Corresponding Author
Key Words: cardiac magnetic resonance, cardiomyopathy, imaging, left ventricle
Left ventricular noncompaction is a rare and underdiagnosed cardiomyopathy that may lead to heart failure, arrhythmias, sudden cardiac death (SCD), conduction abnormalities, and thromboembolic events. Early diagnosis is crucial to prevent complications; however, accurately distinguishing physiological trabeculation from pathologic hypertrabeculation remains challenging. This diagnostic uncertainty can result in delayed or inappropriate management and may adversely affect disease course and outcomes.1
In this issue of JACC: Case Reports, the authors present the case of a young, asymptomatic patient in whom advanced conduction disease was detected incidentally. The baseline electrocardiography already demonstrated significant His-Purkinje system involvement, with right bundle branch block and left anterior fascicular block, an uncommon finding in young individuals. Given the patient's age and these abnormalities, secondary causes warranted careful exclusion. After completion of the diagnostic work-up, the only relevant finding was left ventricular hypertrabeculation.2
Although the genetic variants most frequently associated with left ventricular noncompaction typically involve sarcomeric proteins, including TTN and MYH7, variants in genes more commonly linked to channelopathies and conduction disease (such as SCN5A and HCN4) have also been reported. Genetic testing is highly relevant in these patients, as the identification of a pathogenic variant may predict progression of conduction system disease despite optimal medical therapy. The risk of SCD may be increased, underscoring the importance of early assessment for cardiac pacing and strategies aimed at sudden death prevention.3, 4, 5
Cardiac pacing in young patients (particularly those younger than 40 years) is not free from complications. The need for repeated generator replacements over time, and sometimes for system upgrades requiring implantation of new leads, exposes these patients to the cumulative procedural risks inherent to each subsequent intervention. For this reason, pacing therapy has traditionally been deferred whenever feasible in this population.
In recent years, physiological pacing (conduction system pacing) has helped to mitigate some of these concerns by preserving ventricular synchrony, even as the underlying disease progresses and systolic function deteriorates. This approach may maintain adequate mechanical coordination without the need for an additional coronary sinus lead, thus reducing the need for repeat interventions. Given the current availability and feasibility of the technique, a more proactive strategy in selected young patients appears advisable to reduce the risk of SCD.
Funding Support and Author Disclosures
The author has reported that he has no relationships relevant to the contents of this paper to disclose.
Footnotes
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References
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