safety margin for transcutaneous pacing safety margin for transcutaneous pacing

2008 Feb. 15(1):110-6. Symptomatic clinically significant bradycardias, Don't just treat a number. External transcutaneous pacing has been used successfully for overdrive pacing of tachyarrhythmias; however, it is not considered beneficial in the treatment of asystole. Lee KL, Lau CP, Tse HF, et al. Add 2 mA or set the output 10% higher than the threshold of initial electrical capture as a safety margin. Consider sedation for conscious patients unless they are unstable or deteriorating rapidly and pacing should not be delayed, turn on pacer and set the demand rate to approx. Her shirt is damp. Transcutaneous pacing can be painful and may fail to produce effective mechanical capture. Check to ensure the patient has mechanical capture ( Do not asses the carotid pulse for confirmation; electrical stimulation causes muscle jerking that may mimic the carotid pulse) . Set the output 2 mA above the dose at which consistent mechanical capture is observed as a safety margin . This website also contains material copyrighted by 3rd parties. Transcutaneous pacing is noninvasive and can be performed by ECC providers at the bedside. Cardiac intensive care. 2021 Aug 29. Electric current is delivered between the pacing/defibrillation pads on the patient's chest. 1. 2023 ACLS Medical Training, All Rights Reserved. [QxMD MEDLINE Link]. Christian Schroder How to determine paccing threshold? ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: executive summary. 2020 Dec. 31(12):3277-85. [15]. endstream endobj 128 0 obj <>stream Please try after some time. Normal action potential of myocyte and main ion channels that play major roles in different phases of action potential. The equipment shown is courtesy of Zoll Medical Corp. You may be trying to access this site from a secured browser on the server. . [QxMD MEDLINE Link]. [PMID:8558949], 3. Know that the patient may become more alert whether capture is achieved or not. The patients blood pressure subsequently increased to 90 mmHg.. If still no ventricular capture is achieved further attempts to reposition the TPW should be made. Ramin Assadi, MD Assistant Professor of Medicine, Division of Interventional Cardiology, University of California, Los Angeles, David Geffen School of Medicine In the ICU the patient remains dangerously hypotensive in spite of dobutamine and levophed drips. External transcutaneous pacing has been used successfully for overdrive pacing of tachyarrhythmias; however, it is not considered beneficial in the treatment of asystole. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in If your employer verifies that they will absolutely not accept the provider card, you will be issued a prompt and courteous refund of your entire course fee. Transcutaneous lead implantation connected to an externalized pacemaker in patients with implantable cardiac defibrillator/pacemaker infection and pacemaker dependency. 117(21):e350-408. However, she is still non-verbal and does not follow commands. [Full Text]. 1989 Nov. 12(11):1717-9. 2016 Nov. 34(11):2090-3. J Emerg Med. Malden: Blackwell Publishing; 2005. Modern external pacemakers use longer pulse durations and larger electrodes than the early models did. (Threshold is the minimum current needed to achieve consistent electrical capture.) 3 months ago 2013 Aug. 15(8):1205-9. Sign up with your email address to receive updates and new posts. 2007 Apr. Tell him it involves some discomfort, and that you'll administer medication as ordered to keep him comfortable and help him relax. [Guideline] Epstein AE, DiMarco JP, Ellenbogen KA, et al. There are many reasons why medical professionals often fail to achieve true electrical and mechanical capture. J Endovasc Ther. Studies have demonstrated that more than 90% of patients tolerate pacing for 15 or more minutes. For pacing readiness in the setting of AMI as follows: New left, right, or alternating bundle branch block or bifascicular block, Bradycardia with symptomatic ventricular escape rhythms. Inspection and repositioning as needed can alleviate these problems. Accessed: October 28, 2021. [QxMD MEDLINE Link]. Sherbino J, Verbeek PR, MacDonald RD, Sawadsky BV, McDonald AC, Morrison LJ. muscle artifact). Resuscitation. [QxMD MEDLINE Link]. The patient's blood pressure improves slightly to 84/47 (confirmed by auscultation). Bernstein AD, Daubert JC, Fletcher RD, Hayes DL, Luderitz B, Reynolds DW, Schoenfeld MH, Sutton R. The revised NASPE/BPEG generic code for antibradycardia, adaptive-rate, and multisite pacing. 