New-onset Right Bundle Branch Block Research Articles

Impact of New-Onset Right Bundle-Branch Block After Transcatheter Aortic Valve Replacement on Permanent Pacemaker Implantation.

A delayed and recurrent complete atrioventricular block (CAVB) is a life-threatening complication of transcatheter aortic valve replacement (TAVR). Post-TAVR evaluation may be important in predicting delayed and recurrent CAVB requiring permanent pacemaker implantation (PPI). The impact of new-onset right bundle-branch block (RBBB) after TAVR on PPI remains unknown. In total, 407 patients with aortic stenosis who underwent TAVR were included in this analysis. Intraprocedural CAVB was defined as CAVB that occurred during TAVR. A 12-lead ECG was evaluated at baseline, immediately after TAVR, on postoperative days 1 and 5, and according to the need to identify new-onset bundle-branch block (BBB) and CAVB after TAVR. Forty patients (9.8%) required PPI, 17 patients (4.2%) had persistent intraprocedural CAVB, and 23 (5.7%) had delayed or recurrent CAVB after TAVR. The rates of no new-onset BBB, new-onset left BBB, and new-onset RBBB were 65.1%, 26.8%, and 4.7%, respectively. Compared with patients without new-onset BBB and those with new-onset left BBB, the rate of PPI was higher in patients with new-onset RBBB (3.4% versus 5.6% versus 44.4%, P<0.0001). On post-TAVR evaluation in patients without persistent intraprocedural CAVB, the multivariate logistic regression analysis showed that new-onset RBBB was a statistically significant predictor of PPI compared with no new-onset BBB (odds ratio [OR], 18.0 [95% CI, 5.94-54.4]) in addition to the use of a self-expanding valve (OR, 2.97 [95% CI, 1.09-8.10]). Patients with new-onset RBBB after TAVR are at high risk for PPI.

Incidence and Outcomes of New-Onset Right Bundle Branch Block Following Transcatheter Aortic Valve Replacement.

The incidence and prognosis of right bundle branch block (RBBB) following transcatheter aortic valve replacement (TAVR) are unknown. Hence, we sought to characterize the incidence of post-TAVR RBBB and determine associated risks of permanent pacemaker (PPM) implantation and mortality. All patients 18 years and above without preexisting RBBB or PPM who underwent TAVR at US Mayo Clinic sites and Mayo Clinic Health Systems from June 2010 to May 2021 were evaluated. Post-TAVR RBBB was defined as new-onset RBBB in the postimplantation period. The risks of PPM implantation (within 90 days) and mortality following TAVR were compared for patients with and without post-TAVR RBBB using Kaplan-Meier analysis and Cox proportional hazards modeling. The risks of PPM implantation (within 90 days) and mortality following TAVR were compared for patients with and without post-TAVR RBBB using Kaplan-Meier analysis and Cox proportional hazards modeling. Of 1992 patients, 15 (0.75%) experienced new RBBB post-TAVR. There was a higher degree of valve oversizing among patients with new RBBB post-TAVR versus those without (17.9% versus 10.0%; P=0.034). Ten patients (66.7%) with post-TAVR RBBB experienced high-grade atrioventricular block and underwent PPM implantation (median 1 day; Q1, 0.2 and Q3, 4), compared with 268/1977 (13.6%) without RBBB. Following propensity score adjustment for covariates (age, sex, balloon-expandable valve, annulus diameter, and valve oversizing), post-TAVR RBBB was significantly associated with PPM implantation (hazard ratio, 8.36 [95% CI, 4.19-16.7]; P<0.001). No statistically significant increase in mortality was seen with post-TAVR RBBB (hazard ratio, 0.83 [95% CI, 0.33-2.11]; P=0.69), adjusting for age and sex. Although infrequent, post-TAVR RBBB was associated with elevated PPM implantation risk. The mechanisms for its development and its clinical prognosis require further study.

The ratio of QRS/RV6-V1: a new electrocardiographic predictor of short- and long-term adverse clinical outcomes in patients with acute myocardial infarction combined with new-onset right bundle branch block.

