Baseline fragmented QRS increases the risk of major arrhythmic events in hypertrophic cardiomyopathy: Systematic review and meta-analysis

Obstructive - Nonobstructive hypertrophic cardiomyopathy: differences and predictors

INTRODUCTION

Hypertrophic cardiomyopathy(HCM) is a genetic cardiomyopathy with a prevalence of 1/500 and causes adverse outcomes, usually due to left ventricular outflow tract obstruction.

AIM

In this study, we aimed to determine the possible differences and predictors of obstructive hypertrophic cardiomyopathy HCM (Obs-HCM) and nonobstructive HCM (Nonobs-HCM) by electrocardiographic (ECG) and echocardiographic (ECHO) evaluations with clinical, demographic, and biochemical characteristics.

METHODS

This study is a subgroup analysis of a multicentre, national, and observational 'LVH-TR study' that included 886 left ventricular hypertrophy(LVH) patients in 22 centres between February 2020 and August 2021. After excluding six patients with atrial fibrillation, pace rhythm, bundle branch blocks, and second, and third-degree atrioventricular(AV) block, 60 HCM patients were included, 23 of whom were obstructive, and 37 were nonobstructive.

RESULTS

Body surface area(BSA) (2.01 ± 0.17, 1.89 ± 0.19; p = .01), ST-segment depression (%82.6, %54.1; p = .02), QT and QTc durations (436.3 ± 58.3, 398.0 ± 65.5; p = .02/470.6 ± 58.7, 432.8 ± 74.7; p = .04), left ventricular mass index(LVMI) (176.4 ± 47.0, 152.7 ± 10.2; p = .004), and systolic anterior motion(SAM) rates (%82.6, %18.9; p < 0.001) were significantly higher in the obstructive HCM compared to nonobstructive HCM. Furthermore, the significance of ST-segment depression, QT duration, LVMI, and SAM continued in the univariate analyses to assess obstruction prediction (all p values < .05).

CONCLUSION

In multivariate and correlation analyses, ST segment depression (rho = 0.29), QT prolongation (rho = 0.34), and SAM (rho = 0.62) are found as predictors for obstruction (all p values < .05). Our study will guide future studies since it has detailed ECG and ECHO comparisons of Obs-HCM and Nonobs-HCM patients over 18 are made.

Fragmented QRS, a strong predictor of mortality and major arrhythmic events in patients with nonischemic cardiomyopathy: A systematic review and meta-analysis

Background and Aims

Fragmented QRS (fQRS), which is associated with rhythm disturbances, can predispose the heart to fatal ventricular arrhythmias. Recently, accumulating studies indicates that fQRS is associated with poor prognosis in various types of cardiomyopathies. Therefore, we assessed the association between fQRS with all-cause mortality and major arrhythmic events (MAEs) in patients with nonischemic cardiomyopathy, in this systematic review and meta-analysis study.

Methods

We performed a comprehensive search in databases of PubMed/Medline, EMBASE, and Web of Science from the beginning to December 31, 2022. Published observational studies (cohorts, case-control, or analytical cross-sectional studies) were included that report the prognostic value of fQRS in patients with different types of nonischemic cardiomyopathies for MAEs (sudden cardiac death, sudden cardiac arrest, sustained ventricular tachycardia [VT], ventricular fibrillation [VF], and appropriate shock) and all-cause mortality. We pooled risk ratios (RRs) through raw data and adjusted hazard ratios (aHRs) using "Comprehensive Meta-Analysis" software, Version 2.0.

Results

Nineteen cohort and three analytical cross-sectional studies were included in this meta-analysis involving a total of 4318 subjects with nonischemic cardiomyopathy (1279 with fQRS and 3039 without fQRS). FQRS was significantly associated with an increased risk of all-cause mortality in patients with nonischemic cardiomyopathy (pooled RR: 1.920; 95% confidence interval [CI]: 1.388-2.656, p < 0.0001/pooled HR: 1.729; 95% CI: 1.327-2.251, p < 0.0001). Also, the risk of developing MAEs in the presence of fQRS was significantly increased (pooled RR: 2.041; 95% CI: 1.644-2.533, p < 0.0001/pooled HR: 3.626; 95% CI: 2.119-6.204, p < 0.0001). In the subgroup analysis, the strongest association between fQRS presence and increased MAEs was observed in patients with hypertrophic cardiomyopathy (HCM) (pooled RR: 3.44; 95% CI: 2.07-5.71, p < 0.0001/pooled HR: 3.21; 95% CI: 2.04-5.06, p < 0.0001).

Conclusion

Fragmented QRS could be a prognostic marker for all-cause mortality and MAEs in patients with various types of nonischemic cardiomyopathies, particularly HCM.

