The Journal of , Vol. 32, No. 1, pp. 105–111, 2007 Copyright © 2007 Elsevier Inc. Printed in the USA. All rights reserved 0736-4679/07 $–see front matter doi:10.1016/j.jemermed.2006.05.037

Technical Tips

TEMPORARY TRANSVENOUS PACEMAKER PLACEMENT IN THE EMERGENCY DEPARTMENT

Richard A. Harrigan, MD,* Theodore C. Chan, MD,† Steven Moonblatt, MD,* Gary M. Vilke, MD,† and Jacob W. Ufberg, MD*

*Department of Emergency Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, and †Department of Emergency Medicine, University of California, San Diego Medical Center, San Diego, California e Abstract—Emergency Department placement of a tem- patient management in the ED—depending upon patient porary transvenous cardiac pacemaker offers potential life- stability—placement of a transvenous cardiac pacemaker saving benefits, as the device can definitively control (TVP) usually is performed after other less invasive rate, ensure effective myocardial contractility, and provide means of treatment (e.g., pharmacologic, treating the adequate cardiac output in select circumstances. The pro- cedure begins with establishment of central venous access, underlying cause, transcutaneous pacing) have been ex- usually by a right internal jugular or left subclavian vein plored and exhausted. approach, although the femoral vein is an acceptable alter- Although a variety of pacemaker modalities exist— native, especially in patients who are more likely to bleed transesophageal, epicardial, endocardial, transcutaneous, should vascular access become complicated. The indica- and transvenous—it is the latter two methods that have tions for the procedure, as well as the equipment needed, applicability in the ED. Transcutaneous pacing, which is are reviewed. Both blind and ECG-guided techniques of usually employed initially as a temporizing measure, will insertion are described. Methods of verification of pace- not be discussed here. Transvenous pacing, which involves maker placement and function are discussed, as are the placing a catheter-based electrode into the right side of the early complications of the procedure. © 2007 Elsevier Inc. heart, is actually two procedures in one: establishing central e Keywords—transvenous pacemaker; cardiac pacemaker; venous access, and then introducing and directing the elec- cardiac procedures trode through the venous system into the heart. Placement of a TVP involves placement of the electrode into the right with the goal of pacing the endocardium in a VVI INTRODUCTION mode (Ventricle-paced, Ventricle-sensed, Inhibited sensing response). This is the least complicated approach to rees- Temporary cardiac pacing may be instituted in the Emer- tablishing effective cardiac depolarization, and it allows the gency Department (ED) for a variety of indications via physician to pace the heart either asynchronously or in a several different modalities. The goal of temporary car- demand mode, wherein the pacemaker is inhibited when a diac pacing is to restore effective cardiac depolarization native impulse is sensed. and myocardial contraction, resulting in the delivery of This review will focus on the indications for TVP adequate cardiac output. Whereas consideration of tem- placement and describe the two common ways the pro- porary cardiac pacing may begin early in the course of cedure may be performed in the ED—blindly and with

Technical Tips is coordinated by Gary M. Vilke, MD, of the University of California, San Diego, San Diego, California and Richard A. Harrigan, MD, and Jacob W. Ufberg, MD, of Temple University, Philadelphia, Pennsylvania

RECEIVED: 20 October 2004; FINAL SUBMISSION RECEIVED: 3 November 2005; ACCEPTED: 31 May 2006 105 106 R. A. Harrigan et al.