A few studies have focused on electrocardiography (ECG) parameters correlating with clinical prognosis in patients with acute myocardial infarction (AMI) combined with new-onset right bundle branch block (RBBB). To assess the prognostic value of a new ECG parameter, namely, the ratio of QRS duration/RV6-V1 interval (QRS/RV6-V1), in patients with AMI combined with new-onset RBBB. A total of 272 AMI patients combined with new-onset RBBB who received primary percutaneous coronary intervention (P-PCI) were retrospectively enrolled in the study. First, the patients were divided into survival group and non-survival group. Demographic, angiographic, and ECG characteristics were compared between the two groups. Receiver operating characteristic (ROC) curve was used to screen the best ECG parameter for predicting 1-year mortality. Second, the ratio of QRS/RV6-V1, a continuous variable, was converted to the high ratio group and low ratio group according to the optimal cutoff value point determined by the X-tile software. We compared the patient's demographic, angiographic, and ECG characteristics, in-hospital major adverse cardiovascular events (MACE), and 1-year mortality between the two groups. Multivariate logistic and Cox regressions were used to evaluate whether the ratio of QRS/RV6-V1 was an independent prognostic factor of in-hospital MACE and 1-year mortality. The ROC curve showed that the ratio of QRS/RV6-V1 had a higher value for predicting in-hospital MACE and 1-year mortality than the QRS duration, RV6-V1 interval, and RV1 interval. The patients in the high ratio group had significantly higher CK-MB peak and Killip class, lower ejection fraction (EF%), higher ratio of the left anterior (LAD) descending artery as infarct-related artery (IRA), and longer total ischemia time (TIT) than those in the low ratio group. The QRS duration was wider in the high ratio group than that in the low ratio group, whereas RV6-V1 was narrower in the high ratio group compared with that in the low ratio group. The in-hospital MACE rate (93.3% vs. 31.0%, p < 0.001) and 1-year mortality rate (86.7% vs. 13.2%, p < 0.001) in the high ratio group were higher than those in the low ratio group. The higher ratio of QRS/RV6-V1 was an independent predictor of in-hospital MACE (odds ratio, 8.55; 95% CI, 1.40-52.37; p = 0.02) after adjusting other confounders. Cox regression showed that the higher ratio of QRS/RV6-V1 predicted higher 1-year mortality of the patients with AMI combined with new-onset RBBB [hazard ratios (HR), 12.4; 95% CI, 7.26-21.22); p < 0.001] than the lower ratio of QRS/RV6-V1, and the HR still stayed at 2.21 even after a multivariable adjustment (HR, 2.21; 95% CI, 1.05-4.64); p = 0.037). According to the results of our study, the high ratio of QRS/RV6-V1 (>3.0) was a valuable predictor of short- and long-term adverse clinical outcomes in AMI patients combined with new-onset RBBB. The implications of the high ratio of QRS/RV6-V1 were severe ischemia and pseudo synchronization between bi-ventricle.

Association between new-onset right bundle branch block and primary or secondary ventricular fibrillation in ST-segment elevation myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Background New-onset right bundle branch block (RBBB) in myocardial infarction (MI) is often associated with ventricular fibrillation (VF) but the nature of this relationship has not been determined. Aims To investigate the association between new-onset RBBB and VF in ST-segment elevation MI (STEMI) as well as its peculiarities attending to the permanent or transient character of RBBB and the distinction of VF as primary or secondary. Methods and results Between 1998 and 2014, among other data, incidence and duration of RBBB and VF occurrence were prospectively collected in 5301 patients with ST-segment elevation MI (STEMI) admitted to two Coronary Care Units. Multinomial adjusted logistic regression analyses were used to examine the association between RBBB, attending to its duration, and VF according to its primary VF (PVF) (&amp;lt;24h from symptom-onset and Killip I) or secondary VF (SVF) (&amp;gt;24h from symptom-onset and/or Killip&amp;gt;I) character. Among 284 (5.4%) patients with new-onset RBBB, 158 were transient and 126 permanent. VF occurred in 339 (6.4%) patients, 201 PVF and 138 SVF, documented within the first 2 h of symptoms-onset in 78% and 60%, respectively. Newonset RBBB was more frequent in PVF (11.4%) and SVF (20.3%), than in non-VF (4.7%). Transient RBBB incidence was higher in PVF (9.0%) and SVF (9.4) than in non-VF (2.6%), whereas permanent RBBB was higher in SVF (10.9%) than PVF (2.5%) and non-VF (2.1%). New-onset RBBB 1.83 [95% confidence interval (CI): 1.07–3.11] and new-onset transient RBBB 2.39 (95% CI: 1.32–4.32) were independently associated with PVF. New-onset 3.03 (95% CI: 1.83–5.02), transient 2.40 (95% CI: 1.27–4.55), and permanent 2.99 (95% CI: 1.52–5.86) RBBB were independently associated with SVF. Conclusion New-onset RBBB and VF in STEMI are independently associated and show particularities based on the duration of the conduction disturbance and/or the primary or secondary character of the arrhythmia.

