ST JUDE MEDICAL 1944 IsoFlex J Shape Pacing Lead User Manual

IsoFlex™ Pacing leads
Model 1944 Model 1948
User’s Manual

CAUTION: Federal (USA) law restricts this device to sale by or on the order of a physician.
WARNING: This product can expose you to chemicals including ethylene oxide, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
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Pat. http://www.abbott.com/patents
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Description

IsoFlex™ leads are bipolar, steroid-eluting, passive-fixation implantable pacing leads with Optim™ insulation. IsoFlex Model 1948 leads are designed for long-term pacing and sensing in either the right atrium or the right ventricle. IsoFlex Model 1944 leads are designed for long-term pacing and sensing in the right atrium. IsoFlex Models 1944 and 1948 leads are insulated with Optim, a silicone polyurethane copolymer. The table below lists the available models and their features.
Table 1. IsoFlex models and features

Model| Features|
---|---|---
1948| Straight| Optim insulation
1944| J-shaped| Optim insulation

Additional features of all IsoFlex leads are:

• Steroid Elution – Less than one milligram (mg) of dexamethasone sodium phosphate (DSP) is slowly released through the tip electrode upon contact with body fluid. The drug is intended to promote a low chronic stimulation threshold by suppressing the local inflammatory response to a foreign body.
• Fast Pass™ coating – The Optim outer insulation is coated to create a highly lubricious surface.

NOTE: IsoFlex low-polarization bipolar leads are compatible with the AutoCapture™ pacing system contained in St. Jude Medical pulse generators.
For additional details on these leads, see Technical Specifications (page 13).

Indications/Intended Use

IsoFlex™ Model 1948 leads are 7 F, steroid eluting, passive fixation (tined) straight body leads designed for use with compatible pulse generators to provide permanent pacing and sensing in either the right atrium or right ventricle.
IsoFlex Model 1944 leads are 7 F, steroid eluting, passive fixation (tined) J-shaped leads designed for use with compatible pulse generators to provide permanent pacing and sensing in the right atrium. Table 2. Accessories and their intended uses

a
device.
Retainer| Retain lead tip prior to implantation.
Vein lifter| Lift and dilate the vein at the lead entry site.
Suture sleeve| Protect the lead from damage when it is secured to the venous entry site

NOTE: These and other accessories may be ordered separately. For more information, contact your local St.
Jude Medical representative.

Contraindications

The use of IsoFlex™ leads is contraindicated:

• in patients who are expected to be hypersensitive to a single dose of 1.0 milligram of dexamethasone sodium phosphate.
• The use of the Model 1948 is also contraindicated:
•  in the presence of tricuspid atresia and in patients with mechanical tricuspid valves.

Package Contents

The contents of the package are sterile. Each package contains:

• One passive-fixation pacing lead with a suture sleeve attached
•  One vein lifter
• One style guide (the funnel)
• One stylet holder (stylet ring)
• One tip retainer (to be removed prior to implant)
• Stainless steel styles with knob colors designating the degree of firmness. See Stylet Color Codes (page 14).

Packaging

Check the “use-before” date on the package label. Do not implant a lead if its “use-before” date has expired.
Figure 1. The outer tray cover may be peeled back by a person not prepared for the sterile field.
1. Unsterile field

Opening the Inner Tray
In order to preserve sterility, operating room procedures should be followed when opening the inner tray.
CAUTION: Avoid bringing the lead into contact with any sharp object which could puncture or otherwise damage the insulation. Avoid handling the lead with surgical tools.
Figure 2. Only a person prepared for the sterile field may open the inner tray.
2. Sterile field

Storage

• Store the lead at temperatures between -5°C (23°F) and 50°C (122°F).
• The lead package has been sterilized with ethylene oxide for direct introduction of the inner tray into the surgical field.
• Do not implant the lead if the sterility indicator dot within the inner package is purple, because it may not have been sterilized.
• Before the package is opened, inspect it visually for any damage that may have compromised sterility.

