Prolonged QRS Duration Research Articles

Prevalence, characteristics and predictors of left bundle branch block induced cardiomyopathy following transcatheter aortic valve implantation

Abstract Background Left bundle branch block is a relatively common conduction disturbance that can occur as a complication of transcatheter aortic valve implantation (TAVI) procedures. LBBB-induced cardiomyopathy (LBBB-CM) develops due to the mechanical dyssynchrony caused by the conduction abnormality. This dyssynchrony can lead to adverse left ventricular remodeling over time, resulting in a decline in cardiac function. Nevertheless, data on iatrogenic LBBB due to TAVI resulting in cardiomyopathy is lacking. Purpose To investigate the prevalence, characteristics and predictors for LBBB-CM following TAVI. Methods This was a retrospective single center study. A total of 1792 patients underwent TAVI between 2013 and 2021. New LBBB was documented in medical records in 353 patients. After exclusions (figure 1), we remained with 88 patients who were discharged from hospital with complete LBBB, had no pacemaker in situ and had at least 1 year of follow-up. The median follow-up in this study was 40 [17-64] months. LBBB-CM was defined as an absolute decline of >10% in ejection fraction (EF) due to clear septal dyssynchrony and in the absence of an alternative explanation. Results A total of 8 out of 88 patients (9%) developed LBBB-CM over the study period. During the first two years of follow-up, the prevalence was low but gradually increased with extended follow-up. The mean age at discharge from hospital in LBBB-CM group was 83 ± 5 years and the mean EF was 59% ± 3. Patients in the LBBB-CM group had a longer PR interval compared to the no LBBB-CM group (255 ±36 vs 191 ± 38ms, p=0.02) and were more likely to have atrial fibrillation at discharge (50% vs 6%, p<0.001). On Cox regression analysis, both PR interval and QRS duration were identified as significant predictors for the development of LBBB-CM. The HR for PR interval was 1.04 (95% CI 1-1.07, p=0.02) and HR for QRS duration was 1.12 (95% CI 1-1.25, p=0.05). Conclusions This is the largest study to date focusing on LBBB-CM following TAVI. LBBB-CM complicates about 9% of patients discharged with a new complete LBBB, occuring within a median follow-up of 40 [17-64] months. Electrocardiographic predictors for the development of LBBB-CM include prolonged QRS duration and PR interval at discharge. Closer follow-up may be required in this group of patients for timely diagnosis and intervention. Figure

Myocardial strain analysis by cardiac magnetic resonance associated with arrhythmias in repaired tetralogy of Fallot patients

BackgroundEvaluating myocardial function using cardiac magnetic resonance (CMR) feature tracking provides a comprehensive cardiac assessment, particularly a detailed evaluation for patients with repaired tetralogy of Fallot (rTOF). This study aimed to identify factors associated with arrhythmias in rTOF patients utilizing conventional CMR techniques, including myocardial strain measurements.MethodsThis single-center, retrospective study included 245 rTOF patients who underwent CMR between 2017 and 2023. Patients were stratified based on the presence or absence of arrhythmias during follow-up. The biventricular strain was assessed using CMR-derived feature tracking. Demographic, clinical, and imaging data were collected, and statistical analyses were performed to identify factors associated with arrhythmic events.ResultsThe median age at surgery was 5.6 years (range 1–44 years), with the median age at CMR was 27.5 years (range 15–69 years). Over the follow-up period, 25 patients (10.2%) experienced atrial or ventricular arrhythmias. Univariate analysis revealed significant associations between arrhythmic events and older age at surgery and CMR, lower functional class, larger heart size on chest radiograph, and prolonged QRS duration (QRSd). Additionally, arrhythmias were associated with increased right ventricular (RV) volume, reduced RV and left ventricular (LV) ejection fraction (EF), and impaired strain values. Multivariate binary logistic regression, adjusting for age at surgery, NYHA class, QRSd, and cardiothoracic ratio, identified that a lower RV EF (adjusted odds ratio [aOR] 6.97), RV global radial strain (GRS) (aOR 6.68), RV global circumferential strain (GCS) (aOR 6.36), RV global longitudinal strain (GLS) (aOR 3.14), and LV GRS (aOR 3.02) were all significantly associated with arrhythmias.ConclusionThis study highlights the significant contribution of CMR-derived myocardial strain measurements in predicting arrhythmic events in patients with rTOF. In addition to conventional RV EF, strain metrics—particularly those of the right ventricle- emerged as strong, independent predictors of arrhythmias, offering valuable prognostic information for clinical management in this patient population. These findings underscore the importance of myocardial strain analysis as a complementary tool to conventional imaging in evaluating arrhythmic risk in rTOF patients.Clinical trial numberNot applicable.

