Left atrial morphology and function in atrial amyloidosis: a 2D feature strain echocardiographic

Purpose: Familial amyloid polyneuropathy (FAP), an autosomal dominant disease characterized by the systemic deposition of transthyretin, can involve atria. Cardiac magnetic resonance (CMR) by late gadolinium enhancement (LGE) permits to identify atrial damage due to transthyretin deposition. Nowadays, two dimensional strain echocardiography (SE) enables to quantify, non-invasively and accurately, left atrial (LA) function (reservoir, conduit and contraction). The purpose of the study is to assess LA function in atrial amyloidosis. Methods: 25 patients (53+13 years, 11 female) affected by FAP and a control group of 12 asymptomatic subjects (45+13 years, 6 female), were enrolled. On the same day, all subjects underwent SE imaging, and CMR. SE parameters were obtained on apical views (4-and 2-chambers). LGE -CMR was used to evaluate atrial deposition of transthyretin in FAP patients. SE was performed off-line, using a dedicated software (MyLab Desk), by placing at the edge of left atrial endocardium several points. LA strain pattern is characterized by a positive wave that peaks at the end of ventricular systole (peak atrial longitudinal strain, PALS), followed by a positive peak in early diastole (early atrial longitudinal strain, early ALS) and a negative peak (NP) in late diastole. Furthermore, can be derived the precontraction ALS (difference between PALS and early ALS) and late ALS (sum in absolute value of NP and precontraction ALS). PALS represents LA reservoir function, precontraction and early ALS the conduit phase, and NP and late ALS the LA contraction. Results: 11 FAP patients had LGE atrial involvement (LGE atrial group, 56 + 13.7years) and 14 FAP patients showed no LGE (no-LGE atrial group 50.7 + 12 years). PALS was significantly lower in LGE atrial group (26+11.9) with respect to no-LGE atrial group (59.6+33.1, p = 0.007) and controls (57.9+12.7, p =0.02); while it was similar (p = 1) between no-LGE atrial group and controls. Early-ALS was lower (p = 0.012) in LGE atrial group (11.9+9.4) with respect to controls (43.5+22); on the contrary the difference was not statistically significant (p = 0.085) between LGE atrial group and no-LGE atrial group (35.3+30); early-ALS was similar between no-LGE atrial group and controls. No significant differences were found in global ALS, precontraction ALS and NP among groups. Conclusion: LAreservoir and conduit are impaired in patients with atrial amyloidosis