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

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<0.001). V6RWPT during LBBAP (47±15ms) was significantly longer than V6RWPT in iRBBB (40±5ms) and cRBBB (39±7ms) (p<0.001). With LBBAP, V1RWPT (83±15ms) became delayed compared to iRBBB (74±9ms, p< 0.001), but remained shorter in comparison to cRBBB (98±17ms, p<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.

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.

Progressive left ventricular electro-mechanical remodelling in presence of left bundle branch block

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation Flanders (FWO)

Introduction

Recent cross-sectional studies suggest a relationship between persisting left bundle branch block (LBBB) and the extent of left ventricular (LV) electro-mechanical remodelling over time. However, when patients are referred for cardiac resynchronization therapy (CRT), temporal data during the sub-clinical phase of disease are often missing. A longitudinal study using an animal model would improve our understanding of the relationship between the onset of LBBB and the electro-mechanical remodelling.

Purpose

To investigate the progressive remodelling that develops over time in an animal model of LBBB.

Methods

Fifteen sheep were subjected to rapid DDD pacing (180 bpm; leads on right atrium and right ventricular free wall) in order to induce a LBBB-like conduction delay. All animals underwent an 8-week pacing protocol, whereas 5 of them were subjected to 16 weeks of pacing in total. Echocardiographic speckle tracking was used to assess circumferential strain of the septal and lateral wall. Septal and lateral wall thickness were measured at end-diastole. Cardiac magnetic resonance imaging was used to determine LV volumes and ejection fraction (LVEF). Examinations took place at baseline (before and after start of pacing), and after 8 and 16 weeks of pacing. All examinations were performed at a physiologic heart rate of 110 bpm.

Results

At baseline, DDD pacing induced an increase in QRS duration (+83%, p < 0.0001) and LBBB-like mechanical dyssynchrony, with mild early-systolic notching and preserved systolic shortening of the septal wall. Early lateral wall pre-stretch was followed by increasing systolic shortening. No acute changes in LV end-diastolic volume, LVEF or septal or lateral wall thickness were observed (all p > 0.05). After 8 weeks of DDD pacing, mechanical dyssynchrony worsened: septal notching increased, followed by reduced systolic shortening. After 16 weeks, the initial septal shortening was followed by profound stretching throughout systole. Lateral wall shortening was reduced compared to baseline (p < 0.05). QRS duration progressively increased by +15% (week 8) and +26% (week 16) (all p < 0.001). End-diastolic volumes had increased by +38% (week 8) and +74% (week 16), whereas LVEF had decreased by –35% (week 8) and –55% (week 16) (all p < 0.001). Septal wall thickness had reduced by –18% (week 8) and –29% (week 16), while lateral wall thickness had increased by +13% (week 8) and +24% (week 16) (all p < 0.05).

Conclusion

A persisting LBBB induces progressive changes in LV deformation patterns, and triggers morphological and electrical remodelling, strengthening the concept of LBBB-induced cardiomyopathy. In the clinic, patients with mild dysfunction should be closely monitored for potential disease progression in order to treat dyssynchrony as soon as guideline indications are reached. Further studies need to show if earlier CRT-implantation might prevent further LV deterioration. Abstract Figure.  Abstract Figure.

Strain-based staging classification of left bundle branch block-induced cardiac remodeling predicts reverse remodeling after cardiac resynchronization therapy

Background

Left bundle branch block (LBBB)-induced adverse remodeling is a gradual but largely unknown process, causing a variable degree of left ventricular (LV) dysfunction and response to cardiac resynchronization therapy (CRT). In LBBB patients with septal flash (SF), an electro-mechanical continuum of different speckle-tracking strain patterns was observed, with each pattern tightly correlating with the degree of LV remodeling and dysfunction (1) (Figure 1).

Purpose

In this study, we investigated the relationship between the staged LBBB strain patterns in CRT-eligible patients and their prediction with respect to reverse remodeling and clinical outcome.

Methods

This study enrolled CRT patients from the PREDICT-CRT study population (2). Inclusion criteria were LV ejection fraction (LVEF) ≤35%, QRS duration ≥120 ms, NYHA class II–IV, absence of right ventricular pacing and availability of speckle tracking strain imaging. All patients underwent an echocardiographic examination before and 12 months after CRT implant. LV volumes, strain and dyssynchrony were assessed. Mid-septal longitudinal strain curves were classified into 5 patterns (LBBB-0 through LBBB-4; Figure 1). Primary endpoint was all-cause mortality.