Fragmented QRS on far-field intracardiac electrograms as a predictor of arrhythmic events

BACKGROUND

Studies suggest that fragmented QRS (fQRS) can predict arrhythmic events in various cardiac diseases. However, the association between fQRS recordings on intracardiac electrogram (EGM) and ventricular arrhythmic events remains unknown.

METHODS

We enrolled 51 patients (age, 62 ± 12 years; 40 men) with an implantable cardioverter-defibrillator (ICD) and structural heart disease and evaluated surface electrocardiogram (ECG) and EGM measurement of fQRS and the association between fQRS and arrhythmic events.

RESULTS

fQRS was detected on surface ECG and ICD-EGM in 12 (23.5%) and 15 (29.4%) patients, respectively. fQRS was detected more frequently on ICD-EGM in patients with fQRS on surface ECG than in patients without fQRS (7/12 [58.3%] vs 8/39 patients [20.5%], P = .01). Appropriate ICD therapies were documented in 16 patients. Among these patients, fQRS was detected more frequently on surface ECG and ICD-EGM in patients with appropriate ICD therapies (8/16, 50.0%; P = .001 and 11/16, 68.9%; P < .001). Nonsustained ventricular tachycardia was significantly more frequent in patients with appropriate ICD therapies (15/16, 93.8%; P = .04). Multiple logistic regression analysis showed that fQRS on ICD-EGM was a predictor of arrhythmic events (P = .03). Kaplan-Meier survival analysis revealed that ICD therapies were significantly more frequent among patients with fQRS on both surface ECG and ICD-EGM than among those without fQRS (66.7% vs 6.6%, P < .001).

CONCLUSION

The presence of fQRS on ICD-EGM can be a predictor of arrhythmic events in ICD patients. Surface ECG and ICD-EGM measurement may help predict ventricular arrhythmic events.

Deciphering hypertrophic cardiomyopathy with electrocardiography

The comprehensive assessment of patients with hypertrophic cardiomyopathy is a complex process, with each step concurrently focusing on confirmation of the diagnosis, differentiation between sarcomeric and non-sarcomeric disease (phenocopy), and prognostication. Novel modalities such as genetic testing and advanced imaging have allowed for substantial advancements in the understanding of this condition and facilitate patient management. However, their availability is at present not universal, and interpretation requires a high level of expertise. In this setting, electrocardiography, a fast and widely available method, still retains a significant role in everyday clinical assessment of this population. In our review, we follow a stepwise approach for the interpretation of each electrocardiographic segment, discussing clinical implications of electrocardiographic patterns in sarcomeric disease, their value in the differential diagnosis from phenocopies, and impact on patient management. Outlining the substantial amount of information to be obtained from a simple tracing, we exhibit how electrocardiography is likely to remain an integral diagnostic tool in the future as well.

Risk Prediction Models and Scores in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) has historically been linked with sudden cardiac death (SCD). Currently, it is well established that only a subset of patients is at the highest risk stratum for such a catastrophic event. Detection of patients belonging to this high-risk category can allow for timely defibrillator implantation, changing the natural history of HCM. Inversely, device implantation in patients deemed at low risk leads to an unnecessary burden of device complications with no apparent protective benefit. Previous studies have identified a series of markers, now considered established risk factors, with genetic testing and newer imaging allowing for the detection of novel, highly promising indices of increased risk for SCD. Despite the identification of a number of risk factors, there is noticeable discrepancy in the utility of such factors for risk stratification between the current American and European guidelines. We sought to systematically review the data available on these two approaches, presenting their rationale and respective predictive capacity, also discussing the potential of novel markers to augment the precision of currently used risk stratification models for SCD in HCM.

Clinical and molecular characterization of seven patients with Danon disease

Danon disease is an X-linked glycogen storage disease characterized by skeletal myopathy, cardiomyopathy and intellectual impairment. It is caused by a loss-of-function mutation in the lysosome-associated membrane protein-2 (LAMP2) gene. In the present study, exon and boarding intron analysis of 96 cardio disease-associated genes was performed in 770 patients with hypertrophic cardiomyopathy (HCM) using second-generation sequencing. Next, the identified mutations were confirmed in family members of the patients and 300 healthy controls. Detailed clinical, electrocardiographic (ECG) and echocardiographic findings were recorded. A pathogenic mutation in LAMP2 was identified in 7 patients who phenotypically presented with HCM. A total of four patients had a fragmented QRS complex (fQRS) on surface ECG. In addition, two patients presented with ventricular preexcitation with a short PR interval. Compared with the patients with protein kinase AMP-activated non-catalytic subunit γ2 syndrome and Fabry disease, the 7 patients with Danon disease presented at an earlier age, had a smaller left atrial size, a thinner maximal left ventricular wall thickness and a lower probability of pacemaker implantation. Compared with 12 sex- and age-matched patients with sarcomere-protein mutations, the 4 patients with Danon disease had a lower left ventricular outflow tract gradient and worse diastolic function. The present study provided a comprehensive comparison of different pathologies presenting with HCM and reported on features of early-onset Danon disease, including the characteristic preexcitation and fQRS on ECG. This may provide valuable information that may be utilized for the early diagnosis and treatment of patients with Danon disease. The present study was registered as a clinical trial with ClinicalTrials.gov (Sep. 2, 2016; registry no. NCT02888132).

