. All
subject deaths were reviewed by the study Event Adjudication
Committee (EAC) and none were determined to be lead-related. The
EAC was comprised of four physicians not affiliated with the System
Longevity Study.

7.2.7 Post Approval Clinical Study conclusion

The survival probability of the Model 4965 lead was 98.8% at one year
post-implant and was 95.9% at 69 months post-implant in patients who
were >19 years of age at the time of implant.

The Model 4965 Post Approval Study enrolled subjects over the
course of 13 years, thus capturing changes in product utilization and
implant technique and therefore representing the survival of the Model
4965 lead over time. However, the study cohort for the Model 4965
Post Approval Study was limited to subjects >19 years of age at the
time of implant, limiting the survival analysis of the Model 4965 lead in
a pediatric population.

19

7.2.8 Literature summary

Medtronic Model 4965 and 4968 epicardial leads, along with epicardial
leads manufactured by other companies, were studied as permanent
epicardial pacing leads in children reported by Thomson (2004)3. In
contrast to the Model 4965 PAS where only adult patients (>19 years
at implant) were included, the Thomson study only enrolled pediatric
patients under 18 years of age (median 1.9 years). It was observed
that the lead survival was 92%, 86% and 76% at 1, 2, and 5 years for
steroid eluting epicardial leads. The causes of lead failures were
increasing pacing thresholds, lead fracture, suboptimal pacing, lead
displacement and infection. Thomson’s study observed a significant
effect of ’decade of implant’ which includes a team approach: follow-up
by a consultant electrophysiologist in a dedicated clinic and implant by
an experienced surgeon with in-theater system interrogation. The
author commented that implanters’ technique and experience
contributed to lead survival. Similar lead survival rates were reported
from a single center study on 321 Model 4965 leads in 138 pediatric
patients by Ector (2006)4. The study collected data over 13 years
(1992–2005). The 1, 3, and 5 years lead survival was 91%, 85% and
71% respectively. The percent of patients without serious adverse
events at 1, 3 and 5 years was 97%, 91% and 85% respectively.

Since Cardiac Resynchronization Therapy (CRT) was demonstrated
to improve patient heart failure conditions, epicardial leads had
become a viable option for pacing the LV chamber. It was observed
that Model 4965 leads were placed in RA, RV and/or LV chambers.
Medtronic Model 4965 and 4968 leads were studied by Mair &
Sachweh, et al5 for biventricular pacing. A total of 86 patients were
enrolled in this study for either coronary sinus or epicardial lead
implants. While this study focused on the technical aspects of
implantation of LV leads for biventricular pacing, and no lead survival
information was presented, the study did demonstrate that LV lead
sense performance was similar between the CS and epicardial leads.
The chronic pacing thresholds were lower for patients with epicardial
leads. Post-implant, the epicardial leads had significantly less LV-lead
related complications compared to CS leads.

3

John D.R. Thomson, Michael E. Blackburn, et al, Pacing Activity, Patients and Lead
Survival Over 20 years of Permanent Epicardial pacing in Children, The Annals of
Thoracic Surgery 2004; 77:1366–1370.

4

B. Ector, R. Willems, et al, Epicardial pacing: A Single-centre Study on 321 leads
in 138 Patients, Acta Cardio 2006; 61(3): 343–351.

5

Helmut Mair, Joerg Sachweh, et al., Surgical Epicardial Left Ventricular Lead
versus Coronary Sinus Lead Placement in Biventricular Pacing, European Journal
of Cardio-thoracic Surgery 27 (2005) 235-242.

20

A combination of Medtronic, St. Jude, and Guidant leads and devices
were studied in Ailawadi’s analysis6. Lead models were not specified
in the published article. A total of 45 patients who had failed coronary
sinus (CS) lead placement were surgically implanted with epicardial
leads. Propensity matching was used to select 135 patients with
successful LV lead implants via CS. The study concluded that
improvements of patient heart failure condition (re-admission for CHF,
EF and NYHA) were observed for patients who received either CS or
epicardial LV leads. The mean percentage of time patients had
biventricular pacing was not different (95%, vs. 93%, p=0.48). No lead
survival information was presented in Ailawadi’s analysis.