Results

The study involved 250 patients (mean age 64±10 years; 79% men) with a mean LVEF of 26±7%. LBBB was present in 220 (89%) patients and 206 (82%) patients had SF. Prior to CRT implant, a LBBB-0 pattern was observed in 33 (13%), LBBB-1 in 33 (13%), LBBB-2 in 39 (16%), LBBB-3 in 44 (18%) and LBBB-4 in 101 (40%) patients. Patients with LBBB-3 and -4 patterns more frequently had LBBB, lower LVEF, increased mechanical dyssynchrony and more prominent SF (p<0.001 for all) compared with patients with LBBB-0, -1 and -2 patterns. Across the stages, CRT resulted in a gradual volumetric response, ranging from no response in stage LBBB-0 patients (ΔLV end-systolic volume +7±33%; ΔLVEF −2±9%) to super-response in stage LBBB-4 patients (ΔLV end-systolic volume −40±29%; ΔLVEF +15±13%) (p<0.001 for all). Interestingly, following reverse remodeling, the LV function of stage LBBB-2, -3 and -4 patients improved to a similar LVEF of 38% (p=1.000) in this cohort. Patients in stage LBBB-0 had a significantly less favorable five-year outcome compared to those in stage LBBB≥1 (log-rank p=0.003). There was no difference in long-term outcome between stage LBBB-1 to −4 patients (log-rank p=0.510).

Conclusion

Strain-based LBBB staging predicts the extent of LV reverse remodeling in CRT patients. CRT did not translate into improved absolute survival in the more advanced stages, but the observed gradual volumetric response suggests that CRT corrects the LBBB-induced mortality.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Sequential left ventricular electro-mechanical changes in presence of left bundle branch block

Introduction

Recent cross-sectional studies suggest a relationship between persisting left bundle branch block (LBBB) and the extent of left ventricular (LV) electro-mechanical alterations over time. When patients are referred for cardiac resynchronization therapy (CRT), temporal data during the sub-clinical phase of disease is often missing. A longitudinal study using an animal model would provide a better understanding of the relationship between the onset of LBBB and the electro-mechanical changes.

Purpose

To investigate the sequential alterations in LV structure and function that develop over time in an animal model of LBBB.

Methods

Thirteen sheep were subjected to rapid DDD pacing (180 bpm; leads on right atrium and right ventricular free wall) in order to induce a LBBB-like conduction delay. All animals underwent an 8-week pacing protocol, whereas 4 of them were subjected to 16 weeks of pacing in total. Echocardiographic speckle tracking was used to assess circumferential strain of the septal and lateral wall. Septal and lateral wall thickness were measured at end-diastole. Cardiac magnetic resonance imaging was used to determine LV volumes and ejection fraction (LVEF). Examinations took place at baseline (before and after start of pacing), and after 8 and 16 weeks of pacing. All examinations were performed at a physiologic heart rate of 110 bpm.

Results

At baseline, DDD pacing induced an increase in QRS duration (+85%, p<0.0001) and LBBB-like mechanical dyssynchrony, with mild early-systolic notching and preserved systolic shortening of the septal wall. The lateral wall demonstrated early pre-stretch followed by increasing systolic shortening. No acute changes in LV end-diastolic volume, LVEF or septal or lateral wall thickness were observed (all p>0.05). After 8 weeks of DDD pacing, mechanical dyssynchrony worsened: septal notching increased, followed by reduced systolic shortening. After 16 weeks, the initial septal shortening was followed by profound stretching throughout systole. Lateral wall systolic shortening was reduced compared to baseline. QRS duration increased further by +12% (week 8) and +20% (week 16) (all p<0.001). End-diastolic volumes had increased by +39% (week 8) and +72% (week 16), whereas LVEF had decreased by −48% (week 8) and −56% (week 16) (all p<0.001). Septal wall thickness had reduced by −24% (week 8) and −33% (week 16), while lateral wall thickness had increased by +21% (week 8) and +30% (week 16) (all p<0.05).