PO-05-019 WHEN RIGHT IS WRONG: INCIDENCE AND OUTCOMES OF RIGHT BUNDLE BRANCH BLOCK FOLLOWING TRANSCATHETER AORTIC VALVE REPLACEMENT

Right bundle branch block (RBBB) following transcatheter aortic valve replacement (TAVR) for aortic stenosis is uncommon. However, its incidence and prognosis have not been well-described. To characterize the incidence of post-TAVR RBBB alongside its associated risk of permanent pacemaker (PPM) implantation and mortality. All patients ≥18 years who underwent TAVR at the Mayo Clinic Enterprise from June 2010 to May 2021 were considered; patients with pre-TAVR RBBB and/or PPM were excluded from the analysis. Clinical history, imaging variables, and electrocardiographic data were abstracted from the electronic medical records. Post-TAVR RBBB, defined as new onset RBBB in the postprocedure period, was manually verified by the study authors. The risks of PPM implantation (within 90-days post-TAVR) and mortality following TAVR were compared between patients with and without post-TAVR RBBB using the Kaplan-Meier method and Cox proportional hazards modeling. Out of 1992 patients included, 15 (0.75%) experienced new RBBB post-TAVR. There was a higher proportion of patients who had valve oversizing among patients with new RBBB post-TAVR versus not (17.9% versus 10.0%, p=0.034). There were no other significant differences in demographics or clinical characteristics between patients with and without post-TAVR RBBB including age at TAVR, sex, type of valve implanted, valve size, aortic valve calcium score, or left ventricular ejection fraction (Table 1). Ten patients (66.7%) with post-TAVR RBBB experienced high-grade atrioventricular block (≥2 consecutive blocked P waves) and subsequently underwent PPM implantation (median 4 days; interquartile range 1-90 days), compared to 268/1977 (13.6%) without RBBB (Figure 1). After adjustment for age, sex, balloon expandable valve, annulus diameter, and valve oversizing, post-TAVR RBBB was significantly associated with PPM implantation (hazard ratio [HR] 8.36, 95% confidence interval [CI] 4.19-16.7; p<0.001). No statistically significant increase in mortality was seen with post-TAVR RBBB (HR 0.83, 95% CI 0.33-2.11; p=0.69) following adjustment for age and sex. Although encountered rarely, post-TAVR RBBB was associated with an elevated risk of PPM implantation. The mechanisms for its development and its clinical prognosis require further study.Tabled 1Table 1: Baseline characteristics of study cohortMedian (IQR) or No. (%) of patientsVariableNNo RBBB (N=1977)New-Onset RBBB (N=15)P-valueAge at TAVR1,99281.3 (75.4, 86.0)82.6 (78.8, 87.4)0.45Sex (Males)1,9921,111 (56.2%)9 (60.0%)0.80Balloon Expandable Valve1,9921,744 (88.2%)12 (80.0%)0.41Valve size1,99226.0 (23.0, 29.0)26.0 (24.5, 29.0)0.49Annulus Area (cmˆ2) based on CT1,8504.7 (4.0, 5.4)4.6 (4.3, 5.1)0.81Annulus Diameter (mm)1,93027.0 (25.0, 29.1)26.0 (25.1, 28.8)0.87Valve Oversizing *1,85010.0 (3.0, 18.5)17.9 (15.4, 23.4)0.034LVEF (%)1,89762.0 (55.0, 66.0)61.5 (54.2, 67.8)0.97AV Peak Velocity1,8974.2 (4.0, 4.6)4.1 (4.0, 4.3)0.42AV Mean Gradient1,89743.0 (38.0, 51.0)41.5 (41.0, 44.8)0.76AV Area1,8970.8 (0.7, 0.9)0.9 (0.8, 1.0)0.33LVOT AV Velocity Ratio1,8970.2 (0.2, 0.2)0.2 (0.2, 0.3)0.47LVOT AV TVI Ratio1,8970.2 (0.2, 0.2)0.2 (0.2, 0.3)0.51LVOT Dimension1,7292.2 (2.1, 2.3)2.2 (2.1, 2.3)0.77LV Geometry9710.64Concentric Hypertrophy359 (37.4%)5 (45.5%)Concentric Remodeling264 (27.5%)2 (18.2%)Eccentric Hypertrophy158 (16.5%)3 (27.3%)Normal Geometry179 (18.6%)1 (9.1%)LVED Dimension1,55649.0 (45.0, 53.0)48.0 (43.0, 53.5)0.64Aortic Valve Calcium Score1,7302,281.0 (1,556.5, 3,169.5)2,729.0 (1,979.1, 3,480.5)0.31Myocardial Infarct1,987137 (6.9%)2 (13.3%)0.28Congestive Heart Failure1,987522 (26.5%)5 (33.3%)0.56Charlson Comorbidity Index1,9872.0 (0.0, 4.0)2.0 (1.0, 4.0)0.61STS Risk Score1,7304.8 (3.0, 8.0)4.0 (3.1, 9.2)0.86P-values result from a Wilcoxon rank sum test (continuous variables) or Fisher’s exact test (categorical variables). *Valve oversizing = (Nominal Area / Annulus area (mm)) -1) *100 AV – aortic valve; CT – computed tomography; IQR – interquartile range; LVEF – left ventricular ejection fraction; LVOT – left ventricular outflow tract; STS – Society of Thoracic Surgeons; TAVR – transcatheter aortic valve replacement; TVI - tissue velocity index Open table in a new tab

