Left Posterior Fascicular Block Research Articles

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.

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.

Abstract 13651: Pembrolizumab Associated Myocarditis, Myasthenia Gravis, and Myositis

Case: A 71 year old man presented with acute generalized muscle weakness, double vision, sagging eye lids, weakness with swallowing, shortness of breath, and dark urine. History was notable for stage IV non-small cell lung cancer with second dose of pembrolizumab therapy completed 12 days earlier. Exam showed bilateral ptosis and muffled speech. He had increased work of breathing, tachypnea, 3/5 strength in the bilateral lower extremities, and 5/5 strength in the upper extremities. His initial NIF was -25. Labs were notable for troponin of 1532, CK 16229, ESR 100, CRP 8.8, ALT 225, and AST 648. EKG revealed a new right bundle branch block and left posterior fascicular block. TTE showed EF of 65% without regional wall motion abnormalities. Cardiac MRI showed mildly elevated T1 and T2 relaxation times, suggestive of diffuse myocardial edema and inflammation without delayed gadolinium enhancement. He was treated with high dose steroids, fluid resuscitation, IVIG, and briefly pyridostigmine. On hospital day 8, he was found to have complete AV block with junctional escape rhythm. He had urgent placement of a temporary pacemaker. He was started on abatacept, ruxolitinib, and oral prednisone. Over the next 14 days he made gradual improvement. Discussion: While ICI-associated myocarditis is rare, it is worth investigating due to the high mortality. The clinical presentation can range from asymptomatic troponin elevations to cardiogenic shock and ventricular arrhythmias/AV block. Diagnosis requires a high index of suspicion and multiple diagnostic modalities, including ECG, echocardiography, serum biomarkers, and often cardiac MRI and endomyocardial biopsy. There is a large overlap between myocarditis and myositis. The mainstay treatments of ICI-induced myocarditis include holding the offending immune-checkpoint inhibitor, high-dose corticosteroids, and guideline-directed medical therapy for associated heart failure or arrhythmias. Abatacept, a cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) immunoglobulin fusion protein, and ruxolitinib, a JAK 1/2 inhibitor, have recently been suggested as a novel combination to reduce mortality from ICI-associated myocarditis with concomitant myositis.

Comparison of strategies for catheter ablation of left posterior fascicular ventricular tachycardia.

Traditional ablation strategies including targeting the earliest Purkinje potential (PP) during left posterior fascicular (LPF) ventricular tachycardia (VT) or linear ablation at the middle segment of LPF during sinus rhythm are commonly used for the treatment of LPF-VT. Catheter ablation for LPF-VT targeting fragmented antegrade Purkinje (FAP) potential during sinus rhythm is a novel approach. We aimed to compare safety and efficacy of different ablation strategies (FAP ablation vs. traditional ablation) for the treatment of LPF-VT. Consecutive patients with electrocardiographically documented LPF-VT referred for catheter ablation received either FAP ablation approach or traditional ablation approach. Electrophysiological characteristics, procedural complications, and long-term clinical outcome were assessed. A total of 189 consecutive patients who underwent catheter ablation for LPF-VT were included. Fragmented antegrade Purkinje ablation was attempted in 95 patients, and traditional ablation was attempted in 94 patients. Acute ablation success with elimination of LPF-VT was achieved in all patients. Left posterior fascicular block occurred in 11 of 95 (11.6%) patients in the FAP group compared with 75 of 94 (79.8%) patients in the traditional group (P < 0.001). Fragmented antegrade Purkinje ablation was associated with significant shorter procedure time (94 ± 26 vs. 117 ± 23 min, P = 0.03) and fewer radiofrequency energy applications (4.1 ± 2.4 vs. 6.3 ± 3.5, P = 0.003) compared with the traditional group. One complete atrioventricular block and one left bundle branch block were seen in the traditional group. Over mean follow-up of 65 months, 89 (93.7%) patients in the FAP group and 81 (86.2%) patients in the traditional group remained free of recurrent VT off antiarrhythmic drugs (P = 0.157). Left posterior fascicular-ventricular tachycardia ablation utilizing FAP and traditional ablation approaches resulted in similar acute and long-term procedural outcomes. Serious His-Purkinje injury did occur infrequently during traditional ablation. The use of FAP ablation approach was associated with shorter procedure time and fewer radiofrequency energy applications, especially for non-inducible patients.

Left posterior fascicular block and its relation to mitral valve abnormalities: a forgotten finding

Left posterior fascicular block and its relation to mitral valve abnormalities: a forgotten finding

The Diagnostic Value of the 12-Lead ECG in Arrhythmogenic Left Ventricular Cardiomyopathy: Novel ECG Signs

BackgroundElectrocardiographic (ECG) findings in arrhythmogenic left ventricular cardiomyopathy (ALVC) are limited to small case series. ObjectivesThis study aimed to analyze the ECG characteristics of ALVC patients and to correlate ECG with cardiac magnetic resonance and genotype data. MethodsWe reviewed data of 54 consecutive ALVC patients (32 men, age 39 ± 15 years) and compared them with 84 healthy controls with normal cardiac magnetic resonance. ResultsT-wave inversion was often noted (57.4%), particularly in the inferior and lateral leads. Low QRS voltages in limb leads were observed in 22.2% of patients. The following novel ECG findings were identified: left posterior fascicular block (LPFB) (20.4%), pathological Q waves (33.3%), and a prominent R-wave in V1 with a R/S ratio ≥0.5 (24.1%). The QRS voltages were lower in ALVC compared with controls, particularly in lead I and II. At receiver-operating characteristic analysis, the sum of the R-wave in I to II ≤8 mm (AUC: 0.909; P < 0.0001) and S-wave in V1 plus R-wave in V6 ≤12 mm (AUC: 0.784; P < 0.0001) effectively discriminated ALVC patients from controls. It is noteworthy that 4 of the 8 patients with an apparently normal ECG were recognized by these new signs. Transmural late gadolinium enhancement was associated to LPFB, a R/S ratio ≥0.5 in V1, and inferolateral T-wave inversion, and a ringlike pattern correlated to fragmented QRS, SV1+RV6 ≤12 mm, low QRS voltage, and desmoplakin alterations. ConclusionsPathological Q waves, LPFB, and a prominent R-wave in V1 were common ECG signs in ALVC. An R-wave sum in I to II ≤8 mm and SV1+RV6 ≤12 mm were specific findings for ALVC phenotypes compared with controls.

The pivotal role of ECG in cardiomyopathies.

Cardiomyopathies are a heterogeneous group of pathologies characterized by structural and functional alterations of the heart. Recent technological advances in cardiovascular imaging offer an opportunity for deep phenotypic and etiological definition. Electrocardiogram (ECG) is the first-line diagnostic tool in the evaluation of both asymptomatic and symptomatic individuals. Some electrocardiographic signs are pathognomonic or fall within validated diagnostic criteria of individual cardiomyopathy such as the inverted T waves in right precordial leads (V1-V3) or beyond in individuals with complete pubertal development in the absence of complete right bundle branch block for the diagnosis of arrhythmogenic cardiomyopathy of the right ventricle (ARVC) or the presence of low voltages typically seen in more than 60% of patients with amyloidosis. Most other electrocardiographic findings such as the presence of depolarization changes including QRS fragmentation, the presence of epsilon wave, the presence of reduced or increased voltages as well as alterations in the repolarization phase including the negative T waves in the lateral leads, or the profound inversion of the T waves or downsloping of the ST tract are more non-specific signs which can however raise the clinical suspicion of cardiomyopathy in order to initiate a diagnostic procedure especially using imaging techniques for diagnostic confirmation. Such electrocardiographic alterations not only have a counterpart in imaging investigations such as evidence of late gadolinium enhancement on magnetic resonance imaging, but may also have an important prognostic value once a definite diagnosis has been made. In addition, the presence of electrical stimulus conduction disturbances or advanced atrioventricular blocks that can be seen especially in conditions such as cardiac amyloidosis or sarcoidosis, or the presence of left bundle branch block or posterior fascicular block in dilated or arrhythmogenic left ventricular cardiomyopathies are recognized as a possible expression of advanced pathology. Similarly, the presence of ventricular arrhythmias with typical patterns such as non-sustained or sustained ventricular tachycardia of LBBB morphology in ARVC or non-sustained or sustained ventricular tachycardia with an RBBB morphology (excluding the "fascicular pattern") in arrhythmogenic left ventricle cardiomyopathy could have a significant impact on the course of each disease. It is therefore clear that a learned and careful interpretation of ECG features can raise suspicion of the presence of a cardiomyopathy, identify diagnostic "red flags" useful for orienting the diagnosis toward specific forms, and provide useful tools for risk stratification. The purpose of this review is to emphasize the important role of the ECG in the diagnostic workup, describing the main ECG findings of different cardiomyopathies.

The value of the 12-lead electrocardiogram in the prediction of sudden cardiac death.

Sudden cardiac death (SCD) can be caused by several clinical conditions, overt or misconceived, which recognize different pathophysiologies determining the development of fatal arrhythmic events. In the various forms of structural heart disease such as ischaemic heart disease, cardiomyopathies (e.g. hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy), channelopathies (e.g. long-QT syndrome, congenital short QT, Brugada syndrome, early repolarization (ER) syndrome, and idiopathic ventricular fibrillation) but also in the apparently healthy subject, the 12-lead electrocardiogram (ECG) has proved, over the years, to be a reliable and readily available method for stratifying the risk of adverse arrhythmic events and consequently SCD. Several electrocardiographic markers have been shown to be associated with adverse outcomes in different types of patients. Although with different sensitivity and specificity in each clinical condition, depolarization abnormalities, such as QRS fragmentation, Q waves, QRS duration, left posterior fascicular block, low QRS voltage, and left ventricular hypertrophy and similarly repolarization abnormalities as ER pattern, T wave alternans, QT interval, and QT dispersion, have shown significant efficacy in predicting SCD. Despite the advancement of techniques especially in the field of imaging, the correct interpretation of the 12-lead ECG remains, therefore, an effective tool for assessing the possible prognostic outcome in terms of arrhythmic risk and SCD in different types of patients.

Lifestyle habits associated with cardiac conduction disease.

Cardiac conduction disease can lead to syncope, heart failure, and death. The only available therapy is pacemaker implantation, with no established prevention strategies. Research to identify modifiable risk factors has been scant. Data from the Cardiovascular Health Study, a population-based cohort study of adults ≥ 65 years with annual 12-lead electrocardiograms obtained over 10 years, were utilized to examine relationships between baseline characteristics, including lifestyle habits, and conduction disease. Of 5050 participants (mean age 73 ± 6 years; 52% women), prevalent conduction disease included 257 with first-degree atrioventricular block, 99 with left anterior fascicular block, 9 with left posterior fascicular block, 193 with right bundle branch block (BBB), 76 with left BBB, and 102 with intraventricular block at baseline. After multivariable adjustment, older age, male sex, a larger body mass index, hypertension, and coronary heart disease were associated with a higher prevalence of conduction disease, whereas White race and more physical activity were associated with a lower prevalence. Over a median follow-up on 7 (interquartile range 1-9) years, 1036 developed incident conduction disease. Older age, male sex, a larger BMI, and diabetes were each associated with incident conduction disease. Of lifestyle habits, more physical activity (hazard ratio 0.91, 95% confidence interval 0.84-0.98, P = 0.017) was associated with a reduced risk, while smoking and alcohol did not exhibit a significant association. While some difficult to control comorbidities were associated with conduction disease as expected, a readily modifiable lifestyle factor, physical activity, was associated with a lower risk.

Electrophysiological characteristics and long-term outcome of substrate-based catheter ablation for left posterior fascicular ventricular tachycardia targeting fragmented antegrade Purkinje potentials during sinus rhythm.

The aim of this study was to investigate the electrophysiological characteristics and long-term outcome of patients undergoing substrate-based ablation of left posterior fascicular ventricular tachycardia (LPF-VT) guided by targeting of fragmented antegrade Purkinje potentials (FAPs) during sinus rhythm. This study retrospectively analysed 50 consecutive patients referred for ablation. Substrate mapping during sinus rhythm was performed to identify the FAP that was targeted by ablation. FAPs were recorded in 48 of 50 (96%) patients during sinus rhythm. The distribution of FAPs was located at the proximal segment of posterior septal left ventricle (LV) in two (4.2%) patients, middle segment in 33 (68.8%) patients, and distal segment in 13 (27.1%) patients. In 32 of 48 (66.7%) patients, the FAP displayed a continuous multicomponent fragmented electrogram, while a fragmented, split, and uncoupled electrogram was recorded in 16 (33.3%) patients. Entrainment attempts at FAP region were performed successfully in seven patients, demonstrating concealed fusion and the critical isthmus of LPF-VT. Catheter ablation targeting at the FAPs successfully terminated the LPF-VT in all 48 patients in whom they were seen. Left posterior fascicular (LPF) block occurred in four (8%) patients after ablation. During a median follow-up period of 61.2 ± 16.8 months, 47 of 50 (94%) patients remained free from recurrent LPF-VT. Ablation of LPF-VT targeting FAP during sinus rhythm results in excellent long-term clinical outcome. FAPs were commonly located at the middle segment of posterior septal LV. Region with FAPs during sinus rhythm was predictive of critical site for re-entry.

Impact of bundle branch block morphology on outcomes of patients with syncope and bifascicular block: A SPRITELY (POST 3) substudy

Permanent pacing is often considered for patients with syncope and bifascicular block. The purpose of this study was to determine whether QRS morphology or other electrocardiographic characteristics can identify patients who may benefit from permanent pacing. The Syncope: Pacing or Recording in the Later Years (SPRITELY) trial was a multicenter trial that randomized patients with bifascicular block and syncope (n = 115) to empiric pacemaker implantation vs implantable loop recorder (ILR) monitoring. In this SPRITELY subanalysis, baseline 12-lead electrocardiograms were evaluated for bundle branch block (BBB) morphology, QRS width, and PR and QT intervals and their impact on clinical outcomes was assessed. There were 41 patients with left BBB (36%), 69 patients with right bundle branch block (RBBB) and left anterior fascicular block (60%), and 5 patients with RBBB and left posterior fascicular block (4%). Pacemaker implant compared with ILR was associated with a significant reduction of major study-related events (MSREs) in both patients with left BBB (23.8% vs 78.9%; P = .001) and those with RBBB (27% vs 72.9%; P < .0001). Similarly, a reduction of MSREs was observed in both patients with trifascicular block (23% vs 84.6%; P < .0001) and those with bifascicular block (26.6% vs 68.9%; P = .002). In the group randomized to ILR monitoring, the type of BBB was not a predictor of recurrent syncope (P = .30), bradycardia requiring pacemaker (P = .15), or MSREs (P = .42). The presence ofPR interval prolongation or QRS width in this group did not predict MSREs (P = .22 and P = .96, respectively). In patients with syncope and bifascicular block, pacemaker implantation reduces adverse events as compared with ILR monitoring, irrespective of the type of BBB or the presence of PR interval prolongation.

Prevalence and incidence of intraventricular conduction disturbances among Chinese adults: Results from the Kailuan study.

ObjectivesEpidemiological data on intraventricular conduction disturbances (IVCDs) are limited in the Chinese population. We aimed to investigate the prevalence and incidence of different types of IVCDs among Chinese adults.MethodsFrom June 2006 to October 2007, a total of 100,250 individuals from the Kailuan Study underwent electrocardiogram examinations. Follow-up visits were performed biennially. The prevalence and incidence of right bundle branch block (RBBB), incomplete RBBB (IRBBB), left bundle branch block (LBBB), incomplete LBBB, left anterior fascicular block (LAFB), left posterior fascicular block (LPFB) and non-specific IVCD (NIVCD) were calculated. Their association with risk factors and cardiovascular diseases was also investigated.ResultsThe prevalence and incidence of all IVCDs were 3.19 and 1.70%, respectively. RBBB, IRBBB, and LAFB were the IVCD types that had the highest prevalence and incidence. The prevalence (3.67% vs. 1.29%; P < 0.001) and incidence (1.93% vs. 0.84%; P < 0.001) of IVCDs were higher among males than among females. The prevalence and incidence of most IVCD types increased with age. IRBBB, LBBB, and LAFB were significantly associated with hypertension. LBBB and NIVCD were associated with diabetes mellitus. In addition, LBBB and LAFB were related to prior myocardial infarction.ConclusionIVCDs differ in prevalence and incidence according to sex and age group. They also show disparate associations with other cardiovascular comorbidities. These differences need to be considered in daily clinical practice.

Bundle branch block and nonspecific intraventricular conduction delay prevalence using Chinese nationwide survey data.

ObjectiveWe aimed to determine the prevalence of and the factors associated with intraventricular conduction disturbance in the Chinese population.MethodsElectrocardiographic data from 42,031 people were retrospectively analysed. The weighted prevalences of left bundle branch block (LBBB), right bundle branch block (RBBB), bifascicular block and nonspecific intraventricular conduction delay (NS-IVCD) were calculated. The independently associated factors were determined using logistic regression analysis.ResultsThe weighted prevalence for Chinese people older than 45 years was 0.17% for LBBB, 2.16% for RBBB and 0.44% for NS-IVCD. The weighted prevalence for RBBB combined with left anterior fascicular block was 0.17%, and 0.05% for RBBB combined with left posterior fascicular block. There were significant differences in the weighted prevalences of RBBB and NS-IVCD between men and women. The weighted prevalence of LBBB and RBBB increased markedly with increasing age. Age and diabetes were independent factors associated with LBBB, compared with age and sex for RBBB and sex and coronary artery disease for NS-IVCD.ConclusionsThis study provided reliable data for the weighted prevalence of and factors associated with LBBB, RBBB and NS-IVCD in Chinese adults.

P144 PEMBROLIZUMAB–INDUCED MYOCARDITIS

Abstract Introduction Patients treated with Immunocheckpoint Inhibitors (ICI) can develop adverse cardiovascular events, most frequently myocarditis, but also arrhythmias, conduction abnormalities, pericarditis, Takotsubo syndrome, ACS, heart failure, cardiac arrest. Myocarditis occurs early, within the first 3–4 administrations of therapy, and is fraught with a high mortality rate. Case Presentation 80–year–old patient with renal pelvic carcinoma who underwent nephroureterectomy and subsequent adrenalectomy. Twenty days after the first cycle of Pembrolizumab, the patient is admitted to cardiology for syncope and ECG finding of Left Posterior Fascicular Block (LPFB) and right bundle branch block (RBBB) with significant increase in troponin without any alterations in regional kinetics and normal ventricular function (EF). The patient also complains of widespread muscle pain and severe hyponatremia on blood tests. On ECG monitoring, alternation of RBBB with associated LPFB and Left Posterior Fascicular Block, left bundle branch block, first and second degree atrio–ventricular block (AV block) and on day II appearance of complete paroxysmal AV block controlled with temporary pacemaker implantation. On the 4th day, we documented changes in the segmental motion of the left ventricle (LV) and progressive gradual worsening of the EF. During the hospitalization the patient manifested episodes of general malaise with profuse sweating and marked hypotension with possible SIADH picture. In suspicion of acute myocarditis, peripheral myositis and possible Pembrolizumab SIADH, the patient was treated with high dose methylprednisolone (1000 mg / day) with little benefit. On the 6th day the patient was found in critical condition, severely suffering, hypotensive and oliguric, resigned herself. Conclusions Our case highlights how even a single dose of Pembrolizumab can trigger an acute inflammatory pattern affecting the myocardium with prevalent involvement of the conduction tissue even before the appearance of alterations in the kinetics and ventricular dysfunction. During ICI therapy cycles it is therefore important to monitor the ECG and troponin levels in order to be able to diagnose myocardial involvement early. In fact, although this complication is rare, it is burdened by a high mortality rate. The only treatment currently available involves the suspension of immunotherapy and the administration of high–dose methylprednisolone.

PO-672-06 SIMULTANEOUS HIS BUNDLE, LATERAL LV AND LATERAL RV PACING IN A PATIENT WITH REPAIRED TETRALOGY OF FALLOT

Patients with repaired Tetralogy of Fallot (ToF), who have RBBB and predominant right ventricular (RV) dysfunction may benefit from RV electromechanical resynchronization. We describe the case of a patient with repaired ToF, biventricular (BiV) dysfunction and ineffective cardiac resynchronization therapy (CRT) in whom His bundle pacing (HBP) fused with RV wall pacing achieved RV CRT and acute hemodynamic improvement. N/A 58 YOF with repaired ToF and BiV dysfunction presented with decompensated heart failure (HF). BiV implantable cardioverter-defibrillator (ICD) with RA, RV and coronary sinus (CS) leads (Biotronik, Berlin, Germany) was placed at an outside facility one year ago. Underlying EKG showed sinus rhythm with 1stdegree AVB (PR 240 ms), RBBB (QRSd 200ms) and left posterior fascicular block. With presenting CRT, QRS was wider (QRSd 240). Chest Xray revealed RV ICD lead in the right ventricular outflow tract (RVOT) and the CS lead in the anterior interventricular vein with the tip electrode also near RVOT. Given concern for suboptimal CRT, defibrillation vector and limited alternative options, we pursued individualized CRT optimization. Activation mapping showed latest RV activation in the basal lateral tricuspid annulus. Pacing from this site simultaneously with the His Bundle narrowed the QRS significantly and improved RVEF and dyssynchrony on intracardiac echocardiography. Fick cardiac output and index improved to 4.4 and 2.4 respectively from 3.7 and 2.0 at baseline. Thus, we removed the old CS lead and replaced the ICD lead with a new DF-1 defibrillator lead (Medtronic, Minneapolis, MN) in the RV apical septum. Then, we placed a SelectSecureTM His lead (3830 model, Medtronic, Minneapolis, MN). Non-selective His capture threshold was 1.0 V at 0.4 ms. Then, we placed a SelectSecureTM lead (3830 model, Medtronic, Minneapolis, MN) in the RV basal lateral wall and this was Y-adapted to a new LV lead (4196Y model, Medtronic, Minneapolis, MN) which was placed on a lateral branch of the CS. HBP fused with LV and RV lateral wall pacing resulted in a QRS of 120ms. At one year follow up, she has not had HF admissions. Simultaneous HBP and RV basal lateral wall pacing may be a feasible strategy for RV CRT in patients with ToF, RBBB and predominant RV dysfunction.

Fascicular heart blocks and risk of adverse cardiovascular outcomes: Results from a large primary care population.

Fascicular heart blocks can progress to complete heart blocks, but this risk has not been evaluated in a large general population. The purpose of this study was to investigate the association between various types of fascicular blocks diagnosed by electrocardiographic (ECG) readings and the risk of incident higher degree atrioventricular block (AVB), syncope, pacemaker implantation, and death. We studied primary care patients referred for ECG recording between 2001 and 2015. Cox regression models were used to estimate hazard ratios (HRs) as well as absolute risks of cardiovascular outcomes. Of 358,958 primary care patients (median age 54 years; 55% women), 13,636 (3.8%) had any type of fascicular block. Patients were followed up to 15.9 years. We found increasing HRs of incident syncope, pacemaker implantation, and third-degree AVB with increasing complexity of fascicular block. Compared with no block, isolated left anterior fascicular block (LAFB) was associated with 0%-2% increased 10-year risk of developing third-degree AVB (HR 1.6; 95% confidence interval [CI] 1.25-2.05), whereas right bundle branch block combined with LAFB and first-degree AVB was associated with up to 23% increased 10-year risk (HR 11.0; 95% CI 7.7-15.7), depending on age and sex group. Except for left posterior fascicular block (HR 2.09; 95% CI 1.87-2.32), we did not find any relevant associations between fascicular block and death. We found that higher degrees of fascicular blocks were associated with increasing risk of syncope, pacemaker implantation, and complete heart block, but the association with death was negligible.

A rare combination of atrial and intraventricular conduction disturbances: Atypical type I advanced interatrial block, left posterior fascicular block and transient right bundle branch block

According to the first 2012 consensus report about interatrial block, the diagnosis of advanced interatrial block (A-IAB) consists of a P-wave duration ≥120 ms with biphasic “plus-minus” (±) polarity in the three leads of the inferior wall in the electrocardiogram. At the end of 2018, a new concept was introduced: the atypical A-IAB due to changes in the polarity or duration of the P-wave. The prevalence of these atypical patterns in different scenarios is currently unknown, but the patterns should be considered as risk factors of embolic stroke of undetermined source. When the A-IAB pattern is associated with clinical arrhythmic manifestations, it is known as the Bayés' Syndrome.We present a characteristic case of atypical A-IAB, and the rare left posterior fascicular block and transient right bundle branch block.

Report of a new case of saw-tooth cardiomyopathy: Clinical presentation and genetic analysis

Saw-tooth Cardiomyopathy is a very rare disease, that should not be confused with left ventricular non compaction, and only few cases have been described. We describe the case of a 33-year-old man who presented with atypical chest pain. The ECG showed left posterior fascicular block. Left ventricular non-compaction (LVNC) was initially suspected by echocardiography. Cardiac MRI found no criteria for LVNC but typical protrusions of muscular bridges in the left ventricle with dense compacted myocardium leading to the diagnosis of Saw-Tooth Cardiomyopathy. No arrhythmic event nor heart failure were noticed. In the family there was no cardiac history nor sudden death. We performed genetic analysis by sequencing a large panel of 71 genes associated with cardiomyopathies [Roche Nimblegen capture probes, sequencing on Miseq (Illumina)]. No pathogenic variant was found according to ACMG criteria ( Fig. 1 ). Less than ten cases of Saw-Tooth Cardiomyopathy (ST-CMP) were previously reported in literature and ST-CMP was initially reported as a variant of LVNC. In fact, myocardial features of ST-CMP are very different from LVNC and ST-CMP should be considered as a separate entity. Some cases were discovered during infancy suggesting prenatal development. Our case first illustrates this distinct entity since none of LVNC criteria were met but typical Saw-tooth muscular bridges that were better exhibited on MRI. Second, our case is the first to report on genetic testing and familial investigations. We did not observed other cardiomyopathy in the family and we did not identify any pathogenic mutation in known cardiomyopathy genes. Although we cannot exclude a non-genetic cause, this result may suggest a genetic cause outside the genes usually related to cardiomyopathies and suggest the search for a new gene through exome or genome sequencing.

Progressive involvement of cardiac conduction system in paediatric patients with Kearns-Sayre syndrome: how to predict occurrence of complete heart block and sudden cardiac death?

The aims of this study are to evaluate the progressive involvement of the cardiac conduction system in the Kearn-Sayre syndrome (KSS) and to establish criteria for the prevention of episodes of syncope or sudden cardiac death. This is a prospective monocentric study including KSS patients, with diagnosis based on clinical manifestations, muscle biopsy, and genetic tests, before the age of 18. All patients underwent cardiac screening examination with 12-lead electrocardiogram (ECG), 24-h Holter monitoring, and pacemaker (PM) interrogation twice a year. Fifteen patients (nine males, mean age 16.6 ± 3.9 years) with a sporadic KSS were recruited. All subjects manifested at least one of the intraventricular conduction defects (IVDs): 1 right bundle branch block (RBBB), 2 left anterior fascicular block (LAFB), 11 a bi-fascicular block (RBBB + LAFB), and 1 left posterior fascicular block. Most children with bi-fascicular block developed LAFB before the RBBB (P = 0.0049). In six patients, IVD degenerated into atrioventricular block (AVB). Endocavitary PM was implanted in 11 patients (6 with AVB and 5 with a bi-fascicular block), while an implantable cardioverter-defibrillator only in one patient with a non-sustained ventricular tachycardia. Four died at mean age of 14.7 ± 2.6 years, but none of them suddenly. Even a 'simple' ECG can predict the arrhythmic risk and the occurrence of catastrophic events in young patients with KSS. Left anterior fascicular block precedes RBBB in determining the bi-fascicular block and this can predict an inexorable progression of the conduction defects even in a short time. Pacemaker implantation may be indicated in these patients since the first bi-fascicular block manifestation.

Pacemaker and conduction disturbances in patients with atrial septal defect.

To determine the prevalence of pacemaker and conduction disturbances in patients with atrial septal defects. All patients with an atrial septal defect born before 1994 were identified in the Danish National Patient Registry, and 297 patients were analysed for atrioventricular block, bradycardia, right bundle branch block, left anterior fascicular block, left posterior fascicular block, pacemaker, and mortality. Our results were compared with pre-existing data from a healthy background population. Further, outcomes were compared between patients with open atrial septal defects and atrial septal defects closed by surgery or transcatheter. Most frequent findings were incomplete right bundle branch block (40.1%), left anterior fascicular block (3.7%), atrioventricular block (3.7%), and pacemaker (3.7%). Average age at pacemaker implantation was 32 years. Patients with defects closed surgically or by transcatheter had an increased prevalence of atrioventricular block (p < 0.01), incomplete right bundle branch block (p < 0.01), and left anterior fascicular block (p = 0.02) when compared to patients with unclosed atrial septal defects. At age above 25 years, there was a considerably higher prevalence of atrioventricular block (9.4% versus 0.1%) and complete right bundle branch block (1.9% versus 0.4%) when compared to the background cohorts. Patients with atrial septal defects have a considerably higher prevalence of conduction abnormalities when compared to the background population. Patients with surgically or transcatheter closed atrial septal defects demonstrated a higher demand for pacemaker and a higher prevalence of atrioventricular block, incomplete right bundle branch block, and left anterior fascicular block when compared to patients with unclosed atrial septal defects.