1999;17:10071009. Some error has occurred while processing your request. Finally, do not be fooled by the monitor into believing that the appearance of QRS complexes means that the patients heart has been captured and is delivering a sustainable blood pressure! Bektas F, Soyuncu S. The efficacy of transcutaneous cardiac pacing in ED. On arrival at the hospital the patient is transitioned to transvenous pacing. ATRIAL THRESHOLD 11(6):656-61. Ventricular fibrillation would necessitate a different treatmentthe definitive therapy is immediate defibrillation. The website authors shall not be held responsible for any damages sustained from the use of this website. [Some need treatment and some dont eg a well conditioned athelete]. We respect your privacy and will never share your email. Do not be fooled by skeletal muscle contraction! hbbd```b``&@$ZzD`O`)d+0H2L@D".H(S0$N``$@ k [QxMD MEDLINE Link]. J Interv Card Electrophysiol. Am J Med. 309(19):1166-8. [QxMD MEDLINE Link]. Ali A Sovari, MD, FACP, FACC is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Physician Scientists Association, American Physiological Society, Biophysical Society, Heart Rhythm Society, Society for Cardiovascular Magnetic ResonanceDisclosure: Nothing to disclose. Five Step Approach to Transcutaneous Pacing Step 1: Apply the pacing electrodes and consider sedation (eg. Ideal current is 1.25x what was required for capture. 7.1a) in order to minimize transthoracic impedance.If this configuration is unsuccessful or if electrodes are placed . Get new journal Tables of Contents sent right to your email inbox, Take the lead on safety with temporary cardiac pacing, Monitoring temporary pacemaker connections, Articles in PubMed by Karen Craig, RN, BS, Articles in Google Scholar by Karen Craig, RN, BS, Other articles in this journal by Karen Craig, RN, BS, Privacy Policy (Updated December 15, 2022). The patient eventually expires from multiple-system organ failure. Explain the purpose of TCP to your patient. Wolters Kluwer Health, Inc. and/or its subsidiaries. The most common indication for TCP is . Then calculate the NPV of these cash flows by dividing it by the discount rate. Complete AV block is generally the most important and clinically significant degree of block. If you do not have ventricular capture ensure the pacing box is turned on and that all connections are correct. Optimal placement for pads varies by manufacturer, but is generally anterior-posterior or anterior-lateral, with the former being most common. Video courtesy of Therese Canares, MD; Marleny Franco, MD; and Jonathan Valente, MD (Rhode Island Hospital, Brown University). Sinus node disease rarely requires temporary pacing. Resuscitation. You can see another example where an echo was used to verify capture here. You will also note that the underlying rhythm can be seen in the absolute refractory period of one of the (presumed to be) paced QRS complexes (red circle). 0 https://doi.org/10.1007/978-3-030-64661-5_18, Shipping restrictions may apply, check to see if you are impacted, Tax calculation will be finalised during checkout. External noninvasive temporary cardiac pacing: clinical trials. Trigano AJ, Azoulay A, Rochdi M, Campillo A. Electromagnetic interference of external pacemakers by walkie-talkies and digital cellular phones: experimental study. Use an instrument (SpO2, Doppler, capnography, or echo) to help confirm mechanical capture whenever possible. stream 60/min and milliamps to 0, Increase mA until electrical capture is obtained, Check to ensure the patient has mechanical capture ( Do not asses the carotid pulse for confirmation; electrical stimulation causes muscle jerking that may mimic the carotid pulse), Set the output 2 mA above the dose at which consistent mechanical capture is observed as a safety margin, reassess the patient to confirm if they are now hemodynamically stable ( increase rate as needed), reassess the patient to determine id sedation is now needed ( if not already administered), Advanced Airway - Endotracheal Intubation, Bio Chapter 20 pre lecture : Evolution of lif. Prehospital transcutaneous cardiac pacing for symptomatic bradycardia or bradyasystolic cardiac arrest: a systematic review. Part of Springer Nature. Pacing Clin Electrophysiol. Acad Emerg Med. This