Prognostic Value of Global Longitudinal Strain in Hypertrophic Cardiomyopathy: A Systematic Review of Existing Literature

Abstract Objectives The association of left ventricular global longitudinal strain (LV-GLS) with clinical outcomes in patients with hypertrophic cardiomyopathy (HCM) has been examined in multiple studies. The authors conducted a systematic review aimed at summarizing and critically appraising the current evidence. Background HCM is a common genetic cardiovascular disease with an estimated prevalence of 1 in 500 patients. LV-GLS derived from speckle tracking echocardiography is a sensitive noninvasive method of assessing regional left ventricular function. Several studies have suggested association of abnormal LV-GLS with outcomes in HCM patients. Methods A computerized literature search of all English language publications in the PubMed and EMBASE databases was made looking at all randomized and nonrandomized studies conducted on patients with HCM where association of LV-GLS with clinical outcomes was studied. We then manually searched the reference lists of included articles. The Preferred Reporting Items for Systematic reviews and Meta-Analyses statement (PRISMA) of reporting systematic reviews was used. Results Our search yielded a total of 14 observational studies published between 2009 and 2017 with a total of 3154 patients with HCM. Eleven of the 14 studies included a composite cardiac outcome which included mortality as their primary outcome of interest and 3 of the 14 studies looked at association of LV-GLS with ventricular arrhythmias and/or implantable cardiac defibrillator discharge. We noted wide variability in inclusion, methodology, follow-up, and consequently effect estimates, which was not conducive to performing a meta-analysis. However, despite the variation, all studies revealed a degree of association of abnormal LV-GLS with poor cardiac outcomes. Conclusions Our systematic review of more than 3000 HCM patients suggests an association of abnormal LV-GLS with adverse composite cardiac outcomes and ventricular arrhythmias.