QRS-Fragmentation: Perspectives for Use in Clinical Practice

The current article provides a detail review of foreign publications, discussing the opportunities and the benefits of evaluation of the QRS-fragmentation (fQRS) a new electrocardiographic (ECG) parameter in patients with coronary artery disease (CAD). Diagnostic criteria for narrow and wide QRS-complexes are defined. Main results of the comparative and correlation analysis, evaluating fQRS and electrocardiographic (pathologic Q-waves), echocardiographic (left ventricular ejection fraction), angiographic settings are described. There is a discussion of the prognostic role of fQRS in stable CAD as well as in patients presented with acute myocardial infarction. fQRS is an available ECG-marker of local myocardial fibrosis. It seems to be a useful negative predictor in individuals with CAD, indicating an increased risk of life-threatening ventricular arrhythmias and recurrent cardiac events. The presence of fragmented QRS-complexes is associated with an increased in-hospital and long term (overall as well as cardiovascular) mortality. Routine evaluation of fQRS in standard ECG leads does not require additional resources, and will contribute to an improvement in diagnostics and risk stratification of stable CAD as well as myocardial infarction. Assessment of fQRS can be included in noninvasive diagnostic algorithm concerning CAD.

Effectiveness of a new cardiac risk scoring model reclassified by QRS fragmentation as a predictor of postoperative cardiac event in patients with severe renal dysfunction

Background It is difficult to evaluate the risk of patients with severe renal dysfunction before surgery due to various limitations despite high postoperative cardiac events. This study aimed to investigate the value of a newly reclassified Revised Cardiac Risk Index (RCRI) that incorporates QRS fragmentation (fQRS) as a predictor of postoperative cardiac events in patients with severe renal dysfunction. Methods Among the patients with severe renal dysfunction, 256 consecutive patients who underwent both a nuclear stress test and noncardiac surgery were evaluated. We reclassified RCRI as fragmented RCRI (FRCRI) by integrating fQRS on electrocardiography. We defined postoperative major adverse cardiac event (MACE) as a composite of cardiac death, nonfatal myocardial infarction, and pulmonary edema. Results Twenty-eight patients (10.9%) developed postoperative MACE, and this was significantly frequent in patients with myocardial perfusion defect (41.4% vs. 28.0%, p = 0.031). fQRS was observed 84 (32.8%) patients, and it was proven to be an independent predictor of postoperative MACE after adjusting for the RCRI (odds ratio 3.279, 95% confidence interval (CI) 1.419–7.580, p = 0.005). Moreover, fQRS had an incremental prognostic value for the RCRI (chi-square = 7.8, p = 0.005), and to the combination of RCRI and age (chi-square = 9.1, p = 0.003). The area under curve for predicting postoperative MACE significantly increased from 0.612 for RCRI to 0.667 for FRCRI (p = 0.027) and 23 patients (32.4%) originally classified as RCRI 2 were reclassified as FRCRI 3. Conclusions A newly reclassified FRCRI that incorporates fQRS, is a valuable predictor of postoperative MACE in patients with severe renal dysfunction undergoing noncardiac surgery.

Predicting the coronary atherosclerosis severity in cardiac patients

Background. Coronary atherosclerosis is an ongoing pathological process, varying from asymptomatic forms to angina pectoris, myocardial infarction and even sudden cardiac death. Early identification of persons with an increased risk of the severe atherosclerosis will promote adequate diagnostic and therapeutic measures to prevent cardiovascular complications. Aim. To make a prognostic model determining the probability of a severe coronary atherosclerosis in cardiac patients. Material and methods. The actual study included 116 patients of cardiology departments with various degree of coronary atherosclerosis measured by coronary angiography: group I 70% coronary stenosis (50% in case of left main coronary artery), group II those with less severe atherosclerotic process. All patients underwent electrocardiography (ECG) at rest and Holter monitoring. Pathological Q-waves, qualitative and quantitative characteristics of ventricular extrasystoles as well as QRS-fragmentation were assessed in all cases. In individuals having sinus rhythm, heart rate turbulence (HRT), T-wave alternans and QT, QTc dispersion on maximum and minimum heart rate were additionally calculated. Results. The prognostic model included the following ECG-markers: HRT, pathological Q-waves, QTc dispersion on maximum heart rate and QRS-fragmentation in lateral leads (I, AVL, V6). All parameters have demonstrated a direct relationship with the likelihood of severe coronary atherosclerosis. The current model took into account 71% of the factors influencing significant atherosclerosis, AUC=0.940.04, the sensitivity and the specificity were 90.0 and 94.4% respectively. Conclusion. A comprehensive assessment of the ECG data helps to identify the group with an increased risk of severe coronary atherosclerosis among cardiac patients.

