Intraventricular Conduction Delay Research Articles

Left bundle branch area pacing optimized cardiac resynchronization therapy (LOT CRT) -comparative results to a CRT implanted patient population

Abstract Background Cardiac resynchronization therapy (CRT) is gold standard treatment option among patients with symptomatic heart failure with reduced left ventricular ejection fraction (LVEF) and intraventricular conduction delay of left bundle branch block (LBBB) morphology. Purpose Left bundle branch area pacing optimized cardiac resynchronization therapy (LOT CRT) is a novel and promising approach for CRT candidate patients even in advanced intraventricular conduction delay, however convincing follow-up data regarding this patient group is still lacking. Methods In our observational registry 35 LOT CRT vs. 35 conventional CRT patients were consecutively implanted according to current guidelines. All the patients had LBBB morphology QRS width of >150 ms. The two compared patient group did not show significant difference in age, gender, baseline non-ischemic etiology, LVEF, NYHA functional class, LBBB QRS width. Results Immediate postoperative results showed significantly increased QRS width reduction (p=.028) and at 6 months of follow-up a significantly greater improvement in LVEF(p=.031), NYHA functional class (p=.04) and Nt-ProBNP levels (p=0.043) were seen in LOT CRT patient group compared to conventional CRT patients. Conclusion Our single center observational study showed significant improvement in prompt postoperative QRS width and clinical follow-up parameters in LOT CRT implanted patients compared to conventional CRT implanted patients.LOTCRTvs.CRTQRSwidthreductionLOTCRTXray

Impact of non-typical LBBB on CRT response

Abstract Introduction Cardiac resynchronization therapy (CRT) benefits have been established in patients with heart failure and reduced left ventricular ejection fraction (HFrEF) who have a broad QRS and remain symptomatic despite optimized medical therapy. Responders typically are female, with LBBB and broader QRS. It remains uncertain to what extent do patients with non-LBBB QRS complex morphology respond to CRT and also if there are differences among various types of intraventricular conduction delays. Purpose To evaluate the impact of non-typical left bundle branch block (LBBB) on reverser remodeling and clinical events. Methods Single center, observational, retrospective study including patients (pts) who implanted CRT in the context of HFrEF, from 2015 to 2020. Evaluation of QRS morphology analysis was conducted. CRT response was defined by a reduction of LVESV≥15% or an increase in LVEF≥10%. Predictors of CRT response were evaluated with Chi-square and Mann- Whitney analysis. Impact on reverse remodeling and clinical outcomes was performed with Kaplan-Meyer analysis. Results A total of 361 pts were included for analysis, of which 184 had non-typical LBBB. Pts had a mean age of 71±9years old, the majority of pts were female (61%), and almost half were ischemic (47.8%). EGC evaluation prior to CRT implantation, revealed an atypical LBBB in 83 (45.1%) pts, typical RBBB in 23 (12.5%) pts, atypical RBBB 94.(9%) pts and nonspecific intraventricular conduction delay in 69 (37.5%) pts. During a mean time of follow-up of 2.9 ±2.4years, 33 pts (18%) had hospitalizations due to HF and 68 (37%) died. In this cohort, 78 pts (42.4%) were deemed as responders, who presented a better clinical outcome when compared to non-responders (p < 0.001, HR 2.629 [95% CI 1.635-4.225]. There was no difference among the four types of intraventricular conduction analyzed in respect to degree of CRT response – figure 1. Regarding clinical events during follow-up, there was once again no significant difference among the different patterns of non-typical LBBB– figure 2. In this subset population we found no independent predictors of CRT response, although non-responders were significantly older than responders (72±8 vs 69±10 years-old (p=0.016). Conclusion Although pts with non-typical LBBB morphology display a lower therapy response to CRT than reported for LBBB pts, the rate of response is not negligible and represents a protective factor for clinical outcomes. Different types of intraventricular conduction delay present no difference regarding long- term prognosis or reverse remodeling.Survival according to CRT response

