Fragmented QRS Is a Novel Risk Factor for Ventricular Arrhythmic Events After Receiving Cardiac Resynchronization Therapy in Nonischemic Cardiomyopathy

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.

Fragmented QRS Is Independently Predictive of Long-Term Adverse Clinical Outcomes in Asian Patients Hospitalized for Heart Failure: A Retrospective Cohort Study

Background: Fragmented QRS (fQRS) results from myocardial scarring and predicts cardiovascular mortality and ventricular arrhythmia (VA). We evaluated the prevalence and prognostic value of fQRS in Asian patients hospitalized for heart failure.

Methods and Results: This was a retrospective cohort study of adult patients hospitalized for heart failure between 1st January 2010 and 31st December 2016 at a tertiary center in Hong Kong. The baseline ECG was analyzed. QRS complexes (<120 ms) with fragmented morphology in ≥2 contiguous leads were defined as fQRS. The primary outcome was a composite of cardiovascular mortality, VA, and sudden cardiac death (SCD). The secondary outcomes were the components of the primary outcome, myocardial infarction, and new-onset atrial fibrillation. In total, 2,182 patients were included, of whom 179 (8.20%) had fQRS. The follow-up duration was 5.63 ± 4.09 years. fQRS in any leads was associated with a higher risk of the primary outcome (adjusted hazard ratio (HR) 1.428 [1.097, 1.859], p = 0.001), but not myocardial infarction or new-onset atrial fibrillation. fQRS in >2 contiguous leads was an independent predictor of SCD (HR 2.679 [1.252, 5.729], p = 0.011). In patients without ischaemic heart disease (N = 1,396), fQRS in any leads remained predictive of VA and SCD (adjusted HR 3.526 [1.399, 8.887], p = 0.008, and 1.873 [1.103, 3.181], p = 0.020, respectively), but not cardiovascular mortality (adjusted HR 1.064 [0.671, 1.686], p = 0.792).

Conclusion: fQRS is an independent predictor of cardiovascular mortality, VA, and SCD. Higher fQRS burden increased SCD risk. The implications of fQRS in heart failure patients without ischaemic heart disease require further studies.

Fragmented QRS is associated with ventricular arrhythmias in heart failure patients: A systematic review and meta-analysis

INTRODUCTION

Many primary prevention heart failure (HF) patients with an implantable cardiac defibrillator (ICD) rarely experience life-threatening ventricular arrhythmias (VA). New strategies are required to identify patients most at risk of VA and sudden cardiac death who would benefit from an ICD. One potential method is the detection of fragmented QRS (fQRS) on the electrocardiogram. The aim was to assess the predictive capacity of fQRS for VA and mortality in ischemic (ICM) and non-ischemic cardiomyopathy (NICM) primary prevention HF patients.

METHODS AND RESULTS

A systematic review and meta-analysis of studies examining fQRS in HF patients with or without an ICD who met primary prevention indications with reduced ejection fraction ≤40%. Outcome measures were VA (or appropriate ICD therapy) and all-cause mortality. Ten studies involving 3885 patients were included for analysis. Most patients were male with non-fQRS patients being significantly younger (-1.5[-2.66, -0.42], p = .03). Diabetes was more likely in fQRS patients (1.12[1.01, 1.25], p = .03) while non-fQRS patients were 28% more likely to have a history of atrial fibrillation (0.82[0.67,1.00], p = .05). Ventricular arrhythmias were significantly 1.5 times more likely in patients with fQRS (1.51[1.02, 2.25], p = .04). HF patients were 1.7 times more likely to die of any cause if fQRS was present (1.68[1.13, 2.52], p = .01). NICM patients with fQRS have a significant 2.6-fold increased incidence of death compared with ICM patients (2.55[1.63, 3.98], p < .0001).

CONCLUSION

fQRS is associated with VA and all-cause mortality and may be a novel marker in the risk stratification of primary prevention HF patients indicated for ICD implantation.

Prognostic value of fragmented QRS complex in patients with acute myocardial infarction

BACKGROUND

Several factors and risk stratification tools have been studied to determine the prognosis of acute coronary syndrome. Fragmented QRS (fQRS) is a marker of myocardial scar and its prognostic role has recently been demonstrated. The present study aimed to investigate the association between the presence of fQRS in electrocardiogram and the prognosis of ST-segment elevation and non-ST-segment elevation myocardial infarction (STEMI and NSTEMI).

METHODS

A total of 661 patients with myocardial infarction (MI) were enrolled in a retrospective study. Based on the presence of fQRS in admission electrocardiogram, patients were divided into two groups. All patients were followed up for 6 months, and all major adverse cardiovascular events (MACE) were recorded.

