Temporary cardiac pacing (TCP) is a type of exogenous cardiac pacing in which an external energy source that delivers electrical impulses to stimulate the heart to contract faster than its native rate. This intervention can be used to over-ride a malignant tachydysrhythmia or compensate for symptomatic bradycardia. TCP is typically used for dysrhythmias refractory to pharmacological therapies or cardioversion. Temporary cardiac pacing is not a new intervention; it was first attempted in 1952 when Paul Zoll used hypodermic needles in the chest wall to deliver a pulsating external current for two patients with asystole. Today, TCP is available in a broad spectrum of critical care settings, from pre-hospital to the intensive care unit, delivered via a variety of modalities including transcutaneous, transvenous, epicardial, and transesophageal. This activity will focus on temporary cardiac pacing in critical care settings.
Exogenous cardiac pacing utilizes an external power source to deliver electrical impulses to the myocardium, directly stimulating myocardial depolarization and ventricular (or atrial) contraction and allowing the physician to manipulate the electromechanical conductance of the heart.
In normal physiology, an electrical impulse is generated at the sinoatrial (SA) node, is transmitted through the atrioventricular (AV) node, and then down the His-Purkinje system leading to sequential ventricular depolarization and contraction. In bradydysrhythmias, a variety of pathologic processes can affect any point in the conduction system, leading to an insufficient heart rate and, therefore, cardiac output. When used for bradydysrhythmias, exogenous pacing generates extrinsic electrical impulses that bypass the affected conduction system causing direct ventricular depolarization. The physician can then stimulate ventricular contraction at a rate greater than the native ventricular or junctional rate, increasing cardiac output to meet demand.
In contrast, refractory tachydysrhythmias have varied pathophysiology. In supraventricular tachydysrhythmias, there is often a re-entrant pathway that bypasses the AV node or an ectopic and unregulated pacemaker. Anti-tachycardia pacing (ATP) attempts to correct this by disrupting the re-entrant circuit or over-riding the ectopic pacemaker with an external electrical impulse at a rate of 10 to 20 BPM greater than the native rate, changing the pattern of repolarization. In refractory monomorphic ventricular tachycardia, ATP prevents abnormal ventricular automaticity by changing the pattern of ventricular depolarization and creating more uniform repolarization. In refractory polymorphic ventricular tachycardia, increasing the rate of ventricular depolarization decreases the ventricular refractory period, thereby reducing susceptibility to the R on T phenomenon. Using ATP to override a native dysrhythmia is also called overdrive pacing (ODP).
Temporary transcutaneous pacing (TTCP) uses external pads to transmit an electrical impulse through the skin, subcutaneous soft tissue and chest wall to stimulate ventricular depolarization. Adherent cutaneous pads are used in either the anterior-posterior or anterior-lateral positions, with the former being preferred.
Temporary transvenous pacing (TTVP) uses central venous access, typically via the right internal jugular or left subclavian vein, to pass an electrode into the right ventricle (RV). Electrical impulses are then delivered to the RV endocardium, depolarizing it first, thus resulting in a left bundle branch block (LBBB) pattern on an electrocardiograph (ECG).
Epicardial pacing is most often deployed intraoperatively during cardiac surgery. Pacing electrodes get placed on the epicardium at the right atrium (RA) and RV, or RA and both ventricles.
Transesophageal pacing occurs through placing an electrode in either the mid-esophagus, stimulating the RA, or in the gastric fundus, stimulating the RV through the diaphragm. Transesophageal pacing is not common due to difficult lead placement and patient discomfort.
Temporary cardiac pacing may be indicated for any symptomatic bradydysrhythmia when permanent cardiac pacing is not immediately indicated, unavailable, or too risky, such as severe hemodynamic instability. The most common indication is symptomatic bradycardia due to AV nodal block. There are a variety of reversible causes of bradycardia for which TCP may be indicated, including acute myocardial infarction, electrolyte disturbances, drug toxicity, damage to the intrinsic conduction system during cardiac surgery or valve replacement/repair, cardiac trauma, cardiac abscess, myocarditis, heart transplant, and others. TCP may also be indicated for refractory ventricular tachycardia, electrical storm, or refractory polymorphic ventricular tachycardia. Prophylactically, TCP may be an option for preventing tachydysrhythmias such as atrial fibrillation and atrial flutter following cardiac surgery.
