Medtronic 6947M49 Technical Manual

SPRINT QUATTRO SECURE® 6947M DXAC/DSP

Dexamethasone acetate and dexamethasone sodium phosphate steroid eluting, quadripolar, screw-in,
ventricular lead with RV/SVC defibrillation coil electrodes

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.

AccuRead, Medtronic, Sprint Quattro, Sprint Quattro Secure, Tensi-Lock

Contents

1 Device description 3
2 Drug component description 3
3 Indications 4
4 Contraindications 4
5 Warnings and precautions 4
6 Adverse events 5
7 Drug information 6
8 Directions for use 7

9 Specifications (nominal) 12
10 Medtronic warranty 14
11 Service 14
12 Explanation of symbols on package labeling 14

1 Device description

The Medtronic Sprint Quattro Secure Model 6947M lead is a
steroid-eluting, quadripolar, screw-in, ventricular lead with right
ventricular (RV) and superior vena cava (SVC) defibrillation coil
electrodes. This lead is designed for pacing, sensing,
cardioversion, and defibrillation therapies.

The lead features an extendable and retractable helix electrode,
silicone insulation, and parallel conductors. The four electrodes
of the lead are the helix, ring, RV coil, and SVC coil. The lead also
features Tensi-Lock1 and silicone-backfilled defibrillation coils.

The DF4-LLHH2 four-pole HV inline connector on the lead
facilitates device connection during implant. The DF4 connector
pin has a color band indicator that may be used to visually confirm
proper connection to the device.

The RV and SVC coils deliver cardioversion and defibrillation
therapies. Pacing and sensing occur between the helix and
ring electrodes. An AccuRead analyzer cable interface tool (ACI
tool) is attached to the lead to facilitate accurate electrical
measurements during implant.

The helix electrode can be actively fixed into the endocardium.
The helix electrode can be extended or retracted by rotating the
DF4 connector pin with one of the purple fixation tools included
in the package.

The distal tip contains a nominal dosage of 685 µg of
dexamethasone acetate and 59 µg of dexamethasone sodium
phosphate. Upon exposure to body fluids, the steroids elute from
the lead tip. The steroids are known to suppress the inflammatory
response that is believed to cause threshold rises typically
associated with implanted pacing electrodes.

1.1 Package contents

Leads and accessories are supplied sterile. Each package
contains the following items:

●

1 lead with a radiopaque anchoring sleeve3, stylet, and
AccuRead tool

●

2 purple fixation tools

●

1 purple stylet guide

●

1 slit anchoring sleeve

●

1 vein lifter

●

extra stylets

●

product literature

1.2 Accessory descriptions

AccuRead analyzer cable interface tool – The AccuRead tool

facilitates accurate electrical measurements during implant and
prevents possible connector damage.

Anchoring sleeve – An anchoring sleeve secures the lead to
prevent it from moving and protects the lead insulation and
conductors from damage caused by tight sutures.

Purple fixation tool – The purple fixation tool facilitates
connector pin rotation.

Purple stylet guide – A stylet guide facilitates stylet insertion into
the lead.

Slit anchoring sleeve – A slit anchoring sleeve secures excess
lead length in the device pocket.

Stylet – A stylet provides additional stiffness and controlled
flexibility for maneuvering the lead into position. Each stylet knob
is labeled with the stylet diameter and corresponding lead length.

Vein lifter – A vein lifter facilitates lead insertion into a vein.

2 Drug component description

The active ingredients in the Model 6947M lead are
dexamethasone acetate [21-(acetyloxy)-9-fluoro-11β,
17-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione] and
dexamethasone sodium phosphate [9-fluoro-11β,
17-dihydroxy-16α-methyl-21-(phosphonooxy)
pregna-1,4-diene-3,20-diene-3,20-dione disodium salt]. The
structural formula for these steroids is shown in the following
figures.

Dexamethasone acetate is a white to practically white, odorless
powder. It is a practically insoluble ester of dexamethasone, a
synthetic adrenocortical steroid.

1

Tensi-Lock is an exclusive Medtronic design feature that utilizes lead body cables to act like a built-in locking stylet and add tensile strength to the lead.

2

DF4-LLHH refers to the International Connector Standard ISO 27186:2010, where the lead connector contacts are defined as low voltage (L) or high voltage (H).

3

Two radiopaque anchoring sleeves are provided on leads that are 85 cm or longer.

3

Figure 1. Structural formula for dexamethasone acetate (DXAC) ­C24H31FO

6

Dexamethasone sodium phosphate (DSP) is an inorganic ester
of dexamethasone, a synthetic adrenocortical steroid.
Dexamethosone sodium phosphate is a white or slightly yellow
crystalline powder. It is freely soluble in water and is very
hygroscopic.