Sterilization

• If the sterile package has been compromised, contact St. Jude Medical.
• The package contents have been sterilized with ethylene oxide before shipment. This lead is for single use only and is not intended to be resterilized.

Warnings and Precautions

• Implanted cardiac leads are subjected to a hostile environment within the body due to constant, complex flexural and torsional forces, interactions with leads and/or the pulse generator, or other forces associated with cardiac contractions and patient physical activity, posture, and anatomical influences. Cardiac leads’ functional lifetimes can be affected by these and other factors.
• Patients with implanted leads should avoid diathermy, even if the device is programmed off, as it may damage tissue around the implanted electrodes or may permanently damage the pulse generator.

Lead Selection

• Before opening the lead package, confirm that the lead is compatible with the pulse generator to be implanted.

Storage and Handling

• Do not stretch, crush, kink, or bend the lead. Leads may be damaged by improper handling before and during implant or by excessive mechanical stress post-implantation.
• Do not bring the lead into contact with sharp objects which could puncture or otherwise compromise the insulation.
• Handle the lead only with powderless, sterile surgical gloves.
• Avoid handling the lead with surgical tools such as hemostats, clamps, or forceps.
• Carefully remove the tip retainer from the lead before implantation.
• Carefully check that the suture sleeve moves freely before implantation.
• Leads have an electrostatic attraction for particulate matter; do not expose them to lint, dust or other such materials.
• Do not touch or handle the lead tip electrode.
• Do not immerse the lead body in mineral oil, silicone oil, or any liquid other than sterile saline or injectable fluid.
• Do not immerse the tip electrode in any fluid prior to implantation; immersion of the electrode may cause a small amount of steroid to be prematurely eluted.

Lead Evaluation and Testing

• Use only battery-powered equipment during lead implantation and testing to protect against fibrillation
• Exercise extreme caution when testing leads. which may be induced by alternating current.
• Use only properly grounded line-powered equipment in the vicinity of the patient during the implant procedure.
• Insulate lead connector pins from any leakage currents that may arise from line-powered equipment.

Lead Implantation

• Lead implantation should be performed only when proper emergency facilities for cardioversion and/or defibrillation are available.
• The manipulation of any and all hardware while in the vascular system should only be performed under continuous fluoroscopic monitoring.
• During this procedure, it is advisable to also have echocardiographic equipment available.
• Failure to use the suture sleeve to secure the lead may result in lead dislodgment or in damage to the possible during entry of the lead into the vein.
• If subclavian venipuncture is used for lead introduction, it is important to insert the lead as lateral as lead’s insulation and/or conductor coil.

Adverse Events
Adverse Events in the IsoFlex S Model 1642T and1646T Leads

The design of the IsoFlex™ leads is based on that of the IsoFlex S Models 1642T and 1646T leads. The IsoFlex S clinical trial involved 65 Model 1642T and 93 Model 1646T leads implanted in 95 patients.
Cumulative implant duration by lead location is as follows:

• Atrium: 7704 days (mean implant duration 120.4 days, range 1 to 210 days)
•  Ventricle: 12144 days (mean implant duration 129.2 days, range 35 to 219 days)

No deaths were reported.
Table 3. Adverse event complications reported in the IsoFlex S model 1642T and the 1646 T leads

Type of complication| Number of patients (% of total)| Number of Events| Events per Patient Month1| Events per Device Year2
---|---|---|---|---
Lead dislodgment‑Acute
(Atrial)| 3 (3.2)| 3| 0.00743| 0.05514

1 This rate is obtained by dividing the number of adverse events by the total patient cumulative implant duration in months (403.8 patient months).
2 This rate is obtained by dividing the number of adverse events by the total lead cumulative implant duration in years. Total lead implant duration was calculated by adding the atrial and ventricular lead implant durations.
Table 4. Adverse event observations reported in the IsoFlex S model 1642T and the 1646 T leads

Type of observation| Number of patients (% of total)| Number of Events| Events per Patient Month1| Events per Device Year2
---|---|---|---|---
Arrhythmia‑Persist ent Atrial Fibrillation| 1 (1.1)| 1| 0.00248| 0.01838
Hematoma| 1 (1.1)| 1| 0.00248| 0.01838
Medication reaction| 1 (1.1)| 1| 0.00248| 0.01838

1 This rate is obtained by dividing the number of adverse events by the total patient cumulative implant duration in months (403.8 patient months).
2 This rate is obtained by dividing the number of adverse events by the total lead cumulative implant duration in years. Total lead implant duration was calculated by adding the atrial and ventricular lead implant durations.