AI-based heart monitoring: the FIFPRO player pilot study

Abstract Background The implementation of remote global heart screening and monitoring services in professional players is essential as it allows: (1) efficient and rapid identification of cardiac abnormalities ensuring their safety and health; (2) standardizing the quality of medical heart checkups in low-resource regions to promote health equity; (3) prioritizing diversity in data collection to aid in the research and prevention of sudden cardiac death in sports. Purpose To demonstrate the feasibility of a global standardized heart screening program for professional footballers by leveraging an artificial intelligence platform to efficiently identify cardiac patterns from Holter’s records. In this study, we presented the most prevalent cardiac patterns, the patterns that prompted further assessment by the cardiologist, and an example of a typical research question exploring the effect of age on the prevalence of cardiac patterns. Methods The pilot study included 100 players from 9 different countries: Australia, Botswana, Bulgaria, Ghana, Greece, Indonesia, Panama, Spain and the UK. Holter data (Bittium Faros 180) were acquired in real-life monitoring from 24h to 48h including training sessions. Electrocardiograms were analyzed through an AI platform with a deep learning-based methodology to detect over 20 cardiac patterns. Medical team reviewed labels of detected cardiac patterns to validate and further train the AI algorithm. Thereafter cardiologists reviewed the cardiac patterns to determine whether further cardiac assessment was required. Results 145 sessions were recorded, with 100 players having one session and 45 players having two sessions. The mean age was 27.5 years (minimum 15, maximum 41), with 31 female players. The median duration of the Holter session was 25.1 hours. Table 1 presents the most frequently detected cardiac patterns: low density premature atrial complex, mild sinus bradycardia and low density premature ventricular complex in over 50% of the players. 18 players were identified with abnormalities requiring further study. 14 presented altered cardiac patterns (6 with negative T-waves, 5 with intraventricular conduction delay, 2 with QRS low voltage and 1 with P wave enlargement) and 3 presented premature ventricular complexes during exercise or high density. 1 was excluded because of inadequate clinical information. Regarding the effect of age, players with mild sinus bradycardia, premature ventricular complex, pause (2-3 seconds) or 2-degree atrioventricular block were found to be significantly older than players without those patterns (Figure 1). Conclusion This is the first global AI-based platform to obtain standardized heart screening program in professional athletes remotely. This study has been validated using diverse data from groups on 5 continents. This approach is beneficial to promote health equity in screening and monitoring of possible cardiomyopathies and channelopathies in order to prevent sudden cardiac death.Table 1Figure 1

Implant failure predictors of left bundle branch pacing used as cardiac resynchronization therapy: importance of left ventricular diameter and QRS morphology

Abstract Background Left bundle branch pacing (LBBP) is considered an alternative to cardiac resynchronization therapy (CRT). However, LBBP is not suitable for all heart failure patients. Purpose The aim of our study was to identify predictors of unsuccessful LBBP implantation in CRT candidates. Methods A cohort of consecutive patients with indications for CRT were included. Clinical, echocardiography and electrocardiographic variables were prospectively recorded. Results A total of 157 patients were included in the analysis. The LBBP implant was successful in 129/157 (82.2%) patients, and the implant failed in 28/157 patients (17.8%). The causes of failed implantation were as follows: unsatisfactory paced QRS (21/28; 75%); impossibility of screwing the helix (4/28; 14.3%); lead instability (2/28; 7.1%); and high pacing thresholds (1/28; 3.6%). Left ventricular end diastolic diameter (LVEDD), nonspecific intraventricular conduction delay morphology (IVCD), and QRS width were predictors of failed implants according to the univariate analysis. In a multivariable regression analysis, LVEDD [OR 1.44 per 5 mm increase (95% CI 1.13, 1.82) p=0.003] and IVCD [OR 2.96 (95% CI 0.74, 11.84) p=0.09] were independent predictors of unsuccessful LBBP implantation. An LVEDD of 60 mm has 75% sensitivity and 67% specificity to predict LBBP implant failure. Conclusions When LBBP was used as CRT, LVEDD and IVCD predicted unsuccessful implantation. IVCD triples the possibility of failed implantation independently of LVEDD. Caution should be exercised when considering these parameters to plan the best pacing strategy in patients.

Gender matters. Impact of gender on the utilization of defibrillators with cardiac resynchronisation therapy and outcome: results from the German DEVICE registry

Abstract Background Defibrillators with cardiac resynchronisation therapy (CRT-Ds) are widely used in patients with left ventricular (LV) systolic dysfunction and high-grade intraventricular conduction delays. Real world data regarding the impact of gender on CRT-D implantation and outcome are scarce. Purpose To determine the impact of gender on the CRT-D devices implantation and outcome. Methods The German DEVICE registry is a prospective, nationwide database of ICD and CRT devices implantations and revisions. A total of 1536 patients undergoing CRT-D implantations and revisions were included between March 2007 and February 2014 in 44 centres and monitored for a median of 17.2 months. Herein we conducted the gender-based analysis of the CRT-D recipients. Results Only a minority of the patients in this registry was females (329; 21,4%). The demographic data (age and BMI) were similar between genders. The female population was less likely to have a coronary artery disease (35.3% vs. 56.7%; p<0.001), but more likely to have dilated cardiomyopathy (61.1% vs. 49.5%; p<0.001). Significantly less women had a LVEF ≤ 35% (90.6% vs. 94.8%, p=0.005). A total of 84.2% of females and 80.2% of males received a device for the primary prevention of sudden cardiac death (SCD; p=0.10). Women were more likely to have a history of ventricular fibrillation (44.2% vs. 23.0%, p=0.002) and resuscitation (p=0.01), but less likely to have a history of ventricular tachycardia (44.2% vs. 61.9%; p=0.019). Significantly more women than men showed a left bundle branch block at implantation (89.7% vs. 80.9%, p<0.001). A QRS duration of at ≥ 150 ms was noted in 74.8% of women and 71.5% of men (p=0.25), while significantly more women had a QRS of ≥ 120 ms (97.0% vs. 94.2%; p=0.043). The overall incidence of major periprocedural complications and in hospital complications was similar between groups (3.6% vs 2.4%, p=0.25 and 6.0% vs. 5.8%, p=0.88 respectively), however a pneumothorax requiring intervention was more common among women (1.8% vs. 0.5%, p=0.027). The rate of device revision until discharge and the in-hospital mortality did not differ between genders. The Kaplan-Meier estimated 1-year all-cause mortality was 6.3% for women and 8.2% for men (p=0.25, Fig.1), while the estimated incidence of death or defibrillator shocks was 11.0% and 15.1%, respectively (p=0.051). The non-lethal complications and device revisions during follow-up (FU) were similar between genders. Women showed a lower non-device-dependent cardiovascular hospitalisation rate (8.2% vs. 13.1%; p=0.043) and had more fear of receiving a device shock than men (p=0.002). Conclusions In this real-life CRT-D patient cohort only a minority of patients were females. Women had a higher rate of pneumothorax requiring intervention. The 1-year mortality and the complications during FU were similar between genders. Women had a lower rate of non-device-dependent cardiovascular hospitalisation during FU.Fig.1. Kaplan-Meier estimated survival.

