Bundle Branch Block Pattern Research Articles

Mid-term follow-up of atrioventricular node ablation and conduction system pacing without a ventricular backup lead in atrial fibrillation-induced tachycardiomyopathy - a single-center experience

Abstract Funding Acknowledgements Type of funding sources: None. In the permanent form of atrial fibrillation (AF), ablation is not recommended or has failed and the only option is rate control. The most effective rate control strategy is atrioventricular node (AVN) ablation, but this renders the patient pacing-dependent. Several observational studies have shown that both His bundle pacing (HBP) and left bundle branch area pacing (LBBAP), provide a narrower QRS complex and a more synchronous ventricular activation compared to right ventricular pacing. Current guidelines recommend placing a ventricular backup lead as a safety measure. We present our mid-term follow-up data on the feasibility of AVN ablation and physiological pacing without a ventricular backup lead in patients with tachycardiomyopathy due to rapidly conducted permanent AF. MATERIAL AND METHODS A total of 25 patients with permanent AF and HF and rate control failure with AVN-blocking drugs, that underwent physiological pacing and AVN ablation at our institution, were included in this retrospective review. During the procedure, HBP was the first option, followed by LBBAP if the His bundle was not captured at a threshold below 2.5V at 1 ms. The lead was connected to a single chamber pacemaker, without a backup pacing lead. In the same setting, using a femoral vein approach, a 4-mm tip ablation catheter was used to perform AVN ablation. Patient and procedural characteristics were recorded as well as the electrical parameters and complications at the follow-up visits. Results The mean age of the patients was 69 ± 12.4 years and 64% were males. The heart rate was 133±20.43 bpm and the ejection fraction was 28.84±9.02 %. 17 patients had normal QRS complex, 3 had right bundle branch block and 5 had left bundle branch block patterns. HBP was successful in 9 patients (36%) and LBBAP in 16 patients (64%). In patients with a baseline-wide QRS, physiological pacing significantly reduced the QRS duration (135.25±17.58 vs. 159±32.38 ms, p=0.04). The paced QRS complex was significantly narrower in HBP than LBBAP (95.67±14.37 vs. 129.88±17.46 ms, p<0.001). There was a significantly lower pacing threshold for LBBAP (0.77±0.3 V at 1 ms vs. 0.87±0.72 V at 0.4 ms, p<0.05) and better sensitivity for LBBAP (6.23±4.56 mV vs. 10.2±5.19 mV, p=0.66). The fluoroscopy time was non-statistically different between HBP and LBBAP (13.21±15.47 min vs. 18.72±12.95 min, p=0.35). AV node ablation was successful in all patients. The mean follow-up period was 524±110.2 days. 11 patients became pacemaker-dependent. There was no significant difference in pacing thresholds for both LBBAP (0.67±0.27 V at 0.4 ms, p=0.24) and HBP (0.87±0.56 V at 1 ms, p=0.485) patients and there was no recurrence in AV node conduction. No lead dislodgements were recorded. Conclusions AVN ablation and physiological pacing is feasible and safe without the need for a backup ventricular pacing lead, thus minimizing the risks and costs associated with a higher lead burden.

Usefulness of the synthesized 18-lead ECG in premature ventricular contractions from near the HIS bundle.

