Relationship between fragmented QRS complexes and left ventricular systolic and diastolic functions.

BACKGROUND: Fragmented QRS complexes (fQRS) have been associated with increased morbidity and mortality, sudden cardiac death, and recurrent cardiovascular events. The association between left ventricular systolic and diastolic functions and presence of fragmented QRS has not been comprehensively studied to date. We tested the hypothesis that the presence of fragmented QRS is associated with left ventricular systolic and diastolic dysfunction.

METHODS: The study included 259 patients who were consecutively admitted to our outpatient clinic for cardiovascular risk factor management. Extensive echocardiographic parameters were obtained from all patients and these were compared with the presence and number of fQRS.

RESULTS: Patients with fQRS were of older age (58 ± 12 vs. 55 ± 13 years, p = 0.03) and had prolonged QRS time (105 ± 12 vs. 93 ± 10 ms, p < 0.001) and a higher rate of Q waves on ECG (36% vs. 11%, p < 0.001). In addition, they had worse systolic (lower LVEF%, 44 ± 17 vs. 61 ± 12, p < 0.001) and diastolic functions (DT, 177 ± 77 vs. 211 ± 59 ms, p < 0.001; IVRT, 81 ± 27 vs. 92 ± 22 ms, p = 0.001; Em, 9 ± 4 vs. 10 ± 4 cm/s, p = 0.008; E/Em ratio, 11 ± 5 vs. 8 ± 4, p < 0.001) in comparison to patients with nonfragmented QRS. There was a significant negative correlation between the number of fQRS and left ventricle systolic functions (for LVEF%, r = - 0.595, p < 0.001). After adjustment for age and gender, the number of fQRS remained significantly negatively associated with left ventricular systolic and diastolic functions.

CONCLUSION: We found that fQRS is related to left ventricular systolic dysfunction and diastolic dysfunction. fQRS, which may be the result of myocardial ischemia or scar on myocardial electrical parameters at the cellular level, may represent inadequate systolic and diastolic functions.