Table 1. Indications for Emergent Transvenous Pacemaker generator. In addition, an ECG machine and cardiac Placement (1–3)* monitor should be available. Several pre-packaged trays Bradydysrhythmias are available that contain the introducer sheath, pacing Symptomatic catheter, and other equipment necessary for pacemaker Sinus arrest Sinus insertion. Symptomatic The external pacing generator is used to deliver the Second degree atrioventricular block, Mobitz type II electrical current, measured in milliamperes (mA), Third degree (complete) atrioventricular block Symptomatic drug overdose through the pacing catheter. Various available generators Tachydysrhythmias share the same basic features (Figure 1). The pacing Overdrive pacing of rhythms refractory to medical generator has electrical output and cardiac sensing com- management ponents, which are usually present as dials on the face of * The indications are listed with the assumption that: 1) less invasive the generator. An output control dial allows for regula- means (e.g., pharmacologic agents and antidotes, transcutaneous tion of the current, usually from 0.1 to 20 mA. This cardiac pacing) have been tried without success or that success is judged to be short-lived; or 2) the patient is experiencing principally determines the ability of the pacemaker to profound symptomatology (e.g., severe chest pain, dyspnea, or “capture” the heart. A rate control dial selects the pacing altered state of consciousness; hypotension; ; pulmonary rate. The pacing generator also has a sensitivity control edema; or acute ). that establishes a threshold, based on the amplitude of the native R wave, required to suppress the pacemaker from firing. Turning the sensitivity control down will lead to electrocardiographic (ECG) guidance. Confirmation of fixed rate, or asynchronous, pacing, wherein the pace- placement and function will be discussed, and commonly maker fires regardless of the patient’s underlying rhythm. encountered complications will be reviewed. Increasing the sensitivity in concert with modifying the rate control will eventually lead to demand, or synchro- INDICATIONS AND CONTRAINDICATIONS nous, pacing. This occurs when the pacing generator senses intrinsic cardiac activity and inhibits the TVP Various authorities differ slightly when defining the in- from firing. In demand mode, the pacemaker senses the dications for placement of a TVP (1–3). Indications can patient’s underlying ventricular rate and will not fire as be viewed with several constructs in mind: emergency long as the patient’s rate is equal to or faster than the rate vs. prophylactic pacemaker placement; treatment of bra- set on the pacing generator (2,3). dydysrhythmias vs. tachydysrhythmias; and in patients Various transvenous pacing catheters are available experiencing acute myocardial infarction vs. those who with basic similarities. Most are bipolar, 3 Fr to 5 Fr in are not. Table 1 lists standard emergent indications for size, and approximately 100 cm in length (3). Lines TVP placement, and Table 2 depicts commonly accepted marked at 10-cm intervals on the catheter surface can be prophylactic indications for the procedure. In most emer- used to estimate catheter position. Catheters are classi- gent circumstances, a transcutaneous pacemaker is uti- fied as flexible, semifloating, or rigid/non-floating cath- lized initially while the patient is prepared for TVP eters. The latter group carries a higher risk of cardiac placement. Transvenous pacing, and in fact pacing in perforation, and thus they are generally used only under general, does not seem to be beneficial in asystolic/ fluoroscopic guidance, where their stiffness yields the bradyasystolic , traumatic cardiac arrest, or benefit of easier manipulation (1). In emergency situa- in patients with profound and bradydys- tions, a semifloating catheter with or without a balloon rhythmias (3,4). In the latter group, aggressive treatment tip is used most commonly (1–3). In the patient in of the underlying condition is paramount, due to the cardiac arrest, inflating the balloon carries no benefit, as theoretic concern that introducing a pacing wire into a hypothermic patient may precipitate terminal dysrhyth- mias. However, in-hospital cardiac arrest victims with Table 2. Indications for Prophylactic Transvenous complete heart block or bradycardia (not those with Pacemaker Placement (1–3) ) may receive some benefit from transvenous Acute myocardial infarction (especially anterior distribution) pacing unresponsive to pharmacotherapy (5). and Symptomatic sinus node dysfunction Second degree atrioventricular block, Mobitz type II Third degree atrioventricular block EQUIPMENT New left, right, or alternating bundle branch block New The equipment needed to insert a TVP includes an in- Symptomatic patient secondary to failure of permanent pacemaker troducer sheath, pacing catheter, and external pacing Temporary Transvenous Pacemaker 107

there is no forward flow of blood to guide an inflated balloon through the venous system into the right side of the heart. The balloon holds approximately 1.5 cc of air and should be tested for air leak before insertion. At the leading end of the catheter are two electrodes, one of which is marked negative and lies distally. Adapters are supplied in the kit to allow the electrodes to be attached to the pacing generator or to an ECG lead (Figure 2). The introducer sheath is used to establish central venous access. The sheath allows for passage of the pacing catheter into the vein and must be at least one size larger than the pacing catheter. Some sheaths will con- tain an additional port for administration of intravenous fluids or medications.

PLACING THE TRANSVENOUS PACEMAKER Preparation and Site Selection

Once all the equipment is available, the patient is prepped in the usual sterile fashion. A wide area should be cleaned and the patient generously draped to ensure that all the equipment remains in a sterile field. Choosing a central venous access site may depend on physician preference and experience. Options include the internal jugular, subclavian, femoral, or brachial veins. The right internal jugular and the left subclavian veins Figure 1. Pacemaker generator. (A) Pacing indicator. (B) are often preferred, having demonstrated the highest Sensing indicator. (C) Rate control knob. (D) Pacing output control knob. (E) Sensitivity control knob. (F) On/off control. rates of proper placement in code situations; these routes (G) Adaptor for connection to pacing electrode. allow for smooth and direct placement, taking advantage of the natural curve of the pacing catheter (2,3). The right