Isolated premature ventricular complexes (PVCs) are the most common arrhythmias observed in patients even if without structural heart disease.1 Although most PVCs originate from the right ventricular outflow tract (RVOT), there are some PVCs that originate near the HIS bundle.2 The synthesized 18-lead ECG consists of right-sided thoracic (V3R, V4R, V5R) and dorsal (V7, V8, V9) ECG leads derived from a mathematical calculation of the 12-lead ECG, and the detailed mathematical formula is shown in Figure 1. The synthesized 18-lead ECG has been reported to be effective for PVCs of an RVOT origin, but the rest remains to be elucidated.3 The aim of this study was to investigate the characteristics of the synthesized 18-lead ECG in patients with PVCs originating from near the HIS bundle. The synthesized 18-lead ECGs of 13 consecutive patients who underwent radiofrequency catheter ablation (RFCA) of idiopathic PVCs from near the HIS bundle at the Japan Community Healthcare Organization Osaka Hospital, Osaka General Medical Center, and Nara Prefectural Seiwa Medical Center from January 2018 to December 2020 were included in this retrospective analysis. The origin of the PVCs was identified by a cardiologist using a 3D mapping system (CARTO 3: Biosense Webster Inc or EnSite: Abbott Medical Inc). We analyzed the QRS morphology pattern of the synthesized 18-lead ECG analyzed in those patients. This study was approved by the Ethics Committee of each hospital in accordance with the Declaration of Helsinki. The synthesized 18-lead ECG and ECG characteristics in 13 patients with PVCs from near the HIS bundle are shown in Figure 2 and Table 1. The mean QRS duration of the ECG was 142.5 ± 26.9 ms. In 12 of 13 patients, a left bundle branch block pattern (92.3%) was present, and 11 of 13 patients had inferior axis deviation (84.6%). Regarding the right-sided chest leads of the synthesized 18-lead ECG, in all patients, a QS pattern in lead V5R (100%) was observed, and in 12 of 13 patients, a QS pattern in leads V3R, V4R, and V5R (92.3%) was present. A comparison showed that the synthesized ECGs recorded during sinus rhythm and during PVCs were not consistent, as shown in Table 2. Several studies have shown that identifying PVCs originating from the vicinity of the ventricular septum remains complicated,4 and it is difficult to identify the origin of PVCs originating from near the HIS bundle based on the characteristics of the 12-lead ECG. Noteworthy among our results was that there was a QS pattern in lead V5R in 100.0%. Igarashi et al reported that in the synthesized 18-lead ECG recorded by pace mapping in the outflow tract, a QS pattern in lead V5R was observed in about 80% at the right coronary cusp (RCC), about 20% in the posterior RVOT, and nothing at the other sites.3 Combining the above study3 with our results, a QS pattern in lead V5R might have been specific to PVCs originating from near the HIS bundle and RCC. QRS morphology changes after RFCA are often observed in patients with idiopathic PVCs.5 In such cases, the use of the synthesized 18-lead ECG's right-sided chest leads may assist in the re-mapping process. Regarding the mechanism of the QS pattern in lead V5R, in general the HIS bundle is anatomically closer to the RCC, and electrical conduction may propagate with a vector away from the right-sided chest leads such as lead V5R. Based on the characteristics of the ECG, only case 7 was considered to have a PVC from the HIS bundle. An identification of PVCs originating from near the HIS bundle or from the HIS bundle was attempted based on the characteristics of the synthesized ECG, but was not possible due to an insufficient number of cases. Although a 3D mapping system was used in this study, the distance between the HIS bundle and the ablation site was not measured, and it was considered necessary to include the distance in future studies. A QS pattern recorded in lead V5R of the synthesized 18-lead ECG was characteristic of PVCs originating from near the HIS bundle. This observation might assist in identifying the origin of PVCs during RFCA. H Kida, R Nakanishi, and N Ogasawara participated in the design of the study and coordination and helped draft the manuscript. All authors read and approved the final manuscript. We would like to express our gratitude to Mr. John Martin for his linguistic revision of the manuscript. All authors declare no conflicts of interest associated with this manuscript. This study was approved by the Ethics Committee of Japan Community Healthcare Organization Osaka Hospital, Osaka General Medical Center, and Nara Prefectural Seiwa Medical Center in accordance with the Declaration of Helsinki. Since this study was a retrospective study, we used the opt-out system according to the ethics guidelines on human medical research by the Japanese government.

Electrocardiographic and electrophysiological characteristics of ventricular arrhythmias from the right bundle branch of the moderator band

There are little data on ventricular arrhythmias (VAs) originating from the right bundle branch (RBB) of the moderator band (MB) (MB-RBB VAs) in a cohort of patients. The purpose of this study was to investigate the electrocardiographic and electrophysiological characteristics of MB-RBB VAs. Sixteen patients with MB-RBB VAs and 5 patients with right ventricular (RV) anterior papillary muscle (APM) VAs (RV-APM VAs) were studied under the guidance of intracardiac echocardiography. The MB-RBB VAs group demonstrated a typical left bundle branch block pattern with left superior axis deviation and a narrower QRS complex during VAs (P < .001) as compared with the RV-APM VAs group. Furthermore, the MB-RBB VAs group had a shorter rS interval, a sharper slope of the S wave downstroke without notching in leads V1 and V2, and a shorter r wave duration in lead V2. A leading RBB potential at the target during VAs was observed for all patients in the MB-RBB VAs group, which was also present during sinus rhythm for all patients, except for 2 with RBB block at baseline. Ablation of the leading RBB potential effectively eliminated the arrhythmia. In the RV-APM VAs group, no Purkinje potential at the target was identified in any patient during VAs. QRS morphology of MB-RBB VAs is characterized by a typical left bundle branch block pattern with a relatively narrow QRS complex, short r wave and rS durations, and a sharp S wave downstroke without notching in leads V1 and V2. Mapping and ablation of the leading RBB potential are effective in eliminating VAs.

Evaluation of Arrhythmia Prevalence, Management, and Risk Factors in Patients with Transcatheter and Surgically Closed Secundum Atrial Septal Defects.