Figure 2. Structural formula for dexamethasone sodium
phosphate (DSP) - C22H28FNa2O8P

The maximum dosage of dexamethasone acetate and
dexamethasone sodium phosphate is less than 1.0 mg per lead.

3 Indications

The lead is intended for single, long-term use in the right ventricle.

This lead has application for patients for whom implantable
cardioverter defibrillators (ICDs) are indicated.

4 Contraindications

Atrial use – The lead is contraindicated for the sole use of

detection and treatment of atrial arrhythmias.

Ventricular use – The lead is contraindicated for ventricular use
in patients with tricuspid valvular disease or a tricuspid
mechanical heart valve.

Transient ventricular tachyarrhythmias – The lead is
contraindicated for patients with transient ventricular
tachyarrhythmias due to reversible causes (drug intoxication,
electrolyte imbalance, sepsis, hypoxia) or other factors
(myocardial infarction, electric shock).

Steroid use – The lead is contraindicated in patients for whom a
single dose of 1.0 mg of dexamethasone acetate and
dexamethasone sodium phosphate may be contraindicated.

5 Warnings and precautions

Inspecting the sterile package – Inspect the sterile package

before opening it.

●

If the seal of the package is damaged, contact a Medtronic
representative.

●

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

●

Do not use the product after its expiration date.

Single use – The lead is for single use only.

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.

Connector compatibility – The DF4-LLHH quadripolar
connector port is not compatible with DF-1 or IS-1 leads. A
DF4-LLHH quadripolar lead must be used with this port.

Electrophysiologic testing – Prior to lead implant, it is strongly
recommended that patients undergo a complete cardiac
evaluation, which should include electrophysiologic testing. Also,
electrophysiologic evaluation and testing of the safety and
efficacy of the proposed pacing, cardioversion, or defibrillation
therapies are recommended during and after the implant of the
system.

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

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

●

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 – Handle the lead with care at all times.

●

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 pins.

●

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

4

●

Inserting the lead using a lead introducer that has a
hemostasis valve may require a larger introducer than the size
recommended. To avoid distortion of the coil electrode, do
not withdraw the lead through a hemostasis valve.

●

Do not implant the lead without first verifying the mechanical
functioning of the helix electrode. Refer to Section 8.2,
“Verifying the mechanical functioning of the helix electrode”,
page 7, for complete instructions.

●

Do not rotate the helix electrode after it is fully extended or
fully retracted. Do not exceed the recommended maximum
number of rotations to extend or retract the helix electrode.
Exceeding the maximum number may result in fracture or
distortion of the inner conductor or helix electrode. The
number of rotations required to fully extend or retract the helix
electrode is variable; refer to Section 9 for the recommended
maximum number of rotations.

Handling the stylet – Handle the stylet with care at all times.

●

Do not use a sharp object to impart a curve to the distal end
of the stylet.

●

Do not use excessive force or surgical instruments when
inserting the stylet into the lead.

●

Avoid overbending or kinking the stylet.

●

Use a new stylet when blood or other fluids accumulate on
the stylet. Accumulated blood or other fluids may damage the
lead or cause difficulty in passing the stylet into the lead.

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.

Second anchoring sleeve – Leads that are 85 cm or longer
include 2 anchoring sleeves. Use both anchoring sleeves to
assure adequate fixation.

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.

Magnetic resonance imaging (MRI) – Do not use magnetic
resonance imaging (MRI) on patients who have this device
implanted. MRI can induce currents on implanted leads,

potentially causing tissue damage and the induction of
tachyarrhythmias.

Diathermy – People with metal implants such as pacemakers,
implantable cardioverter defibrillators (ICDs), and accompanying
leads should not receive diathermy treatment. The interaction
between the implant and diathermy can cause tissue damage,
fibrillation, or damage to the device components, which could
result in serious injury, loss of therapy, and/or the need to
reprogram or replace the device.

Chronic repositioning or removal of a screw-in lead –

Proceed with extreme caution if a lead must be removed or
repositioned. Chronic repositioning or removal of screw-in
transvenous leads may not be possible because of blood or
fibrotic tissue development into the helix mechanism on the lead.
In most clinical situations, it is preferable to abandon unused
leads in place. Return all removed leads, unused leads, or lead
sections to Medtronic for analysis.

Note: If a helix does not disengage from the endocardium by
rotating the connector pin, rotating the lead body
counterclockwise may withdraw the helix and decrease the
possibility of damage to cardiovascular structures during
removal.

