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Temporary cardiac pacing 

Temporary cardiac pacing
Chapter:
Temporary cardiac pacing
Author(s):

Jonathan Timperley

DOI:
10.1093/med/9780199687831.003.0007
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date: 18 September 2019

General principles

Recommendations for temporary pacing are based on consensus of clinical opinion rather than trial data. If a patient requires a permanent pacemaker, where possible a temporary wire should be avoided and a permanent system implanted. Patients requiring a permanent system should only undergo temporary pacing for syncope at rest, haemodynamic compromise, or bradycardia-induced ventricular tachyarrhythmias. Sinus node disease rarely requires temporary pacing.

The indications can be split into two broad categories: emergency (commonly with acute myocardial infarction (MI)) and semi-elective. In acute anterior MI, complete heart block is associated with a poor prognosis, associated with a broad QRS and represents tissue necrosis in the His-Purkinje system. Complete heart block in acute inferior MI is usually reversible, associated with a narrow QRS, and may respond to atropine.

Risk of third-degree atrioventricular block after infarction

The MILIS (Multicentre Investigation of the Limitation of Infarct Size) study has recommended a method of risk stratification for the development of third-degree AV block following MI.[1] One point is scored for each of the following:

  • First-degree AV block.

  • Type I second-degree AV block.

  • Type II second-degree AV block.

  • Left anterior fascicular block (LAFB).

  • Left posterior fascicular block (LPFB).

  • Right bundle branch block (RBBB).

  • Left bundle branch block (LBBB).

The risk of third-degree AV block is predicted by the score as follows.

Score

Risk of third-degree AV block (%)

0

1.2

1

7.8

2

25

3

36.4

ACC/AHA guidelines

Emergency

Acute MI (class I—good evidence for benefit)

  • Asystole.

  • Symptomatic bradycardia (sinus bradycardia with hypotension and type I second-degree AV block not responsive to atropine).

  • Bilateral bundle branch block (alternating BBB or RBBB with alternating LAHB/LPHB (left anterior hemiblock/left posterior hemiblock).

  • New or indeterminate age bifascicular block with first-degree AV block.

  • Mobitz type II second-degree AV block.

Bradycardia not associated with acute MI

  • Asystole.

  • Second or third-degree AV block with haemodynamic compromise.

  • Ventricular tachyarrhythmias secondary to bradycardia.

Acute MI (class IIa/b—some evidence for benefit)

  • RBBB with LAFB or LPFB (new or indeterminate).

  • RBBB with first-degree AV block.

  • LBBB (new or indeterminate).

  • Recurrent sinus pauses (> 3 s); not responsive to atropine.

  • Incessant VT for overdrive pacing.

  • Bifascicular block of indeterminate age.

  • RBBB.

Semi-elective

  • Support for procedures that may promote bradycardia.

  • General anaesthesia with:

    • Second or third-degree AV block.

    • Intermittent AV block.

    • First-degree AV block and bifascicular block.

    • First-degree AV block and LBBB.

  • Cardiac surgery:

    • Aortic surgery.

    • Tricuspid surgery.

    • Ventricular septal defect (VSD) closure.

    • Ostium primum atrial septal defect (ASD) repair.

  • Rarely considered for percutaneous coronary intervention (PCI) (usually right coronary artery).[2]

Preparation for transvenous temporary pacing

As with all techniques, preparation is important before starting a procedure. Ensure the following are available or set up before starting.

Equipment

  • Peripheral IV access.

  • Three-lead ECG monitoring (avoid leads on the chest that may obscure screening).

  • Transcutaneous external pacing.

  • Sterile drapes, gown, and gloves.

  • Iodine skin preparation or equivalent.

  • Lidocaine for local anaesthesia.

  • Introducer sheath with haemostatic valve (usually 6 F and at least one size larger than the electrode).

  • Temporary pacing electrode (semi-rigid or flotation).

  • Temporary pulse generator.

  • Connecting leads for pacing box to the electrode.

  • Suture material and scalpel for sheath and the electrode.

  • Transparent occlusive dressing.

  • X-ray equipment and operator.