Atrial septal defect (ASD) accounts for 6-10% of all congenital heart disorders. Secundum ASD closure can be performed surgically or percutaneously. We aimed to identify the various arrhythmias that occur before, during, and after the procedure and evaluate their management. The study included a total of 427 patients aged 0-18 years who underwent transcatheter or surgical closure of isolated secundum ASD between January 2008 and January 2020. Postoperative electrocardiogram (ECG) traces, intraoperative arrhythmias, and treatments were recorded for both groups. Echocardiography and ECG were evaluated at postoperative 1 week, 1, 3, and 6 months, and annually thereafter. After transcatheter closure, follow-up basal ECG showed incomplete right bundle branch block pattern in 21 patients and sinus rhythm in 229 patients. After surgical closure, incomplete right bundle branch block pattern was detected in 23 patients, complete right bundle branch block in 3 patients, and complete AV-block (Atrioventricular Block) pattern in 1 patient. The other 150 patients showed sinus rhythm. At least one postoperative follow-up Holter ECG record could be obtained for 104 patients in the transcatheter group and 96 patients in the surgical group. Of 104 patients who underwent transcatheter closure, 97 (93.3%) had normal Holter ECG findings and 7 (6.7%) had arrhythmia. Of the 96 patients who underwent surgical closure, 85 (88.5%) had normal Holter ECG traces and 11 (11.5%) had arrhythmia. There was no statistically significant difference in the frequency of arrhythmia (P = 0.164). The higher frequency of arrhythmia in adult studies compared to the pediatric age group once again demonstrates the importance of early diagnosis and treatment of ASD in childhood. The similar incidence of arrhythmia in both groups supports the safety and effectiveness of both closure methods in eligible patients.

Right bundle branch block and SIQIII-type patterns for risk stratification in acute pulmonary embolism

Right bundle branch block and SIQIII-type patterns for risk stratification in acute pulmonary embolism

Exploratory use of intraprocedural transesophageal echocardiography to guide implantation of the leadless pacemaker.

Fluoroscopy is the standard tool for transvenous implantation of traditional and leadless pacemakers (LPs). LPs are used to avoid complications of conventional pacemakers, but there still is a 6.5% risk of major complications. Mid-right ventricular (RV) septal device implantation is suggested to decrease the risk, but helpful cardiac landmarks cannot be visualized under fluoroscopy. Transesophageal echocardiography (TEE) is an alternative intraprocedural imaging method. The purpose of this study was to explore the spatial relationship of the LP to cardiac landmarks via TEE and their correlations with electrocardiographic (ECG) parameters, and to outline an intraprocedural method to confirm mid-RV nonapical lead positioning. Fifty-six patients undergoing implantation of LP with TEE guidance were enrolled in the study. Device position was evaluated by fluoroscopy, ECG, and TEE. Distances between the device and cardiac landmarks were measured by TEE and analyzed with ECG parameters with and without RV pacing. Mid-RV septal positioning was achieved in all patients. TEE transgastric view (0°-40°/90°-130°) was the optimal view for visualizing device position. Mean tricuspid valve-LP distance was 4.9 ± 0.9 cm, mean pulmonary valve-LP distance was 4.2 ± 1 cm, and calculated RV apex-LP distance was 2.9 ± 1 cm. Mean LP paced QRS width was 160.8 ± 28 ms and increased from 117.2 ± 34 ms at baseline. LP RV pacing resulted in left bundle branch block pattern on ECG and 37.8% QRS widening by 43.5 ± 29 ms. TEE may guide LP implantation in the nonapical mid-RV position. Further studies are required to establish whether this technique reduces implant complications compared with conventional fluoroscopy.

Cardiopulmonary capacity is reduced in children with ventricular arrhythmia

Premature ventricular contractions (PVCs) are frequently seen in children and are considered benign. A substantial group of adolescents with PVCs complain about a broad range of clinical symptoms, including low exertion tolerance. The purpose of this study was to evaluate prospectively whether ventricular arrhythmia affects physical performance in adolescents with normal left ventricular function, using a cardiopulmonary exercise test (CPET) and evaluating the electrocardiographic (ECG) characteristics of patients with PVCs with regard to exercise capacity. The study group consisted of 49 children with PVCs and normal left ventricular function. The control group consisted of 36 healthy volunteers. Standard ECG, 24-hour Holter ECG, and CPET were performed. PVCs were analyzed for QRS duration, bundle branch block pattern, QRS axis, and coupling interval (CInt). ForCPET, heart rate (HR), oxygen uptake (VO2max), predicted VO2max, and VO2max expressed as a percentage of the predicted value (%VO2) were measured. In 37 patients (76%), arrhythmia subsided during exercise. Patients achieved lower VO2max (32.9 ± 6.3 mL/min/kg) than controls (40.4 ± 6.7 mL/min/kg; P <.01). %VO2 was 71.0 ± 13.7 in patients and 79.3 ± 12.2 in controls (P <.01). Exercise HR at which PVCs subsided correlated with VO2max (r = 0.3; P = .07). Patients with persisting arrhythmia performed worse than those in whom arrhythmia subsided during exercise (VO2max, P<.01; %VO2,P <.01). No correlation between QRS and CInt parameters and VO2max was observed. Patients with PVCs have lower aerobic capacity than their healthy peers. Further worsening of exercise capacity is present when PVCs are preserved during effort.

