QRS fragmentation is associated with increased risk of ventricular arrhythmias in high-risk patients; Data from the SMASH 1 Study.

INTRODUCTION: QRS fragmentation (fQRS), defined as the presence of additional spikes within the QRS complex, has been associated with myocardial conduction abnormalities and arrhythmogenicity. OBJECTIVE: We aimed to assess whether fQRS is associated with incident ventricular arrhythmias (VA) in high-risk patients treated with implantable cardioverter-defibrillator (ICD) for primary and secondary prevention. METHODS: In a prospective observational multicenter study, we included 495 patients treated with ICD. fQRS was analyzed according to previously validated criteria, by two physicians blinded for outcome data. Incident VA were obtained from ICD recordings. RESULTS: ECG recordings interpretable for fQRS were available in 459 patients (93%), aged 66 ± 12 years with left ventricular ejection fraction 40% ± 13%. fQRS was present in 52 patients (11%) with comparable baseline characteristics to patients without fQRS, except higher age, higher prevalence of coronary artery disease (CAD), lower prevalence of cardiomyopathy, and more frequently a secondary prevention ICD indication. Among patients with native QRS, those with fQRS had similar QRS duration and axis to those without fQRS. During 3.1 ± 0.7 years follow-up, 126 patients (28%) had ≥1 VA . fQRS was associated with increased risk of VA (HR 3.41 [95% CI 2.27-5.13], p < .001), which persisted after adjusting for age, gender, sex, BMI, CAD, heart failure, renal function, ICD indication, QRS duration, QRS axis, Q waves, and bundle branch block. fQRS was more strongly associated with VA in patients with a primary (HR 6.05 [95% CI 3.16-11.60]) versus secondary (HR 2.39 [95% CI 1.41-4.04]) ICD indication (p-for-interaction = .047). CONCLUSIONS: fQRS is associated with threefold increased risk of VA in high-risk patients, independent of established risk factors.

Subtle QRS changes are associated with reduced ejection fraction, diastolic dysfunction, and heart failure development and therapy responsiveness: Applications for artificial intelligence to ECG.

BACKGROUND: Since the last century, the electrocardiogram (ECG) remains the non-invasive test, that is, most easily accessible, feasible, and inexpensive for cardiology assessment. In past years, many novel ECG indexes and patterns have been published that allow for a more advanced evaluation of what is currently being done, especially based on subtle QRS changes and patterns. OBJECTIVE: The objective of the study was to provide an update on the evidence and clinical applications of these ECG subtle QRS changes and patterns associated with heart disease. METHODS: Through the literature review, we will highlight the subtle QRS changes and patterns associated with heart disease, mainly focusing on QRS duration, voltage, morphology, axis, and QT interval. RESULTS: Small increases in QRS duration are associated with a reduction in left ventricular ejection fraction (EF), increased cardiac chamber dimensions, and risk for incident heart failure (HF). Moreover, fragmentation of the QRS complex is associated with myocardial fibrosis and is a substrate for developing arrhythmic events. Besides, low amplitude QRS voltage is associated with congestive HF, and an increase in the voltage of the QRS complexes is associated with the effectiveness of diuresis treatment. Furthermore, small increases in QT interval are associated with diastolic dysfunction due to impaired sarcoplasmic reticulum calcium handling as occurs in myocardial ischemia, hypertension, or diabetes. On the other hand, in patients with left ventricular dysfunction, the QRS area is associated with clinical and echocardiographic response to cardiac resynchronization therapy regardless of the type of bundle branch block. In addition, subtle ECG changes and patterns in the left bundle branch block are associated with concomitant right ventricular dilation, mostly based on the QRS axis and voltage. Notwithstanding, to identify these subtle changes in QRS require exact manual measurements that can take time. In this regard, applying artificial intelligence (AI) to the ECG can make a quicker and more complete assessment, as well as provide a low cost when applied to large populations. CONCLUSION: We provided an update on the evidence and clinical applications of these subtle QRS changes and patterns associated with diastolic dysfunction, reduced EF, and HF development and therapy responsiveness, as well as their applications for AI to ECG.

Clinical utility of 12-lead electrocardiogram in evaluating heart disease in patients with muscular dystrophy: Assessment of left ventricular hypertrophy, conduction disease, and cardiomyopathy.