Inferior ST-Segment Elevation Can Predict In-Hospital Mortality in Patients with Anterior Myocardial Infarction Complicated by Ventricular Septal Rupture.

Background Electrocardiogram (ECG) findings in patients with anterior wall myocardial infarction (MI) complicated by ventricular septal rupture (VSR) have rarely been studied. Methods We conducted a single-center retrospective study among patients with anterior MI complicated by VSR over the past ten years. The presence of ST-segment elevation (STE) in inferior leads and new onset of complete right bundle branch block (RBBB) on ECG were studied for the prediction of in-hospital mortality. Results Among the 85 patients enrolled, 45 (52.9%) were male, with a median age of 70 years. Sixty-five patients (76.5%) died in the hospital, and the remaining 20 patients (23.5%) had improved conditions and were discharged. Inferior STE was present in 35 patients (41.2%), including 32 patients in the death group and 3 patients in the survival group (P = 0.005). New-onset RBBB was present in 25 patients (29.4%), with 22 patients in the death group and 3 patients in the survival group (P = 0.103). Multivariate logistic regression showed that inferior STE was an independent predictor of in-hospital death in patients with anterior MI and VSR (OR: 14.488; 95% CI: 1.708-122.887; P = 0.014). Conclusions In patients with anterior MI complicated by VSR, inferior STE was associated with a higher risk of in-hospital mortality.

Poor Outcome of Right Bundle Branch Block Coexist with ST-Elevation Myocardial Infarction

BACKGROUND: The incidence of new-onset right bundle branch block (RBBB) coexistence with ST-elevation myocardial infarction (STEMI) has been associated with higher in-hospital mortality compared with those without RBBB. CASES: We present three cases of new-onset RBBB coexist with STEMI. Case I: a 64 years old male presented Killip I STEMI inferior-anterior with RBBB as new-onset. Rescue percutaneous coronary intervention (PCI) after failed thrombolytic was performed. New-onset atrial fibrillation (AF) with rapid ventricular response worsened his hemodynamic profile, leading to cardiogenic shock. Case II: an 80 years old male presented Killip IV late-onset anterior STEMI with new-onset RBBB. Cardiogenic shock got worsened after PCI stent. Case III: a 65 years old male presented Killip II extensive anterior STEMI with new-onset RBBB who underwent a primary PCI stent. Recurrent ventricular tachycardia (VT), worsening cardiogenic shock, and transient AV block occurred after PCI. The right bundle branch blood supply is mainly provided by a septal branch of left descending artery (LAD). Therefore, it may indicate proximal LAD occlusion and extensive infarction. Thus, catastrophic events may occur, which including acute heart failure, AV block, malignant ventricular arrhythmia, new-onset AF, and mostly cardiogenic shock, despite initiate reperfusion was performed without delay once the diagnosis is confirmed. CONCLUSION: New RBBB suggests poor short-term prognosis due to its complication. Higher mortality is mostly linked to worsening cardiogenic shock.

