Fascicular Block Research Articles

Abstract 4136989: Association of alternating PR intervals with paroxysmal atrioventricular block in patients with right bundle branch block following cardiac surgery

Background: We previously observed a positive correlation between QRS duration and the preceding RP interval in sinus rhythm in certain patients experiencing new onset left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR). This unique phenomenon, termed inverse decremental conduction ( IDC ) or Yan conduction, prompted us to investigate whether IDC in the left bundle could manifest as AV conduction in an IDC pattern in patients with preexisting right bundle branch block (RBBB) and its association with atrioventricular block (AVB). Methods: 12 lead ECGs, available in-patient telemetry and mobile cardiac outpatient telemetry were reviewed in patients with sinus rhythm and preexisting RBBB who developed paroxysmal AVB requiring temporary or permanent pacemaker within 7 days following any types of cardiac surgery from 2014 to 2023 in Lankenau Medical Center. Results: A total of 9 patients (5 males) with a mean age of 71±15 years were identified to exhibit PR interval changes consistent with IDC prior to paroxysmal AVB. Among these patients, 6 had undergone TAVR, while the remaining 3 had undergone surgical aortic valve replacement, mitral valve repair, and ventricular septal defect repair, respectively. Specifically, PR interval alternation in the setting of RBBB occurred during sinus rhythm in a pattern that the longer RP interval is followed by a longer PR interval (Figure 1). This pattern exhibits the following features: 1) 8 of 9 patients had RBBB plus left anterior fascicular block (LAFB); 2) PR alternation occurred at sinus rates from 68 to 91 bpm within 5 days following surgical procedures; 3) proximal AVB occurred within 1 to 12 hours after PR interval alternation began. A positive correlation was established between PR and preceding RP interval in 2 of 9 patients whose telemetry data were available for analysis ( Figure 2A ). In a patient with RBBB who developed paroxysmal AVB without IDC changes in the PR interval post TAVR, intracardiac recording showed a decrease in AH interval but an increase in HV interval with slowing heart rates ( Figure 2B ), indicating that decremental conduction in AV node can mask IDC in Purkinje system. Conclusion: 1) PR alternation with longer PR following longer preceding RP interval in presence of RBBB, likely due to IDC in left bundle, heralds paroxysmal AVB; 2) PR interval changes resulting from IDC in left bundle in the setting of RBBB may be masked by decremental conduction in AV node.

Abstract 4137975: 9-Year Longitudinal Assessment of the 12-lead Electrocardiogram of Volunteer Firefighters

Introduction: In the US, the most common cause of death among active-duty firefighters is sudden cardiac death (SCD). Underlying heart diseases are important propagator of ventricular tachyarrhythmias that cause SCD. The objective of this abstract is to assess the incidence of underlying heart disease, identified on 12-lead electrocardiograph (ECG), that may place firefighters at greater risk of SCD. Methods: We digitalized 12-lead ECGs recorded among firefighters who visited a firefighter health screening program at least 4 times from 2011-2019. We extracted the interval measurements (Heart Rate, T-axis, QRS-axis, QRS duration, QTc duration) and interpretation statements from each of the 12-lead ECGs and grouped potential propagators of ventricular tachyarrhythmias including left ventricular hypertrophy (LVH), coronary artery disease (CAD), and cardiac conduction disease. We used simple mean imputation to handle missing data. Descriptive statistics including means and frequencies were used to analyze the sample. Results: Among 465 firefighters (90.1% male) with a mean age of 47.1 (±13.6) whom 1,296 12-lead ECGs were analyzed, 21.5% (n=278) of Heart Rate, 0.39% (n=5) T-axis, 26.4% (n=342) QRS-axis, 40.0% (n=518) QRS duration, 5.40% (n=70) QTc duration were abnormal. In addition to intervals, the 12-lead ECGs generated 1,970 interpretation statements of which 28.2% (n=555) were deemed possible pathoanatomical substrates including 3.1% (n=34) LVH, 24.7% (n=137) CAD, and 69.2% (n=384) cardiac conduction diseases. Among cardiac conduction diseases, intraventricular conduction disease was the most prevalent (n=204, 36.8%), followed by vertical axis (n=70, 12.6%), right bundle branch block (n=59, 10.6%), left anterior fascicular block (n=34, 6.1%), and left bundle branch block (n=17, 3.1%). Interestingly, we did not observe a temporal relationship regarding the number of pathoanatomical substrates over the screening period. Conclusions: Nearly 30% of the interpretation statements generated from 12-lead ECGs were indicative of possible pathoanatomical substrates that cause SCD, which reflects the apparently negative effect of fire suppression activity on one’s cardiopulmonary health. Our result justifies the imperative need of effective prevention method for cardiac conduction diseases among firefighters. Further research is needed to collect 12-lead ECG systematically amongst other measures such as diet and BMI which reflect work culture and lifestyle of firefighters.