intervention can be used to over-ride a malignant tachydysrhythmia or compensate for symptomatic bradycardia. Jaworska K, Prochaczek F, Galecka J. Reuse of OpenAnesthesia content for commercial purposes of any kind is prohibited. This case will focus on the patient with a bradycardia and a heart rate less than 50/min. Simons GR. Correspondence to Answer: During transcutaneous pacing procedure, upon electrical and mechanical capture, it is recommended to increase the milliamps (mA) 10% higher than the threshold of initial electrical capture as a safety margin (usually 5-10 mA). Often 50-100 mA are required. Complications and outcomes of temporary transvenous pacing. fluids, atropine, digibind, glucagon, high dose insulin). This case was submitted by Roger Hancock with edits by Tom Bouthillet. x]$Gq\;gX0 {Yc|!$` optuuSY=wo*###;"?Y-W7~O>?O{/{zyj[ov~w{maot?)`]-7q7awk_-a5L@|yx\ s?9^kXuhs~8s\_}7C}q#N>:^?}8xa=\=sxbsx!_ ?baCzU>a~}es7o1M!4XFRn~>Rp"X Z'pqo !|)!Xry{(It_9T%v'8\AT$DN)s:i|hF}$M]GHW#0^,_2|X%#E3jn'cnC.yI'u?wB:,_pH,(5X8f# xOoxIY=dbm^DGOFwvNf Med Biol Eng Comput. Ho JD, Heegaard WG, Brunette DD. If either stroke volume or heart rate falls, there may be dire consequences in blood flow to the body, producing severe symptoms for the patient. A defibrillator with pacing capability. [21]. Effects of transcutaneous cardiac pacing on ventricular repolarization and comparison with transvenous pacing. The same goes for individual services or products. Ettin DCook T. Using ultrasound to determine external pacer capture. Usual practice is to have a pacing safety margin of at least 2 times (or 3 times if the patient has an unstable escape rhythm) - if the pacing threshold is 3, set at 7 (or 10). However, paramedics are still concerned about the patient's hypotension. [QxMD MEDLINE Link]. During TCP, pads are placed on the patients chest either in anterolateral position or anterior-posterior (AP) position. Although transcutaneous pacing has been used continuously for as long as 4-5 days, [22, 23] the sites at which the pads are applied should be changed every 4-5 hours to reduce skin burn and discomfort. Transcutaneous cardiac pacing may be associated with discomfort such as a burning sensation of the skin, skeletal muscle contractions, or both. Assess quality of femoral or radial pulses and monitor blood pressure. At ACLS Medical Training, we pride ourselves on the quality, research, and transparency we put into our content. Pacing Clin Electrophysiol. [QxMD MEDLINE Link]. Heart rate is determined by the bodys physical needs (via nervous system input) and is usually controlled by the sinus node. If cardiovascular symptoms are not caused by the bradycardia, the patient may not improve despite effective pacing. Third-degree burns associated with transcutaneous pacing. These heart contractions did not correspond with the surrounding thoracic muscle contractions generated by the pacer. If the positive electrode is placed anteriorly, the pacing threshold may increase significantly; this, in turn, increases the patients discomfort and may result in failure to capture. 19(2):134-6. hyperkalemia, drug overdose), Avoid placing the pads over an AICD or transdermal drug patches, There is little data on optimal placement however, try to place the pads as close as possible to the PMI (point of maximal impulse) [1,2]. overdrive pacing for refractory tachyarrhythmias after failure of electrical cardioversion and drug therapy. Assessment of capture (typically between 50-90 mA): look at the ECG tracing on the monitor for pacer spikes that are each followed by a QRS complex. Richard A Lange, MD, MBA is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, American Heart Association, Association of Subspecialty ProfessorsDisclosure: Nothing to disclose. Overbay D, Criddle L. Mastering temporary invasive cardiac pacing. Insert the transcutaneous pacing wire. . to perform CPR) during pacing. The electrocardiogram of ventricular capture during transcutaneous cardiac pacing. The literature reports a wide range of sedation techniques and sedative agents. Many medical comorbidities and medications may affect the hearts conduction system and cause significant changes in heart rate and thus cardiac output. Transcutaneous temporary pacing is mostly used as a "bridging" modality in emergency circumstances. [1], Shortly after cardiac pacing was initiated, the patients systolic blood pressure dropped to 50 mmHg. Safety and efficacy of noninvasive cardiac pacing. 