Why You Should Use ECG Event Recorders in Primary Care.

The updated NICE clinical guideline CG180 (2014) was published in June 2014. It gives guidance on the management of atrial fibrillation and recommends an ECG should be performed on all patients where atrial fibrillation is suspected where an irregular pulse has been detected, whether symptomatic or not.

It recommends using ambulatory ECG recording in patients with suspected paroxysmal AF as follows:

  • A 24-hour Holter ECG monitor should be used in those with suspected asymptomatic episodes or symptomatic episodes less than 24 hours apart.
  • An event recorder ECG should be used in those with symptomatic episodes more than 24 hours apart.

The National Service Framework for Coronary Heart Disease chapter on cardiac arrhythmias lists three quality requirements relating to patient support, diagnosis and treatment and sudden cardiac death.

So why aren’t more GPs using Event Recorders in Primary Care?

There are two main types of ECG recorders worn by patients in an ambulatory setting away from the

Surgery. They are Holter ECG recorders like the Meditech CardioMera or Event Capture ECG recorders like the Meditech CardioBlue and DCBiomed InstantCheck.

They are generally used to investigate suspected symptoms of arrhythmia including palpitations, light-headedness or syncope (partial or complete loss of consciousness), which have not been detected during a shorter 12 lead, surgery based ECG.

Holter or event recorder

Continuous full disclosure Holter ECG monitors were first used in the 1970s and typically operate for 24-48 hours recording every single heartbeat during this period.

This can mean that upwards of 100,000 beats are recorded over a 24 hour period. They are especially useful if the wearer does not feel or is not aware of the ECG abnormality, and are typically more expensive than event recorders.

In most cases data is now stored digitally either on internal flash memory or on removable SD data cards.

Data is uploaded to a computer where software automatically analyses the recording classifying it by beat type, identifying and labelling specific arrhythmias and in some cases, providing a textual summary for the clinician.

Reports should be customisable and have the ability to be attached to the patient’s clinical notes electronically.

Most Holter analysis software can run on a desktop PC and a separate dedicated PC is not required. This makes the analysis of the recording much quicker.

Event ECG recorders are different and are designed for patients who experience symptoms very infrequently and require monitoring over several days or even weeks.

This type of recorder is usually patient activated by pushing a button, but some can be programmed to record automatically at pre-set intervals or will trigger automatically at the onset of certain arrhythmias.

Some event recorders record post event data only. Others operate in a ‘loop’ memory mode so the device records 30 seconds of pre event and 30 seconds post event data. This is useful should the patient lose consciousness and allows the clinician to view the ECG immediately leading up to the event.

Traditionally, post event recorders would have had an external lead with electrodes fitted to the patient’s chest or be held against the chest to record. Recent advances in technology have seen the development of new recorders, which have built in finger or wrist watch type electrodes, which permit long term monitoring without the discomfort or irritation of a patient lead.

Ambulatory blood pressure monitors. Are you getting good value?

The cost of ABPM monitors has fallen considerably in recent years but purchasers should check that there are no hidden extras and that the supplier is able to offer free technical support, installation training and advice to nurses who generally fit the monitor.

As some manufacturers offer expensive additional warranties or support contracts the true “whole life” running costs including maintenance should be factored in to the purchasing decision.

All modern 24-hour monitors like the Meditech ABPM-04, Meditech ABPM-05 and TM-2430 now use PC-based software and in most instances it is possible to attach the patient’s report to popular clinical management systems, such as EMIS and SystmOne.

Again it is worth checking that this is included and that there are no expensive annual licence fees or dongles required, as well as checking that multiple copies can be installed without additional cost.

An ABPM report should include, as a minimum, daytime and night-time averages, a list of BP data and trend graph on one or 2 sheets of A4 paper.

Normal mean levels for ABPM in adults are slightly lower than surgery readings at 135/85 for daytime average and 120/70 when asleep.

The results can usually be interpreted by suitably qualified clinicians. The latest version of CardioVisions that works with the Meditech ABPM-04 and Meditech ABPM-05 provides additional automatic analysis to the NICE 2011 guidelines and this can save time and ensure consistent reporting.

Ideally, the monitor should be able to use rechargeable batteries to minimise costs. A wide range of cuff sizes should be available but the adult and large adult will probably be used the most popular. Cuff barriers like those from TIDI can help keep cuffs hygienic and prevent soiling.

Most but not all companies will offer additional training if required.

As with any piece of medical equipment used in patient diagnosis, routine calibration and servicing is important. This should only be undertaken by authorised service technicians that have access to original manufacturer parts and test equipment.

