Left bundle branch block causes left atrial dyssynchrony: a result of atrio-ventricular mechanical interaction

Introduction Left bundle brach block (LBBB) leads to left ventricular (LV) mechanical dyssynchrony with septal flash and delayed lateral wall contractions. Since atrium and ventricle are anatomically connected, dyssynchronous LV contractions may be transmitted to the left atrium, thereby disturbing left (LA) function. Purpose To test the hypothesis that patients with LBBB have LA dyssynchrony induced by tethering to the dyssynchronous left ventricle. Methods Myocardial strain was measured by speckle-tracking echocardiography in 20 non-ischaemic heart failure patients with LBBB, before and 6 months after cardiac resynchronization therapy (CRT), and in 20 healthy controls. For the LA, dyssynchrony was measured as time delay between onset of the interatrial septum and the lateral wall, and for the LV, between onset septal flash and onset lateral wall contraction. White arrows in Figure indicate onset LA stretch. Results As shown in the Figure, patients with LBBB and HF had marked LA reservoir phase dyssynchrony. Before CRT time delay from onset LA septal stretch to onset lateral wall stretch was 125±71 ms (mean±SD), and decreased to 23±70 (p<0.0001) with CRT. In controls there was a small delay of 34±56 ms. The LA dyssynchrony correlated with LV dyssynchrony (r=0.50, p=0.033), supporting the hypothesis that LA dyssynchrony in LBBB represents mechanical interaction due to tethering between the respective walls. Conclusions Patients with LBBB had marked LA reservoir phase dyssynchrony, which was abolished with CRT. The LA dyssynchrony was attributed to direct LV-LA mechanical interaction. The observed LA resynchronization by CRT represent an additional benefit of CRT in patients with heart failure. FUNDunding Acknowledgement Type of funding sources: None. Left atrial and ventricular dyssynchrony

Presence of contractile impairment appears crucial for structural remodeling in idiopathic left bundle-branch block

Background To differentiate effects of ventricular asynchrony from an underlying hypocontractile cardiomyopathy this study aimed to enhance the understanding of functional impairment and structural remodeling in idiopathic left bundle-branch block (LBBB). We hypothesize, that functional asynchrony with septal flash volume effects alone might not entirely explain the degree of functional impairment. Hence, we suggest the presence of a superimposed contractile cardiomyopathy. Methods In this retrospective study, 53 patients with idiopathic LBBB were identified and matched to controls with and without cardiovascular risk factors. Cardiovascular magnetic resonance (CMR) was used to evaluate cardiac function, volumes and myocardial fibrosis using native T1 mapping and late gadolinium enhancement (LGE). Septal flash volume was assessed by CMR volumetric measurements and allowed to stratify patients with systolic dysfunction solely due to isolated ventricular asynchrony or superimposed contractile impairment. Results Reduced systolic LV-function, increased LV-volumes and septal myocardial fibrosis were found in patients with idiopathic LBBB compared to healthy controls. LV-volumes increased and systolic LV-function declined with prolonged QRS duration. Fibrosis was typically located at the right ventricular insertion points. Subgroups with superimposed contractile impairment appeared with pronounced LV dilation and increased fibrotic remodeling compared to individuals with isolated ventricular asynchrony. Conclusions The presence of superimposed contractile impairment in idiopathic LBBB is crucial to identify patients with enhanced structural remodeling. This finding suggests an underlying cardiomyopathy. Future studies are needed to assess a possible prognostic impact of this entity and the development of heart failure. Trial registration: This study was retrospectively registered.

Septal flash as a predictor of cardiac resynchronization therapy response: A systematic review and meta-analysis

Background: Cardiac resynchronization therapy (CRT) in heart failure patients has been shown to improve patient outcomes in some but not all patients. A few studies have identified that septal flash on imaging is associated with response to CRT but there has yet to be systematic review to evaluate consistency of the finding across the literature. Methods: A search of MEDLINE and EMBASE was conducted to identify studies which evaluate septal flash and its association with CRT response. Studies that met the inclusion criteria were statistically pooled with random-effects meta-analysis and heterogeneity was assessed using the I statistic. Results: A total of nine studies were included with 2,307 participants (mean age 76 years, 67% male). Septal flash on imaging before CRT implantation was seen in 53% of patients and the proportion of CRT responders from the included studies varied from 52% to 77%. In patients who were CRT responders, septal flash was seen in 40% of patients compared to 10% in those deemed to be CRT non-responders. Meta-analysis of the eight studies suggests that the presence of septal flash at pre-implant was associated with an increased likelihood of CRT response (RR 2.55 95%CI 2.04-3.19, p<0.001, I2=51%). Septal flash was also reported to be associated with left ventricular reverse remodelling but the association with survival and symptomatic improvement was less clear. Conclusions: Septal flash is a well-defined and distinctive contraction pattern which is consistently associated with CRT response and should be evaluated when assessing for appropriateness of CRT device.