Clinical characteristics and the severity of coronary atherosclerosis of different subtypes of bundle-branch block.

BackgroundRight bundle‐branch block (RBBB) and left bundle‐branch block (LBBB) play a role in the pathogenesis and progression of coronary artery disease (CAD). However, the clinical features and the severity of coronary artery disease associated with different subtypes of bundle‐branch block, according to time of new appearance, is not well characterized in patients with no known CAD.MethodsWe retrospectively analyzed data pertaining to consecutive patients with RBBB or LBBB who underwent coronary angiography. The severity of coronary lesions was evaluated using the SYNTAX score. The differential effect of new‐onset RBBB, old RBBB, new‐onset LBBB, and old LBBB on the severity of CAD and its association with clinical characteristics was quantified. Multivariate logistic regression analysis was performed to evaluate the effect of RBBB and LBBB on the degree of coronary atherosclerosis in patients without known CAD.ResultsOut of the 243 patients, 72 patients had old LBBB, 37 had new‐onset LBBB, 93 patients had old RBBB, and 41 patients had new‐onset RBBB. On univariate analysis, age, systolic blood pressure, diastolic blood pressure, creatinine, serum glucose, and glycosylated hemoglobin level were associated with high SYNTAX score (p < .05 for all). Patients in the new‐onset RBBB, old RBBB, new‐onset LBBB, and old LBBB groups showed significant differences in baseline characteristics and coronary atherosclerosis (p < .05 for all). However, there were no significant between‐group differences with respect to the degree of coronary atherosclerosis as assessed by SYNTAX score.ConclusionsNew‐onset RBBB, old RBBB, new‐onset LBBB, and old LBBB were not associated with the severity of coronary lesions as assessed by SYNTAX score in patients without known CAD.

Association between new-onset right bundle branch block and primary or secondary ventricular fibrillation in ST-segment elevation myocardial infarction.

New-onset right bundle branch block (RBBB) in myocardial infarction (MI) is often associated with ventricular fibrillation (VF) but the nature of this relationship has not been determined. Between 1998 and 2014, among other data, incidence and duration of RBBB and VF occurrence were prospectively collected in 5301 patients with ST-segment elevation MI (STEMI) admitted to two University Hospitals in Murcia (Spain). Multinomial adjusted logistic regression analyses were used to examine the association between RBBB, attending to its duration, and VF according to its primary VF (PVF) or secondary VF (SVF) character. Among 284 (5.4%) patients with new-onset RBBB, 158 were transient and 126 permanent. VF occurred in 339 (6.4%) patients, 201 PVF and 138 SVF, documented within the first 2 h of symptoms-onset in 78% and 60%, respectively. New-onset RBBB was more frequent in PVF (11.4%) and SVF (20.3%), than in non-VF (4.7%). Transient RBBB incidence was higher in PVF (9.0%) and SVF (9.4) than in non-VF (2.6%), whereas permanent RBBB was higher in SVF (10.9%) than PVF (2.5%) and non-VF (2.1%). New-onset RBBB 1.83 [95% confidence interval (CI): 1.07-3.11] and new-onset transient RBBB 2.39 (95% CI: 1.32-4.32) were independently associated with PVF. New-onset 3.03 (95% CI: 1.83-5.02), transient 2.40 (95% CI: 1.27-4.55), and permanent 2.99 (95% CI: 1.52-5.86) RBBB were independently associated with SVF. New-onset RBBB and VF in STEMI are independently associated and show particularities based on the duration of the conduction disturbance and/or the primary or secondary character of the arrhythmia.

Takotsubo cardiomyopathy and new-onset right bundle branch block in uncomplicated right ventricle pacing: Cause or coincidence?

Normally in the right ventricular (RV) paced rhythm, the electrocardiogram pattern will be of left bundle branch block (LBBB) pattern. A small percentage of patients can have right bundle branch block (RBBB) pattern in uncomplicated RV pacing. We are reporting here a rare occurrence of a new-onset RBBB in an RV paced patient which was coinciding with the onset of takotsubo cardiomyopathy following pulse generator re-implantation procedure.

