Myocardial Work Appraisal in Transthyretin Cardiac Amyloidosis and Nonobstructive Hypertrophic Cardiomyopathy

Global left ventricular (LV) myocardial work (MW) indexes can be recognized at ultrasound imaging from the LV pressure/global longitudinal strain (GLS) loop analysis. A total of 4 indexes, global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), have been demonstrated to overcome the methodological limitations of GLS and provide useful information on myocardial dysfunction in some clinical settings. Although impaired MW indexes have been demonstrated in patients with transthyretin cardiac amyloidosis (ATTR) or with nonobstructive hypertrophic cardiomyopathy (HCM), there are no comparative studies at present. This study aimed to describe the characteristics of MW in both these clinical settings compared with patients with well-controlled hypertension (HTN). A total of 83 patients, 32 with ATTR (aged 70 ± 11 years, 32% mutated, 68% wild-type, 72% men), 29 with HCM (aged 57 ± 17 years), and 22 HTN controls (aged 56 ± 5.6 years, 59% men) were prospectively enrolled at 2 clinical centers. All participants had New York Heart Association class I or II. Overall, the LV mass index was greater in both study groups than in HTN, whereas the LV ejection fraction (EF) was significantly lower in ATTR compared with other groups. Based on this finding, patients with ATTR were further divided into 2 subgroups: ATTR1 (LVEF ≤0.50), n = 14 (44%) and ATTR2 (LVEF >0.50), n = 18 (56%). Overall, the GWI and GCW were lower in all ATTR patients (mostly in ATTR1) than in the other groups (p <0.001), whereas only small differences in GWE and none in GWW were found among the groups. Of interest, the pairwise comparison and receiver operating characteristic analysis in preserved LVEF patients showed that GWI was a better discriminator of ATTR2 from HCM patients than GLS, with the cut-off value ≤1,419 mm Hg% (89% sensitivity; 55% specificity; p = 0.013). In conclusion, MW analysis was confirmed to be a modern way to investigate myocardial function in patients with hypertrophic phenocopies. GWI and GCW were more impaired in patients with ATTR compared with HCM and HTN controls. Furthermore, this study likely revealed an additional discriminative value of GWI over GLS alone in preserved LVEF settings.

358 A POSSIBLE RARE CASE OF VENTRICULAR LIPOMATOSIS: A STIMULUS FOR A PANORAMA OF FATTY CARDIAC LESIONS

We exhibit the case of a 75 years-old man who undertook cardio-oncological assessment for Non-Hodgkin Lymphoma: baseline echo revealed typical features of lipomatous hypertrophy of the interatrial septum (LHIS) and an apical hypoechoic left ventricle (LV) lesion. Five years before, the patient performed MRI (Magnetic Resonance Imaging), which confirmed LHIS, but superabundant epicardial fat extended to the right ventricle and the apical junction between the two ventricles, both characterized by normal ejection fraction, and surrounded the origin of the pulmonary trunk. LV lateral and inferior walls presented lipomatous metaplasia foci and no history or ECG sign of previous myocardial injury could be pointed out. A slight band of late gadolinium enhancement at the basal infero-lateral wall of LV was highlighted. The patient referred episodes of fainting: the Holter-ECG showed pronounced bradycardia which couldn't be explained by other secondary causes. So a bicameral pace-maker was implanted. During our ambulatory evaluation, we decided to repeat MRI, which showed no difference in comparison with the previous one, so excluding malignant degeneration of the fatty mass surrounding the heart. Despite older age and the lack of sudden cardiac death family history we searched for pathognomonic arrhythmogenic cardiomyopathy (ACM) mutations. In consideration of the new evidence of the metabolic risk associated with abundant epicardial fat (EF) we asked for updated laboratory dosage of plasma glucose, LDL cholesterol and triglycerides and we recommended stricter control of blood pressure.

From 4% to 52% of cardiac mass is made up of fat but only EF interacts with myocardium and coronary arteries. Anomalous growth of fat in the heart can present itself as LHIS, excessive lipomatous infiltration or cardiac lipomas (real capsulated tumors) but also ACM is histologically characterized by fibrofatty replacement of cardiomyocites. Overabundant and inflammed EF is now considered a surrogate of metabolic risk and is associated with multivessel coronary disease, the finding of chronic total occlusions (CTO) and microvascular angina.

Identifying fatty heart lesions and defining their clinical and prognostic role remains an intriguing challenge. We suggest a general binary way to follow: the “mechanic one” for lipomas or lipomatous infiltration, that is paying attention to compression phenomena or the generation of arrhythmias, and the “metabolic one”, in other words optimizing cardiovascular prevention when EF is too much. A careful research of imaging features of ACM can't be omitted.

354 THE ADDED VALUE OF MYOCARDIAL WORK IN EARLY DETECTION OF SYSTOLIC DYSFUNCTION IN CARDIAC AMYLOIDOSIS

Aim

The involvement of the heart represents the main determinant of mortality and morbidity for patients with systemic amyloidosis (SA). In cardiac amyloidosis (CA), numbered among the clearest examples of restrictive cardiomyopathies, EF (ejection fraction) often keeps itself preserved (≥ 50%) but this doesn't mean LV (left ventricle) systolic function couldn't be impaired, even in the early stages of disease. In this survey we searched for echocardiographic signs of early systolic impairment in CA: among them we adopted the analysis of myocardial work (MW), an emerging less load-dependent tool for the evaluation of cardiac performance.

Methods

We chose a cohort of patients (n=20; mean age 69±13 years) with AL or ATTR CA and we compared them with a control group (n=18; mean age 62±17 years) without evident cardiac damage. We examined their systolic and diastolic function and we calculated multilayer strain and all the contributors of MW from speckle tracking echocardiography.

Results

We found a statistically relevant difference in cardiac mass (138±35 versus 83±23 g/m2) and in signs of both systolic and diastolic function (LAVi, TR Vmax, E/e’) worsening between patients with CA and the control group. In CA average EF was 52±11% while the reduction in Global Longitudinal Strain (GLS) was significant, regardless of the considered wall layer and the stage of diastolic impairment. For our patients ejection fraction to strain ratio (EFSR, 4,41±1,38 vs 3,04±0,55), a simple way to quantify apical sparing, better underlined the dissociation between EF and strain than apex to base ratio. In CA we identified a dramatic decrease in Global Work Index (954±278 vs 2089±354 mmHg%) and Global Constructive Work (1103±323 vs 2376±390 mmHg%), with no significant difference between AL and ATTR amyloidosis.

Conclusions

The infiltration by amyloid and the consequent increase in cardiac mass lead to an early and often severe weakening of the intrinsic contractility of the heart in both AL and ATTR amyloidosis, even when ejection fraction is normal or slightly reduced. Therefore, we suggest the analysis of MW starting from the first echocardiographic evaluation in patients with known SA or multiple myeloma.