European Resuscitation Council Guidelines for Resuscitation ... - CPR

• If the arrhythmia persists and is not atrial flutter, use adenosine.Give 6 mg as a rapid intravenous bolus. Record an ECG(preferably multi-lead) during each injection. If the ventricularrate slows transiently but the arrhythmia then persists, look foratrial activity such as atrial flutter or other atrial tachycardia andtreat accordingly. If there is no response to adenosine 6 mg, givea 12 mg bolus; if there is no response, give one further 12 mgbolus.This strategy will terminate 90–95% of supraventriculararrhythmias. 610• Successful termination of a tachyarrhythmia by vagal manoeuvresor adenosine indicates that it was almost certainly AVNRTor AVRT. Monitor the patients for further rhythm abnormalities.Treat recurrence either with further adenosine or with alonger-acting drug with AV nodal-blocking action (e.g., diltiazemor verapamil).• If adenosine is contraindicated or fails to terminate aregular narrow-complex tachycardia without demonstratingthat it is atrial flutter, give a calcium channel blocker(e.g., verapamil or diltiazem).Irregular narrow-complex tachycardiaAn irregular narrow-complex tachycardia is most likely to be AFwith an uncontrolled ventricular response or, less commonly, atrialflutter with variable AV block. Record a 12-lead ECG to identifythe rhythm. If the patient is unstable with adverse features causedby the arrhythmia, attempt synchronised electrical cardioversionas described above. The European Society of Cardiology providesdetailed guidelines on the management of AF. 611If there are no adverse features, treatment options include:• rate control by drug therapy;• rhythm control using drugs to encourage chemical cardioversion;• rhythm control by electrical cardioversion;• treatment to prevent complications (e.g., anticoagulation).Obtain expert help to determine the most appropriate treatmentfor the individual patient. The longer a patient remains in AF, thegreater is the likelihood of atrial clot developing. In general, patientswho have been in AF for more than 48 h should not be treated bycardioversion (electrical or chemical) until they have received fullanticoagulation or absence of atrial clot has been shown by transoesophagealechocardiography. If the clinical scenario dictates thatcardioversion is required and the duration of AF is greater than48 h (or the duration is unknown) give an initial intravenous bolusinjection of heparin followed by a continuous infusion to maintainthe activated partial thromboplastin time at 1.5–2 times the referencecontrol value. Anticoagulation should be continued for at least4 weeks thereafter. 611If the aim is to control heart rate, the drugs of choice are betablockers612,613 and diltiazem. 614,615 Digoxin and amiodarone maybe used in patients with heart failure. Magnesium has also beenused although the data supporting this is more limited. 616,617If the duration of AF is less than 48 h and rhythm control isconsidered appropriate, chemical cardioversion may be attempted.Seek expert help and consider ibutilide, flecainide or dofetilide.Amiodarone (300 mg intravenously over 20–60 min followed by900 mg over 24 h) may also be used but is less effective. Electricalcardioversion remains an option in this setting and willrestore sinus rhythm in more patients than chemical cardioversion.Seek expert help if any patient with AF is known or found to haveventricular pre-excitation (WPW syndrome). Avoid using adenosine,diltiazem, verapamil or digoxin in patients with pre-excitedAF or atrial flutter, as these drugs block the AV node and cause arelative increase in pre-excitation.18 de 0ctubre de 2010 www.elsuapdetodos.comC.D. Deakin et al. / Resuscitation 81 (2010) 1305–1352 1331BradycardiaA bradycardia is defined as a heart rate of 0.20 s), and is usually benign. SeconddegreeAV block is divided into Mobitz types I and II. In Mobitztype I, the block is at the AV node, is often transient and may beasymptomatic. In Mobitz type II, the block is most often below theAV node at the bundle of His or at the bundle branches, and is oftensymptomatic, with the potential to progress to complete AV block.Third-degree heart block is defined by AV dissociation, which maybe permanent or transient, depending on the underlying cause.Initial assessmentAssess the patient with bradycardia using the ABCDE approach.Consider the potential cause of the bradycardia and look for theadverse signs. Treat any reversible causes of bradycardia identifiedin the initial assessment. If adverse signs are present start to treatthe bradycardia. Initial treatments are pharmacological, with pacingbeing reserved for patients unresponsive to pharmacologicaltreatments or with risks factors for asystole (Fig. 4.12).Pharmacological treatmentIf adverse signs are present, give atropine, 500 g, intravenouslyand, if necessary, repeat every 3–5 min to a total of 3 mg. Dosesof atropine of less than 500 g, paradoxically, may cause furtherslowing of the heart rate. 618 In healthy volunteers a dose of3 mg produces the maximum achievable increase in resting heartrate. 619 Use atropine cautiously in the presence of acute coronaryischaemia or myocardial infarction; increased heart rate mayworsen ischaemia or increase the zone of infarctionIf treatment with atropine is ineffective, consider secondline drugs. These include isoprenaline (5 gmin −1 starting dose),adrenaline (2–10 gmin −1 ) and dopamine (2–10 gkg −1 min −1 ).Theophylline (100–200 mg slow intravenous injection) should beconsidered if the bradycardia is caused by inferior myocardialinfarction, cardiac transplant or spinal cord injury. Consider givingintravenous glucagon if beta-blockers or calcium channel blockersare a potential cause of the bradycardia. Do not give atropine topatients with cardiac transplants—it can cause a high-degree AVblock or even sinus arrest. 620www.elsuapdetodos.comPacingInitiate transcutaneous pacing immediately if there is noresponse to atropine, or if atropine is unlikely to be effective.Transcutaneous pacing can be painful and may fail to produceeffective mechanical capture. Verify mechanical capture andreassess the patient’s condition. Use analgesia and sedation to controlpain, and attempt to identify the cause of the bradyarrhythmia.If atropine is ineffective and transcutaneous pacing is not immediatelyavailable, fist pacing can be attempted while waiting for