Transient Right Bundle Branch Block Research Articles

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) (<24h from symptom-onset and Killip I) or secondary VF (SVF) (>24h from symptom-onset and/or Killip>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.

Estimation of the QTc interval in the presence of right bundle branch block: A comparative study using validated formulae for left bundle branch block

BackgroundAdequate measurement of the QT interval is of clinical importance in order to identify patients at higher risk for ventricular arrhythmias. Previous studies have described different methods to estimate baseline QT in patients with left bundle branch block (LBBB). However, the evidence regarding the assessment of the QT in patients with right bundle branch block (RBBB) is scarce. AimTo analyze the feasibility and reliability of the different formulae described for LBBB in the estimation of the baseline QT in the presence of RBBB. MethodsWe performed an observational study including patients who underwent electrophysiology study and/or ablation. Two types of RBBB were considered: 1) pacing-induced and 2) transient true RBBB. QRS, JT and QT intervals were measured during baseline and RBBB. Estimated QTc was calculated using LBBB formulae: Bogossian, Rautaharju, Tabatabaei, Tang-Rabkin, Yankelson, Wang. Linear correlation and intraclass correlation coefficients (ICC) were used to assess the reliability of these formulae for the estimation of baseline QTc. ResultsWe finally included a total of 100 patients. Correlations between baseline and estimated QTc were strong (R > 0.7) for all the formulae except for Tabatabaei. Yankelson and Wang showed the highest reliability (ICC = 0.775 and 0.727, respectively). Yankelson appeared to be the most accurate formula, with a mean estimated QTc closest to baseline values. ConclusionPreviously described formulae for LBBB exhibited marked differences regarding reliability in the estimation of the QTc interval in the presence of RBBB. According to our results, Yankelson showed the most consistent and accurate agreement in this setting.

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.

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.

Complete atrioventricular block during tunneled cuffed hemodialysis catheter insertion in a patient with pre-existing left bundle branch block

Arrhythmias are complications of tunneled cuffed hemodialysis catheter insertion. Most complications associated with arrhythmias occur during guide-wire access, where the guide wire can cause traumatic damage to the conduction system of the heart. Conducting system injury in tunneled cuffed hemodialysis catheter insertion often involves the right bundle, causing right bundle branch block (RBBB). Transient RBBB with sinus rhythm is not usually accompanied by abnormal vital signs. However if patients already have left bundle branch block (LBBB), new onset RBBB can cause complete atrioventricular block (AVB), which can lead to fatal complications requiring invasive treatment. We report on a patient with LBBB who developed complete AVB during hemodialysis catheter insertion.

Electrocardiographic features and prevalence of bilateral bundle-branch delay.

Definitive diagnosis of bilateral bundle-branch delay/block may be made when catheter-induced right bundle-branch block (RBBB) develops in patients with baseline left bundle-branch (LBB) block. We hypothesized that a RBBB pattern with absent S waves in leads I and aVL will identify bilateral bundle-branch delay/block. Fifty patients developing transient RBBB pattern in lead V1 during right heart catheterization were studied. Patients were grouped according to whether the baseline ECG demonstrated a normal QRS, left fascicular blocks, or LBB block pattern. The RBBB morphologies in each group were compared. The prevalence of bilateral bundle-branch delay/block pattern was examined in our hospital ECG database. All patients with baseline normal QRS complexes (n=30) or left fascicular blocks (4 anterior, 5 posterior) developed a typical RBBB pattern. Among the 11 patients with a baseline LBB block pattern, 7 developed an atypical RBBB pattern with absent S waves in leads I and aVL and the remaining 4 demonstrated a typical RBBB. The absence of S waves in leads I and aVL during RBBB was 100% specific and 64% sensitive for the presence of pre-existing LBB block. Among the consecutive 2253 hospitalized patients with RBBB, 34 (1.5%) had the bilateral bundle-branch delay/block pattern. An ECG pattern of RBBB in lead V1 with absent S wave in leads I and aVL indicates concomitant LBB delay. Pure RBBB and bifascicular blocks are associated with S waves in leads I and aVL.