RESULTS

The mean age of patients was 61.3 ± 1.2 years, and 71.7% were male. In the acute phase, the detection rates of regional wall motion abnormality and aortic valve insufficiency were higher in positive fQRS compared to negative fQRS group (p = 0.003). The incidence of total MACE was significantly higher in the positive fQRS compared to the negative fQRS group among all patients and in both STEMI and NSTEMI subgroups (p < 0.001). Based on multivariate analysis, the presence of fQRS and hypertension were the strongest predictors of total MACE at 6‑month follow-up (odds ratio [OR] = 5.929; 95% confidence interval [CI] = 3.620-9.709; p < 0.001 and OR = 2.220; 95% CI = 1.390-3.547; p < 0.001, respectively).

CONCLUSION

Regardless of the type of MI, it was found that the presence of fQRS on admission electrocardiogram can be implemented in risk stratification tools in patients with acute MI.

Quantification of abnormal QRS peaks predicts response to cardiac resynchronization therapy and tracks structural remodeling

Background

Although QRS duration (QRSd) is an important determinant of cardiac resynchronization therapy (CRT) response, non-responder rates remain high. QRS fragmentation can also reflect electrical dyssynchrony. We hypothesized that quantification of abnormal QRS peaks (QRSp) would predict CRT response.

Methods

Forty-seven CRT patients (left ventricular ejection fraction = 23±7%) were prospectively studied. Digital 12-lead ECGs were recorded during native rhythm at baseline and 6 months post-CRT. For each precordial lead, QRSp was defined as the total number of peaks detected on the unfiltered QRS minus those detected on a smoothed moving average template QRS. CRT response was defined as >5% increase in left ventricular ejection fraction post-CRT.

Results

Sixty-percent of patients responded to CRT. Baseline QRSd was similar in CRT responders and non-responders, and did not change post-CRT regardless of response. Baseline QRSp was greater in responders than non-responders (9.1±3.5 vs. 5.9±2.2, p = 0.001) and decreased in responders (9.2±3.6 vs. 7.9±2.8, p = 0.03) but increased in non-responders (5.5±2.3 vs. 7.5±2.8, p = 0.049) post-CRT. In multivariable analysis, QRSp was the only independent predictor of CRT response (Odds Ratio [95% Confidence Interval]: 1.5 [1.1–2.1], p = 0.01). ROC analysis revealed QRSp (area under curve = 0.80) to better discriminate response than QRSd (area under curve = 0.67). Compared to QRSd ≥150ms, QRSp ≥7 identified response with similar sensitivity but greater specificity (74 vs. 32%, p<0.05). Amongst patients with QRSd <150ms, more patients with QRSp ≥7 responded than those with QRSp <7 (75 vs. 0%, p<0.05).

Conclusions

Our novel automated QRSp metric independently predicts CRT response and decreases in responders. Electrical dyssynchrony assessed by QRSp may improve CRT selection and track structural remodeling, especially in those with QRSd <150ms.

Comparing of Tp-Te Interval and Tp-Te/Qt Ratio in Patients with Preserved, Mid-Range and Reduced Ejection Fraction Heart Failure

BACKGROUND

Heart failure (HF) is classified in three class: HF with preserved EF (HFpEF); normal or LVEF ≥ 50%, HF with reduced EF (HFrEF); LEVF < 40% and newly HF mid-range EF (HFmrEF); LVEF 40-49%. On Electrocardiography (ECG) T wave, Tpeak-Tend (Tp-Te) interval reflects transmural dispersion of repolarisation (TDR) which of these indexes have been proposed as predictors of risk for ventricular arrhythmia (VA) in many cardiac diseases.

AIM

Aim of this study to asses these indices of TDR among three HF class.

METHODS

Total of 192 patients were included in this study.

RESULTS

Many of indices like Tp-Te, Tp-Te/QT wasn't different between groups (P > 0.05). But mean Q-Tpeak (QTp), S-Tend (S-Te) and S-Tpeak (S-Tp) were found significantly different between groups (P < 0.05). Again S-Te was found different according to having fragmented QRS (fQRS) on ECG (P = 0.031). Comparing to mitral inflow E/A parameters showed significant differences for Tp-Te, Tp-Tec, Tp-Te/QT, Tp-Te/QTc and Tp-Tec/QTc parameters. Finally, we found correlations between S-Te and white blood cell (WBC) (r = - 0.171; P = 0.037) and S-Tp and WBC (r = - 0.170; P = 0.038) and between S-Te and fQRS (r = 0.158; P = 0.031).