The Primary Alteration of Ventricular Myocardium Conduction: The Significant Determinant of Left Bundle Branch Block Pattern.

Intraventricular conduction disturbances (IVCD) are currently generally accepted as ECG diagnostic categories. They are characterized by defined QRS complex patterns that reflect the abnormalities in the intraventricular sequence of activation that can be caused by pathology in the His-Purkinje conduction system (HP) or ventricular myocardium. However, the current understanding of the IVCD's underlying mechanism is mostly attributed to HP structural or functional alterations. The involvement of the working ventricular myocardium is only marginally mentioned or not considered. This opinion paper is focused on the alterations of the ventricular working myocardium leading to the most frequent IVCD pattern-the left bundle branch block pattern (LBBB). Recognizing the underlying mechanisms of the LBBB patterns and the involvement of the ventricular working myocardium is of utmost clinical importance, considering a patient's prognosis and indication for cardiac resynchronization therapy.

317 IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR IN ARRHYTMIC MITRAL VALVE PROLAPSE: YOU'LL BE CONSIDER IT FOR PRIMARY PREVENTION OF SUDDEN CARDIAC DEATH?

Abstract A 50-year-old female with a history of bileaflet mitral valve prolapse (MVP) was admitted to our Department for persistent palpitation. Physical examination revealed a mid-systolic click, followed by a mid-to-late apical systolic murmur. The electrocardiogram showed sinus rhythm with negative T-waves in inferior leads and repetitive polymorphic premature ventricular contractions (PVCs) with a right bundle branch block pattern and superior axis morphology suggestive of a possible origin from the posterior papillary muscle. The echocardiography confirmed normal ventricular ejection fraction, bileaflet MVP with moderate regurgitation, systolic curling and mitral annulus disjunction. Exercise stress testing demonstrated an increase of polymorphic PVCs during maximum effort. The cardiac magnetic resonance showed an underlying late gadolinium enhancement at the level of the papillary muscles and in the inferobasal region. After a multidisciplinary evaluation, a transvenous implatable cardioverter defibrillator (ICD) was implanted for primary prevention without clear indications deriving from current guidelines. After eleven years, the patients experienced two appropriate shocks due to polymorfic ventricular tachycardia while she was sleeping. Furthermore, the patient underwent successful mechanical transvenous lead extraction and ICD re-implantation for lead failure. During this hospitalization a subsequent echocardiography detected severe ventricular dilatation with moderate systolic disfunction. Conclusion Our report demonstrated that MVP represents potentially cause of life-threatening ventricular arrhythmias and tachycardia induced cardiomyopathy. Beta-blockers are often inadequate in order to reduce PVCs burden. We need more arrhytmic predictors to assestment of sudden cardiac death risk and evaluate ICD for primary prevention. Obtain left ventricular function recovery is difficult and it requires a multidisciplinary approach. It will be important in the future to better define the role will play cathether ablation and mitral valve repair or replacement to prevent malignant arrhytmias.

Early and mid-term outcomes of transcatheter closure of perimembranous ventricular septal defects using the Lifetech™ Konar-MF Occluder device (MFO).

Transcatheter closure of perimembranous ventricular septal defects is challenging. Double disk-designed devices have high adverse event rates; therefore, research into new devices persists. One such devise is the LifetechTM Konar-MF Occluder device (MFO), which is increasingly used. The purpose of this study is to present mid-term results of MFO for transcatheter closure of patients with perimembraneous ventricular septal defect. Records of the 52 patients with perimembraneous ventricular septal defect who had undergone transcatheter closure with MFO were reviewed. Demographic, echocardiographic, and procedure details were investigated. Three years follow-up results were recorded. We closed the perimembraneous ventricular septal defect in 51 of 52 patients (98%). The femoral venous approach was used in 27 patients (53 %) whilst no arteriovenous loop was established in the remaining patients. No significant procedure-related complication occurred. On day 1 echocardiography, the residual ventricular septal defect rate was 31%. Mean±SD (range) follow-up duration was 36 ± 7,9 (18-54) months. In the follow-up, at 6th months, only four patients had hemodynamically insignificant residual defects. No severe dysrhythmia was detected including complete heart block. A right bundle branch block pattern was seen in one patient. This study showed that MFO is a safe and effective device in the transcatheter treatment of perimembraneous ventricular septal defect's with mid-term follow-up.