A RARE CASE OF INTERVENTRICULAR SEPTUM DUPLICATION

Abstract Case Report A 62–year–old man, history of hypertension. In 2015, there was suspicion of non–compaction cardiomyopathy, and he underwent cardiac MRI at another facility (report not available). The patient reported palpitations and dyspnea with exertion, leading to a follow–up visit. EKG showed sinus rhythm 90/min, nonspecific intraventricular conduction delay and isolated monomorphic ventricular ectopic beats. Echo revealed a mildly dilated left ventricle (end–diastolic volume 88 ml/m), systolic function at the lower limits of normal (EF 53%), and prominent muscular structures near the posterior interventricular septum (SIV), likely related to anomalies of the papillary muscles (prominent and possibly duplicated posterior–medial papillary muscle). There was apical trabecular protrusion, which did not meet the criteria for non–compaction (NC/C ratio in systole approximately 1), with no other significant findings. The cardiac MRI, performed to assess dilated cardiomyopathy, revealed a conspicuous structural abnormality in the septo–papillary region, located medio–apically and paraseptal–endocardial in the left ventricle. This anomaly lacked evident chordae tendineae with the mitral valve leaflets and exhibited synchronous systo–diastolic motion with the left ventricular wall, suggesting septal duplication. The septal thickness was slightly reduced, particularly in the medio–apical region. Additionally, there was hypertrabeculation of the posterior and lateral walls of the left ventricle, exceeding the threshold for non–compaction (NC/C ratio in end–diastole: 2.6 – normal range: <2.3). Left ventricular mass was normal (mass: 173.52 g; mass/body surface area (BSA): 86.58 g/m). Basal septum, medio–apical septum and medio–apical lateral wallshowed hypokinetic contractility. The left ventricle was dilated (end–diastolic diameter: 55.0 mm; end–systolic diameter: 45.3 mm – end–diastolic volume: 230 ml; stroke volume/BSA: 57.6 ml/m² – EF: 51%). Areas of late gadolinium enhancement (LGE) were observed in the anterior medio–basal septum and at the site of the described structural muscular anomaly, both displaying an intramural non–ischemic pattern. Conclusions The described findings suggest a picture of dilated cardiomyopathy and an associated structural septo–papillary anomaly of uncertain diagnostic interpretation (septum duplication with associated non–compacted myocardium? duplicated posterior–medial papillary muscle with associated non–compacted myocardium?).

Pseudo precordial ST-segment depression

We present a case with acute coronary syndrome and very unusual QRS widening in the acute phase. The case highlights that non-specific intraventricular conduction delay should be considered as a high risk ECG pattern predicting poor prognosis.

A Revised Definition of Left Bundle Branch Block Using Time to Notch in Lead I

Current left bundle branch block (LBBB) criteria are based on animal experiments or mathematical models of cardiac tissue conduction and may misclassify patients. Improved criteria would impact referral decisions and device type for cardiac resynchronization therapy. To develop a simple new criterion for LBBB based on electrophysiological studies of human patients, and then to validate this criterion in an independent population. In this diagnostic study, the derivation cohort was from a single-center, prospective study of patients undergoing electrophysiological study from March 2016 through November 2019. The validation cohort was assembled by retrospectively reviewing medical records for patients from the same center who underwent transcatheter aortic valve replacement (TAVR) from October 2015 through May 2022. Patients were classified as having LBBB or intraventricular conduction delay (IVCD) as assessed by intracardiac recording. Sensitivity and specificity of the electrocardiography (ECG) criteria assessed in patients with LBBB or IVCD. A total of 75 patients (median [IQR] age, 63 [53-70.5] years; 21 [28.0%] female) with baseline LBBB on 12-lead ECG underwent intracardiac recording of the left ventricular septum: 48 demonstrated complete conduction block (CCB) and 27 demonstrated intact Purkinje activation (IPA). Analysis of surface ECGs revealed that late notches in the QRS complexes of lateral leads were associated with CCB (40 of 48 patients [83.3%] with CCB vs 13 of 27 patients [48.1%] with IPA had a notch or slur in lead I; P = .003). Receiver operating characteristic curves for all septal and lateral leads were constructed, and lead I displayed the best performance with a time to notch longer than 75 milliseconds. Used in conjunction with the criteria for LBBB from the American College of Cardiology/American Heart Association/Heart Rhythm Society, this criterion had a sensitivity of 71% (95% CI, 56%-83%) and specificity of 74% (95% CI, 54%-89%) in the derivation population, contrasting with a sensitivity of 96% (95% CI, 86%-99%) and specificity of 33% (95% CI, 17%-54%) for the Strauss criteria. In an independent validation cohort of 46 patients (median [IQR] age, 78.5 [70-84] years; 21 [45.7%] female) undergoing TAVR with interval development of new LBBB, the time-to-notch criterion demonstrated a sensitivity of 87% (95% CI, 74%-95%). In the subset of 10 patients with preprocedural IVCD, the criterion correctly distinguished IVCD from LBBB in all cases. Application of the Strauss criteria performed similarly in the validation cohort. The findings suggest that time to notch longer than 75 milliseconds in lead I is a simple ECG criterion that, when used in conjunction with standard LBBB criteria, may improve specificity for identifying patients with LBBB from conduction block. This may help inform patient selection for cardiac resynchronization or conduction system pacing.