Observed Adverse Events

An adverse event was defined as any unfavorable clinical event, which impacted or had the potential to impact the health and safety of a Clinical Study participant caused by, or associated with a study device or intervention. An adverse event can occur during exposure to the procedure, exposure to the device and/or at implant. All adverse events were classified as a complication or an observation. A complication was defined as any adverse event resulting in an injury or invasive procedure which would not have occurred in the absence of the implanted device and/or system components. An observation was defined as any adverse event that was not associated with injury to the patient or invasive intervention.
The table above (Adverse event complications) summarizes the adverse events reported and classified as complications. The second table above (Adverse event observations) summarizes the adverse events reported and classified as observations.

Potential Adverse Events

Potential complications associated with the use of the IsoFlex™ family of leads are the same as with the use of any lead and include:

• Cardiac perforation
• Cardiac tamponade
• Damage to vessels
• Embolism
• Excessive bleeding
• Induced atrial or ventricular arrhythmias
• Infection
• Loss of pacing and or sensing due to dislodgment or mechanical malfunction of the lead
• Phrenic nerve stimulation
• Tissue necrosis
• Thrombosis
•  Valve damage

Phrenic nerve or direct diaphragmatic stimulation may also be a result of the lead position. Complications reported with direct subclavian venipuncture include pneumothorax, hemothorax, laceration of the subclavian artery, arteriovenous fistula, neural damage, thoracic duct injury, and cannulation of other vessels, massive hemorrhage, and, rarely, death.

Clinical Trials

A multi-center, prospective clinical trial was conducted to compare capture and sensing thresholds of the IsoFlex S Model 1642T atrial lead and the Model 1646T ventricular lead at 1 month. The capture and sensing threshold data of the legally marketed endocardial, steroid-eluting, passive-fixation Passive Plus DX leads Model 1342T and Model 1346T were used as a historical control.
Lead electrical performance characteristics, including capture thresholds, sensing thresholds, and lead impedances, were evaluated at implant, prior to discharge, and at 1-month (± 7 days) and 3 months (±14 days) post-implant. A total of 158 leads were implanted in 95 patients. Of the 158 leads implanted, 65 were Model 1642T and 93 were Model 1646T. The reported gender for the patient population was 46.2% females and 53.9% males. The reported age of the patient population at the time of implant ranged from 55 to 91 years, with a mean of 77.6 ± 8.7 years.
Analysis of the clinical data demonstrated that the atrial and ventricular capture and sensing thresholds for the IsoFlex S lead Models 1642T and 1646T were clinically and statistically similar to the capture and sensing thresholds of the Passive Plus DX lead Models 1342T and 1346T used as a historical control. The IsoFlex S lead Models 1642T and 1646T bipolar capture and sensing threshold analysis at 1-month is summarized in Table 4. Atrial and ventricular capture and sensing threshold data for the IsoFlex S leads are summarized in Table 5 and Table 6. The bipolar lead impedance values for the IsoFlex S lead Models 1642T and 1646T are summarized in Table 7 and were statistically significantly higher than for the Passive Plus DX lead Models 1342T and 1346T used as a historical control.
The AutoCapture pacing system has been shown to be effective with a 100% and 99% recommendation for the use of AutoCapture by the E/R Sensitivity Test at implant and 1 month, respectively.
Table 5. IsoFlex S bipolar capture thresholds at one month