Complete right bundle branch block of unique behavior: What is the mechanism?

A 59-year-old hypertensive man presented to the emergency department with an episode of dizziness without syncope. A surface 12-lead electrocardiogram (ECG) showed sinus rhythm at 82 bpm with a 2:1 complete right bundle branch block (RBBB) pattern (Fig. 1). The patient presented a full spontaneous recovery and was subsequently discharged and referred for ambulatory diagnostic work-up. Echocardiography presented moderate septal hypertrophy and no other structural abnormalities. Continuous 24-h 3-lead Holter monitoring was performed which revealed sinus rhythm with narrow QRS complexes at 42 bpm (Fig. 2A), 2:1 RBBB at 60 bpm (Fig. 2B) and 1:1 RBBB at 38 bpm (Fig. 2C). Following this, an exercise stress test was carried out during which a 3:2 RBBB pattern was observed at the maximum heart rate of 116 bpm (Fig. 3). What is the mechanism explaining the different patterns of transient RBBB observed and how can one relate this to the underlying sinus rate?

Effect of Right Bundle Branch Block on Electrocardiographic Amplitudes, Including Combined Voltage Criteria Used for the Detection of Left Ventricular Hypertrophy

Although right bundle branch block (RBBB) delays right ventricular depolarization, its effect on cancellation of right and left ventricular forces within the QRS complex has not been quantified during stable temporal and physiological conditions. Systematic changes in QRS amplitude during transient RBBB bear directly on performance of standard ECG criteria for left ventricular hypertrophy (LVH), and these changes require quantification. We examined the instantaneous effect of RBBB on QRS amplitudes and LVH voltages in 40 patients who had intermittent complete RBBB during a single 10 sec standard 12-lead ECG recording, comprising 0.1% of approximately 400,000 consecutive ECGs in a university teaching hospital setting. Amplitudes were measured by magnifying graticule to the nearest 25 microvolts, averaged for up to 3 normal and 3 RBBB complexes, and compared by paired t test. RBBB was associated with an increase in initial QRS forces (RV1, RV2, and QV6) but significant decreases in mean mid-QRS amplitudes that reflect left ventricular depolarization (RaVL [-75 microvolts], SV1 [-389 microvolts], SV3 [-617 microvolts], RV5 [-100 microvolts], and RV6 [-123 microvolts]). All late QRS forces were increased with RBBB (R'V1, SV5, SI). As a result, combined voltages used for LVH criteria were significantly reduced by RBBB: Sokolow-Lyon voltage decreased from 1520 +/- 739 to 1014 +/- 512 microvolts (p < 0.001), and Cornell voltage decreased from 1438 +/- 683 to 746 +/- 399 microvolts (p < 0.001). RBBB is associated with significant reduction in "left ventricular" QRS amplitudes of the standard ECG, consistent with cancellation, rather than unmasking, of left ventricular mid-QRS forces by altered septal and delayed right ventricular depolarization. Because QRS voltages that are routinely combined for the detection of LVH are reduced in RBBB, standard LVH criteria will perform with lower sensitivity in patients with RBBB.

Right Bundle Branch Block in Acute Myocardial Infarction Treated by Primary Coronary Angioplasty and Stenting

