The Prevalence of Pathologic Q Waves on Electrocardiograms of Pediatric Patients with Confirmed Hypertrophic Cardiomyopathy: A Systematic Review of the Literature
Authors:   Division of Pediatric Emergency Medicine, Department of Emergency Medicine, University of South Alabama, Mobile, AL, USA, Mellick Larry B. , Singhapakdi Kanya ,   Department of Pediatrics, University of South Alabama, Mobile, AL, USA, Clanton Clista ,   Baugh Biomedical Library, University of South Alabama, Mobile, AL, USA, Waldrop Ronnie ,   Division of Pediatric Emergency Medicine, Department of Emergency Medicine, University of South Alabama, Mobile, AL, USA
Published: January 2023

Objectives The electrocardiogram (ECG) of patients with hypertrophic cardiomyopathy (HCM) ranges from normal to exhibiting evidence of ventricular hypertrophy, including pathologic Q waves and ST-T wave changes. Deep Q waves in the inferior and lateral leads are one of the classic ECG findings associated with HCM. The prevalence or frequency of this finding in pediatric HCM patients, however, is not well-established. Furthermore, other pediatric health conditions have also been associated with pathologic and non-pathologic Q waves and an awareness of those conditions is important to consider when Q waves are observed. The primary goal of this systematic review of the literature is to describe the prevalence of pathologic Q waves in the ECGs of pediatric patients with echocardiogram proven HCM. A secondary goal is to review other pediatric conditions that can present with pathologic and non-pathologic Q waves. Methods The databases PubMed, Web of Science, Scopus and cumulative index to nursing and allied health literature (CINAHL) were searched utilizing the preferred reporting items for systematic reviews and meta-analyses (PRISMA) format. The Rayyan systemic review software was used to screen articles for final review. The initial search (Search 1) consisted of the following terms: “dagger Q wave”, “dagger-like Q waves”, “dagger shape Q waves”. Subsequently, a broader search (Search 2) was conducted to determine if viable articles were omitted in the first search. This broader search strategy eliminated the term “HCM”. The authors then performed detailed review of the articles these two searches yielded, as well as a review of the references of these articles to find other relevant articles as well as produce a list of other pediatric conditions that may be associated with pathologic or nonpathologic Q waves. Results Of the articles found via the three searches, a total of nine English language articles that specifically addressed the prevalence of pathological Q waves in pediatric HCM patients were ultimately included in our systematic review. These nine articles described a total of 845 pediatric patients with HCM. Of these, 258 (30.5%) demonstrated pathological Q waves on their electrocardiograms. The range of percentages reported for pathological Q waves was 12.5 to 66.7%. Additionally, our review found fifteen different pediatric conditions reported to be associated with pathologic or non-pathologic Q waves. Conclusion Our systematic review confirmed that pathologic Q waves are a common and early electrocardiographic finding in children with HCM and may, in fact, be the only ECG finding. In addition, our review provided an extensive list of other pediatric diseases and conditions associated with pathologic or non-pathologic Q waves on the electrocardiogram.