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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. [ABSTRACT FROM AUTHOR]

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. The fragmented QRS complex in lead V1 in young athletes. PPS = preparticipation screening; EST = exercise stress test; fQRSV1 = fragmented QRS in lead V1; PSBs = premature supraventricular beats; PVBs = premature ventricular beats. [ABSTRACT FROM AUTHOR]

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

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. [ABSTRACT FROM AUTHOR]

Abstract 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.

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. [ABSTRACT FROM AUTHOR]

Abstract 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

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. [ABSTRACT FROM AUTHOR]

Abstract 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.

Abstract 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.

Objective: The aim of this study was to investigate the relationship between the presence of fragmented QRS (f-QRS) complex on electrocardiography (ECG) and maternal demographic characteristics and left ventricular systolic and diastolic dysfunction on echocardiography. Materials and Methods: 473 pregnant women enrolled in this study and divided into two groups. (f-QRS positive group n=77, f-QRS negative group n=396 ). Maternal demographic features and echocardiographic parameters of all participants were recorded and compared between two groups. Results: The mean age of the study population was 27.70 ± 5.62 and mean gestational week was 7.37 ± 1.55. Parity in f-QRS positive group was higher than in control group (p=0.01). There was a statistically significant trend between fragmentation frequency and parity number (p=0.002). There were no significant differences between two groups in terms of age, gestational week, heart rate, body mass index. Left ventricle end-systolic and diastolic diameters and left ventricular ejection fraction were similar between the two groups Conclusions: The presence of f-QRS was correlated with increase in number of parity and we suggest that multiparity may be a risk factor for cardiac events during pregnancy. Pregnant women with f-QRS on their rest ECG need extra attention in terms of cardiovascular disease. By demonstrating clinical significance of f-QRS, this simple tool might be used to determine women who could be at risk for developing cardiac dysfunction in pregnancy.

Pulse wave amplification and augmentation are considered as new indicators of arterial stiffness. It is of interest to study their association with electrocardiographic pro-arrhythmic patterns in the male population of Novosibirsk. Material and methods. We used data from a representative sample of 145 men aged 25-44 years from a population of inhabitants of Novosibirsk. Applanation tonometry of the radial artery and pulse wave analysis were performed using the SphygmoCor system (AtCorMedical, Australia). The Brugada pattern, the pattern of early ventricular repolarization and fragmentation of the QRS complex were determined on a resting electrocardiogram according to generally accepted current criteria. When analyzing the data, descriptive statistics methods and the general linear model (GLM) were used. Results. Fragmentation of the QRS complex in the in the area of the inferior wall of the left ventricle, regardless of age, body mass index and heart rate, was associated with a decrease in the ratio of amplification of pulse pressure (F = 5.34; p = 0.022), amplification of pulse pressure (F = 5.91; p = 0.016) and amplification of systolic pressure (F = 5.02; p = 0.027). Conclusion. In the Novosibirsk male population, a decrease in pulse wave amplification was associated with fragmentation of the QRS complex. The results of this study demonstrate the relevance of an integrated assessment of prognostically significant indicators of arterial stiffness and ventricular pro-arrhythmia to study the possible cumulation of cardiovascular risk.

Abstract 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 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.

• Electrocardiography (ECG) is valuable and ubiquitously available for screening for cardiac sarcoidosis. • Patients with an extra-cardiac manifestation should frequently be evaluated by ECG. • QRS broadening, fragmentation, and T-Wave abnormalities may be promising. 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. [ABSTRACT FROM AUTHOR]