●

Lead removal may result in avulsion of the endocardium,
valve, or vein.

●

Lead junctions may separate, leaving the lead tip and bare
wire in the heart or vein.

●

Chronic repositioning of a lead may adversely affect the
low-threshold performance of a steroid lead.

●

An abandoned lead should be capped so that the lead does
not transmit electrical signals.

●

Severed leads should have the remaining lead end sealed
and the lead body sutured to adjacent tissue.

AccuRead tool – The AccuRead tool reduces the risk of
connector damage, and reduces the risk of bridging and shorting
that may occur while taking electrical measurements during
implant. The potential for connector damage, bridging, and
shorting is due to variations in analyzer cable terminals, as well
as to the connector ring width and the proximity of the rings on the
DF4 connector.

6 Adverse events

Observed adverse events – The Model 6947 lead was utilized

in a prospective, nonrandomized, multicenter trial to assess the
handling and performance of the lead.

Based upon its similarity to the Model 6947M, the clinical data
from the Model 6947 lead supports the safety and efficacy of the
Model 6947M lead. The Model 6947M lead is equivalent to the
Model 6947 lead except for the connector system. Model 6947
uses the IS-1/DF-14 connector system; Model 6947M uses the
Medtronic DF4-LLHH connector system.

From the 6947 clinical trial, a total of 22 cardiovascular-related
adverse events were reported. Two of the 22 events were

4

DF-1 refers to the International Connector Standard ISO 11318:1993, whereby pulse generators and leads so designated are assured of a basic mechanical fit.

5

ventricular lead-related and both occurred at implant. One event
was a microdislodgement and one was induced VT as a result of
lead manipulation.

Two deaths occurred in this patient group during the follow-up
period. Both deaths were classified as non-sudden cardiac and
were judged to be non-system related by an independent
advisory committee.

Potential adverse events – The potential adverse events
associated with the use of transvenous leads and pacing systems
include, but are not limited to, the following events:

●

acceleration of tachyarrhythmias (caused by device)

●

air embolism

●

bleeding

●

body rejection phenomena, including local tissue reaction

●

cardiac dissection

●

cardiac perforation

●

cardiac tamponade

●

chronic nerve damage

●

constrictive pericarditis

●

death

●

device migration

●

endocarditis

●

erosion

●

excessive fibrotic tissue growth

●

extrusion

●

fibrillation or other arrhythmias

●

fluid accumulation

●

formation of hematomas/seromas or cysts

●

heart block

●

heart wall or vein wall rupture

●

hemothorax

●

infection

●

keloid formation

●

lead abrasion and discontinuity

●

lead migration/dislodgement

●

mortality due to inability to deliver therapy

●

muscle and/or nerve stimulation

●

myocardial damage

●

myocardial irritability

●

myopotential sensing

●

pericardial effusion

●

pericardial rub

●

pneumothorax

●

poor connection of the lead to the device, which may lead to
oversensing, undersensing, or a loss of therapy

●

threshold elevation

●

thrombosis

●

thrombotic embolism

●

tissue necrosis

●

valve damage (particularly in fragile hearts)

●

venous occlusion

●

venous perforation

Other potential adverse events related to the lead include, but are
not limited to, the following conditions:

●

insulation failure

●

lead conductor or electrode fracture

7 Drug information

7.1 Steroid mechanism of action

Steroid suppresses the inflammatory response that is believed to
cause threshold rises typically associated with implanted pacing
electrodes. Dexamethasone sodium phosphate and
dexamethasone acetate are synthetic steroids of the
glucocorticoid family. Glucocorticoids have potent
anti-inflammatory actions via direct and indirect effects on major
inflammatory cells. Glucocorticosteroids bind to a cytoplasmic
glucocorticoid receptor as well as a membrane-bound receptor.
Binding to the cytoplasmic receptor leads to receptor activation
and translocation to the nucleus. The receptor interacts with
specific DNA sequences within the regulatory regions of affected
genes. Thus, glucocorticoids inhibit the production of multiple cell
factors that are critical in generating the inflammatory response.

7.2 Pharmacodynamics of the Model 6947M lead

Pharmacokinetics – The pharmacokinetics (local drug levels

and systemic levels) of dexamethasone acetate (DXAC) and
dexamethasone sodium phosphate (DSP) and their metabolites
following lead implantation were not evaluated in human clinical
trials.

The in-vivo elution profile of a tined pacemaker lead with a DSP
monolithic controlled release device, based upon an assay of
explanted leads, is shown in Mond and Stokes5.

