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 12‐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 2017 to February 2018. All participants underwent a 2‐dimensional transthoracic echocardiographic examination using tissue Doppler imaging (TDI) and speckle‐tracking echocardiography. In addition, all participants were examined using a 12‐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 40.3 ± 10.7 and 35.4 ± 11.2 years in fQRS‐positive and fQRS‐negative groups, respectively ( P = .110). Patients with fQRS had significantly lower values of apical left ventricular global longitudinal strain (LV GLS) in 2‐chamber (16.9 ± 2.5 vs. 20.5 ± 3.3, P < .001), 4‐chamber (16.9 ± 3.4 vs. 20.1 ± 3, P = .001), LAX views (17.7 ± 2.8 vs. 20.8 ± 3.5, P = .001), and averaged LV GLS (17 ± 2.6 vs. 20.4 ± 2.7, P < .001) 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 12‐lead ECG in healthy population was associated with lower values of LV GLS compared to normal individuals without fQRS.