Mitochondrial Oxidative Stress and Cardiac Dysfunction in TERT Knockout Mice

Abstract Background Heart failure (HF) is a major cause of hospitalization in the elderly, with its incidence increasing due to aging and associated risk factors like hypertension, diabetes, and myocardial fibrosis. Aging-related myocardial fibrosis, characterized by alterations in the extracellular matrix and myocardial structure, impairs cardiac function. Mitochondrial oxidative stress plays a pivotal role in cardiac electrical and structural remodeling, necessitating a deeper understanding of its involvement in aging-related heart failure. Purpose The purpose of this study is to investigate the mechanisms of aging-related ventricular electrical and structural remodeling by constructing an aging mouse model. This research aims to provide potential therapeutic targets for heart failure associated with aging. Methods We developed a third-generation homozygous telomerase reverse transcriptase (TERT) knockout mouse model. Comparing third-generation homozygous TERT knockout mice (F3 group) with age-matched wild-type males (WT group). The study encompassed blood pressure measurement, electrocardiographic analysis, echocardiography, ELISA for cardiac biomarkers, ventricular tissue electrophysiology, fibrosis assessment through staining, transcriptomic profiling via RNA-seq, and electron microscopy of ventricular mitochondria. Results Compared to the WT group, the F3 group demonstrated increased P53 and P16 protein expression. Decreased LVEF and FS, along with increased interventricular septum thickness, left ventricular diameter, and left ventricular volume. Elevated serum NT-pro-BNP and troponin I (cTnI) levels, with prolonged QRS duration. Decreased left and right ventricular conduction velocity, accompanied by increased conduction dispersion. Notable elevation in COLI, TGFβ, and α-SMA gene transcription and protein expression in ventricular tissue. Significant differences in mitochondrial oxidative stress signal pathways via RNA-seq analysis. Elevated serum MDA levels and decreased SOD levels, with up-regulated Mn-SOD gene transcription and protein expression, and down-regulated MFN2 and Drp1 gene transcription and protein expression in ventricular tissue. Electron microscopy revealed mitochondrial abnormalities such as loose arrangement, decreased number, swelling, vacuolation, and myofilament disintegration or breakage in the F3 group. Conclusion Third-generation TERT-/- senescent mice exhibit notable cardiac impairments, including electrical remodeling, structural changes, and mitochondrial dysfunction. These findings suggest a potential link between mitochondrial oxidative stress and aging-related heart failure, indicating novel therapeutic opportunities targeting mitochondrial dysfunction for managing such conditions.

Effects of dapagliflozin according to QRS duration across the spectrum of LVEF: An analysis of DAPA-HF and DELIVER

Abstract Aims To document the prevalence of QRS prolongation in patients with HFrEF and HFmrEF/HFpEF, the association between QRS duration and outcomes, and the effect of dapagliflozin according to QRS duration across the spectrum of LVEF. Methods A pooled analysis of the DAPA-HF and DELIVER trials, excluding patients with a paced rhythm and CRT was conducted. The information collected was used to categorize patients according to QRS duration based on the cutpoints used in the CRT trials, as follows: QRS <120 ms, QRS 120-149 ms, and QRS ≥ 150 ms. The data were analyzed according to these categories and using QRS duration as a continuous variable. Results Overall, 4004 patients had HFrEF, and 5820 had HFmrEF/HFpEF. QRS duration (ms) was <120 in 7039 patients (71.7%), 120–149 in 1725 (17.6%), and ≥150 in 1060 patients (10.8%). The median follow-up time was 23 months. The rate of the primary composite outcome of CV death or worsening HF was 9.2 (95%CI 8.7-9.7), 14.3 (13.0-15.7), and 15.9 (14.1-17.9) per100 patient-years in the <120, 120–149, and ≥150 ms groups, respectively. This gradient in event rates was observed both in HFrEF and HFmrEF/HFpEF. Dapagliflozin, compared with placebo, reduced the risk of the primary outcome, consistently, across the QRS duration subgroups: hazard ratio (95% CI) 0.75 (0.67-0.85), 0.79 (0.65-0.96) and 0.89 (0.70-1.13) in the <120, 120–149, and ≥150 ms groups, respectively (P for interaction 0.28). The effect of dapagliflozin on the primary outcome was consistent across the QRS duration regardless of HF phenotype i.e., HFrEF or HFmrEF/HFpEF. Conclusion Prolongation of QRS duration is associated with worse outcomes irrespective of HF phenotype. Dapagliflozin reduced the risk of the primary outcome, regardless of QRS duration, in DAPA-HF and DELIVER.KM curves according to QRS durationEffect of dapagliflozin on outcomes

Electrical heart failure treatment in the Goldilocks zone: cardiac contractility modulation proves equally effective for heart failure control in HFrEF patients with mid-range QRS durations