2023 Springer Nature Switzerland AG. With false capture, you will generally see a near-vertical upstroke or down-stroke to the phantom QRS complex (which is actually electrical artifact created by the current passing between the pacing pads). Transcutaneous pacing with external pacemakers is indicated as a temporizing measure for treatment of symptomatic bradycardias, including sinus bradycardias and atrioventricular (AV) nodal blocks; it may also be used prophylactically in patients with these rhythms who are maintaining a stable blood pressure. Epstein AE, DiMarco JP, Ellenbogan KA, et al. A preliminary report. Nursing2006: April 2006 - Volume 36 - Issue - p 22-23. . You are being redirected to Conscious patients require analgesia for discomfort unless delay for sedation will cause/contribute to deterioration. Pacing spikes are visible with what appear to be large, corresponding QRS complexes. The wire is secured with a loop of redundancy to the skin with sutures and occlusive bandage placed. HV[O0~cwB61i])I\u;N6v#TUssTlBj5X\y|BW-f%a{|@Gc"HQahxZt;cFb)Qk$B)mA:'h}Lq, `'Q #564!R.M!CHR`!m:nj+\Pl,V|im}NBH'!9 3I6@* KpW2CU(%ph)m0fEYjbBO45P;pH+!KLT[Vv,D]'tl!gdVK\Y{}X METHOD OF INSERTION AND/OR USE place pads in AP position (black on anterior chest, red on posterior chest) connect ECG leads set pacemaker to demand turn pacing rate to > 30bpm above patients intrinsic rhythm set mA to 70 start pacing and increase mA until pacing rate captured on monitor 50(9):877-83. Pacing Clin Electrophysiol. Ramin Assadi, MD is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Medical Association, Society for Cardiovascular Angiography and InterventionsDisclosure: Nothing to disclose. N Engl J Med. 2. Know when to call for expert consultation about complicated rhythm interpretation, drugs, or management decisions. 2004;24(3):2532. Chest pressure can be applied and cardiopulmonary resuscitation performed by pressing on the pads. The patient appeared to have palpable pulses; however, the rhythm contractions of the patients body from the pacer shocks made this assessment difficult. Please try again soon. Holger JS, Minnigan HJ, Lamon RP, Gornick CC. 2008;117:282040. Google Scholar. Technique: Perform Transcutaneous Pacing are as follows: Step 1: Place pacing electrodes on the chest Step 2: Turn the Pacer on. Medscape Education. 2018:bcr-2018-226769. [QxMD MEDLINE Link]. Pecha S, Aydin MA, Yildirim Y, et al. 5th ed. Minneapolis; Medtronic; c. 2019. Questions or feedback? 2007. :Use of ultrasound to determine ventricular capture in transcutaneous pacing. Krista J. Allshouse . B, No skeletal muscle contraction/movement occurred while pacing with the extracardiac lead at 2.7 V. This is supported by the unchanging accelerometer signals before and after pacing is delivered. Craig, Karen RN, BS. Local: 613-737-7228 | Long Distance: 877-587-7736, Ottawa, 2475 Don Reid Drive, Ottawa, On,K1H 1E2Kingston, 400-1471 John Counter Blvd, Kingston, ON, K7M 8S8, 400-1471 John Counter Blvd, Kingston, ON, K7M 8S8, Increasing mA beyond initial electrical capture threshold, Ottawa, 2475 Don Reid Drive, Ottawa, On,K1H 1E2, Kingston, 400-1471 John Counter Blvd, Kingston, ON, K7M 8S8, Continuing Education and Certification Team, Return to Clinical Practice (Service Form). % [QxMD MEDLINE Link]. A symptomatic bradycardia exists when 3 criteria are present: You must perform a focused history and physical examination to identify the signs and symptoms of a bradycardia. Holger J S, Lamon R P, and Minnigan H J et al. Note that pacing temporary wires at unnecessarily high outputs may lead to premature carbonisation of the leads and degradation of wire function. Assess his hemodynamic response to pacing by assessing his central pulses (see Cautions for using TCP) and taking blood pressure (BP) on both arms. Philadelphia: Elsevier; 2019. p. 5071. Perform, but do not rely on a pulse check! [PMID:10595889], 4. 1983 Nov 10. Transcutaneous Cardiac Pacing. The pacing electrode pads of an external pacing unit and locations in which each pad should be placed. Springer, Cham. In contrast, true electrical capture will show wide QRS complexes with tall, broad T-waves. 309(19):1166-8. This will pause the TCP spikes for a few seconds so you can identify the underlying rhythm. 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. [QxMD MEDLINE Link]. 