Figure 2. Transvenous pacemaker catheter. (A) Catheter tip with balloon; (B) balloon inflation port; (C) negative electrode; (D) positive electrode; (E) adapters to attach electrodes to external pacing generator; (F) alligator clip to attach negative electrode to ECG V lead; and (G) syringe for balloon inflation. 108 R. A. Harrigan et al. internal jugular provides the most direct route to the right any of the precordial (V) leads on the ECG machine ventricle and is associated with the lowest complication using an alligator clip. The rest of the leads should be rate (6). If the patient is anticoagulated or has received connected to the patient in the usual fashion. Progres- thrombolytics, the internal jugular or subclavian routes are sion of the catheter can be marked by recognition of char- not recommended due to poor compressibility of the vas- acteristic waveforms; the magnitude and polarity of these cular structures. In this case, establishing femoral venous waveforms are subject to change as the catheter moves access is more appropriate. The brachial vein is rarely used, through the heart (Figure 3). as the catheter is easily dislodged and the site is associated Superior vena caval location results in low ampli- with a higher risk of infection and thrombosis (1–3). tude P waves and QRS complexes, both with a nega- tive polarity as the sensing electrode lies above the heart, with atrial and ventricular depolarization vec- Insertion Techniques tors directed (generally) downward and to the left— away from the catheter. As the catheter tip enters the After central venous access is obtained and the intro- right , the P wave becomes larger (indeed larger ducer sheath is secured in place, the TVP can be than the QRS complex due to the tip’s closer proxim- inserted using either ECG guidance or blindly. Many physicians prefer the blind technique because it is ity to the native atrial pacemaker), and both the P wave faster and technically less complex. To perform the and the QRS complex are initially negative. However, blind procedure, the catheter electrodes are connected the P wave will become biphasic and then positive as directly to the pacing generator. The catheter is then the catheter passes down through the right atrium and inserted and the pacing generator turned on. If the the tricuspid valve. Right ventricular entry is signaled patient has a pulse, the balloon can be inflated once it by a small positive P wave followed by a deeply has passed through the introducer sheath, approxi- negative QRS complex. When the tip of the catheter mately at the 20-cm mark on the catheter; otherwise, engages the right ventricular endocardium, the QRS the catheter can be advanced with the balloon down. complex will show a current of injury with ST seg- The pacing generator is set with the output to the ment elevation. If the catheter exits the right atrium maximal current, the pacing rate to between 60 and 80 into the inferior vena cava, the P wave should maintain beats/min, and the sensitivity to the lowest level (com- a positive polarity while the QRS complexes lose pletely counterclockwise or asynchronous). As the amplitude as the catheter courses further away from catheter is advanced, the ECG monitor placed on the the heart. This would be the same pattern noted if the patient will usually show pacemaker spikes. When the femoral approach were used, but in this case it would catheter enters the right ventricle and makes contact precede the right atrial tracing. If the catheter traverses with the endocardial wall, a left bundle branch block the right ventricle and strays into the pulmonary ar- pattern (e.g., wide QRS complex) should be seen after tery, the P wave will again become negative as the every pacemaker spike (if a right-sided V lead is catheter tip travels above the atria, and the QRS com- used), indicating capture. If the balloon was up, it can plex will become smaller due to the increased distance now be deflated and the catheter secured in place. Although from the right ventricle (7). If a balloon tip catheter is blind insertion can be performed relatively quickly, the employed, the balloon should be inflated when the operator receives virtually no feedback as the catheter is catheter tip enters the right atrium and deflated when advanced—this being the major drawback of this technique passing through the tricuspid valve, as this should help (1–3). guide the catheter toward its ideal destination within the right ventricular apex. Migration toward the right Placement with ECG Guidance ventricular outflow tract and favored by forward flow will thus hopefully be avoided (1–3). Placement with ECG guidance makes use of the TVP Once the catheter is in position, it should be discon- catheter’s sensing function and allows the physician to nected from the ECG machine and attached to the pacing monitor the progression of the catheter as it ap- generator. As with the blind technique, the pacing generator proaches the right ventricle by analyzing the various is then set with maximal current output, a pacing rate in the waveforms that appear as the catheter is advanced. range of 60 and 80 beats/min, and the sensitivity to the The pacing catheter serves as an intracardiac ECG lowest level (asynchronous). A left bundle branch block lead that localizes the position of the tip of the cath- pattern should be seen after every pacer spike on a surface eter. This technique requires that the negative (distal) ECG, indicating capture. If complete capture does not oc- electrode from the end of the catheter be attached to cur, the TVP catheter needs to be repositioned. Temporary Transvenous Pacemaker 109