With any ABPM this should be available in the UK from the supplier to avoid unnecessary downtime.

As with all things it’s unwise to pay too much but sometimes risky to pay too little.

Undiagnosed OSA increases the risk of high blood pressure

Obstructive Sleep Apnoea (OSA) is a sleep related breathing disorder which occurs if airflow through the nose and mouth is obstructed. Having undiagnosed OSA increases the risk of high blood pressure, and is associated with other serious conditions such as strokes and heart attacks, type II diabetes and depression as well as traffic collisions. OSA affects men, women and children.

A growing amount of evidence suggests that OSA is the most common type of secondary hypertension, however, an estimated 70-90 percent of cases are undiagnosed.

The Meditech apneABP is ideal as an opportunistic outpatient screening tool for OSA and can help diagnose at risk patients prior to referral to specialist sleep labs.

Blood pressure is recorded automatically at pre-set intervals and SP02 data is recorded continuously.

The easy to use CardioVisions software displays 24-hr blood pressure chart, histogram, correlations, blood pressure statistics, oxygen saturation overview, plethysmograph pulse wave, pulse oximetry statistics and activity.

As a result, apneABP gives information not only about blood pressure and general pulse oximetry data, but also about the condition of the arterial system through plethysmograph and pulse wave.

The apneABP e will allow CCGs and GPs to take an active role in OSA screening and referral pathways which is beneficial to the patient, the GP and the sleep clinic.

PMS algorithm for blood pressure measurement

The CG127 2011 NICE Hypertension guidelines includes generic guidance on the measurement of blood pressure, including the key recommendation that 24 hour ambulatory blood pressure measurement be used before anti-hypertensive treatment is initiated. However out of the entire 317 page document, there is only one 6 page section on measuring blood pressure.

This section focuses on the different ways and methods of measuring blood pressure and the different types of devices available. The question is could the selection of the latest devices       streamline the blood pressure measurement process and save time, as well as clinical resources?

Is there a case for developing a suggested PMS algorithm for blood pressure measurement and what form should this take?

Step One Use a Waiting Room BP Monitor

Monitors like the TM-2655P waiting room monitor for patient self-measurement have been available for some time. They are convenient, easy to use and cost effective. They can be effective opportunistic screening devices and may identify patients with undiagnosed Hypertension.

Many also provide additional clinical information such as whether an Irregular Heartbeat is present. Many GP practices utilize them as part of a drop in service as they allow patients to monitor their own BP without making an appointment. This frees up clinicians for other duties. As with any BP monitor, it is important to check the monitor is listed on the BHS web site (www.bhsoc.org). Monitors that measure from the upper arm are recommended.

Step 2 Confirmation with a manual measurement

If it is felt that a reading from a waiting room blood pressure monitor needs clarification, an additional measurement should be taken. The BHS provide “best practice” guidance on the correct way to record blood pressure using an automatic or manual device. Most clinicians will rely on a clinically validated automatic monitor.

Most of these low cost devices like the UA-1010 feature an irregular heartbeat indicator and some have a “Tricheck” feature, which will automatically repeat a measurement three times, in accordance with BHS recommendations.

For patients identified with an irregular heartbeat, non-Mercury manual devices like the UM-101 are available.

Step 3 Use ABPM – The Gold Standard

The cost of ambulatory blood pressure monitors has fallen considerably over the last few years.  Like spirometers and ECG machines, the latest models such as the Meditech ABPM-05 feature software that provides automatic analysis of the results for consistent, time saving reporting to NICE Guidelines.

No More New Mercury Sphygmomanometers

The confusion that has surrounded the use of Mercury in medical devices has been rumbling on for several years. It’s use was restricted in thermometers some years ago but 2014 now finally sees the banning of it in new Mercury sphygmomanometers for environmental reasons.

The sale of Mercury Sphygmomanometers is now banned under EU directive no 847/2012 which also bans the use of Mercury strain gauges.

Alternatives to the Mercury sphygmomanometer and Mercury strain gauge are widely available, in the case of strain gauges they now use Indium Gallium.

The highly popular validated A&D UM-102A offers Auscultatory manual blood pressure measurement without Mercury in a compact design it even looks like a Mercury sphygmomanometer! Hybrid automatic and manual sphygmomanometers like the A&D Medical  UM-211 are also available.

Interestingly enough the directive does allow the use of Mercury as a reference standard for the validation of new blood pressure monitors and for research. So the Gold Standard still lives on since it’s invention over 130 years ago in 1881!