Patient preparation

  • Patients need to be on a dedicated pacing bed in order to accept the C-arm of the X-ray equipment. It is possible to insert a balloon flotation pacing wire without X-ray guidance but this is technically challenging and may achieve less satisfactory results.

  • Sedation is usually not required.

  • The patient should be inclined slightly head down.

  • Select venous access site (subclavian, internal jugular, or femoral) and side of access (left or right).

  • Reposition any transcutaneous pacing leads or electrocardiogram (ECG) monitoring electrodes that are too close to the access site.

  • Once you have scrubbed up, prepare the skin in the venous access area, usually with an iodine-based surgical wash. If subclavian or internal jugular access is to be used prepare both sites so that either can be used without the need to re-prepare the patient if one fails.

  • Position appropriate sterile drapes around the venous access site and fix with clips, if available.

  • Infiltrate the access site with local anaesthetic, for example lidocaine 1%.

Choice of venous access

The choice of access is often dependent on individual experience, but consideration should also be given to the length of time for which it is anticipated that the temporary wire will be needed.

  • Current British Cardiovascular Society (BCS) guidelines recommend the right internal jugular vein route as this is felt to be more stable over longer periods and can be kept sterile.

  • Subclavian access is a familiar approach for those who regularly perform permanent pacing but there is a higher risk of pneumothorax.

  • In an emergency situation, where immediate pacing is required (e.g. no transcutaneous pacing available), the femoral route is often easiest for both access and lead positioning. Bleeding can also be easily controlled with pressure and therefore is useful in the anticoagulated or thrombolysed patient. However, over the longer term femoral pacing wires restrict patient mobility, are more liable to displace, and less easy to keep clean.

  • If available, ultrasound guidance is recommended to gain central venous access.

Internal jugular vein cannulation

The right internal jugular approach (Figure 7.1) offers the most direct route to the right ventricle and has the lowest complication and highest success rate. Compared to subclavian approach it has a reduced risk of pneumothorax and allows for direct compression for haemostasis if bleeding occurs. The left internal jugular should be avoided due to the angulation required and the presence of the thoracic duct.

  • Prepare and drape the skin; position patient in slight head-down position (Temporary cardiac pacing p. [link]).

  • Identify the apex of the triangle between the clavicular and manubrial heads of sternocleidomastoid.

  • Infiltrate the skin and subcutaneous tissue with around 10 mL of lidocaine 1–2%.

  • Some people like to nick the skin with a small (e.g. no. 11) scalpel blade at the planned point of entry. Alternatively, this can be done once the wire has been passed into the vein.

  • Palpate the line of the carotid artery and insert the needle with syringe attached lateral to this line at an angle of 45° to the skin, aiming for the right nipple area (or anterior superior iliac spine).

  • Advance the needle slowly with some negative pressure on the syringe so that venous blood is withdrawn when the vein is cannulated. The vein is superficial and cannulation should be achieved at a depth of a few centimetres. Do not advance beyond this as the apex of the lung could be injured. Some people initially identify the position of the vein with a small gauge needle before using the needle for cannulation.

  • When venous access is obtained, remove the syringe and pass the wire down through the needle. If the wire does not pass freely then do not force the wire. Withdraw the wire and ensure you can still pull back blood from the needle. It may have moved position.

  • Once the wire is in place remove the needle, nick the skin (if not already done), and pass the dilators over the wire. Then introduce the haemostatic sheath and remove the wire.

Fig. 7.1 Right internal jugular vein cannulation.

Fig. 7.1 Right internal jugular vein cannulation.

Difficult internal jugular access

  • If you accidentally access the carotid artery, firm pressure will be needed for a number of minutes to obtain haemostasis. A large haematoma may make access to the internal jugular difficult.

  • If you cannot get access try an alternative (femoral or subclavian) and consider getting senior help.

Subclavian vein cannulation

The subclavian approach (Figure 7.2) allows access to the patient if the area around the patient’s head is unavailable (e.g. during a cardiac arrest). A line inserted by this route lies on the anterior chest, is comfortable for the patient, and is easy to manage. The main limitations of the approach are a risk of pneumothorax and an inability to apply pressure to the target vessels in the event of multiple venous or inadvertent arterial puncture. The dominant side should be used, keeping the non-dominant side free for possible permanent pacemaker implantation.