Conclusion

A persisting LBBB-like conduction delay induces sequential changes in LV deformation patterns, and triggers morphological and electrical remodelling. These changes are similar to those observed in patients with LBBB and different degrees of LV dysfunction. Our data suggest a continuum due to the progression of LBBB-induced LV disease. In the clinic, patients with mild dysfunction should be closely monitored in order to treat dyssynchrony as soon as guideline indications are reached.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): This work was supported by a KU Leuven research grant

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

Introduction

New-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).

Methods

All 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).

Results

A 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.

Conclusion

Non-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 Information

The online version of this article (10.1007/s12471-021-01565-8) contains supplementary material, which is available to authorized users.

P309Aortic valve implantation-induced bundle branch block as a framework towards a more uniform electrocardiographic definition of left bundle branch block

INTRODUCTION

The electrocardiographic (ECG) pattern of true left bundle branch block (LBBB) has not been fully clarified and various definitions of LBBB exist. New-onset LBBB after transcatheter (TAVR) or surgical (SAVR) aortic valve replacement implies a proximal pathogenesis of LBBB and thus may provide a reference to characterize and define true LBBB.

PURPOSE

This study compares ECG characteristics in aortic valve implantation-induced LBBB (AVI-LBBB) to a non-procedural-induced LBBB control group (co-LBBB) in order to set a more homogenous definition for true LBBB.

METHODS

The study enrolled all patients with new-onset TAVR- and SAVR-induced LBBB between 2013 and 2019. AVI-LBBB was defined as new-onset persistent LBBB occurring within 24h after TAVR or SAVR. Patients were matched for age, sex, ischemic heart disease and left ventricular systolic function to randomly selected co-LBBB patients in a 1:2 ratio. For inclusion in both groups, a non-strict LBBB definition was used (QRSD ≥120ms, QS or rS in lead V1, absence of Q wave in leads V5-6). ECG characteristics were digitally analysed by the MUSE algorithm and confirmed by two experts. All ECG recordings were classified according to 4 different LBBB definitions: MADIT, European Society of Cardiology (ESC), Strauss and American Heart Association (AHA).

RESULTS

59 patients with AVI-LBBB (34 TAVR, 25 SAVR, median age 82 years, 42% male) were compared to 118 matched co-LBBB patients.

All patients with AVI-LBBB presented with QRS notching/slurring in the lateral leads, whereas this was present in only 85% of the co-LBBB group (p = 0.001). QRS duration (148ms vs 145ms, p = 0.074) and R wave peak time (58ms vs 62ms, p = 0.065) were not significantly different among both groups. AVI-LBBB was characterized by a more rightward QRS axis (-15° vs -30°, p = 0.013). When comparing AVI-LBBB to LBBB controls with QRS notching/slurring, a comparable QRS axis was observed.

Almost all AVI-LBBB patients met the MADIT (98%), ESC (100%) and Strauss (95%) definition. Only 18% of patients met the AHA definition, because of the low combined presence of QRS notching/slurring in all 4 lateral leads (54%) and because only 27% of patients had an R wave peak time &gt;60ms in both leads V5-6.

In the co-LBBB group, adherence to the different definitions was significantly lower compared to the AVI-LBBB group: MADIT 86% (p = 0.007), ESC 85% (p = 0.001), Strauss 68% (p &lt; 0.001) and AHA 7% (p = 0.035). Lower presence of lateral notching/slurring and more patients with smaller QRS duration (QRS duration ≥130ms, 86% vs 98%, p = 0.007) in the co-LBBB group explain these results.

CONCLUSIONS

Discordance exists between various definitions in scoring AVI-LBBB. Our data show that presence of QRS notching/slurring in the lateral leads is a crucial feature of proximal LBBB, rather than QRS duration and R wave peak time. The AVI-LBBB population provides a framework towards a more uniform definition and criteria for assessing true, proximal LBBB.

P782 Septal flash is a prevalent and early dyssynchrony marker in transcatheter aortic valve replacement-induced left bundle branch block

CONCLUSION

SF as dyssynchrony marker develops early after TAVR-induced LBBB and is much more prevalent than the classical strain-based dyssynchrony pattern and IVMD.

Our findings from the control population suggest that progressive LBBB-induced LV remodeling (septal thinning and relative lateral thickening) may be required for a ‘classical dyssynchrony strain pattern’ or significant IVMD to occur in TAVR-LBBB patients, but longitudinal follow-up studies in TAVR-LBBB patients are required as proof-of-concept.