Introduction: Idiopathic ventricular tachycardia and ventricular fibrillation, as causes of sudden cardiac death, are entities with mechanisms poorly studied and understood to date. The electrocardiogram (ECG) is a simple tool, but with great diagnostic and prognostic value, which has allowed the identification of certain markers associated with increased risk of development of malignant ventricular arrhythmias and sudden cardiac death. Methods: To identify the electrocardiographic markers related to the risk of developing idiopathic malignant ventricular arrhythmias, a review of the literature was performed, looking for the most recent articles with the greatest scientific impact on the topic. Outcome: Although the number of studies published to date is scarce, the published evidence has shown three electrocardiographic risk markers that have emerged in recent years and which have been related to the development of idiopathic malignant ventricular arrhythmias: the early repolarization (ER) pattern, QRS fragmentation (QRSF) and the Tpeak-Tend (Tp-Te) interval. The ECG marker that has shown most evidence to date is the pattern of ER, as a cause of changes in both ventricular depolarization and repolarization. The QRSF and the Tp-Te interval have also been related to the development of idiopathic ventricular arrhythmias, although with less evidence in this regard. Conclusion: In the last years, three electrocardiographic markers have appeared as variables related to the development of malignant ventricular arrhythmias, as is the case of ER, QRSF and Tp-Te interval. However, evidence is scarce in this specific patient profile and further randomized clinical trials are necessary to demonstrate its true relationship and usefulness.

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.

The dangerous electrophysiological shifts in the myocardium, with the exception of rare congenital canalopathies, are overwhelmingly secondary, being a consequence of various pathological conditions. These processes, in turn, can also be genetically determined. Thus, the association of indices of ventricular repolarization with polymorphism of adrenoreceptor genes is shown. The electrical instability of the myocardium, apparently, has a multigenic and multifactorial basis. The aim of the study was to study the relationship between the risk factors and the polymorphism of the ADRB1 gene with pro-arrhythmic electrocardiographic patterns in the general population of Novosibirsk. Material and methods. Materials of epidemiological study of the general population of Novosibirsk under the WHO project «MONICA» (a sample of 831 men aged 25-64 years) were used. For genetic research 195 people were randomly selected. ECG-patterns were identified in a 30 % subsample - 261 people. The number of people with both genetic and electrocardiographic data was 105 people. According to the WHO criteria, components of the metabolic syndrome were identified. The A145G (rs1801252) polymorphism of the ADRB1 gene was determined. The Brugada, early repolarization, QRS fragmentation patterns were detected according to current criteria. The multivariate general linear model (GLM) were applied. Results. The QRS fragmentation was independently associated with obesity ( p = 0.014), increased TG level ( p = 0.040), decreased HDL cholesterol level ( p = 0.00079) and polymorphism of the ADRB1 gene (p = 0.00019). Conclusion. The integral approach is advisable in analyzing the genetic, metabolic and electrophysiological factors causing the electrical instability of the myocardium.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim. To investigate on the QRS complex fragmentation (fQRS) in patients with idiopathic ventricular arrhythmias (VA) .Material and methods. Totally, 125 patients, selected into 2 groups: 1st group — 100 patients (mean age 46,4±14,1 y., 69 females) with idiopathic VRD. Patients had predominating daytime arrhythmia (63%), more oftenly — monomorphic ventricular exstrasystolic complexes (VE) (59%), in 39% patients — paroxysms of nonsustained ventricular tachicardia. Structural pathology of myocardium was ruled out based on electrocardiography data, echocardiography, in some cases — magnetic resonance. Second, control group — 25 pts. (69,0±11 y. o., 12 females) with VRD of ischemic origin (coronary heart disease, myocardial infarction in anamnesis). In this group, polymorphic (84%) daytime (68%) VE predominated, and in 25% — nonsustained ventricular tachicardia. Analysis was done with Holter ECG in 12 leads (“KTResult 2”, “Inkart” JSC).Results. In the 1st group, fQRS of sinus complexes was registered in 2 patients (2%) and was transient. Relations in 24-hour dynamics of fQRS were not found. FQRS in VE was registered in 25 patients (25%). One patient had fQRS of sinus complexes as well as fQRS in VE. In 17 patients (68%) fQRS was found in VE. In controls, fQRS of sinus complexes was found in 6 patients (24%), fQRS of VE — in 23 (92%) and was permanent.Conclusion. The phenomenon of fQRS can be found during routine instrumental investigation (standard ECG or Holter ECG), and is more common for CHD patients, being significant criteria for repolarization processes evaluation. Looking for fQRS in patients with idiopathic VRD, probably, is related to dysbalance of autonomous nervous regulation that leads to electrical instability of myocardium. It cannot be ruled out that fQRS might be an early marker of cardiomyopathies. It is necessary to investigate on this phenomenon further and to find its place in risk stratification of sudden cardiac death of patients with no structural heart pathology.