Prevalence and Clinical Significance of Electrocardiographic Complete Right Bundle Branch Block in Young Individuals.

There is limited information on the clinical significance of complete right bundle branch block (CRBBB) in young individuals. The aim of this study was to determine the prevalence and significance of CRBBB in a large cohort of young individuals aged 14-35 years old. From 2008 to 2018, 104,369 consecutive individuals underwent a cardiovascular assessment with a health questionnaire, electrocardiogram, clinical consultation, and selective echocardiography. Follow-up was obtained via direct telephone consultations. Mean follow-up was 7.3 ± 2.7 years. CRBBB was identified in 154 (0.1%) individuals and was more prevalent in males compared with females (0.20% vs. 0.06%; p<0.05) and in athletes compared with non-athletes (0.25% vs. 0.14%; p<0.05). CRBBB-related cardiac conditions were identified in 7 (5%) individuals (4 with atrial septal defect, 1 with Brugada syndrome, 1 with progressive cardiac conduction disease and 1 with atrial fibrillation). Pathology was more frequently identified in individuals with non-isolated CRBBB compared with individuals with isolated CRBBB (14% vs 1%; p < 0.05) and in individuals with a QRS duration of ≥130 milliseconds (ms) compared with individuals with a QRS of <130ms (10% vs 1%; p<0.05). The prevalence of CRBBB in young individuals was 0.1% and was more prevalent in males and athletes. CRBBB-related conditions were identified in 5% of individuals and were more common in individuals with non-isolated CRBBB and more pronounced intraventricular conduction delay (QRS duration of ≥130ms). Secondary evaluation should be considered for young individuals with CRBBB with symptoms, concerning family history, additional electrocardiographic anomalies or significant QRS prolongation (≥130ms).

Ultra-High-Frequency ECG in Cardiac Pacing and Cardiac Resynchronization Therapy: From Technical Concept to Clinical Application.

Identifying electrical dyssynchrony is crucial for cardiac pacing and cardiac resynchronization therapy (CRT). The ultra-high-frequency electrocardiography (UHF-ECG) technique allows instantaneous dyssynchrony analyses with real-time visualization. This review explores the physiological background of higher frequencies in ventricular conduction and the translational evolution of UHF-ECG in cardiac pacing and CRT. Although high-frequency components were studied half a century ago, their exploration in the dyssynchrony context is rare. UHF-ECG records ECG signals from eight precordial leads over multiple beats in time. After initial conceptual studies, the implementation of an instant visualization of ventricular activation led to clinical implementation with minimal patient burden. UHF-ECG aids patient selection in biventricular CRT and evaluates ventricular activation during various forms of conduction system pacing (CSP). UHF-ECG ventricular electrical dyssynchrony has been associated with clinical outcomes in a large retrospective CRT cohort and has been used to study the electrophysiological differences between CSP methods, including His bundle pacing, left bundle branch (area) pacing, left ventricular septal pacing and conventional biventricular pacing. UHF-ECG can potentially be used to determine a tailored resynchronization approach (CRT through biventricular pacing or CSP) based on the electrical substrate (true LBBB vs. non-specified intraventricular conduction delay with more distal left ventricular conduction disease), for the optimization of CRT and holds promise beyond CRT for the risk stratification of ventricular arrhythmias.

Reverse Septal Movement: A Step Forward in the Comprehension of the Underlying Causes.

