Relationship between fragmented QRS complex and left ventricular systolic and diastolic function in kidney transplant patients

Fragmented QRS complex is an independent predictor of plaque burden in patients at intermediate risk of coronary artery disease

OBJECTIVE

We aimed to evaluate the relationship between fragmented QRS complex and plaque burden in patients presented with typical chest pain and deemed to have intermediate pretest probability of CAD using coronary computed tomography angiography (CCTA).

METHODS

We studied electrocardiograms (ECGs) obtained from 172 subjects (47.5 ± 9.5 years, 125 were men) presented with chest pain and had intermediate pretest probability for CAD. The presence was found and evaluation of CAD was performed with CCTA.

RESULTS

Seventy four (43%) of the study cohort had CCTA-documented CAD. Meanwhile the frequency of fQRS in our cohort was (57%). 70 (71.4%) patients with fQRS had CAD compared with only 4 (5.4%) patients without fQRS (p < 0.001). The number of leads with fQRs was correlated with the calcium score (p < 0.005), segment stenosis score, segment involvement score, total plaque score (TPS), and E/e ratio (p < 0.001, for all). Multivariate analysis demonstrated that fQRS was a strong independent predictor for CAD (or = 2.15, p < 0.001). ROC analysis showed that the number of leads ≥3 was the optimal number for predicting CAD (AUC = 0.89, sensitivity 88%, and specificity 83%, p < 0.001).

CONCLUSION

Fragmented QRS was seen more often in patients with high plaque burden. We suggest that fQRS might provide a useful noninvasive prognosticator for subjects with intermediate pretest probability of CAD for further investigation.

Association between fragmented QRS and exercise intolerance in hypertensive patients: the relation with coronary flow

OBJECTIVE

We aimed to investigate the relation between the presence of fragmented QRS (FQRS) and exercise intolerance as assessed by 6 minute walking test (6MWT) and its association with coronary flow reserve (CFR).

METHODS

One hundred and twenty patients with hypertension (age: 47.3 + 6.9) who were never treated and without left ventricular hypertrophy underwent 6MWT. Echocardiographic examination was obtained for all patients. CFR was calculated as the hyperemic to baseline mean velocity ratio (hyperemia was induced by intravenous adenosine 0.14 mg/kg/min). Patients were stratified into one group with FQRS and another group without FQRS. Forty-eight normotensive subjects with a mean age of 45.7 + 5.3 were recruited and served as a control group.

RESULTS

The frequency of FQRS was 49% in hypertensive patients versus 2% in control subjects. Patients with FQRS had higher systolic blood pressure (p < .05; <.01), a significant lower 6MWTD (p < .001), increased LAVI (p <.05), increased E/e' ratio (p < .01) and lower CFR (p < .001) compared with those without FQRS and controls. FQRS was inversely correlated with CFR (-0.531; p < .001) and 6 MWTD (-0.415; p < .001) and positively correlated with E/e' (0.352, p < .02) and LAVI (0.296; p < .05). By a multivariate regression analysis, FQRS (OR = 6.13; p < .001) and CFR (OR = 3.28; p < .001) were the only two independent predictors for decreased 6 MWTD in hypertensive patients. Importantly the ≥3 cutoff number of leads was found to be the best predictor of CFR < 2.0 in hypertensive patients.

CONCLUSION

FQRS is frequent and an independent predictor of reduced exercise tolerance in hypertensive patients. More so, it is significantly associated with decreased CFR and left ventricular diastolic dysfunction. In light of these findings, fragmented QRS might be considered a simple marker for risk stratification of hypertensive patients.

Fragmented QRS complex is a prognostic marker of microvascular reperfusion and changes in LV function occur in patients with ST elevation myocardial infarction who underwent primary percutaneous coronary intervention