INTRODUCTION: Heart disease remains a leading cause of mortality in patients with muscular dystrophy (MD), and cardiac assessment by standard imaging modalities is challenging due to the prominence of physical limitations. METHODS: In this prospective cohort study of 169 MD patients and 34 negative control patients, we demonstrate the clinical utility of a 12-lead electrocardiogram (ECG) as an effective modality for the assessment of cardiac status in patients with MD. We assessed the utility of conventional criteria for electrocardiogram-indicated left ventricular hypertrophy (ECG-LVH) as well as ECG morphologies. RESULTS: Cornell voltage, Cornell voltage-duration, Sokolow-Lyon voltage, and Romhilt-Estes point score criteria demonstrated low sensitivity and minimal positive predictive value for ECG-LVH when compared with cardiac imaging. Patients with LBBB had a high probability of a cardiomyopathy (relative risk [RR], 2.75; 95% confidence interval [CI], 2.14-3.53; p < .001), and patients with QRS fragmentation (fQRS) had a high probability of a cardiomyopathy (RR, 1.76; 95% CI, 1.20-2.59; p = .004), requiring cardiac medication and device intervention. We found that an R/S ratio >1 in V1 and V2 is highly specific (specificity, 0.89; negative predictive value [NPV], 0.89 and specificity, 0.82; NPV, 0.89, respectively) for patients with dystrophinopathies compared with other types of MD. CONCLUSION: The identification of LBBB and fQRS was linked to cardiomyopathy in patients with MD, while ECG-LVH was of limited utility. Importantly, these findings can be applied to effectively screen a broad cohort of MD patients for structural heart disease and prompt further evaluation and therapeutic intervention.

Prevalence and significance of fragmented QRS complex in lead V1 on the surface electrocardiogram of healthy athletes.

AIMS: Limited data exist concerning fragmented QRS complexes (fQRSs) on the surface electrocardiogram (ECG) of apparently healthy athletes. We aimed to study the prevalence and significance of fQRS in lead V1 (fQRSV1), representing right ventricular (RV) activation, regarding training-induced RV morphological remodelling. METHODS AND RESULTS: Between January 2017 and August 2019, 434 consecutive non-sedentary subjects underwent preparticipation cardiovascular screening, including a 12-lead ECG. Three hundred and ninety-three apparently healthy subjects were included, 119 of them were athletes (defined as performing ≥8 h/week for the last 6 months) and 274 were non-athletes. All athletes underwent two-dimensional transthoracic echocardiography. Fragmented QRS complex in lead V1 pattern was defined as a narrow (<120 ms) and quadriphasic QRS complex in lead V1. Fragmented QRS complex in lead V1 was more frequent in athletes compared with non-athletes (22% vs. 5.1%, P < 0.001) and was independently associated with the athlete status [adjusted odds ratio (aOR) = 4.693, 95% confidence interval (95% CI) 2.299-9.583; P < 0.001], the endurance category (aOR = 2.522, 95% CI 1.176-5.408; P = 0.017), and age (aOR = 0.962, 95% CI 0.934-0.989; P = 0.007) in multivariate analysis. In the subgroup of athletes, fQRSV1 was independently associated with mean RV outflow tract diameter (aOR = 1.458, 95% CI 1.105-1.923; P = 0.008) and age (aOR = 0.941, 95% CI 0.894-0.989; P = 0.017) in multivariate analysis. CONCLUSION: Fragmented QRS complex in lead V1 is a newly described, frequent, ECG pattern in young and apparently healthy athletes and is associated with training-induced RV remodelling.

Relationship Between Fragmented QRS Complexes and Cardiac Status in Duchenne Muscular Dystrophy: Multimodal Validation Using Echocardiography, Magnetic Resonance Imaging, and Holter Monitoring.