(1) Background: Reverse septal movement (RSM) often occurs after cardiac surgery, consisting of a paradoxical systolic movement of the interventricular septum. In this retrospective study, we aimed to investigate possible determinants of RSM after coronary artery bypass surgery (CABG). (2) Methods: Patients who underwent CABG with on- or off-pump techniques at our center from March 2019 to October 2021 were retrospectively included. Exclusion criteria were: exposure to combined procedures (e.g., valve implantation), prior cardiac surgery, intraventricular conduction delays, and previous pacemaker implantation. Laboratory tests and echocardiographic and cardiopulmonary bypass (CPB) duration data were collected. (3) Results: We enrolled 138 patients, of whom 32 (23.2%) underwent off-pump CABG. Approximately 89.1% of the population was male; the mean age was 70 ± 11 years. There was no difference in RSM incidence in patients undergoing the off-pump and on-pump techniques (71.9% vs. 62.3%; p = 0.319). In patients undergoing on-pump surgery, the incidence of RSM was slightly higher in longer CPB procedures (OR 1.02 (1.00-1.03) p = 0.012), and clamping aortic time was also greater (OR 1.02 (1.00-1.03) p = 0.042). (4) Conclusions: CPB length seems to be correlated with a higher RSM appearance. This better knowledge of RSM reinforces the safety of CABG and its neutral effect on global biventricular function.

Personalized cardiac resynchronization therapy guided by real-time electrocardiographic imaging for patients with non–left bundle branch block

BackgroundPatients with heart failure and a non–left bundle branch block (non-LBBB) QRS pattern have a limited response to biventricular pacing (BVP). ObjectiveA personalized cardiac resynchronization therapy (CRT) implantation approach guided by real-time electrocardiographic imaging (ECGi) was studied. MethodsTwenty patients with left ventricular ejection fraction (LVEF) ≤ 35%, QRS duration ≥ 120 ms, and non-LBBB [13 (65%) with right bundle branch block and 7 (35%) with intraventricular conduction delay] were recruited. During CRT implantation, right atrial, right ventricular, coronary sinus, His-bundle, and/or left bundle leads were inserted. The total activation time (TAT) with different pacing combinations were measured in real time during implantation by ECGi. The configuration producing the shortest TAT was chosen. Clinical response was defined as ≥1 New York Heart Association class improvement. Echocardiographic response was defined as left ventricular end-systolic volume reduction ≥ 15% and/or LVEF improvement ≥ 10% at 6 months. ResultsAfter ECGi-guided CRT implantation, LVEF improved from 26% ± 6% to 34% ± 11% (P < .01) and New York Heart Association class improved from 3.0 ± 0.5 to 2.0 ± 0.6 (P < .01). Both clinical and echocardiographic response rates were 70%. The ECGi approach resulted in better acute electrical resynchronization over BVP as measured by TAT reduction (40% vs 14%; P < .01). The percentage of TAT reduction was found to be a strong predictor for echocardiographic response (area under the curve for the receiver operating characteristic curve 0.91; 95% confidence interval 0.78–1.00). A strong positive correlation between percentage TAT reduction and percentage LVEF improvement (Pearson R = 0.70; P = .001) was found. ConclusionECGi-guided CRT implantation in patients with non-LBBB generates superior acute electrical resynchronization compared with BVP and is associated with favorable clinical and echocardiographic outcomes.

Local VA index for the differential diagnosis of supraventricular tachycardia

BackgroundDifferentiating between atypical atrioventricular nodal reentrant tachycardia (AVNRT) and orthodromic reciprocating tachycardia utilizing a septal accessory pathway is a complex challenge. ObjectiveThe purpose of this study was to describe the "local VA index," a straightforward method based on signals from the coronary sinus catheter, to distinguish between these arrhythmias during tachycardia and entrainment. The ventriculoatrial (VA) interval on the coronary sinus catheter is measured during tachycardia and entrainment, at the site of earliest atrial activity. The difference between these 2 situations defines the “local VA index.” We also propose a mechanism to clarify the limitations of historical pacing maneuvers, such as postpacing interval minus tachycardia cycle length (PPI-TCL) and stimulus–atrial interval minus ventriculoatrial interval (SA-VA), by examining nodal decrement and intraventricular conduction delay. MethodsIn a retrospective study of 75 patients referred for supraventricular tachycardia evaluation, 37 were diagnosed with atrioventricular reentrant tachycardia (AVRT) with orthodromic reciprocating tachycardia, and 38 with AVNRT (27 typical, 11 atypical). ResultsIn comparison to AVRT patients, AVNRT patients exhibited longer PPI-TCL (176 ± 47 ms vs 113 ± 42 ms; P <.01) and SA-VA (138 ± 47 ms vs 64 ± 28 ms; P <.01). The AVRT group had mean local VA index of –1 ± 13 ms, whereas the AVNRT group had a significantly longer index of 91 ± 46 ms (P <.01). An optimal threshold for differentiation was a local VA index of 40 ms. Importantly, there was no significant correlation between pacing cycle length and nodal decrement as well as intraventricular delay related to pathway location. This interindividual variability might explain misleading interpretations of PPI-TCL and SA-VA. ConclusionThis novel approach is advantageous because of its simplicity and effectiveness, requiring only 2 diagnostic catheters. A local VA interval difference <40 ms provides a clear distinction for AVRT.

Clinical characteristics, diagnosis and management of nivolumab-induced myocarditis.

