2014, Volume 21, Issue 2, pages 41–80

In this issue we have some common themes. Four articles relate to the electrocardiogram (ECG) with the eminent Derek Rowlands and Philip Moore making a plea for formal ECG training for all doctors (see pages 47−8). Other articles cover Wolff-Parkinson-White syndrome (page 80), torsades de pointes (page 79) and Heather Wetherell continues her series on ECGs for the fainthearted highlighting whether we should trust our ECG machines (pages 62–3). 

Clinical estimation of the jugular venous pressure (JVP) has been at the heart of bedside cardiology for the past 100 years. Observation and description of the waveform used to be central to the derivation of a clinical diagnosis. As technology has rapidly developed over the past 25 years, the bedside method of JVP estimation and description has all but disappeared. But need it be abandoned? The conditions, which today cause an elevated JVP, are very different from those that were prevalent three decades ago. Rheumatic valve disease has all but disappeared in the UK, but heart failure caused by myocardial disease is now much more common. The outlook for patients with unoperated congenital heart disease was poor, but diagnostic and surgical advances in the last 50 years have made survival commonplace. Lifelong surveillance is required in all but the simplest cases. 

The first human electrocardiogram (ECG) was recorded over 125 years ago. Despite the development of many new investigative techniques, the ECG remains an essential part of any cardiovascular assessment, whether in relation to acute or chronic health issues, to insurance assessment or to the assessment of risk in critical occupations or in sports professionals. In terms of interpretation, it is fair to say that the ECG occupies a unique and unsatisfactory position. Unlike pathology specimens and the images produced by modern techniques (both of which are always formally reported by trained and tested professionals), and unlike biochemical data (which are usually presented to the user clinician with the normal values displayed), ECGs are most commonly reported and acted upon by front-line users who have had no formal training in, and no assessment of competency in, ECG interpretation, and who generally proceed with no clear guidelines about the limits of normality or the precise criteria for specific abnormalities. There is no formal, national programme for training in ECG interpretation, or for the assessment of ECG interpretation skills. Inevitably, therefore, the standard of ECG interpretation (both in general practice and also in hospital) is highly variable, and is often extremely poor.

Atrial fibrillation (AF) is a dangerous, prevalent condition whose first presentation may be ischaemic stroke. Anticoagulation dramatically reduces stroke risk if patients are first identified. While screening enhances AF detection, it is unclear whether opportunistic pulse palpation or systematic electrocardiogram (ECG) screening is superior.

Patients across 15 general practices in the Bradford and Airedale primary care trust aged over 65 years were invited for a limb-lead ECG. A total of 6,856 patients were subjected to an ECG. This study aimed to determine if screening improved AF detection and the prevalence of cardiac rhythms that may cause an irregular radial pulse.

There were 248 patients diagnosed with AF (3.6%): 153 out of 207 traceable patients were previously diagnosed, hence, screening increased AF detection by 26.1%. Further abnormalities capable of causing an irregular pulse (i.e. ectopy) were highly prevalent at 18.3%. Overall, 99.0% of recorded ECGs were interpretable.

In conclusion, limb-lead ECG screening improved detection rates in a simple and feasible screening strategy, avoiding the need for more costly and cumbersome 12-lead ECG screening. Furthermore, the high prevalence of ectopy suggests systematic ECG screening is more specific than opportunistic screening. This study demonstrates simple ECG models may have a promising potential role in improving AF detection, particularly if asymptomatic.

National Institute for Health and Care Excellence (NICE) CG95 guidelines recommend a diagnostic algorithm based on pre-test probability of significant coronary artery disease (SCAD). We hypothesised that these probabilities overestimate the risk of SCAD in our population leading to unnecessary invasive coronary angiography. 

Data were collected prospectively for every adult patient attending the rapid access chest pain clinic (RACPC) at a South London acute general hospital from 1 April 2012 to 31 March 2013. SCAD was defined as a luminal narrowing of ≥70% in a major coronary artery or >50% in the left main stem.

There were 551 people assessed with a mean age of 59.9 years; 52% were female. In total, 140 patients underwent coronary angiography. Of these, 79 patients fell within the 61–90% risk bracket, but only 32 (40.5%; 95% confidence interval [CI] 29.7–51.3%) had SCAD. Of patients undergoing angiography, 48 had a risk of >90% but only 26 (54.2%; 95% CI 40.1–68.3%) had SCAD. No individual component of the pre-test probability calculation (age, gender, typicality of symptoms, and cardiac risk factors) predicted an increased chance of SCAD. 

We conclude that NICE prediction tables overestimate the risk of SCAD in our patient population. We recommend that the risk tables be updated to represent contemporary patient cohorts in order to reduce the number of potentially unnecessary angiograms. 

Occupational radiation exposure in fluoroscopy-guided procedures is highest among medical staff, particularly cardiologists involved in interventional procedures. The danger of radiation-induced cataracts in operators, and the suggestion of a higher incidence of malignancy among interventional cardiologists, have led to a significant focus on radiation safety in the cardiac catheterisation laboratory. We examined our mean eye and tibia dosimeter reading trends between 1993 and 2011 (among different sub-specialised cardiologists), and the impact of shin tibia lead protectors. During the period 1993 to 2011 there was a steady decline in radiation doses. The dosimeter readings level fell from a peak of 34 to 6.0 mSv per year and 29 to 1.0 mSv per year at the eye and at the tibia, respectively. Interventional and electrophysiology/pacing cardiologists tend to have a trend of higher radiation doses at the tibia level as compared with non-interventional cardiologists. The introduction of shin leg protectors further reduced radiation exposure from a peak of 6.0 mSv per annum in 2008 to ≤1.0 mSv per annum. Radiation safety awareness and policies have led to a significant fall in operator radiation exposure. The shins, not protected by conventional lead aprons, receive a significant exposure. We have demonstrated that the routine wearing of shin protectors reduces radiation exposure to a minimal level.