The presence of fragmented QRS is a known marker of heterogeneous ventricular activation around the myocardial scar area. We validated whether fragmented QRS shows any association with ventricular dysfunction, fibrosis, or ventricular arrhythmias in patients with Duchenne muscular dystrophy (DMD). Thirty-seven patients with DMD were evaluated using electrocardiography (ECG), echocardiography, cardiac magnetic resonance, and 24-h Holter monitoring. Associations between fragmented QRS and ventricular dysfunction, fibrosis, or ventricular arrhythmia were investigated. Fragmented QRS complexes were present in 31 of 37 (83.7%) patients, and they were associated with a significantly lower left ventricular ejection fraction along with an increased left ventricular Tei index as evaluated by echocardiography, and more frequent ventricular arrhythmia as indicated using 24-hour Holter monitoring compared with patients without fragmented QRS. The number of leads with fragmented QRS correlated negatively with left ventricular ejection fraction both using echocardiography (r = -0.616) and CMR (r = -0.516). Further, the number of leads with fragmented QRS showed a significant correlation with several other echocardiographic measurements (mitral Em and Sm, and left ventricular Tei index), and 2-dimensional speckle-tracking echocardiography derived global left ventricular longitudinal strain. The frequency of ventricular arrhythmia observed using Holter monitoring showed a significant positive correlation with the frequency of fragmented QRS on ECG (r = 0.674). There was a positive trend of correlation between fragmented QRS and the amount of myocardial fibrosis as assessed by late gadolinium enhancement using CMR, but the statistical significance of the relationship was low (r = 0.433, p = 0.056). Fragmentation of QRS complexes is associated with degrees of left ventricular dysfunction, fibrosis, and ventricular arrhythmias in patients with DMD.

Fragmentation of the paced QRS complex: a marker of antitachycardia pacing effectiveness among ICD patients.

INTRODUCTION: The presence of notches in the paced QRS complex (P-QRS) from the right ventricular apex (RVA) reflects delays in the activation of the left ventricle and may therefore be associated with longer times of stimulus conduction. Our objective was to determine prospectively the relationship between the duration of a notch ≥0.1 mV in the P-QRS (DN) and the effectiveness of antitachycardia pacing (ATP). METHODS AND RESULTS: We followed 286 implantable cardioverter-defibrillator (ICD) patients with left ventricular dysfunction (pacing site: RVA) for 41 ± 27 months. ICD programming was standardized. P-QRS (100 bpm) was obtained at implant (50 mm/s). A total of 955 monomorphic ventricular tachycardias (VTs) with a cycle length of 335 ± 32 milliseconds occurred consecutively in 108 patients. ATP was successful in 84% of VTs. DN correlated with the probability of ineffective ATP (C = 0.67; P < 0.001), the cutoff point with the best sensitivity and specificity being 50 milliseconds. The adjusted mean ATP effectiveness per patient was 76% (95% CI: 72-85). Patients with a DN ≥ 50 milliseconds had a lower ATP efficiency: 67% (56-77) versus 92% (87-97) and a higher proportion of VTs terminated with shocks (SH): 31% (21-42) versus 8% (2-14); P < 0.001 for both. Although the occurrence of VT was similar (41% vs. 40%), the incidence of VT-related SH was higher in patients with a DN ≥ 50 (25% vs. 14%; P = 0.01) in the overall study population (n = 286). CONCLUSIONS: When ATP is applied to the RVA, a DN ≥ 50 milliseconds is associated with a lower ATP effectiveness and a higher risk of SH due to VT.

The pathophysiologic aspects and clinical implications of electrocardiographic parameters of ventricular conduction delay in repaired tetralogy of Fallot.

The 12-lead surface electrocardiogram is a valuable and feasible clinical tool in the management of patients following tetralogy of Fallot (TOF) repair. The importance of QRS duration in TOF patients has long been acknowledged. A prolonged QRS complex has been associated with increased risk for subsequent life-threatening ventricular arrhythmia and sudden cardiac death. Our current ability to risk-stratify TOF patients for malignant arrhythmogenic events primarily on the basis of QRS duration is rather limited. Nevertheless, increasing evidence suggests that QRS morphology and duration may be useful as surrogate markers of infundibular and regional right ventricular myocardial disease. The aim of this review is to provide a critical appraisal of the clinical implications of established and new electrocardiographic markers of ventricular conduction delay in TOF patients following surgical correction with a particular focus on QRS duration, lengthening, and fragmentation. In addition, the pathophysiological background of these parameters is addressed.

Physiological Changes in QRS Fragmentation in Athletes and Nonathletes without Cardiac Disease.

