Terminal QRS distortion

Terminal QRS distortion is present in anterior myocardial infarction but absent in early repolarization

Lee. @smithECGBlog. The American Journal of Emergency Medicine;2016;34(11):2182-2185

Clinical Question

  • In patients with benign early repolarisation, is there the absence of terminal QRS distortion on the ECG?

Background

  • For patients who present with chest pain, it can be difficult to distinguish between ECG findings of benign early repolarisation (BER) and left anterior descending artery occlusion (LADO)
  • Terminal QRS distortion has been reported to be present in a number of patients presenting with LADO
  • This trial investigated whether terminal QRS distortion was also present in patients with BER

Design

  • Retrospective observational cohort study
  • Secondary analysis
  • Terminal QRS distortion defined as the absence of both of the following in V2 and/or V3
    • S wave
      • Any deflection at the end of the R wave that dipped below the level of the PQ junction
    • J wave
      • Any positive deflection (notching or slurring) above the level of the ST segment at the J point
  • If patient had multiple ECGs only 1st ECG analysed
  • 2 reviewers reported ECGs, not blinded to study objectives

Setting

  • Single centre, USA
  • Data collected from 2003 – 2005

Population

  • Inclusion:
    • Patients presented to ED with chest pain
    • Admitted and ruled out for MI with serial troponins – 3 serial negative Troponin I (all below the reference value)
    • Had cardiologist confirmed interpretation of ER on the ECG
  • Exclusion:
    • <1mm ST elevation in any of leads V2 – V4
  • 242 patients found to have early repolorisation and a clinical picture of non-ischaemic chest pain
  • 71 patients excluded as <1mm ST elevation
  • Mean age 38 years
  • 86% male

Outcome

  • Primary outcome:
    • Terminal QRS distortion was absent in 100% of patients with benign early repolorisation (95% CI 97.8-100%)
  • Secondary outcomes: In patients with BER
    • S wave absent in
      • 0.6% in lead V2
      • 9% in lead V3
    • J wave absent in
      • 95% in lead V2
      • 83% in lead V3
  • When a J wave was present the S wave was significantly smaller amplitude
    • Median S wave amplitude with J wave present vs without J wave present
      • V2: 4 vs 14.5mm, P=0.004
      • V3: 0 vs 9mm, P<0.0001

Authors’ Conclusions

  • The presence of any terminal QRS distortion was 100% specific to acute MI

Strengths

  • Use of two reviewers
  • All patients included were admitted and had serial troponins
  • Clearly defined criteria for assessing terminal QRS distortion

Weaknesses

  • Retrospective
  • Single centre
  • Did not investigate patients presenting with other causes of ST elevation e.g. pericarditis, left ventricular hypertrophy
  • ECG readers were not blinded to study objective
  • Small data set compared to the large number of ECGs that are taken daily worldwide
  • Full patient demographics not available, and at first glance it is a limited data set (average age 38, and 86% male)- as age, sex, body habitus and ethnicity may all contribute to ECG patterns, a limited pool of patients could have biased the results

The Bottom Line

  • In patients that have benign early repolorisation there is the absence of terminal QRS distortion
  • The vast majority of patients with BER had a S wave that was present in V2 and/or V3; and those that did not have a S wave always had a J wave
  • If a patient has an absence of a S wave and a J wave in V2/V3 then the diagnosis of BER is very unlikely and based on previous research the diagnosis of acute MI should strongly be considered

External Links

Metadata

Summary author: @davidslessor
Summary date: 16/02/22

Peer reviewer: Segun Olusanya

 

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