HYPERTROPHIC cardiomyopathy (HCM) is an inherited cardiac condition characterised by abnormal thickening of the myocardium, affecting around 1 in 500 individuals and carrying a risk of arrhythmia and sudden cardiac death.1
New findings indicate that a cardiac MRI-derived metric, the left atrioventricular coupling index (LACI), improves sudden cardiac death risk prediction in hypertrophic cardiomyopathy beyond current guideline-based models.2
MRI-derived LACI adds to HCM risk tools
Risk stratification remains central in HCM, particularly as patients may remain asymptomatic despite elevated risk¹. LACI reflects atrial–ventricular interaction and is calculated as the ratio of left atrial end-diastolic volume to left ventricular end-diastolic volume.
The study evaluated whether this index adds prognostic value to established imaging markers such as late gadolinium enhancement (LGE), a marker of myocardial fibrosis, and left ventricular ejection fraction.
2,240-patient study links LACI to Sudden Cardiac Death
The retrospective analysis included 2,240 patients with hypertrophic cardiomyopathy, followed for a mean of 4 years². During this period, 128 patients (5.7%) experienced sudden cardiac death events.
Patients with events had higher LACI (39% ± 28% vs 33% ± 23%), greater LGE burden (12.1 ± 8.6% vs 6.4 ± 4.3%), and lower left ventricular ejection fraction (48% ± 15% vs 65% ± 13%).²
Independent Predictor Beyond ESC Risk Models
After adjustment for conventional risk factors and LGE, LACI remained an independent predictor of sudden cardiac death, with hazard ratios between 1.44 and 1.46 (95% CI 1.3–1.6; P < 0.001)².
Adding LACI to ESC and ACC/AHA risk models improved predictive performance. These findings suggest LACI and LGE provide complementary prognostic information in hypertrophic cardiomyopathy.
Clinical Implications and Future Validation
The findings suggest LACI may refine hypertrophic cardiomyopathy risk stratification by providing additional prognostic information beyond late gadolinium enhancement and conventional risk factors.
For clinicians, this may support more precise identification of patients at increased risk of sudden cardiac death and guide management decisions.
However, the retrospective design limits causal inference, and the absence of demographic data in the abstract restricts assessment of sex and ethnic representation, which may affect generalisability.
Further research is needed to determine how LACI can be integrated into existing risk calculators and whether its use translates into improved clinical outcomes.
References
1 National Health Service (NHS) England. Hypertrophic cardiomyopathy. 2023. Available at: https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/hypertrophic-cardiomyopathy/. Last accessed 29 April 2026.
2 Zhang D et al. Assessment of left atrioventricular coupling index in hypertrophic cardiomyopathy: improving risk stratification with CMR. Clin Radiol. 2026;DOI: 10.1016/j.crad.2026.107369.
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