Delayed identification of monoclonal protein is associated with early death in isolated cardiac AL amyloidosis.

BACKGROUND: Early identification of immunoglobulin light-chain amyloidosis (AL) is crucial due to its rapid progression. Monoclonal light-chain (M-LC) testing is the first step in the diagnostic workup for patients with suspected cardiac amyloidosis (CA). We aimed to determine whether the time interval between the first CA suspicion and M-LC testing can be related to AL amyloidosis survival outcomes. METHODS: All patients (n = 94) with isolated cardiac AL amyloidosis diagnosed at our center between 2016 and 2020 were included. Those with pre-existing known monoclonal protein (monoclonal gammopathy of undetermined significance or smoldering multiple myeloma) were excluded. Time intervals to diagnostic tests and diagnosis were calculated and assessed for their survival prediction ability. RESULTS: The time interval between first CA suspicion (on echocardiography) and M-LC testing correlated with early mortality, and the best cutoff predicting survival, was 6 weeks. The 26 patients (∼28% of entire cohort) who underwent M-LC-studies >6 weeks after first suspicion more frequently presented Mayo stage IIIb (65% vs. 35%, p = .008), showing poorer overall survival than those (n = 68, 72%) referred for early M-LC studies (median 3 vs. 14 months, p = .039). CONCLUSIONS: Monoclonal protein testing should be the first-step in the diagnostic workup for patients with echocardiographic/other instrumental red flags raising CA suspicion.

A real-life study of daratumumab combinations in newly diagnosed patients with light chain (AL) amyloidosis.

Daratumumab-based regimens are the new standard of care for newly diagnosed patients with AL amyloidosis based on the results of the ANDROMEDA study. However, real-world data on daratumumab efficacy in upfront therapy in unselected patients are scanty. In the framework of a prospective observational study, we investigated the efficacy and safety of daratumumab in 88 newly diagnosed patients, including subjects with IIIb cardiac stage (26%) or myeloma defining events (29%). Daratumumab was administered with bortezomib in 50 (56%) patients, lenalidomide in 31 (35%), and monotherapy in 7 (8%). The rate of serious adverse events was low (16%). The overall hematologic response rate was 75% with 52 (59%) patients attaining at least a very good partial response (VGPR) at six months. Amongst patients evaluable for organ response, the rate of cardiac and renal responses at 6 months was 31% and 21%, respectively. Comparing stage IIIb patients with the remaining ones, the rate of profound hematologic response was not significantly different (≥VGPR 57% vs. 59%, p 0.955) likewise the rate of cardiac (33% vs. 30%, p 0.340) and renal (40% vs. 16%, p 0.908) responses. Daratumumab-based regimens demonstrated to be safe and effective in treatment-naïve AL amyloidosis even in advanced stage disease.

Predictive value of unshielded magnetocardiographic mapping to differentiate atrial fibrillation patients from healthy subjects.

BACKGROUND: P-wave duration, its dispersion and signal-averaged ECG, are currently used markers of vulnerability to atrial fibrillation (AF). However, since tangential atrial currents are better detectable at the body surface as magnetic than electric signals, we investigated the accuracy of magnetocardiographic mapping (MCG), recorded in unshielded clinical environments, as predictor of AF occurrence. METHODS: MCG recordings, in sinus rhythm (SR), of 71 AF patients and 75 controls were retrospectively analyzed. Beside electric and magnetic P-wave and PR interval duration, two MCG P-wave subintervals, defined P-dep and P-rep, were measured, basing on the point of inversion of atrial magnetic field (MF). Eight parameters were calculated from inverse solution with "Effective Magnetic Dipole (EMD) model" and 5 from "MF Extrema" analysis. Discriminant analysis (DA) was used to assess MCG predictive accuracy to differentiate AF patients from controls. RESULTS: All but one (P-rep) intervals were significantly longer in AF patients. At univariate analysis, three EMD parameters differed significantly: in AF patients, the dipole-angle-elevation angular speed was lower during P-dep (p < 0.05) and higher during P-rep (p < 0.001) intervals. The space-trajectory during P-rep and the angle-dynamics during P-dep were higher (p < 0.05), whereas ratio-dynamics P-dep was lower (p < 0.01), in AF. At DA, with a combination of MCG and clinical parameters, 81.5% accuracy in differentiating AF patients from controls was achieved. At Cox-regression, the angle-dynamics P-dep was an independent predictor of AF recurrences (p = 0.037). CONCLUSIONS: Quantitative analysis of atrial MF dynamics in SR and the solution of the inverse problem provide new sensitive markers of vulnerability to AF.

Magnetocardiographic classification and non-invasive electro-anatomical imaging of outflow tract ventricular arrhythmias in recreational sport activity practitioners.

Ventricular arrhythmias (VAs) with left bundle-branch-block and inferior axis morphology (LBBB-IA), suggestive of outflow tract (OT) origin, are a challenge in sports medicine because they can be benign or expression of a silent cardiomyopathy. Non-invasive classification is essential to plan ablation strategy if required. We aimed to evaluating magnetocardiographic (MCG) discrimination of OT-VAs site of origin (SoO). MCG and ECG data of 26 sports activity practitioners, with OT-VAs were analyzed. OT-VAs-SoO was classified with discriminant analysis (DA) of 8 MCG parameters and with invasively-validated ECG algorithms. MCG inverse source-localization merged with magnetic resonance (CMR) provided three-dimensional electro-anatomical imaging (MCG 3D-EAI). ECG classification was univocal in 73%. MCG-DA differentiated right ventricular OT from aortic sinus cusp VAs, with 94.7% accuracy. MCG 3D-EAI confirmed OT-VAs-SoO in CMR images. In cases undergoing ablation, MCG 3D-EAI was confirmed by CARTO 3D-EAI. MCG-DA improves non-invasive classification of OT-VAs-SoO. Further comparison with interventional results is required.

Unshielded magnetocardiography: Repeatability and reproducibility of automatically estimated ventricular repolarization parameters in 204 healthy subjects.

BACKGROUND: Magnetocardiographic mapping (MCG) provides quantitative assessment of the magnetic field (MF) induced by cardiac ionic currents, is more sensitive to tangential currents, and measures vortex currents undetectable by ECG, with higher reported sensitivity of MCG ventricular repolarization (VR) parameters for earlier detection of acute myocardial ischemia. Aims of this study were to validate the feasibility of in-hospital unshielded MCG and to assess repeatability and reproducibility of quantitative VR parameters, considering also possible gender- and age-related variability. METHODS: MCG of 204 healthy subjects [114 males-mean age 43.4 ± 17.3 and 90 females-mean age 40.2 ± 15.7] was retrospectively analyzed, with a patented proprietary software automatically estimating twelve VR parameters derived from the analysis of the dynamics of the T-wave MF extrema (five parameters) and from the inverse solution with the effective magnetic dipole model giving the effective magnetic vector components (seven parameters). MCG repeatability was calculated as coefficient of variation (CV) ±standard error of the mean (SEM). Reproducibility was assessed as intraclass correlation coefficient (ICC). RESULTS: The repeatability of all MCG parameters was 16 ± 1.2 (%) (average CV ± SEM). Optimal (ICC > 0.7) reproducibility was found for 11/12 parameters (mean values) and in 8/12 parameters (single values). No significant gender-related difference was observed; six parameters showed a strong/moderate correlation with age. CONCLUSION: Reliable MCG can be performed into an unshielded hospital ambulatory, with repeatability and reproducibility of quantitative assessment of VR adequate for clinical purposes. Wider clinical use is foreseen with the development of multichannel optical magnetometry.