Fragmented QRS and subclinical left ventricular dysfunction in individuals with preserved ejection fraction: A speckle-tracking echocardiographic study

Introduction:Fragmented QRS (fQRS) complex on routine ۱۲-lead electrocardiogram (ECG) predicts adverse outcomes in patients with cardiovascular diseases. In addition, it has been found to be associated with subclinical myocardial dysfunction in chronic diseases. We sought to investigate the relationship between the presence of fQRS with the myocardial functions in individuals free from known systemic cardiovascular diseases.Methods:In a case-control study, we evaluated normal individuals from March ۲۰۱۷ to February ۲۰۱۸. All participants underwent a ۲-dimensional transthoracic echocardiographic examination using tissue Doppler imaging (TDI) and speckle-tracking echocardiography. In addition, all participants were examined using a ۱۲-lead surface ECG, and patients with fQRS and a group of age- and sex-matched controls without fQRS were enrolled in our study.Results :The patients' mean age was ۴۰.۳ ± ۱۰.۷ and ۳۵.۴ ± ۱۱.۲ years in fQRS-positive and fQRS-negative groups, respectively (P = .۱۱۰). Patients with fQRS had significantly lower values of apical left ventricular global longitudinal strain (LV GLS) in ۲-chamber (۱۶.۹ ± ۲.۵ vs. ۲۰.۵ ± ۳.۳, P < .۰۰۱), ۴-chamber (۱۶.۹ ± ۳.۴ vs. ۲۰.۱ ± ۳, P = .۰۰۱), LAX views (۱۷.۷ ± ۲.۸ vs. ۲۰.۸ ± ۳.۵, P = .۰۰۱), and averaged LV GLS (۱۷ ± ۲.۶ vs. ۲۰.۴ ± ۲.۷, P < .۰۰۱) values compared to patients without fQRS. In a multivariate analysis, averaged LV GLS and smoking history were independent predictors for positive fQRS.Conclusion :The presence of fQRS on ۱۲-lead ECG in healthy population was associated with lower values of LV GLS compared to normal individuals without fQRS.