2002;25(2):2604. OpenAnesthesia content is intended for educational purposes only. Philadelphia: Elsevier; 2019. p. 45660. 124 0 obj <> endobj We guarantee the ACLS Medical Training provider card will be accepted worldwide and offer a 100% money back guarantee. Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. hemodynamically unstable bradycardias that are unresponsive to atropine, bradycardia with symptomatic escape rhythms that don't respond to medication, cardiac arrest with profound bradycardia (if used early), pulseless electrical activity due to drug overdose, acidosis, or electrolyte abnormalities. encoded search term (Transcutaneous Cardiac Pacing) and Transcutaneous Cardiac Pacing, Malignant Arrhythmia and Cardiac Arrest in the Operating Room, Arrhythmogenic Right Ventricular Dysplasia (ARVD), Atrioventricular Nodal Reentry Tachycardia, New Tx Approach for Immunotherapy-Induced Myocarditis, Silent Bradycardia Common on Loop Recorders, No Pacemaker Needed, Wearable Fitness Trackers May Interfere With Cardiac Devices, The '10 Commandments' for the 2022 ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. If the patient has adequate perfusion, observe and monitor (Step 4 above), If the patient has poor perfusion, proceed to Step 5 (above), Atropine 0.5 mg IV to a total dose of 3 mg. [You can repeat the dose every 3 to 5 minutes up to the 3 mg maximum], Dopamine 2 to 20 mcg/kg per minute (chronotropic or heart rate dose), Hemodynamically unstable bradycardia (eg, hypotension, acutely altered mental status, signs of shock, ischemic chest discomfort, acute heart failure [AHF] hypotension), Unstable clinical condition likely due to the bradycardia. Webster J G, and Tompkins W J et al. Your message has been successfully sent to your colleague. [QxMD MEDLINE Link]. your express consent. It is important to be able to recognize the various rhythms associated with inadequate heart rates and understand when support may be needed. Capture was achieved at 110 mA (ems12lead.com). [QxMD MEDLINE Link]. PKQb< k(E=$@[iAK2)^a0}u&+IDWdbI&r All material on this website is protected by copyright, Copyright 1994-2023 by WebMD LLC. Europace 2013; 15:1287. Step 3: Set the demand rate to approximately 60/min. Content posted on this site is NOT medical advice and should not be used to treat patients or yourself. Cardiac Pacing and Resynchronization Clinical Practice Guidelines (ESC/EHRA, 2021), https://www.medscape.com/viewarticle/957561, Society for Cardiovascular Magnetic Resonance, Central Society for Clinical and Translational Research, Society for Cardiovascular Angiography and Interventions. Skeletal muscle contraction occurs at current levels as low as 10 milliamps, and does NOT suggest electrical or mechanical capture. Transcutaneous Pacing (TCP) is a temporary means of pacing a patient's heart during an emergency and stabilizing the patient until a more permanent means of pacing is achieved. Key to the case management is the determination that the symptoms or signs due to the decreased heart rate. [cited 2019 July 22]. The patient begins to move and reaches for the pacing pads. The cornerstones of managing bradycardia are to: In addition, you must know the techniques and cautions for using TCP. Zagkli F, Georgakopoulou A, Chiladakis J. Snoring respirations are noted and a slow carotid pulse is present. The opinions expressed on the website are the opinions of the website and content authors alone and do not represent the policies or opinions of Maine Medical Center, Maine Medical Partners,MaineHealth, or Tufts University School of Medicine. 2018 Aug. 36(8):1523.e5-.e6. Zagkli F, Georgakopoulou A, Chiladakis J. Your 10% OFF discount codehas been sent to your email. Pacing Clin Electrophysiol. However, paramedics are still concerned about the patients hypotension. Equipment used in transcutaneous cardiac pacing includes the following: Although some pacing units provide only pacing, most defibrillators provide both cardiac pacing and rhythm monitoring. 1988 Mar. The size of the electrode pads usually ranges from 8-15 cm, and the pacing electrodes can be applied by medical personnel. Am J Emerg Med. Medication Summary The goal of pharmacotherapy is to provide sedation and pain medication to relieve the discomfort, such as burning sensation of the skin and/or skeletal muscle contractions that. Once the TPW has been positioned check stability by asking the patient to take deep Project the cash flows ten years into the future, and repeat steps one and two for all those years. Ag[DrXk u"s[Eb|}pxJtKD& "qJ=n cWy{Xt_,?