Patients with right bundle branch block (RBBB) in acute myocardial infarction (AMI) have a significantly higher mortality rate even with the advent of thrombolytic therapy. This study was undertaken to assess the impact of primary percutaneous transluminal coronary angioplasty (PTCA) and stenting on the outcome of patients with RBBB in AMI. A total of 600 patients with AMI who underwent primary PTCA and stenting (rate: 61%) < 12 hours of onset were studied. A 12-lead ECG was obtained at least every 6 hours. Serial creatine kinase was measured, and left ventricular ejection fraction was obtained during the hospital stay. Among 600 patients with AMI, 94 patients (15.7%) had RBBB; it was persistent in 31 (33%) and transient in 63 (67%). In-hospital mortality rate was 7.3% in patients without RBBB, 7.9% in transient RBBB, and 25.8% in persistent RBBB (p < 0.02). The incidence of heart failure was 26.5% in those without RBBB, 34.9% in transient RBBB, and 58.1% in persistent RBBB (p < 0.001). There was no significant difference among these 3 groups in ventricular arrhythmias and complete atrioventricular block. Peak creatine kinase was 3,214+/-2,293 U/L in those without RBBB, 4,558+/-3,316 U/L in transient RBBB (p < 0.001), and 5,635+/-3,920 U/L in persistent RBBB (p < 0.001). Left ventricular ejection fraction was 50+/-11% in those without RBBB, 47+/-11% in transient RBBB (p < 0.05), and 42+/-13% in persistent RBBB (p < 0.001). Patients with AMI treated by primary PTCA and stenting had an increased incidence of transient RBBB, especially following reperfusion therapy, although the clinical outcome was similar to that of those without RBBB. In contrast, there was no satisfactory improvement in clinical outcomes in those with persistent RBBB.

Effects of right bundle branch block during atrioventricular nodal reentrant tachycardia

Background The significant role of bundle branch block during atrioventricular nodal reentrant tachycardia (AVNRT) is not clear. The purposes of this study were to study the effects of complete right bundle branch block (RBBB) on electrophysiological parameters during AVNRT and to define the significance of complete RBBB during AVNRT. Methods and results According to characteristics of electrocardiogram during sinus rhythm and AVNRT, 50 patients who underwent catheter ablation for slow–fast AVNRT were divided into three groups. Group I included 20 patients who had narrow QRS (≤110 ms) during sinus rhythm and AVNRT. Group II included 18 patients who had persistent RBBB (≥120 ms) during sinus rhythm and AVNRT. Group III included 12 patients who had narrow QRS during sinus rhythm, but they had narrow QRS and transient RBBB during AVNRT. The atrio-His (AH) interval (296±60 vs. 288±75 ms), His-ventricular (HV) interval (36±11 vs. 35±11 ms), His-atrial (HA) interval (72±24 vs. 71±28 ms), VA HRA interval (defined as the interval between the onset of ventricular depolarization and the onset of atrial activity of right high atrium; 34±24 vs. 37±25 ms), VA CSO interval (defined as the interval between the onset of ventricular depolarization and the onset of atrial activity of coronary sinus ostium; 13±28 vs. 26±23 ms) and tachycardia cycle length (TCL; 368±67 vs. 359±73 ms) during AVNRT were similar between group I and group II (all P>0.05). In group III, the AH interval (255±81 vs. 246±83 ms), HV interval (44±5 vs. 42±11 ms), HA interval (66±19 vs. 70±15 ms), VA HRA interval (27±15 vs. 29±16 ms), VA CSO interval (23±25 vs. 21±25 ms) and TCL (322±76 vs. 316±77 ms) were not significantly different between AVNRT with narrow QRS and those with transient RBBB (all P>0.05). Conclusions Persistent RBBB and transient RBBB have no significant effects on the electrophysiological parameters during AVNRT. These findings suggest that RBBB might not influence the conduction of lower common pathway or the circuit of AVNRT.

Incidence, clinical characteristics, and prognostic significance of right bundle-branch block in acute myocardial infarction: a study in the thrombolytic era.