  • Prepare and drape the skin. Position patient in slight head-down position.

  • Identify the junction between the medial third and lateral two-thirds of the clavicle (this is usually at the apex of a convex angulation as the clavicle sweeps laterally and cranially).

  • The skin incision point is 2 cm inferior and lateral to this point.

  • Infiltrate the skin and subcutaneous tissue at this point and up to the edge of the clavicle at the first landmark.

  • Move the needle tip stepwise down the clavicle infiltrating local anaesthetic. Keep the needle horizontal until it moves below the clavicle.

  • Prepare the cannulation needle and follow the same initial track as the anaesthetic needle.

  • When the needle lies just below the clavicle swing the needle round to aim at the nadir of the suprasternal notch.

  • Keeping the needle horizontal and parallel to the bed (avoiding lifting the hands off the body and angling the needle tip down) minimizes the risk of pneumothorax.

  • Advance the needle slowly with some negative pressure on the syringe so that venous blood is withdrawn when the vein is cannulated.

  • When venous access is obtained, remove the syringe and pass the wire down through the needle. If the wire does not pass freely then do not force the wire. Withdraw the wire and ensure you can still pull back blood from the needle. (It may have moved position.)

  • Once the wire is in place remove the needle, nick the skin (if not already done), and pass the dilators over the wire. Then introduce the haemostatic sheath and remove the wire.

Fig. 7.2 Right subclavian vein puncture.

Fig. 7.2 Right subclavian vein puncture.

Difficult subclavian access

  • If you have failed to get access on one side do not attempt subclavian access on the other side due to the risk of bilateral iatrogenic pneumothoraces.

  • If you cannot get access try an alternative (femoral or internal jugular) and consider getting senior help.

Femoral vein cannulation

The femoral approach (Figure 7.3) allows easy cannulation of a great vein and is valuable in an emergency setting. The area can be compressed in the event of bleeding and as such is probably the access of choice in the setting of thrombolysis. The main limitations relate to subsequent patient immobility and a probable increased risk of line infection. There is also an increased risk of deep vein thrombosis with a temporary wire in place for a prolonged period.

  • The patient should be lying flat with the leg slightly adducted and externally rotated.

  • Shave the groin, prepare the skin, and drape.

  • Palpate the femoral artery below the inguinal ligament, over or slightly above the natural skin crease at the top of the leg.

  • The femoral vein lies medial to the femoral artery.

  • Infiltrate local anaesthetic at the skin surface over the femoral vein and deeper layers.

  • Ultrasound guidance should be used if available. Advance the cannulation needle at 30–45° to the skin surface. The vein usually lies ~2–4 cm from the skin surface.

  • Advance the needle slowly with some negative pressure on the syringe so that venous blood is withdrawn when the vein is cannulated.

  • When venous access is obtained, remove the syringe and pass the wire down through the needle. If the wire does not pass freely then do not force the wire. Withdraw the wire and ensure you can still pull back blood from the needle. (It may have moved position.)

  • Once the wire is in place remove the needle, nick the skin (if not already done), and pass the dilators over the wire. Then introduce the haemostatic sheath and remove the wire.

Difficult femoral access

  • The femoral vein is often more medial than one thinks.

  • The right femoral is easier to access for most operators.

  • If the guide wire or sheath will not advance, screen at the groin to confirm wire position. It may pass into the contralateral femoral vein or even distally into the leg if the puncture is vertical.

Insertion of rigid pacing electrode

Standard insertion

See Figure 7.4.

  • Under X-ray guidance insert electrode until it sits in the right atrium.

  • From subclavian or internal jugular approaches this is usually straightforward. For a femoral approach, screening of the electrode from the leg may be required to ensure it passes to the right atrium avoiding tributaries within the abdomen. If the lead passes down a tributary it will be seen heading away from the midline or curving over (often into a hepatic tributary under the diaphragm). A small bend on the end of the lead can sometimes make passage easier.

  • Once in the right atrium rotate the electrode until the curved tip is pointing towards the tricuspid valve (to the right on the X-ray).

