Defining left bundle branch block according to the new 2021 European Society of Cardiology criteria

Correctly diagnosing left bundle branch block (LBBB) is fundamental, as LBBB occurs frequently in heart failure and may trigger a vicious cycle of progressive left ventricular dysfunction. Moreover, a correct diagnosis of LBBB is pivotal to guide cardiac resynchronisation therapy. Since the LBBB diagnostic criteria were recently updated by the European Society of Cardiology (ESC), we assessed their diagnostic accuracy compared with the previous ESC 2013 definition. We further discuss the complexity of defining LBBB within the context of recent insights into the electromechanical pathophysiology of LBBB.     

A single-centre prospective evaluation of left bundle branch area pacemaker implantation characteristics

BackgroundLeft bundle branch area pacing (LBBAP) has recently been introduced as a physiological pacing technique with synchronous left ventricular activation. It was our aim to evaluate the feasibility and learning curve of the technique, as well as the electrical characteristics of LBBAP.Methods and resultsLBBAP was attempted in 80 consecutive patients and electrocardiographic characteristics were evaluated during intrinsic rhythm, right ventricular septum pacing (RVSP) and LBBAP. Permanent lead implantation was successful in 77 of 80 patients (96%). LBBAP lead implantation time and fluoroscopy time shortened significantly from 33 ± 16 and 21 ± 13 min to 17 ± 5 and 12 ± 7 min, respectively, from the first 20 to the last 20 patients. Left bundle branch (LBB) capture was achieved in 54 of 80 patients (68%). In 36 of 45 patients (80%) with intact atrioventricular conduction and narrow QRS, an LBB potential (LBB_pot) was present with an LBB_pot to onset of QRS interval of 22 ± 6 ms. QRS duration increased significantly more during RVSP (141 ± 20 ms) than during LBBAP (125 ± 19 ms), compared to 130 ± 30 ms without pacing. An even clearer difference was observed for QRS area, which increased significantly more during RVSP (from 32 ± 16 µVs to 73 ± 20 µVs) than during LBBAP (41 ± 15 µVs). QRS area was significantly smaller in patients with LBB capture compared to patients without LBB capture (43 ± 18 µVs vs 54 ± 21 µVs, respectively). In patients with LBB capture (n = 54), the interval from the pacing stimulus to R‑wave peak time in lead V6 was significantly shorter than in patients without LBB capture (75 ± 14 vs 88 ± 9 ms, respectively).ConclusionLBBAP is a safe and feasible technique, with a clear learning curve that seems to flatten after 40–60 implantations. LBB capture is achieved in two-thirds of patients. Compared to RVSP, LBBAP largely maintains ventricular electrical synchrony at a level close to intrinsic (narrow QRS) rhythm.Supplementary InformationThe online version of this article (10.1007/s12471-022-01679-7) contains supplementary material, which is available to authorized users.     

Initial experience,feasibility and safety of permanent left bundle branch pacing: results from a prospective single-centre study

BackgroundLeft bundle branch (LBB) pacing is a novel pacing technique which may serve as an alternative to both right ventricular pacing for symptomatic bradycardia and cardiac resynchronisation therapy (CRT). A substantial amount of data is reported by relatively few, highly experienced centres. This study describes the first experience of LBB pacing in a high-volume device centre.MethodsSuccess rates (i.e. the ability to achieve LBB pacing), electrophysiological parameters and complications at implant and up to 6 months of follow-up were prospectively assessed in 100 consecutive patients referred for various pacing indications.ResultsThe mean age was 71 ± 11 years and 65% were male. Primary pacing indication was atrioventricular (AV) block in 40%, CRT in 42%, and sinus node dysfunction or refractory atrial fibrillation prior to AV node ablation in 9% each. Baseline left ventricular ejection fraction was < 50% in 57% of patients, mean baseline QRS duration 145 ± 34 ms. Overall LBB pacing was successful in 83 of 100 (83%) patients but tended to be lower in patients with CRT pacing indication (69%, p = ns). Mean left ventricular activation time (LVAT) during LBB pacing was 81 ms and paced QRS duration was 120 ± 19 ms. LBB capture threshold and R‑wave sense at implant was 0.74 ± 0.4 mV at 0.4 ms and 11.9 ± 5.9 V and remained stable at 6‑month follow-up. No complications occurred during implant or follow-up.ConclusionLBB pacing for bradycardia pacing and resynchronisation therapy can be easily adopted by experienced implanters, with favourable success rates and safety profile.     

