Left atrial strain measured on magnetic resonance imaging (MRI) in patients with cardiac amyloidosis: A new prognosis marker of rhythmic cardiac events

Abstract

In recent years, studies on left atrial strain (LAS) have been increasing and have demonstrated a potential interest for the diagnosis and the prognosis of cardiomyopathies such as hypertrophic cardiomyopathies or cardiac amyloidosis (CA). On MRI, there is a lack of knowledge about the impact prognosis of LAS on patients with CA. We performed on the same day an echocardiography and a MRI to a prospective cohort of patients with confirmed CA to analyse LA volume, function and strain. We recruited 19 patients with CA (73 ± 12 years, 74% of men, all in sinusal rhythm). During a mean follow-up of 13 (range 10–17) months, 10 rhythmic cardiac events (53%) occurred: eight new supraventricular tachycardia and two pacemaker implantations for high-degree atrioventricular block. By MRI, mean left ventricular ejection fraction (LVEF) was 63 ± 11%, mean LV thickness was 20 ± 4 mm, mean LA volume index was 37 ± 12 mL/m 2 , mean LAEF was 29.1 ± 14%, mean LA peak longitudinal strain (PALS) was 11 ± 6%, mean LA peak contraction strain (PACS) was 5 ± 4%. There were no differences between the two groups (cardiac events or not) for: LVEF, LV volume, LV hypertrophy, LV strain, LA volume and LAEF on echocardiography as on MRI. PALS and PACS were not discriminant parameters on echo, while, on MRI, mean PALS, and especially, two-chambers PALS were more impaired on the cardiac rhythmic events group (7.8% versus 14.3% and 7.4% versus 16.7%; P -value < 0.03). The present study is the first to suggest a link between LA peak longitudinal strain (PALS) by MRI and the occurrence of rhythmic cardiac event on patients with a CA.