Nivolumab can cause fatal myocarditis. We aimed to analyze the clinical characteristics of nivolumab-induced myocarditis and provide evidence for clinical diagnosis, treatment, and prevention. Studies involving nivolumab-induced myocarditis were identified in electronic databases from 2000 to 2023 for retrospective analysis. A total of 66 patients were included, with a median age of 68 years. The median onset time of myocarditis is 11.5 days. The main organs affected in persons presented with myocarditis are heart (100.0%) and skeletal muscle (22.7%). The main clinical manifestations are dyspnea (49.2%), fatigue (47.6%), and myalgias (25.4%). The levels of troponin, troponin T, troponin I, creatine kinase, creatine kinase myocardial band, creatine phosphokinase, C-reactive protein, brain natriuretic peptide, and N-terminal brain natriuretic peptide precursor were significantly increased. Histopathology often shows lymphocyte infiltration, myocardial necrosis, and fibrosis. Myocardial immunological parameters usually present positive. Cardiac imaging often suggests complete heart block, intraventricular conduction delay, arrhythmia, myocardial infarction, edema, left ventricular ejection fractions reduction, ventricular dysfunction, and other symptoms of myocarditis. Forty-two (63.6%) patients achieved remission within a median time of 8 days after discontinuation of nivolumab and treatment with systemic corticosteroids, immunoglobulins, plasmapheresis, and immunosuppressant. Thirty-five patients eventually died attributed to myocarditis (68.6%), cancer (20.0%), respiratory failure (5.7%), and other reasons (5.7%). Nivolumab-induced myocarditis should be comprehensively diagnosed based on clinical symptoms, histopathological manifestations, immunological parameters, and cardiac function imaging examinations. Nivolumab should be discontinued immediately, plasmapheresis and systemic corticosteroids combined with immunoglobulins or immunosuppressants may be an effective treatment.

The number of screwing attempt and predictors for the success of left bundle branch area pacing : A multicenter experience with standard stylet-driven pacing leads

Abstract Objectives Although Left Bundle Branch Area Pacing (LBBAP) is emerging conduction system pacing modality, it is unclear which parameters are predictive of procedural success and how many screwing attempts are acceptable. This retrospective observational study sought to assess predictors of successful LBBAP, left bundle branch (LBB) capture, and factors associated with the number of screwing attempts. Methods We performed a multicenter retrospective analysis of 120 patients who underwent LBBAP with stylet driven lead. We analyzed factors affecting the number of screwing attempts and procedural success. Procedural, 12-lead ECG, echocardiographic parameters and clinical variables were used in multivariate analyses. Results LBBAP success rate was 95.8% (115/120), and LBB capture success rate was 86.1% (99/115). Few screwing attempts was associated with procedural success (2.1 ± 1.2, 2.7 ± 1.2, and 3.5 ± 1.3 in LBBAP with LBB capture, LBBAP without LBB capture and failed LBBAP group, respectively) (p for trends=0.03). 4 or more screwing attempt was independently associated with higher complication rate compared to fewer screwing attempt (n≤3) (p&amp;lt;0.05). The larger RA size (B = 1.901, 95% confidence interval [CI] 1.07 - 2.73, p &amp;lt;0.001), smaller RV size (B = -0.995, 95% CI -1.88 - -0.31, p = 0.007), and intraventricular conduction delay (IVCD) at pre-implant ECG were independently associated with more screwing attempts. Larger RA size (4th quartile) was associated with larger final sheath size and frequent sheath size change to larger sheath when compared to others. Conclusions More screwing attempts was associated with failed LBBAP procedure and failed LBB capture, and 4 or more screw attempts was associated with higher complication rate. Larger the RA size, smaller the RV size, and IVCD in pre-implant ECG are predictive of more screwing attempt.

Personalized cardiac resynchronization therapy guided by real-time electrocardiographic imaging for non-left bundle branch block patients

Abstract Background Heart failure patients with non-left bundle branch block (non-LBBB) QRS pattern have limited response rate to biventricular pacing (BVP). Objective A personalized cardiac resynchronization therapy (CRT) implantation approach guided by real-time electrocardiographic imaging (ECGi) was studied. Methods Twenty patients with left ventricular ejection fraction (LVEF) ≤35%, QRS duration ≥120ms and non-LBBB (13 right bundle branch block and 7 intraventricular conduction delay) were recruited. During CRT implantation, right atrial, right ventricular, coronary sinus, His-bundle and/or Left-bundle leads were inserted. The total activation time (TAT) with different pacing combinations were measured real-time during implantation by ECGi. The configuration producing shortest TAT would be chosen. Clinical response was defined as ≥1 New York Heart Association (NYHA) class improvement. Echocardiographic response was defined as LV end systolic volume reduction ≥15% and/or LVEF improvement ≥10% at 6-months. Results After ECGi guided CRT implantation, LVEF improved from 26±6% to 34±11% (both p&amp;lt;0.01) and NYHA class improved from 3.0±0.5 to 2.0±0.6 (p&amp;lt;0.01). Both clinical and echocardiographic response rates were 70%. ECGi approach resulted in better acute electrical resynchronization over BVP as measured by TAT reduction (40% vs 14%, p&amp;lt;0.01). Percentage of TAT reduction was found to be a strong predicator for echocardiographic response (AUC for ROC curve 0.91, 95% CI 0.78 – 1.00). A strong positive correlation between percentage TAT reduction and percentage LVEF improvement (Pearson R 0.70, p=0.001) was found. Conclusions ECGi guided CRT implantation in non-LBBB patients generates superior acute electrical resynchronization compared with BVP and is associated with favorable clinical and echocardiographic outcomes.