Clinical Impact of Preexisting Right Bundle Branch Block after Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis.

Introduction Transcatheter aortic valve replacement (TAVR) is now the treatment of choice for patients with severe aortic stenosis regardless of their surgical risk. Right bundle branch block (RBBB) can be a predictor for development of significant atrioventricular (AV) block after TAVR, requiring permanent pacemaker implantation (PPI). However, data related to the risk of PPI requirement with preexisting RBBB is scarce. Hence, this systematic review and meta-analysis aims to assess clinical outcomes of patients undergoing TAVR with RBBB on preexisting electrocardiogram. Methods We performed a systematic literature review to identify randomized and nonrandomized clinical studies that reported any clinical impact of patients undergoing TAVR with preexisting RBBB. A total of eight databases including PubMed (Medline), Embase, Cochrane Library, ACP Journal Club, Scopus, DARE, and Ovid containing articles from January 2000 to May 2020 were analyzed. Results We identified and screened 224 potential eligible publications through the databases and found 14 relevant clinical trials for a total of 15,319 participants. There was an increased 30-day pacemaker implantation rate of 38.1% in the RBBB group compared to 11.4% in the no RBBB group with a risk ratio of 3.56 (RR 3.56 (95% CI 3.21–3.93, p < 0.01)). There was an increased 30-day all-cause mortality in the RBBB group of 9.5% compared with 6.3% in the no RBBB group with an odds ratio of 1.60 (OR 1.60 (95% CI 1.14–2.25, p < 0.01)). Conclusion This study indicates that patients with preexisting RBBB have higher incidence of PPI and all-cause mortality after TAVR compared with patients without RBBB. Further trials are needed to compare the clinical outcomes based on TAVR valve types and assess the benefit of PPI in patients with new-onset RBBB after TAVR.

Prognostic value of new-onset right bundle-branch block in acute myocardial infarction patients: a systematic review and meta-analysis.

BackgroundPatients with acute myocardial infarction (AMI) and bundle-branch block have poor prognoses. The new European Society of Cardiology guideline suggests a primary percutaneous coronary intervention strategy when persistent ischemic symptoms occur in patients with persistent ischemic symptoms and right bundle-branch block (RBBB), but the level of evidence is not high. In fact, the presence of RBBB may lead to the misdiagnosis of transmural ischemia and mask the early diagnosis of ST-elevation myocardial infarction. Moreover, new-onset RBBB is occasionally caused by AMI. Our study aims to investigate the prognostic value of new-onset RBBB in AMI.Methods and ResultsWe conducted a meta-analysis of studies to evaluate the prognostic value of RBBB in AMI patients. Of 914 primary records, five studies and 874 MI patients were included for meta-analysis. Compared with previous RBBB, AMI patients with new-onset RBBB had a higher risk of long-term mortality (RR, 1.66, 95% CI [1.31–2.09], I2 = 0.0%, p = 0.000, n = 2), ventricular arrhythmia (RR, 4.86, 95% CI [2.10–11.27], I2 = 0.0%, p = 0.000, n = 3), and cardiogenic shock (RR, 2.76, 95% CI [1.66–4.59], I2 = 0.0%, p = 0.000, n = 3), but a lower risk of heart failure (RR, 0.66, 95% CI [0.52–0.85], I2 = 2.50%, p = 0.001, n = 4). Compared with AMI patients with new-onset permanent RBBB, patients with new-onset transient RBBB had a lower risk of short-term mortality (RR, 0.20, 95% CI [0.11–0.37], I2 = 44.1%, p = 0.000, n = 4).ConclusionNew-onset RBBB is likely to increase long-term mortality, ventricular arrhythmia, and cardiogenic shock, but not heart failure in AMI patients. AMI patients with new-onset transient RBBB have a lower risk of short-term mortality than those with new-onset permanent RBBB. Revascularization therapies should be considered when persistent ischemic symptoms occur in patients with RBBB, especially new-onset RBBB.