Evolution over time of cardiac biomarkers, electrocardiographic and echocardiographic features in a large cohort of patients with wild-type transthyretin cardiac amyloidosis treated with tafamidis

Abstract Introduction Data on evolution of transthyretin wild-type cardiac amyloidosis (ATTRwt) during treatment with tafamidis is scarce. This hinders the quest for parameters of response and a priori treatment eligibility. Purpose To study the evolution of biomarkers, ECG, and echocardiographic features during early tafamidis treatment. Methods We prospectively collected data after 12-18 months of treatment in a single-centre database. Changes of NT-proBNP and high-sensitivity Troponin I (hs-cTnI) between baseline and follow-up evaluations (at 12 and 18 months) were tested for significance. For ECG and echocardiographic features, we considered baseline and the last available follow-up (median interval 11.1 months). Results We included 253 patients (median age 77[71-82]years; 90% males). Median (IQR) baseline NT-proBNP was 2472(1355-4749)ng/L, hs-cTnI 47(30-82)ng/L. Furosemide was administered in 58% of cases (median dose 25[25-50]mg/day). Compared to baseline, NT-proBNP was 2342(1316-4148)ng/L at 12 (p=0.886), and 2633(1393-6063)ng/L at 18 months (p=0.285), with 4% and 30% of patients showing ≥30% and ≥300ng/L increase at 12 and 18 months, respectively; hs-cTnI was 46(29-70)ng/L at 12 (p=0.947), and 44(25-68)ng/L at 18 months (p=0.866), with 35% and 7% showing a ≥20% increase at 12 and 18 months, respectively, and 21 (11.5% over 183 analyzable) with increase at 12 and reduction at 18 months. Patients on furosemide were 69% and 70% at 12 and 18 months, respectively; the dose increased to 37.5(25-75)mg/day at 18 months (p=0.009). At baseline, 117(47%) patients had history/permanent atrial fibrillation (AF). Forty-one(16%) had an implantable electronic device, 16(6%) underwent subsequent implantation. Median PR interval was 210(185-240)msec, trending toward prolongation (p=0.054). QRS duration increased (100[86-130]vs120[90-140]msec, p=0.004), together with conduction disturbances (left anterior fascicular block 30[21%]vs43[29%], p=0.036; right bundle branch block 14[10%]vs27[18%], p=0.002). AF prevalence raised from 19% to 25%. There were no significant changes in left ventricular (LV) geometry (septum thickness 18[16-20]vs18[16-20]mm, p=0.666; end-diastolic diameter 45±7vs45±8mm, p=0.434), systolic function (ejection fraction 51±10%vs49±11%, p=0.070), filling pressures (E/e’ 17[11-20]vs14.9[13-19], p=0.086) and left atrial size (mean volume 46±15vs48±13ml/m2, p=0.649). Tricuspid annular plane systolic excursion (18±4vs17±4mm) and pulmonary artery systolic pressure (40[33-45]vs36[30-45]mmHg) remained stable. Conclusions We did not observe neither improvement nor worsening of laboratory/instrumental variables within the first 12-18 months of tafamidis. There was a progression of electrical disorders. After initial progression hs-cTnI tended to improve. Extended follow-up and a matched case-control series will help identify possible later changes useful to monitor treatment response and effects of supporting heart failure treatments.

Detecting elevated left ventricular end diastolic pressure from simultaneously measured femoral pressure waveform and electrocardiogram

Objective. Instantaneous, non-invasive evaluation of left ventricular end-diastolic pressure (LVEDP) would have significant value in the diagnosis and treatment of heart failure. A new approach called cardiac triangle mapping (CTM) has been recently proposed, which can provide a non-invasive estimate of LVEDP. We hypothesized that a hybrid machine-learning (ML) method based on CTM can instantaneously identify an elevated LVEDP using simultaneously measured femoral pressure waveform and electrocardiogram (ECG). Approach. We studied 46 patients (Age: 39–90 (66.4 ± 9.9), BMI: 20.2–36.8 (27.6 ± 4.1), 12 females) scheduled for clinical left heart catheterizations or coronary angiograms at University of Southern California Keck Medical Center. Exclusion criteria included severe mitral/aortic valve disease; severe carotid stenosis; aortic abnormalities; ventricular paced rhythm; left bundle branch and anterior fascicular blocks; interventricular conduction delay; and atrial fibrillation. Invasive LVEDP and pressure waveforms at the iliac bifurcation were measured using transducer-tipped Millar catheters with simultaneous ECG. LVEDP range was 9.3–40.5 mmHg. LVEDP = 18 mmHg was used as cutoff. Random forest (RF) classifiers were trained using data from 36 patients and blindly tested on 10 patients. Main results. Our proposed ML classifier models accurately predict true LVEDP classes using appropriate physics-based features, where the most accurate demonstrates 100.0% (elevated) and 80.0% (normal) success in predicting true LVEDP classes on blind data. Significance. We demonstrated that physics-based ML models can instantaneously classify LVEDP using information from femoral waveforms and ECGs. Although an invasive validation, the required ML inputs can be potentially obtained non-invasively.

