Significance of fragmented QRS complexes for identifying left ventricular hypertrophy in patients with hypertension

ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

ISE/ISHNE Expert Consensus Statement on ECG Diagnosis of Left Ventricular Hypertrophy: The Change of the Paradigm. The joint paper of the International Society of Electrocardiology and the International Society for Holter Monitoring and Noninvasive Electrocardiology

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria, i.e. the increased QRS complex amplitude in defined leads. The classical ECG diagnostic paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces. These increased forces are reflected in the augmented QRS amplitude in the corresponding leads. However, the clinical observations document increased QRS amplitude only in the minority of patients with LVH. The low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm.

Fragmented QRS complex on a 12-lead electrocardiogram predicts cardiovascular and all-cause mortality in dialysis patients

BACKGROUND

Cardiovascular disease (CVD) is the most common cause of mortality in end-stage renal disease (ESRD) patients. Fragmented QRS complex (fQRS) has been reported as a helpful marker in evaluating various cardiovascular pathologies. We aimed to investigate the value of the fQRS complex clinical decision of ESRD patients receiving dialysis.

METHODS

This prospective observational study included 411 patients receiving hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD) between 2016-01-01 and 2020-12-31. The primary outcomes were all-cause and cardiovascular (CV) mortality.

RESULTS

HD patients have elevated values of fQRS complex compared to CAPD patients (39.1% vs. 28.2%, P = 0.027). Significantly, fQRS complex in the anterior/lateral leads is associated with all-cause and CV mortality stronger than fQRS in the inferior leads (P = 0.008). In a multivariate Cox regression analysis, HD patients with fQRS complex had a higher incidence of all-cause mortality (hazard ratio [HR] = 1.860; 95% confidence interval [CI]: [1.032, 3.349]; p = 0.041) and CV mortality (HR = 2.989; 95% CI [1.357, 6.584]; p = 0.007). For CAPD patients, fQRS complex was also associated with increased risk of all-cause mortality (HR = 1.593; 95% CI [1.023, 2.580]; p = 0.049) and increased risk of CV mortality (HR = 2.392; 95% CI [1.348, 4.173]; p = 0.013).

CONCLUSIONS

The presence of the fQRS complex was an independent predictor of all-cause and CV mortality in HD and CAPD patients. We suggested a potential role of the fQRS complex in CV risk strata for dialysis patients and the choice of dialysis modality.

Certain beta blockers (e.g., bisoprolol) may be reevaluated in hypertension guidelines for patients with left ventricular hypertrophy to diminish the ventricular arrhythmic risk

Hypertensive left ventricular hypertrophy (HTN LVH) is associated with almost threefold increased risk of ventricular tachycardia (VT)/ventricular fibrillation (VF). Furthermore, HTN LVH increases the risk of sudden cardiac death (SCD). The reverse LV remodeling due to efficient antihypertensive therapy lowers the incidence rates of cardiovascular events and SCD and the vast majority of available arterial hypertension (HTN) guidelines recommend renin angiotensin system (RAS) blockers and calcium channel blockers (CCBs) for HTN LVH aiming for LVH regression. On the other hand, beta blockers (BBs) as a class are not recommended in HTN LVH due to their insufficient capacity to reverse LVH remodeling even though they are recommended as the first-line drugs for prevention/treatment of VT/VF (in general, unrelated to HTN LVH). Moreover, BBs are the best antiarrhythmic (against VT/VF) among antihypertensive drugs. Despite that, BBs are currently not recommended for LVH treatment in HTN Guidelines. It is important to prevent VT/VF in patients at high risk, such as those with HTN LVH. Therefore, certain BBs (such as Bisoprolol) may be reevaluated in guidelines for HTN (in the section of HTN LVH).

Assessment of Hypertension Using Clinical Electrocardiogram Features: A First-Ever Review

Hypertension affects an estimated 1.4 billion people and is a major cause of morbidity and mortality worldwide. Early diagnosis and intervention can potentially decrease cardiovascular events later in life. However, blood pressure (BP) measurements take time and require training for health care professionals. The measurements are also inconvenient for patients to access, numerous daily variables affect BP values, and only a few BP readings can be collected per session. This leads to an unmet need for an accurate, 24-h continuous, and portable BP measurement system. Electrocardiograms (ECGs) have been considered as an alternative way to measure BP and may meet this need. This review summarizes the literature published from January 1, 2010, to January 1, 2020, on the use of only ECG wave morphology to monitor BP or identify hypertension. From 35 articles analyzed (9 of those with no listed comorbidities and confounders), the P wave, QTc intervals and TpTe intervals may be promising for this purpose. Unfortunately, with the limited number of articles and the variety of participant populations, we are unable to make conclusions about the effectiveness of ECG-only BP monitoring. We provide 13 recommendations for future ECG-only BP monitoring studies and highlight the limited findings in pregnant and pediatric populations. With the advent of convenient and portable ECG signal recording in smart devices and wearables such as watches, understanding how to apply ECG-only findings to identify hypertension early is crucial to improving health outcomes worldwide.

