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

The mechanism of lncRNA PVT1 targeting the miR-30a/Beclin-1 axis to mediate ventricular remodeling in spontaneously hypertensive rats

OBJECTIVES

Hypertension poses a great health threat globally. We probed the mechanisms of long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1) mediating ventricular remodeling (VR) in spontaneously hypertensive rats (SHR).

METHODS

PVT1 was down-regulated or miR-30a was inhibited in SHR in vivo. Hypertensive injury model was established in vitro. VR, fibrosis and autophagy-related indicators were detected by echocardiography, HE/WGA/Masson staining, ELISA, and immunohistochemistry. Cell viability, fibrosis markers, autophagy-related markers, and lncRNA PVT1 and miR-30a levels were assessed. Interactions between PVT1, Beclin-1 and miR-30a were verified.

RESULTS

PVT1 was up-regulated in myocardial tissues of SHR. PVT1 knockdown alleviated VR and myocardial fibrosis (MF) in SHR, as evidenced by decreased systolic blood pressure, left ventricular end-systolic diameter, left ventricular end-systolic diameter, and heart weight index, boosted left ventricular fractional shortening and left ventricular ejection fraction, abated inflammatory infiltration of myocardial tissues, decreased myocardial hypertrophy and interstitial fibrosis, reduced serum angiotensin II (Ang II) and atrial natriuretic peptide, and downregulated collagen I, collagen II, α-smooth muscle actin, and fibronectin protein. PVT1 knockdown down-regulated Beclin 1 and LC3B-II/LC3B-I and up-regulated p62 protein. In vitro, PVT1 knockdown improved fibrosis by inhibiting Ang II-induced cardiomyocyte autophagy. PVT1 acted as a competitive endogenous RNA to competitively bind to miR-30a to target Beclin-1 expression. PVT1 targeted the miR-30a/Beclin-1 axis to mediate autophagy to affect VR and MF in SHR.

CONCLUSIONS

LncRNA PVT1 promotes cellular autophagy by targeting the miR-30a/Beclin-1 axis, thereby promoting VR and MF in SHR. Knockdown of lncRNA PVT1 attenuates VR and MF in SHR.

Prevalence of electrocardiographic markers associated with myocardial fibrosis in masters athletes: a cohort study

Objectives

Myocardial fibrosis (MF) is associated with an increased predisposition to adverse cardiac events. The accumulation of high-volume and high-intensity exercise over an extended duration potentially increases the risk of MF. Specific electrocardiographic markers have been correlated with the presence of MF. This study assessed the prevalence of MF-related electrocardiographic markers in a Track and Field Master Athletics Cohort (TaFMAC).

Methods

Twelve-lead resting electrocardiograms (ECGs) were conducted on 155 athletes (90 males and 65 females) participating in the World Masters Athletics 2022. The ECG markers associated with MF, including pathological Q waves, inverted T waves, fragmented QRS complex, and prolonged QRS complex, were compared among different athletic specialities (endurance athletes n=51, sprinters n=69 and strength and power n=35).

Results

Overall, 71 instances of MF-related markers were identified from 155 ECG recordings (46%). Fragmented QRS emerged as the most common marker, with a prevalence of 29% in endurance and strength and power athletes, and 35% in sprinters. No significant group differences were observed in the prevalence of MF markers, whether analysed collectively (p=0.467) or individually (pathological Q waves p=0.367, inverted T waves p=0.309, fragmented QRS complex p=0.747 and prolonged QRS complex p=0.132).

Conclusions

The prevalence of MF markers, as determined by resting ECG, was evident in nearly half of masters athletes, irrespective of sex and sporting specialisation. These findings suggest resting ECG as a promising non-invasive method for the early identification of MF in athlete's hearts.