Πρόβλεψη ανταπόκρισης στη θεραπεία καρδιακού επανασυγχρονισμού με υπερηχογραφικά κριτήρια σε ασθενείς με καρδιακή ανεπάρκεια

Ιστορικό: Η μη ανταπόκριση στη θεραπεία καρδιακού επανασυγχρονισμού (ΘΚΕ) παραμένει ένα ζήτημα, παρά τη βελτίωση των κριτηρίων επιλογής. Σκοπός της παρούσας μελέτης ήταν η διερεύνηση του ρόλου της ηχωκαρδιογραφίας για την επιλογή ασθενών που θα έχουν ανταπόκριση ή καθυστερημένη ανταπόκριση σε ΘΚΕ, χρησιμοποιώντας παραμέτρους δυσυγχρονισμού και εφαρμογές δυναμικής ηχωκαρδιογραφίας. Μέθοδοι: 106 ασθενείς με συμπτωματική καρδιακή ανεπάρκεια εξετάστηκαν πριν, 6 μήνες μετά και 2 έως 4 χρόνια μετά την εφαρμογή του ΘΚΕ. Η ινότροπη συστολική εφεδρεία (ΙΣΕ) και η βιωσιμότητα του οπισθίου τοιχώματος της αριστερής κοιλίας (ΟΤΑΚ) μελετήθηκαν με δυναμική ηχωκαρδιογραφία. Ο δυσυγχρονισμός εκτιμήθηκε με: 1) Καθυστέρηση κίνησης μεταξύ διαφραγματικού και οπισθίου τοιχώματος (Septal-to-posterior wall motion delay - SPWMD με m-mode 2) Καθυστέρηση μεταξύ διαφραγματικού και πλαγίου τοιχώματος (Septal to lateral wall delay -SLD) από το TDI 3) Διακοιλιακή μηχανική καθυστέρηση (Interventricular mechanical delay -IVMD) 4) Διαφορά στο χρόνο μέχρι τη μέγιστη κυκλοτερή παραμόρφωση (Difference in time to peak circumferential strain -TmaxCS) με ηχωκαρδιογραφία ιχνηλάτησης σημείων 5) «Ταλάντωση κορυφής» (Apical rocking - ApR) και «αναλαμπή μεσοκοιλιακού διαφράγματος» (septal flash - SF) με οπτική εκτίμηση. Αποτελέσματα: Σε έξι μήνες υπήρχαν 54 άτομα που ανταποκρίθηκαν, και δώδεκα επιπλέον άτομα είχαν καθυστερημένη ανταπόκριση. Το TmaxCS είχε τη μεγαλύτερη προγνωστική αξία, με μια περιοχή κάτω από την καμπύλη (AUC) 0,835, ακολουθούμενο από την συνδυασμένη παρουσία ΙΣΕ και βιωσιμότητας του ΟΤΑΚ (AUC 0,799), το m-mode (AUC = 0,775) και την παρουσία ApR ή/και SF (AUC = 0.772). Η προγνωστική ικανότητα του ApR και του ICR αυξάνεται εάν συμπεριληφθούν και τα άτομα με καθυστερημένη ανταπόκριση. Η απόδοση των παραμέτρων δυσυγχρονισμού ενισχύεται, σε ασθενείς με ΙΣΕ και βιωσιμότητα του ΟΤΑΚ. Συμπέρασμα: Η δυναμική ηχωκαρδιογραφία και οι παράμετροι δυσυγχρονισμού είναι απλοί και αξιόπιστοι δείκτες πρόβλεψης της απόκρισης στη ΘΚΕ, εντός 6μήνου ή καθυστερημένα. Μια σταδιακή προσέγγιση με μια αρχική εκτίμηση ΙΣΕ και βιωσιμότητας και, εάν αυτή είναι θετική, μια περαιτέρω ανάλυση δυσυγχρονισμού, θα μπορούσε να βοηθήσει στην λήψη αποφάσεων σε αμφιλεγόμενες κλινικά περιπτώσεις.

Relationship of septal flash with electromechanical dyssynchrony and super-response to cardiac resynchronization therapy

Objectives - to identify a relationship of septal flash (SF) with a super-response to cardiac resynchronization therapy (CRT), apical rocking (AR) and signs of left bundle brunch block (LBBB) in patients with congestive heart failure (CHF). Material and methods. The study included 38 patients (92.1% men; mean age 54.3±9.4 years) with II-IV NYHA functional class CHF. Left bundle brunch block (LBBB) was diagnosed according to 3 criteria: American Heart Association (AHA) 2009, European Society of Cardiology (ESC) 2013, Strauss. Septal flash (SF, mechanical anomaly of interventricular septum (IVS) movement) is determined according to speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI). The patients were divided into two groups: with SF (I group, n=8) and without SF (II group, n=30). Mean follow-up was 34.5 [13.8;55.3]. Results. At baseline the groups did not differ in main clinical characteristics including QRS. The left ventricular (LV) ejection fraction (EF) was higher in group I (33.1%±1.7 and 30.0%±4.0; p=0.044). Basal segment of IVS longitudinal strain (LS) delay by STE (258.0 [144.0;294.0] ms vs 323.5 [273.3;385.0] ms; р=0.024) and LS delay by TDI (176.0 [146.8;287.3] ms vs 415.5 [315.8;493.5] ms; р30%); 53.1% of patients in group II were super responders (р