The present study aimed to investigate the in-hospital and long-term prognostic value of fragmented QRS complex (fQRS) for microvascular reperfusion and changes in left ventricular (LV) function in patients with ST elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI). A total of 216 patients with STEMI undergoing primary PCI were included in the current study. Patients were divided into two groups based on the presence (n=126) or absence (n=90) of fQRS following electrocardiograms (ECGs) on admission. Following primary PCI and follow up, patients were divided into four groups based on new onset, resolution, persistence and absence of fQRS. Major adverse cardiac events were defined to include cardiovascular death, arrhythmia, heart failure, reinfarction and target vessel revascularization. The percentage of patients with heart failure and microvascular reperfusion differed significantly between the fQRS(+) and fQRS(−) groups. Levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), Peak creatine kinase-MB (CK-MB) and Troponin I levels were observed to be significantly higher in the fQRS(+) group compared with the fQRS(−) group. In univariate logistic regression analysis, left ventricular ejection fraction (LVEF), NT-proBNP, Troponin I, Peak CK-MB and microvascular reperfusion were found to be associated with fQRS. Multivariate analysis identified that LVEF, NT-proBNP, Troponin I and microvascular reperfusion may be independent predictors of fQRS. The presence of fQRS was demonstrated to be associated with left ventricular dysfunction at follow up assessments. The presence of fQRS was not only significantly associated with myocardial microvascular reperfusion and left ventricular function, but was also a prognostic marker in STEMI.

Relationship between Fragmented QRS Complex and Aortic Stiffness in Chronic Hemodialysis Patients

OBJECTIVE

This study aimed to evaluate the correlation between fragmented QRS complex (fQRS), aortic stiffness, and diastolic dysfunction in hemodialysis patients.

SUBJECTS AND METHODS

A sample of 56 patients who received hemodialysis treatment was stratified into 2 groups according to their electrocardiography (ECG) patterns with or without fQRS. Baseline characteristics and laboratory parameters of patients were documented. Conventional echocardiographic and Doppler echocardiographic procedures were performed in all patients. The mean early (Em) diastolic and late (Am) diastolic myocardial velocities were calculated. These tests were performed before dialysis. The Student t test, Mann-Whitney U test, χ2 test, Spearman correlation, and multivariate linear regression analysis were used to analyze parameters where appropriate.

RESULTS

Of the 56 patients under hemodialysis, fQRS in ECG was detected in 26 (46.4%). Echocardiographic evaluation showed that deceleration time (237.57 ± 40.10 ms; p = 0.030), isovolumic relaxation time (126.84 ± 15.62 ms; p < 0.001), early (E)/late (A) ventricular filling velocity (E/A) ratio (1.15 ± 0.40; p ≤ 0.001), and aortic stiffness index value (9.62 ± 4.53; p = 0.016) exhibited a statistical increase in hemodialysis patients with fQRS compared to patients without fQRS. E (58.23 ± 19.96 m/s; p = 0.004), and Em (5.96 ± 2.08 cm/s; p = 0.023) velocity levels were significantly lower in hemodialysis patients with fQRS than patients without fQRS. Aortic stiffness closely correlated with diastolic dysfunction (deceleration time r = 0.273, p = 0.042; isovolumic relaxation time r = 0.497, p < 0.001; E/A ratio r = -0.449, p = 0.001). On multivariate linear regression analysis, fQRS and aortic stiffness were independently associated in hemodialysis patients (β = 0.321, p = 0.049).

CONCLUSIONS

Increased aortic stiffness and left ventricular systolic dysfunction were observed more frequently in hemodialysis patients with fQRS than in patients without fQRS. fQRS is an important determinant of aortic stiffness in hemodialysis patients.

[Fragmented QRS. Relevance in clinical practice]

The QRS complex represents the electrical depolarization of ventricular myocardium. In the case of an undisturbed depolarization, the QRS complex has a normal configuration and duration, but abnormal electrical conduction leads to widening of the QRS complex. The block of one of the Tawara branches results in a typical bundle branch block pattern. A QRS complex that cannot be classified as bundle branch block due to an atypical configuration and contains notched R or S waves is called a fragmented QRS. The underlying pathophysiologies are manifold and include myocardial scars induced by ischemic heart disease, myocardial fibrosis due to other diseases, primary cardiac pathologies as well as systemic diseases with cardiac involvement. Pathologies on the cellular level, such as ion channel dysfunctions, also correlate with fragmented QRS. Besides the diagnostic relevance, fragmented QRS is known to have prognostic properties, for example in identifying high risk patients with coronary artery disease, cardiomyopathy, Brugada syndrome and acquired long QT syndrome; however, fragmented QRS may also be detected in ECGs of healthy individuals.