Whereas the significance of right bundle-branch block (RBBB) in acute myocardial infarction was extensively studied in the prethrombolytic era, a possible change in the overall incidence and meaning of RBBB as a consequence of thrombolytic therapy is not well known. A multicenter, prospective study of 1238 patients consecutively diagnosed with acute myocardial infarction and admitted to three coronary care units was conducted. ECGs during the acute phase and clinical events until discharge and 1-year follow-up were monitored. In the 135 (10.9%) patients in whom RBBB was found, there were 51 (37.8%) new cases, 46 (34.1%) old cases, and 38 (28.1%) cases with an indeterminate time of origin. New RBBB was permanent in 26 and transient in 25 patients. RBBB was isolated in 76 (56%) and bifascicular in the remaining 59 (44%) patients. The following complications were more frequently associated with RBBB than non-RBBB patients: heart failure, 24% versus 46% (P<.001); use of pacemaker because of atrioventricular block, 3.6% versus 11% (P<.001); and 1-year mortality, 17.6% versus 40.7% (P<.001). Early mortality was significantly higher for new RBBB (43.1%, P<.001) than for old (15.5%) and indeterminate (15.3%) RBBB. These figures for 1-year mortality were 58.8% (P<.001), 35.5 (P<.01), and 23% (NS), respectively. Permanent and transient RBBB had different mortality rates: early mortality, 76% versus 8%, and 1-year mortality, 84% versus 32% (P<.001 for both). For isolated RBBB versus bifascicular block, early mortality was 14.4% versus 40.6%, and 1-year mortality was 30.2% versus 54.2% (P<.05 for both). Multivariate analysis showed an independent prognostic value of RBBB for early and 1-year mortality. The overall meaning of RBBB in acute myocardial infarction has not changed in the thrombolytic era, although a higher rate of new and transient RBBB and a lower rate of bifascicular block may represent a beneficial effect of thrombolytic therapy.

Right bundle-branch block. Occurrence following nonpenetrating chest trauma without evidence of cardiac contusion

RIGHT bundle-branch block (RBBB) is an unusual complication of non-penetrating trauma to the chest. Rankin and Patterson¹in 1952 and Parmley et al²in 1958 described transient intraventricular conduction defects that they concluded were due to myocardial contusion. We report a case of transient RBBB that developed following nonpenetrating chest trauma without myocardial injury as evidenced by serial ECGs, technetium Tc 99m pyrophosphate scan, and cardiac enzyme values. <h3>Report of a Case</h3> A 55-year-old man who had been previously healthy was seen in the emergency room of the Houston Veterans Administration Hospital following an automobile accident in which he had sustained blunt trauma to the anterior chest wall. His only complaint was of nonradiating pleuritic chest pain. The patient was in mild distress. The cardiac apical impulse was in the sixth intercostal space of the midclavicular line. His pain increased following firm palpation of the anterior chest wall. Otherwise,

Right Bundle-Branch Block

RIGHT bundle-branch block (RBBB) is an unusual complication of non-penetrating trauma to the chest. Rankin and Patterson¹in 1952 and Parmley et al²in 1958 described transient intraventricular conduction defects that they concluded were due to myocardial contusion. We report a case of transient RBBB that developed following nonpenetrating chest trauma without myocardial injury as evidenced by serial ECGs, technetium Tc 99m pyrophosphate scan, and cardiac enzyme values. <h3>Report of a Case</h3> A 55-year-old man who had been previously healthy was seen in the emergency room of the Houston Veterans Administration Hospital following an automobile accident in which he had sustained blunt trauma to the anterior chest wall. His only complaint was of nonradiating pleuritic chest pain. The patient was in mild distress. The cardiac apical impulse was in the sixth intercostal space of the midclavicular line. His pain increased following firm palpation of the anterior chest wall. Otherwise,

Prognostic factors in right bundle-branch block complicating acute myocardial infarction.

Summary: Seventy patients with right bundle-branch block (RBBB), comprising 6% of 1083 patients with acute myocardial infarction, were admitted to our coronary care unit (CCU) over a five-year period. Thirty-eight of them died in hospital. Their prognosis was not altered significantly by the presence of complete heart block (CHB), bilateral bundle-branch block or the site of infarction and serum enzyme levels. Hospital mortality was lower (p<0.015) among eight patients with transient RBBB of whom one died. The high mortality appeared to be due mainly to extensive infarction. All 32 survivors were followed from two to 50 months and 15 have died. Four patients who had had bilateral bundle-branch block or CHB died suddenly. Although no sudden deaths occurred in those with RBBB alone the mortality at six, 12 and 18 months did not differ significantly from patients with bilateral bundle-branch block. Of the 17 patients still alive eleven have persistent RBBB, one has bilateral bundle-branch block, one has required permanent pacing for Stokes-Adams attacks and four have a QRS complex of normal duration. The late sudden deaths suggest that permanent pacing may have a place in the management of patients with bilateral bundle-branch block surviving infarction.