Abstract Background Current guidelines recommend a four pillar therapy for heart failure with reduced ejection fraction (HFrEF). A subgroup of patients, namely those with a QRS duration (QRSd) ≥150 ms, may also qualify for cardiac resynchronization therapy. However, a 30% CRT non-responder rate persists, with patients with narrower QRSd (i.e., QRSd <150 ms) and non-left bundle branch block receiving less benefit. At present, cardiac contractility modulation (CCM) has only been established in patients with QRSd <120 ms. Given these limitations, new options for additional device therapy are urgently sought for those patients who face drug-refractory HFrEF and with intermediate QRSd of 120-149 ms. Purpose Primarily to evaluate the impact of CCM on HF-related hospitalizations and secondarily on left ventricular EF (LVEF) as well as quality of life (by Minnesota Living with Heart Failure Questionnaire (MLWHF) score and New York Heart Association (NYHA) class) in a real-world population of HFrEF patients with QRSd 120-149 ms, compared to QRSd <120 ms. Methods CCM-REG enrolled 503 HF patients receiving CCM with a follow-up of up to 2 yrs. HF-related hospitalization rates were available for 1 yr pre-implant. Safety was assessed by comparison of actual versus MAGGIC score predicted mortality. Results 455 patients were studied for these analyses. Among 111 subjects with QRSd 120-149 ms (mean QRSd 130±8 ms, age 68±10 yrs, 20% female, LVEF 29±9%, 82% NYHA class III), CCM diminished HF-related hospitalization rate by 72% (pre- vs. post-implant 0.90 vs. 0.25 events/per patient-yr over 2 yrs; p<0.001; Figure). LVEF improved by 7±8% (p=0.01 vs. baseline), MLWHFQ score by 10±23 pts (p=0.01 vs. baseline), and NYHA class by 0.5±0.7 classes (<0.001 vs. baseline). The effect size was similar to that in the QRSd <120 ms patients. Mortality within first year was 19% in QRSd 120-149 ms patients and thus not significantly different from the MAGGIC score prediction. Conclusions CCM significantly improved HF control in symptomatic HFrEF patients with moderately prolonged QRSd 120-149 ms. The effect was similar to patients with QRSd <120ms.Reduction in hospitalization rates

Multipoint pacing is associated with improved prognosis and cardiac resynchronization therapy response: MORE-CRT MPP randomized study secondary analyses.

Cardiac resynchronization therapy (CRT) via biventricular (BIV) pacing is indicated in patients with heart failure (HF), reduced ejection fraction, and prolonged QRS duration. Quadripolar leads and multipoint pacing (MPP) allow multiple left ventricle (LV) sites pacing. We aimed to assess the clinical benefit of MPP in patients who do not respond to standard BIV pacing. Overall, 3724 patients were treated with standard BIV pacing. After 6 months, 1639 patients were considered as CRT non-responders (echo-measured relative reduction in LV end-systolic volume (LVESV) < 15%) and randomized to MPP or BIV. We analysed 593 randomized patients (291 MPP, 302 BIV), who had BIV pacing >97% of the time before randomization and complete 12 months of clinical and echocardiographic data. The endpoint composed of freedom from cardiac death and HF hospitalizations and by LVESV relative reduction ≥15% between randomization and 12 months occurred more frequently in MPP [96/291 (33.0%)] vs. BIV [71/302 (23.5%), P = 0.0103], which was also confirmed at multivariate analysis (hazard ratio = 1.55, 95% confidence interval = 1.02-2.34, P = 0.0402 vs. BIV). HF hospitalizations occurred less frequently in MPP [14/291 (4.81%)] vs. BIV [29/302 (9.60%), incidence rate ratio = 50%, P = 0.0245]. Selecting patients with a large (>30 ms) dispersion of interventricular electrical delay among the four LV lead dipoles, reverse remodelling was more frequent in MPP [18/51 (35.3%)] vs. BIV [11/62 (17.7%), P = 0.0335]. In patients who do not respond to standard CRT despite the high BIV pacing percentage, MPP is associated with lower occurrence of HF hospitalizations and higher probability of reverse LV remodelling compared with BIV pacing.

Maternal hypertensive disorders of pregnancy and electrocardiographic findings among newborns: The Copenhagen Baby Heart Study.

Maternal preeclampsia is associated with both congenital heart defects and changes in left ventricular structure and function in the offspring. Whether preeclampsia and gestational hypertension also affect the offspring's cardiac conduction system is unknown. This study assesses whether infants exposed to maternal hypertensive disorders of pregnancy (HDPs) exhibit changes in their electrocardiogram (ECG) compared with infants unexposed to HDPs. This population-based cohort study included newborns from the Copenhagen Baby Heart Study who had an ECG performed within 30 days of birth and had available obstetric information. ECG parameters of newborns exposed to maternal HDPs were compared with those of unexposed newborns using linear regression. Our study cohort included 11,826 newborns, including 441 exposed to maternal preeclampsia and 320 exposed to gestational hypertension. Infants exposed to preeclampsia had prolonged QRS durations (adjusted mean difference 0.6 ms, 95% confidence interval [CI] 0.04, 1.16) and lower maximum amplitudes of the R-wave in V1 (adjusted mean difference, linear scale 0.95, 95% CI 0.90, 1.00), compared with unexposed infants. Exposure to maternal preeclampsia was not associated with changes in other ECG parameters. Exposure to gestational hypertension was associated with increased QT interval durations (QTc Bazett, adjusted mean difference 2.48 ms, 95% CI -0.23, 5.20; QTc Fridericia, adjusted mean difference 2.32 ms, 95% CI -0.19, 4.83). Our findings suggest that the newborn cardiac conduction system is affected by exposure to maternal preeclampsia. This could reflect the previously described thickening of the left ventricular myocardium in infants exposed to preeclampsia.