Fortescue, et al7 retrospectively compared steroid-eluting epicardial
leads to thin transvenous pacemaker leads in pediatric and congenital
heart disease patients. A total of 256 steroid-eluting epicardial leads
(in 184 patients) were implanted in patients who were 0.0 to 54.6 years
(median 6.3 years). Of those, 67 were Model 4965 unipolar
steroid-eluting epicardial leads. Lead failures for the steroid-eluting
epicardial leads included chronic dislodgement, fracture, high
thresholds, insulation break, infection, and other. Freedom from lead
failure for the steroid-eluting epicardial leads at 1, 3 and 5 years was
96%, 92% and 58%, respectively. There was no statistical difference
when comparing the steroid-eluting epicardial and transvenous
freedom from lead failure probabilities.

A recent publication by Kubus, et al8 evaluated clinical outcome for
permanent epicardial pacing in children. One hundred and nineteen
patients (median age 1.8 years, inter-quartile range 2.9 – 11.1 years)
were implanted with 242 epicardial leads; 161 of the leads were Model
4968 bipolar steroid-eluting leads and 35 of the leads were Model 4965
unipolar steroid-eluting leads. The steroid-eluting leads showed a
significantly higher freedom from exit block (95.3 vs 76.2%
(non-steroid leads) at 5 years p <0.001). The authors concluded that
steroid-eluting epicardial leads may be used on an individual basis to
effectively delay transvenous pacing and to protect venous access to
the heart for further decades of cardiac pacing. The difference in
epicardial vs transvenous lead survival has become marginal with the
advent of steroid-eluting epicardial leads.

6

Gorav Ailawadi, Damien LaPar, et al., Surgically Placed Left Ventricular Leads

Provides Similar Outcome to Percutaneous Leads in Patients with Failed Coronary
Sinus Lead Placement, Heart Rhythm, Vol 7, No5, May 2010.

7

Elizabeth B. Fortescue, Charles I. Berul, Frank Cecchin, Edward P. Walsh, John
K. Triedman, and Mark E. Alexander, Comparison of Modern Steroid-Eluting

Epicardial and Thin Transvenous Pacemaker Leads in Pediatric and Congenital
Heart Disease Patients, Journal of Interventional Cardiac Electrophysiology 14,

27-36, 2005

8

Petr Kubus, Ondrej Materna, Roman A. Gebauer, Tomas Matejka, Tomas Tlaskal,
and Jan Janousek, Permanent epicardial pacing in children: long-term results and

factors modifying outcome, Europace (2011) in press 10.1093/europace/eur327

21

Table 11. Summary of Medtronic Model 4965 Lead Survival Results

Study Details

Medtronic Model
4965 Clinical
Study

Medtronic Model
4965 Post Appro­val Study

John D.R. Thom­son, Michael E.
Blackburn, et
al, Pacing Activity,

Patients and Lead
Survival Over 20
years of Perma­nent Epicardial
pacing in Children,

The Annals of
Thoracic Surgery
2004;
77:1366-1370

B. Ector, R. Wil­lems, et al, Epicar-

dial pacing: A Sin­gle-centre Study
on 321 leads in
138 Patients, Acta

Cardio 2006;
61(3): 343-351

Study Design
Summary:

Population: Pediatric and adult

Device: Medtronic Model 4965 Leads

Study Size: 661 epicardial pacing leads in 381

Lead Survival
Results:

Study Design
Summary:

Population: Adult (> 19 at implant)

Device: Medtronic Model 4965 Leads

Study Size: 98 epicardial pacing leads in 73

Lead Survival
Results:

Study Design
Summary:

Population: Pediatric

Devices: Medtronic Model 4965 Leads,

Study Size: 96 epicardial pacing leads in 59

Lead Survival
Results:

Study Design
Summary:

Population: Pediatric and adult

Devices: Medtronic Model 4965 Leads

Study Size: 321 leads epicardial in 138 patients;

Lead Survival
Results:

Prospective, multi-site, investiga­tional study

patients: median age at implant for
pediatric patients = 2.3 years;
median age at implant for adult
patients = 34.3 years.