Atrial Sensing Threshold
(mV)| 3.1 ± 1.4 (53)| (2.7, 3.4)| <0.001

Table 5. IsoFlex S bipolar capture thresholds at one month

1T-test for equivalence to historical control using data from Final Report, Passive Plus DX Model 1342T/ 1346T, CD 0067 Rev. A, Dec 1999.
2 Measured at 0.5 ms pulse width.
Table 6. IsoFlex S capture thresholds (V) at 0.5 ms Pulse Width

Atrial Leads
Mean ± SD (N)| Ventricular Leads
Mean ± SD (N)
---|---
Follow-Up| Unipolar| Bipolar| Unipolar| Bipolar
Implant| 0.6 ± 0.3 (55)| 0.6 ± 0.2 (56)| 0.4 ± 0.2 (93)| 0.5 ± 0.2 (93)
Pre-Discharge| 0.5 ± 0.2 (51)| 0.7 ± 0.3 (51)| 0.4 ± 0.2 (87)| 0.5 ± 0.2 (88)
1-Month| 0.7 ± 0.9 (49)| 0.8 ± 0.8 (52)| 0.6 ± 0.3 (82)| 0.7 ± 0.5 (82)
3-Month| 0.7 ± 0.6 (43)| 0.8 ± 0.7 (43)| 0.6 ± 0.5 (65)| 0.8 ± 0.5 (66)

Table 7. IsoFlex S sensing thresholds (mV)

Atrial Leads
Mean ± SD (N)| Ventricular Leads
Mean ± SD (N)
---|---
Follow-Up| Unipolar| Bipolar| Unipolar| Bipolar
Implant| 2.6 ± 1.4 (61)| 3.0 ± 1.4 (61)| 9.9 ± 2.8 (85)| 10.3 ± 2.8 (85)
Pre-Discharge| 2.6 ± 1.5 (55)| 3.0 ± 1.4 (56)| 9.9 ± 3.0 (81)| 10.1 ± 2.9 (81)
1-Month| 2.5 ± 1.3 (52)| 3.1 ± 1.4 (53)| 10.4 ± 2.7 (77)| 10.5 ± 2.8 (79)
3-Month| 2.6 ± 1.3 (43)| 3.1 ± 1.3 (43)| 10.2 ± 2.8 (66)| 10.8 ± 2.5 (65)

Table 8. IsoFlex S bipolar lead impedance (W)

1Two sample t-tests utilizing data from Final Report, Passive Plus DX Model 1342T/1346T, CD 0067 Rev A., Dec 1999.

Conformance to Standards
The lead complies with IS‑1 connector standard ISO 5841‑3.
Clinician Use Information
Physician Training
Physicians should be familiar with sterile implant procedures and follow-up evaluations. The following sections describe various stages of lead implantation. Procedures included in these sections are only recommendations. Actual implant procedures are left to the discretion of the implanting physician.

Directions for Use

Lead Preparation
It is important that the implanting physician completely understand the mechanical operation of this lead before surgery.
Lead/pulse generator compatibility should be confirmed with the pulse generator and/or lead manufacturer(s) prior to the implantation of a pacing system.

Lead Introduction
CAUTION:

• If using a percutaneous lead introducer with a hemostasis valve, make sure the valve allows for the appropriate passage of the lead without damaging the lead body. lead function.
• Be certain the vein lifter does not puncture the insulation of the lead. This could prevent proper
• Do not use excessive force while inserting the stylet.
• When subclavian venipuncture is used for lead introduction, it is important to insert the lead as lateral as possible during entry of the lead into the vein.
• Do not grip the lead with surgical instruments.
• Avoid positioning the lead so that it becomes sharply bent or subjected to tension.
• Do not leave a lead unconnected in a patient unless the lead is capped.

Selecting and Accessing a Vein
The suggested entry site is the left cephalic vein entered via a venous cutdown. Alternatively, the lead may be implanted percutaneously via the left subclavian vein. However, studies 1 indicate that the incidence of lead damage may be decreased with the lead placed by cephalic vein cutdown or, if a percutaneous subclavian entry is chosen, with a puncture site as lateral as possible (in the area under the lateral two-thirds of the clavicle, lateral to the subclavius muscle). The right subclavian vein and the internal jugular vein may also be used.

CAUTION: The manipulation of intravascular hardware should be performed only under continuous fluoroscopic monitoring.

Cut-down technique
Any of the veins named other than the subclavian vein may be used for the cut- down technique.

1. Isolate the desired vein and make a small incision for lead insertion, under direct vision.
2. Use the vein lifter to lift and dilate the vein. Insert the vein lifter’s tapered end into the vein and gently lift (see figure below).

Figure 3. Vein lifter

Subclavian puncture method
The subclavian puncture method requires the use of a percutaneous lead introducer.

1Magney, J.E., Flynn, D.M. Parsons, J.A., et al.: Anatomical Mechanisms Explaining Damage to Pacemaker Leads, Defibrillator Leads, and Failure of Central Venous Catheters  Adjacent to the Sternoclavicular Joint. PACE 16 (I):445-457, 1993.

1. Distend the subclavian vein by raising the patient’s legs to a 45° angle or by using the Trendelenburg position. The vein will be easier to locate if the patient is well hydrated.
   (see below).

2.  Identify and distend the subclavian vein and use the needle in the introducer kit to puncture the vein
   NOTE: When subclavian venipuncture is used for lead introduction, it is important to insert the lead as lateral as possible during entry of the lead into the vein.
   Figure 4. Using the needle in the introducer kit to puncture the subclavian vein.

3. Once venous access is achieved, insert the introducer’s guidewire through the needle and withdraw the needle.

4. Advance the dilator and sheath over the guidewire and into the vein.

5. To remove the dilator, hold the T-handle of the sheath and rotate the dilator and its locking clip counterclockwise °.

6. Retract the guidewire and dilator, leaving the sheath in position. Manually compress or cover the opening of the introducer sheath to avoid inadvertent air aspiration.

7. Introduce the pacing lead with inserted stylet into the sheath and advance it into position. See Lead Placement (page 9).

8. When the lead is properly positioned, remove the sheath by peeling the sheath symmetrically down and away.

9. For more information on the subclavian puncture method using the introducer kit, please consult the introducer manual.

Introducing Two Leads
Dual-chamber pacemakers require the implantation of two leads — one in the atrium and the other in the ventricle. Two leads may be implanted in one of three ways:

1. Making two venipunctures
2. Making one puncture and using an introducer sufficiently large to accommodate both leads

2 These instructions assume the use of a St. Jude Medical introducer. If another type of introducer is used, follow the manufacturer’s instructions.
To introduce the second lead, reinsert the guidewire (and straightener as tip deflector, if desired) using the first sheath. Remove the first sheath and place the second sheath over the guidewire. The guidewire and dilator can then be removed as a unit and the second lead can then be inserted through the second sheath. Using the retained guidewire technique. For this technique, use the introducer in one venipuncture and remove the guidewire and dilator together before the lead is inserted into the sheath.

Stylets

Each IsoFlex™ lead comes supplied with several styles. The stylet is inserted into the lead to provide sufficient rigidity so the lead can be manipulated through the vein and into the heart.
Do not use excessive force when inserting the style into the lead before lead introduction.
Once the lead is believed to be in an appropriate position, remove the stylet before testing the lead for mechanical stability or making intraoperative measurements.
The color of the style knob indicates the degree of firmness of the style. Stylet length is also indicated on the knob.
NOTE: During the lead introduction, avoid contaminating the style with blood. Blood introduced into the core of the lead via the stylet may cause the stylet to bind and prevent it from being advanced or manipulated. If this occurs, remove the lead and replace it with a new lead.

Lead Placement

Ventricular Lead Placement

1. Under fluoroscopic observation, advance the lead cautiously into the right atrium. If resistance is encountered, pull the lead back a short distance and readvance it,  repeating this procedure as often as necessary. Once past the obstruction, cautiously readvance the stylet.
2. Remove the straight style.
3. Take a new stylet, curve it gently, and insert it into the lead. The curve helps the lead negotiate its way across the tricuspid valve as it is manipulated into the right ventricle.  Once the lead is in the right ventricle, retract the stylet slightly to minimize the chance of cardiac wall perforation.