There are no absolute contraindications to temporary cardiac pacing. However, TCP should be avoided or used with caution in certain scenarios. The most common reason to avoid any kind of temporary cardiac pacing is hemodynamically stable bradydysrhythmias with rare or tolerable symptoms. Clinicians should avoid cardiac pacing in hypothermia (unnecessary) and prolonged bradyasystolic arrest (futile). Clinicians should also avoid ransvenous pacing in patients with a prosthetic tricuspid valve, as catheter placement may damage the valve or the catheter may become stuck in the valve, and patients with an excessive risk of bleeding, including those with acute myocardial infarction receiving thrombolytics, anticoagulation and antiplatelet agents.
Temporary transcutaneous pacing requires a pulse generator and monitoring unit with standard defibrillation pads. These are ubiquitous in most medical settings. The pulse generator must have a pacing function. ECG electrodes, non-invasive or invasive blood pressure monitoring, and pulse oximetry are strong recommendations.
Temporary transvenous pacing requires central venous access, typically with a 6 French (Fr) venous percutaneous introducer sheath, a transvenous pacing catheter, and an external pulse generator. Ultrasound guidance for central venous access is also a strong recommendation. A 12 lead-capable ECG machine, cardiac monitor, non-invasive or invasive blood pressure monitoring and pulse oximetry should be available. This procedure is sterile, and standard sterile technique is necessary.
The transvenous pacing catheter is mostly bipolar, 3 Fr to 5 Fr in diameter and 100 cm long. Lines are typically present at 10 cm intervals to estimate catheter depth. Catheters may be flexible, semi-floating, or rigid. For most emergent indications, when temporary pacing would be in order, a semi-floating catheter with a balloon is used. The balloon holds 1.5 ccs of air and requires testing before insertion. The leading end of the catheter has two electrodes, of which the negative is most distal. Adapters allow the electrodes to be attached to the pulse generator.
The external pulse generator delivers an electrical current through the pacing catheter, measured in milliamperes (mA). Generators share the same basic features, including electrical output and cardiac sensing components. These are present as dials on the generator’s face. Output control regulates the current delivered, functionally controlling the ability to obtain electrical capture. Rate control selects the pacing rate. Sensitivity control establishes the threshold at which a sensed intrinsically generated current inhibits the pacemaker from firing. This setting is the choice for demand (synchronous) pacing. For most emergent indications, the sensitivity control is turned to the lowest setting, providing asynchronous (fixed rate) pacing.
Temporary transcutaneous pacing:
Temporary transvenous pacing:
Placement without ECG guidance:
Placement with ECG guidance:
Complications of TTCP include pain, failure to obtain capture, loss of capture, and rarely cutaneous burns. Complications of TTVP are more numerous, and many are related to central venous access, including infection, bleeding, damage to nearby structures, vein thrombosis, air embolism, pneumothorax, and others. Additionally, TTVP can sometimes induce VT or ventricular fibrillation.
Select clinical pearls regarding TCP include:
Temporary cardiac pacing is a potentially life-saving procedure for refractory dysrhythmias that can bridge patients to a destination therapy. However, TCP is not without risks, and a team-based, an interprofessional approach can improve outcomes, decrease adverse events, and increase patient safety. All members of the healthcare team should be aware of the indications for TCP to improve patient selection, therefore reducing the exposure of patients to the risks associated with this procedure unnecessarily. Fostering a culture of open, bidirectional communication may allow all members of the healthcare team to voice their concerns, potentially preventing adverse events.
During TTCP, a team-based approach involving physicians, nurses, and emergency medical technicians (EMTs) is essential for timely deployment. A coordinated approach to defibrillation pad and ECG electrode placement, including rolling the patient for anterior-posterior pad placement, is necessary. After initiating TTCP, nurses should frequently evaluate the patient for pain and communicate their concerns to the provider if additional analgesia or sedation is required. The entire healthcare team should know how to assess for signs of mechanical capture and alert the appropriate provider if a loss of capture is suspected.
Temporary transvenous pacing also requires an interprofessional team-based approach. An interprofessional approach to central venous catheter placement and maintenance has been shown to decrease the complication rate. Similar to TTCP, all members of the healthcare team should frequently evaluate for signs of a loss of capture and alert the appropriate providers if suspected.