Survival in pediatric patients:
1 year 93.6%

Prospective, multi-site, non-random­ized study

patients: mean age at implant = 61.8
years

Lead related complication free rate:
1 year 98.8%
2 years 98.8%
5 years 95.9%

Prospective, single site,
non-randomized

Medtronic Model 4968 Leads, plus
epicardial leads manufactured by
other companies

pediatric patients: median age at
implant = 1.9 years

Survival for steroid eluting epicardial
leads:
1 year 92%
2 years 86%
5 years 76%

Prospective, single site,
non-randomized

mean age = 28.5 years

Freedom from lead failure:
1 year 91%
3 years 85%
5 years 71%

22

Table 11. Summary of Medtronic Model 4965 Lead Survival Results
(continued)

Study Details

Elizabeth B. For­tescue, Charles I.
Berul, Frank Cec­chin, Edward P.
Walsh, John K.
Triedman, and
Mark E.
Alexander, Com-

parison of Modern
Steroid-Eluting
Epicardial and
Thin Transvenous
Pacemaker Leads
in Pediatric and
Congenital Heart
Disease Patients,

Journal of Inter­ventional Cardiac
Electrophysiology
14, 27-36, 2005

Study Design
Summary:

Population: Pediatric and adult

Devices: Medtronic Model 4965 Leads,

Study Size: 256 epicardial leads; median age at

Lead Survival
Results:

Retrospective, single site,
non-randomized

Medtronic Model 4968 Leads, plus
epicardial leads manufactured by
other companies

implant 6.3 years

Freedom from lead fracture for ste­roid eluting epicardial leads:
1 year 96%
3 years 92%
5 years 58%

Surgical lead placement requires a different implant technique
compared to transvenous implants. Three of the published studies
referenced center-to-center or implanter experience differences. The
event classification methods used for these published studies can be
different comparing to the Model 4965 PAS. Nonetheless, there is no
evidence to expect a much lower lead survival probability
post-operatively.

In summary, epicardial leads, specifically Model 4965 and Model
4968, are valuable choices for pediatric patients to avoid long-term
vascular injury and for patients with unsuccessful transvenous lead
implants. Technique and experiences are critical to minimize lead
implant procedures related complications.

8 Directions for use

8.1 Attaching the electrode to the epicardium

The attachment site should be an avascular area free of infarcts, fat,
or fibrosis. If bipolar pacing is indicated, a separate electrode may be
installed adjacent to the first with a minimum of 1.0 cm space between

9

them.

A variety of surgical approaches can be used, including subxiphoid,
left thoracotomy, median sternotomy, transxiphoid, and
trasmediastinal (Figure 10); however, clinical trials have shown the
techniques to have statistically different rates of success as shown in
Table 4.

9

Refer to the Adverse events section of this manual.

23

Figure 10. Surgical approaches

1 Medial sternotomy
2 Left thoracotomy

3 Subxiphoid

The recommended techniques and guidelines are detailed following
this paragraph.

Surgical technique for the subxiphoid approach

1. Maximize exposure to the epicardial surface.
Note: The pericardial sac should be tied back to maximize
exposure to the myocardium.

2. Before implantation, the epicardial lead can be used as a mapping
probe by resting the electrode against the epicardium. Stimulation
thresholds and sensing signal amplitudes can be measured at
various sites in order to locate a suitable attachment site
(Figure 11). Each time the electrode touches the epicardium
some steroid elutes. Therefore when determining the best
electrical placement for the electrode, move the electrode as
minimally as possible.

Figure 11. Exposing the epicardial surface and using the lead as a mapping probe.

1 Xiphoid
2 Heart outline
3 Suture

24

4 Gently grasp the lead directly

over the suture groove

5 Base of the heart

3. Once an optimal electrode position is confirmed for either the
atrium or ventricle, stable fixation through proper suturing of the
electrodes is critical for maintaining good chronic electrode
performance. Suture holes are provided as guides and allow for
a variety of suturing options (Figure 12).