Delta QRS and outcomes post CRT in the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial

BackgroundFor patients with left ventricular systolic dysfunction and prolonged QRS duration, cardiac resynchronization therapy (CRT) can improve cardiac electromechanical synchrony and prevent adverse clinical outcomes. ObjectiveThis study sought to investigate the role of delta QRS duration (ΔQRSd) in predicting clinical response to CRT. MethodsThe RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure Trial) study randomized 1798 patients to CRT with defibrillator or implantable cardioverter-defibrillator alone. Those who received CRT and had electrocardiograms available at baseline and after CRT implantation were included in this analysis. ΔQRSd was calculated as the absolute difference between QRS duration at baseline and with CRT pacing. The primary outcome was the composite of death and heart failure hospitalization. ResultsThere were 813 patients included in this analysis. The median age was 67 years, and 125 patients (15.2%) were female. The median ΔQRSd was −2 ms (−20 to 18 ms), and 447 (55%) patients had a ΔQRSd ≤0 after implantation. ΔQRSd was an independent predictor of the composite outcome for patients with CRT (hazard ratio, 1.012; 95% confidence interval, 1.008–1.017). CRT recipients with ΔQRSd >0 had higher rates of the composite outcome than patients randomized to implantable cardioverter-defibrillator alone. ConclusionFor patients receiving CRT for heart failure with left ventricular systolic dysfunction and QRS prolongation, ΔQRSd was an independent predictor of long-term mortality and heart failure hospitalization.

Paced QRS Duration as the Major Determinant of Pacing Induced Cardiomyopathy in Complete AV Block

Patients with complete heart block often develop pacing-induced cardiomyopathy (PICM) after placement of a permanent pacemaker. Objective: To establish paced QRS duration as determinant of pacing induced cardiomyopathy in complete Atrioventricular (AV) block. Methods: This descriptive study included 115 male and female patients that had a permanent pacemaker implanted for complete AV block, at the department of Cardiology, Hayatabad Medical Complex, Peshawar, during the period 1st November 2023 till 30th June 2024. Patients were evaluated for the presence of PICM and subsequently grouped as PICM and non-PICM. Paced QRS duration in both groups was compared. Results: PICM was confirmed in 63 patients (54.8%) and 52 (45.2%) were non-PICM. Mean age in PICM group was 71.2 ± 8.7 years and 66.8 ± 9.5 years in non-PICM group. The mean paced QRS duration in PICM group was 200.5 ± 22.3 milliseconds and 168.3 ± 15.7milliseconds in non-PICM group (p value &lt;0.001). Conclusion: Prolonged paced QRS duration was found as key indicator for predicting pacing induced cardiomyopathy in patients with permanent pacing for complete AV block.

Clinical, electrocardiographic, and diagnostic imaging features and outcomes in cats with electrocardiographic diagnosis of ventricular pre-excitation: a retrospective study of 23 cases (2010–2022)

Introduction/ObjectivesVentricular pre-excitation (VPE) occurs when atrial electrical impulses prematurely excite the ventricles through an aberrant muscle bundle known as an accessory pathway (AP). Orthodromic atrioventricular reciprocating tachycardia is a re-entrant, narrow complex supraventricular tachycardia (SVT), maintained through retrograde conduction over an AP. The study aimed to describe patient signalments, clinical signs, electrocardiographic (ECG) and diagnostic imaging features, treatments, prognostic variables, and outcomes in cats with ECG diagnosis of VPE. AnimalsTwenty-three cats diagnosed with VPE between January 2010 and August 2022 were included in this study. Materials and MethodsThis was a multicenter, retrospective study with twenty-three cats diagnosed with VPE between January 2010 and August 2022. Ventricular pre-excitation diagnosis was based on ECG evidence of shortened PR interval, delta wave, and prolonged QRS duration. The median survival time (MST) was estimated by the Kaplan-Meier curve. Log-rank tests were performed to assess for an association between clinical signs or presence of structural heart disease on the MST. ResultsFourteen (60.8%) cats with VPE also had SVT documented on ECG, with 7 of 14 with ECG confirmation of orthodromic atrioventricular reciprocating tachycardia. Four (17.4%) cats had suspected AP-mediated tachyarrhythmia based on associated clinical signs. Common presenting signs included collapse (15/23; 65.2%) and respiratory distress (14/23; 60.8%). Five (21.7%) cats were asymptomatic. Heart rate during SVT ranged from 310 to 420 bpm (median: 375 bpm). Initial treatment included atenolol (10/18), sotalol (5/18), diltiazem (2/18), and amiodarone (1/18). From the date of diagnosis, MST was 1872 days (5.1 years). ConclusionsThe majority of cats with VPE also had symptomatic SVT. The prognosis for cats with VPE is considered good with an MST of greater than five years.