Background/Objectives: QRS fragmentation has not been linked with increased mortality in individuals without known cardiac disease. We aimed to investigate the physiological determinants of QRS fragmentation in individuals without cardiac disease. Methods: Study participants were 163 (54 athletes, 109 nonathletes) asymptomatic individuals with QRS fragmentation but without cardiac disease. QRS fragmentation was assessed in the supine position after deep inspiration or standing up and during exercise. The changes in QRS fragmentation were evaluated over a median follow-up period of 2.3 (0.8-4.9) years. Results: The most common lead with QRS fragmentation was III (63.0% in athletes, 61.5% in nonathletes), immediately followed by V1 (50.0%) and aVF (42.6%) in athletes and aVF (55.0%) in nonathletes. QRS fragmentation in V1 was more frequent in athletes compared to nonathletes (p < 0.001). Among athletes, the presence of QRS fragmentation in V1 could be independently predicted by increased RVOTproxi (right ventricular outflow tract proximal diameter indexed to body surface area) (p < 0.001). Among individuals with QRS fragmentation in V1, deep inspiration resulted in disappearance of QRS fragmentation more frequently in nonathletes compared to athletes (100% vs. 20%, p = 0.003). Deep inspiration resulted in disappearance of QRS fragmentation in aVF (p < 0.001). The presence of QRS fragmentation in II or aVF was associated with increased body mass index (BMI) (p = 0.003). Among athletes without QRS fragmentation in V1 at baseline, the appearance of QRS fragmentation in V1 at the end of follow-up was associated with greater training age (p = 0.034). Among individuals with QRS fragmentation in aVF at baseline, the disappearance of QRS fragmentation in aVF at the end of follow-up was associated with greater reduction in BMI (p = 0.008). Conclusions: The characteristic feature of QRS fragmentation in athletes was the presence of QRS fragmentation in V1, which was associated with RVOTproxi. The persistence of QRS fragmentation in V1 after deep inspiration could serve as a specific marker of exercise-training-related cardiac adaptation. The presence of QRS fragmentation in the leads of the frontal plane was influenced by BMI and respiration phase.

The Fragmented QRS Complex in Lead V1: Time for an Update of the Athlete's ECG?

Differentiating between ECG patterns related to athletes' heart remodeling and pathological findings is a challenge in sports cardiology. As the significance of fragmented complex in athletes remains uncertain, this study aimed to assess the presence of fragmented QRS in lead V1 (fQRSV1) among young athletes and its association with heart adaptations and arrhythmias. Young athletes referred for annual pre-participation screening receiving a maximal exercise testing and transthoracic echocardiography from January 2015 to March 2021 were included. The study included 684 young athletes. The prevalence of fQRSV1 was 33%. Subjects with fQRSV1 had higher exercise capacity and indexes of right ventricular function and remodeling. Among highly trained athletes, the fQRSV1 group demonstrated also increased left ventricular wall thickness. No significant association existed between fQRSV1 and exercise-induced arrhythmias, even in highly trained athletes. The high prevalence of fQRSV1 in young athletes is associated with training-induced heart adaptations but not exercise-induced ventricular arrhythmias.

Fragmented QRS complex predicts the arrhythmic events in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Fragmented QRS (frQRS) complex, with various morphology, has been recently described as a diagnostic criterion of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). However, there are little data regarding the prognostic role of frQRS in these patients. Therefore, we aimed to investigate the association of frQRS with arrhythmic events in patients with ARVC/D. METHODS: Seventy-eight patients (51 men, 65.4%; mean age: 31.25 ± 11.5 years) with the diagnosis of ARVC/D according to 2010 modified Task Force Criteria were analyzed retrospectively. Baseline ECG evaluation revealed frQRS complex in 46 patients (59%). Eleven patients with complete/incomplete right bundle branch block were excluded from the study. The phenomenon of frQRS was defined as deflections at the beginning of the QRS complex, on top of the R-wave, or in the nadir of the S-wave similar to the definition in CAD in either one right precordial lead or in more than one lead including all standard ECG leads. RESULTS: During 38 ± 14 months follow-up period, 3 patients (3.8%) died suddenly, 36 patients (46.1%) experienced arrhythmic events (32 ventricular tachycardias [VTs] and 4 ventricular fibrillation [VF], 30 in the ICD group). The frQRS was significantly associated with arrhythmic events (P < 0.001). Also, the number of ECG leads with frQRS complex was higher in patients with arrhythmic events (5.08 ± 2.5 vs 1.14 ± 1.7, P < 0.001, respectively). CONCLUSION: The frQRS complex on standard 12-lead ECG predicts fatal and nonfatal arrhythmic events in patients with ARVC/D. Therefore, large scale and prospective studies are needed to confirm those findings.