Figure 12. The Model 4965 suture pads have 2 suture holes for attachment to the epicardium. The top and side views of the electrodes illustrate the suture holes and grooves that allow many suturing possibilities.

The recommended suturing technique is the double needle
approach, using non-absorbable sutures, to suture through the
epicardium (Figure 13).

Figure 13. Using a double needle approach

Insert both needles through the distal suture holes on the
electrode head. Suture through the epicardium and tie
(Figure 14).

Figure 14. Suturing through the epicardium and tying

25

Proper suturing of the electrode is critical for maintaining good
chronic electrical performance (Figure 15). Loosely attached
electrodes might allow some movement, irritating the epicardium,
and eventually resulting in elevated thresholds.

Figure 15. Proper suturing of the electrode

1 Recommended
2 Not recommended

To avoid causing trauma to tissue near the electrodes, which may
result in higher thresholds, suture the electrodes perpendicular to
the heart surface (Figure 16).

Figure 16. Acceptable electrode suturing

1 Recommended
2 Not recommended

Note: A suture should not pass under the electrode.
To avoid buckling of the electrode, tie the suture securely, without
placing undue tension on the lead (Figure 17).

Figure 17. Acceptable suture tying

1 Recommended
2 Not recommended

4. Suture through the proximal groove to assure a stable 3 point
fixation (Figure 18).

26

Figure 18. Suturing through the proximal groove

5. Confirm the electrical measurement. See Section 8.2, “Taking
electrical measurements”, page 28.

Guidelines for a left thoracotomy approach

1. Use the suturing technique described in the previous section:
“Surgical technique for the subxiphoid approach.”

2. Leave a moderate amount of the lead on both sides of the thoracic
exit point to prevent stretching of the lead body (Figure 19).

Figure 19. Using a left thoracotomy approach

3. Leaving the lead body deep in the abdominal musculature, exit
the thorax through the subxiphoid space. Exit the thorax at an
angle, not parallel, to the midsagittal plane to reduce acute
bending of the lead at the subcostal border. Tunneling the lead
laterally or exiting the thorax near the subxiphoid area may reduce
the potential for conductor coil fracture (Figure 20).

27

Figure 20. Tunneling the lead

1 Costal and subcostal areas to avoid while tunneling
2 Approximate lower costal region

8.2 Taking electrical measurements

Low stimulation thresholds and adequate sensing of intracardiac
signal amplitudes indicate satisfactory lead placement. Medtronic
recommends using a voltage source such as a pacing system analyzer
for obtaining electrical measurements.

A low stimulation threshold provides for a desirable safety margin,
allowing for a possible rise in thresholds that may occur within 2 months
following implantation.

Adequate sensing amplitudes ensure that the lead is properly sensing
intrinsic cardiac signals. Minimum signal requirements depend on the
pulse generator’s sensitivity capabilities. Acceptable acute signal
amplitudes for the lead must be greater than the minimum pulse
generator sensing capabilities including an adequate safety margin to
account for lead maturity.

Table 12. Recommended electrical measurements at implant

Using a pacing sys­tems analyzer

Ventricle Atrium Ventricle Atrium

Maximum acute stimula­tion thresholds

Minimum acute sensing
amplitudes

a

At pulse duration setting of 0.5 ms.

a

1.5 V

4.0 mV 2.0 mV

a

1.5 V

Using an external
pulse generator

a

3.0 mA 3.0 mA

Initial electrical measurements may deviate from the
recommendations because of acute cellular trauma. If this occurs, wait
5 to 15 minutes and repeat the testing procedure. Values may vary
depending on the lead type, pulse generator settings, cardiac tissue
condition, and drug interactions.

28

If electrical measurements do not stabilize to acceptable levels, it may
be necessary to reposition the lead and to repeat the testing
procedure.

For more information on obtaining electrical measurements, consult
the technical manual supplied with the testing device.

