Left ventricular longitudinal shortening at cardiac base as a determinant of left atrial reservoir function in cardiac amyloidosis

Abstract

Abstract Objective To investigate a mechanistic determinant of left atrial (LA) reservoir function in patients presenting left ventricular (LV) hypertrophy, and clarify diagnostic and prognostic values of LA reservoir strain in patients with cardiac amyloidosis (CA). Methods Three-hundred sixty patients (median age: 68 years, male gender: 65%) with left ventricular hypertrophy (LVH) assessed by echocardiography were retrospectively included. The LVH etiologies were diagnosed by any of biopsy, cardiac magnetic resonance imaging or 99mTc-PYP scintigraphy. LV segmental longitudinal strain was estimated from apical three views, and LA reservoir strain was measured from an apical 4-chamber view. Results The LVH etiologies were confirmed with CA in 81 patients, hypertensive heart disease in 87 patients, hypertrophic cardiomyopathy in 143 patients, and miscellaneous disorders in 49 patients. The median (25th, 75th percentile) value of LV ejection fraction was 59% (48–67). LV basal longitudinal strain and LA reservoir strain were significantly reduced in patients with CA compared with those with other etiologies; LV basal strain: 5.4% (3.9–8.7) vs. 11.9% (9.3–14.6), LA reservoir strain: 9.2% (6.3–12.3) vs. 17.5% (11.3–24.1), p<0.01 respectively. LV basal strain was significantly correlated with LA reservoir strain in patients with CA (r=0.57, p<0.01) and in those with other etiologies (r=0.45, p<0.01). The area under the receiver-operating characteristic curves of LA reservoir strain and E/e' (0.78 and 0.74) to identify CA etiology were significantly larger than that of LA volume index (0.62) (p<0.01). During the follow-up period (median 2.9 years), 53 patients experienced heart failure hospitalization. The Cox regression model including age, gender, LV ejection fraction, E/e' and LA reservoir strain showed that male gender (hazard ratio: 0.46, p=0.03), E/e' (hazard ratio: 1.04, p<0.01) and LA reservoir strain (hazard ratio: 0.94, p<0.01) independently predicted heart failure hospitalization. Conclusions The decrease of LV longitudinal shortening at cardiac base could worsen LA reservoir function especially in patients with CA. LA reservoir strain might be an alternative measure to identify CA etiology and have a predictive value of heart failure hospitalization in patients with LV hypertrophy. Funding Acknowledgement Type of funding sources: None.