  • Advance the wire through the tricuspid valve (usually causing ventricular ectopics) until it sits at the apex (right-hand border of the cardiac silhouette).

  • Manipulate the tip of the wire so that it points downwards in the apex (lateral on the X-ray). The final position should resemble a ‘heel of a foot’ in the right atrium when viewed from a superior approach. When approached from the femoral vein the final position will be of a long gentle curve to the apex again pointing downwards.

Fig. 7.4 Position of temporary pacing wire. View of pacing wire in the right ventricular apex from an upper approach (black) and femoral approach (grey). Note the coronary sinus running in the posterior portion of the atrioventricular groove.

Fig. 7.4 Position of temporary pacing wire. View of pacing wire in the right ventricular apex from an upper approach (black) and femoral approach (grey). Note the coronary sinus running in the posterior portion of the atrioventricular groove.

Alternative approaches

  • If unable to cross the tricuspid valve directly, turn the electrode till it is pointing towards the free wall of the right atrium (left on the X-ray). Advance the wire with the tip pressing against the free wall and try to form a loop in the right atrium. This may then spontaneously prolapse across the tricuspid valve. Alternatively, slight rotation of the electrode may flick the tip into the right ventricle.

  • Once in the ventricle manipulate the electrode and aim for the tip to lie in the apex as described above.

Difficult electrode positioning

  • Inadvertent positioning in the coronary sinus results in a lead pointing up and to the patient’s left. Compared to a position in the right ventricular outflow tract (RVOT) on pulling the lead back and rotating it will only follow back in the same line (with a lead in the RVOT it will flop downwards into the cavity of the RV).

  • Sensing in the coronary sinus shows a large P wave and QRS.

  • The tip of most rigid electrodes can be moulded to change the angle of the tip if crossing the tricuspid valve is problematic.

  • If all attempts with a rigid electrode fail, change to a flotation electrode.

  • With severe tricuspid regurgitation the electrode may repeatedly ‘blow’ back into the right atrium. This can be a difficult situation. It may require positioning of a permanent active lead and occasionally the use of a CS sheath (normally used for CRT pacing).

Insertion of flotation electrode

  • Before insertion make sure the balloon is intact by a test inflation (Figure 7.5).

  • Under X-ray guidance, if available, advance the electrode into the right atrium.

  • Inflate the balloon with 1 mL of air and lock into the balloon by turning the tap.

  • Advance the electrode. Ideally the balloon is dragged across the tricuspid valve by blood flow.

  • Once in the right ventricle (RV) deflate the balloon by turning the tap and position the lead in the RV apex as for a rigid electrode.

  • The balloon may float into the RVOT. If this occurs deflate the balloon and pull back slightly so the tip of the electrode slips into the apex.

Fig. 7.5 Flotation temporary pacing electrode with balloon deflated and inflated.

Fig. 7.5 Flotation temporary pacing electrode with balloon deflated and inflated.

Setting up pacing

Connect the lead to the pacing box (Figure 7.6).

Threshold

  • Set the output to 3 V and pace at a rate above the intrinsic cardiac rate.

  • Ensure you have capture of the ventricle. If not, check all your lead connections and that the pacing box is properly powered. If still no capture, reposition your electrode and try again.

  • If there is capture of the ventricle, slowly turn down the box output, watching the ECG monitor.

  • Identify the point where capture is lost. Note the output and then increase the output again until the ventricle is recaptured. The output where the ventricle is recaptured is the pacing threshold.

  • Aim for a threshold of < 1V. If the threshold is higher then go back and reposition the lead. Sometimes it is necessary to accept borderline thresholds but this should be avoided wherever possible.

  • Set output to at least 3× the pacing threshold to ensure a good safety margin.

Stability

Test the stability of the lead position by observing lead motion on the X-ray and checking that the ventricle is still captured on the ECG monitor during deep inspiration and coughing (if the patient is able to comply). If the lead is not stable then reposition the lead (often just by gently advancing it) and re-check threshold and stability.

Fixing

  • Once in a satisfactory position, ensure the lead and sheath are well sutured to the skin to minimize risk of displacement. Apply transparent occlusive dressings over the sheath and lead to help fix them in place and maintain sterility.

