SACCM 203: Temporary Cardiac Pacing

Question 1

What are the three types of temporary cardiac pacing?

Answer 1

• transvenous
• transcutaneous
• transesophageal

Question 2

(1) Describe transvenous temporary cardiac pacing, its (2) advantages and potential (3) complications

Answer 2

(1) lead wire inserted via a sheat introducer into either jugular or saphenous vein –> advanced into the right ventricle –> current generated from a pulse generator outside of the body to the lead
(2) Advantages:
* more consistent capture in patients with SA or AV nodal disease
* improved patient comfort
* lower equipment cost (?)
* relative ease of insertion by experienced personnel

(3) Complications:
* lead dislodgement - if patient moves
* bleeding
* thrombosis
* infection
* ventricular arrhythmias
* cardiac perforation

Question 3

What are the advantages of transcutaneous temporary cardiac pacing over other modalities? What are potential complications

Answer 3

Advantages:
* shorter time to implementation (more appropriate in life-threatening situations)
* patch electrodes can be used for other modalities - cardioversion or defibrillation (if patient develops e.g., VF)

Complications:
* discomfort
* musculoskeletal stimulations
–> requires heavy sedation or general anesthesia (disadvantage)

Question 4

Describe transesophageal temporary cardiac pacing, it’s advantages and disadvantages

Answer 4

specialized transesophageal pacing lead introduced into the esophagus just dorsal to the heart
advantage:
* no external muscle sitmulations
* can be implemented more rapidly than transvenous pacing
disadvantages:
* requires GA
* paces the atria not ventricles - not useful in patients with AV nodal disease

complications: focal erosive esophagitis reported in animal study

Question 5

List 6 indications for temporary cardiac pacing

Answer 5

• HR and BP support while patient undergoes anesthesia for permanent pace maker
• HR and BP support in patient with subclinical sinus nodal dysfunction when awake but medically refractory bradycardia under GA - requiring surgery for other indications than permanent pace maker
• hemodynamic stabilization until permanent pace maker can be provided - e.g.,has to wait due to systemic infection or endocarditis
• medically refractory and potentially reversible bradycardia
• cardiac arrest from medically refractory sinus arrest

Question 6

List the steps of transvenous pacing system placement

Answer 6

• depending on patient demeanor - sedation or anesthesia
• aseptically prep either the saphenous or jugular vein
• optional: local lidocaine administration
• aseptically insert a sheat introducer using the Seldinger technique
• flush introducer with heparinized saline
• insert pacing wire through one-way valve of introducer
• advance lead to the right ventricular apex - confirm with echocardiography or fluoroscopy
• set rate to 60-100 beats/min (dog)
• set energy output to 3 mA - then gradually turn down until capture is lost - then set paceaker to at least twice the threshold value
• set sensitivity to 3 mV
• apply triple antibiotic ointment and dress insertion site

Question 7

List the steps of transcutaneous cardiac pacing

Answer 7

• need defibrillator/ecg system that has a pacing option
• connect the standard ecg leads to the patients foot pads
• shave fur on the left and right hemithorax over the precordial impulse
• place the pacing patch electrodes on left and right hemithorac using small amount ECG paste
• can further secure patches using nonadhesive bandage material
• adjust lead selection and ecg gain until good ECG recorded
• confirm accurate QRS sensing by the appearance of sensing marker on the ECG monitor
• chose desired pacing rate
• increase pacing current gradually until ventricular capture identified on ECG (wide QRS-T after pacing spike)
• confirm ventricular capture by audible doppler or pulse palpation
• set current output just above capture threshold (~10-20mA higher)

Question 8

List the steps of transesophageal cardiac pacing

Answer 8

• patient in lateral recumbency under general anesthesia
• guide pacing catheter transorally through a rigid plastic guide (e.g., tubing of stethoscopy) into the esophagus - connected to pulse generated - advance to level of diaphragm - note pacing of diaphragm
• then gradually pull back until atrial pacing noted on the ECG
• set pulse width initially to 2-10 ms and pacing amplitude at 20-30 mA
• gradually lower pacing amplitude to lowest level achieving consistent pacing