Long-term outcome after catheter ablation for fascicular ventricular tachycardia in a single high-volume center in Germany

Abstract Background Idiopathic Fascicular Ventricular Tachycardia (IFVT) accounts for less than 10% of all VTs and represents the most common idiopathic ventricular tachycardia of the left ventricle. This study reports on clinical and procedural characteristics and the long-term outcome of patients undergoing catheter ablation of premature ventricular complexes (PVC) and ventricular tachycardias (VTs) arising in proximity of the left ventricular conduction system. Methods and results This study includes 27 patients (17 male, 45 ± 17 years; 10 females, 50 ± 11 years) who underwent electrophysiological examinations at a tertiary ablation center over a period of 14 years (2009 to 2022). Follow-up was performed via regular Holter-ECGs and clinical evaluations, or via structured follow-up within the prospective TRUST registry. In 21/27 patients (77.8%), the left posterior fascicle (LPF) was involved in the IFVT. In 4 (14.8%) the left anterior fascicle (LAF) was involved and in 2 (7.4%) patients an origin in the upper septal (US) area was demonstrated. 22/27 (81.5%) patients had a preserved left ventricular ejection fraction (LVEF) and only 5 (18.5%) patients had a LVEF less than 50% at the time of presentation. 14/27 (51.9%) patients presented with PVC or non-sustained VTs with the following distribution: 10 (71.4%) originating from the LPF, 3 (21.4%) from the LAF and 1 (7.1%) from the US. 21/27 (77.8%) patients presented with sustained VTs: 16 (76.2%) arising from the LPF, 4 (19%) from the LAF and 1 (4.8%) from the US. However, only 2 (7.4%) patients presented in sustained VT at the beginning of the EP procedure. In 16 (59.3%) patients a sustained VT was induced during the EP study via isoprenaline and/or programmed ventricular stimulation. Mean QRS duration of the VT was 124.5 ± 14.6 msec. In 21 (77.7%) patients only a retrograde approach was used, in 3 (11.1%) patients a retrograde and an additional transeptal approach and in only 3 (11.1%) patients solely a transeptal approach. Mean number of radiofrequency applications was 11.8 ± 12.6 (30 to 40 Watts, 27545.6 ± 30524.4 Joules). FVT ablation was acutely successful in 24 patients (88.9%). In 2 patients (7.4%) no ablation was performed due to inability to induce VT under sedation. 3/27 patients (11.1%) underwent re-ablation due to FVT recurrence after previous ablation procedures. Moreover, 3 (11.1%) additional patients underwent repeated VT ablations during follow-up, but the arrhythmia originated from a different LV area. No procedure-related complication occurred. In 4 patients (14.8%) left fascicular posterior block was caused by ablation and in 3 (11.1%) patients a complete left bundle block. Mean procedure time was 130 ± 48.9 minutes. Conclusion Ablation of FVT in a tertiary ablation center is associated with a high single procedural success rate of 88.9% during long-term follow-up, with a mild risk of fascicular injury. 11.1% of patients underwent re-ablation due to FVT recurrence.

Prevalence and Clinical Significance of Intraventricular Conduction Disturbances in Hospitalized Children.

Introduction: Data on the prevalence and clinical significance of interventricular conduction disturbances (IVCDs) in children are scarce. While incomplete right bundle branch blocks (IRBBBs) seem to be the most frequent and benign findings, complete bundle blocks and fascicular blocks are often seen in children with congenital/acquired cardiac conditions. This study aims to delineate the prevalence and the diagnostic accuracy of IVCD in children admitted to a paediatric cardiology unit. Methods: Children admitted to the paediatric cardiology unit between January 2010 and December 2020 who had an ECG were included in the study. IVCDs were diagnosed according to standard criteria adjusted for age. Results: Three thousand nine hundred and ninety-three patients were enrolled. The median age was 3.1 years (IQR: 0.0-9.2 years), and 52.7% were males. IVCDs were present in 22.5% of the population: 17.4% of the population presented with IRBBBs, 4.8% with a complete right bundle branch block (CRBBB), 0.1% with a complete left bundle branch block (CLBBB), 0.2% with a left anterior fascicular block (LAFB) and 0.2% with a combination of CRBBB and LAFB. Also, 26% of children with congenital heart disease had an IVCD, and 18% of children with an IVCD had previous cardiac surgery. The overall sensitivity of IVCD in detecting a cardiac abnormality was 22.2%, with a specificity of 75.5%, a PPV of 83.1% and an NPV of 15.1%, but the values were higher for CLBBB and LAFB. Conclusions: IVCDs were present in one-fifth of children admitted to the cardiology unit. IRBBB was the most frequent disturbance, while CRBBB, CLBBB and fascicular blocks were much rarer, though they had a higher predictive value for cardiac abnormalities.

