Dr Alan Begg Summarises Recommendations in SIGN’s Latest Guidance on Cardiac Arrhythmias That are Relevant to Primary Care and Highlights some Major Advances in Treatment
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Find key points and implementation actions for STPs and ICSs at the end of this article
Coronary heart disease (CHD) is associated with many cardiac arrhythmias, which are especially common during acute coronary syndrome (ACS). Ventricular tachyarrhythmias are an important cause of cardiac arrest and sudden cardiac death, and people with left ventricular dysfunction and heart failure are similarly at risk. A growing number of people with CHD are also affected by atrial fibrillation (AF), which is associated with an increased risk of stroke.1
In September 2018, SIGN published an updated guideline (SIGN 152) on Cardiac arrhythmias in coronary heart disease,1 the previous version of the same guideline having been published in February 2007.2
Please note that not all of the treatments discussed in this article currently (January 2019) have UK marketing authorisation for the indications mentioned. The prescriber should follow relevant professional guidance, taking full responsibility for all clinical decisions. Informed consent should be obtained and documented. See the General Medical Council’s guidance on Good practice in prescribing and managing medicines and devices3 for further information.
The Need for an Updated Guideline
Since the publication of SIGN’s previous guideline, there have been major advances in catheter ablation and device-based therapies for arrhythmias. There have also been changes in pharmacological and other interventional therapy related to CHD, which are also reflected in the new guidance.
The guideline excludes arrhythmias not associated with CHD, such as supra-ventricular tachycardias and those associated with both inherited ion channel disorders, such as long QT syndrome, and non-ischaemic cardiomyopathies. It does, however, outline the rhythm management of AF.
Much of the management of CHD arrhythmias occurs in secondary care but this article will concentrate on the recommendations that are relevant to and important for primary care.
Arrhythmias Associated with Cardiac Arrest
Sudden Cardiac Death
Coronary heart disease is the cause of sudden cardiac death (SCD) in 70% of cases although SCD can occur as a primary event without the recognition of pre-existing CHD.1 Asymptomatic individuals with multiple risk factors for CHD (e.g. diabetes mellitus, hypertension and left ventricular hypertrophy, hyperlipidaemia, dietary factors, excessive alcohol consumption, physical inactivity, and smoking) are at increased risk for primary SCD so SIGN recommends risk-factor intervention in these individuals, including prescribing lipid-lowering and antihypertensive drugs.1
Health promotion measures within the general population are important and we should all be encouraged to take moderate intensity physical activity to help prevent SCD.1,4
Out-of-hospital Cardiac Arrest
Bystander Cardiopulmonary Resuscitation
Bystander cardiopulmonary resuscitation (CPR) is associated with increased survival in out-of-hospital cardiac arrest.1 For this reason, the number of people being trained in CPR should be increased, including laypeople who have a high probability of witnessing a cardiac arrest.1 CPR should be taught as part of the school curriculum to promote the knowledge and retention of resuscitation skills. SIGN 152 also recommends that healthcare workers with direct patient contact should have an annual refresher course in CPR.1
Defibrillation is the definitive intervention in ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT).1 The shorter the delay in delivering the first shock, the better the patient’s likelihood of surviving to hospital discharge, so the first shock should be administered without delay for witnessed cardiac arrests and after 2 minutes of CPR in unwitnessed cardiac arrests.1
Automated external defibrillators (AEDs), which guide first responders as to when and how to deliver a shock, are increasingly the type most likely to be available in primary care.
In line with the SIGN guidance, two AEDs are positioned in the author’s health centre at either end of the central atrium (Figure 1), with a third located outside the building and registered with the Scottish Ambulance Service.
This provision facilitates:
- prompt defibrillation in a healthcare facility, in a location with a high probability of a cardiac arrest
- all healthcare workers being trained, authorised, and encouraged to perform defibrillation
- AEDs available for all first responders
- the use of AEDs integrated with the emergency services.
It is worth highlighting that in SIGN 152 there was no evidence on the clinical or cost effectiveness of AEDs in rural areas.1 Home provision of an AED did not improve survival following cardiac arrest when added to CPR training for relatives of patients with a previous myocardial infarction who had a low risk of SCD.1
CPR and defibrillation should be performed and administered in accordance with the Resuscitation Council (UK) guidelines.1,5
Recommendations for the use of therapeutic adjunctive therapies for those undertaking pre-hospital advanced resuscitation are highlighted in Box 1.
|Box 1: Adjunctive Therapies in Peri-arrest Period1|
Intravenous adrenaline/epinephrine should be used if there is:
VF=ventricular fibrillation; VT=ventricular tachycardia; Scottish Intercollegiate Guidelines Network. Cardiac arrhythmias in coronary heart disease. SIGN 152. Edinburgh: SIGN, 2018. Available at: www.sign.ac.uk/our-guidelines/cardiac-arrhythmias-in-coronary-heart-disease
Arrhythmias Associated with Acute Coronary Syndrome
The recommendations in this section of the guideline tend to relate mainly to the secondary care setting and are unlikely to be of direct relevance to care in the community.