Riboflavin ameliorates pathological cardiac hypertrophy and fibrosis through the activation of short-chain acyl-CoA dehydrogenase

Short-chain acyl-CoA dehydrogenase (SCAD), the rate-limiting enzyme for fatty acid β-oxidation, has a negative regulatory effect on pathological cardiac hypertrophy and fibrosis. FAD, a coenzyme of SCAD, participates in the electron transfer of SCAD-catalyzed fatty acid β-oxidation, which plays a crucial role in maintaining the balance of myocardial energy metabolism. Insufficient riboflavin intake can lead to symptoms similar to short-chain acyl-CoA dehydrogenase (SCAD) deficiency or flavin adenine dinucleotide (FAD) gene abnormality, which can be alleviated by riboflavin supplementation. However, whether riboflavin can inhibit pathological cardiac hypertrophy and fibrosis remains unclear. Therefore, we observed the effect of riboflavin on pathological cardiac hypertrophy and fibrosis. In vitro experiments, riboflavin increased SCAD expression and the content of ATP, decreased the free fatty acids content and improved PE-induced cardiomyocytes hypertrophy and AngⅡ-induced cardiac fibroblasts proliferation by increasing the content of FAD, which were attenuated by knocking down the expression of SCAD using small interfering RNA. In vivo experiments, riboflavin significantly increased the expression of SCAD and the energy metabolism of the heart to improve TAC induced pathological myocardial hypertrophy and fibrosis in mice. The results demonstrate that riboflavin improves pathological cardiac hypertrophy and fibrosis by increasing the content of FAD to activate SCAD, which may be a new strategy for treating pathological cardiac hypertrophy and fibrosis.

Heart failure in systemic right ventricle: Mechanisms and therapeutic options

d-loop transposition of the great arteries (d-TGA) and congenitally corrected transposition of the great arteries (cc-TGA) feature a right ventricle attempting to sustain the systemic circulation. A systemic right ventricle (sRV) cannot support cardiac output in the long run, eventually decompensating and causing heart failure. The burden of d-TGA patients with previous atrial switch repair and cc-TGA patients with heart failure will only increase in the coming years due to the aging adult congenital heart disease population and improvements in the management of advanced heart failure. Clinical data still lags behind in developing evidence-based guidelines for risk stratification and management of sRV patients, and clinical trials for heart failure in these patients are underrepresented. Recent studies have provided foundational data for the commencement of robust clinical trials in d-TGA and cc-TGA patients. Further insights into the multifactorial nature of sRV failure can only be provided by the results of such studies. This review discusses the mechanisms of heart failure in sRV patients with biventricular circulation and how these mediators may be targeted clinically to alleviate sRV failure.

Electrocardiographic Patterns of Depolarization Abnormalities Help to Identify Reduced Left Ventricular Ejection Fraction

The aim of the study was to investigate the relationship between a decrease in the left ventricular ejection fraction (EF) and traditional ECG signs associated with structural changes of the myocardium (pathological Q wave, ventricular arrhythmias) and relatively new and poorly understood (fragmented QRS complex (fQRS), early repolarization pattern (ERP)) and evaluate their significance for identifying patients with mildly reduced EF (mrEF). The study included 148 patients who were treated and examined at the Almazov Medical Research Center. FQRS, ERP, pathological Q wave, and premature ventricular contractions (PVC) were described in the analysis of the ECG, and the results of echocardiography and statistical data were analyzed: Fisher’s test and chi-square, correlation analysis, and ROC analysis. According to the level of EF, patients were divided into three groups: group 1—patients with low EF (lEF) (less than 40%), group 2—patients with mildly reduced EF (mrEF) (40–49%); group 3—patients with preserved EF (pEF) (more than 50%). In the first group (EF), fQRS was registered in 16 (51.6%) patients, in the mrEF in 16 (18.2%). Pathological Q wave was detected in lEF in 20 (65%), in mrEF in 10 (35%), 15 (18%), in pEF in 15 (18%). The fQRS has been found to be more important in identifying patients with mrEF. In lEF in 2 (6.5%) patients, in mrEF in 2 (6.9%), in pEF in 11 (12.5%). There was no relationship between ERP, the amount of PVC, and the presence of ventricular tachycardia with EF. FQRS is significantly more common occurred with a decrease in EF and may be a marker of a mrEF. Thus, fQRS is associated with mrEF and pay close attention in routine clinical practice to identify patients at high risk of developing systolic dysfunction.

High prevalence of fragmented QRS on electrocardiography in Japanese patients with diabetes irrespective of metabolic syndrome

AIMS/INTRODUCTION

Fragmented QRS (fQRS) on electrocardiography is a marker of myocardial fibrosis and myocardial scar formation. This study aimed to clarify the relationship of fQRS with diabetes mellitus and metabolic syndrome (MetS) in Japanese patients.