Fragmented QRS as a Marker of Myocardial Fibrosis in Hypertension: a Systematic Review

PURPOSE OF REVIEW

Hypertension cause damage in cardiac structure and induce pathological myocardial fibrosis that leads to hypertensive cardiomyopathy. A narrow fragmented QRS complex (fQRS) is associated with myocardial fibrosis and scar tissue in various cardiovascular diseases. It is also associated with myocardial fibrosis in hypertensive patients even in the absence of any structural heart diseases. This article aimed to demonstrate importance and usefulness of fQRS in hypertensive patients.

RECENT FINDINGS

Current evidence suggest that the frequency of fQRS is significantly higher in hypertensive patients compared to normotensives. Also, fQRS seems to be a predictor of left ventricular hypertrophy, increased systolic blood pressure, non-dipping, deterioration of the left ventricular geometry, and worse systolic and diastolic functions in hypertensive patients. As a simple and easy detectable electrocardiographic finding, fQRS may indicate myocardial fibrosis, uncontrolled blood pressure, and deteriorated cardiac structure in hypertensive patients even in the absence of other structural heart diseases, and may also be useful to predict high-risk hypertensives.

Presence of fragmented QRS is associated with increased epicardial adipose tissue thickness in hypertensive patients

BACKGROUND

Epicardial adipose tissue (EAT) is a cardiometabolic risk factor, and its possible relationship with hypertension has been reported previously. Fragmented QRS (fQRS) detected on electrocardiography (ECG) has been demonstrated to be a marker of myocardial fibrosis. In this study, we aimed to investigate the relationship between the thickness of EAT, and presence of fQRS in hypertensive patients.

METHODS

Consecutive patients who were diagnosed with hypertension were included in the study. ECG and transthoracic echocardiography (TTE) were performed to all patients. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. Thickness of EAT was measured by TTE.

RESULTS

This study enrolled 69 hypertensive patients with fQRS on ECG and 45 hypertensive patients without fQRS as the control group. Age (P = .869), and gender distribution (P = .751) were similar in both groups. Left atrial diameter (P = .012), interventricular septal thickness (P < .001), posterior wall thickness (P < .001), left ventricular ejection fraction (P = .009), left ventricular mass (P = .006), left ventricular mass ındex (P = .014), left ventricular hypertrophy (P = .003), and EAT thickness (P < .001) were found to be significantly increased in patients with fQRS. In multivariate analysis, among these variables only EAT was observed to be an independent predictor of fQRS (odds ratio:3.306 [95% confidence interval, 0.030-0.118], P = .001).

CONCLUSION

A significant association exists between the presence of fQRS and EAT thickness in hypertensive patients. The presence of fQRS, just as EAT thickness, may be used as a cardiometabolic risk factor in hypertensive patients.

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 for Risk Stratification in Patients Undergoing First Diagnostic Coronary Angiography

Background

Only a small proportion of patients referred for coronary angiography with suspected coronary artery disease (CAD) have the diagnosis of obstructive CAD confirmed by the exam. For this reason, further strategies for risk stratification are necessary.

Objective

To investigate the relationship of the presence of fragmented QRS (fQRS) on admission electrocardiogram with angiographically detected CAD and CAD severity in patients without known vascular diseases and myocardial fibrosis, undergoing first diagnostic coronary angiography.

Methods

We enrolled 336 consecutive patients undergoing coronary angiography for suspected CAD. The patients were divided into two groups according to the presence or absence of fQRS on admission. We compared the groups regarding the presence and severity of CAD.

Results

Seventy-nine (23.5%) patients had fQRS on admission. There was not a statistically significant difference between patients with fQRS (41.8%) and non-fQRS (30.4%), regarding the presence of CAD (p = 0.059). However, there was a statistically significant difference between patients with fQRS and non-fQRS regarding the presence of stenotic CAD (40.5% vs. 10.5%, p<0.001) and multi vessel disease (25,3% vs. 5.1%, p<0.001). The frequency of fQRS was significantly higher in patients with SYNTAX score >22 compared to patients with SYNTAX score ≤22.

Conclusions

Our findings suggest that fQRS may be an indicator of early-stage myocardial damage preceding the appearance of fibrosis and scar, and may be used for risk stratification in patients undergoing first diagnostic coronary angiography

Usefulness of fragmented QRS in hypertensive patients in the absence of left ventricular hypertrophy

In the absence of left ventricular hypertrophy, importance of fragmented QRS complex (fQRS) in individuals with hypertension is unknown. The authors aimed to evaluate the relationship between blood pressure levels and fQRS in the absence of left ventricular hypertrophy. A total of 548 never-treated patients who underwent 24-hour ambulatory blood pressure monitoring were enrolled. The frequency of fQRS was significantly higher in patients with hypertension than normotension (36.4% vs 17.6%, P<.05). Multivariate logistic regression analysis revealed that systolic blood pressure is significantly associated with presence of fQRS on electrocardiography (odds ratio, 0.931; 95% CI, 0.910-0.9521 [P<.001]) even after adjusting for other confounding factors. Receiver operating characteristic analysis revealed a cutoff value of 147.65 mm Hg for systolic blood pressure to predict presence of fQRS (sensitivity: 51%, specificity: 99%, area under the curve=0.764; 95% CI, 0.717-0.811 [P<.001]). fQRS may be a sign of increased blood pressure and may predict higher fibrotic burden in patients with hypertension.

