Determinants of left atrial reservoir strain and diagnostic potential for cardiac amyloidosis in pathological left ventricular hypertrophy.

Background: Left ventricular (LV) long-axis shortening at the cardiac base is a determinant of left atrial (LA) reservoir function. Cardiac amyloidosis (CA) is characteristic of amyloid deposition predominantly in the LV basal wall. We investigated the relationship between LV basal strain and LA reservoir strain among patients with pathological LV hypertrophy and subsequently evaluated the diagnostic ability of LA reservoir strain to identify CA etiology and its predictive value for heart failure hospitalization.

Methods: We retrospectively analyzed 341 patients with LV hypertrophy. Cardiac etiologies were diagnosed by tissue biopsy, cardiac magnetic resonance imaging or ^99mTc-PYP scintigraphy. LV basal strain and LA reservoir strain were analyzed.

Results: Patients were diagnosed with CA (n = 75) and other etiologies (n = 266). LV basal strain was correlated with LA reservoir strain in the CA group (r = 0.58, p < 0.01) and the non-CA group (r = 0.44, p < 0.01). A binary logistic regression analysis showed that relative apical sparing of longitudinal strain, septal E/e' and LA reservoir strain had the ability to discriminate between the CA and non-CA groups (p < 0.01 for all). The area under the curve for relative apical sparing of longitudinal strain had a stronger ability than LA reservoir strain to discriminate CA from non-CA etiologies (0.90 versus 0.81, respectively; p < 0.01). During the follow-up period (median 2.7 years), the incidence of heart failure hospitalization was higher in the CA group than the non-CA group (35% versus 14%, respectively; p < 0.01). According to univariate Cox regression analysis, three LA factors (LA reservoir strain, E/e' and LA volume index) were associated with heart failure hospitalization in the non-CA group (p < 0.05 for all).

Conclusions: LA reservoir strain was associated with LV basal strain among patients with pathological LV hypertrophy. Echocardiographic assessment of LA reservoir strain might add diagnostic value to identify CA etiology in these patients.