An alternate lead placement method involves using the straight stylet:

1. With the lead in the right atrium, retract the stylet a few centimeters so the lead tip is floppy.

2. Gently advance sufficient lead within the right atrium so that a loose loop forms.

3. Under fluoroscopic observation, allow this loop to flip or prolapse through the tricuspid valve so that the loop passes through the valve first, drawing the tip through afterward.
   Figure 5. Ventricular Lead Placement

4. Once the lead is in the right ventricle, advance it cautiously toward the right ventricular apex. To avoid the inadvertent placement of the lead in the coronary sinus, it may be useful to advance the lead through the right ventricle and into the pulmonary artery, followed by gently withdrawing the lead until the tip lodges into the apex.

5. Under fluoroscopic observation, verify that the lead has entered the pulmonary artery.

6. Replace the curved stylet with a straight stylet if necessary, then gently pull the lead back into the right ventricle.

Proper positioning requires that the lead’s tines wedge under the trabeculae and resist removal under gentle traction. The lead tip should point anteriorly toward the apex with the tip showing a slight curve. Lateral fluoroscopy may be necessary to verify that the lead is not pointing posteriorly, which can indicate that the lead is in the coronary sinus.  On AP fluoroscopy, the lead should be wholly in the cardiac shadow. If not, the lead may be in the coronary sinus, a coronary vein, or may have perforated the cardiac wall. If the lead is unintentionally in the coronary sinus or a coronary vein or is believed to have perforated, retract it gently and reposition it.
When the lead is in position, fully withdraw the stylet prior to assessing capture and sensing thresholds.

Atrial Lead Placement

1. Under fluoroscopic observation, advance the lead cautiously toward the heart. If resistance is encountered, pull the lead back a short distance and readvance it, repeating this procedure as often as necessary. Once past the obstruction, cautiously readvance the stylet.
2. Advance the lead into the right atrium just below the superior vena cava. Use fluoroscopy to verify Figure 6. Atrial lead placement
3. When the lead reaches the junction of the right atrium and superior vena cava, hold the stylet stationary and advance the lead over the stylet into the right atrium under fluoroscopic observation. The lead should point in an anteromedial direction. Gently retract the stylet several centimeters further so that the lead’s distal end resumes its J- shape (Figure 6). This should allow the lead tip to lodge in the atrial appendage.
4. Verify the lead’s position. When the lead is properly placed, its J- curve should straighten a little when the lead is slightly retracted. Under AP fluoroscopy, the lead tip should point medially toward the left. It should sway slightly from side to side with each atrial contraction (when there is AV synchrony).
5. Verify the lead’s shape. A loose J-shape of the lead is preferred, as shown in the figure above. If the lead is properly positioned, a very slight rotation of the lead will be seen to change the position of the body of the J, but not the tip.
6. Verify the lead’s tension. Some physicians assess proper lead tension by having the patient breathe deeply several times. On maximal expiration, the J will appear almost closed; on maximal inspiration, the J will open to almost an L shape.
7. When the lead is in the proper position, fully withdraw the stylet.

Intraoperative Measurements

Verify the lead’s stimulation threshold and sensing capability during implantation. A measuring device such as a pacing system analyzer (PSA) is recommended for these electrical measurements.

WARNING: A pacing lead inserted into the heart presents a direct, low- impedance pathway for current flow to the myocardium. Use only battery-powered test equipment for electrical measurements.
Connection to the Pacing System Analyzer

1. Remove the percutaneous lead introducer and stylet from the lead once the lead is in position.
2. Use the PSA cables to connect the terminal pin of the implanted pacing lead to the analyzer. Program the PSA off or to a passive setting while making the connections.
3. For a bipolar lead with an in-line connector, connect the negative PSA cable (cathode) to the lead connector’s terminal pin and the positive PSA cable (anode) to the lead connector’s terminal ring (associated with the anode ring electrode). Carefully apply alligator clips to the in-line bipolar terminal pin to avoid damaging the insulation between terminal pins.

For more information on the use of the PSA, please refer to the PSA manual.
Stimulation and Sensing Threshold Values

Verify the stimulation threshold and sensing threshold at the implant.
Using a 0.4 ms pulse width and assuming a 500-Q load, it should be possible to obtain the acute stimulation thresholds listed in the table below. If the stimulation threshold values are greater than the recommended values, reposition the lead.
Recommended acute sensing thresholds are also shown in the table below. If the sensing threshold is lower than the recommended values, reposition the lead.
Table 9. Recommended acute stimulation and sensing thresholds (0.4 ms pulse width, 500 Q load)

| Atrial| Ventricular
---|---|---
Acute Stimulation Threshold| <1.5 V
<3.0 mA| <1.0 V
<2.0 mA
Acute Sensing Threshold| >2.0 mV| >5.0 mV

Mechanical Stability
Verify the mechanical stability of the lead by setting an external pacemaker or PSA to a pulse amplitude 0.1– 0.5 V above the stimulation threshold and a rate that is 10–20 bpm faster than the patient’s intrinsic rhythm. Have the patient breathe deeply or cough. Verify with both fluoroscopy and the ECG that the lead remains stable and capture is maintained.

Phrenic Nerve Stimulation
Evaluate the patient for phrenic or diaphragmatic stimulation. Use the external pacemaker or PSA to program a pulse amplitude equal to the maximum output of the pulse generator while checking that no phrenic or diaphragmatic stimulation occurs and verifying with fluoroscopy and the ECG that the lead remains stable.

Anchoring the Lead
A suture sleeve is used to secure the lead to the vein or underlying fascia and to prevent damage to the insulation of the conductor which otherwise might be caused by the ligature. When the positioning and measurements are complete, firmly secure the lead with the suture sleeve to prevent the lead from sliding along the vein and rotating. The ligature around the sleeve should be tight enough to hold the lead still, but not so tight as to damage the insulation or the conductor. Sew the suture sleeve to the tissue. Tie sutures firmly around each available groove on the suture sleeve. The most distal groove may be used to tie off the vein over the suture sleeve.

Figure 7. Suturing the lead![ST JUDE MEDICAL 1944 IsoFlex J Shape Pacing Lead

• Anchoring](https://manuals.plus/wp-content/uploads/2022/08/ST-JUDE- MEDICAL-1944-IsoFlex-J-Shape-Pacing-Lead-Anchoring.png)

  1. Vein
  2. Fascia
  3. Lead body
  4. Suture sleeve

CAUTION:

• Do not slide the suture sleeve over the electrode ring.
• Suture sleeve sticking can occur. If this occurs, carefully twist the sleeve of the ring toward the connector pin; pulling the suture sleeve when it is positioned over the electrode ring may cause a tear in the lead body near the electrode ring.
• Do not apply the ligature directly to the lead body, as this can damage the lead’s insulation or conductor coil.
• Do not tie the suture around the suture sleeve and lead too tightly, as this may result in excessive stress applied to the lead body.
• Use the suture sleeve to distribute the tension created by the suture. Failure to use the suture sleeve may result in damage to the lead’s insulation or conductor coil.
• If an accessory suture sleeve is used, it should be used as a replacement for the existing suture sleeve on the lead and should not be used in conjunction with the existing suture sleeve. The use of multiple suture sleeves to secure the lead is not recommended as it may result in damage to the lead.

If an accessory suture sleeve is used:

1. Carefully open the slit in the sleeve and position the sleeve on the lead body.
2. Follow the procedure above to suture and secure the sleeve.

Chronic Repositioning
Chronically implanted endocardial pacing leads should not be repositioned except in special circumstances.
Connection to the Pulse Generator
Grasp the lead connector as close as possible to the connector pin while inserting the lead connector straight into the pulse generator port. If necessary, regrip the lead and continue to insert the lead connector until it is fully seated in the pulse generator port.