QRS fragmentation versus QRS prolongation in predicting right ventricular enlargement and dysfunction in children and adults with repaired Tetralogy of Fallot.

Patients with repaired Tetralogy of Fallot (rTOF) have risks of late life-threatening sequelae, including right ventricular (RV) dilation and failure, arrhythmias, and sudden death. QRS prolongation is a well-known ECG predictor of these outcomes but has poor sensitivity for mortality. Growing evidence demonstrates QRS fragmentation (fQRS) as a better prognostic marker for mortality in adults with rTOF, though the two markers have not been directly compared as correlates for CMR abnormalities. Additionally, fQRS has never been studied in pediatric TOF. This single institution retrospectively reviewed 138 CMRs in rTOF patients (median age 21.7 years) who had a corresponding 12-lead ECG within 1 year. fQRS was defined as ≥3 R-waves/notches in the R/S complex (>2 in right bundle branch block) in ≥2 contiguous leads. QRS prolongation was defined as QRS ≥160 ms. Nearly half (46%) the sample had fQRS (42.1% of pediatric subgroup), and 26% had QRS prolongation. Both markers were significantly associated with reduced RV ejection fraction (EF%) (p < 0.01) and larger RV end-diastolic volumes (p < 0.01). QRS prolongation alone predicted lower LV EF% (p = 0.02). Regression analyses showed both QRS prolongation (p < 0.01) and fQRS (p < 0.01) independently associated with reduced RV EF%; QRS prolongation alone predicted RV dilation (p < 0.01). We concluded that both QRS prolongation and fQRS are equivalent as significant markers of RV dysfunction in rTOF patients. QRS prolongation may be a better surrogate for RV dilation specifically. fQRS was frequently seen in children with rTOF and was significantly associated with similar late structural sequelae.

Early Diagnosis of Acute Myocarditis in the ED: Proposal of a New ECG-Based Protocol.

The diagnosis of acute myocarditis (AM) is based on a multi-parametric assessment including clinical presentation, ECG, imaging and biomarkers. Fragmented QRS (fQRS) might be an additional diagnostic sign in patients with proven AM. The main objective of this study was to assess the diagnostic yield of fQRS in patients with suspected AM presenting to the emergency department (ED). Patients admitted between January 2016 and March 2021 with a proven diagnosis of AM, according to clinical, cardiac magnetic resonance (CMR) and/or histologic criteria, were included in the analysis. In total, 51 patients were analyzed (41 men, 78%), with a median age of 36 (29-45) years. Thirty-three (65%) patients had prodromal flu-like symptoms. Patients presented to the ED mostly complaining of chest pain (68%) and palpitations (21%). Seven (14%) patients experienced cardiac arrest, one of whom died. At presentation, 40 patients (78%) displayed fQRS, and 10 (20%) presented ventricular arrhythmias. All the surviving patients underwent CMR and displayed late gadolinium enhancement (LGE). ECG leads showed that fQRS matched the LGE distribution in 38 patients (95%). The presence of fQRS is a simple clinical bedside tool to support the initial suspect of AM in the emergency department and to guide the most appropriate clinical workup.

Fragmentation of Ventricular Extrasystoles: A Potential New Electrocardiographic Window to Uncover Patients at Risk.

Fragmented QRS (fQRS) is a marker of conduction block due to myocardial scar that presents in electrocardiography (ECG) as an additional one or more R wave (R') or notching in the S wave nadir in contiguous leads. However, fQRS description on premature ventricular contractions (PVCs) has not been previously described. We describe a case of a 67-year-old male with a past medical history of prediabetes, hypertension and coronary artery disease who presented after an ophthalmic procedure with asymptomatic PVCs and episodes of bigeminy. Initial ECG showed an isolated fQRS in V2. However, during PVCs significant extrasystoles fragmentation was seen in other coronary territories. Upon reviewing his most recent cardiac catheterization, it showed a 40% ostial and 70% distal left anterior descending stenosis with a mid-segment patent stent, 95% first diagonal stenosis and totally occluded proximal right coronary artery. Identification of diffuse fQRS known to be associated with myocardial scar, sustained arrhythmic events and sudden cardiac death, particularly when seen in the inferior leads, became extremely relevant in our patient. We noted that ejection fraction reduction from 52% to 34% on his last coronary intervention was crucial to decide if an implantable cardioverter-defibrillator would be needed. PVC fragmentation might be a new ECG marker that could uncover both scar and arrhythmia potential in patients at risk of adverse cardiac events.

The ECG in sarcoidosis - a marker of cardiac involvement? Current evidence and clinical implications.

Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by noncaseating granulomas. Cardiac involvement is often limiting patients' prognosis. Cardiac sarcoidosis can manifest with variant cardiac arrhythmias, of which atrioventricular (AV)-block-related bradycardia and ventricular tachycardias are the most common. Although cardiac sarcoidosis remains a histopathological diagnosis, the significance of imaging modalities, especially cardiac magnetic resonance imaging is increasing rapidly but mainly remains reserved for patients with a high suspicion due to a previous arrhythmia or unknown cardiomyopathy. Thus, there is a need for screening in daily clinical practice so that possible characteristic electrocardiographic (ECG) findings may guide the way to detect the disease. We therefore evaluated the ECG as a potential tool for screening of cardiac sarcoidosis and present different electrophysiological manifestations of cardiac sarcoidosis based on a literature review. The ECG is a valuable tool for screening of cardiac involvement in patients with sarcoidosis. Several parameters have been shown to be associated with cardiac involvement in sarcoidosis such as higher-degree AV-block, QRS complex fragmentation and widening, as well as certain T wave abnormalities that may indicate cardiac involvement, of which the latter two are most promising and specific. However, prospective studies examining a large number of trials are desirable.

QRS fragmentation as a possible electrocardiographic diagnostic marker in patients with acute myocarditis: preliminary histopathological validation.

AIMS: We aim to assess the reproducibility of QRS fragmentation (fQRS) on a multi-centre dataset of patients with acute myocarditis (AM), including a histopathological validation in a subgroup with biopsy-proven disease. Electrocardiogram (ECG) in patients with myocarditis is usually considered aspecific. ST changes and conduction anomalies have been commonly reported so far. We have previously described fQRS in patients with AM. METHODS AND RESULTS: Patients admitted between 2008 and 2019 in two centres with a diagnosis of AM were included. Standard ECG, echocardiography, and cardiac magnetic resonance (CMR) findings were recorded at baseline and at follow-up (FU). Eighty patients were analysed, 66 men (82%), with median age of 34 (26-43) years. Twenty-two patients had biopsy-proven AM. At presentation, 61 patients (76%) displayed fQRS. Median ejection fraction (EF) was 55% (43-60). Seventy-two patients (90%) underwent CMR and displayed late gadolinium enhancement (LGE). ECG leads showed that fQRS correlated with distribution of LGE. In patients with positive biopsy, fQRS was present in 18 (81%). Median FU was 419 days (224-956). Complete FU was available for 64 patients (80%), and 33 patients (52%) displayed persistence of fQRS. Median EF was 60% (57-64). Eleven patients underwent a repeated biopsy at FU, eight of whom had persistent inflammation and fQRS. Fifteen patients (23%) had ventricular tachycardia, 14 of whom still showed fQRS. CONCLUSIONS: In this cohort fQRS was confirmed as an additional useful ECG sign. Persistence of fQRS was associated with ongoing inflammation and with a poorer outcome in terms of ventricular function and occurrence of arrhythmias.

Role of QRS fragmentation in 12-lead surface ECG in prediction of isolated epicardial coronary artery ectasia and its anatomical distribution in patients without acute coronary syndromes.