External validation of the new REACT-HF score for heart failure prediction in patients with atrial fibrillation

Abstract Background Heart failure (HF) represents the main cause of hospital admissions and deaths among atrial fibrillation (AF) patients, but precise risk prediction tools are lacking. Recently, the REACT-HF score has been developed to predict incident HF hospitalizations or cardiovascular (CV) death within 2-years based on 12 variables (sex, age, height, creatinine clearance, diabetes, vascular disease, valvular heart disease, heart rate and rhythm, left ventricular hypertrophy and intraventricular conduction delay). Purpose The aim of the present study was to externally validate the REACT-HF score within the Swiss-AF and BEAT-AF cohorts, and to investigate whether this score model can be improved by adding biomarkers (hs-CRP, NT-proBNP, hs-TNT). Methods We included 2’599 AF patients from the Swiss- and BEAT-AF cohorts without prior history of HF, with at least one follow-up and with all baseline variables needed for the REACT-HF score. To validate the score, we estimated a Cox model with the original score as the only predictor. We further explored whether the predictive performance of the REACT-HF score model could be improved by adding any combination of the above listed biomarkers. The primary outcome was incident HF hospitalization or CV death. Secondary outcomes included the individual components of the primary outcome and all-cause mortality. Results Mean age was 70.2 years, 29.1% were female and 54.8% had paroxysmal AF. The mean CHA2DS2-VASc score was 2.7 (+/- 1.6). The most frequent comorbidities were hypertension (65%), diabetes (12%), vascular disease (23%) and coronary artery disease (36%). Most patients (1’883) presented a very low REACT-HF score below 0.05 (72.4%), 530 patients between 0.05 and below 0.1 (20.4%) and 186 had a risk score of 0.1 and above (7.2%). In the validation set, 380 (14.6%), 471 (18.1%), 511 (19.7%) 561 (21.6%) and 676 (26.0%) patients were categorized in the lowest to the highest quintiles based on the original score`s quintiles. Figure 1 shows the Kaplan-Meier survival curves for the primary endpoint of first HF hospitalization or CV death by quintiles of the REACT-HF score, applied in our pooled cohort. And Figure 2 shows the Kaplan-Meier curves for the 1st HF hospitalization. The incidence rates at 2-year follow-up per 100 patient-years of the primary outcome (0.39, 0.59, 1.58, 3.97, 7.53), HF hospitalization (0.39, 0.49, 1.38, 2.75, 6.26), CV death (0.0, 0.10, 0.20, 1.29, 2.12), and all cause-death (0.10, 0.49, 0.78, 2.29, 4.24) all increased gradually among the quintiles of risk score. The estimated c-statistic for the composite primary outcome was 0.764 (approximate 95% CI, 0.723-0.806). The best biomarker enhanced-model within our cohort was the model including hs-CRP and NT-proBNP (c-statistic 0.810). Conclusions The REACT-HF score discriminates well for prediction of HF hospitalization and CV death in a contemporary AF population and can be improved by including NT-pro-BNP and hs-CRP.

Abstract 16791: Conduction System Response to Cardiac Resynchronization Therapy

Background: Cardiac resynchronization therapy (CRT) can be an effective treatment for cardiomyopathy patients with intraventricular conduction delay. However, significant controversy remains over the effect of QRS duration shortening on CRT outcomes. We hypothesize that reduction in QRS duration following CRT implantation is associated with echocardiographic outcomes. Methods: We included all adult patients with structural heart disease and CRT followed at UCLA. We reviewed all available electrocardiograms (ECG) and echocardiograms. We excluded patients with CRT for complete heart block, congenital heart disease, and those without intrinsic QRS ECGs prior to CRT. Patients were categorized as left bundle branch block (LBBB) if Strauss criteria were met prior to CRT implantation. Other patterns (including right bundle branch block with QRS duration ≥150ms) were classified as IVCD. We evaluated QRS duration before and immediately after CRT implantation. Changes in QRS duration post-CRT implant were calculated in percentage change. Echocardiograms were evaluated for changes in left ventricular end diastolic dimension (LVIDD) and ejection fraction (LVEF) following CRT implantation. Results: We included 108 patients (mean age of implant 66.1±12.8 years, 65% male, 63% nonischemic cardiomyopathy). Of these, 44 patients (41%) had LBBB. After CRT, patients with LBBB had significant decrease in QRS duration (-9.3±17.0% vs +16.9±30.9%, p &lt; 0.001), improvement in LVEF (12.1±10.5% vs 1.85±10.7%, p &lt; 0.001) and reduction in LVIDD (-0.6±0.7cm vs 0.1±0.7cm, p &lt; 0.001) compared to patients with IVCD. Decrease in QRS duration was significantly correlated with both improvement in LVEF (Pearson r = 0.21, p = 0.037) and reduction in LVIDD (Pearson r = 0.28, p = 0.006). Conclusion: CRT resulted in significantly larger decrease in QRS duration amongst patients with LBBB compared to IVCD. QRS duration reduction was, in turn, significantly correlated with improvements in LVIDD and LVEF. This likely reflects the proximal nature of true LBBB, and the ability of CRT to utilize the remaining distal Purkinje system for impulse propagation. Further research on the electrical and mechanical response to CRT can help guide optimization of target populations.