Figure 3. ECG recordings from within the right heart during transvenous pacemaker placement. (A) High right atrium; (B) mid-to-low right atrium; (C) low right atrium-to-tricuspid annulus; (D) right ventricle; (E) contact with right ventricular endo- cardium; and (F) surface ECG demonstrating pacemaker capture. Reprinted with permission from (2): Wald DA. Therapeutic procedures in the emergency department patient with acute myocardial infarction. Emerg Med Clin North Am 2001;19:451–67.

Verification of Placement right atrial catheter placements. The left subclavian ap- proach, used in six cases, led to two right ventricular and Chest radiography should be performed to verify posi- three inferior vena cava placements, and one right atrial tioning after the TVP is secured, as well as to exclude placement (8). iatrogenic pneumothorax secondary to placement of a Proper placement can be further verified by the 12- central venous line in the thorax if the subclavian or lead ECG. Right ventricular apical location will manifest internal jugular approaches are employed. The catheter as a left-bundle-branch-like pattern on the ECG, with the tip should be located ideally in the right ventricular apex. exception that there is usually precordial QRS complex A portable anteroposterior chest X-ray study is most concordance in a negative polarity (Figure 4), whereas a commonly used, and the catheter tip should be visualized true left bundle branch pattern features QRS complex at the anterior-inferior aspect of the cardiac shadow, transition from negative to positive polarity in the mid- usually slightly to the left of the thoracic spine. If proper precordial leads. The tracing will also feature a leftward placement is in question, a cross-table lateral view sug- frontal plane QRS axis deviation as the pacemaker-gen- gests right ventricular apex placement when the catheter erated impulse emanates from the right ventricular apex tip overlies the inferior aspect of the cardiac shadow and and travels leftward and superiorly. points toward the sternum. One study using radiography to determine catheter placement after blind insertion in the ED found the right atrium to be the most common Verification of Function site of catheter misplacement, occurring in 50% of cases, due to both insufficient advancement as well as coiling Pacing (output) thresholds and sensing thresholds need within the right atrium. Successful placement in the right to be tested after the operator has demonstrated pacing ventricle (10 of 36 cases) was significantly more likely if capture; the latter threshold only pertains to those pa- an internal jugular approach was used. Interestingly, tients who have some sort of underlying rhythm to sense. two-thirds of TVP catheters in this study were placed via The pacing threshold is the minimum current needed to the less-preferred right subclavian vein approach, which obtain capture. To determine this, the pacing generator is may have contributed to the high rate of improper posi- set to a high level of current output, and the pacing rate tioning—as this approach accounted for 16 of the 18 to between 60 and 80 beats/min, or at least 10 beats/min 110 R. A. Harrigan et al.