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.

Objective: Fragmented QRS (fQRS) is an accessible biomarker and indication of myocardial scarring that can be detected from the electrocardiogram (ECG). Nowadays, fQRS scoring is done on a visual basis, which is time consuming and leads to subjective results. This study proposes an automated method to detect and quantify fQRS in a continuous way using features extracted from variational mode decomposition (VMD) and phase-rectified signal averaging (PRSA). Methods: In the proposed framework, QRS complexes in the ECG signals were first segmented using VMD. Then, ten VMD- and PRSA-based features were computed and fed into well-known classifiers such as support vector machine (SVM), K-nearest neighbors (KNN), Naive Bayesian (NB), and TreeBagger (TB) in order to compare their performance. The proposed method was evaluated with 12-lead ECG data of 616 patients from the University Hospitals Leuven. The presence of fQRS in each ECG lead was scored by five raters. Both detection and quantification of fQRS could be achieved in this way. Results: The experimental results indicated that the proposed method achieved AUC values of 0.95, 0.94, 0.90, and 0.89 using SVM, KNN, NB, and TB classifiers, respectively, for detecting QRS fragmentation. Assessment of quantification performance was done by comparing the fQRS score with the total score, obtained by summing the scores from the individual raters. Results showed that the fQRS score clearly correlated with this estimate of fQRS certainty. Conclusion: The proposed method obtained good results in both fQRS detection and quantification, and is a novel way of assessing the certainty of QRS fragmentation in the ECG signal. [ABSTRACT FROM AUTHOR]

The arrhythmogenic right ventricular dysplasia or cardiomyopathy is a genetic heart disease whose diagnosis is often a challenge for the clinician. It is one of the most common causes of sudden cardiac death in adolescence and in young adults. We present the case of a patient with a history of malignant ventricular arrhythmias and recovered sudden cardiac death due to arrhythmogenic right ventricular dysplasia, with QRS fragmentation in the right precordial leads, as a marker of the presence of a suitable substrate for the emergence of spontaneous ventricular fibrillation. The pathogenesis, diagnosis and treatment of this disease are discussed. [ABSTRACT FROM AUTHOR]

The electrocardiogram (ECG) is a commonly available basic diagnostic modality in in-patient, out-patient, and emergency departments. In patients with coronary artery disease (CAD), the presence of a fragmented QRS (f-QRS), which is an extra R wave (R′), notching of the single R wave, notching of the S wave in at least two contiguous leads on the 12-lead ECG, is associated with a myocardial scar from previous myocardial injury. Furthermore, the presence of f-QRS has been shown to be associated with adverse outcomes in CAD and non-CAD patients. In the present paper, we will solely focus on the usefulness and utilization of f-QRS in predicting ventricular tachyarrhythmia in many heart diseases, that is, ischemic cardiomyopathy, non-ischemic cardiomyopathy, hypertrophic obstructive cardiomyopathy, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy. In the majority of such cases, ventricular tachyarrhythmia results in sudden cardiac death. Diagnosing them beforehand can lead to prevention and/or early treatment of these arrhythmias to prevent potential morbidity and mortality.

Introduction: We aimed to evaluate the effect of exercise-based cardiac rehabilitation (CR) on the fragmented QRS (fQRS) in patients with ST elevation myocardial infarction (STEMI). Methods: Ninety-seven patients with STEMI participated CR and 81 patients as a control group were included to the study. The trained patients were grouped according to the presence and persistence of QRS fragmentation on the electrocardiogram (ECG) before and after CR. If the fragmentation was present on the ECG at the beginning of the CR but not on the ECG at the end of CR; the transient group, if the fQRS persists after CR; the persistent fQRS group. ECGs obtained from the control group were grouped according to the presence of a fQRS on ECG. Results: Among the trained patients, 45 (46%) did not have a fQRS before CR, whereas 52 (54%) presented a fQRS before CR, which was persistent in 35 patients (the persistent fQRS group) and transient in 17 patients (the transient fQRS group). Among 81 patients included in the control group, fQRS was persistent in 41 patients. Presence of fQRS on the ECG was significantly decreased with CR and it is better in trained group than the control group (P=.034). There were not significant correlations with other characteristics, except hypertension. Conclusion: The existence of the fQRS decreases after CR in patients with STEMI especially in hypertensive individuals, which may be related to improved electrical stability in the myocardium as a predictor of increase in survival and decrease in major cardiac events.

