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EDITORIALS: Beth Abramson Electrocardiography in suspected angina BMJ 2008; 337: a2340 [Full text]

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Lead Placement in ECGs

Richard A Hutchinson   (28 November 2008)

Cost effective investigation of suspected angina

S Richard Underwood, Royal Brompton Hospital, Sydney St, London SW3 6MP   (30 November 2008)

Lead Placement in ECGs 28 November 2008
Richard A Hutchinson, Paediatrics ST1 University Hospital Lewisham. SE13 6LH Send response to journal: Re: Lead Placement in ECGs	Your article on the prognostic value of rest and exercise ECGs in suspected angina demonstrates the importance of effective history and examination skills in formulating a diagnosis. However, much as a making a correct clinical diagnosis is dependent on the expertise and experience of the clinician making the assessment, so the validity of diagnostic tests is dependent upon the competence of the professional performing them. Your front cover demonstrates the chest wall electrodes of an ECG. Whilst orientation of the picture prohibits full interpretation, it can be clearly seen that V3 occupies a position aberrant to that of the standard position (the midpoint between V2 and V4), that V4 itself is mislocated from its standard position (5th intercostal space in the mid-clavicular line, or approximately just below the nipple in men), and that the lateral chest leads proceed on a path curvng upwards to the left axilla, when they should all lie on the same plane as V4. There has been a recent article comparing the reliability of ECG lead placement between different groups of health professionals, which demonstrated grave misunderstanding of the correct lead placements for ECGs, particularly with regard to leads V1 and V2 (often placed incorrectly in the parasternal 2nd intercostal spaces), and the left lateral chest leads, which were placed too high. More worryingly, the level of misunderstanding was highest in physicians (only 31% demonstrating correct V1 placement), and especially cardiologists (only 16% demonstrating correct V1 placement), compared to cardiac technicians (90% correct), and nursing staff (49% correct). How senior was the cardiologist performing the ECG on the front cover?! Reference: Rajaganeshan R et al. Accuracy in ECG lead placement among technicians, nurses, general physicians and cardiologists. Int J Clin Pract. 2008 Jan;62(1):8-9. Competing interests: None declared
Cost effective investigation of suspected angina 30 November 2008
S Richard Underwood, Professor of Cardiac Imaging Imperial College London, Royal Brompton Hospital, Sydney St, London SW3 6MP Send response to journal: Re: Cost effective investigation of suspected angina	In her editorial accompanying the cohort study of the incremental prognostic power of the stress ECG in the initial assessment of patients with suspected angina (1) Beth Abramson concludes that the stress ECG is a necessary extension of clinical assessment despite the fact that it carries little additional prognostic information over clinical assessment. She also acknowledges that stress imaging of myocardial perfusion and left ventricular function have greater predictive power but that these tests may be an unnecessary expense for routine use. No doubt this conclusion is based upon the widespread availability of the exercise ECG and the more limited availability of good quality imaging of coronary function. It would be interesting to speculate how the exercise ECG would fare in the sort of technology appraisal to which more modern technologies have been subjected. Although the exercise ECG is widely available and comparatively cheap, its diagnostic power is limited and, as we have seen, its incremental prognostic power over clinical assessment is poor. In contrast NICE found myocardial perfusion scintigraphy (MPS) to be both effective and cost effective for the assessment of patients presenting with possible stable angina (2) The evidence for its cost-effectiveness comes from both clinical and modelling studies, which have shown that a strategy of investigation that omits the exercise ECG and goes straight to MPS is cost effective, particularly in the intermediate likelihood patients who are commonly seen in the rapid access chest pain clinic (3). Similarly, in the lower likelihood patients cost effective practice is to follow an initial exercise ECG with MPS if further investigation is required. It is therefore understandable but not entirely evidence-based to conclude that the cheap and cheerful exercise ECG might be the best initial investigation in the majority of patients. The practicalities of investigation in most healthcare systems mean that it is likely to remain a common initial test even when other tests may be preferable in clinical and financial terms. There are those, however, who are working hard to ensure that the choice of investigation is based more on effectiveness and cost-effectiveness than on more random issues such as availability and clinician experience. The study by Neha Sekhri and colleagues may be another important step in allowing us to base our choice of investigations in these patients on firm evidence. 1 Abramson B. Electrocardiography in suspected angina. BMJ 2008; 337: a2340 2 National Institute for Clinical Excellence. Technology appraisal 73. Myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction. http://www.nice.nhs.uk/ta073. Accessed 30 November 2008. 3 Underwood SR, Anagnostopoulos C, Cerqueira M, et al. Myocardial perfusion scintigraphy: the evidence. Eur J Nucl Med Mol Imaging 2004; 31: 261-91 Competing interests: None declared