Metabolism – The conversion of DSP to dexamethasone occurs
within minutes; the conversion of DXAC to dexamethasone
occurs within hours. The dexamethasone alcohol
(dexamethasone) is the active glucocorticoid used in Medtronic
leads. Steroid is applied to the tip and eluted through the electrode
tip to the tissue interface where it will be used. Dexamethasone
acetate and Dexamethasone sodium phosphate are hydrolyzed
into dexamethasone, which is readily absorbed by the
surrounding tissue and body fluids. Glucocorticoids, when given
systemically, are eliminated primarily by renal excretion of
inactive metabolites.

Mutagenesis, carcinogenicity and reproductive
toxicology – The mutagenesis, carcinogenicity, and

reproductive toxicity of the Model 6947M lead have not been
evaluated. However, the mutagenesis, carcinogenicity, and
reproductive toxicity of dexamethasone acetate and
dexamethasone sodium phosphate have been evaluated
previously.

Carcinogenesis, mutagenesis, impairment of fertility – No
adequate studies have been conducted in animals to determine
whether corticosteroid have a potential for carcinogenesis (tumor

5

Mond, H. and Stokes, K.B., The Electrode - Tissue Interface: The Revolutionary Role of Steroid Elution, Pacing and Clinical Electrophysiology, Vol. 15, No. 1, pp
95-107

6

initiation or promotion). Dexamethasone was genotoxic in assays
for clastogenicity (including sister chromatid exchange in human
lymphocytes) but not in an assay for mutagenicity in salmonella
(Ames test).

Adrenocorticoids have been reported to increase or decrease the
number and mobility of spermatozoa in some patients.

Pregnancy – Pregnancy category C. Dexamethasone acetate
and Dexamethasone sodium phosphate have been shown to be
teratogenic in many species when given in doses equivalent to
the human dose. There are no adequate and well-controlled
studies in pregnant women. Dexamethasone acetate and
Dexamethasone sodium phosphate should be used during
pregnancy only if the potential benefit justifies the potential risk to
the fetus. Studies in mice, rats, and rabbits have shown that
adrenocorticoids increase the incidence of cleft palate, placental
insufficiency, and spontaneous abortions, and can decrease the
intrauterine growth rate.

Nursing mothers – Systemically administered corticosteroids
appear in human milk and could suppress growth, interfere with
endogenous corticosteroid production, or cause other untoward
effects in nursing infants. Because of the potential for serious
adverse reactions in nursing infants from corticosteroids, a
decision should be made whether to discontinue nursing or to use
a non-steroidal lead, taking into account the importance of the
lead and the drug to the mother.

8 Directions for use

8.1 Opening the package

Use the following steps to open the sterile package and inspect
the lead:

1. Within the sterile field, open the sterile package and remove
the lead and accessories.

2. Inspect the lead. Leads that are shorter than 85 cm should
have 1 anchoring sleeve on the lead body. Leads that are
85 cm or longer should have 2 anchoring sleeves on the lead
body.

8.2 Verifying the mechanical functioning of the helix electrode

Before implant, verify the mechanical functioning of the helix
electrode using the following steps:

1. If needed, slide the stylet guide away from the connector pin,
and then press both legs of the fixation tool together and
place the most distal hole on the DF4 connector pin
(Figure 3).

Figure 3.

Proper surgical procedures and sterile techniques are the
responsibility of the medical professional. The following
procedures are provided for information only. Some implant
techniques vary according to physician preference and the
patient’s anatomy or physical condition. Each physician must
apply the information in these instructions according to
professional medical training and experience.

The implant procedure generally includes the following steps:

●

Opening the package

●

Verifying the mechanical functioning of the helix electrode

●

Inserting the lead

●

Positioning a screw-in ventricular lead

●

Securing the helix electrode into the endocardium

●

Taking electrical measurements and defibrillation efficacy
measurements

●

Anchoring the lead

●

Connecting the lead

●

Placing the device and lead into the pocket

2. Keep the lead body and the DF4 connector sleeve as straight
as possible. Ensure that the stylet is fully inserted, then rotate
the fixation tool clockwise until the helix electrode is fully
extended (Figure 4). When the helix electrode is fully
extended, approximately 1.5 to 2 helix coils are exposed.

Figure 4.

Caution: Do not severely bend the DF4 connector sleeve or

the lead body while extending the helix electrode.
Caution: Overrotating the connector pin after the helix
electrode is fully extended or fully retracted may damage the
lead.