Terminal end of retro-aortic root branch: An unrecognized origin for "proximal left anterior fascicle" premature ventricular complexes with narrow QRS duration.

Premature ventricular complexes (PVCs) with narrow QRS duration, inferior frontal plane QRS axis, and right bundle branch block (RBBB) pattern generally originate from the proximal segment of the left anterior fascicle (LAF). The purpose of this study was to investigate the exact origin of this category of PVCs. Twenty-two patients with assumed proximal LAF-PVCs were enrolled in the study. Detailed mapping of fascicular potentials (FPs) was performed during sinus rhythm (SR) and PVCs. During SR, a cluster of FPs could be found at the most superior portion of the left ventricle (LV). These FPs represented the terminal end of a discrete branch of the left fascicular system, which we named the "retro-aortic root branch" (RARB). The shortest distance between the proximal LAF and the terminal end of the RARB was 13.5 ± 4.2 mm. The earliest activation site (EAS) of PVCs in all patients were confirmed at the terminal end of the RARB, where the FP-V interval was 35.1 ± 4.3 ms during PVCs. The shortest distance from the right coronary cusp (RCC) to the EAS was 5.3 ± 3.5 mm. PVCs could be eliminated by ablation from the RCC in 45.5% (10/22) cases, in the remaining cases, ablation at the EAS in the LV endocardium successfully abolished PVCs. The terminal end of the retro-aortic root branch was the actual origin site for PVCs with inferior frontal plane axis, RBBB pattern and narrow QRS duration. Ablation in the RCC or at the EAS in the LV could both eliminate PVCs safely with high efficacy.

The R-S difference index: A new electrocardiographic method for differentiating idiopathic premature ventricular contractions originating from the left and right ventricular outflow tracts presenting a left bundle branch block pattern.

Introduction: Differentiating idiopathic premature ventricular contractions (PVCs) originating from the right and left ventricular outflow tracts with a left bundle branch block (LBBB) morphology is relevant to catheter ablation planning and important for lowering the risk of complications. This study established a novel electrocardiographic (ECG) criterion to discriminate PVCs originating from the septum of the right ventricular outflow tract (s-RVOT) and those originating from the aortic sinus cusp of the left ventricular outflow tract (LVOT-ASC). Methods: A total of 259 patients with idiopathic PVCs originating from ventricular outflow tract with a LBBB pattern who underwent successful catheter ablation were retrospectively included. Among them, the PVCs originated from the s-RVOT in 183 patients and from the LVOT-ASC in 76 patients. The surface ECGs of the PVCs and sinus beats were analyzed using an electronic caliper. The R-S difference index in the precordial leads was calculated as V2R + V3R + V4R − V1S. Results: PVCs originating from both the s-RVOT and LVOT-ASC displayed an inferior axis (dominant R waves in leads II, III, and aVF). Compared with the s-RVOT group, the R-wave amplitudes on leads II, III, and aVF were significantly larger in the LVOT-ASC group (p < 0.001, p < 0.003, and p < 0.001, respectively). Compared to the LVOT-ASC group, the s-RVOT group showed smaller R-wave amplitudes on leads V1–V6 (p = 0.021, p < 0.001, p < 0.001, p < 0.001, p < 0.001, and p < 0.001, respectively) and larger S-wave amplitudes on leads V1–V3 (p < 0.001, p < 0.001, and p < 0.001, respectively). Lead V3 was the most common transitional lead in both groups. Analysis of the receiver operating characteristic curve showed that the R-wave amplitude on lead V3 had the largest area under the curve (AUC) of 0.856 followed by the R-wave amplitudes on leads V4 (0.834) and V2 (0.806). The AUC of the R-S difference index was 0.867. An R-S difference index greater than 20.9 predicted an LVOT-ASC origin with 73.7% sensitivity and 86.3% specificity. This index is superior to previous criteria in differentiating PVCs with LBBB morphology and inferior axis originating from s-RVOT vs. LVOT-ASC. Conclusions: The R-S difference index in precordial leads is a useful new ECG criterion for distinguishing LVOT-PVCs from RVOT-PVCs with LBBB morphology.

Cardiac resynchronization considerations in left bundle branch block.