MATERIALS AND METHODS

Approximately 702 individuals who had a routine health checkup at the Hokuriku Health Service Association (Toyama, Japan) in October 2014 were enrolled and categorized into one of the following four groups based on MetS and diabetes mellitus status: with diabetes mellitus (+) MetS+ (164 participants); diabetes mellitus+ without MetS (Mets-; 103 participants); diabetes mellitus- MetS+ (133 participants); and diabetes mellitus- MetS- (302 participants). fQRS was assessed using the results of electrocardiography.

RESULTS

The prevalence of fQRS was statistically higher in patients with diabetes mellitus+ MetS+ (37%) and diabetes mellitus+ MetS- (35%), than those with diabetes mellitus- MetS+ (14%) or diabetes mellitus- MetS- (10%; P < 0.0001). Significant differences were observed between the fQRS(+) and fQRS(-) groups for age, sex, waist circumference, heart rate, hypertension, hemoglobin A1c, total cholesterol, MetS and diabetes mellitus. The area under the receiver operating characteristic curve for traditional risk factors and diabetes mellitus was 0.72 (P = 0.0007, 95% confidence interval 0.67-0.76), and for traditional risk factors and MetS it was 0.67 (P = 0.28, 95% confidence interval 0.62-0.72). Patients with diabetes mellitus had more than threefold higher likelihood of showing fQRS (odds ratio 3.41; 95% confidence interval 2.25-5.22; P < 0.0001) compared with the reference group without diabetes mellitus, after adjusting for age, sex, dyslipidemia, hypertension and waist circumference.

CONCLUSIONS

fQRS was observed more frequently in diabetes mellitus patients than in MetS and control individuals. Diabetes mellitus was the most significant determinant for fQRS among MetS and other traditional metabolic risk factors.

Prognostic Significance of Fragmented QRS in Patients with Acute Ischemic Stroke

OBJECTIVES

There are studies in the literature showing the clinical importance of fragmented QRS (fQRS) in many systemic diseases. In this study, we aimed to investigate the frequency and prognostic value of fQRS on electrocardiogram (ECG) in patients with acute ischemic stroke.

MATERIALS AND METHODS

We prospectively enrolled 241 patients with acute ischemic stroke between January 2018 and January 2020. ST depression and elevation, QRS duration, PR interval, RR interval, QTc interval, QTc dispersion (QTcd), T negativity, Q wave, and fQRS were evaluated on ECG. Brain computed tomography (CT) and diffusion magnetic resonance imaging (MRI) images were obtained in the acute period and the National Institute of Health Stroke Scale (NIHSS) score was calculated for each patient. Patients were followed up for a period of two years.

RESULTS

The 241 patients comprised 121 (50.2%) men and 120 (49.8%) women with a mean age of 67.52 ± 13.00 years. In Cox regression analysis, age, NIHSS, QTcd, and fQRS were found to be independent predictors of mortality (age, hazard ratio [HR]: 1.063, p < 0.001; NIHSS, HR: 1.116, p = 0.006; QTcd, HR: 1.029, p = 0.042; fQRS, HR: 2.048, p = 0.037). Two-year mortality was higher in patients with fQRS than in patients without fQRS (31% vs. 9%, p = 0.001).

CONCLUSIONS

The fQRS is associated with poor prognosis in patients with acute ischemic stroke.

Electrocardiographic differences in patients with true and pseudo-resistant hypertension

Cardiovascular disease is the leading cause of mortality in hypertensives, and patients with true resistant hypertension have an increased risk for premature cardiovascular events. Electrocardiography (ECG) has an essential role in the monitoring of hypertensive heart disease; however, little is known about the importance of ECG parameters in patients with resistant hypertension. We aimed to investigate whether fragmented QRS (fQRS) and frontal plane QRS-T angle, which are novel ECG parameters indicating myocardial damage, predict true resistant hypertension in patients with uncontrolled blood pressure. Four hundred six hypertensive patients with resistant hypertension were prospectively enrolled for the study. Patients were divided into two groups as 'true resistant' or 'pseudo-resistant' hypertensives and compared regarding the ECG parameters. While 73 (18%) patients had true resistant hypertension, 333 (82%) patients had pseudo-resistant hypertension. The frequency of fQRS (47.9% vs. 20.1%, p < 0.001) and average frontal plane QRS-T angle (93.0° ± 19.7° vs. 53.8° ± 10.2°, p < 0.001) were significantly higher in patients with true resistant hypertension compared to those with pseudo-resistant hypertension. Also, fQRS in anterior leads was significantly more frequent in patients with true resistant hypertension (57.1% vs. 23.8%, p < 0.001). Moreover, ROC curve analysis demonstrated that an increased frontal plane QRS-T angle > 90.75° predicted true resistant hypertension with a sensitivity 96% and specificity 61% (AUC:0.874, p < 0.001). Furthermore, multivariate analysis demonstrated that fQRS in anterior leads (OR: 1.251, 95% CI: 1.174-1.778, p = 0.002) and frontal plane QRS-T angle (OR: 1.388, 95% CI: 1.073-1.912, p < 0.001) were independent predictors of true resistant hypertension. In conclusion, fQRS and frontal plane QRS-T angle may be useful to predict true resistant hypertension in patients with uncontrolled blood pressure.

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).

Characteristics of Circadian Blood Pressure Pattern of Hypertensive Patients According to Localization of Fragmented QRS on Electrocardiography

INTRODUCTION

A narrow fragmented QRS complex (fQRS) indicates myocardial fibrosis and hypertensive cardiomyopathy in hypertensive patients. However, no study has investigated the importance of localization of fQRS on electrocardiography (ECG) in these subjects.

AIM

To investigate the association between circadian blood pressure (BP) pattern and localization of fQRS on ECG.

METHODS

A total of 291 hypertensive patients who had fQRS in anterior or inferior leads were included into the study. Patients were divided into two groups according to localization of fQRS in inferior or anterior leads. All patients underwent a 24-h ambulatory blood pressure monitoring for detailed evaluation of circadian BP pattern. The association between localization of fQRS and non-dipping was investigated.

RESULTS

Among study population, 182 (62.5%) patients had fQRS in inferior leads and 109 (37.5%) patients had fQRS in anterior leads. The frequency of patients with non-dipping BP pattern was significantly higher in patients with fQRS in anterior leads compared to patients with fQRS in inferior leads (47.7% vs 24.1%, p < 0.001). Moreover, the frequency of fQRS in anterior leads was significantly higher in non-dippers compared to dippers (64.6% vs. 24.1%, p < 0.001). Furthermore, in multivariate analysis, presence of fQRS in anterior leads was found to be an independent predictor of non-dipping BP pattern in hypertensive patients (OR: 1.748, 95% CI 1.362-2.446, p < 0.001).

CONCLUSIONS

Presence of fQRS in anterior leads is significantly associated with non-dipping BP pattern in hypertensive patients. Therefore, localization of fQRS on ECG may provide useful information regarding further risk assessment of hypertensive subjects.

Missing Link between Molecular Aspects of Ventricular Arrhythmias and QRS Complex Morphology in Left Ventricular Hypertrophy

The aim of this opinion paper is to point out the knowledge gap between evidence on the molecular level and clinical diagnostic possibilities in left ventricular hypertrophy (LVH) regarding the prediction of ventricular arrhythmias and monitoring the effect of therapy. LVH is defined as an increase in left ventricular size and is associated with increased occurrence of ventricular arrhythmia. Hypertrophic rebuilding of myocardium comprises interrelated processes on molecular, subcellular, cellular, tissue, and organ levels affecting electrogenesis, creating a substrate for triggering and maintaining arrhythmias. The knowledge of these processes serves as a basis for developing targeted therapy to prevent and treat arrhythmias. In the clinical practice, the method for recording electrical phenomena of the heart is electrocardiography. The recognized clinical electrocardiogram (ECG) predictors of ventricular arrhythmias are related to alterations in electrical impulse propagation, such as QRS complex duration, QT interval, early repolarization, late potentials, and fragmented QRS, and they are not specific for LVH. However, the simulation studies have shown that the QRS complex patterns documented in patients with LVH are also conditioned remarkably by the alterations in impulse propagation. These QRS complex patterns in LVH could be potentially recognized for predicting ventricular arrhythmia and for monitoring the effect of therapy.