Presence of fragmented QRS may be associated with complex ventricular arrhythmias in patients with type-2 diabetes mellitus

BACKGROUND

Ventricular arrhythmias (VAs) are frequent in diabetes mellitus (DM) patients. Myocardial fibrosis is one of the components of diabetic cardiomyopathy secondary to DM. Fragmented QRS (fQRS) on electrocardiography (ECG) has been shown to be a marker of myocardial fibrosis. In this study, we aimed to investigate the association between fQRS and complex VAs in patients with DM.

METHODS

Three hundred and thirty-six consecutive patients who were diagnosed with DM were included in the study. The control group consisted of 275 age- and sex-matched healthy individuals. ECG and transthoracic echocardiography were performed in all the patients. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. All the patients underwent 24-h Holter monitoring and VAs were classified using Lown's scoring system. Lown class ≥ 3 VAs were considered as complex VAs.

RESULTS

As compared to the healthy individuals, prevalence of fQRS (37.5% vs. 6.9%, p < .001) and complex VAs (14% vs. 0%, p < .001) were significantly higher in patients with DM. Furthermore, complex VAs (28.4% vs. 6.4%, p < .001) were significantly higher in DM patients with fQRS. In multiple logistic regression analysis, DM duration (OR: 1.510, 95% CI:1.343 to 1.698; p < .001) and presence of fQRS (OR: 3.262, 95% CI: 1.443 to 7.376; p = .004) were independent predictors for complex VAs.

CONCLUSIONS

The presence of fQRS may be associated with complex VAs in patients with DM. Therefore, fQRS may be used as a predictor of complex VAs and the risk of sudden death in patients with DM.

Fragmented QRS predicts reperfusion failure and in-hospital mortality in ST-Elevation myocardial infarction: a systematic review and meta-analysis

Objective: Recent studies have shown that fragmented QRS (fQRS) is associated with unfavourable outcomes in STEMI patients. However, there is controversy amongst studies. We performed a systematic review and meta-analysis to explore the effect of fQRS on reperfusion failure and in-hospital mortality among this population.Methods: We searched the databases of MEDLINE and EMBASE from inception to October 2018. Included studies were published cohort studies of STEMI patients that underwent primary percutaneous coronary intervention (pPCI) and thrombolysis. Data from each study were combined using the random-effects model.Results: Ten studies from January 2011 to October 2018 (2753 patients, 1075 patients with fQRS), were included. The fQRS was associated with higher risk of reperfusion failure in pPCI when defined by ST-segment resolution (OR = 3.08, 95% CI = 1.27-7.46, p-value = .013) but not when defined by TIMI flow grade (pooled OR = 1.45, 95% CI = 0.83-2.54, p-value = .192). In thrombolysis, fQRS was associated with higher risk of reperfusion failure when defined by both ST-segment resolution (pooled OR = 4.35, 95% CI = 1.80-10.49, p-value = .001) and TIMI flow grade (OR = 3.70, 95% CI = 2.10-6.53, p-value < .001). The fQRS was also associated with an increased risk of in-hospital mortality in both pPCI (pooled OR = 4.41, 95% CI = 1.60-12.16, p-value = .004) and thrombolysis (pooled OR = 2.38, 95% CI = 1.06-5.35, p-value = .036).Conclusions: Our meta-analysis demonstrated that fQRS in STEMI patients was associated with reperfusion failure as well as in-hospital mortality.

Fragmented QRS may be associated with complex ventricular arrhythmias in mitral valve prolapse

BACKGROUND

Although mitral valve prolapse (MVP) is a benign disease, several studies have indicated its association with ventricular arrhythmias (VAs). Some histopathological studies have pointed to left ventricular fibrosis as the underlying cause of arrhythmia in MVP patients. Fragmented QRS (fQRS) on electrocardiography (ECG) has been shown to be a marker of myocardial fibrosis. This study aimed to investigate the association between fQRS and complex VAs in patients with MVP.

