Cardiology In Critical Care


PURPOSE: To provide guidance for nurses assisting during the insertion of a transvenous pacemaker.



Transvenous pacing catheter                                                      EKG machine
Pacemaker generator with battery and cable                              Alligator clamps
Introducer kit                                                                            Emergency crash cart
Lidocaine                                                                                  Defibrillator
(2) 5cc syringe with 22 and 25 gauge needles                             External Pacer
Sterile gown, gloves, mask


Pacemaker catheters can be placed at the patient's bedside using a "blind' or EKG directed technique. The "blind" technique is used on the patient without and intrinsic rhythm. The EKG directed technique is used with the patient who has an intrinsic rhythm. During the insertion the electrode is advanced under EKG monitoring.


Left Subclavian (most reliable)                                                     Femoral vein
Internal jugular (lower incidence of pneumothorax)                       Brachial vein


Bleeding tendencies and anticoagulation are relative contraindications to all central venous approaches. Severe lung disease and positive end-expiratory pressure ventilation are relative contraindications to internal jugular and subclavian entries.




1. Check that patient has a patent IV, and that the defibrillator, emergency cart and appropriate medications are available. 1. This is an emergent procedure. Venous access, emergent equipment and drugs have a high probability of use.
2. Counsel patient and family and allow for ventilation and questions; obtain consent (time permitting). 2. Time is needed for coping; relieves anxiety; promotes cooperation.
3. Wash and dry insertion site; clip hair if necessary. 3. Prepare site for dressing.
4. Obtain vital signs and ECG rhythm strip prior to insertion. Connect to 12 lead EKG and continuously monitor before, during and after. 4. Establish baseline parameters. This will assist in monitoring for changes and complications.
5. Prepare according to central line insertion checklist. 5. IAW Infection Control Manual.
6. Prep selected site IAW central line insertion checklist. 6. Reduce risk of infection.
7. Anesthetize the area locally. 7.. Reduce pain from insertion.
8. Prepare the external temporary generator:
  1. Insert new battery.
  2. Turn the mA to 6.
  3. Turn rate control to ten beats above the patient’s rate.
  4. Turn sensitivity dial fully clockwise.
8. The rate set above the patient’s a rate will suppress the patient’s natural pacemaker.
9. Connect the alligator clamp, one end to the V1 EKG lead and the other to the distal or negative electrode wire of the pacemaker catheter. 9. This electrode serves as an exploratory intracavitary lead and resulting EKG waveform helps to ascertain electrode position.
10. Monitor patient while physician inserts pacing electrode. 10. The EKG pattern is distinctive when the pacing electrode is in the vena cava, right atrium and right ventricle.


The following EKG findings indicate electrode position:

  • Vena Cava
  • Right Atrium
  • Coronary Sinus
  • Right Ventricular
  • (Out flow tract)
  • Right Ventricular Apex
Lead V1:
  • Small inverted p
  • Tall biphasic p
  • Positive QRS with rabbit ears
  • Negative QRS
  • LBBB, Negative QRS
  • Same
  • Same
  • Positive or neg QRS
  • Positive QRS
  • Left Axis/ pattern of injury (elevated ST)

Portable Chest X-ray is required to confirm placement.

NOTE: Insertion of a pacemaker during a cardiac arrest (asystole) requires connecting the pacing wire to the generator and setting the stimulation threshold to maximum or 20 mA, and an arbitrary rate of 70 bpm. The electrode is then advanced blindly while one scans the EKG for evidence of ventricular capture.




1. After contact between pacing electrode and the right ventricular endocardium is established, assist the physician in connecting to pacemaker generator. Set according to physician’s orders.

Obtain a 12 Lead EKG.

For all Methods of Temporary Pacing

A. Determine the stimulation threshold:

  1. Set pacing rate above patient’s intrinsic rate.
  2. Gradually decrease output (mA) from 20 mA until capture is lost.
  3. Gradually increase output (mA) until capture is established. This is the stimulation threshold.
  4. Set output (mA) at least 1.5 to 2 times higher than the stimulation threshold. This output setting is sometimes referred to as the maintenance threshold.

B. Determine the sensitivity threshold:

  1. Set rate at least 10 beats per minute below patient’s intrinsic heart rate.
  2. Set sensitivity control to most sensitive setting (fully demand or lowest numerical setting). Sensing indicator light should flash with each intrinsic R wave.

C. Set the pacemaker rate, output (mA), and sensitivity (demand or asynchronous), as prescribed or as determined by threshold testing.

D. Assess rhythm for appropriate pacemaker function:

  1. Capture: is there a QRS complex for every ventricular pacing artifact?
  2. Rate: is the rate at or above the pacemaker rate if in the demand mode?
  3. Sensing: does the sensitivity light indicate that every QRS complex is sensed?
1. The physician sets the parameters; must generate a written order for its use.

Establish a baseline.

The output dial regulates the amount of electric current (mA) that is delivered to the myocardium to initiate depolarization. Ventricular pacing (stimulation threshold) should be established at less than 1 mA output whenever possible. The maintenance threshold is set at 1.5 to 2 times above the stimulation threshold to allow for increases in stimulation threshold without loss of ventricular capture.

Sensitivity threshold is the level at which intrinsic ventricular activity is recognized by sensing electrodes. For demand pacing, the sensitivity must be measure and set.

Sensitivity threshold is set at maximum and is lowered only if pacer is sensing inappropriately. If set too high, it will result in sensing P or T as an R wave; if set too low, it results in asynchronous pacing (nonsensing).

Determined by patient’s response. A-V interval (similar to intrinsic PR interval) should be set for optimal ventricular filling, usually between 150 to 250 ms.

ECG tracing should reflect appropriate response to pacemaker settings if pacemaker is functioning properly.

2. Ensure the pacing wire is secured as it exists the introducer; check all connections as well as battery and control settings at least q.4 hrs and document. 2. Prevent migration of wires; these connects are easily disconnected and may result in cardiac arrest. Protects setting from being inadvertently being altered.
3. Maintain site care per Infection Control Manual SOP on central lines. 3. This is a central line with potential for sepsis.
4. Keep the pulse generator dry and the controls protected from mishandling. 4. Moisture will cause pacemaker malfunction; improperly set controls can cause cardiac irritability resulting in dysrhythmias and cardiac arrest.
5. Protect the patient from electromicroshock and electromagnetic interference (EMI):
  1. Cover exposed wires with gloves or tape.
  2. Enclose pulse generator in rubber glove.
  3. Wear rubber gloves when handling exposed wires.
  4. Avoid any nurse-patient contact with electrical apparatus.
  5. Check for ungrounded electrical equipment.
  6. Keep dressing over wires dry and intact when not in use.
5. Electromicroshock and EMI can cause the pulse generator to fail.
6. Monitor patient for complications. Restrict patient mobility depending on insertion site. 6. All invasive procedures have a percentage of complications that can be prevented by an astute nurse.
7. Document location, type of pacing, pacing mode, stimulus threshold, sensitivity setting, pacing rate and intervals, intrinsic rhythm, and percent of pacing. Post sample tracings. 7. Proper documentation assists in the care of the patient and early recognition and prevention of complications.

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This page last updated 07/25/10