  • Secure the external portion of the lead with tape or other fixatives.

  • Fixing a loop on the skin should mean that inadvertent tugs on the wire will tighten the loop rather than pulling out the wire.

Setting the box

  • ‘Output’ should be set to three times the threshold, for example 3 V.

  • Set to ‘demand’ at a ‘rate’ of, for example, 70 bpm.

  • ‘Demand’ will mean it does not pace if intrinsic activity is sensed. Asynchronous pacing is therefore avoided and the risk of inducing ventricular arrhythmias reduced. The pacemaker will, on a beat-to-beat basis, ‘pace’ when it does not detect ventricular activity above that rate and the red ‘pace’ light will illuminate. When the spontaneous ventricular rate is above the pacemaker rate, the box will inhibit and the red ‘sense’ light will illuminate.

  • ‘Sensitivity’ should be adjusted to ensure that each intrinsic beat is detected but that skeletal muscle interference does not lead to pacemaker inhibition (the lower the setting, the more sensitive the pacemaker Temporary cardiac pacing pp. [link][link]).

Complications

These may be related to access, the pacing electrode, the connections, infections, or thromboembolism. The common complications depend on the access site.

Jugular access

  • Carotid artery puncture with haematoma managed with manual compression.

Subclavian access

  • Subclavian artery puncture with haemorrhage.

  • Haemothorax (Temporary cardiac pacing p. [link]).

  • Pneumothorax (Temporary cardiac pacing p. [link]).

Femoral access

  • Venous thrombosis (with long-term wire placement).

  • Increased risk of infection.

  • Increased risk of displacement.

Pacing wire

  • Dislodgement with failed pacing or intermittent pacing.

  • Ventricular arrhythmia due to mechanical irritation of the RV.

  • Fracture of electrode (rare).

  • Perforation of myocardium with pericarditic pain, effusion, tamponade (Temporary cardiac pacing pp. [link][link]). Perforation occurs in up to 10% of procedures in some series, and may only become apparent when the wire is subsequently withdrawn. It is sensible to have a pericardicentesis kit available when the wire is removed.

Other forms of temporary pacing

Transcutaneous pacing

This technique is effective in up to 95% of cases but should be considered a temporary measure until a more definitive form of pacing therapy is available as it is uncomfortable for the conscious patient. Pads are placed in either an antero-posterior or antero-lateral arrangement. Alert patients are likely to require sedation and analgesia due to pectoral muscle contraction.

Dual chamber temporary pacing

An additional atrial J preformed lead may be inserted from the subclavian or jugular approach. This may be required in patients dependent on A-V (atrioventricular) synchrony for satisfactory haemodynamics.

Tunnelled temporary pacing system

This type of system is particularly useful in the pacing-dependent patient requiring explantation of an existing pacemaker system due to infection. A tunnelled single or dual chamber system may be implanted with the leads tunnelled on the front of the chest approximately 5 cm from a subclavian or jugular point of access. These may be connected to a permanent pulse generator taped to the front of a chest and may remain in place for a number of weeks until the patient is ready for a new permanent system.

Epicardial pacing

This is a common form of pacing post cardiac surgery with wires attached directly to the epicardium and passed through the skin (usually in the epigastric region). Although very useful in the immediate post-surgical phase, they suffer deterioration in performance and may become unusable by day 5–10.

Transoesophageal pacing

This route has been proposed for emergency pacing in the conscious patient and requires an electrode to be passed via the oropharynx into the stomach with pacing through the diaphragm. It is rarely used because of the ease of transvenous pacing.

References

1. Lamas GA, Muller JE, Turi ZG, et al. (1986) A simplified method to predict occurrence of complete heart block during acute myocardial infarction. Am J Cardiol 57(15): 1213–19.Find this resource:

2. Gregoratos G, Abrams J, Epstein AE, et al. (2002) ACC/AHA/NASPE 2002 guideline update for implantation of cardiac pacemakers and antiarrhythmia devices: summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/NASPE Committee to Update the 1998 Pacemaker Guidelines). Circulation 106(16): 2145–61.Find this resource: