Left Atrial Morphology, Size and Function in Patients With Transthyretin Cardiac Amyloidosis and Primary Hypertrophic Cardiomyopathy　– Comparative Strain Imaging Study –

Abstract

Background:We sought to assess left atrial (LA) morphology and function in patients with transthyretin cardiac amyloidosis (TTR-CA) and hypertrophic cardiomyopathy (HCM). Primarily, longitudinal deformation (reservoir) and pump function were the focus of vector-velocity strain echocardiography imaging. Methods and Results:The study group comprised 32 patients (mean age 57.7±15.4 years, 16 in each group), and 15 healthy controls. Diagnosis of TTR-CA was based on echocardiography and either gadolinium-enhanced (LGE) cardiac magnetic resonance (cMRI) or radionuclide imaging. At baseline, there were no differences in age, body surface area, blood pressure and risk factors among the groups. Left ventricular (LV) mass was greater in patients than in controls, and slight LA dilatation was found in the TTR-CA group. LA reservoir was 14.1±4.7% in TTR-CA, 20.0±5.6% in HCM, and 34.0±11.8% in controls (<0.001). In addition, LA pump function chiefly was impaired in the former group, irrespective of LA chamber size and LV ejection fraction. LGE in the atrial wall was seen in 9/10 TTR-CA versus 0/8 HCM patients undergoing cMRI (P<0.001). LA reservoir ≤19% and pump function ≤-1.1% best discriminated TTR-CA from HCM patients in the receiver-operating characteristic analysis. Conclusions:LA reservoir and pump function were significantly impaired in both TTR-CA and HCM patients compared with controls, but mainly in the former group, irrespective of LA volume and LV ejection fraction, likely caused by a more altered LA wall structure. (Circ J 2016; 80: 1830 -1837

Left atrial structure and function in cardiac amyloidosis

“…29 De Gregorio et al showed an impairment in LA reservoir and pump function among patients with TTR-CA and HCM (n=16 in each group), as compared to normal controls, but mainly in the former group, irrespective of LA volume and LV ejection fraction. 30 Our results are consistent with such findings. Indeed, we showed that LA conduit and active functions were impaired in all the three etiologies of CA (Table 3).…”

Reduced left atrial myocardial deformation irrespective of cavity size: a potential cause for atrial arrhythmia in hereditary transthyretin amyloidosis

“…This is an unexpected finding, since the LA, described as the "Cinderella of the left heart", is commonly enlarged in any form of LV disease [19,20]. This finding therefore suggests that LA myocardial infiltration with the amyloid limits LA distension, as has previously been found in cardiac examinations on patients with AL or ATTR amyloidosis [7,8,21]. This suggestion is also supported by the significantly reduced LA SR function during the atrial contraction phase, particularly in patients with increased LV wall thickness.…”

“…Recently, LA myocardial functional assessment has become possible using speckle tracking echocardiography and 2D strain technology, from which myocardial segmental global strain and derived strain rate (SR) can be evaluated during different phases of the cardiac cycle. These variables have been tested in cardiac amyloidosis and shown to be abnormal in ATTR amyloidosis patients irrespectively of LA size [8,9]. However, no previous study has evaluated the relation between LA function using 2 D strain and atrial arrhythmias.…”

Diagnostic performance of imaging investigations in detecting and differentiating cardiac amyloidosis: a systematic review and meta‐analysis

“…Of the 2947 studies, we identified 27 meeting the inclusion criteria, including data on 3493 patients ( Figure ). Twenty‐two studies evaluated the performance of CMR in diagnosing either cardiac amyloidosis or ATTR amyloidosis, with a further five studies assessing the diagnostic performance of nuclear scintigraphy . Seventeen studies assessing the performance of index tests in the diagnosis of cardiac amyloidosis included patients with a range of cardiac conditions, whereas 9 out of 11 studies diagnosing ATTR amyloidosis included patients with ATTR or AL amyloidosis only.…”

“…Studies evaluating the performance of CMR in this setting all used the presence of LGE in varying regions of the heart as the index test ( Figure ). Left ventricular LGE was defined by presence in the LV myocardium or any of the 17 LV segments . One study described subendocardial LGE when there was global subendocardial involvement but no transmural LGE; another study defined it as global subendocardial LGE irrespective of transmural involvement .…”