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Right bundle branch block is relatively frequent in the general population and is generally considered benign in healthy individuals. However, it has been associated with increased cardiovascular risk and all-cause mortality in various cohort studies. Indeed, the presence of right bundle branch block in subjects affected by cardiomyopathies or channelopathies is not rare and may conceal underlying electrocardiographic changes, thus making the diagnosis of such conditions more challenging. The purpose of this review is to analyze the prevalence and clinical significance of right bundle branch block in subjects affected by Brugada syndrome and arrhythmogenic right ventricular cardiomyopathy. [ABSTRACT FROM AUTHOR]

Abstract: Background: The study was designed to investigate the effect of heart rate and pacing mode on QRS fragmentation (f‐QRS). Moreover, the usefulness of f‐QRS in distinguishing patients with impaired left ventricular ejection function (EF) and ventricular tachycardia (VT) from patients with normal EF was assessed. Methods: Three hundred and six recipients, with dual‐chamber device, with intrinsic narrow or wide QRS complex and preserved atrioventricular conduction were grouped into normal‐EF or impaired‐EF VT. We analyzed intrinsic narrow f‐QRS and wide f‐QRS as well as ventricular‐paced f‐QRS following different heart rates (baseline, 100 bpm) and pacing modes. Results: In the baseline state, overall, patients with impaired‐EF VT (35 ± 9%), compared to those with normal‐EF, had more f‐QRS (56% vs 27%, P < .001) and ventricular‐paced f‐QRS (62% vs 16%, P < .0001). Ventricular pacing conferred both at baseline and at higher heart rate more ventricular‐paced f‐QRS in patients with impaired‐EF VT than in normal‐EF (P < .001). Detection of ventricular‐paced f‐QRS markedly improved overall specificity (84%) and positive predictive value (91%) in identifying patients with impaired‐EF VT. Conclusions: Increased heart rate or/and ventricular pacing uncover QRS fragmentations. Detection of ventricular‐paced f‐QRS adds value toward noninvasive identification of patients with impaired‐EF VT. [ABSTRACT FROM AUTHOR]

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 60 min 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 60 min post-PCI. Infarct size was evaluated using cardiac magnetic resonance imaging at 30 days 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 60 min post-PCI. Results Out of 421 patients with ECG data 60 min 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 1 year. Conclusion fQRS in patients with STEMI is associated with TVF but does not correlate with infarct size. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background There seems to be a significant arrhythmia burden in β-thalassemia major (TM) patients without overt cardiomyopathy. Apart from conventional electrocardiographic (ECG) and arrhythmic risk markers we studied novel markers of ventricular repolarization and autonomic imbalance both at rest and after exercise testing. Methods We studied 47 adult TM patients without systolic heart failure and 47 age and sex-matched healthy control subjects. The median age of the studied population was 36 [32–43] years, 57% men. Baseline demographic and clinical characteristics were recorded while 12-lead electrocardiograms, 24-hour ECG Holter recordings, and treadmill exercise stress tests were analyzed. Results TM patients exhibited increased QTc intervals in both 12-lead ECG recordings and in 24-hour Holter recordings. In addition, they had increased indexes of ventricular repolarization heterogeneity such as QT dispersion, and T peak-to-end/QT ratios. Furthermore, TM patients had decreased indexes of heart rate variability while the heart rate recovery after exercise was significantly attenuated compared to controls. Also, they had increased P wave and QRS duration while the QRS fragmentation was very prevalent. Finally, premature atrial extrasystoles and paroxysmal atrial fibrillation episodes were more frequent in TM patients. Conclusions TM patients with preserved left ventricular systolic function have several ECG abnormalities including alterations in ventricular depolarization and repolarization. Also, cardiac autonomic dysfunction is evident in 24-hour ECG monitoring as well as in the recovery phase after exercise testing. The prognostic value of specific arrhythmic risk indexes in this setting remains to be elucidated. [ABSTRACT FROM AUTHOR]