CONCLUSIONS

We didn't find differences for many of indices of TDR like Tp-Te interval between groups except QTp, S-Te, S-Tp intervals. Also, S-Te and fQRS showed significant correlation. For prediction of ventricular arrhythmia and cardiovascular death newer indexes on ECG are needed to be established in the future which will make us facilitate to distinguish high risk patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Analysis of the High-Frequency Content in Human QRS Complexes by the Continuous Wavelet Transform: An Automatized Analysis for the Prediction of Sudden Cardiac Death

BACKGROUND

Fragmentation and delayed potentials in the QRS signal of patients have been postulated as risk markers for Sudden Cardiac Death (SCD). The analysis of the high-frequency spectral content may be useful for quantification.

METHODS

Forty-two consecutive patients with prior history of SCD or malignant arrhythmias (patients) where compared with 120 healthy individuals (controls). The QRS complexes were extracted with a modified Pan-Tompkins algorithm and processed with the Continuous Wavelet Transform to analyze the high-frequency content (85-130 Hz).

RESULTS

Overall, the power of the high-frequency content was higher in patients compared with controls (170.9 vs. 47.3 10³nV²Hz^-1; p = 0.007), with a prolonged time to reach the maximal power (68.9 vs. 64.8 ms; p = 0.002). An analysis of the signal intensity (instantaneous average of cumulative power), revealed a distinct function between patients and controls. The total intensity was higher in patients compared with controls (137.1 vs. 39 10³nV²Hz^-1s^-1; p = 0.001) and the time to reach the maximal intensity was also prolonged (88.7 vs. 82.1 ms; p < 0.001).

DISCUSSION

The high-frequency content of the QRS complexes was distinct between patients at risk of SCD and healthy controls. The wavelet transform is an efficient tool for spectral analysis of the QRS complexes that may contribute to stratification of risk.

Protective effects of N(2)‑L‑alanyl‑L‑glutamine mediated by the JAK2/STAT3 signaling pathway on myocardial ischemia reperfusion

To explore the protective effect of N(2)-L-alanyl-L-glutamine (NLAG) on myocardial ischemia-reperfusion injury (IRI), and observe the influence of NLAG on the Janus activated kinase signal transducer 2 and activator of transcription 3 (JAK2/STAT3) signaling pathway‑associated molecules. Wistar rats were randomly divided into three groups: Sham, IRI and NLAG. In the IRI rat model, the cardiac hemodynamics, the maximum rate of left ventricular pressure (+dP/dtmax) and the left ventricular end‑diastolic pressure (LVDP) were recorded. Hematoxylin‑eosin and Masson staining were used to detect myocardial histological changes. The levels of plasma interleukin (IL)‑1β and ‑6, tumor necrosis factor (TNF)‑α, lactase dehydrogenase (LDH), troponin (cTn)I, creatine kinase (CK), heart type fatty acid binding protein (hFABP), malondialdehyde (MDA) and succinate dehydrogenase (SDH) were determined with ELISA. The protein expression levels of B‑cell lymphoma (Bcl)‑2, Bcl2‑associated X protein (Bax), Caspase‑3, JAK2, phosphorylated (p)‑JAK2, STAT3 and p‑STAT3 were detected by western blot analysis. The IRI model demonstrated notable myocardial injury; myocardial cells were arranged disorderly with some nuclei disappearing, and cardiac muscular fibers were degenerated. Following 60 min of reperfusion, LVDP, HR and +dP/dtmax were 31.3±4.53 mmHg, 239.17±8.45 beats/min and 615.17 mmHg/sec, respectively. Compared with the Sham group, the levels of LDH, cTnI, CK, hFABP release, inflammatory factors (IL‑1β, IL‑6 and TNF‑α) and oxygen free radical (MDA and SDH) levels were increased in the IRI group. In the NLAG group, myocardial injury was improved, the concentrations of LDH, cTnI, CK, hFABP, IL‑1β, IL‑6, TNF‑α, MDA were decreased, and SDH release was increased compared with the IRI group. In addition, NLAG significantly increased Bcl‑2, JAK2, p‑JAK2, STAT3 and p‑STAT3 protein expression, and decreased Bax protein expression compared with the IRI group. In conclusion, myocardial ischemia‑reperfusion can lead to myocardial cell apoptosis and myocardial injury and NLAG attenuates the IRI‑induced mitochondrial oxidative stress injury and apoptosis by activating the JAK2/STAT3 signaling pathway, thus exerting protective effects against IRI.