7

The number of rotations required to extend or retract the helix

1

electrode increases proportionately with the length of the
lead. Additional curvatures made to the stylet may increase
the number of rotations needed to extend or retract the helix
electrode. Rotation of the fixation tool should be stopped
once full helix retraction is visually verified. Overretraction of
the helix may result in the inability to extend the helix. If the
helix is unable to extend, use a new lead.
Note: To determine the number of rotations applied to the
lead, count the number of rotations of the fixation tool. See
Section 9 for the maximum number of rotations to extend or
retract the helix electrode.
During the initial helix electrode extension, the helix
electrode may extend suddenly due to accumulated torque
in the lead, or the helix electrode may require additional turns
for extension.

3. Disconnect the fixation tool from the connector pin and
release the proximal end of the lead body. Allow several
seconds for relief of the residual torque in the lead.

4. After allowing for relief of the residual torque, reattach the
fixation tool and rotate it counterclockwise until the helix
electrode tip is retracted into the sheath.

8.3 Inserting the lead

Caution: Use care when handling the lead during insertion.

●

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

●

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

Insert the lead using the following techniques:

1. Select a site for lead insertion. The lead may be inserted by
venotomy through several different venous routes, including
the right or left cephalic vein, the subclavian vein, or the
external or internal jugular vein. Use the cephalic vein
whenever possible to avoid lead damage in the first rib or
clavicular (thoracic inlet) space.

Cautions:

●

Certain anatomical abnormalities, such as thoracic
outlet syndrome, may also precipitate pinching and
subsequent fracture of the lead.

●

When using a subclavian approach, avoid techniques
that may damage the lead.

●

Place the insertion site as far lateral as possible to avoid
clamping the lead body between the clavicle and the first
rib (Figure 5).

Figure 5.

●

Do not force the lead if significant resistance is
encountered during lead passage.

●

Do not use techniques such as adjusting the patient’s
posture to facilitate lead passage. If resistance is
encountered, it is recommended that an alternate
venous entry site be used.

2. Insert the tapered end of a vein lifter into the incised vein and
gently push the lead tip underneath and into the vein
(Figure 6).
Note: A percutaneous lead introducer (PLI) kit may be used
to facilitate insertion. If an introducer is used, it should be at
least 3.0 mm (9 French). Refer to the technical manual
packaged with an appropriate percutaneous lead introducer
for further instructions.

Figure 6.

3. Advance the lead into the right atrium using a straight stylet
to facilitate movement through the veins.

8.4 Positioning a screw-in ventricular lead

Caution: Use care when handling the lead during positioning.

●

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

●

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

Use the following steps to position the lead:

1. After the lead tip is passed into the atrium, advance the lead
through the tricuspid valve. Replace the straight stylet with
a gently curved stylet to add control when maneuvering the
lead through the tricuspid valve.
Caution: Do not use a sharp object to impart a curve to the
distal end of the stylet. Imparting a curve to the stylet can be
accomplished with a smooth-surface, sterile instrument
(Figure 7).

Figure 7.

1 Suggested entry site

8

Note: When you pass the lead tip through the tricuspid valve
or chordae tendineae, it may be difficult due to the flexible
nature of the lead body. Rotate the lead body as the tip
passes through the valve to facilitate passage.

2. After the lead tip is in the ventricle, the curved stylet may be

1

2

1 2

replaced with a straight stylet. Withdraw the stylet slightly, to
avoid using excessive tip force while achieving final
electrode position. Avoid known infarcted or thin wall areas
to minimize the occurrence of perforation.

3. Proper positioning of the helix electrode is essential for
stable endocardial pacing. A satisfactory position usually is
achieved when the lead tip points straight toward the apex,
or when the distal end dips or bends slightly. Use fluoroscopy
(lateral position) to ensure that the tip is not in a retrograde
position or lodged in the coronary sinus.
Note: With the helix electrode retracted, the distal end of the
lead may be used to map a desirable site for electrode
fixation. Mapping may reduce the need to repeatedly extend
and fixate the helix electrode.

4. After placing the lead in a satisfactory position, extend the
helix electrode by following the procedure in Section 8.5.

8.5 Securing the helix electrode into the endocardium

Secure the helix electrode using the following techniques:

1. If needed, slide the stylet guide away from the connector pin,
and then press both legs of the fixation tool together and
place the most distal hole on the DF4 connector pin
(Figure 3).

2. Ensure that the stylet is inserted into the lead, and then press
the lead tip against the endocardium by gently pushing the
stylet and lead at the vein entry site.

3. Rotate the fixation tool clockwise until the helix electrode is
fully extended (see Figure 4).
Caution: Do not severely bend the DF4 connector sleeve or
the lead body while extending the helix electrode.
Use fluoroscopy to verify helix electrode exposure. Both a
visual and fluoroscopic view of a fully retracted helix
electrode is shown in Figure 8. Both a visual and fluoroscopic
view of a fully extended helix electrode is shown in
Figure 9. Closing of the space between the crimp sleeve and
the indicator ring implies complete exposure of the helix
electrode.

