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

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:

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

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2 purple fixation tools

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1 purple stylet guide

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1 slit anchoring sleeve

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1 vein lifter

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extra stylets

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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.

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.

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).

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

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

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.

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

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

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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.

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

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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.

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

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

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

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

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

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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.

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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.

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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.

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

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

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Avoid overbending or kinking the stylet.

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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.

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

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

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

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

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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

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.

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:

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acceleration of tachyarrhythmias (caused by device)

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air embolism

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bleeding

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body rejection phenomena, including local tissue reaction

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cardiac dissection

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cardiac perforation

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cardiac tamponade

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chronic nerve damage

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constrictive pericarditis

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death

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device migration

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endocarditis

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erosion

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excessive fibrotic tissue growth

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extrusion

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fibrillation or other arrhythmias

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fluid accumulation

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formation of hematomas/seromas or cysts

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heart block

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heart wall or vein wall rupture

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hemothorax

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infection

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keloid formation

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lead abrasion and discontinuity

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lead migration/dislodgement

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mortality due to inability to deliver therapy

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muscle and/or nerve stimulation

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myocardial damage

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myocardial irritability

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myopotential sensing

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pericardial effusion

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pericardial rub

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pneumothorax

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

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threshold elevation

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thrombosis

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thrombotic embolism

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tissue necrosis

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valve damage (particularly in fragile hearts)

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venous occlusion

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venous perforation

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

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insulation failure

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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

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

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