%^,coS|v\pgXxOu;3.bi|JiF3I1P#I]J5oarW6{#%E.&U"y ; \ LWQ["F11bOE0XnCfl[o`bz+~.XZUX{`JR3`r=. Sedation for electrophysiological procedures. 2018 Jun. Next, perform the Primary Assessment, including the following: Decision Point: Adequate Perfusion? In: Brown DL, editor. IO access is obtained in right proximal tibia. A discussion of transcutaneous pacing and indications for the prophylactic placement of a transvenous pacemaker has been included. For more information, please refer to our Privacy Policy. Advance the pacing wire through the cannula and into the ventricle. https://profreg.medscape.com/px/getpracticeprofile.do?method=getProfessionalProfile&urlCache=aHR0cHM6Ly9lbWVkaWNpbmUubWVkc2NhcGUuY29tL2FydGljbGUvOTg5MzktcGVyaXByb2NlZHVyZQ==. Acute myocardial infarction complicated by ventricular standstill terminated by thrombolysis and transcutaneous pacing. Advance the plastic sheath over the pacing wire until it straightens out and covers the J-shaped end of the pacing wire. When considering institution of transcutaneous pacing, always think about alternate causes for acute dysrhythmia, e.g. 148 0 obj <>/Filter/FlateDecode/ID[<080B985F646C544C9743A9819668209B>]/Index[124 45]/Info 123 0 R/Length 115/Prev 507343/Root 125 0 R/Size 169/Type/XRef/W[1 3 1]>>stream Technique: Ideal pacer pad placement sandwiches the heart between the pacing pads and mimics the hearts normal electrical axis. Step 1: Place pacing electrodes on the chest. Note that pacing temporary wires at unnecessarily high outputs may lead to premature carbonisation of the leads and degradation of wire function. Algorithms for loss of capture for transcutaneous and transvenous pacemakers have been developed. The problem of false capture (also known as echo distortion) is under-recognized and under-reported in the medical literature. The. In this chapter we discuss the implications of a slow heart rate and the treatment options available including how to place these temporary pacing devices and trouble-shooting to achieve the best clinical outcome. Do not assess the carotid pulse to confirm mechanical capture; eletrical stiulation causes muscular jerking that may mimic the carotid pulse. [QxMD MEDLINE Link]. to maintaining your privacy and will not share your personal information without Document your patient's initial cardiac rhythm (including rhythm strip and 12-lead ECG if possible), the signs and symptoms that indicated his need for pacing therapy, the pacer settings (rate, current output, pacing mode), a cardiac rhythm strip showing electrical capture, the patient's pulse and BP, his pain intensity rating, analgesia or sedation provided, and his response. Rosenthal E, Thomas N, Quinn E, Chamberlain D, Vincent R. Transcutaneous pacing for cardiac emergencies. and Thomas Cook, M.D. [QxMD MEDLINE Link]. First human demonstration of cardiac stimulation with transcutaneous ultrasound energy delivery: implications for wireless pacing with implantable devices. With the etiology of the patients hypotension unclear, the decision was made to use transthoracic ultrasonography to assess the adequacy of her ventricular contractions., Initially, the ultrasound demonstrated ventricular contractions at a rate of 30-40 beats per minute. If capture occurs, slowly decrease output until capture is lost (threshold) then add 2 mA or 10% more than the threshold as a safety margin. Appropriately used, external cardiac pacing is associated with few complications. 7 Steps to Calculate the Magin of Safety. Circulation - Pacing (transcutaneous) This procedure is performed using procedural sedation which is covered separately Indications Bradycardia (HR <40bpm) and Unstable (altered mental status, SBP <90mmHg, angina, pulmonary oedema) and Unresponsive or unsuitable for medical therapy Contraindications (absolute in bold) The posterior electrode, which should be of positive polarity, should be placed inferior to the scapula or between the right or left scapula and the spine; it should not be placed over the scapula or the spine. D Conduct a problem-focused history and physical examination; search for and treat possible contributing factors. During transcutaneous pacing procedure, upon electrical and mechanical capture, it is recommended to increase the milliamps (mA) 10% higher than the threshold of initial electrical capture as a safety margin (usually 5-10 mA).