Figure 8.

1 Crimp sleeve
2 Indicator ring

Figure 9.

1 Crimp sleeve
2 Indicator ring

Cautions:

●

The number of rotations required to fully extend or retract
the helix electrode is variable. Rotation should be
stopped once full helix extension or retraction is verified
with fluoroscopy as shown in Figure 8 and Figure 9.
Overretraction of the helix, during initial implant or
subsequent repositioning, may result in the inability to
extend the helix. If the helix is unable to extend, replace
with a new lead.

●

Do not exceed the recommended maximum number of
rotations to extend or retract the helix electrode.
Exceeding the maximum number may result in fracture
or distortion of the inner conductor or helix electrode.
Refer to Section 9 for the recommended maximum
number of rotations.

●

Prolonged implant procedures or multiple repositionings
may allow blood or body fluids to build up on the helix
electrode mechanism. This may result in an increased
number of rotations required to extend or retract the
helix electrode.

4. Remove the fixation tool from the DF4 connector pin, and
release the proximal end of the lead body. Allow several
seconds for relief of the residual torque in the lead.

5. To assure helix electrode fixation, leave the stylet in place,
hold the lead by the connector, and carefully rotate the lead
body in 2 clockwise rotations.

6. Partially withdraw the stylet.

7. Obtain electrical measurements to verify satisfactory
placement and electrode fixation. Refer to Section 8.6,
“Taking electrical measurements and defibrillation efficacy
measurements”, page 9.

8. Verify that the lead is affixed. Gently pull back on the lead,
and check for resistance to verify fixation. A properly affixed
helix electrode will remain in position. If the helix electrode
is not properly affixed, the lead tip may become loose in the
right ventricle.

9. If repositioning is required, reattach the fixation tool, and
rotate counterclockwise until the helix electrode is retracted.
Use fluoroscopy to verify withdrawal of the helix electrode
before attempting to reposition.

10. After final positioning, make sure that the stylet and the
fixation tool have been completely removed.

11. Obtain final electrical measurements. Refer to Section 8.6.

8.6 Taking electrical measurements and defibrillation efficacy measurements

Caution: Prior to taking electrical or defibrillation efficacy

measurements, move objects made from conductive materials,
such as guide wires, away from all electrodes. Metal objects, such
as guide wires, can short a lead and an active implantable device,
causing electrical current to bypass the heart and possibly
damage the implantable device and lead.

The ACI tool is used to facilitate accurate electrical
measurements during implant. The lead package will contain one
of two existing ACI tool designs as shown in Figure 10 and
Figure 11. When attaching or removing the ACI tool:

9

1. Be sure to grasp the grooves of the plastic housing (see
Figure 10) and not the metallic contacts.

Figure 10.

2. Grasp the ACI tool in the most convenient location (see
Figure 11).

Figure 11.

Figure 12.

Caution: The AccuRead tool reduces the risk of connector

damage, and reduces the risk of bridging and shorting that may
occur while taking electrical measurements during implant. The
potential for connector damage, bridging, and shorting is due to
variations in analyzer cable terminals, as well as to the connector
ring width and the proximity of the rings on the DF4 connector.

Note: The ACI tool may be removed or attached at any time during
the procedure using the slit on the side of the tool (see Figure 12 or
Figure 13).

1 Removing the ACI tool from the connector pin
2 Removing the ACI tool from the stylet using the slit on the side of the

tool (Do not let go of the ACI tool; the ACI tool can fall off the stylet.)

Figure 13.

1 Removing the ACI tool from the connector pin
2 Removing the ACI tool from the stylet using the slit on the side of the

tool

Use the following steps to take electrical measurements:

1. Ensure that the fixation tool is disconnected from the DF4
connector pin.

2. Ensure that the lead connector is completely inserted into
the ACI tool. The connector pin will be completely accessible
if the ACI tool is properly attached (see Figure 14 or
Figure 15).

10

Figure 14.

Figure 15.

1 When properly attached, all 3 contacts are visible through the ACI

tool openings.

3. Attach a surgical cable to the ACI tool. Line up the cable clips
with the contacts on the ACI tool to ensure that accurate
readings are obtained. (See Figure 22 for specific contacts.)

4. Use a testing device, such as a pacing system analyzer, for
obtaining electrical measurements (see Table 1 for
recommended measurements). For information on the use
of the testing device, consult the product literature for
that device.