The electrocardiogram (ECG) is a commonly available basic diagnostic modality in in-patient, out-patient, and emergency departments. In patients with coronary artery disease (CAD), the presence of a fragmented QRS (f-QRS), which is an extra Rwave (R'), notching of the single Rwave, notching of the S wave in at least two contiguous leads on the 12-lead ECG, is associated with a myocardial scar from previous myocardial injury. Furthermore, the presence of f-QRS has been shown to be associated with adverse outcomes in CAD and non-CAD patients. In the present paper, we will solely focus on the usefulness and utilization of f-QRS in predicting ventricular tachyarrhythmia in many heart diseases, that is, ischemic cardiomyopathy, nonischemic cardiomyopathy, hypertrophic obstructive cardiomyopathy, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy. In the majority of such cases, ventricular tachyarrhythmia results in sudden cardiac death. Diagnosing them beforehand can lead to prevention and/or early treatment of these arrhythmias to prevent potential morbidity and mortality. [ABSTRACT FROM AUTHOR]

Background: Conduction abnormalities are involved in the pathogenesis of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS).Objective: We investigated whether right ventricular apical pacing (RVAP) could enhance the conduction abnormality and predict the susceptibility to VF in patients with BrS.Methods: Twenty patients with BrS (n = 15) or early repolarization syndrome (ERS) (n = 5) having an implantable cardioverter-defibrillator and 11 patients with complete atrioventricular block having a pacemaker were studied.Results: In BrS, 7 patients had a history of spontaneous VF [VF(+) group] and the remaining 8 did not [VF(-) group]. The number of spikes in fragmented QRS was counted during sinus rhythm and RVAP at rates of 80 and 110 beats/min, respectively. Patients with complete atrioventricular block had no spikes during RVAP. During sinus rhythm, no significant difference was observed in QRS spike numbers among VF(+), VF(-), and ERS groups. During RVAP at 110 beats/min, the sum of spike numbers in leads V1 and V2 increased and the duration of QRS fragmentation increased in the VF(+) group as compared with VF(-) and ERS groups [VF(+): 10.7 ± 3.7, 2.4 ± 3.2, and 2.4 ± 1.8 ms; P < .001; VF(-): 173 ± 32, 45 ± 44, and 49 ± 45 ms; P < .001]. According to the receiver operating characteristic analysis, the cutoff value of the sum of spike numbers in leads V1 and V2 to best discriminate between VF(+) and VF(-) groups was 4 in patients with BrS.Conclusion: RVAP manifested QRS fragmented spikes, which could be associated with spontaneous VF in patients with BrS. [ABSTRACT FROM AUTHOR]

Background Presence of fragmented QRS (fQRS) complex in a 12-lead electrocardiogram (ECG) has been shown to represent alternation of myocardial activation owing to myocardial scar. The aim of this study was to investigate whether presence of fQRS complex predicts in-hospital and longterm mortality in patients with acute pulmonary embolism (APE). Methods This study included 186 consecutive patients with APE. Computed tomography pulmonary angiography (CTPA) was used to diagnose APE. ECG was obtained immediately after admission. Results Patients were divided into two groups: patients who had fQRS on their ECG (n = 52), and patients who did not have fQRS on their ECG (n = 134). The fQRS was associated with not only in-hospital mortality (P = 0.02) but also long-term mortality (P = 0.01). Furthermore, the fQRS was found to be a significant predictor of in-hospital and long-term mortality in multivariable Cox analyses. Conclusion In this study, fQRS was found to be predictors of both in-hospital and long-term mortality. Electrocardiography can be used to detect high-risk patients in APE; moreover, it bears little risk, is inexpensive, and easy to perform. [ABSTRACT FROM AUTHOR]

Fragmented Paced QRS and ATP Effectiveness 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. [ABSTRACT FROM AUTHOR]