P539Comparative analysis of patients with cardiac resynchronization therapy depending on septal flash

Background Mechanical dyssynchrony (MD) and superresponse (SR) to cardiac resynchronisation therapy (CRT) relationship is still debated. Aim To assess clinical and morpho-functional features of the heart in patients with congestive heart failure (CHF) after cardiac resynchronization therapy (CRT) depending on septal flash (SF). Materials and methods The study enrolled 60 patients (92.0% men, 8.0% women; mean age 54.5 ± 10.4 years; 70.0% had left bundle branch block (LBBB) with II-IV NYHA functional class CHF. SF (mechanical anomaly of interventricular septum (IVS) movement) is determined according to speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI). Patients were divided into two groups: with SF (I group, n = 10) and without SF (II group, n = 50). Results At baseline the groups did not differ in main clinical characteristics including QRS width and LBBB. Mechanical interventricular delay was higher in group I (65.5 ms [53.5;95.5] vs 31.0 ms [15.0;64.5]; р=0.026). Basal segment of IVS longitudinal strain (LS) delay by STE (257.5 ms [156.3;293.8] vs 323.5 ms [262.5;377.8]; р=0.024) and LS delay by TDI (204.0 ms [170.8;260.3] vs 434.0 ms [370.0;489.0]; р&lt;0.001) were significantly lower in group with SF. According to logistic regression a combination of LS apical segment of IVS by STE (HR 0.607; 95% Cl 0.369 – 0.989; р=0,048) and LS delay basal segment of IVS by TDI (HR 0.969; 95% Cl 0.0945 – 0.993; р=0.011) had a relationship with SF. According to ROC analysis sensitivity and specificity of this model in SF definition in patients with CRT were 87.5% and 86.5% (AUC = 0.939; p &lt; 0.01). Mean changes in LV ESV (52.0 ml [32.5;72.8] vs 19,0 ml [1.3;40.0]; р=0.002) and LV ejection fraction (EF) (13.0% [5.5;18.8] vs 4.0% [2.0;9.0]; р=0.002) were significantly higher in patients with SF. All patients in group I had a super-response to CRT (ESV LV decrease ≥30%); 42.0% patients in group II were superresponders (р&lt;0.001). Conclusion SF could be determined by STE and TDI. SF is associated with severe mechanical interventricular dyssynchrony and superresponse to CRT. Patients with SF have significantly better LV EF dynamics after CRT. Abstract Figure. Septal Flash in patient with SR to CRT

P1163Correction of septal flash excursion with his bundle pacing

Funding Acknowledgements Grant from the Catalan Society of Cardiology Background His bundle pacing (HBP) directly stimulates the conduction system and could therefore correct asynchrony and evolve as a more physiological pacing approach. Septal flash (SF) is a fast contraction and relaxation of the septum occurring during the isovolumetric contraction period. It is a specific marker of cardiac dyssynchrony. Purpose Evaluate whether HBP corrects SF in patients with an indication for CRT or RV pacing. Methods A cohort of 20 consecutive patients undergoing HBP at our center was analyzed. HBP indications were: Group A (n = 3): left bundle branch block (LBBB) and left ventricular (LV) dysfunction (LV ejection fraction [LVEF] &lt; 35%); Group B (n = 14): LV dysfunction (LVEF &lt; 50%) and atrio-ventricular block requiring permanent pacing; Group C (ablate&pace, n = 3): atrio-ventricular node ablation due to rapid atrial fibrillation. Patients in groups B and C had a RV backup lead implanted, in line with current recommendations. The presence of SF was analyzed in 2D-echocardiography at 15 days post-implant. SF excursion was quantified using M-mode in parasternal short and long axis views as the highest amplitude of the early inward motion. Baseline SF excursion was determined during intrinsic rhythm (group A) or RV pacing (groups B and C). For each patient, the pair of measurements (baseline, HBP) in the axis with the highest baseline SF was selected. Results Mean LVEFs were 21 ± 8%, 32 ± 6%, and 41 ± 18% for groups A, B and C, respectively. HBP shortened QRS duration by 42 ± 15 ms and 45 ± 23 ms in groups A (Baseline QRS - HBP QRS) and B + C (RV pacing QRS - HBP QRS), respectively. At baseline, all patients except 1 had SF (Fig. 1A). The mean SF excursion was 4.3 ± 1.9 mm, with SF excursion being larger in group A than in the RV-paced groups (6.3 ± 1.5 mm vs. 3.9 ± 1.8 mm for groups A and B + C, respectively, p = 0.04). HBP abolished SF in 3 patients (15%) and, on average, decreased SF excursion by 2.3 mm (95% CI 1.3-3.2), irrespective of pacing indication (Fig. 1B). The degree of SF excursion reduction after HBP significantly correlated with QRS shortening (r = 0.53, p = 0.024) (Fig 1C). Conclusions In conclusion, we show that HBP results in acute correction or decrease of SF, thereby improving LBBB- or RV-induced mechanical dyssynchrony. Abstract Figure. Septal Flash and His pacing