The 2010 UK National Institute of Health and Care Excellence (NICE) guidelines for assessing patients with ‘chest pain of recent onset’ recommend coronary artery calcium scoring (CACS) to assess patients with a low risk of coronary artery disease (CAD) according to defined criteria. This study aims to evaluate the implementation of these guidelines in an area with a prevalence of CAD higher than the national average. 

Consecutive patients with recent onset stable chest pain were assessed by cardiologists in outpatient clinics at University Hospital Aintree, Liverpool, between January and December 2011. A total of 186 patients with a low risk of CAD underwent CACS and follow-on computed tomography coronary angiography (CTCA) if CACS <400. 

A CACS of zero was found in 94 patients and three of these were excluded due to motion artefacts. Of the remaining 91 patients, 75 (82.4%) had no visible atheroma, 10 (11%) had minor plaque, five (5.5%) had moderate disease and one (1.1%) had apparent severe disease, which was shown to be a false-positive result on subsequent invasive coronary angiography.

This study shows a negative predictive value for severe disease of 99% for a CACS of 0 in stable patients with a low pre-test probability of CAD. This supports the NICE guidelines, with CACS being the investigation of choice in the UK to rule out significant CAD in selected patient populations. The fact that almost half of all the patients referred for CTCA had a CACS of zero makes this a good quick rule-out tool and, hence, avoids the need for follow-on CTCA.

A 56-year-old male with no previous significant medical history initially presented to his general practitioner for a routine health check prior to starting a new occupation. An electrocardiogram (ECG) was taken that was found to be unusual and, hence, a referral to cardiology outpatients was made. Initial recommendation was made for ablation therapy based on the finding of Wolff-Parkinson-White (WPW) syndrome. After a successful procedure, the patient developed significant palpitations with haemodynamic compromise that required emergency direct current (DC) cardioversion. Subsequent re-investigation found a previously unmasked uncommon form of accessory tachyarrhythmia. This case report highlights the finding of Mahaim pathway in a patient initially treated for WPW syndrome.

Atrial fibrillation (AF) is the most common sustained arrhythmia faced by clinicians in primary and secondary care. Patients with AF face a significant risk of stroke and thromboembolic complications with associated morbidity and mortality. The role of antiplatelet agents is diminishing, while the use of oral anticoagulants is being actively encouraged. Warfarin has provided the mainstay of oral anticoagulation for more than half a century. New oral direct inhibitors (ODIs) of thrombin and activated factor X – commonly referred to as the new oral anticoagulants (NOACs) – are being prescribed with increasing frequency. These ODIs have a number of advantages over warfarin, including predictable response, no need for monitoring or dose changes and fewer drug and food interactions. Although the risk of intracranial bleeding is reduced, there is still a risk of major haemorrhage as patients are fully anticoagulated. An understanding of the ODIs’ metabolism and excretion, as well as their effects on coagulation tests, is paramount to the management of patients, particularly in emergency situations.

The possible overuse of coronary angiography in the investigation of suspected coronary artery disease has been raised as a concern in the literature. We examined our own coronary angiography database to assess the diagnostic yield from angiography in the investigation of patients with suspected coronary artery disease and also the subsequent rate of referral for revascularisation. Some coronary artery disease was found in 66% of patients. However, in spite of an overall diagnostic yield in keeping with National Institute for Health and Care Excellence (NICE) guidelines, only 28% of patients were referred for any form of revascularisation. The optimal use of coronary angiography has important resource implications and the rate of revascularisation may be a useful quality metric.

Heart failure (HF) accounts for 5% of all emergency hospital admissions in the UK. To ensure cost-effectiveness, the potential for any intervention to reduce admissions must be balanced against its required investment. This economic analysis compared cost-effectiveness of home- versus hospital-based exercise training as delivered within a randomised-controlled trial (RCT) for HF. The additional costs of delivering eight weeks of home- versus hospital-based training for 46 people with HF, within an established cardiac rehabilitation service, were balanced against emergency hospital admission costs incurred by home-training (n=15), hospital-training (n=15) and control (n=16) groups over five years.  The total cost of home-training was £3,244.47 (£196.53 per patient) – much of which was a fixed cost attributed to producing the home-training package. Hospital-training cost £3,656.06 (£221.58 per patient). Over five years, total admission costs for controls (of £157,305.23) were considerably higher than for both home- (£115,735.43) and hospital- (£108,117.51) training groups.  In conclusion, both training programmes incurred similar costs, which were offset by a reduction in emergency admission costs, compared with controls. Although hospital-training offered greater potential for reducing admission costs, with larger patient numbers, the cost of home-training per patient would decrease, increasing its likelihood of being the more cost-effective option.

We present a rare case of cardiac arrest caused by torsades de pointes in relation to severe hypothyroidism, which highlights the importance of thyroid replacement therapy compliance.