Different degrees of anterior displacement of QRS complex

Electrocardiogram of a patient affected by hypertrophic cardiomyopathy showed normal PR and QRS intervals and signs of left ventricular hypertrophy. In leads I,V5 and V6 the initial q waves were absent. A subsequent electrocardiogram revealed the appearance of prominent anterior QRS forces expressed by a change from rS to R pattern in leads V2 and V3 with a tall R wave in V2. PR and QRS intervals and QRS axis remained substantially unchanged. Other electrocardiograms showed day-to-day variations of the anterior displacement of QRS complex. The different degrees of anterior displacement appear to be an expression of an underlying left septal fascicular block, but a diagnosis cannot be made with certainty.

Predictors of pacemaker requirement in patients receiving implantable loop recorders for unexplained syncope: A systematic review and meta-analysis

BackgroundImplantable loop recorders (ILRs) are increasingly used to evaluate patients with unexplained syncope. Identification of all predictors of bradycardic syncope and consequent permanent pacemaker (PPM) insertion is of substantial clinical interest as patients in the highest risk category may benefit from upfront pacemaker insertion. ObjectiveWe performed a systematic review and meta-analysis to identify risk predictors for PPM insertion in ILR recipients with unexplained syncope. MethodsAn electronic database search (MEDLINE, Embase, Scopus, Cochrane) was performed in June 2023. Studies evaluating ILR recipients with unexplained syncope and recording risk factors for eventual PPM insertion were included. A random effects model was used to calculate the pooled odds ratio (OR) for clinical and electrocardiographic characteristics with respect to future PPM requirement. ResultsEight studies evaluating 1007 ILR recipients were included; 268 patients (26.6%) underwent PPM insertion during study follow-up. PPM recipients were older (mean age, 70.2 ± 15.4 years vs 61.6 ± 19.7 years; P < .001). PR prolongation on baseline electrocardiography was a significant predictor of PPM requirement (pooled OR, 2.91; 95% confidence interval, 1.63–5.20). The presence of distal conduction system disease, encompassing any bundle branch or fascicular block, yielded a pooled OR of 2.88 for PPM insertion (95% confidence interval, 1.53–5.41). Injurious syncope and lack of syncopal prodrome were not significant predictors of PPM insertion. Sinus node dysfunction accounted for 62% of PPM insertions, whereas atrioventricular block accounted for 26%. ConclusionApproximately one-quarter of ILR recipients for unexplained syncope require eventual PPM insertion. Advancing age, PR prolongation, and distal conduction disease are the strongest predictors for PPM requirement.

Chagas cardiomyopathy in Boston, Massachusetts: Identifying disease and improving management after community and hospital-based screening.

Limited data exist regarding cardiac manifestations of Chagas disease in migrants living in non-endemic regions. A retrospective cohort analysis of 109 patients with Chagas disease seen at Boston Medical Center (BMC) between January 2016 and January 2023 was performed. Patients were identified by screening and testing migrants from endemic regions at a community health center and BMC. Demographic, laboratory, and cardiac evaluation data were collected. Mean age of the 109 patients was 43 years (range 19-76); 61% were female. 79% (86/109) were diagnosed with Chagas disease via screening and 21% (23/109) were tested given symptoms or electrocardiogram abnormalities. Common symptoms included palpitations (25%, 27/109) and chest pain (17%, 18/109); 52% (57/109) were asymptomatic. Right bundle branch block (19%, 19/102), T-wave changes (18%, 18/102), and left anterior fascicular block (11%, 11/102) were the most common electrocardiogram abnormalities; 51% (52/102) had normal electrocardiograms. Cardiomyopathy stage was ascertained in 94 of 109 patients: 51% (48/94) were indeterminate stage A and 49% (46/94) had cardiac structural disease (stages B1-D). Clinical findings that required clinical intervention or change in management were found in 23% (25/109), and included cardiomyopathy, apical hypokinesis/aneurysm, stroke, atrial or ventricular arrhythmias, and apical thrombus. These data show high rates of cardiac complications in a cohort of migrants living with Chagas disease in a non-endemic setting. We demonstrate that Chagas disease diagnosis prompts cardiac evaluation which often identifies actionable cardiac disease and provides opportunities for prevention and treatment.

Long-Term Atrioventricular Block Following Valve Surgery: Electrocardiographic and Surgical Predictors.

Bradyarrhythmia requiring pacemaker implantation among patients undergoing valve surgery may occur even after several years, with unclear predictors. Our aim was to investigate the incidence of pacemaker implantation at different follow-up times and identify associated predictors. We conducted a retrospective study evaluating 1046 consecutive patients who underwent valve surgery at the Cardiac Surgery Division of Bologna University Hospital from 2005 to 2010. During 10 ± 4 years of follow-up, 11.4% of these patients required pacemaker implantation. Interventions on both atrioventricular valves independently predicted long-term pacemaker implantation (SHR 2.1, 95% CI 1.2-3.8, p = 0.014). Preoperative atrioventricular conduction disease strongly predicted long-term atrioventricular block, with right bundle branch block as the major predictor (SHR 7.0, 95% CI 3.9-12.4, p < 0.001), followed by left bundle branch block (SHR 4.9, 95% CI 2.4-10.1, p < 0.001), and left anterior fascicular block (SHR 3.9, 95% CI 1.8-8.3, p < 0.001). Patients undergoing valvular surgery have a continuing risk of atrioventricular block late after surgery until the 12-month follow-up, which was clearly superior to the rate of atrioventricular block observed at long-term. Pre-operative atrioventricular conduction disease and combined surgery on both atrioventricular valves are strong predictors of atrioventricular block requiring pacemaker implantation.

Electrocardiographic predictors of left ventricular scar in athletes with right bundle branch block premature ventricular beats.

Right bundle branch block (RBBB) morphology non-sustained ventricular arrhythmias (VAs) have been associated with the presence of non-ischaemic left ventricular scar (NLVS) in athletes. The aim of this cross-sectional study was to identify clinical and electrocardiogram (ECG) predictors of the presence of NLVS in athletes with RBBB VAs. Sixty-four athletes [median age 39 (24-53) years, 79% males] with non-sustained RBBB VAs underwent cardiac magnetic resonance (CMR) with late gadolinium enhancement in order to exclude the presence of a concealed structural heart disease. Thirty-six athletes (56%) showed NLVS at CMR and were assigned to the NLVS positive group, whereas 28 athletes (44%) to the NLVS negative group. Family history of cardiomyopathy and seven different ECG variables were statistically more prevalent in the NLVS positive group. At univariate analysis, seven ECG variables (low QRS voltages in limb leads, negative T waves in inferior leads, negative T waves in limb leads I-aVL, negative T waves in precordial leads V4-V6, presence of left posterior fascicular block, presence of pathologic Q waves, and poor R-wave progression in right precordial leads) proved to be statistically associated with the finding of NLVS; these were grouped together in a score. A score ≥2 was proved to be the optimal cut-off point, identifying NLVS athletes in 92% of cases and showing the best accuracy (86% sensitivity and 100% specificity, respectively). However, a cut-off ≥1 correctly identified all patients with NLVS (absence of false negatives). In athletes with RBBB morphology non-sustained VAs, specific ECG abnormalities at 12-lead ECG can help in detecting subjects with NLVS at CMR.

Amyloid Burden Correlates with Electrocardiographic Findings in Patients with Cardiac Amyloidosis-Insights from Histology and Cardiac Magnetic Resonance Imaging.

Cardiac amyloidosis (CA) is associated with several distinct electrocardiographic (ECG) changes. However, the impact of amyloid depositions on ECG parameters is not well investigated. We therefore aimed to assess the correlation of amyloid burden with ECG and test the prognostic power of ECG findings on outcomes in patients with CA. Consecutive CA patients underwent ECG assessment and cardiac magnetic resonance imaging (CMR), including the quantification of extracellular volume (ECV) with T1 mapping. Moreover, seven patients underwent additional amyloid quantification using immunohistochemistry staining of endomyocardial biopsies. A total of 105 CA patients (wild-type transthyretin: 74.3%, variant transthyretin: 8.6%, light chain: 17.1%) were analyzed for this study. We detected correlations of total QRS voltage with histologically quantified amyloid burden (r = -0.780, p = 0.039) and ECV (r = -0.266, p = 0.006). In patients above the ECV median (43.9%), PR intervals were significantly longer (p = 0.016) and left anterior fascicular blocks were more prevalent (p = 0.025). In our survival analysis, neither Kaplan-Meier curves (p = 0.996) nor Cox regression analysis detected associations of QRS voltage with adverse patient outcomes (hazard ratio: 0.995, p = 0.265). The present study demonstrated that an increased amyloid burden is associated with lower voltages in CA patients. However, baseline ECG findings, including QRS voltage, were not associated with adverse outcomes.

Assessment of cardiac arrhythmias, P wave and QT dispersion in systemic sclerosis

Cardiac involvement in systemic sclerosis (SSc) is significant cause of SSc-related mortality. The objective of the study was to assess cardiac arrhythmias, P wave and QT dispersion in SSc patients. 40 SSc patients and 40 healthy participants who had similar sociodemographic characteristics with the patients were enrolled in the study. P wave dispersion (Pd), QT dispersion (QTd), and corrected QT (QTc) dispersion (QTcd) were calculated by measuring maximum (max) and minimum (min) of P wave, QT interval, QTc in 12-leads electrocardiography (ECG). Cardiac arrhythmias and conduction disorders were assessed by ECG and Holter-ECG. The mean age of SSc patients (92.5% of females) was 50.9±13.9 years similar with the healthy group (51.4±8.9). Abnormal ECG findings were found in 27.5% of SSc patients and remarkably higher in comparison to the healthy participants (p=0.019). The most frequently reported abnormal ECG findings were left anterior fascicular block (15%), ventricular premature beat (10%) and first-degree atrioventricular heart block (5%). The comparison of dispersion showed no statistically important difference in Pd between two groups (p=0.69) while QTd, QTc, QTcd, QTc min, and QTc max were markedly prolonged in patients with SSc (p=0.039; p&lt;0.001; p=0.021; p&lt;0.001; p&lt;0.001, respectively). The assessment of Holter-ECG demonstrated that supraventricular tachycardia was frequently detected in patients with SSc (22.5% vs 2.5%; p=0.007). This study indicated a significantly elevated incidence of abnormal ECG results and SVT, an arrhythmia not typically identifiable through standard ECG but detectable via Holter monitoring, in patients with SSc. In the study, QTd, QTc, and QTcd intervals were significantly longer in SSc patients, which may indicate a susceptibility to arrhythmias.

Tall R waves in the right precordial leads as a possible expression of left septal fascicular block

Histological, physiological and pathophysiological studies have shown that the left bundle branch mainly divides into three fascicles, and a septal (middle) fascicle is present in over half of human hearts. Electrocardiographic criteria for the diagnosis of the block of this fascicle have been suggested by some authors: tall R waves in lead V2 and sometimes in V1 in the absence of a right bundle branch block pattern or a well evident jump of R waves from V1 to V2, absence of initial septal q waves and/or possible small q waves in the right precordial leads, normal QRS duration and normal QRS axis. At present, this intraventricular block can only be suspected but not diagnosed with certainty even after clinical/instrumental exclusion of pathological situations associated with tall R waves in leads V1 and V2 (right ventricular hypertrophy, lateral infarction, severe septal hypertrophy) because of the marked variability of normal ECG and the potential presence of confounding diseases.

Risk Assessment of Permanent Pacemaker Implantation After Transcatheter Aortic Valve Implantation in Patients With Preexisting Right Bundle Branch Block

Preexisting right bundle branch block (RBBB) is the strongest predictor for permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI). However, the risk assessment for new PPI and effective procedural strategy for preventing new PPI in patients with preexisting RBBB are still unclear. This study stratified the new PPI risk after TAVI and investigated the impact of implantation strategy in a preexisting RBBB cohort. We analyzed 237 patients with preexisting RBBB who underwent TAVI. The primary endpoint was the incidence of new PPI. Multivariate analyses investigating predictors for new PPI were performed. The overall PPI rate was 33.3%. Significant baseline predictors for new PPI were combination of RBBB, left anterior or posterior fascicular block, and first-degree atrioventricular block (odds ratio [OR] 2.55, 95% confidence interval [CI] 1.09 to 5.04), high calcium volume of noncoronary cusp (OR 2.08, 95% CI 1.05 to 4.10), and membranous septum (MS) length <2mm (OR 2.02, 95% CI 1.09 to 3.75) in the univariate analysis and MS length <2mm (OR 2.25, 95% CI 1.06 to 4.82) in the multivariate analysis. On the multivariate analysis including procedural variables, predilatation (OR 2.41, 95% CI 1.01 to 5.83), self-expanding valves (Corevalve, Evolut R, and Evolut Pro/Pro+; Medtronic Inc., Minneapolis, Minnesota) or mechanical expanding valves (Lotus/Lotus Edge; Boston Scientifics, Marlborough, Massachusetts) (OR 3.00, 95% CI 1.31 to 6.91), and implantation depth > MS length (OR 4.27, 95% CI 1.81 to 10.08) were significantly associated with new PPI. The incidence of new PPI increased according to the number of baseline predictors (0: 20.9%, 1: 34.3%, and ≥2: 52.0%) and procedural predictors (0: 3.7%, 1: 20.9%, 2: 40.5%, and 3: 60.0%). New PPI risk in a preexisting RBBB subset could be stratified by baseline factors. Device selection and implantation strategy considering MS length could prevent new PPI even in these high-risk population.

Three-dimensional vector ECG analysis in the diagnosis of the left bundle branch block

The complete left bundle branch block (CLBBB) leads to the development of severe heart failure and requires resynchronization therapy(CRT). It is known that one third of patients do not respond to CRT. In this regard, it is necessary to search new diagnostic criteria for patient selection for CRT.Aim. Determination of the criteria for CLBBB using three-dimensional vectorcardiography data with analysis of the rate of vector loop formation.Material and research methods. The study included 137 patients. The main group consisted of 57 patients with CLBBB, which was based on D. G. Strauss et al. (2011) criteria. Causes of CLBBB and comorbidities were not considered. The control group included 80 healthy individuals. All patients underwent synchronous registration of 12 standard ECG leads and reconstruction of a three-dimensional vectorcardiogram (VCG) using the McFee-Parungao system.Research results. The following signs are characteristic for CLBBB according to three-dimensional VCG data: • fracture of the spatial vector loop due to a change in the direction of the excitation front in its middle part; • reduction in planarity index (PI) less than 80%; • a sharp, by a factor of 2 or more, decrease in the speed of tracing a spatial vector loop in its middle part with the formation of a “claw-shaped” curve with two peaks R and L.Conclusion. Three-dimensional VCG allows you to reliably determine the «true» CLBBB, based on the “fracture” of the spatial vector loop with a reduction in PI less than 80% and a significant decrease in the speed of tracing the vector loop in its middle part with the formation of a “clawshaped” curve and carry out a differential diagnosis with “false” СLBBB, in which changes on the ECG are associated with a combination of left ventricular hypertrophy and left anterior fascicular block, when there is no “fracture” of the loop, a reduction in PI, and the routing speed decreases at the end of the loop without forming a “claw-shaped” curve.

Chagas disease stroke and associated risk factors: A case-control study

Introduction: The intricate relationship between Chagas disease and ischemic stroke remains unclear. Limited evidence exists concerning secondary prophylaxis, etiological diagnosis, and stroke-related determinants. This study aims to discern factors linked to stroke in Chagas disease by contrasting patients with and without a history of ischemic stroke. Methods: Retrospective data from all outpatient Chagas disease patients from two Brazilian hospitals – one Chagas center and one stroke clinic – were examined. Descriptive analyses were conducted to identify stroke-associated factors. Variables were compared between patients with and without ischemic stroke history. Results: Among 678 subjects, 72 had experienced stroke. Univariate associations with stroke included male gender, heart failure, prior or ongoing alcoholism, electrocardiographic features (non-sinus rhythm, left bundle branch, right bundle branch block, left anterosuperior fascicular block, atrial fibrillation), as well as echocardiographic findings indicative of reduced left ventricular ejection fraction and segmental abnormalities. After logistic regression (multivariate analysis), congestive heart failure, right bundle branch block, left anterosuperior divisional block, and atrial fibrillation retained independent associations. Conclusion: In this study, cardiac involvement emerged as the predominant factor correlated with stroke in Chagas disease. While atherosclerosis-related risk factors were prevalent, their influence on ischemic stroke in Chagas disease appeared limited.

Obesity and Cardiac Conduction Block Disease in China

Although a high body mass index (BMI) has been found to be associated with increased risk of cardiac conduction block (CCB) in older adults, no further studies have investigated the association between obesity and CCB in the general population. To investigate the association between obesity and CCB, including its subtypes. This cohort study used data from participants in the Kailuan Study in China (2006-2018) who had completed a physical examination in 2006 (baseline) and had not experienced CCB before baseline. Data analysis was conducted from March to September 2023. Obesity status was defined by BMI in 3 groups: normal weight (18.5 to <24), overweight (24 to <28), and obesity (≥28). The primary outcome was CCB, which was diagnosed from standard 12-lead electrocardiography. The primary end point included high-grade atrioventricular block (HAVB), complete right bundle branch block, complete left bundle branch block, left anterior fascicular block (LAFB), and left posterior fascicular block. First-degree atrioventricular block (FAVB), second-degree type 1 AVB, HAVB, complete and incomplete right and left bundle branch block, LAFB, and left posterior fascicular block were considered separately as secondary end points. Among 86 635 participants (mean [SD] age, 50.8 [11.9] years; 68 205 males [78.7%]), there were 33 259 individuals with normal weight (38.4%), 37 069 individuals with overweight (42.8%), and 16 307 individuals with obesity (18.8%). The mean (SD) follow-up was 10.6 (3.07) years. In the multivariable Cox proportional hazards regression analysis, obesity was associated with an increased risk of incident CCB (hazard ratio [HR], 1.21; 95% CI, 1.04-1.42) vs normal BMI. In secondary analysis, obesity was associated with an increased risk of FAVB (HR, 1.44; 95% CI, 1.21-1.73), HAVB (HR, 1.99; 95% CI, 1.03-3.82), and LAFB (HR, 1.29; 95% CI, 1.03-1.62) vs normal BMI. There was no association between obesity and other CCB subtypes. Obesity was associated with a greater increase in risk of CCB vs normal BMI in older (aged ≥65 years; HR, 1.44; 95% CI, 1.05-1.96) vs younger (aged <65 years; HR, 1.13; 95% CI, 0.96-1.34) participants (P for interaction < .001) and those with diabetes (HR, 2.16; 95% CI, 1.24-3.76) vs without diabetes (HR, 1.19; 95% CI, 1.02-1.39) (P for interaction = .02). This study found that obesity was associated with an increased risk of CCB, with greater increases in risk for FAVB, HAVB, and LAFB. Individuals who were older and those who had diabetes had larger increases in risk.

