SPC365

Do implantable loop recorders have a role in hypertrophic cardiomyopathy?

Session: SESSÃO DE POSTERS 55 - ARRITMOLOGIA: NOVOS DESAFIOS
Speaker: Margarida G. Figueiredo

Congress: CPC 2025
Topic: F. Valvular, Myocardial, Pericardial, Pulmonary, Congenital Heart Disease
Theme: 17. Myocardial Disease
Subtheme: 17.7 Myocardial Disease - Other
Session Type: Cartazes
FP Number: ---
Authors: Margarida G. Figueiredo; José Miguel Viegas; Isabel Cardoso; Pedro Brás; Guilherme Portugal; Ana Lousinha; Pedro Silva Cunha; Mário Oliveira; Sílvia Aguiar Rosa; Rui Ferreira

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong>Introduction </strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Implantable loop recorders (ILRs) are a minimally invasive tool for the diagnosis of arrhythmias that have been increasingly used for the detection of infrequent arrhythmias in patients (P) with cardiomyopathies, especially in the presence of high-risk markers. The role of ILR in improving the detection of significant arrhythmias that require a change in clinical management remains unexplored.</span></span></p>

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<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong>Purpose</strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Our purpose was to evaluate the diagnostic yield of ILR monitoring, regarding clinically relevant arrhythmias and subsequent management in P with cardiomyopathies receiving an ILR.</span></span></p>

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<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong>Methods</strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Prospective single-centre study in P with cardiomyopathies in &ldquo;grey zone&rdquo; for the risk of ventricular arrhythmias, who, for this reason, underwent an ILR implantation. The primary endpoint was a meaningful arrhythmic event leading to a change in clinical management.</span></span></p>

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<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong>Results</strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">45 P were included, 51% (23P) male, median age 62 (48 - 71) years. The underlying disease was hypertrophic cardiomyopathy (HCM) in 69% (31P), dilated and non-dilated left ventricle cardiomyopathy (DCM/NDLVC) in 26% (12P) and transthyretin amyloidosis (ATTR) in 4% (2P).</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">The most frequent risk markers were brief run of non-sustained ventricular tachycardia (VT) in 42%, unexplained syncope or pre-syncope in 36%, family history of premature sudden cardiac death (SCD) in a first-degree relative in 36%, and palpitations suspicious of arrhythmic origin in 18%. </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">58% of the P with DCM/NDLVC had LV ejection fraction &lt;50%, of which 8% had extensive late gadolinium enhancement (LGE). Regarding P with HCM, median HCM Risk-SCD score was 3.07 (2.68 &ndash; 3.76) %, with 16% having an estimated 5-year risk of SCD &ge;4%. Mean maximum wall thickness was 20&plusmn;4mm, left atrial diameter (LAD) 43&plusmn;7mm, 23% had obstructive HCM, LGE was present in 74% - with 52% of P with extensive LGE - and LV apical aneurysm in 3%. </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">During a mean follow-up of 19&plusmn;13 months, 44% of P had, at least, one ILR-guided diagnosis. ILR-guided diagnosis and therapies are described in Table 1 and 2, respectively. <em>De novo</em> atrial fibrillation (AF) was diagnosed in 24% of P and was the main detected event. Regarding devices, 20% of P received implantable cardioverter-defibrillators (ICD), one of which with subsequent appropriate shocks. The incidence of the primary endpoint was 36%.</span></span></p>

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<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong>Conclusion</strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">This study provides insight into the incremental value of ILRs in this group of P, not only for the diagnosis of ventricular arrhythmias, but also for detection of subclinical AF, which can lead to a different therapeutic management in this specific population. </span></span></p>