Incremental prognostic value of left atrial strain in apical hypertrophic cardiomyopathy: a cardiovascular magnetic resonance study.

Objectives: This study aimed to evaluate the prognostic value of left atrial (LA) strain in patients with apical hypertrophic cardiomyopathy (ApHCM), as assessed by cardiac magnetic resonance (CMR) imaging.

Methods: Four hundred and five consecutive patients with ApHCM who underwent CMR examination were retrospectively included. The study endpoint included all-cause death, heart transplant, aborted sudden cardiac death, hospitalization for heart failure, stroke, and new-onset atrial fibrillation (AF).

Results: After a median follow-up of 97 months, 75 patients (18.5%) reached the endpoint. Patients were divided into two groups based on the median LA reservoir strain of 29.4%. The group with lower LA reservoir strain had thicker maximum wall thickness, greater late gadolinium enhancement extent, and smaller end-diastolic volume index, stroke volume index, and cardiac index (all p < 0.02). For LA parameters, this subgroup showed greater diameter and volume index and worse ejection fraction, reservoir, conduit, and booster strain (all p < 0.001). In the multivariable model, age (HR 1.88, 95% CI: 1.06-3.31, p = 0.030), baseline AF (HR 2.95, 95% CI: 1.64-5.28, p < 0.001), LA volume index (LAVi) (HR 2.07, 95% CI: 1.21-3.55, p = 0.008) and LA reservoir strain (HR 2.82, 95% CI: 1.51-5.26, p = 0.001) were all associated with the outcome. Adding LAVi and LA reservoir strain in turn to the multivariable model (age and baseline AF) resulted in significant improvements in model performance (p < 0.001).

Conclusion: In ApHCM patients, LA reservoir strain is independently associated with cardiovascular risk events and has an incremental prognostic value.

Clinical Relevance Statement: Left atrial reservoir strain measured by cardiac magnetic resonance is highly correlated with the prognosis of apical hypertrophic cardiomyopathy and has potential incremental value in the prognosis of major adverse cardiac events.

Key Points: Left atrial (LA) strain parameters may be useful for risk stratification and treatment of apical hypertrophic cardiomyopathy (ApHCM). Apical hypertrophic cardiomyopathy (ApHCM) is independently associated with LA morphology and function. Cardiac MR examination, especially its feature-tracking technology, provides the possibility to prognosticate ApHCM at an early stage.