Aortic valve implantation-induced conduction block as a framework towards a uniform electrocardiographic definition of left bundle branch block

IntroductionNew-onset left bundle branch block (LBBB) following transcatheter or surgical aortic valve replacement (LBBB_AVI) implies a proximal pathogenesis of LBBB. This study compares electrocardiographic characteristics and concordance with LBBB definitions between LBBB_AVI and non-procedure-induced LBBB controls (LBBB_control).MethodsAll LBBB_AVI patients at Ghent University Hospital between 2013 and 2019 were enrolled in the study. LBBB_AVI patients were matched for age, sex, ischaemic heart disease and ejection fraction to LBBB_control patients in a 1:2 ratio. For inclusion, a non-strict LBBB definition was used (QRS duration ≥ 120 ms, QS or rS in V1, absence of Q waves in V5-6). Electrocardiograms were digitally analysed and classified according to three LBBB definitions: European Society of Cardiology (ESC), Strauss and American Heart Association (AHA).ResultsA total of 177 patients (59 LBBB_AVI and 118 LBBB_control) were enrolled in the study. LBBB_AVI patients had more lateral QRS notching/slurring (100% vs 85%, p = 0.001), included a higher percentage with a QRS duration ≥ 130 ms (98% vs 86%, p = 0.007) and had a less leftward oriented QRS axis (−15° vs −30°, p = 0.013) compared to the LBBB_control group. ESC and Strauss criteria were fulfilled in 100% and 95% of LBBB_AVI patients, respectively, but only 18% met the AHA criteria. In LBBB_control patients, concordance with LBBB definitions was lower than in the LBBB_AVI group: ESC 85% (p = 0.001), Strauss 68% (p < 0.001) and AHA 7% (p = 0.035). No differences in electrocardiographic characterisation or concordance with LBBB definitions were observed between LBBB_AVI and LBBB_control patients with lateral QRS notching/slurring.ConclusionNon-uniformity exists among current LBBB definitions concerning the detection of proximal LBBB. LBBB_AVI may provide a framework for more consensus on defining proximal LBBB.Supplementary InformationThe online version of this article (10.1007/s12471-021-01565-8) contains supplementary material, which is available to authorized users.     

Patient-reported health status prior to cardiac resynchronisation therapy identifies patients at risk for poor survival and prolonged hospital stays

Background

Patient-reported factors have largely been neglected in search of predictors of response to cardiac resynchronisation therapy (CRT). The current study aimed to examine the independent value of pre-implantation patient-reported health status in predicting four-year survival and cardiac-related hospitalisation of CRT patients.

Methods

Consecutive patients (N = 139) indicated to receive a first-time CRT-defibrillator at the University Medical Center Utrecht were asked to complete a set of questionnaires prior to implantation. The Kansas City Cardiomyopathy Questionnaire (KCCQ) was used to assess heart failure-specific health status. Data on patients’ demographic, clinical and psychological characteristics at baseline, and on cardiac-related hospitalisations and all-cause deaths during a median follow-up of 3.9 years were obtained from purpose-designed questionnaires and patients’ medical records.

Results

Results of multivariable Cox regression analyses showed that poor patient-reported health status (KCCQ score < 50) prior to implantation was associated with a 2.5-fold increased risk of cardiac hospitalisation or all-cause death, independent of sociodemographic, clinical and psychological risk factors (adjusted hazard ratio 2.46, 95 % confidence interval (CI) 1.30–4.65). Poor health status was not significantly associated with the absolute number of cardiac-related hospital admissions, but with the total number of days spent in hospital during follow-up (adjusted incidence rate ratio 3.20, 95 % CI 1.88–5.44).