Evaluation of electrocardiographic criteria for predicting left ventricular hypertrophy and dilation in presence of left bundle branch block

BackgroundThe utility of standard published electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) in patients with left bundle branch block (LBBB) is not established. We have previously shown that in ECGs demonstrating LBBB, QRS duration outperforms vectorcardiographic X, Y, Z lead and root-mean-squared (3D) amplitudes and voltage-time-integrals in diagnosing LVH and dilation. We sought to evaluate diagnostic yields of published LVH criteria versus QRS duration for ECG based diagnosis of LVH and dilation in presence of LBBB. MethodsWe included adult patients with typical LBBB having ECG and transthoracic echocardiogram performed within 3 months of each other in 2010–2020. We obtained area under receiver-operator characteristic curve (AUC) for QRS duration and each of the published ECG LVH criteria to predict increased LV mass indexed (↑LVMi, women >95 g/m2, men >115 g/m2) and LV end diastolic volume indexed (↑LVEDVi, women >61 mL/m2, men >74 mL/m2). ResultsAmong 413 adults (53 % women, age 73 ± 12 yr) with LBBB, the traditional LVH criteria performed poorly to detect ↑LVMi or ↑LVEDVi. Cornell voltage-duration product had the highest AUCs (↑LVMi 0.634, ↑LVEDVi 0.580). QRS duration had a higher AUC for diagnosing ↑LVMi (women 0.657, men 0.703) and ↑LVEDVi (women 0.668, men 0.699) compared to any other criteria. ConclusionsIn patients with LBBB, prolonged QRS duration (women ≥150 ms, men ≥160 ms) is a superior predictor of LVH and dilation than traditional ECG-based LVH criteria.

Effects of dapagliflozin according to QRS duration across the spectrum of left ventricular ejection fraction: An analysis of DAPA-HF and DELIVER.

The primary aim was to evaluate the effect of dapagliflozin according to QRS duration across the spectrum of left ventricular ejection fraction (LVEF), given that prolongation of QRS duration is associated with less favourable ventricular remodelling with pharmacological therapy and worse outcomes. A pooled analysis of the DAPA-HF and DELIVER trials, excluding patients with a paced rhythm and cardiac resynchronization therapy. Overall, 4008 patients had heart failure (HF) with reduced ejection fraction (HFrEF), and 5816 had HF with mildly reduced/preserved ejection fraction (HFmrEF/HFpEF). QRS duration was <120 ms in 7039 patients (71.7%), 120-149 ms in 1725 (17.6%), and ≥150 ms in 1060 patients (10.8%). The median follow-up time was 23 months. The rate of the primary composite outcome of cardiovascular death or worsening HF was 9.2 (95% confidence interval [CI] 8.7-9.7), 14.3 (13.0-15.7), and 15.9 (14.1-17.9) per 100 patient-years in the <120, 120-149, and ≥150 ms groups, respectively. This gradient in event rates was observed both in HFrEF and HFmrEF/HFpEF. Dapagliflozin, compared with placebo, reduced the risk of the primary outcome consistently across the QRS duration subgroups (hazard ratio [95% CI] 0.75 [0.67-0.85], 0.79 [0.65-0.96], and 0.89 [0.70-1.13] in the <120, 120-149, and ≥150 ms groups, respectively; p for interaction = 0.28). The effect of dapagliflozin on the primary outcome was consistent across the QRS duration regardless of HF phenotype that is, HFrEF or HFmrEF/HFpEF. Prolongation of QRS duration is associated with worse outcomes irrespective of HF phenotype. Dapagliflozin reduced the risk of the primary outcome, regardless of QRS duration, in DAPA-HF and DELIVER.

Mechanical dyssynchrony as a selection criterion for cardiac resynchronization therapy: Design of the AMEND-CRT trial.

One third of patients do not improve after cardiac resynchronization therapy (CRT). Septal flash (SF) and apical rocking (ApRock) are deformation patterns observed on echocardiography in most patients eligible for CRT. These markers of mechanical dyssynchrony have been associated to improved outcome after CRT in observational studies and may be useful to better select patients. The aim of this trial is to investigate whether the current guideline criteria for selecting patients for CRT should be modified and include SF and ApRock to improve therapy success rate, reduce excessive costs and prevent exposure to device-related complications in patients who would not benefit from CRT. The AMEND-CRT trial is a multicentre, randomized, parallel-group, double-blind, sham-controlled trial with a non-inferiority design. The trial will include 578 patients scheduled for CRT according to the 2021 ESC guidelines who satisfy all inclusion criteria. The randomization is performed 1:1 to an active control arm ('guideline arm') or an experimental arm ('echo arm'). All participants receive a device, but in the echo arm, CRT is activated only when SF or ApRock or both are present. The outcome of both arms will be compared after 1year. The primary outcome measures are the average change in left ventricular end-systolic volume and patient outcome assessed using a modified Packer Clinical Composite Score. The findings of this trial will redefine the role of echocardiography in CRT and potentially determine which patients with heart failure and a prolonged QRS duration should receive CRT, especially in patients who currently have a class IIa or class IIb recommendation.

