Title：Early assessment of ventricular synchronization and function after left bundle-branch-area pacing with right bundle-branch block

Aim To evaluate ventricular synchronization and function in patients with right bundle-branch block after left bundle-branch-area pacing (LBBAP) by echocardiography. Methods Forty patients who successfully received LBBAP were selected and divided into the right bundle-branch block group (RBBB group) and the non-RBBB group by pre-operation ECG. Echocardiography and follow-up were performed 1 month after operation. Interventricular synchronization was evaluated by tissue Doppler (TDI), tissue mitral annular displacement (TMAD), and interventricular mechanical delay (IVMD). The ventricular longitudinal strain and the standard deviation of peak time of longitudinal strain were analyzed by two-dimensional speckle tracking imaging (2D-STI) to evaluate intraventricular synchronization and ventricular function. Results (1) The deviation of systolic time to the peak of the tricuspid and mitral valves, namely ΔPTTV-MV measured by TMAD and ΔTsTV-MV measured by TDI, were statistically different between the two groups (P < 0.05). (2) Compared with the non-RBBB group, there were no statistically significant differences in longitudinal strain (LS), peak strain time, standard deviation of peak strain time (SDt), and global longitudinal strain (GLS) in the right and left ventricle in the RBBB group (P > 0.05). Conclusion Echocardiography technology including 2D-STI, TDI, and TMAD can effectively analyze interventricular synchronization, intraventricular synchronization, and ventricular function. Although the movement of the right ventricular myocardium in the RBBB group treatment was slightly later than that of the left ventricular myocardium after LBBAP, LBBAP is still an effective pacing therapy for RBBB patients with pacing indication.

787 Ablation of the ventricular ectopic foci: a therapeutic option for dilated cardiomyopathy due to arrhythmic MVP

Aims A subset of patients with mitral valve prolapse (MVP) are affected by a still not well understood condition characterized by frequent ventricular arrhythmias (mostly originating from papillary muscles) and sudden cardiac death (SCD). It is called MVP malignant syndrome (MVP MS). In these patients, the high arrhythmic burden may lead to left ventricular (LV) dyssynchrony and dysfunction, determining a tachycardia-induced cardiomyopathy (TIC). Reduction in arrhythmic burden determines LV recovery and ejection fraction improvement and interrupts LV progressive dilatation. Methods and reports We report the case of a 52-year-old woman with MVP and family history of both MVP and SCD who was referred to our department for symptomatic extrasystoles and dyspnoea during exercise. Palpitations begun 11 years before: in that occasion she performed a 3-lead-ECG-Holter monitoring which documented 3457 ventricular extrasystoles. Transthoracic echocardiography (TTE) showed normal LV dimension and function and a myxomatous mitral valve with prolapse of both leaflets. At that time beta-blocker therapy was introduced, but soon suspended because of patient’s clinical intolerance (bradycardia and hypotension). Since then she was lost at follow-up for years, until symptoms worsened. When she came to our attention, TTE showed dilated and hypokinetic LV (ejection fraction was 38%, S2 wave at TDI was 6.4 cm/s and global longitudinal strain value was −13%). CMR was performed and confirmed TTE findings. Mitral-annulus disjunction was described in anterior, lateral, and posterior wall and late gadolinium enhancement analyses showed subendocardial fibrosis in correspondence of the posterior papillary muscle (PM) and in the mid-inferior wall. Holter monitoring enlightened a high arrhythmic burden with 24 065 premature ventricular complexes (PVCs) of two morphologies (right bundle branch block-like and −120° axis and right bundle branch block-like and −75° axis). During stress test, PVCs increased as the heart rate increased, resulting in bigeminism at peak exercise. Considering all these features, we hypothesized a case of MVP MS in which the high ventricular arrhythmic burden resulted in TIC. Any available pharmacological attempt to reduce arrhythmias failed. Transcatheter (TC) ablation of PVCs was then proposed. Electrophysiological study identified the inner part of the posterior papillary muscle implantation region and the antero-lateral basal wall as PVCs sites of origin. Radiofrequency ablation was performed in both sites. After the procedure, despite an incomplete suppression of the posterior PM focus, 12-lead 24-h Holter monitoring and TTE performed during the hospitalization showed a consistent arrhythmic burden reduction and LV function improvement. At 6 months from the procedure, symptoms improved and Holter monitoring showed 7515 PVCs with a 54% arrhythmic burden reduction compared with the presentation. TE showed lower LV end-diastolic volume and an increase in ejection fraction up to 47%; global longitudinal strain was −17% and TDI showed a S2 wave on lateral wall of 11 cm/s, confirming left ventricle improvement after the arrhythmic burden reduction. Conclusions Complete suppression of PMs PVCs with TC ablation is difficult to obtain, especially when the focus is in the inner part of the PM and TC ablation of ventricular arrhythmias in MVP patients has not yet demonstrated his efficacy in reducing SCD. Nevertheless, it should be taken into consideration to obtain at least PVCs reduction in patients with high arrhythmic burden leading to TIC.

Right bundle branch block and male sex may help predict appropriate ICD therapies in patients with non-ischemic dilated cardiomyopathy and a prophylactic implantable cardioverter defibrillator

Background Previous studies have shown that prophylactic implantable cardioverter-defibrillators (ICD) in patients with symptomatic severe systolic dysfunction reduce all-cause mortality. However, their benefit in patients with severe systolic dysfunction of non-ischemic origin is not so clear, and is currently under debate. Methods/Aim We retrospectively reviewed all consecutive patients with nonischemic dilated cardiomyopathy (NICM) who underwent prophylactic ICD implantation between 2008 and 2020 in two tertiary centers. Our main goal was to identify predictors of appropriate ICD therapies (ATP and/or shocks) in this cohort of patients. Results A total of 224 patients were included, median age 62.7 years, 73.7% men. During a median follow-up of 51 months, 61 patients (27.2%) required appropriate ICD intervention, 7 patients (3.1%) presented inappropriate shocks and 11 (4.9%) had device infection. Patients that received appropriate ICD therapies, as compared to those who did not, were more frequently men (86.9% vs 68.7%, p=0.006) and were significantly younger (median age 58.7 years, IQR 53.0–64.8 vs 63.7, IQR 57.0–69.8; p=0.02). Left ventricular end diastolic volume (LV-EDV) and left ventricular end systolic volume (LV-ESV) were both significantly higher in this subgroup of patients (median LVEDV 100 ml/m2 vs 86, p=0.0106; median LVESV 72.2 ml/m2 vs 60.9, p=0.0467). A trend towards lower LVEF was also noted, but it did not reach statistical significance (26% vs 29%, p=0.077). Regarding ECG previous to implant, patients that required ICD intervention presented more frequently complete right bundle branch block (RBBB) (14.8% vs 4.3%, p=0.007). On the other hand, left bundle branch block (LBBB) was more frequent in those patients who did not receive ICD intervention during follow-up (47.2% vs 26.2%, p=0.005). Table 1 summarizes baseline characteristics and results. In a multivariate Cox regression analysis, RBBB (HR 3.9, CI 95% 1.9–8.0, p&lt;0.001) and male sex (HR 2.38, CI 95% 1.07–5.28, p=0.034) were identified as independent predictors of appropriate ICD therapies (Figure 2). Conclusion RBBB and male sex may help identify patients with NICM at high-risk of ventricular arrhythmias requiring ICD intervention. FUNDunding Acknowledgement Type of funding sources: None. Baseline characteristics and results Kaplan-Meier curves