Cardiac resynchronization therapy (CRT) via biventricular pacing (BiVP) is an established treatment for patients with left ventricular systolic heart failure and intraventricular conduction delay resulting in wide QRS. Seminal trials demonstrating mortality benefit from CRT were conducted in patients with wide left bundle branch block (LBBB) pattern on electrocardiogram (ECG) and evidence of clinical heart failure. The presence of conduction block was assumed to correlate with commonly applied criteria for LBBB. More recent data has challenged this assertion, revealing that LBBB pattern may include distinct underlying pathophysiology, including patients with complete conduction block, either at the left-sided His fibers or the proximal left bundle, intact Purkinje activation with wide LBBB-like QRS, and patients demonstrating both proximal block and distal delay. Currently, BiVP-CRT is indicated for all QRS duration ≥150 ms and may be considered for BBB patterns from 130 to 149 ms with robust clinical data to support its use. Despite this, however, there remains a significant number of non-responders to BVP. Conduction system pacing (CSP) has emerged as an alternative approach to deliver CRT and correct QRS in patients with conduction block. Newer hybrid approaches which combine CSP and traditional BiVP-CRT and may hold promise for patients with IP or mixed-level block. As various approaches to CRT continue to be studied, physiologic phenotyping of the LBBB pattern remains an important consideration.

Clinical predictors of pulmonary embolism for inpatients: are computed tomography pulmonary angiograms being requested appropriately?

The heterogeneity of inpatient pulmonary embolism (PE) presentations may lead to computed tomography pulmonary angiograms (CTPA) being over-requested. Current clinical predictors for PE, including Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC), have predominantly focussed on outpatient and emergency department populations. To determine the clinical indicators for ordering inpatient CTPA and the predictors of positive scans for PE. Consecutive inpatient CTPA (performed >24 h after admission) from January 2017 to December 2017 were retrospectively reviewed. Variables including baseline characteristics, vital signs and risk factors for PE were extracted. A total of 312 CTPA was reviewed (average patient age 67 years; 46% male) and 36 CTPA were positive for PE (11.5%). The average time to inpatient CTPA request was 7 days. Clinical indicators associated with positive scans were hypoxia (odds ratio (OR) 2.4; 95% confidence interval (CI) 1.1-5.6), tachypnoea (OR 2.5; 95% CI 1.2-6.0), recent surgery or immobilisation (OR 2.7; 95% CI 1.2-6.4), S1Q3T3 pattern on electrocardiogram (ECG; OR 7.2; 95% CI 1.4-35.7) and right bundle branch block pattern on ECG (OR 4.7; 95% CI 1.6-13.1). Hypotension, fever and malignancy were not significant. Both PERC and Wells criteria had poor positive predictive value (12% and 27% respectively), but the negative predictive value for PERC and Wells was 100% and 95.8% respectively. Inpatient CTPA appear to be over-requested and can potentially be rationalised based on a combination of clinical predictors and Wells criteria and/or PERC rule. Further prospective studies are needed to develop accurate clinical decision tools targeted towards inpatients.

Predictive Value of Left Atrial Remodeling for Response to Cardiac Resynchronization Therapy.

Response to cardiac resynchronization therapy varies significantly among patients, with one third of them failing to demonstrate left ventricular reverse remodeling after cardiac resynchronization therapy. Left atrial size and function is increasingly recognized as a marker of disease severity in the heart failure population. The aim of this study was to evaluate whether echocardiographic left atrial indices predict left ventricular reverse remodeling after cardiac resynchronization therapy. Ninety-nine cardiac resynchronization therapy candidates were prospectively included in the study and underwent echocardiography before and 3-months after cardiac resynchronization therapy implantation. Cardiac resynchronization therapy response was defined as a 15% relative reduction in left ventricular end-systolic volume. Indexed left atrial volume, left atrial reservoir strain, left ventricular end-diastolic volume, and left ventricular ejection fraction along with other known predictors of cardiac resynchronization therapy response (gender, etiology of heart failure, presence of typical left bundle branch block pattern, QRS duration >150 ms) were included in a multivariate logistic regression model to identify predictors for cardiac resynchronization therapy response. Cardiac resynchronization therapy response occurred in n = 63 (64%) patients. The presence of a typical left bundle branch block (OR 4.2, 95 CI: 1.4-12.1, p = 0.009), QRS duration >150 ms (OR 4.2, 95 CI: 1.4-11.0, p = 0.029), and left atrial volume index (OR: 0.6, 95 CI: 0.4-0.9, p = 0.012) remained the only significant predictors for cardiac resynchronization therapy response after three months. None of the baseline left ventricular parameters showed an independent predictive value. Left atrial size at baseline is an independent predictor and is inversely proportional to left ventricular volumetric reverse remodeling in cardiac resynchronization therapy candidates.