Sinus rhythm electrocardiogram depolarization abnormalities in patients with non-ischemic cardiomyopathy as predictors of myocardial scar

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Winkelman family research fund. Background. The arrhythmogenic substrate in nonischemic cardiomyopathy (NICM) characteristically consists of fibrosis with surviving myocytes. We hypothesized that the substrate may be reflected on the 12-lead ECG as depolarization abnormalities (QRS fragmentation [QRSf] and J waves) during sinus rhythm in patients with VT. Methods. Phase I subjects included a retrospective cohort with NICM and VT referred for VT ablation between 2007 and 2020 who had detailed substrate mapping. Phase II subjects included a prospective reference cohort with NICM and No VT referred for primary prevention ICD between 2017 and 2019. All patients had supraventricular rhythm. 12-lead ECGs voltage and presence of QRSf/J waves were compared between phase I and phase II patients. Results. Forty-five (59.2%) patients had epicardial (EPI) VT circuits and EPI LV low voltage. Thirty-one (40.8%) had endocardial (ENDO) VT circuits and Endo LV low voltage. All 38 Phase II subjects had cardiac magnetic resonance imaging (cMRI) with 26 (68.4%) patients demonstrating late gadolinium enhancement (LGE). Lower voltage in the limb leads was present in Phase I (NICM/VT) [DI (0.63 ± 0.33 vs 0.87 ± 0.4, p = 0.002), DII (0.6 ± 0.27 vs 0.85 ± 0.36, p < 0.001), DIII (0.59 ± 0.35 vs 0.74 ± 0.33, p = 0.03), AVR (0.53 ± 0.24 vs 0.75 ± 0.32, p < 0.001) and AVF (0.50 ± 0.26 vs 0.70 ± 0.28, p < 0.001)] than phase II (NICM/No VT) patients. A high prevalence of QRSf was observed in patients who had indices of LV scar with abnormal bipolar map or LGE on cMRI (ENDO 74.1% vs EPI 77.7%, p = 0.71 and LGE 73% vs No LGE 41.7%, p = 0.06). QRSf were noted in order of prevalence, in the inferior leads (ENDO 67.7% vs EPI 66.6%, p = 0.92), lateral leads (ENDO 35.5% vs EPI 48.9%, p = 0.24) and anterior leads (ENDO 22.6% vs EPI 22.2%, p = 0.97). The positive predictive value of inferior, lateral or anterior ≥2 QRSf leads as a predictor of regional scar among sustained VT patients was 92%, 97% and 88%, respectively. The presence of J waves was more frequently in patients with EPI substrate vs ENDO substrate (57.7% vs 9.6%, p < 0.001), and mainly noted in lateral and inferior leads. Conclusions. In patients with NICM and VT the presence and location of LV scarring can be predicted by depolarization abnormalities on 12-lead ECG. ECG characteristics NICM VT and EPI substrate(n = 45) NICM VT and ENDO substrate(n = 31) p value NICM No VT and LGE(n = 26) NICM No VT and No LGE(n = 12) p value QRSf in 2 contiguous leads 35 (77.7%) 23 (74.1%) p = 0.71 19 (73%) 5 (41.7%) p = 0.06 QRSf in lead DII, DIII, AVF 30 (66.6%) 21 (67.7%) p = 0.92 17 (65.4%) 5 (41.7%) p = 0.16 QRSf in lead DI, AVL, V5, V6 22 (48.9%) 11 (35.5%) p = 0.24 10 (38.5%) 3 (25%) p = 0.41 QRSf in lead V1, V2, V3, V4 10 (22.2%) 7 (22.6%) p = 0.97 9 (34.6%) 2 (16.7%) p = 0.25

Impact of electrophysiological features acquired after anatomical repair of congenital corrected transposition of the great arteries on late mortality and ventricular dysfunction

OBJECTIVES In patients with anatomically repaired congenitally corrected transposition of the great arteries, the impact of electrophysiological features on postoperative ventricular dysfunction remains less well known. Our goal was to investigate the role of fragmented QRS and QRS duration in mortality and systemic ventricular dysfunction after anatomical repair of corrected transposed great arteries. METHODS Consecutive patients who underwent anatomical repair in our institution from January 2005 to December 2017 were enrolled in this retrospective analysis. Fragmented QRS was defined as ≥1 discontinuous deflections in narrow QRS complexes, and ≥2 in wide QRS complexes, in 2 contiguous electrocardiogram leads. The primary end point was a composite of all-cause mortality and systemic ventricular dysfunction. RESULTS A total of 74 patients were included. Among them, 30, 15 and 29 underwent the Senning arterial switch, the Senning Rastelli and the hemi-Mustard/bidirectional Glenn/Rastelli procedures, respectively. The primary end point occurred in 9 (12.2%) patients and included 7 late deaths and 2 cases of late-onset systemic ventricular dysfunction. Fragmented QRS and QRS prolongation were noted in 19 (25.7%) and 21 (28.4%) patients, respectively. In patients with the primary end point, QRS fragmentation (6/9 vs 10/65; P < 0.001) and QRS prolongation (6/9 vs 15/65; P = 0.013) were noted more frequently than in patients without the primary end point. No statistical differences in these electrocardiogram findings were found among patients treated with 3 surgical strategies. CONCLUSIONS Appearance of QRS fragmentation or QRS prolongation is associated with death or ventricular dysfunction in anatomically repaired corrected transposition of the great arteries. Although there is a trend that QRS fragmentation and QRS prolongation appear more frequently in patients who had the Senning-arterial switch operation, there is no statistically significant difference associated with these electrocardiogram features among varied procedures.