Conclusions

Patient-reported health status assessed prior to CRT identifies patients at risk for poor survival and prolonged hospital stays, independent of traditional risk factors. These results emphasise the importance of incorporating health status measures in cardiovascular research and patient management. Heart failure patients reporting poor health status should be identified and offered appropriate additional treatment programs.     

Cardiac resynchronisation therapy and the role of optimal device utilisation

Despite established selection criteria, 30 to 40% of patients do not respond to cardiac resynchronisation therapy. By optimising programming of the device response to cardiac resynchronisation, therapy can be improved. (Neth Heart J 2009;17:354–7.)     

Selective left bundle branch pacing for pediatric complete heart block

Traditionally Right Ventricle has been the preferred site of pacing for the management of symptomatic brady-arrhythmias. The deleterious effect of chronic RV pacing has been shown by several studies. This has generated interest into a novel pacing strategy called physiological pacing wherein the His bundle or the left bundle is paced directly with 4.1 F pacing lead. Herewith we are reporting a case of congenital complete heart block in a 13-year-old child for whom selective left bundle branch pacing was done. This physiological pacing will ensure a synchronized contraction of the ventricles thereby avoiding the deleterious effect of RV pacing.     

Right bundle branch block pattern after uncomplicated right ventricular outflow tract pacing in a patient with a left sided superior vena cava and corrected tetralogy of Fallot

Usually an electrocardiogram after right ventricular (RV) pacing should yield left bundle branch block (LBBB) pattern. However, the presence of right bundle branch block (RBBB) pattern after pacemaker implantation should alert the physician to a malposition of lead. We report a case of 18-year-old female who underwent dual chamber pacemaker implantation and had RBBB pattern post implantation. Detailed evaluation revealed an uncomplicated right ventricular outflow tract pacing. The possible causes of this abnormal pattern after an uncomplicated RV pacing are also reviewed.     

Tailoring cardiac resynchronisation therapy to non-left bundle branch block: Successful cardiac resynchronisation for right bundle branch block with left posterior fascicular block without implantation of a left ventricular lead

Despite advances, cardiac resynchronisation therapy (CRT) remains fundamentally orientated to the dyssynchrony of left bundle branch block (LBBB), in which septo-lateral electrical and mechanical delays predominate. For non-LBBB patients response rates to conventional CRT are lower and mortality and rehospitalisation rates are not reduced. Despite this, alternative approaches which tailor CRT to the differing dyssynchrony patterns of non-LBBB have yet to be developed. In the specific non-LBBB subgroup of right bundle branch block (RBBB) with left posterior fascicular block (LPFB), ventricular conduction via the left anterior fascicle results in a unique early lateral, and late septal depolarisation, or lateral to septal left ventricular (LV) delay, an electrical sequence which is followed mechanically. This latero-septal delay is somewhat the reverse of LBBB and was overcome by fusing right ventricular (RV) septal pacing with intrinsic conduction via the left anterior fascicle, achieving successful resynchronisation without implantation of a left ventricular lead. A stable fusion pattern was achieved via the ‘Negative AV Hysteresis with Search’ algorithm (Abbott, St Paul, Minnesota). Improvement in all standard CRT response indices was achieved at 3 months: QRS duration was reduced from 153 to 106 ms, ejection fraction increased from 14 to 32%, and LV end-systolic and end-diastolic diameters reduced by 19% and 12.5% respectively. NYHA class improved from III-IV to class II. Cardiac resynchronisation for RBBB with LPFB can be successfully achieved with a standard pacemaker or defibrillator without left ventricular lead implantation by fusing RV septal-only pacing with intrinsic conduction.     

Association of apical rocking with super-response to cardiac resynchronisation therapy

Background

Super-responders to cardiac resynchronisation therapy (CRT) show an exceptional improvement in left ventricular ejection fraction (LVEF). Previous studies showed that apical rocking was independently associated with echocardiographic response to CRT. However, little is known about the association between apical rocking and super-response to CRT.

Objectives

To determine the independent association of LV apical rocking with super-response to CRT in a large cohort.