Incidence and predictors of sudden cardiac arrest in cardiac amyloidosis: a 5-year retrospective analysis

Abstract Background Despite recent advances in treatment, cardiac amyloidosis (CA) portends a poor outcome. Clinical manifestations of CA are variable and often nonspecific, which makes the diagnosis challenging. Failure to recognize early cardiac involvement may result in devastating complications such as sudden cardiac arrest (SCA). Electrocardiography (ECG) is a widely available and affordable modality that can aid with risk stratification. Purpose We aimed to study patient demographics and identify clinical and electrocardiographic (ECG) predictors of SCA in patients with CA. Methods We queried the Nationwide Inpatient Sample database between 2016–2020 to identify hospitalizations for CA who were then subcategorized based on SCA, using the ICD-10 diagnosis code. The primary outcome was to assess clinical and ECG predictors of SCA. Both groups were compared for association using the chi-square test, following which multivariate regression analysis was performed to identify predictors of SCA. In addition, we performed a temporal trends analysis of CA hospitalizations and SCA during this study period. Results A total of 103,620 weighted hospitalizations for CA were identified of which 1935(1.9%) suffered a SCA. Baseline characteristics and comorbidities were largely equivalent except for a history of heart failure which was significantly higher in the SCA group(63.3% vs 46.8%, p &amp;lt; 0.001). Interestingly, traditional cardiac risk factors like smoking, hypertension, diabetes, and obesity did not correlate with increased risk of SCA. African American (AA) race had a higher incidence of SCA(30.2% vs 23.4%, p &amp;lt; 0.001). A multivariate regression analysis was performed to identify predictors of SCA and account for potential clinical as well as demographic confounders. Higher rates of SCA were observed in male sex, age &amp;lt; 40 years, and AA race as outlined in figure 1. The presence of heart failure with reduced ejection fraction (HFrEF), heart failure with preserved ejection fraction (HFpEF), and tachyarrhythmias such as atrial fibrillation, atrial flutter, ventricular tachycardia and ventricular fibrillation were associated with significantly higher odds of SCA. In addition, right bundle branch block, left bundle branch block, first-degree AV block, complete heart block and fascicular blocks were independently predictive of higher rates of SCA. As expected, the rates of ICD implantation were higher in the SCA group (7.2% vs 0.9%, p &amp;lt; 0.001. There is an increasing trend in hospitalizations for cardiac amyloidosis from 2017 to 2020 as highlighted in figure 2. Conclusion Among patients with cardiac amyloidosis, young age, AA race, ECG evidence of AV nodal dysfunction, distal conduction disease, and tachyarrhythmias is associated with an elevated risk of SCA. These findings could improve risk stratification, prompt further targeted evaluation with advanced imaging modalities and help in early identification of amyloid patients with cardiac involvement.Figure 1Figure 2

Abstract 11982: Bariatric Surgery is Associated With Lower Odds of Cardiovascular Diseases and Cardiac Arrhythmias Among Hospitalized Patients With Non-Alcoholic Fatty Liver Diseases: A National Inpatient Sample Study

Introduction: Morbid obesity has shown a strong association with nonalcoholic fatty liver disease (NAFLD), both of which convey significant risk for the development of cardiovascular diseases (CVD). Bariatric surgery (BS) has proved to improve NAFLD and mitigate the severity of different CVD subgroups. Research Question: What are the odds of having different CVDs among morbidly obese patients with NAFLD who have undergone BS compared to those who have not. Methods: Using multivariate logistic regression, national inpatient sample (NIS) databased was analyzed from 2016 to 2019 to compare the odds of having CVD among NAFLD patients who have undergone BS and those who NAFLD patients with no prior BS. Results: The BS and non-BS groups consisted of 27,865 and 315,300 NALFD patients, respectively. BS group was significantly younger with a higher frequency of female patients.The white race, in contrast to the black race, was more frequently in the non-BS group. In addition, Medicare was significantly higher in the non-BS group compared to the BS group. BS was independently associated with lower odds of having HFpEF, HFrEF, AMI, stroke, CAD, peripheral vascular diseases, heart valve diseases, cardiac arrest, cardiogenic shock, AF, VF, VT, RBBB, LBBB, first-, second-, and third-degree heart block, complete heart block, and fascicular block (p-value&lt;0.001 for all). After adjusting for demographics and medical comorbidities, BS was independently associated with 18% lower odds of in-hospital mortality (OR:0.82, CI 95% 0.69-0.97, p-value=0.018). The BS group had a significantly lower length of hospital stay (8.7 days vs. 10 days) (p-value&lt;0.001). Conclusion: Bariatric surgery is associated with significantly lower odds of having cardiovascular diseases in-hospital mortality, and length of stay among hospitalized morbidly obese patients with NAFLD.