The Effect of Obesity on Repolarization and Other ECG Parameters.

Background: Overweight and obesity are important risk factors in the development of cardiovascular diseases. New repolarization markers, such as the Tpeak-Tend interval and JTpeak intervals, have not yet been profoundly studied in obese patients. The study aims to analyze whether, in patients with obesity and overweight, repolarization markers, including the Tpeak-Tend interval, are prolonged and simultaneously check the frequency of other ECG pathologies in a 12-lead ECG in this group of patients. Methods: A study group consisted of 181 adults (90 females and 91 males) with overweight and first-class obesity. The participants completed a questionnaire, and the ECG was performed and analyzed. Results: When analyzing the classic markers, only QT dispersion was significantly higher in obese people. The Tpeak-Tend parameter (97.08 ms ± 23.38 vs. 89.74 ms ± 12.88, respectively), its dispersion, and JTpeak-JTend parameters were statistically significantly longer in the obese group than in the controls. There were also substantial differences in P-wave, QRS duration, and P-wave dispersion, which were the highest in obese people. Tpeak-Tend was positively correlated with body mass and waist circumference, while JTpeak was with BMI, hip circumference, and WHR. Tpeak/JT was positively correlated with WHR and BMI. In backward stepwise multiple regression analysis for JTpeak-WHR, type 2 diabetes and smoking had the highest statistical significance. Conclusions: Only selected repolarization markers are significantly prolonged in patients with class 1 obesity and, additionally, in this group, we identified more pathologies of P wave as well as prolonged QRS duration.

The causal relationship between sarcopenia-related traits and ECG indices - A mendelian randomization study

BackgroundSarcopenia is a common geriatric condition closely associated with cardiovascular diseases and other health issues. This study aims to investigate the causal relationship between sarcopenia-related traits and electrocardiogram(ECG) indices. MethodsWe conducted a comprehensive analysis utilizing summary data from genome-wide association studies (GWAS) associated with sarcopenia-related traits, including hand grip strength, lean body mass, and walking pace. ECG indices included PR interval, PP interval, ST duration, QRS duration and T wave duration. The primary analytical method employed was the inverse variance-weighted method (IVW). ResultsAccording to our study findings, we identified a significant association between sarcopenia-related traits and ECG indices. Specifically, we observed a positive correlation between increased muscle mass and certain ECG indices. For instance, increased limb muscle mass (including left arm, right arm, left leg, and right leg) was associated with prolonged PR interval and QRS duration. This suggests that enhancing muscle mass may impact the timing of cardiac electrical activity. Additionally, increased whole-body fat-free mass showed similar associations with cardiac electrical activity. ConclusionSarcopenia-related traits have a unidirectional causal relationship with ECG indices, indicating that sarcopenia affects cardiac electrical activity.

Effectiveness of dynamic atrioventricular optimization during patient exercise in cardiac resynchronization therapy

Abstract Background Cardiac resynchronization therapy (CRT) is considered the standard treatment for patients with heart failure and prolonged QRS duration. Recent studies suggest that atrioventricular delay (AVD) optimization can play a key role in QRS narrowing, thus improving CRT outcomes. For this purpose, device-based algorithms have been developed. In particular, the SyncAV algorithm continuously monitors the patient’s intrinsic AVD and dynamically adjusts the pacing AVD to allow fusion of the left ventricle pacing with intrinsic right ventricle depolarization. SyncAV optimization is usually performed in a single patient condition, i.e. at rest, and in a single operating scenario of the device, i.e. during atrial sensing. Purpose This study aims to compare QRS narrowing after AVD optimization using SyncAV in CRT-treated patients at rest, during moderate exertion, and during an increase in the atrial pacing rate. Methods This is a prospective, non-randomized, non-blinded, multicenter study. The study population consisted of patients in sinus rhythm, PR interval &amp;lt; 350 ms, and rest ventricular rate &amp;lt; 100 bpm. Within one month from the implant, patients were assessed for AVD optimization with SyncAV, selecting the offset (i.e. 10 to 40% AVD) that resulted in the shortest QRS duration (QRSd). Subsequently, patients performed moderate physical activity using a bicycle ergo-meter while a surface ECG was collected. QRSd was assessed once patients achieved a heart rate over 20 bpm to baseline heart rate, up to 100 bpm. Finally, QRSd narrowing was evaluated during a programmed increase in atrial pacing (i.e. &amp;gt;20 bpm of baseline atrial rate). Results Nine patients were treated with CRT and enrolled (age 67,3 ± 13,2 years; 66% male; LV ejection fraction 33,7±2,9 %; intrinsic QRSd 155,6 ± 12,7 ms) with intact atrioventricular conduction (PR interval 170,6±25,8 ms). The median SyncAV offset that provided the best QRSd reduction was 20 % (10 - 35%). Intrinsic QRSd was reduced to 132,7 ± 10,0 ms (-14,2±9,4%) with standard biventricular pacing and to 122,0 ± 11,2 ms (-21,2±8,5%) with SyncAV optimization. During exercise the mean heart rate was 88,1 bpm, the QRSd was reduced to 132,7 ± 10,0 ms (-14,2±9,4%) with standard biventricular pacing and to 124,9 ± 14,9 ms (-19,3±10,8 %) with SyncAV optimization. The mean heart rate during atrial pacing was 90 bpm with paced QRSd of 126,0 ±13,9 ms (-18,9±7,3% from baseline) with SyncAV optimization and paced PR interval of 198,2±22,7ms. Conclusion We evaluated the effectiveness of SyncAV for AVD optimization in out-of-clinic. This study demonstrates the possibility of narrowing the QRSd using SyncAV at several activity levels. Nevertheless, a deeper evaluation is needed to confirm our findings, investigating the SyncAV role in a larger population of patients.