5. After the electrical measurements are complete, remove the
surgical cable from the ACI tool before removing the tool from
the lead.

In order to demonstrate reliable defibrillation efficacy, obtain final
defibrillation measurements for the lead system.

Table 1. Recommended measurements at implant (when using a pacing system analyzer)

Measurements
required Acutea lead system

Capture threshold
(at 0.5 ms pulse width)

Pacing impedance 200–1000 Ω 200–1000 Ω

Filtered R-wave
amplitude (during
sinus rhythm)

Slew rate ≥0.75 V/s ≥0.45 V/s

a

<30 days after implant.

b

>30 days after implant.

≤1.0 V ≤3.0 V

≥5 mV ≥3 mV

Chronicb lead sys-

tem

●

Values may vary depending upon lead type, implantable
device settings, cardiac tissue condition, and drug
interactions.

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

In order to keep patient morbidity and mortality to a minimum,
patients should be rescued promptly with an external defibrillator
if the implanted lead system fails to terminate a VF episode. At
least 5 min should elapse between VF inductions.

For more information about obtaining electrical measurements,
consult the product documentation supplied with the testing
device.

8.7 Anchoring the lead

Caution: Use care when anchoring the lead.

●

Use only nonabsorbable sutures to anchor the lead.

●

Do not attempt to remove or cut the anchoring sleeve from
the lead body.

●

During lead anchoring, take care to avoid dislodging the
lead tip.

●

Do not secure sutures so tightly that they damage the vein,
lead, or anchoring sleeve (Figure 16).

●

Do not tie a suture directly to the lead body (Figure 16).

Figure 16.

Use the following steps to anchor the lead using all 3 grooves:

Note: The anchoring sleeves contain a radiopaque substance,
which allows visualization of the anchoring sleeve on a standard
x-ray and may aid in follow-up examinations.

1. Position the distal anchoring sleeve against or near the vein.

2. Secure the anchoring sleeve to the lead body by tying a
suture firmly in each of the 3 grooves (Figure 17).

Figure 17.

If initial electrical measurements deviate from the recommended
values, it may be necessary to repeat the testing procedure 15 min
after final positioning. Initial electrical measurements may deviate
from the recommended values:

●

Initial impedance values may exceed the measuring
capabilities of the testing device, resulting in an error
message.

3. Use at least one additional suture in one of the grooves to
secure the anchoring sleeve and lead body to the fascia.

11

4. A second anchoring sleeve is provided with leads that are
85 cm or longer. For abdominal implants, the redundant lead
body (for example, a curve for strain relief) should be placed
just proximal to the first anchoring sleeve. Then, the second
anchoring sleeve may be lightly sutured to the lead body and
fascia to hold the curve in place. This procedure helps isolate
the vein entry site from tension on the proximal end of the
lead body.

5. A slit anchoring sleeve may be used in the device pocket to
secure excess lead length. First, secure the anchoring
sleeve to the lead body. Then, orient the slit toward the fascia
and secure the anchoring sleeve to the fascia with sutures.

8.8 Connecting the lead

Use the following steps to connect the lead to an implantable
device:

1. Make sure that the stylet and all accessories have been
completely removed. When removing the accessories, grip
the lead firmly just below the AccuRead tool on the connector
to prevent dislodgement.

2. Push the lead or plug into the header block until the color
band on the tip of the lead connector pin is visible in the pin
viewing area (see Figure 18). The color band will be visible
when the lead is fully inserted. Consult the product literature
packaged with the implantable device for instructions on
proper lead connections.

Figure 18. Lead connector pin viewing area

Figure 19.

Use the following steps to place the device and leads into the
pocket:

1. To prevent undesirable twisting of the lead body, rotate the
device to loosely wrap the excess lead length (Figure 20).

Figure 20.

2. Insert the device and leads into the pocket.

3. Before closing the pocket, verify sensing, pacing,
cardioversion, and defibrillation efficacy.

8.10 Post-implant evaluation

1 Lead tip extends past setscrew block; lead connector pin is visible

in pin viewing area (color band may be used to verify full lead

insertion)
2 Setscrew block, located behind grommet
3 Lead

8.9 Placing the device and lead into the pocket

Caution: Use care when placing the device and leads into

the pocket.

●

Ensure that the leads do not leave the device at an acute
angle.

●

Do not grip the lead or device with surgical instruments.

●

Do not coil the lead. Coiling the lead can twist the lead body
and may result in lead dislodgement (Figure 19).

12

After implant, monitor the patient’s electrocardiogram until the
patient is discharged. If a lead dislodges, it usually occurs during
the immediate postoperative period.