Type A Wellens’ syndrome - A critical electrocardiographic sign

Wellens’ syndrome was first described in 1982[1] and classified into type A and type B. Type A Wellens’ syndrome is characterized by biphasic T-waves in leads V2 and V3, and type B is characterized by deep symmetrical T-wave inversions in the same leads. The study reported that Wellens’ syndrome electrocardiographic (ECG) finding related to left anterior descending (LAD) total or near-total occlusion, which is also described as one of the ST-segment elevation myocardial infarction (STEMI) equivalent signs.[2] Cardiology consultation for possible coronary angiography is necessary for evaluating patients.[3] A 29-year-old male without underlying medical diseases was admitted to our emergency department due to intermittent retrosternal chest tightness for 1 week. His chest pain usually occurs after exertion, accompanied by nausea and dizziness, and subsides 10–15 min after rest. He did not notice other exacerbating or relieving factors. Thus, he visited our emergency department for a consultation. The patient is a nonsmoker with no family history of acute coronary syndrome. In the emergency department, his chest pain had already subsided. He was vitally stable. On physical examination, his cardiac auscultation revealed a regular heartbeat with no murmurs. His ECG performed in the emergency department showed sinus rhythm with biphasic T-waves in leads V2 and V3 without precordial Q waves [Figure 1], which is compatible with type A Wellens’ syndrome. As for his blood examination, his troponin I level is 3.2 ng/mL (normal range < 0.02 ng/mL) and creatine kinase-myocardial band mass is 8.5 ng/mL (normal range <5 ng/mL). He also had thrombocytosis with a platelet count of 993,000/μL.Figure 1: Patient’s initial ECG. ECG: ElectrocardiographicThe patient received aspirin, ticagrelor, and heparin for the myocardial infarction. He received urgent coronary angiography and the examination showed an 85% stenosis of the proximal LAD artery [Figure 2] that was successfully opened through angioplasty. Two drug-eluted stents were placed. After angioplasty, his ECG showed sinus rhythm with no Wellens’ pattern. In addition, he did not experience any chest pain attack after angioplasty. On admission, the patient was diagnosed with essential thrombocythemia through positive JAK-2 V617F mutation test and bone marrow biopsy.Figure 2: Patient’s coronary angiography showed LAD stenosis. (Left) Before the intervention. (Right) After the intervention. LAD: Left anterior descendingWellens’ syndrome is one of the STEMI equivalent ECG signs that need to be treated as acute myocardial infraction in the emergency department.[2] A previous study[1] showed that 75% of the patients with Wellens’ syndrome developed extensive anterior wall myocardial infarction a few weeks after admission. T-wave findings of Wellens’ syndrome are classified into two patterns. In type B, which comprises approximately 75% of cases, the T-wave is deeply inverted and the inverted T-wave is symmetric in contour. In type A, which comprises 25% of cases, the T-wave is biphasic in leads V2 and V3. Other ECG criteria included no loss of R rave or precordial Q waves. Considering noncoronary causes of T-wave inversions, the left ventricular hypertrophy and bundle branch block patterns should be readily recognized by their significant coexistent findings.[3] The characteristic ECG pattern often develops when the patient is not experiencing angina.[3] Patients with ET may present with vasomotor symptoms such as myocardial infarction or stroke. However, in this case, the patient was young and without any risk factors for myocardial infarction before diagnosis. Prompt recognition of the ECG pattern and early cardiology consultation are essential to prevent missing the diagnosis of myocardial infarction. Declaration of patient consent The authors certify that they have obtained appropriate patient consent form. In the form, the patient has given his consent for the images and other clinical information to be reported in the journal. The patient understands that name and initial will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Premature Complexes and Blocked P Wave.

Premature Complexes and Blocked P Wave.

Left bundle branch pacing preserves ventricular mechanical synchrony better than right ventricular pacing-a two-center study