Abstract P782 Figure 1

P1554 Assessment of functional mitral regurgitation with leg lift and exercise echocardiography using the average pixel intensity method

Background

Dynamic changes in functional mitral regurgitation (FMR) during exercise echocardiography were shown to be of prognostic value. However grading of FMR is challenging, especially during exercise echocardiography and therefore questioning its applicability in clinical practice. We recently introduced and validated the Average Pixel Intensity (API) for grading MR based on the pixel intensity of the continuous wave Doppler signal. In the current study we investigate the use of the API method using leg lift and exercise echocardiography in FMR.

Methods

We prospectively included 50 heart failure patients (mean ejection fraction 36%) in sinus rhythm with different grades of pure, FMR. After assessment of FMR severity at rest, the same acquisitions were repeated during leg lift and exercise echocardiography. FMR was assessed using the API method, color Doppler and quantitative grading methods (proximal isovelocity surface area (PISA) and vena contracta width (VCW)).

Results

The API method could be performed in all patients (100%) with leg lift (n = 50) and in 94% of the patients undergoing exercise echocardiography (n = 44), which was more than PISA and VCW (p &lt; 0.001).

During leg lift, there was a small but significant increase on visual color Doppler grading (grade 1.93 to 2.11 (p = 0.004); increase of FMR in 35% of patients, and no difference in 65%). For API, we found the same significant increase (93 to 101 au), however, API values showed increase of MR in 62% and decrease of FMR in 20%.

During exercise echocardiography, we found no differences in color Doppler grade and API in the overall cohort (p 0.252 and p 0.832, respectively), despite 62% of patients showing some degree of increase in API during leg lift. On multivariate analysis, no specific echo parameter could be identified as independent predictor of API increase.

Conclusions

The novel API method is highly feasible for assessing dynamic FMR and may be of added value for in this setting, allowing the detection of even small increments of FMR severity.

In the current study, we found only mild increases of FMR during exercise echocardiography. Leg lift testing however proved to be a simple and quick loading approach that induced a significant rise in FMR compared to exercise echocardiography. The prognostic relevance of the findings during leg lift remains to be determined.

P290 Differences in cardiac dimensions in mitral valve prolapse with or without Barlow phenotype

Background

Mitral valve prolapse (MVP) is a common cause of chronic mitral regurgitation (MR). Barlow’s disease (BD) and fibro-elastic deficiency (FED) are two major entities of MVP affecting the connective tissue of the mitral valve, but both have a different underlying pathophysiology and phenotype. In some connective tissue diseases (CTD), it has been suggested that ventricular dysfunction occurs despite absence of MR, suggesting that CTD directly involve the myocardium. We therefore investigated whether patients with BD have different cardiac dimensions compared to FED, after correcting for MR severity grade.

Methods

134 patients with MVP and chronic MR were prospectively included. MR was graded carefully by echocardiography using a multi-parametric approach. The morphology of the mitral valve prolapse was specified as definite Barlow (n = 45) or non-Barlow (n = 89; FED, flail leaflet or unspecified etiology) by two experienced echocardiographers.

Results

In our cohort, MR was significantly more severe in the non-Barlow group compared to typical BD group (regurgitant volume (RV) 51 vs 33 ml, p = 0.021; right ventricular systolic pressure, 40 vs 34 mmHg, p= 0.05, left atrial volume index, 51 vs 42 ml/m², p = 0.07, respectively).

However, there was a trend towards higher left ventricular end-diastolic diameter index (LVEDDi, 27.7 vs 29 mm, p = 0.07) and a significantly higher end-diastolic volume index (LVEDVi, 62 vs 71 ml/m², p= 0.02) in the Barlow group, despite similar ejection fractions and much less MR in the Barlow group. This resulted in a significantly higher RV/LVEDV ratio in the non-Barlow group compared to the Barlow group (42% vs 23%, p = 0.001). Similarly, the LA volume/LVEDV ratio was significantly lower in the Barlow cohort (63 vs 79%, p= 0.026). There were no significant differences in aortic dimensions between groups.

Conclusions

We describe for the first time that compared to non-Barlow (mostly FED), patients with MVP due to typical Barlow disease have larger ventricular dimensions and volumes, which are disproportionate to the degree of MR. We therefore hypothesize that the connective tissue alterations in these patients may also involve the myocardium resulting in LV dilation independent of MR. Further investigation and clinical implications of these findings is mandatory.