Figure 4. 12-Lead ECG demonstrating ventricular paced rhythm. Note the characteristic wide-QRS complexes preceded by narrow pacemaker spikes (arrows). The right precordial leads (V1–V3) resemble the classic left bundle branch block pattern, yet the left precordial leads (V4–V6) differ from this classic pattern in that the QRS complexes maintain a principally negative deflection. Also note the leftward frontal plane QRS axis deviation. above the native rate, if one exists. The output is then A more recent advance in the emergent placement of slowly reduced until capture is lost. This test is repeated transvenous pacemakers in the ED has been the use of several times to verify this threshold value. The current bedside ultrasound guidance. Ultrasound imaging pro- should then be set to roughly 2–2.5 times the threshold to vides real-time visualization of the passage of the pacing ensure capture. The ideal pacing threshold is Ͻ 1 mA, so wire into the right ventricle, and can demonstrate contact the pacing output is usually set to no more than 2–3 mA; of the pacing wire with the right ventricular myocardium. the catheter should be repositioned if this threshold is Ultrasound may also be used to verify positioning of above 5–6 mA (1–3). blindly placed pacing wires, and to detect complications The sensing threshold needs to be tested only if the of this procedure such as interventricular septal perfora- pacemaker is going to be used in the synchronous or tion (9,10). demand mode; i.e., if the patient has an underlying Most commonly, a 3.5-MHz linear array probe is used rhythm to be “sensed.” To test the sensing threshold, the in the subcostal (also known as subxiphoid) position. The rate is set to about 10 beats/min below patient’s intrinsic subcostal view is preferred, as it allows excellent views rate and the sensitivity dialed clockwise to the highest of all four cardiac chambers as well as cardiac wall value (demand mode). With these settings, the pace- motion. This position also does not interfere with neces- maker should not be firing, only sensing, as indicated by sary monitoring equipment such as transcutaneous pac- the flashing of the sensing light and the absence of paced ing pads or ECG leads. The pacing wire appears as a beats. The sensitivity is then dialed counterclockwise and bright linear hyperechoic structure as it enters the heart, lowered until the pacer starts firing again. This value is and can be followed as it traverses the tricuspid valve the sensing threshold. The sensitivity control should then into the right ventricle and contacts the myocardium of be lowered to below the sensing threshold to ensure the right ventricular apex. Capture is quite apparent adequate sensing, and to ensure that inappropriate stimuli sonographically as the rhythmic contraction of the heart such as T waves, artifact, and muscle twitches are not can be seen at the pacing rate. “oversensed” by the unit, resulting in inappropriate sup- Two small case series have described success using pression of the pacemaker (1,2). ultrasound assistance for the placement of transvenous Temporary Transvenous Pacemaker 111 pacemaker wires (9,11). The study by Aguilera docu- right ventricle via central venous access, and then stim- mented successful placement of tranvenous pacemaker ulating that electrode and the heart with an external wires using ultrasound guidance in 8 of the 9 patients (89%) pacing generator to optimize cardiac output. In the Emer- in whom it was attempted, a huge improvement over pre- gency Department, the procedure can be performed ei- viously reported success rates as low as 10% (8,9). ther blindly or with ECG guidance. After placement, the TVP must be tested to ensure adequate capture of the myocardium, as well as to assess its sensing abilities if a COMPLICATIONS native rhythm remains. Complications of the TVP can be classified as those related to the various phases of the procedure. First, obtaining central venous access carries the risk of arterial REFERENCES puncture, pneumothorax, and infection as the most com- monly encountered complications, as well as the more 1. Jafri SM, Kruse JA. Temporary transvenous cardiac pacing. Crit unusual, including air embolism, venous thrombosis and Care Clin 1992;8:713–25. 2. Wald DA. Therapeutic procedures in the emergency department thrombophlebitis, and catheter/guidewire looping and patient with acute myocardial infarction. Emerg Med Clin North entrapment. Next, there are the risks associated with Am 2001;19:451–67. right-heart catheterization. These include dysrhythmias, 3. Bressman ES. Emergency cardiac pacing. In: Roberts JR, Hedges th failure to capture, failure to sense, and oversensing. JR, eds. Clinical procedures in emergency medicine, 4 edn. Philadelphia, PA: Saunders; 2004:283–304. Furthermore, the catheter may be misplaced, such as in 4. Syverud SA, Dalsey WC, Hedges JR. Transcutaneous and trans- the coronary sinus, clues to which include an unexpect- venous cardiac pacing for early bradyasystolic cardiac arrest. Ann edly high pacing threshold, failure to capture, a right Emerg Med 1986;15:121–4. 5. Hazard PB, Benton C, Milnor P. Transvenous cardiac pacing in bundle branch block ECG pattern despite right ventric- cardiopulmonary resuscitation. Crit Care Med 1981;9:666–8. ular placement, and a posteriorly directed catheter on 6. Hynes JK, Holmes DR, Harrison CE. Five-year experience with lateral chest X-ray. The catheter may perforate the sep- temporary pacemaker therapy in the coronary care unit. 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Pace 1982;5:222–7. (6,12,13). The number of complications has been demon- 11. Macedo W, Sturmann K, Kim JM, Kang J. Ultrasonographic strated to increase the longer the catheter stays in place (6). guidance of transvenous pacemaker insertion in the emergency Failure to capture or failure to sense are relatively common department: a report of three cases. J Emerg Med 1999;17: 491–6. complications, occurring in 37–43% of cases (12,13). 12. Lumia FJ, Rios JC. Temporary transvenous pacemaker therapy: an analysis of complications. Chest 1973;64:604–8. 13. Austin JL, Preis LK, Crampton RS, et al. Analysis of pacemaker SUMMARY malfunction and complications of temporary pacing in the coro- nary care unit. Am J Cardiol 1982;49:301–6. 14. Wang HE, Sweeney TA. Subclavian central venous catheterization TVP placement is a potentially life-saving procedure that complicated by guidewire looping and entrapment. J Emerg Med involves placing a catheter-based electrode within the 1999;17:721–4.