Retrograde Conduction in Left Bundle Branch Block: Insights From Left Bundle Branch Pacing.

Biventricular pacing is a well-established therapy for patients with heart failure (HF), left bundle branch block (LBBB) and left ventricular (LV) dysfunction. Left bundle branch pacing (LBBP) has emerged as an alternative to biventricular pacing. The aim of this study was to assess the retrograde conduction properties of the left bundle branch in patients with nonischemic cardiomyopathy and LBBB during LBBP and its clinical implications. Patients undergoing successful LBBP for nonischemic cardiomyopathy with LV ejection fraction (LVEF)≤35% and LBBB were included. Continuous recording of His potential was performed using a quadripolar catheter. Unidirectional block was defined as retrograde His bundle activation during LBBP with stimulus to His potential (SH) duration less than or equal to antegrade HV interval and bidirectional block as VH dissociation or SH duration greater than HV interval. HF hospitalization, ventricular arrhythmias, and mortality were documented. A total of 165 patients were included. The mean follow-up duration was 21.8 ± 13.1months. Bidirectional block (group I) was observed in 82% (n=136), and these patients were noted to have advanced HF stage and prolonged baseline QRS duration. Unidirectional block (group II) with intact retrograde conduction was observed in 18% (n=29) and was associated with narrow paced QRS duration and higher LVEF during follow-up. Super-response (LVEF≥50%) was observed in 54.4% (n=74) in group I compared with 73.3% (n=22) in group II (P=0.03). The OR for LVEF normalization was 4.1 (95%CI: 1.26-13.97; P=0.02), with unidirectional block compared with bidirectional block in patients with LBBB and LV dysfunction. Adverse clinical outcomes as measured by a composite of HF hospitalization, ventricular arrhythmias, and mortality were significantly higher in group I compared with group II (12.5% vs 0%; P=0.04). Bidirectional block in LBBB was characterized by advanced HF symptoms, while unidirectional block was associated with better clinical outcomes after cardiac resynchronization therapy by LBBP.

The Association Between Components of Metabolic Syndrome and Abnormal Electrocardiograms in the Saudi Population: A Retrospective Study.

Saudi Arabia has a high metabolic syndrome (MetS) prevalence. Having MetS increases the risk of cardiovascular disease (CVD), CVD mortality, and myocardial infarction (MI). There is a lack of information regarding MetS and electrocardiogram (ECG) abnormalities in Saudi Arabian populations. Further, it is unclear to what extent MetS components are associated with abnormal ECGs in Saudi populations. We investigated whether ECG abnormalities and MetS are associated with Saudi adults. Furthermore, we assessed the relationship between ECG abnormalities and the components of MetS based on the age and gender of the individuals. Materials and methods: A retrospective study was conducted at Dr Soliman Fakeeh Hospital in Jeddah, Saudi Arabia, on 208 patients with MetS. Participants' clinical and laboratory data were examined. A detailed analysis of the ECG was performed. ECG abnormalities were divided into minor and major abnormalities based on Novacode criteria. In addition to ischemic ECG findings, the ECG showed prolonged PR intervals, prolonged P duration, prolonged QRS duration, and prolonged QTc intervals. Results: One hundred and thirty-seven participants (65.9%) had elevated fasting blood glucose (FBS), 129 had central obesity (62%), 93 had high blood pressure (BP) (44.7%), 74 had elevated triglycerides (35.6%), and 49 had low high-density lipoprotein (23.6%).An abnormal ECG was found in 86 (41.3%) participants. It consisted of ischemic ECGs, atrioventricular (AV) block (first and second degrees), bundle branch block (right bundle branch block [RBBB], left bundle branch block [LBBB], RBBB with left anterior hemiblock, RBBB with right anterior hemiblock), arrhythmias (premature ventricular contractions [PVCs], premature atrial complexes [PACs], atrial fibrillation [AF], sinus bradycardia, sinus arrhythmia), prolonged QTc, prolonged PR interval, and prolonged QRS duration. There were 29 (13.9%) cases with multiple ECG abnormalities, 57 (27.4%) had one abnormal ECG, 42 (20.2%) had minor abnormal ECGs, and 44 (21.2%) had major abnormal ECGs. Middle-aged and elderly males accounted for the majority of these ECG changes. In the central obesity group, 22 participants (10.6%) had ischemic ECGs, 18 (8.7%) had prolonged QTc, 10 (4.8%) had first-degreeAV block, 6 (2.9%) had sinus bradycardia, 7 (3.4%) had RBBB, 4 (1.9%) had LBBB, 3 (1.4%) had PVCs, 2 (1%) had ventricular preexcitation, and one (0.5%) had PACs. An elevated FBS group included 19 participants (9.1%) with an ischemic ECG, 18 (8.7%) with a prolonged QTc, 11 (5.3%) with a first-degreeAV block, 9 (4.3%) with sinus bradycardia, 6 (2.9%) with slight ST-T abnormality, 5 (2.4%) with RBBB, and 5 (2.4%) with LBBB. Finally, one (0.5%) of these patients had second-degreeAV block, RBBB with left anterior hemiblock, left anterior hemiblock, PVCs, AF, ventricular preexcitation, and sinus arrhythmia for each. Saudi Arabian populations with MetS were strongly associated with abnormal ECG findings, particularly ischemic ECG findings, AV block (firstand second degrees), and BBB (RBBB, LBBB). Middle-aged and elderly males accounted for the majority of these ECG changes. The most important factors contributing to ECG changes were elevated FBS and central obesity.