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch pacing (LBBP) has emerged as a novel pacing method. We sought to evaluate left ventricular (LV) mechanical synchrony under permanent LBBP and compare it with conventional and leadless right ventricular pacing (CRVP, LRVP). Methods Sixty-four patients with pacing indication for bradycardia were prospectively enrolled. Twenty-two patients received LBBP in the basal ventricular septum. Twenty-three patients received CRVP and 19 LRVP. All patients underwent echocardiography before and after device implantation. Myocardial work was estimated by pressure-strain analysis. Regional work in the septum (SEP) and lateral wall (LW) was calculated as the average from the respective basal and mid-ventricular segments in the apical four-chamber and three-chamber view. The absolute difference between work in LW and SEP (LW-S-work difference) was used as a measure of asymmetry in workload. Results Baseline characteristics were similar among the three groups. The electrocardiogram during LBBP showed a right bundle branch block pattern; during CRVP and LRVP a left bundle branch block pattern. The paced QRS duration was 114.27±9.9 ms in the LBBP group, significantly shorter than that in the CRVP and LRVP groups (153.9±25.26 ms and 159.1±13.99ms, respectively, both p&amp;lt;0.001). The SEP work decreased in all groups during ventricular pacing (all P&amp;lt;0.05), while the LW work remained similar. The paced LW-S work difference and work difference change between pacing on and off were more significant in the CRVP (1012.9±566.0mmHg*%) and LRVP group (1066.1±472.6mmHg*%) than the LBBP group (260.5±239.8mmHg*%, both P&amp;lt;0.001). In addition, LW-S work difference during ventricular pacing and work difference change between pacing and baseline were comparable in CRVP and LRVP group. Conclusion LBBP causes less LV dyssynchrony than CRVP and LRVP as it preserves a more physiologic conduction pattern. CRVP and LRVP did not differ in this respect. Further studies need to prove that LBBP has advantages over RVP with regards to preservation of LV synchrony and contractility.

Electrocardiographic analysis of left bundle branch area pacing induced right ventricular activation delay

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) aims to capture the area of left bundle branch, resulting in fast activation of the left ventricle (LV) but delayed right ventricular (RV) activation. During intrinsic cardiac conduction, delayed RV activation results on the electrocardiogram (ECG) in a right bundle branch block (RBBB) pattern and is generally considered benign. As such, LBBAP-induced delayed RV activation is thought not to be harmful. However, to what extent left and right ventricular activation times during LBBAP resembles that of healthy individuals with acquired RBBB is currently not known. Methods Individuals with incomplete RBBB (iRBBB), complete RBBB (cRBBB) and LBBAP were included. Standard twelve lead electrocardiograms (ECG) were stored and analysed digitally using the MUSE ECG database. QRS duration was measured as global QRS duration. Left and right ventricular activation times were estimated by R-wave peak time in lead V6 (V6RWPT) and R’ peak time in lead V1 (V1RWPT), respectively. Delayed RV activation was further characterized by duration and area of R’ wave in lead V1. Results Paced QRS duration during LBBAP (n=86) measured 129±15ms whereas QRS duration of iRBBB (n=422) and cRBBB (n=223) individuals measured 103±8ms and 142±17ms respectively (p&amp;lt;0.001). V6RWPT during LBBAP (47±15ms) was significantly longer than V6RWPT in iRBBB (40±5ms) and cRBBB (39±7ms) (p&amp;lt;0.001). With LBBAP, V1RWPT (83±15ms) became delayed compared to iRBBB (74±9ms, p&amp;lt; 0.001), but remained shorter in comparison to cRBBB (98±17ms, p&amp;lt;0.001). Patients with LBBAP were further characterized by V1 R’ duration and R’ area which were shorter and smaller compared to cRBBB but similar to iRBBB individuals. Conclusion LBBAP-induced delayed RV activation resembles electrocardiographically more closely to the delayed RV activation as seen in individuals with incomplete rather than complete RBBB. Left ventricular activation times remain slightly prolonged during LBBAP as compared to RBBB individuals.

Long-term study on electrophysiological characteristics and catheter ablation of idiopathic ventricular arrhythmias originating from the left ventricular posterior papillary muscles guided by intracardiac ultrasound.

BackgroundThis study aimed to investigate the electrophysiological characteristics of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular posterior papillary muscles (LPPM) and explore the efficiency of catheter ablation using three‐dimensional intracardiac ultrasound technology.MethodsTwenty‐seven cases of premature ventricular contraction/ventricular tachycardia (PVC/VT) originating from the left ventricular posterior papillary muscles were recorded from July 2015 to June 2019 in the Central Hospital of Shengli Oil Field and the First Affiliated Hospital of Zhengzhou University. Electrophysiological mapping and radiofrequency catheter ablation (RFCA) were performed using three‐dimensional intracardiac ultrasound technology. The characteristics of the body surface and intracavity electrocardiogram were analyzed. All cases were followed up for 24 months after the operation.ResultsThe VAs of all 27 cases were successfully eliminated by catheter ablation. QRS complexes were observed with a right bundle branch block (RBBB) pattern and a steep slope in the initial segment. Lead I appeared with an Rs pattern, and inferior leads (lead II, III, and aVF) were usually with an S wave. The lead aVR appeared with a qR pattern, while the R wave was commonly found in aVL. The main wave in leads V1‐V3 was positive but negative in V5 and V6.ConclusionVentricular arrhythmias originating from the left ventricular posterior papillary muscles have similar electrophysiological characteristics. The origin site was accurately located using three‐dimensional intracardiac ultrasound technology. Catheter ablation effectively eliminated VAs.