The effect of circadian blood pressure pattern on presence of fragmented QRS complexes in hypertensive subjects

The association of deteriorated circadian blood pressure (BP) variability with presence of fragmented QRS (fQRS) on electrocardiography (ECG) is not clear. The present study aims to evaluate the relationship of BP patterns with presence of fQRS on ECG. A total of 338 consecutive newly diagnosed and never treated hypertensive patients who are without left ventricular hypertrophy and underwent 24-hour ambulatory BP monitoring were enrolled. Patients were classified as dippers, nondippers, and reverse dippers according to ambulatory BP monitoring results. The groups were compared regarding frequency of fQRS on ECG. The frequency of fQRS was significantly higher in reverse dippers compared with dippers (37.7% vs. 20.6%, P = .013). In multivariate logistic regression analysis, nighttime systolic BP was found to be an independent predictor of fQRS on ECG (P < .001, 95% confidence interval = 0.901-0.955). Other predictors of fQRS were daytime diastolic BP and age. Furthermore, fQRS was found to be an independent predictor of reverse dipping BP pattern in hypertensive patients (P = .004, odds ratio: 2.416, 95% confidence interval = 1.327-4.396). In conclusion, as a marker of fibrosis and higher fibrotic burden within myocardium, fQRS may be useful to determine the high-risk hypertensive patients in the absence of left ventricular hypertrophy.

The relationship between fragmented QRS and non-dipper status in hypertensive patients without left ventricular hypertrophy

BACKGROUND

Fragmented QRS (fQRS) has been shown to be associated with poor outcome in various cardiovascular diseases. Non-dipper hypertension is also associated with increased cardiovascular mortality. The aim of our study is to investigate the relationship between fQRS and non-dipper status in hypertensive patients without left ventricular hypertrophy (LVH).

METHODS

This study included 106 hypertensive patients without LVH. Patients were divided into two groups: dipper hypertension and non-dipper hypertension. The presence of fQRS was analyzed from surface electrocardiography.

RESULTS

Frequency of fQRS (56% vs. 19.6%, p < 0.001) and mean number of leads with fQRS (1.9 ± 1.7 vs. 0.6 ± 1.0, p < 0.001) were significantly higher in patients with non-dipper hypertension compared to dipper hypertension. In addition, the number of leads with fQRS was positively correlated with systolic (r = 0.334, p < 0.001) and diastolic (r = 0.280, p = 0.004) blood pressures (BP). By a multivariate regression analysis, fQRS (OR: 5.207, 95% CI: 2.195-12.353, p < 0.001) was found to be independent predictor of non-dipper status.

CONCLUSION

fQRS is independent predictor of non-dipper status in hypertensive patients without LVH. Also, the higher number of leads with fQRS is associated with higher sleep systolic and diastolic BPs.

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.

Total Mortality, Major Adverse Cardiac Events, and Echocardiographic-Derived Cardiac Parameters with Fragmented QRS Complex

BACKGROUND

Fragmented QRS complex (fQRS), an easily evaluated noninvasive electrocardiographic parameter, is associated with worse outcomes in patients with several cardiovascular conditions. The presence of fQRS on ECG may be an indicator of myocardial damage in patients with coronary artery disease (CAD). In this article, we performed a meta-analysis in order to characterize the presence of fQRS on ECG in patients with CAD.

METHODS

We searched English-language randomized controlled trials involving fQRS on ECG in patients with CAD (n = 3279 patients, 12 trials). Two reviewers independently extracted data. Data on LVEF, LVESD, LVEDD, LVESV, LVEDV, total mortality, stroke, and MACE were collected. fQRS was performed a comparison with non-fQRS, calculating pooled relatives risk (RRs) and weighted mean difference (WMD), and associated 95% confidence intervals (CIs).

RESULTS

fQRS was associated with significant increased WMD of LVEDD (WMD, 2.26; 95%CI, 0.92 to 0.36, P = 0.0009), LVESD (WMD, 2.71; 95%CI, 1.23 to 4.19, P = 0.0003), LVEDV (WMD, 31.37; 95%CI, 24.82 to 37.92, P < 0.00001), and LVESV (WMD, 28.45; 95%CI, 22.92 to 33.98, P < 0.00001). As compared to non-fQRS, fQRS increased risk of total mortality (RR, 3.09; 95%CI, 1.76 to 5.44, P < 0.0001) and MACE (RR, 2.85; 95%CI, 1.98 to 4.09, P < 0.00001) in patients with CAD. However, a decreased trend was observed for LVEF (WMD, -3.59; 95%CI, -7.05 to -0.12, P = 0.04). For the incidence of stoke, there was no difference between fQRS and non-fQRS group.

CONCLUSIONS

Our findings indicate that fQRS is a valuable factor to predict total mortality and MACE in patients with CAD.