Recommendations for verifying proper lead positioning include
x-rays and pacing and sensing thresholds taken at pre-hospital
discharge, 3 months after implant, and every 6 months thereafter.

In the event of a patient death, explant all implanted leads and
devices and return them to Medtronic with a completed Product
Information Report form. Call the appropriate phone number on
the back cover if there are any questions on product handling
procedures.

9 Specifications (nominal)

9.1 Detailed device description

Table 2. Specifications (nominal)

Parameter Model 6947M

Type Quadripolar

Position Right ventricle

Table 2. Specifications (nominal) (continued)

1

234

5

Parameter Model 6947M

Fixation Extendable/retractable helix

Length 45–110 cm

Connector Quadripolar/true

Materials Conductors: MP35N coil

Electrodes (pace, sense): Platinized platinum alloy

DF4 pin and rings: MP35N

Steroid Type: Dexamethasone acetate and

Conductor
resistances

Helix length (extended) 1.8 mm

Diameters Lead body: 2.8 mm

Lead introducer (recommended
size)

Pacing (unipolar): 27.9 Ω (62 cm)

without guide wire: 3.0 mm (9.0 French)

bipolar:

Insulation: Silicone, PTFE, ETFE

Overlay: Polyurethane

Seal Zone: PEEK

RV/SVC coils: Platinum-clad tantalum

DF4 pin: MP35N

Amount: 685 µg of dexamethasone ace-

Steroid binder: Silicone

Pacing (bipolar): 29.3 Ω (62 cm)

Defibrillation: 1.4 Ω (62 cm)

with guide wire: 3.7 mm (11.0 French)

Four-pole inline (DF4-LLHH)

MP35N composite cables

dexamethasone sodium phos­phate

tate
59 µg of dexamethasone sodium
phosphate

Tip: 2.8 mm

Helix: 1.4 mm

Table 3. Maximum number of rotations to extend or retract the helix electrode

Lead length Number of rotations

49 cm 17

55 cm 18

62 cm 20

72 cm 22

97 cm 27

Table 4. Respective electrode distances

Helix electrode to ring electrode 8 mm

Helix electrode to RV coil electrode 12 mm

Helix electrode to SVC coil electrode 180 mm

Figure 21. Model 6947M distal lead components

1 Helix electrode; surface area: 5.7 mm
2 Ring electrode; surface area: 25.2 mm
3 RV coil electrode; length: 57 mm; surface area: 614 mm2; electrical

shadow area: 506 mm

4 SVC coil electrode; length: 80 mm; surface area: 860 mm2; electrical

shadow area: 709 mm

5 Anchoring sleeve; leads 85 cm or longer have 2 anchoring sleeves

2

2

2

2

13

Figure 22. Model 6947M proximal lead components

EC REP

12 Explanation of symbols on package labeling

Refer to the package labels to see which symbols apply to this
product.

Table 5. Explanation of symbols on package labeling

Symbol Explanation

Conformité Européenne (European Conformity).
This symbol means that the device fully complies
with AIMD Directive 90/385/EEC (0123).

Do not use if package is damaged

Do not reuse

Upper limit of temperature

Open here

Sterilized using ethylene oxide

Caution

1 AccuRead tool
2 Connector pin
3 Stylet
4 SVC contact
5 RV contact
6 Ring (+) contact
7 Tip (-)

10 Medtronic warranty

For complete warranty information, see the accompanying
warranty document.

11 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.

14

Consult instructions for use

Date of manufacture

Manufacturer

Authorized representative in the European com­munity

For US audiences only

Use by

Reorder number

Serial number

Lot number

Table 5. Explanation of symbols on package labeling (continued)

Symbol Explanation

Package contents

Product documentation

Accessories

Inner diameter

Lead

Lead length

Transvenous ventricular lead

Transvenous lead with two defibrillation
electrodes

Pace

Sense

Defibrillation

Extendable and retractable screw-in

Steroid eluting

Lead introducer

Lead introducer with guide wire

15

World Headquarters

*M953938A001*

Medtronic, Inc.
710 Medtronic Parkway
Minneapolis, MN 55432
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]

Europe/Africa/Middle East Headquarters

Medtronic International Trading Sàrl
Route du Molliau 31
Case Postale 84
CH-1131 Tolochenaz
Switzerland
www.medtronic.com
Tel. [phone]
Fax [phone]

Medtronic E.C. Authorized Representative

Medtronic B.V.
Earl Bakkenstraat 10
6422 PJ Heerlen
The Netherlands
Tel. [phone]
Fax [phone]

Technical manuals:
www.medtronic.com/manuals

© Medtronic, Inc. 2012
M953938A001A
2012-10-05