6119Correction of transcatheter aortic valve replacement induced left bundle branch block by His bundle pacing

Background

Left bundle branch block (LBBB) occurs frequently after transcatheter aortic valve replacement (TAVR) and is associated with increased risk of permanent pacemaker implantation, heart failure hospitalization and sudden cardiac death. This pilot study explored the feasibility of TAVR-induced LBBB correction with His bundle pacing (HBP).

Methods

Patients with TAVR -induced LBBB and postoperative need for permanent pacemaker implant were planned for electrophysiology study and HBP. Patients with persistent high degree AV-block were excluded. HBP was performed using the Select Secure pacing lead, delivered through a fixed curve or a deflectable sheath. Successful HBP was defined as correction of LBBB by selective or non-selective HBP with LBBB correction thresholds less than 3.5V at 1.0ms at implant.

Results

The study enrolled 6 patients (mean age 85±2.5 years, 50% male). Mean QRS duration was 152±10ms, PR-interval 212±12ms AH-interval 166±16ms and HV-interval 62±12ms. Successful HBP was achieved in 5/6 (83%) patients. Mean QRS duration decreased from 153±11ms to 88±14ms (p=0.002). At implantation, mean threshold for LBBB correction was 1.6±1.0V (unipolar) and 2.2±1.3V (bipolar) at 1.0ms. Periprocedural, two complete AV-blocks occurred, both spontaneously resolved by the end of the procedure. Thresholds remained stable at 1 month follow up: 1.8±1.0V (unipolar) and 2.3±1.5V (bipolar) at 1.0ms.

Figure 1

Conclusion

Permanent His bundle pacing can safely correct TAVR-induced LBBB in the majority of patients. Further studies are needed to assess potential benefits of His bundle pacing over conventional right ventricular pacing in this population.

P3372Prediction of outcome in functional mitral regurgitation using the average pixel intensity method

Background

Functional mitral regurgitation (FMR) is a frequent finding in patients with systolic heart failure. However, the echocardiographic grading of MR is challenging and different severity cut-offs are recommended by international guidelines. We developed and validated a novel echocardiographic parameter to grade MR, the average pixel intensity (API) method, based on pixel intensity analysis of the continuous wave Doppler signal.

Purpose

In this study, we assessed the long-term predictive value of the API method on clinical endpoints in FMR.

Methods

Transthoracic echocardiography was performed in consecutive heart failure patients with reduced EF (HF-REF) (n=221). MR was assessed using the API method, vena contracta width (VCW), effective regurgitant orifice area (PISA-EROA) and regurgitant volume (PISA-RV). The primary clinical events were major adverse cardiac events (MACE: cardiovascular mortality, mitral valve surgery, percutaneous mitral intervention or heart failure hospitalization).

Results

The API method was feasible in 97% of all FMR patients, which was significantly higher than parameters such as VCW, PISA-EROA and PISA-RV. 84 patients (37%) had one or more clinical events during the follow-up period (cardiovascular mortality (20%), mitral valve surgery (5%), percutaneous mitral intervention (5%), heart failure hospitalization (16%) or heart transplantation (2%)). Based on ROC curves, an API cut-off of 121 au was defined as “severe” MVP-MR with an overall better sensitivity and specificity than current guideline-recommended parameters. On multivariate analysis, MR graded with API was independently predictive for clinical events, whereas PISA-based methods were not independent. In addition, pulmonary pressures and NYHA class were powerful independent predictors of clinical outcome in FMR on multivariate analysis.

Conclusions

The API method better predicts clinical events and outcome in FMR compared to established grading methods. Therefore, the API method may be considered for grading FMR severity in clinical practice.

