Association between fragmented QRS complexes and left ventricular dysfunction in healthy smokers

OBJECTIVE: Smoking is a known risk factor for cardiovascular diseases and may cause myocardial damage independently of coronary artery disease. Fragmented QRS (fQRS) is an important marker of myocardial fibrosis, while speckle-tracking echocardiography is a method used to show subclinical left ventricle dysfunction. METHODS: Our study included 230 healthy individuals aged 18-40 years. The patients included were separated into two groups: those smokers (n = 130) and non-smokers (n = 100). After that healthy smokers group were divided into two groups: those with fQRS (n = 24) and those without (n = 106). In both groups, the arithmetic mean of three images was used to obtain the left ventricle global longitudinal strain (LV-GLS). The E/SRe ratio was also calculated and analyzed. RESULTS: There were significant differences between the smokers and non-smokers in terms of, E/SRe (55.7 ± 17.9 vs 50.3 ± 14.8; P = 0.015), LV-GLS (23.1 ± 1.9 vs 24.0 ± 1.7; P = 0.001), and fQRS (18.5% vs 6%; P = 0.005). As a result of subgroup analysis, pack-year history was higher in the fQRS positive group (16.7 ± 3.7 vs 11.2 ± 3.7, P < 0.001). While a negative correlation was observed between pack-year history and LV-GLS (r = -0.678, P < 0.001), there was a positive correlation between pack-year history and E/SRe (r = 0.730, P < 0.001). CONCLUSION: In conclusion, our study demonstrated that fQRS is a parameter that can be used to determine left ventricle subclinical systolic and diastolic dysfunction in smokers, and that left ventricle dysfunction is related to the duration and intensity of smoking.