Methods

A cohort of 297 consecutive heart failure patients treated with primary indication for CRT-D were included in an observational registry. Apical rocking was defined as motion of the left ventricular (LV) apical myocardium perpendicular to the LV long axis. ‘Super-response’ was defined by the top quartile of LVEF response based on change from baseline to follow-up echocardiogram. Best-subset regression analysis identified predictors of LVEF super-response to CRT.

Results

Apical rocking was present in 45 % of patients. Super-responders had an absolute mean LVEF increase of 27 % (LVEF 22.0 % ± 5.7 at baseline and 49.0 % ± 7.5 at follow-up). Apical rocking was significantly more common in super-responders compared with non-super-responders (76 and 34 %, P < 0.001). In univariate analysis, female gender (OR 2.39, 95 % CI 1.38–4.11), lower LVEF at baseline (OR 0.91 95 % CI 0.87–0.95), non-ischaemic aetiology (OR 4.15, 95 % CI 2.33–7.39) and apical rocking (OR 6.19, 95 % CI 3.40–11.25) were associated with super-response. In multivariate analysis, apical rocking was still strongly associated with super-response (OR 5.82, 95 % CI 2.68–12.61). Super-responders showed an excellent clinical prognosis with a very low incidence of heart failure admission, cardiac mortality and appropriate ICD therapy.

Conclusion

Apical rocking is independently associated with super-response to CRT.

Electronic supplementary material

The online version of this article (doi:10.1007/s12471-015-0768-4) contains supplementary material, which is available to authorized users.     

Haemodynamic evaluation of alternative left ventricular endocardial pacing sites in clinical non-responders to cardiac resynchronisation therapy

Introduction

Non response to cardiac resynchronisation therapy (CRT) may be related to the position of the coronary sinus lead.

Methods

We studied the acute haemodynamic response (AHR) from alternative left ventricular (LV) endocardial pacing sites in clinical non-responders to CRT. AHR and the interval from QRS onset to LV sensing (Q-LV interval) from four different endocardial pacing sites were evaluated in 24 clinical non-responders. A rise in LVdP/dtmax ≥ 15 % from baseline was considered a positive AHR. We also compared the AHR from endocardial with the corresponding epicardial lead position.

Results

The implanted system showed an AHR ≥ 15 % in 5 patients. In 9 of the 19 remaining patients, AHR could be elevated to ≥ 15 % by endocardial LV pacing. The optimal endocardial pacing site was posterolateral. There was no significant difference in AHR between the epicardial and the corresponding endocardial position. The longest Q-LV interval corresponded with the best AHR in 12 out of the 14 patients with a positive AHR, with an average Q-LV/QRS width ratio of 90 %.

Conclusions

Acute haemodynamic testing may indicate an alternative endocardial pacing site with a positive AHR in clinical non-responders. The Q-LV interval is a strongly correlated with the optimal endocardial pacing site. Endocardial pacing opposite epicardial sites does not result in a better AHR.     

Identifying delayed left ventricular lateral wall activation in patients with non-specific intraventricular conduction delay using coronary venous electroanatomical mapping

Background

Delayed left ventricular (LV) lateral wall activation is considered the electrical substrate that characterises patients suitable for cardiac resynchronisation therapy (CRT). Although typically associated with left bundle branch block, delayed LV lateral wall activation may also be present in patients with non-specific intraventricular conduction delay (IVCD). We assessed LV lateral wall activation in a cohort of CRT candidates with IVCD using coronary venous electroanatomical mapping, and investigated whether baseline QRS characteristics on the ECG can identify delayed LV lateral wall activation in this group of patients.

Methods

Twenty-three consecutive CRT candidates with IVCD underwent intra-procedural coronary venous electroanatomical mapping using EnSite NavX. Electrical activation time was measured in milliseconds from QRS onset and expressed as percentage of QRS duration. LV lateral wall activation was considered delayed if maximal activation time measured at the LV lateral wall (LVLW-AT) exceeded 75 % of the QRS duration. QRS morphology, duration, fragmentation, axis deviation, and left anterior/posterior fascicular block were assessed on baseline ECGs.