Diagnosis, prognostic significance, and characteristics of new-onset right bundle-branch block in patients with acute myocardial infarction: Protocol for a systematic review and meta-analysis

BACKGROUND: Many studies have shown that patients with acute Myocardial Infarction (AMI) and Bundle Branch Block (BBB) may have a worse prognosis than patients with only acute myocardial infarction. Current guidelines recommend reperfusion therapy in patients with ST-segment elevation AMI or left bundle branch block AMI. Curiously, the right bundle-branch block (RBBB) is not listed as an indication for reperfusion therapy. However, some studies did not find a significant prognostic value of RBBB in acute myocardial infarction. Furthermore, distinction between old and new bundle-branch block is seldom made in previously studies. Our study is to investigate the incidence, clinical characteristics, diagnosis, and prognostic significance of new-onset RBBB in acute myocardial infarction. METHODS AND ANALYSIS: A systematic review of studies evaluating the prognosis of right and left bundle-branch block in acute myocardial infarction will be undertaken. PubMed, EMBASE, Ovid, Cochrane Library and Web of Science will be searched electronically. Reference lists of related reviews, included studies and key journals will be manual-searched to identify further studies for inclusion. Two reviewers will independently complete publication type. Title, abstract and full-text will be screened to determine study eligibility according to the Patient-Intervention-Control-Outcomes (PICO) criteria. Data in the final included studies will be extracted. Quality assessment of included studies will be evaluated using the Newcastle-Ottawa Quality Assessment Scale. Stata 22.0 will process the data. ETHICS AND DISSEMINATION: As data in this systematic review and meta-analysis is based on published articles, ethics approval is not required. Dissemination will be undertaken through publication in peer-reviewed journals, and the lead author’s master dissertation. CONCLUSION: Findings may provide with valid and precise risk estimates of new-onset RBBB in AMI for clinicians and other decision-makers.

Utility of Mapping Signals to Improve Precision of Atrioventricular Node Ablation

Atrioventricular node (AVN) ablation is effective for rate control in atrial fibrillation. This may require multiple radiofrequency applications to achieve complete atrioventricular block (CAB). In this retrospective study, we tested the hypothesis that mapping the AVN utilizing electrograms (EGMs) on both proximal and distal bipoles of the mapping catheter may improve the likelihood of CAB. Lesion characteristics and EGM components on the proximal and distal bipoles of the ablation catheter in first-time AVN ablation procedures were analyzed. Outcomes of each lesion, including presence of CAB, acute recurrence of AVN conduction, new-onset right bundle branch block (RBBB), and junctional escape rhythm, were analyzed. Multivariate binary logistic regression analysis was performed to identify EGM characteristics that independently predicted the outcomes of interest. Lesions with these EGM characteristics were then identified and their outcomes compared with the whole cohort. A total of 441 ablation lesions were analyzed. EGM characteristics that independently predicted outcomes were the presence of His and atrial EGMs on the distal bipole and the absence of ventricular EGM on the proximal bipole. Among the 25 lesions with all these characteristics, 18 (72%) resulted in CAB compared to the overall cohort rate of 38% (P = 0.001). There was no new-onset RBBB. The likelihood of acute recurrent AVN conduction and junctional escape rhythm were similar. Combining proximal and distal bipole EGM characteristics of the ablation catheter can improve the accuracy of AVN localization during AVN ablation and avoid right bundle branch injury.

Incidence and prognostic significance of right bundle branch block in patients with acute myocardial infarction receiving thrombolytic therapy

We assessed the incidence and prognostic significance of right bundle branch block (RBBB) in patients with acute myocardial infarction (AMI) receiving thrombolytic therapy. A prospective, one-year follow-up study involving 681 consecutive patients treated with thrombolytic agents for AMI was performed. Seventy-four patients developed RBBB (46% new-onset, 24% old and 30% indeterminate). RBBB was more common in older patients with large anterior AMI. New-onset RBBB were often transient (56%) and 84% of them resolved within 12 h after admission. Complicating events during the hospital phase, such as ventricular arrhythmias and development of heart failure, were more frequent in patients with RBBB. In-hospital and one-year mortality were higher in patients with RBBB (22.9 and 40.5% compared to 7.9 and 12.3% respectively in patients without block, both p<0.001). New-onset, non-transient RBBB were associated with the highest mortality rates (73% at one-year follow-up). By multivariate analysis, RBBB was retained as independent predictor of in-hospital and one-year mortality. We conclude that new-onset RBBB in patients receiving thrombolytic therapy for AMI is often transient. The development of RBBB has a negative and independent prognostic impact on the survival during the hospital phase and at one-year follow-up.