BACKGROUND: Coronary artery ectasia (CAE) is a form of abnormal coronary artery lumen dilatation associated with epicardial flow disturbances and microvascular dysfunction. QRS complex fragmentation (fQRS) in surface ECG is caused by abnormal depolarization due to myocardial ischemia and scarring. It has been proved in different studies to be positively correlated with adverse cardiac events. This study aimed to assess the role of fQRS as a non-invasive predictor of CAE and its anatomical distribution. A total of 100 patients referred for elective coronary angiography were included and divided into 2 groups: 50 patients with isolated CAE (group A) and 50 patients with angiographically normal coronaries (group B, control group). Both groups were compared regarding clinical, echocardiographic, and ECG characteristics. RESULTS: Univariate analysis showed a significant correlation between male sex, smoking, diabetes mellitus, increased systolic blood pressure, fQRS, echocardiographic evidence of diastolic dysfunction, and CAE (P values of 0.005, 0.002, 0.016, 0.027, 0.0001, and 0.04, respectively). Multivariate regression analysis showed that fQRS is the most important independent predictor for the presence of CAE (P < 0.00001) with sensitivity 94%, specificity 88%, PPV 88.7%, and NPV 93.6%. We also found a significant correlation between fQRS distribution in surface ECG and anatomical distribution of CAE [increased territories with multivessel affection (P = 0.00001), anterior leads with LAD affection (P = 0.00001), lateral and inferior leads with LCX affection (P = 0.003 and 0.04, respectively), inferior leads with RCA affection (P = 0.00001)]. CONCLUSION: fQRS in surface ECG can potentially be used as an effective non-invasive method to predict isolated CAE and its anatomical distribution.

Prognostic significance of QRS fragmentation and correlation with infarct size in patients with anterior ST-segment elevation myocardial infarction treated with percutaneous coronary intervention: Insights from the INFUSE-AMI trial.

BACKGROUND: QRS fragmentation (fQRS) is believed to reflect myocardial scar formation in patients with coronary disease. Whether early formation of fQRS in patients with ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) is correlated with infarct size and prognosis is unknown. We assessed the prognostic value of fQRS at 60min post-PCI and its correlation with infarct size in patients with anterior STEMI managed with primary PCI. METHODS: The INFUSE-AMI trial enrolled 452 patients with anterior STEMI undergoing primary PCI. Electrocardiograms (ECGs) were performed at baseline and 60min post-PCI. Infarct size was evaluated using cardiac magnetic resonance imaging at 30days post-PCI. Target vessel failure (TVF) was defined as the composite of cardiac death, target vessel myocardial infarction, or ischemia-driven target vessel revascularization. Study groups were defined as patients with versus without fQRS at 60min post-PCI. RESULTS: Out of 421 patients with ECG data 60min post-PCI, 68 patients (16.2%) had fQRS. Patients with versus without fQRS had similar baseline characteristics and infarct size (16.9%±8.7% vs. 16.1%±10.5%, p=0.62), but patients with fQRS had higher adjusted risk of 1-year TVF (adjusted HR 2.27, 95% CI 1.06-4.89, p=0.036) and a trend toward a higher risk of the composite cardiac death or target vessel myocardial infarction (9.0% vs. 4.1%, p=0.08) at 1year. CONCLUSION: fQRS in patients with STEMI is associated with TVF but does not correlate with infarct size.

Role of QRS Fragmentation for Risk Stratification in Adults With Tetralogy of Fallot.

Background Patients with tetralogy of Fallot ( TOF ) remain at risk for cardiovascular events despite successful repair. Some of the current risk stratification tools require advanced imaging and invasive studies, and hence are difficult to apply to routine patient care. A recent study showed that QRS fragmentation ( QRS -f) is predictive of mortality in patients with TOF. The current study aims to validate this result by assessing whether severity of QRS -f could predict all-cause mortality in a different TOF population. Methods and Results The authors reviewed the Mayo Adult Congenital Heart Disease database for patients with TOF who had ECG from 1990-2017. QRS -f was defined as notches in QRS complex in ≥2 contiguous leads on ECG , not related to bundle branch block, and classified as none, mild (≤3 leads), moderate (4 leads), or severe (≥5 leads). Of 465 patients (age 37±14 years) in the study, QRS -f was present in 161 (35%): mild (n=43, 9%), moderate (n=77, 17%), and severe (n=41, 9%). There were 55 deaths (12%) during 13.6±8.2 years of follow-up. Severity of QRS -f remained an independent predictor of all-cause mortality after adjustment for other ECG parameters, patient demographics, and atrial and ventricular arrhythmia (hazard ratio, 1.74 per class; 95% confidence interval, 1.08-2.93 [ P=0.041]). Conclusions The presence of severe QRS -f may be used as complementary data to the usual clinical indices to determine whether interventions such as invasive electrophysiology study should be performed in patients with nonsustained ventricular tachycardia or to proceed with pulmonary valve replacement in patients with severe pulmonary regurgitation with ventricular volumes below the guideline-directed threshold for intervention.