A CMR study of left atrial mechanics in hypertrophic cardiomyopathy: left atrial function predicts paroxysmal atrial fibrillation

Background: Atrial fibrillation is a frequent complication in HCM, often precipitating heart failure or stroke. Identification of patients at risk of developing AF may have implications for management. While left atrial (LA) volumes have been shown to increase the risk of AF, we hypothesized that LA function is an important predictor of risk.

Methods: 72 patients (36 without AF-HCM SR); 36 with PAF-HCM PAF) were compared. PAF and SR patients were matched on an individual basis for age, gender, and HCM morphology. Strain analysis with Velocity Vector Imaging software was performed on cine SSFP images obtained from CMR to assess LA volumes and function. All patients were in sinus rhythm at the time of CMR.

Results: see Table.

Conclusions: In HCM patients with PAF, LA function is impaired even in the presence of sinus rhythm. This difference is present even in patients with similar degrees of hypertrophy, LVOT obstruction, and mitral regurgitation, suggesting the likelihood of an underlying atrial myopathy. The presence of LA dysfunction in patients with HCM provides an incremental measure of risk of PAF over and above LA volume.