Results

Delayed LV lateral wall activation occurred in 12/23 patients (maximal LVLW-AT = 133 ± 20 ms [83 ± 5 % of QRS duration]). In these patients, the latest activated region was consistently located on the basal lateral wall. QRS duration, and prevalence of QRS fragmentation and left/right axis deviation, and left anterior/posterior fascicular block did not differ between patients with and without delayed LV lateral wall activation.

Conclusion

Coronary venous electroanatomical mapping can be used at the time of CRT implantation to determine the presence of delayed LV lateral wall activation in patients with IVCD. QRS characteristics on the ECG seem unable to identify delayed LV lateral wall activation in this subgroup of patients.     

Cardiac resynchronisation therapy: results from daily practice in Rijnstate Hospital, Arnhem

BackgroundCardiac resynchronisation therapy (CRT) is an effective treatment to improve the clinical outcome of selected patients with heart failure. Clinical trials have studied clinical outcome and reported clinical improvements, but clinical consequences and results in daily practice are less well known. We evaluated clinical outcome in all patients with CRT implantation in our centre. MethodsData of 119 consecutive patients who met the criteria for CRT implantation in Rijnstate Hospital, Arnhem in the period 28 November 2000 until 1 January 2006 were collected. We analysed implantation procedure, hospitalisation for heart failure or other causes, mortality and device-related events. ResultsIn total 119 patients (83 men, 36 women; mean age 69 years) were eligible for CRT. Before implantation they had received optimal pharmacological therapy. Implantation was successful in 97% of patients. Procedural-related complications were seen in eight patients. During follow-up, 22 patients (18.5%: 14 men, 8 women) died. Causes of death were heart failure (11 patients), sudden cardiac death (4 patients) and noncardiac death (7 patients). Hospitalisation occurred 81 times, of which 77 for cardiac reasons. In follow-up the estimated five-year cumulative survival was 70%. ConclusionThis retrospective study from a single centre showed a high procedural success rate, low prevalence of complications and low mortality in comparison to other studies. Despite better functional capacity, the hospitalisation rate due to heart failure was high. (Neth Heart J 2009;17:6-8.)     

New insights in LV torsion for the selection of cardiac resynchronisation therapy candidates

Recent literature indicates that torsion of the left ventricle (LV) is a promising predictor for response to cardiac resynchronisation therapy (CRT). Among patients with severe heart failure, 45 to 75% of patients show rigid body rotation, where the base and apex rotate in the same direction, instead of normal, opposite rotation. The occurrence of this phenomenon seems to be a good indicator for response to CRT. From this review, it can be concluded that LV torsion might be a welcome addition to current selection criteria.     

Left ventricular endocardial pacing in cardiac resynchronisation therapy: Moving from bench to bedside

In cardiac resynchronisation therapy, failure to implant a left ventricular lead in a coronary sinus branch has been reported in up to 10% of cases. Although surgical insertion of epicardial leads is considered the standard alternative, this is not without morbidity and technical limitations. Endocardial left ventricular pacing can be an alternative as it has been associated with a favourable acute haemodynamic response compared with epicardial pacing in both animal and human studies. In this paper, we discuss left ventricular endocardial pacing and compare it with epicardial surgical implantation. Ease of application and procedural complications and morbidity compare favourably with epicardial surgical techniques. However, with limited experience, the most important concern is the still unknown long-term risk of thromboembolic complications. Therefore, for now endovascular implants should remain reserved for severely symptomatic heart failure patients and patients at high surgical risk of failed coronary sinus implantation.     

