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Top tips on implantable cardiac devices

League tables suggest the UK could make more use of heart rhythm devices. Cardiologists Dr Richard Charles and Dr Chris Plummer offer hints on spotting who could benefit and on the care of people who already have one

League tables suggest the UK could make more use of heart rhythm devices. Cardiologists Dr Richard Charles and Dr Chris Plummer offer hints on spotting who could benefit and on the care of people who already have one

1. Cardiac device provision in the UK is insufficient and inequitable – check if levels in your area are lower than average.

Over 41,000 heart rhythm devices – pacemakers (PM) for bradycardia, implantable cardioverter defibrillators (ICD) for life-threatening ventricular arrhythmias and cardiac resynchronisation systems (CRT) for severe refractory heart failure are implanted every year in the UK, so every GP will see one or more new device patients each year.

But the UK languishes towards the bottom of the international league table for the implantation of all three device classes, despite evidence that we have the same clinical need as countries with higher rates.

Despite correction for major clinical and population variables, there is strong evidence of striking regional inequity of device provision in the UK, down to Cardiac Network and PCT level.

GPs are most important in identifying these patients and must have a high index of suspicion, especially in the elderly and those with heart failure.

2. Pacemakers are the only safe treatment for symptomatic and prognostically significant bradycardias.

An incontestable evidence base affirms the safety and efficacy of pacemakers for bradycardia.

The great majority are implanted for sinus node disease or atrioventricular block, which are predominantly diseases of the elderly – 75% are implanted in patients over 75 years of age.

Pacemakers are highly cost-effective in appropriately indicated patients, comparing favourably with many common treatments in heart disease.

3. Simple investigations and referral to your cardiologist should be encouraged. Have a low threshold of suspicion that a PM might be needed – especially in older people.

The symptoms of bradycardia can be very non-specific: syncope is important, but ‘funny turns', lethargy and effort intolerance are also common. Many patients with nebulous diagnoses of ‘epilepsy' have been found instead to need a PM.

Always record an ECG and use a direct access service for a 24-hour ECG recording where available. Always refer in cases of doubt – the cardiologist can apply the required specificity.

Remember that many PM patients are currently being missed in the UK. (Detailed indications for device therapy are available from the USA1 and Europe2).

4. Know your patient's ejection fraction (EF) after a heart attack or in heart failure.

ICDs are of proven efficacy and cost-effectiveness in saving the lives of high-risk patients with coronary heart disease and cardiomyopathies (primary prevention) and in those who have survived a cardiac arrest3.

Many of these patients will be identified by finding a low left ventricular EF (35% or less), usually by echocardiography, which should be routinely measured after MI and in heart failure (HF) patients. Refractory HF patients with a low EF and broad QRS complexes – usually left bundle branch block – on an ECG may derive major symptomatic and survival benefits from CRT implantation.

5. Explain to patients when they can safely drive after device implantation.

Patients may not drive for one week after PM implantation or revision, for one month after ICD implantation for primary prevention or six months after ICD implantation for secondary prevention. Special provisions apply for large goods vehicle (LGV) and passenger carrying vehicle (PCV) licence holders. Details are available from the DVLA4.

6. Patients often want to know what electrical equipment is safe and what may pose a hazard. Domestic appliances, including microwave ovens, should not cause any concern at all.

Patients may safely pass through security barriers. Mobile phones may be used; it is advised to keep the phone more than six inches away from the device – use the opposite ear. Electrocautery may be used for surgery with precautions that are available from the MHRA5.

An ICD shock does not pose a danger to other people touching or holding the patient at the time of a shock delivery.

7. There are very few ‘do nots' for device patients. MRI scanners may be hazardous to pacemakers and patients; risks and benefits require individual specialist discussion.

Powerful magnetic fields from arc welders and industrial equipment may inhibit PM functions. Radiation therapy for cancers may damage circuitry, and the device needs careful shielding. Shock wave lithotripsy for renal stones can damage PMs, especially if they are sited in the abdomen rather than the chest.

Device patients do not need antibiotic prophylaxis against infective endocarditis unless there is a separate indicated condition6.

8. Patients must have regular follow-up at a dedicated clinic.

All cardiac devices are complex, sophisticated, and require regular follow-up, whether or not the patient has been symptomatic. Device clinics monitor battery performance to identify the need for replacement, interrogate the device for a wide range of diagnostic information, and reprogram the device to optimise performance.

Remote monitoring of devices, allowing transmission of data to the implanting centre via a modem link, will imminently become more widely available across the UK, saving many hospital visits.

9. Infection associated with an implanted device is always serious and potentially lethal. It may appear in the post-operative or post-discharge phase, or at any time remote to the implant.

Take seriously any complaint of new or chronic pain at the implant site. Refer urgently if the site shows signs of reddening, skin thinning or the device is adhering to the tissues – it should be mobile under the skin. These can be signs of infection or pre-erosion.

An ICD shock requires the device to be interrogated. Any recurrence of symptoms for which the device was originally implanted requires clinic evaluation.

10. When patients are dead or dying PMs do not need to be reprogrammed but must be removed before cremation to prevent explosion.

ICDs should be reprogrammed to switch off shocks prior to expected death – in an emergency a ring magnet (available in coronary care units and device clinics) will temporarily achieve this.

ICDs, including CRT with a shock function, must be reprogrammed (shocks switched off) before removal for cremation to avoid giving shocks to the remover. Your local implanting centre will be able to advise.

Dr Richard Charles is emeritus consultant cardiologist at The Cardiothoracic Centre, Liverpool

Competing interests None declared

Dr Chris Plummer is consultant cardiologist at Freeman Hospital, Newcastle upon Tyne

Competing interests None declared

The website www.devicesurvey.com provides National Survey Reports for 2003/4 and for 2006. Additionally, all Cardiac Networks have been encouraged by the Network Devices Survey Group, and by the Department of Health to commission detailed reports that provide analysis of device utilisation, corrected for the age and sex of the local population, down to PCT level. This allows valid direct comparison between Cardiac Network areas and PCTs across the country.

Patient resource

Arrhythmia Alliance

Heart pacemaker

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