8.3 Connecting the lead to the pulse generator

If a separate pocket is created for the pulse generator, the lead should
be passed within muscle layers to the pocket while avoiding sharp
angle bends to the lead body. Attach the connector end of the lead to
the tunneler and pass the tunneler to the pocket incision. When
removing the lead from the tunneler, hold the lead connector tightly
near the pin and gently pull and twist off.

Connect the lead to the pulse generator according to the instructions
in the pulse generator manual. Do not use excessive force to connect
the lead.

The connector on the Model 4965 is a unipolar connector (IS-1 UNI).
IS-1 Unipolar (UNI) and IS-1 Bipolar (BI) leads always have the label
identification “IS-1 UNI” or “IS-1 BI” on the connector.

Caution: To prevent undesirable twisting of the lead body, wrap the
excess lead length loosely under the pulse generator and place both
into the subcutaneous pocket (Figure 21).

Figure 21. While rotating the pulse generator, loosely wrap the excess lead length and place it under the pulse generator.

Caution: When placing the pulse generator and lead(s) into the
subcutaneous pocket:

●

Do not coil the lead. Coiling the lead can twist the lead body and
may result in lead dislodgment (Figure 22).

●

Do not grip the lead or pulse generator with surgical instruments.

Figure 22. Do not coil the lead body.

After implantation, monitor the patient’s electrocardiogram
continuously during the immediate postoperative period. If a lead
dislodges, it usually occurs during the immediate postoperative period.

29

8.4 Using a lead end cap

Use a lead end cap to seal off the connector pin (Figure 23) if the lead
is being reserved for pulse generator connection at a future date, or if
the lead has been abandoned, (i.e., any leads not explanted but not
connected to the pulse generator).

Insert the end cap over the lead connector pin so that the sealing rings
on the lead are fully covered. Only sterile water may be used to facilitate
this application. No adhesives are necessary. Tie a non-absorbable,
synthetic ligature in the end cap’s groove.

Figure 23. Using the lead end cap

Caution: Do not secure the ligature so tightly that it damages the end

cap and the lead.

The end cap can be removed a later date without damaging the lead.

9 Detailed device description

9.1 Specifications (nominal)

Parameter Model 4965

Type Unipolar

Chamber Ventricle or atrium

Fixation Sutures

Length 15–110 cm (5.91 to 43.31 in)

Connector IS-1 UNI

Materials Conductor: MP35N

Insulation: Treated silicone rubber

Electrode: Platinum alloy

Connector pin: Stainless steel

Connector ring: Titanium

Tip electrode
configuration

Electrode sur­face area

30

Platinized, porous, steroid eluting

2

14.0 mm

Parameter Model 4965

Unipolar resist­ance

Steroid Dexamethasone sodium phos-

Amount of steroid 1.0 mg maximum

Steroid binder Silicone rubber

38 Ω (50 cm) (19.70 in)

phate

9.2 Specifications drawing (nominal)

Figure 24.

1 9.7 mm (0.382 in)
2 7.6 mm (0.299 in)
3 1.0 mm (0.040 in)
4 Electrode surface area anode:

2

14 mm

5 Lead length: 15 to 110 cm (5.91

to 43.31 in)
6 3.2 mm (0.126 in)
7 1.6 mm (0.063 in)

31

10 Service

Medtronic employs highly trained representatives and engineers
located throughout the world to serve you and, upon request, to
provide training to qualified hospital personnel in the use of Medtronic
products. Medtronic also maintains a professional staff to provide
technical consultation to product users. For more information, contact
your local Medtronic representative, or call or write Medtronic at the
appropriate telephone number or address listed on the back cover.

11 Medtronic warranty

For complete warranty information, see the accompanying warranty
document.

32

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*M950198A001*

Medtronic, Inc.
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USA
www.medtronic.com
Tel. [phone]
Fax [phone]

Medtronic USA, Inc.

Toll-free in the USA (24-hour
technical consultation for
physicians and medical
professionals)
Bradycardia: [phone]
Tachycardia: [phone]

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Representative

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Technical manuals:
www.medtronic.com/manuals

© Medtronic, Inc. 2012
M950198A001C
2012-12-11