Temporary cardiac pacing is a bridge from a variety of diseases to definitive therapy and often requires a an interprofessional approach. Cardiology and electrophysiology specialists should be involved early to prepare for permanent pacemaker placement, percutaneous coronary intervention, or other definitive care. In suspected overdoses, toxicology consultation can guide the initial treatments, provide information on the expected course, and the suitability of a particular poisoning for TCP. In post-cardiac surgery patients, intensive care management by intensivists and cardiothoracic surgeons has been shown to improve outcomes and decrease adverse events. Coordination between the intraoperative and intensive care unit teams regarding epicardial lead placement and intraoperative pacing requirements is essential for a smooth transition of care. Checklists may decrease adverse events related to the transfer of care. With the interprofessional approach, patients can achieve optimal results while experiencing minimal adverse events. [Level 5]
Nurses working in the emergency department, cardiology or the cardiac surgery ward should be familiar with external pacing and indications.
|||Gammage MD, Temporary cardiac pacing. Heart (British Cardiac Society). 2000 Jun; [PubMed PMID: 10814641]|
|||Sullivan BL,Bartels K,Hamilton N, Insertion and Management of Temporary Pacemakers. Seminars in cardiothoracic and vascular anesthesia. 2016 Mar; [PubMed PMID: 26134176]|
|||Harrigan RA,Chan TC,Moonblatt S,Vilke GM,Ufberg JW, Temporary transvenous pacemaker placement in the Emergency Department. The Journal of emergency medicine. 2007 Jan; [PubMed PMID: 17239740]|
|||Kowey PR,Engel TR, Overdrive pacing for ventricular tachyarrhythmias: a reassessment. Annals of internal medicine. 1983 Nov; [PubMed PMID: 6638725]|
|||Blommaert D,Gonzalez M,Mucumbitsi J,Gurné O,Evrard P,Buche M,Louagie Y,Eucher P,Jamart J,Installé E,De Roy L, Effective prevention of atrial fibrillation by continuous atrial overdrive pacing after coronary artery bypass surgery. Journal of the American College of Cardiology. 2000 May; [PubMed PMID: 10807440]|
|||Bektas F,Soyuncu S, The efficacy of transcutaneous cardiac pacing in ED. The American journal of emergency medicine. 2016 Nov; [PubMed PMID: 27461886]|
|||Reade MC, Temporary epicardial pacing after cardiac surgery: a practical review: part 1: general considerations in the management of epicardial pacing. Anaesthesia. 2007 Mar; [PubMed PMID: 17300304]|
|||Carrizales-Sepúlveda EF,González-Sariñana LI,Ordaz-Farías A,Vera-Pineda R,Flores-Ramírez R, Thermal burn resulting from prolonged transcutaneous pacing in a patient with complete heart block. The American journal of emergency medicine. 2018 Aug; [PubMed PMID: 29691105]|
|||Hill PE, Complications of permanent transvenous cardiac pacing: a 14-year review of all transvenous pacemakers inserted at one community hospital. Pacing and clinical electrophysiology : PACE. 1987 May; [PubMed PMID: 2440007]|
|||Pinneri F,Frea S,Najd K,Panella S,Franco E,Conti V,Corgnati G, Echocardiography-guided versus fluoroscopy-guided temporary pacing in the emergency setting: an observational study. Journal of cardiovascular medicine (Hagerstown, Md.). 2013 Mar; [PubMed PMID: 22240748]|
|||Ferri LA,Farina A,Lenatti L,Ruffa F,Tiberti G,Piatti L,Savonitto S, Emergent transvenous cardiac pacing using ultrasound guidance: a prospective study versus the standard fluoroscopy-guided procedure. European heart journal. Acute cardiovascular care. 2016 Apr; [PubMed PMID: 25673783]|
|||Zingg W,Cartier V,Inan C,Touveneau S,Theriault M,Gayet-Ageron A,Clergue F,Pittet D,Walder B, Hospital-wide multidisciplinary, multimodal intervention programme to reduce central venous catheter-associated bloodstream infection. PloS one. 2014; [PubMed PMID: 24714418]|
|||Kumar K,Zarychanski R,Bell DD,Manji R,Zivot J,Menkis AH,Arora RC, Impact of 24-hour in-house intensivists on a dedicated cardiac surgery intensive care unit. The Annals of thoracic surgery. 2009 Oct; [PubMed PMID: 19766800]|
|||Stephens RS,Whitman GJ, Postoperative Critical Care of the Adult Cardiac Surgical Patient. Part I: Routine Postoperative Care. Critical care medicine. 2015 Jul; [PubMed PMID: 25962078]|