Left atrioventricular coupling index in hypertrophic cardiomyopathy and risk of new-onset atrial fibrillation

Funding Acknowledgements Type of funding sources: None. Background In patients with hypertrophic cardiomyopathy (HCM) accurate risk stratification for new onset atrial fibrillation (AF) has important prognostic implications. Left atrioventricular coupling index (LACI) has been recently associated with the occurrence of AF in patients without history of cardiovascular disease. Purpose The objective of this study was to investigate the association between LACI and new onset AF in HCM patients and its incremental value over conventional left atrial (LA) parameters. Methods A total of 373 HCM patients without history of AF (48 ± 17 years, 66% men) were evaluated by transthoracic echocardiography. LACI was defined by the ratio of the LA end-diastolic volume divided by the LV end-diastolic volume. The cut-off value for LACI (≥40%) to identify LA-left ventricular (LV) uncoupling was chosen based on the risk excess of new-onset AF described with a spline curve analysis. Cox proportional hazard models were used to evaluate the association between LACI and the occurrence of AF. Results The median LACI was 38% (interquartile range: 24-56) and LA-LV uncoupling (LACI ≥40%) was observed in 171 (45.8%) patients. During a mean follow-up of 11.0 ± 5.6 years, 118 subjects (31.6%) developed new-onset AF. The cumulative event-free survival at 10 years was 53% for patients with LA-LV uncoupling (LACI ≥40%) versus 94% for patients without LA-LV uncoupling (LACI Conclusion Greater LACI, indicative of LA-LV uncoupling, was independently associated with the occurrence of new-onset AF in patients with HCM and demonstrated a stronger risk discrimination power compared to conventional LA parameters. This simple ratio may be easily implemented in clinical practice to improve risk stratification for new-onset AF in HCM. Abstract Figure. Incident AF according to LACI Abstract Figure.