The urgent need for a harmonized severity scoring system for acute allergic reactions

The accurate assessment and communication of the severity of acute allergic reactions are important to patients, clinicians, researchers, the food industry, and public health and regulatory authorities. Severity has different meanings to different stakeholders with patients and clinicians rating the significance of particular symptoms very differently. Many severity scoring systems have been generated, most focusing on the severity of reactions following exposure to a limited group of allergens. They are heterogeneous in format, none has used an accepted developmental approach, and none has been validated. Their wide range of outcome formats has led to difficulties with interpretation and application. Therefore, there is a persisting need for an appropriately developed and validated severity scoring system for allergic reactions that work across the range of allergenic triggers and address the needs of different stakeholder groups. We propose a novel approach to develop and then validate a harmonized scoring system for acute allergic reactions, based on a data-driven method that is informed by clinical and patient experience and other stakeholders' perspectives. We envisage two formats: (i) a numerical score giving a continuum from mild to severe reactions that are clinically meaningful and are useful for allergy healthcare professionals and researchers, and (ii) a three-grade-based ordinal format that is simple enough to be used and understood by other professionals and patients. Testing of reliability and validity of the new approach in a range of settings and populations will allow eventual implementation of a standardized scoring system in clinical studies and routine practice.

EAACI Guidelines on Allergen Immunotherapy: Allergic rhinoconjunctivitis

Allergic rhinoconjunctivitis (AR) is an allergic disorder of the nose and eyes affecting about a fifth of the general population. Symptoms of AR can be controlled with allergen avoidance measures and pharmacotherapy. However, many patients continue to have ongoing symptoms and an impaired quality of life; pharmacotherapy may also induce some side-effects. Allergen immunotherapy (AIT) represents the only currently available treatment that targets the underlying pathophysiology, and it may have a disease-modifying effect. Either the subcutaneous (SCIT) or sublingual (SLIT) routes may be used. This Guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on AIT for AR and is part of the EAACI presidential project "EAACI Guidelines on Allergen Immunotherapy." It aims to provide evidence-based clinical recommendations and has been informed by a formal systematic review and meta-analysis. Its generation has followed the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included involvement of the full range of stakeholders. In general, broad evidence for the clinical efficacy of AIT for AR exists but a product-specific evaluation of evidence is recommended. In general, SCIT and SLIT are recommended for both seasonal and perennial AR for its short-term benefit. The strongest evidence for long-term benefit is documented for grass AIT (especially for the grass tablets) where long-term benefit is seen. To achieve long-term efficacy, it is recommended that a minimum of 3 years of therapy is used. Many gaps in the evidence base exist, particularly around long-term benefit and use in children.

Allergen immunotherapy for allergic rhinoconjunctivitis: A systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing Guidelines on Allergen Immunotherapy (AIT) for Allergic Rhinoconjunctivitis. To inform the development of clinical recommendations, we undertook a systematic review to assess the effectiveness, cost-effectiveness, and safety of AIT in the management of allergic rhinoconjunctivitis.

METHODS

We searched nine international biomedical databases for published, in-progress, and unpublished evidence. Studies were independently screened by two reviewers against predefined eligibility criteria and critically appraised using established instruments. Our primary outcomes of interest were symptom, medication, and combined symptom and medication scores. Secondary outcomes of interest included cost-effectiveness and safety. Data were descriptively summarized and then quantitatively synthesized using random-effects meta-analyses.

RESULTS

We identified 5960 studies of which 160 studies satisfied our eligibility criteria. There was a substantial body of evidence demonstrating significant reductions in standardized mean differences (SMD) of symptom (SMD -0.53, 95% CI -0.63, -0.42), medication (SMD -0.37, 95% CI -0.49, -0.26), and combined symptom and medication (SMD -0.49, 95% CI -0.69, -0.30) scores while on treatment that were robust to prespecified sensitivity analyses. There was in comparison a more modest body of evidence on effectiveness post-discontinuation of AIT, suggesting a benefit in relation to symptom scores.

CONCLUSIONS

AIT is effective in improving symptom, medication, and combined symptom and medication scores in patients with allergic rhinoconjunctivitis while on treatment, and there is some evidence suggesting that these benefits are maintained in relation to symptom scores after discontinuation of therapy.

Allergen immunotherapy for IgE-mediated food allergy: a systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is developing Guidelines for Allergen Immunotherapy (AIT) for IgE-mediated Food Allergy. To inform the development of clinical recommendations, we sought to critically assess evidence on the effectiveness, safety and cost-effectiveness of AIT in the management of food allergy.

