SPC365

Morphologic Subtypes of LBBB and Their Prognostic Value in Cardiac Resynchronization Therapy

Session: Sessão de Posters 53 - Otimização de CRT em 2026
Speaker: Joana Simões de Azevedo Massa Pereira

Congress: CPC 2026
Topic: C. Arrhythmias and Device Therapy
Theme: 09. Device Therapy
Subtheme: 09.3 Cardiac Resynchronization Therapy
Session Type: Posters Eletrónicos
FP Number: ---
Authors: Joana Massa Pereira; Sofia Andraz; Lucas Hamann; Joana Guerreiro Pereira; Daniela Carvalho; Miguel Espírito Santo; Raquel Fernandes; João Sousa Bispo; Pedro Azevedo; Rui Candeias; Hugo Alex Costa; Jorge Mimoso

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">Introduction: </span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">Differences in LBBB morphology&mdash;true complete LBBB (tcLBBB), due to conduction system degeneration, and LBBB-like pattern (lpLBBB), reflecting myocardial pathology&mdash;are common and may influence CRT response. However, their association with CRT outcomes is not fully established.</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">Objective: </span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">To assess the association between LBBB morphology/pattern and clinical outcomes in CRT patients. </span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">Methods: </span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">A retrospective analysis (2020&ndash;2023) involved 95 patients who underwent CRT implantation. Data collected included demographics, risk factors and echocardiographic/electrocardiographic parameters. Patients were classified as lpLBBB or tcLBBB using European Society of Cardiology criteria. The primary outcome was the composite of all-cause death and/or heart failure (HF) hospitalization. Predictors were identified through multivariate logistic regression<strong>. </strong></span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">Results: </span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">The final cohort included 88 patients (58% lpLBBB; 42% tcLBBB)</span></span> <span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">mean age 69.5&plusmn;10.4 years, 77.3% male. Baseline QRS duration was 166&plusmn;24ms, with a wider QRS in tcLBBB (178&plusmn;21ms, p=0.006). Mean biventricular pacing was 95.9% with no differences between groups. QRS reduction &ge; 26ms (51.4%, p&lt;0.001), LBBB duration &gt; 150ms (98.8%, p=0.001), use of mineralocorticoids receptor antagonists drugs (81.1%, p=0.047), QRS variation (28.2&plusmn;20.5, p&lt;0.001) and greater improvement in LVEF (29.7% --&gt; 44.2%, p=0.001) and LVEDV (210ml --&gt; 159ml, p=0.006) were more frequent among tcLBBB. CRT super-response occurred in 23 patients (39.7%), significantly more frequent in tcLBBB (62.5%, p=0.003). The primary outcome occurred in 26 patients (29.5%) with no significant difference between groups (lpLBBB 33.3% vs tcLBBB 24.3%, p=0.361). However, all-cause mortality was lower in the tcLBBB group (16.2%, p=0.021). Super-response was not associated with improved clinical outcomes (20.8%, p=0.583). In multivariate analysis, predictors of the primary outcome included smoking (OR 11.54, p=0.033), while non-ischemic etiology (OR 0.003, p = 0.045) and tcLBBB morphology (OR 0.002, p = 0.043) were protective.</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">Conclusions: </span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Aptos&quot;,sans-serif">In this cohort, tcLBBB morphology prior to CRT implantation was associated with greater reverse remodeling&mdash;reflected by improvements in LVEF, LVEDV, and higher rates of super-response. However, these parameters were not associated with a lower risk of the composite outcome of death or HF hospitalization, although all-cause mortality alone was lower among patients with tcLBBB. Predictors of the primary outcome were tcLBBB and non-ischemic etiology (both protective) and smoking (risk factor) in a medium/long term follow-up. These findings suggested that although the presence of a tcLBBB is likely necessary for CRT response, it is unlikely to be sufficient to be linked to a better prognosis alone, and other variables should be considered like the presence of LV scar as well as the subtype of cardiomyopathy.&nbsp; </span></span></span></span></p>