CAUTION:
Orient the excess lead length and the pulse generator to minimize the potential for insulation damage resulting from lead-to-lead or pulse generator-to-lead interaction. For example, minimize the potential for leads lying on top of each other under the pulse generator and ensure that there are no sharp bends in the lead. Lead insulation damage can create an alternate electrical current path which may result in compromised therapy delivery. Current practice indicates that a subcutaneous pocket is preferred over a subpectoral pocket.

Do not allow the lead to becoming twisted. Instead, after connecting the lead, roll up surplus lead by rotating the pulse generator. Place the loops that this makes under the pulse generator.
Lead Extraction
Infection of the implantable device system, particularly sepsis, may require the removal of both the pulse generator and the lead(s).
CAUTION: Lead extraction carries with it clinical risk. If a pacing lead must be removed, great care should be exercised.
WARNING: An explanted pacing lead should never be implanted in another patient.
If it is necessary to abandon an indwelling lead, remove its connector pin from the pulse generator and cap the lead using the standard cap of the lead manufacturer. Cutting an indwelling lead is not recommended; this may cause the insulation to separate from the conductor coil and leave an exposed wire in the body.
If the lead or any portion of it is extracted, return it to St Jude Medical.

Technical Support

St. Jude Medical maintains 24-hour phone lines for technical questions and support:

• 1818 362 6822
• 1800 722 3774 (toll-free within North America)
• +46 8 474 4147 (Sweden)
• +612 9936 1200 (Australia)
• manuals.sjm.com

For additional assistance, call your local St. Jude Medical representative.

Technical Specifications

Table 10. Technical Specifications

| 1944 (J-shaped)| 1948 (straight)
---|---|---
Length (cm)| 46, 52| 46, 52, 58
Lead introducer (minimum recommended)| 7 french|
Electrode  configuration Tip electrode Ring electrode| semispherical shape, steroid coating
cylindrical|
Electrode spacing Tip to ring
electrode (mm)| 10| 12
Connector size Sense/pace| IS-1 bipolar (3.2 mm)|
Lead body insulation| Optim™5 with exterior Fast-Pass™ coating|

3Furman S, Hayes DL, Holmes DR: A Practice of Cardiac Pacing. 3rd ed. New York: Futura Publishing, Inc.; 1993:286-289.Belott, PH, Reynolds, DW. Permanent Pacemaker  and Implantable Cardioverter-Defibrillator
Implantation. In: Ellenbogen KA, Kay GN, Wilkoff BL, eds. Clinical Cardiac Pacing and Defibrillation. 2nd ed.
Philadelphia, PA: WB Saunders; 1955:613-615. 4
St. Jude Medical IS‑1 lead connectors are compatible with connector cavities that conform to the international connector standard ISO 5841‑3.
5 Optim is a silicone-polyurethane copolymer.

Table 10. Technical Specifications

Electrode surface area

Electrical resistance (W)

Tip to connector pin| 46 cm: 43.2-64.8
52 cm: 48-72| 46 cm: 43.2-64.8
52 cm: 48-72
58 cm: 52.8-79.2
---|---|---
Ring to connector ring| 46 cm: 8-12
52 cm: 9.6-14.4c| 46 cm: 59.2-88.8
52 cm: 65.6-98.4
58 cm: 72-108
Maximum
diameter (mm)| 2.1| 2.1
---|---|---

Stylet Color Codes

Table 11. Stylet color codes

MP35N LT is a trademark of SPS Technologies.

St. Jude Medical
Cardiac Rhythm
Management Division
15900 Valley View Court
Sylmar, CA 91342 USA
+1 818 362 6822
sjm.com 2021-12
ARTEN600228717 A

Documents / Resources

| ST JUDE MEDICAL 1944 IsoFlex J Shape Pacing Lead [pdf] User Manual
1944, 1948, IsoFlex J Shape Pacing Lead, J Shape Pacing Lead, Pacing Lead, 1944, Lead
---|---

References

• Instructions for Use Website
• Abbott | Life-Changing Cardiac and Vascular Technology
• Patents | Abbott Products | Abbott U.S.
• P65Warnings.ca.gov

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