METHODS

We undertook a systematic review and meta-analysis that involved searching nine international electronic databases for randomized controlled trials (RCTs) and nonrandomized studies (NRS). Eligible studies were independently assessed by two reviewers against predefined eligibility criteria. The quality of studies was assessed using the Cochrane Risk of Bias tool for RCTs and the Cochrane ACROBAT-NRS tool for quasi-RCTs. Random-effects meta-analyses were undertaken, with planned subgroup and sensitivity analyses.

RESULTS

We identified 1814 potentially relevant papers from which we selected 31 eligible studies, comprising of 25 RCTs and six NRS, studying a total of 1259 patients. Twenty-five trials evaluated oral immunotherapy (OIT), five studies investigated sublingual immunotherapy, and one study evaluated epicutaneous immunotherapy. The majority of these studies were in children. Twenty-seven studies assessed desensitization, and eight studies investigated sustained unresponsiveness postdiscontinuation of AIT. Meta-analyses demonstrated a substantial benefit in terms of desensitization (risk ratio (RR) = 0.16, 95% CI 0.10, 0.26) and suggested, but did not confirm sustained unresponsiveness (RR = 0.29, 95% CI 0.08, 1.13). Only one study reported on disease-specific quality of life (QoL), which reported no comparative results between OIT and control group. Meta-analyses revealed that the risk of experiencing a systemic adverse reaction was higher in those receiving AIT, with a more marked increase in the risk of local adverse reactions. Sensitivity analysis excluding those studies judged to be at high risk of bias demonstrated the robustness of summary estimates of effectiveness and safety of AIT for food allergy. None of the studies reported data on health economic analyses.

CONCLUSIONS

AIT may be effective in raising the threshold of reactivity to a range of foods in children with IgE-mediated food allergy whilst receiving (i.e. desensitization) and post-discontinuation of AIT. It is, however, associated with a modest increased risk in serious systemic adverse reactions and a substantial increase in minor local adverse reactions. More data are needed in relation to adults, long term effects, the impact on QoL and the cost-effectiveness of AIT.

Anaphylaxis: guidelines from the European Academy of Allergy and Clinical Immunology

Anaphylaxis is a clinical emergency, and all healthcare professionals should be familiar with its recognition and acute and ongoing management. These guidelines have been prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Taskforce on Anaphylaxis. They aim to provide evidence-based recommendations for the recognition, risk factor assessment, and the management of patients who are at risk of, are experiencing, or have experienced anaphylaxis. While the primary audience is allergists, these guidelines are also relevant to all other healthcare professionals. The development of these guidelines has been underpinned by two systematic reviews of the literature, both on the epidemiology and on clinical management of anaphylaxis. Anaphylaxis is a potentially life-threatening condition whose clinical diagnosis is based on recognition of a constellation of presenting features. First-line treatment for anaphylaxis is intramuscular adrenaline. Useful second-line interventions may include removing the trigger where possible, calling for help, correct positioning of the patient, high-flow oxygen, intravenous fluids, inhaled short-acting bronchodilators, and nebulized adrenaline. Discharge arrangements should involve an assessment of the risk of further reactions, a management plan with an anaphylaxis emergency action plan, and, where appropriate, prescribing an adrenaline auto-injector. If an adrenaline auto-injector is prescribed, education on when and how to use the device should be provided. Specialist follow-up is essential to investigate possible triggers, to perform a comprehensive risk assessment, and to prevent future episodes by developing personalized risk reduction strategies including, where possible, commencing allergen immunotherapy. Training for the patient and all caregivers is essential. There are still many gaps in the evidence base for anaphylaxis.

Paediatric rhinitis: position paper of the European Academy of Allergy and Clinical Immunology

Rhinitis is a common problem in childhood and adolescence and impacts negatively on physical, social and psychological well-being. This position paper, prepared by the European Academy of Allergy and Clinical Immunology Taskforce on Rhinitis in Children, aims to provide evidence-based recommendations for the diagnosis and therapy of paediatric rhinitis. Rhinitis is characterized by at least two nasal symptoms: rhinorrhoea, blockage, sneezing or itching. It is classified as allergic rhinitis, infectious rhinitis and nonallergic, noninfectious rhinitis. Similar symptoms may occur with other conditions such as adenoidal hypertrophy, septal deviation and nasal polyps. Examination by anterior rhinoscopy and allergy tests may help to substantiate a diagnosis of allergic rhinitis. Avoidance of relevant allergens may be helpful for allergic rhinitis (AR). Oral and intranasal antihistamines and nasal corticosteroids are both appropriate for first-line AR treatment although the latter are more effective. Once-daily forms of corticosteroids are preferred given their improved safety profile. Potentially useful add-on therapies for AR include oral leukotriene receptor antagonists, short bursts of a nasal decongestant, saline douches and nasal anticholinergics. Allergen-specific immunotherapy is helpful in IgE-mediated AR and may prevent the progression of allergic disease. There are still a number of areas that need to be clarified in the management of rhinitis in children and adolescents.