CMR feature tracking–based left atrial mechanics predicts response to cardiac resynchronization therapy and adverse outcomes

BackgroundCardiac resynchronization therapy (CRT) is an established therapy for advanced heart failure (HF) with prolonged QRS duration. However, 30% of patients have shown no benefit from the treatment. ObjectiveThis study aimed to examine the value of left atrial (LA) mechanics by cardiac magnetic resonance (CMR) to predict response to CRT and clinical outcomes. MethodsA total of 163 CRT recipients with preimplantation CMR examination were retrospectively recruited. CMR feature tracking was used to evaluate LA size and function. The end points include (1) improvement of at least 5% in left ventricular ejection fraction combined with a reduction of at least 1 New York Heart Association functional class at 6-month follow-up and (2) any all-cause death or HF hospitalization during follow-up. ResultsOverall, 82 (50.3%) were CRT responders. CRT nonresponders had larger LA and worse LA reservoir and booster pump function than did responders (P < .001 for all). LA structural (maximum volume index < 47 mL/m2) and functional (booster pump strain > 8.5%) criteria were incremental to traditional indicators in detecting CRT response (χ2, 40.83 vs 9.98; P < .001). During follow-up (median 41 months), survival free from death or HF hospitalization increased with the number of positive LA criteria (log-rank, P < .001). After adjustment for clinical confounders, the absence of the 2 criteria remained associated with a considerably increased risk of death or HF hospitalization (adjusted hazard ratio 6.2; 95% confidence interval 2.15–17.88; P = .001). ConclusionThe preprocedure LA mechanics evaluated using CMR may be useful to predict response to CRT and improve risk stratification in CRT recipients.

Utility of electrocardiogram to predict the occurrence of the no-reflow phenomenon in patients undergoing primary percutaneous coronary intervention (PPCI): a systematic review and meta-analysis.

The no-reflow phenomenon affects about one out of five patients undergoing Primary Percutaneous Coronary Intervention (PPCI). As the prolonged no-reflow phenomenon is linked with unfavorable outcomes, making early recognition is crucial for effective management and improved clinical outcomes in these patients. Our review study aimed to determine whether electrocardiogram (ECG) findings before PCI could serve as predictors for the occurrence of the no-reflow phenomenon. We systematically searched MEDLINE, Scopus, and Embase to identify relevant studies. The random-effect model using inverse variance and Mantel-Haenszel methods were used to pool the standardized mean differences (SMD) and odds ratios (OR), respectively. Sixteen eligible articles (1,473 cases and 4,264 controls) were included in this study. Based on our meta-analysis of baseline ECG findings, the no-reflow group compared to the control group significantly had a higher frequency of fragmented QRS complexes (fQRS) (OR (95% CI): 1.35 (0.32-2.38), P-value = 0.01), and Q-waves (OR (95% CI): 1.97 (1.01-2.94), P-value <0.001). Also, a longer QRS duration (QRSD) (SMD (95% CI): 0.72 (0.21, 1.23), p-value <0.001) and R wave peak time (RWPT) (SMD (95% CI): 1.36 (0.8, 1.93), P < 0.001) were seen in the no-reflow group. The two groups had no significant difference regarding P wave peak time (PWPT), and P wave maximum duration (Pmax) on baseline ECG. Our findings suggest that prolonged QRSD, delayed RWPT, higher fQRS prevalence, and the presence of a Q wave on baseline ECG may predict the occurrence of the no-reflow phenomenon in patients undergoing PPCI.