eLetters

42 e-Letters

published between 2019 and 2022

  • S1Q3T3R3 left arm – V2 ECG lead misplacement

    Dear Editor,
    We read with interest Thomson et al’s article “ECG in suspected pulmonary embolism” which was published in Postgraduate Medical Journal in January 2019. We would like to bring to your attention another important but little-known cause of S1Q3T3, namely left arm – V2 ECG lead misplacement. This occurs when the yellow ECG cables are misplaced and can easily be misdiagnosed as a pulmonary embolism. A characteristic appearance occurs which we believe is pathognomonic for LA – V2 misplacement. In addition to S1Q3T3, a tall R wave in lead III is seen (1). In a study of 62 patients in whom we recorded both a normal and an LA V2 ECG lead misplacement, we observed that the presence of S1Q3T3R3 is highly statistically significant for left arm -V2 lead misplacement (P=0) (1). It is important to exclude lead misplacement, or the patient may have incorrect treatment administered or the correct treatment withheld because of an error in recording an ECG. Of 230 unrecognised ECG lead misplacements in our hospital, 10.9% were left arm – V2 (2).
    After a thorough search of the literature we have identified only 2 brief reports on this topic (3,4). Therefore, it is highly likely that if it does occur then ECG features will inadvertently be attributed to pulmonary embolism and managed inappropriately.

    1. Lynch R, Ballesty L, Kuan SC, Ponnambolam Y. Left arm – V2 ECG Lead Misplacement by Colour: a largely unknown entity which can easily be Misdiagnosed as a Pulmo...

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  • Overuse of imaging might be attributable to suboptimal clinical decision rules

    The judgment that imaging studies were over-utilised (1) should not be based on the degree of compliance with the Wells clinical decision rule (CDR), given the fact that the Wells score is not necessarily the optimal one for PE. In a study which compared 7 CDRs, namely, the Wells score, simplified Wells score, original Geneva score, revised Geneva score, Charlotte score and the Pisa model, diagnostic accuracy amounted to 0.44, 0.61, and 0.76 for simplified Wells score, Wells score, and Pisa model, respectively (2). The Wells score was tested in 598 primary care patients presenting with symptoms including cough, unexpected or sudden dyspnoea, deterioration in existing dyspnoea, and pleuritic pain, singly or in combination. These patients were referred to secondary care with suspected PE, where they were subsequently rigorously evaluated and investigated according to hospital guidelines. The diagnosis of PE was subsequently confirmed in 73 cases. However, in as many as 44 of those cases where PE was ruled out, the presenting Wells score amounted to >4 points (3), a score that is taken to signify "PE likely" in the simplified Wells score. In the evaluation of PE diagnostic confusion is compounded by the fact that PE can be an incidental finding, for example, during CT imaging in the oncological context (4). In the latter study, 25% of 52 patients with incidental PE had no PE-related symptoms (4). In the entire group of 52 patients with incidental PE, eight had m...

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