心脏彩超评估高血压左心室肥厚伴左心衰竭患者心功能的临床价值及与NYHA分级的关系研究

目的:探讨心脏彩超评估高血压左心室肥厚(LVH)伴左心衰竭患者心功能的临床价值,分析其超声指标与美国纽约心脏病协会(NYHA)分级的相关性。方法:选择2017年5月至2018年5月我院收治的127例高血压LVH伴左心衰竭患者为观察组,根据NYHA分级将其分为NYHAⅡ级组(41例)、Ⅲ级组(47例)、Ⅳ级组(39例),另选择100例体检的健康志愿者为对照组。所有受试者均接受心脏彩超获得相关参数[左心房内径(LAD)、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、左心室短轴缩短率(LVFS)、左心室后壁厚度(LVPWT)、室间隔厚度(IVST)、左心室射血分数(LVEF)、左心室舒张早期充盈峰最大充盈速度/舒张晚期充盈峰最大峰值速度(E/A)比值、Tei指数],分析心脏彩超相关参数与NYHA分级之间相关性。结果:观察组患者LAD、LVEDD、LVESD、LVPWT、IVST、Tei指数高于对照组(P0.05),LVFS、LVEF、E/A比值低于对照组(P0.05)。Tei指数随着NYHA分级增高而增高(P0.05),LVFS、LVEF、E/A比值随着NYHA分级增高而降低(P0.05)。Spearman秩相关分析结果显示,Tei指数与NYHA分级呈正相关(rs=0.398,P0.05),LVFS、LVEF、E/A比值与NYHA分级呈负相关(rs=-0.285,-0.442,-0.305,P0.05)。结论:高血压LVH伴左心衰竭患者发生明显左室肥厚和左心功能降低,心脏彩超可准确评估高血压LVH伴左心衰竭患者的心功能和病情严重程度,且部分心脏彩超相关参数与NYHA分级相关。     

Six months clinical outcome comparison between quadripolar and bipolar left ventricular leads in cardiac resynchronization therapy: A prospective,non-randomized,single-centre observational study

Background and objectivesQuadripolar left ventricular (LV) leads in cardiac resynchronization therapy (CRT) offer multi-vector pacing with different pacing configurations and hence enabling LV pacing at most suitable site with better lead stability. We aim to compare the outcomes between quadripolar and bipolar LV lead in patients receiving CRT.MethodsIn this prospective, non-randomized, single-center observational study, we enrolled 93 patients receiving CRT with bipolar (BiP) (n = 31) and quadripolar (Quad) (n = 62) LV lead between August 2016 to August 2019. Patients were followed for six months, and outcomes were compared with respect to CRT response (defined as ≥5% absolute increase in left ventricle ejection fraction), electrocardiographic, echocardiographic parameters, NYHA functional class improvement, and incidence of LV lead-related complication.ResultsAt the end of six months follow up, CRT with quadripolar lead was associated with better response rate as compared to bipolar pacing (85.48% vs 64.51%; p = 0.03), lesser heart failure (HF) hospitalization events (1.5 vs 2; p = 0.04) and better improvement in HF symptoms (patients with ≥1 NYHA improvement 87.09% vs 67.74%; p = 0.04). There were fewer deaths per 100 patient-year (6.45 vs 9.37; p = 0.04) and more narrowing of QRS duration (Δ12.56 ± 3.11 ms vs Δ7.29 ± 1.87 ms; p = 0.04) with quadripolar lead use. Lead related complications were significantly more with the use of bipolar lead (74.19% vs 41.94%; p = 0.02).ConclusionsOur prospective, non-randomized, single-center observational study reveals that patients receiving CRT with quadripolar leads have a better response to therapy, lesser heart failure hospitalizations, lower all-cause mortality, and fewer lead-related complications, proving its superiority over the bipolar lead.     

Atrial electrogram quality in single-pass defibrillator leads with floating atrial bipole in patients with permanent atrial fibrillation and cardiac resynchronization therapy

Many patients receiving cardiac resynchronization therapy (CRT) suffer from permanent atrial fibrillation (AF). Knowledge of the atrial rhythm is important to direct pharmacological or interventional treatment as well as maintaining AV-synchronous biventricular pacing if sinus rhythm can be restored. A single pass single-coil defibrillator lead with a floating atrial bipole has been shown to obtain reliable information about the atrial rhythm but has never been employed in a CRT-system. The purpose of this study was to assess the feasibility of implanting a single coil right ventricular ICD lead with a floating atrial bipole and the signal quality of atrial electrograms (AEGM) in CRT-defibrillator recipients with permanent AF.