METHODS

A total of 230 consecutive patients who were diagnosed with MVP were included in the study. The control group consisted of 302 healthy individuals matched according to age and sex. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. All patients underwent 24-hour Holter monitoring and VAs were classified using Lown's scoring system. Lown class ≥3 VAs were considered as complex VAs.

RESULTS

As compared to the healthy individuals, prevalence of fQRS (40% vs. 9.6%, P<0.001) and complex VAs (18.7% vs. 0%, P<0.001) were significantly higher in patients with MVP. Furthermore, complex VAs (35.9% vs. 7.2%, P=0.001) were significantly higher in MVP patients with fQRS. In multiple logistic regression analysis, the presence of bileaflet prolapse (OR: 2.567, 95%CI: 1.434 to 4.367; P=0.002) and presence of fQRS (OR: 3.021, 95%CI: 1.556 to 6.232; P<0.001) were independent predictors for complex VAs.

CONCLUSIONS

The presence of fQRS may be associated with complex VAs in patients with MVP. Therefore, fQRS may be used in risk stratification of complex VAs in patients with MVP.

New Appearance of Fragmented QRS as a Predictor of Ventricular Arrhythmic Events in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Multiple spikes in the QRS complex (fragmented QRS [fQRS]) on 12-lead electrocardiography have been associated with ventricular arrhythmic events (VAEs) in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to assess the association between new appearances of fQRS and cardiac events in patients with HCM.Methods and Results:The association between baseline fQRS and cardiac events, namely VAEs, heart failure-related hospitalization, and all-cause death, was evaluated retrospectively in 146 HCM patients (46 patients with fQRS, 100 without fQRS). The median follow-up was 5.3 years. Cardiac events occurred in 29 patients with baseline fQRS and 32 patients without baseline fQRS (63% vs. 32%; P<0.001). VAEs occurred in a significantly larger percentage of patients with than without baseline fQRS (54% vs. 23%, respectively; P<0.001). Of the 100 patients without baseline fQRS, 33 had a new appearance of fQRS during the 4.6-year follow-up, whereas 67 did not. VAEs occurred more frequently in the 33 patients with the appearance of fQRS than in those without (42% vs. 13%, respectively; P=0.001). Multivariable analysis showed that the new appearance of fQRS documented before VAEs was associated with VAEs (hazard ratio 4.29, 95% confidence interval 1.81-10.2; P=0.001).

CONCLUSIONS

The new appearance of fQRS was associated with an increased risk of VAEs in HCM patients.

The presence of fragmented QRS may predict the recurrence of nonvalvular atrial fibrillation after successful electrical cardioversion

OBJECTIVE

Atrial fibrillation (AF), the most common cardiac rhythm disorder, affects approximately 2% of the general population and is associated with increased risk of stroke and mortality as well as reduced exercise capacity and quality of life. After restoring normal sinus rhythm, a portion of these patients develops recurrent AF despite optimal medical treatment. In this study, we aimed to assess the relationship between the presence of fragmented QRS (fQRS) and AF recurrence following successful electrical cardioversion (ECV).

MATERIAL AND METHODS

A total of 306 patients with nonvalvular persistent AF achieving restoration of the sinus rhythm after successful ECV were included in this study. After ECV, patients were monitored at least 6 months for recurrence. The patients were divided into two groups according to the presence of fQRS and compared for AF recurrence during follow-up.

RESULTS

Patients were followed up for a mean time of 220 ± 113 days. AF recurred in 119 patients, corresponding to a recurrence rate of 38.8%. AF recurrence was found to be significantly increased in patients with fQRS as compared to those without fQRS (76.4% vs. 23.5%, p < .001). Furthermore, the presence of fQRS was higher in patients with recurrent AF as compared to others (57.1% vs. 11.2%, p < .001). In multiple regression analyses, the presence of fQRS was one of the independent predictors of AF recurrence (hazard ratio: 9.670, 95% CI: 4.714-19.837, p < .001).

CONCLUSION

The presence of fQRS may be associated with the recurrence of AF after successful ECV in persistent nonvalvular AF patients.

The relationship between galectin-3 levels and fragmented QRS (fQRS) in patients with heart failure with reduced left ventricular ejection fraction

BACKGROUND

Fragmented QRS (fQRS) complex is an electrocardiographic pattern which reflects myocardial scarring. We aimed to investigate the relationship between the presence of fragmented QRS (fQRS) on electrocardiogram (ECG) and plasma galectin-3 levels in patients with heart failure (HF) and severely decreased left ventricular ejection fraction (LVEF ≤ 35%).