Long-Term Follow-Up of Patients With Tetralogy of Fallot and Implantable Cardioverter Defibrillator

Background: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and sudden cardiac death represents an important mode of death in these patients. Data evaluating the implantable cardioverter defibrillator (ICD) in this patient population remain scarce. Methods: A Nationwide French Registry including all patients with tetralogy of Fallot with an ICD was initiated in 2010 by the French Institute of Health and Medical Research. The primary time to event end point was the time from ICD implantation to first appropriate ICD therapy. Secondary outcomes included ICD-related complications, heart transplantation, and death. Clinical events were centrally adjudicated by a blinded committee. Results: A total of 165 patients (mean age, 42.2±13.3 years, 70.1% males) were included from 40 centers, including 104 (63.0%) in secondary prevention. During a median (interquartile range) follow-up of 6.8 (2.5–11.4) years, 78 (47.3%) patients received at least 1 appropriate ICD therapy. The annual incidence of the primary outcome was 10.5% (7.1% and 12.5% in primary and secondary prevention, respectively; P =0.03). Overall, 71 (43.0%) patients presented with at least 1 ICD complication, including inappropriate shocks in 42 (25.5%) patients and lead dysfunction in 36 (21.8%) patients. Among 61 (37.0%) patients in primary prevention, the annual rate of appropriate ICD therapies was 4.1%, 5.3%, 9.5%, and 13.3% in patients with, respectively, 0, 1, 2, or ≥3 guidelines-recommended risk factors. QRS fragmentation was the only independent predictor of appropriate ICD therapies (hazard ratio, 3.47 [95% CI, 1.19–10.11]), and its integration in a model with current criteria increased the 5-year time-dependent area under the curve from 0.68 to 0.81 ( P =0.006). Patients with congestive heart failure or reduced left ventricular ejection fraction had a higher risk of nonarrhythmic death or heart transplantation (hazard ratio, 11.01 [95% CI, 2.96–40.95]). Conclusions: Patients with tetralogy of Fallot and an ICD experience high rates of appropriate therapies, including those implanted in primary prevention. The considerable long-term burden of ICD-related complications, however, underlines the need for careful candidate selection. A combination of easy-to-use criteria including QRS fragmentation might improve risk stratification. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03837574.

QRS fragmentation in children with suspected myocarditis: a possible additional diagnostic sign

Aims:We aim to assess the diagnostic role of QRS fragmentation in children with suspected acute myocarditis.Background:Diagnosis of myocarditis in the paediatric population is challenging. Clinical suspicion, electrocardiogram, and laboratory tests are the main diagnostic features at presentation. However, electrocardiogram in patients with myocarditis is usually considered aspecific. We have previously described QRS fragmentation in adult patients with acute myocarditis.Methods:Patients aged less than 18 years, admitted between 2003 and 2019, and discharged with a diagnosis of acute myocarditis were included. Standard electrocardiogram, laboratory, and echocardiographic findings at admission and follow-up were reviewed. QRS fragmentation was defined by the presence of multiphasic R′ spikes. Cardiac magnetic resonance and biopsy were performed in selected patients.Results:Twenty-one patients were analysed, 16 males (76%), median age 9.5 (2.5–16) years. At presentation, 12 patients (57%) displayed QRS fragmentation. Median ejection fraction was 40% (27–60). Nine patients (43%) underwent cardiac magnetic resonance and displayed late gadolinium enhancement. One patient underwent biopsy that showed borderline findings. Electrocardiogram leads showing QRS fragmentation correlated with distribution of late gadolinium enhancement. Median follow-up was 600 (190–2343) days. All patients were alive at last follow-up. Six patients (33%) patients displayed persistence of QRS fragmentation. Median ejection fraction was 60% (60–65%). In three patients (14%), ejection fraction remained depressed, two of which showed persistence of QRS fragmentation.Conclusion:In this cohort of children with suspected myocarditis, QRS fragmentation was confirmed as a new additional diagnostic finding to look for at admission and during follow-up.