The following may be of interest to the general practitioner:1
- class 1c antiarrhythmic drugs are not used to treat AF in patients who have acute coronary syndrome (ACS)
- permanent pacing is indicated if there is persistent (more than 7 days post myocardial infarction [MI]) Mobitz type II second- or third-degree block
- people who have VF or haemodynamically significant VT more than 48 hours after an infarction should be considered for an implantable cardioverter defibrillator (ICD)
- routine use of antiarrhythmic drugs is not recommended following ACS
- omega-3 fatty acid supplements should not be offered for the reduction of CVD risk
- eplerenone will significantly reduce the mortality risk and the risk of sudden death in specific circumstances defined in the guidance.
The risk of sudden death is greatest in the 30 days following ACS and declines over the next 2 years. This risk is associated with left ventricular (LV) dysfunction but can also occur if there is preserved LV function. For this reason, all patients with ST-elevation ACS should undergo assessment of LV function for risk stratification at least 6 weeks following an acute event.
Arrhythmias Associated with Chronic Coronary Heart Disease/Left Ventricular Dysfunction
Atrial fibrillation (AF) is a common complication of ischaemic heart disease, although the evidence base for its management in this group of patients is complicated by the inclusion of other patients with specific disease processes.1
Rate control is the recommended strategy for the management of patients with well-tolerated AF.1 An initial target of less than 110 bpm should be aimed for using beta blockers, rate-limiting calcium channel blockers, or digoxin. A combination may be required but as digoxin does not control the heart rate effectively during exercise, digoxin should only be used as a first-line therapy in people who are sedentary or who have overt heart failure.
Patients who remain severely symptomatic despite adequate rate control should be considered for rhythm control.1 Amiodarone or sotalol are effective in preventing AF recurrence and are the treatments that should be considered, if required, where symptoms remain troublesome.1
The CASTLE-AF trial, which compared catheter ablation to medical therapy (rate or rhythm control), revealed a benefit for ablation therapy in those with LV ejection fraction in the range 25–35%.6 Refer for consideration of ablation those patients remaining symptomatic:
- despite rate control
- with an intolerance to rate-control medication
- with a resistance to one or more antiarrhythmic drugs
- who have LV systolic dysfunction with an ejection fraction of 25–35%.
In recent years, primary care teams have been extremely effective in identifying patients in the community with permanent or persistent AF. There has been a significant change in the use of effective antithrombotic prophylaxis for stroke prevention with increasing prescription of direct oral anticoagulants. The use of antithrombotic therapy in this situation is covered in SIGN 129.7
Implantable Cardioverter Defibrillator Therapy
Patients who survive VF or sustained symptomatic VT due to a previous MI have improved survival following implantable cardioverter defibrillator (ICD) implantation compared with amiodarone therapy.1 Those with a LV ejection fraction (LVEF) of 35% or less derive more benefit from an ICD compared with those with preserved LV function.1
The recommendations in the guideline are that, in the absence of acute ischaemia or treatable cause, patients who survive the following ventricular arrhythmias should be considered for ICD implantation:1
- cardiac arrest VT or VF
- VT with syncope or haemodynamic compromise
- VT without syncope if LVEF ≤35%.
Psychological or emotional factors can influence and confound the incidence of cardiac arrhythmia1 so it is important that these factors are considered.
It is recommended that patients with chronic arrhythmias and cardiac arrest should be screened for anxiety or depressive disorders, with referral to specialist psychology services where appropriate.1 Similarly, selective cognitive screening should be available after a cardiac arrest and for older patients with cardiac disease who experience memory or other cognitive difficulties.
Interestingly, psychosocial adjustment problems are more common in ICD recipients younger than 50 years. A meta-analysis, however, found no difference in psychosocial outcome between patients with ventricular arrhythmias treated with ICDs and those treated with medical therapy, or between patients before and after ICD implantation.1,8 The implication is that poor psychosocial outcome in ICD recipients may be associated with the underlying cardiac condition rather than a direct response to implantation of the ICD device and its therapy.
Psychological interventions with a cognitive behavioural component are an important part of a cardiac rehabilitation programme.
Chapters 8 and 9 in SIGN 152 cover relevant sources of information and implementation. One of the sources mentioned is the charity Chest Heart & Stroke Scotland, who have produced a module Out of hospital cardiac arrest (OHCA) as part of their HEARTe online training programme.9 This module, which is freely available on the web, provides support and guidance for those attending an OHCA in a trained capacity and is an important resource in helping to implement this SIGN guideline. Primary care teams have an important role in the understanding and early detection of cardiac arrhythmias. It is important that all members of the team have the skills appropriate to their role, along with all the necessary equipment to ensure implementation of this guideline, in order to improve clinical outcomes.
Dr Alan Begg
GP, Montrose; GPwSI in cardiovascular disease; member of the Familial Arrhythmia Network Scotland (FANS) steering group and a Director of Chest Heart and Stroke Scotland.
CPR=cardiopulmonary resuscitation; ACS=acute coronary syndrome; LV=left ventricular; AF=atrial fibrillation; ICD=implantable cardioverter defibrillator
|Implementation Actions for STPs and ICSs|
Written by Dr David Jenner, GP, Cullompton, Devon
The following implementation actions are designed to support STPs and ICSs with the challenges involved with implementing new guidance at a system level. Our aim is to help you consider how to deliver improvements to healthcare within the available resources.
STP=sustainability and transformation partnership; ICS=integrated care system; SIGN=Scottish Intercollegiate Guidelines Network; AEDs=automated external defibrillators; ICDs=implantable cardioverter defibrillators