Towards a European registry of severe allergic reactions: current status of national registries and future needs

The incidence of severe allergic reactions is largely unknown and information about triggering allergens, aggravating factors, demography of patients and medical care is lacking. A European wide registry could provide a powerful tool to improve the management of severe allergic reactions from both a medical and a public health perspective. Analysis of existing registries regarding the type and quality of data being collected was used to develop a plan for a pan-European registry, including the type of system to be used and the range of data to be entered. Surveillance will provide evidence for the efficacy of risk management measures and may identify the emergence of new allergenic foods, and aid monitoring of novel foods, ingredients and technologies. Patients need a clear indication of factors that may increase their risk of having an adverse reaction, which such a registry can help compile. Based on the collected data, food businesses will be able to develop educational programmes for allergen risk assessment and allergen risk communication. Finally, and most importantly preventive measures can be developed and government agencies receive population based data which may be relevant for legislative purposes.

Thresholds for food allergens and their value to different stakeholders

Thresholds constitute a critical piece of information in assessing the risk from allergenic foods at both the individual and population levels. Knowledge of the minimum dose that can elicit a reaction is of great interest to all food allergy stakeholders. For allergic individuals and health professionals, individual threshold data can inform allergy management. Population thresholds can help both the food industry and regulatory authorities assess the public health risk and design appropriate food safety objectives to guide risk management. Considerable experience has been gained with the double-blind placebo-controlled food challenge (DBPCFC), but only recently has the technique been adapted to provide data on thresholds. Available data thus vary greatly in quality, with relatively few studies providing the best quality individual data, using the low-dose DBPCFC. Such high quality individual data also form the foundation for population thresholds, but these also require, in addition to an adequate sample size, a good characterization of the tested population in relation to the whole allergic population. Determination of thresholds at both an individual level and at a population level is influenced by many factors. This review describes a low-dose challenge protocol developed as part of the European Community-funded Integrated Project Europrevall, and strongly recommends its wider use so that data are generated that can readily increase the power of existing studies.

Stem Cells for the Heart, Are We There Yet?

Although several repair mechanisms have been described in the human heart, all fall too short to prevent clinical heart disease in most acute or chronic pathological cardiac conditions. Moreover, despite many breakthroughs in cardiovascular medicine, the complications of a myocardial infarction such as chronic heart failure remains a serious worldwide problem. Bone marrow stem cells could provide for a promising strategy to restore myocardial infarctions and prevent postinfarct congestive heart failure, because there is growing body of evidence that bone marrow stem cells, such as mesenchymal stem cells, can generate new cardiomyocytes in animals and humans. In this review, we will discuss important issues on stem cell therapy for cardiac regeneration after myocardial infarction, which might be of paramount importance when considering future human trials.

Dynamic gadolinium-enhanced MR imaging of pancreatic VIPoma in a patient with Verner-Morrison syndrome

We describe a rare case of a pancreatic VIPoma diagnosed in a patient presenting with watery diarrhea, hypokalemia, and achlorhydria, the so-called WDHA or Verner-Morrison syndrome. Emphasis is placed on the dynamic gadolinium-enhanced MR profile of the tumor, characteristics which have not been illustrated previously, to the best of our knowledge.

Canadian aid program in Angola faces huge problems

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Prospective study on the incidence of complications of right heart catheterization

Indications for hemodynamic assessment by right heart catheterization include shock, pulmonary edema, severe trauma and sepsis. The introduction of the catheter and the location of the tip in the pulmonary artery, however, can cause severe complications. In the present study the incidence of complications was observed in 93 consecutive right heart catheterizations in critically ill patients with no evidence of recent myocardial infarction. The low incidence of complications during introduction and with the catheter tip located in the pulmonary artery justifies right heart catheterization in patients with hemodynamic and/or respiratory instability treated in an intensive care unit.