Abstract 15996: Pre-Operative Predictors of Permanent Pacemaker Implantation Post Aortic Valve Replacement: A Retrospective Cohort Evaluation

Introduction: Permanent pacemaker (PPM) implantation following Aortic Valve Replacement (AVR) is common. While AVR modality choice (i.e. surgical vs. transcatheter) affects PPM risk, identifying pre-operative factors associated with increased PPM risk can benefit enhanced risk assessment and care decisions. Methods: This study is a retrospective evaluation of pre-operative factors associated with PPM risk within 1-month post-AVR at a tertiary care centre (2014-2020). Pre-AVR conduction abnormalities were classified as left bundle (LBBB), right bundle branch blocks (RBBB), and other abnormalities (left anterior/posterior fascicular block, intraventricular conduction delay) in combination with RBBB, LBBB, or alone. Results: Of the 776 (mean age= 74, 66% male) patients, 89 (11.5%) subsequently received PPM. As per pre-AVR electrocardiogram, 76 (9.8) were not in sinus rhythm and 214 (27.6%) had conduction abnormalities, including: 81 (10.4%) LBBB and LBBB + other, 91 (11.7%) RBBB and RBBB + other, and 42 (5.4%) other abnormalities. Pre-AVR rhythm (18.4 vs. 10.7%, p=0.05) and conduction abnormalities (19.2 vs. 8.5%, p&lt;0.0001) were significantly associated with the need for post-AVR PPM. No statistically significant differences were observed in other demographic-clinical characteristics. Logistic regression, adjusted for age and sex, indicated significantly higher post-AVR PPM risk for patients with RBBB and RBBB + other (OR= 3.84, 95%CI: 2.21-6.66, p&lt;0.0001) and other miscellaneous (OR= 2.58, 95%CI: 1.13-5.93, p&lt;0.03) abnormalities, but not for LBBB and LBBB + other (OR= 1.14, 95%CI: 0.52-2.50, p&lt;0.75) compared to participants with no pre-AVR conduction abnormalities. Females experienced significantly lower need for PPM (OR= 0.60, 95%CI: 0.35-1.00, p= 0.05). Conclusions: Pre-AVR RBBB and other conduction abnormalities alone or together, but not LBBB are associated with significantly higher need for post-AVR PPM.

Electrocardiographic characteristics associated with late gadolinium enhancement and prognostic value in patients with dilated cardiomyopathy.

Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging has emerged as an important tool for assessment of patients with dilated cardiomyopathy (DCM). Electrocardiography (ECG) is an accessible, reproducible, low-cost diagnostic and prognostic tool. This study aimed to investigate the ECG characteristics associated with LGE, as well as to assess the prognostic significance of ECG in patients with DCM. Consecutive patients diagnosed with DCM by CMR [left ventricular ejection fraction (LVEF) < 50%] between 2011 and 2020 were included. Multivariable analysis was conducted to evaluate ECG predictors associated with LGE. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of ECG in combination of clinical data and LVEF for LGE. Two composite outcomes were also assessed among patients with and without ECG predictors: (1) sudden cardiac death (SCD), sustained ventricular arrhythmia, or appropriate implantable cardioverter-defibrillator (ICD) therapy, and (2) all-cause death or hospitalization for heart failure. A total of 422 patients, with a mean age of 59.5 ± 16.3 years (58.3% male), were included. LGE was present in 169 (40%) of the patients. Multivariable analysis identified lateral inverted T-waves, intraventricular conduction delay, low voltage, and fragmented QRS as independent predictors of LGE. ROC analysis showed a significant increase in the area under the curve (AUC) when ECG predictors of the four aforementioned characteristics were added to the clinical-LVEF model (AUC 0.66, 95% CI 0.59-0.71 vs. 0.72, 95% CI 0.67-0.78, p = 0.003). During a median follow-up of 2.7 years (IQR 0.8, 5.2), 16 events of SCD, sustained ventricular arrhythmia, or appropriate ICD therapy, and 70 events of all-cause death or hospitalization for heart failure occurred. ECG predictors were independently associated with SCD, sustained ventricular arrhythmia, or appropriate ICD therapy (HR 4.84, 95% CI 1.34-17.40, p = 0.01). However, ECG predictors were not associated with all-cause death or hospitalization for heart failure (HR 1.22, 95% CI 0.76-1.96, p = 0.39). In patients with DCM, lateral inverted T-waves, intraventricular conduction delay, low voltage, and fragmented QRS were independently associated with LGE. Additionally, these ECG predictors had prognostic value for predicting SCD, sustained ventricular arrhythmia, or appropriate ICD therapy, assisting clinicians in stratifying SCD risk and identifying primary prevention ICD implantation candidates.