METHODS

We prospectively enrolled 125 symptomatic HF patients (NYHA class II-III) with severely reduced LVEF (≤35%). fQRS was identified in ECG. Galectin-3 and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured. Patients were divided into two groups based on the presence (n = 40) or absence (n = 85) of a fQRS on ECG.

RESULTS

Majority of patients were male (87.70%), and mean age was 65.1 ± 11.6. Galectin-3 and NT-proBNP levels were found to be significantly higher in the fQRS (+) group compared with the fQRS (-) group (NT-proBNP 5,362 ± 701 pg/ml vs. 4,452 ± 698 pg/ml; p < 0.001, galectin-3 607 ± 89.8 pg/ml vs. 509.4 ± 63.5 pg/ml; p < 0.001). Multivariate analyses revealed galectin-3 and NT-proBNP levels are the presence of fQRS on ECG (p < 0.001 and p < 0.001, respectively). The area under the curve using the galectin-3 level for fQRS was 0.819.

CONCLUSIONS

fQRS and serum galectin-3 levels are associated with myocardial fibrosis and are associated with poor prognosis in heart failure. In our study, a positive correlation was found between serum galectin-3 levels and fQRS on ECG.

Baseline fragmented QRS is associated with increased all-cause mortality in heart failure with reduced ejection fraction: A systematic review and meta-analysis

BACKGROUND

Recent studies suggested that fragmented (fQRS) is associated with poor clinical outcomes in heart failure with reduced ejection fraction (HFrEF) patients. However, no systematic review or meta-analysis has been done. We conducted a systematic review and meta-analysis to assess the association between baseline fQRS and all-cause mortality in HFrEF.

METHODS

We comprehensively reviewed the databases of MEDLINE and EMBASE from inception to February 2018. Published studies of HFrEF that reported fQRS and outcome of all-cause mortality and major arrhythmic event (sudden cardiac death, sudden cardiac arrest, ventricular fibrillation, or sustained ventricular tachycardia) were included. Data were integrated using the random-effects, generic inverse-variance method of DerSimonian and Laird.

RESULTS

Ten studies from 2010 to 2017 were included. Baseline fQRS was associated with increased all-cause mortality (risk ratio [RR] 1.63, 95% confidence interval [CI] 1.22-2.19, p < 0.0001, I²  = 73%) as well as major arrhythmic events (RR = 1.74, 95% CI 1.09-2.80, I²  = 89%). Baseline fQRS increased all-cause mortality in both Asian and Caucasian cohorts (RR = 2.17 with 95% CI 1.33-3.55 and RR = 1.45 with 95% CI 1.05-1.99, respectively) as well as increased major arrhythmic events in Asian cohort (RR = 1.50, 95% CI 1.05-2.13). Baseline fQRS also increased all-cause mortality in patients who had not received implantable cardioverter-defibrillator, significantly more than in patients who had received implantable cardioverter-defibrillator (RR = 2.46 with 95% CI 1.56-3.89 and 1.36 with 95% CI 1.08-1.71, respectively).

CONCLUSION

Baseline fQRS is associated with increased all-cause mortality up to 1.63-fold in HFrEF patients. Fragmented QRS could be a predictor of clinical outcome in patients with HFrEF.

Baseline fragmented QRS increases the risk of major arrhythmic events in hypertrophic cardiomyopathy: Systematic review and meta-analysis

BACKGROUND

Fragmented QRS reflects disturbances in the myocardium predisposing the heart to ventricular tachyarrhythmias. Recent studies suggest that fragmented QRS (fQRS) is associated with worse major arrhythmic events in hypertrophic cardiomyopathy (HCM). However, a systematic review and meta-analysis of the literature has not been done. We assessed the association between fQRS and major arrhythmic events in hypertrophic cardiomyopathy by a systematic review of the literature and a meta-analysis.

METHODS

We comprehensively searched the databases of MEDLINE and EMBASE from inception to May 2017. Included studies were published prospective or retrospective cohort studies that compared major arrhythmic events (sustained ventricular tachycardia, sudden cardiac arrest, or sudden cardiac death) in HCM with fQRS versus non-fQRS. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals.

RESULTS

Five studies from January 2013 to May 2017 were included in this meta-analysis involving 673 subjects with HCM (205 fQRS and 468 non-fQRS). Fragmented QRS was associated with major arrhythmic events (pooled risk ratio = 7.29, 95% confidence interval: 4.00-13.29, p < .01, I²  = 0%).

CONCLUSION

Baseline fQRS increased major arrhythmic events up to sevenfold. Our study suggests that fQRS could be an important tool for risk assessment in patients with HCM.