Transthyretin amyloid cardiomyopathy (ATTR-CM) results in a restrictive cardiomyopathy caused by extracellular deposition of transthyretin, normally involved in the transportation of the hormone thyroxine and retinol-binding protein, in the myocardium. Enthusiasm about ATTR-CM has grown as a result of 3 simultaneous areas of advancement: Imaging techniques allow accurate noninvasive diagnosis of ATTR-CM without the need for confirmatory endomyocardial biopsies; observational studies indicate that the diagnosis of ATTR-CM may be underrecognized in a significant proportion of patients with heart failure; and on the basis of elucidation of the mechanisms of amyloid formation, therapies are now approved for treatment of ATTR-CM. Because therapy for ATTR-CM may be most effective when administered before significant cardiac dysfunction, early identification of affected individuals with readily available noninvasive tests is essential. This scientific statement is intended to guide clinical practice and to facilitate management conformity by covering current diagnostic and treatment strategies, as well as unmet needs and areas of active investigation in ATTR-CM.

Right ventriculo-arterial coupling in pulmonary hypertension can be studied with standard RHC and CMR. Arterial load increases with disease severity whereas contractility cannot progress in parallel, leading to severe uncoupling.

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The study comprised 100 consecutive patients with known or suspected pulmonary hypertension (PH; 53 ± 16 years, 73% women) who underwent same-day right heart catheterization (RHC) and CMR. Increased PVR was defined from RHC as >3 WU (n = 66, 66%). From CMR cine and phase-contrast images, right ventricular (RV) volumes and ejection fraction (RVEF), pulmonary artery (PA) flow velocities and areas, and cardiac output were quantified. The best statistical model to estimate PVR was obtained from a derivation cohort (n = 80) based on physiological plausibility and statistical criteria. Validity of the model was assessed in the remaining 20 patients (validation cohort). The CMR-derived model was: estimated PVR (in WU) = 19.38 - [4.62 × Ln PA average velocity (in cm/s)] - [0.08 × RVEF (in %)]. In the validation cohort, the correlation between invasively quantified and CMR-estimated PVR was 0.84 (P < 0.001). The mean bias between the RHC-derived and CMR-estimated PVR was -0.54 (agreement interval -6.02 to 4.94 WU). The CMR model correctly classified 18 (90%) of patients as having normal or increased PVR (area under the receiver operator characteristics curve 0.97; 95% confidence interval: 0.89-1.00). CONCLUSIONS Non-invasive estimation of PVR using CMR is feasible and may be valuable for PH diagnosis and/or follow-up.

The neuromuscular junction (NMJ) is a specialized synapse with a complex molecular architecture that provides for reliable transmission between the nerve terminal and muscle fiber. Using linkage analysis and whole-exome sequencing of DNA samples from subjects with distal hereditary motor neuropathy type VII, we identified a mutation in SLC5A7, which encodes the presynaptic choline transporter (CHT), a critical determinant of synaptic acetylcholine synthesis and release at the NMJ. This dominantly segregating SLC5A7 mutation truncates the encoded product just beyond the final transmembrane domain, eliminating cytosolic-C-terminus sequences known to regulate surface transporter trafficking. Choline-transport assays in both transfected cells and monocytes from affected individuals revealed significant reductions in hemicholinium-3-sensitive choline uptake, a finding consistent with a dominant-negative mode of action. The discovery of CHT dysfunction underlying motor neuropathy identifies a biological basis for this group of conditions and widens the spectrum of disorders that derive from impaired NMJ transmission. Our findings compel consideration of mutations in SLC5A7 or its functional partners in relation to unexplained motor neuronopathies.

Sarcoidosis is a systemic disease with a favorable prognosis, high remission rate, and low mortality. Cardiac involvement alters this prognosis. Clinical manifestations most commonly include arrhythmias, conduction abnormalities, and congestive heart failure. Treatment includes immunosuppressant therapy, permanent pacemakers in the setting of conduction abnormalities, and implantable cardioverter-defibrillators in patients at risk for sudden cardiac death. Risk stratification for sudden cardiac death is essential in otherwise asymptomatic patients who have suspected cardiac sarcoidosis.

Background: In the REDUCE LAP-HF II trial, implantation of an atrial shunt device did not provide, overall, clinical benefit for patients with heart failure and preserved or mildly reduced ejection fraction (HFpEF/HFmrEF). However, pre-specified analyses identified differences in response in subgroups defined by pulmonary artery systolic pressure during submaximal exercise, right atrial (RA) volume, and sex. Shunt implantation reduces left atrial (LA) pressures but increases pulmonary blood flow, which may be poorly tolerated in patients with pulmonary vascular disease (PVD). Based upon these results, we hypothesized that patients with latent PVD, defined as elevated pulmonary vascular resistance (PVR) during exercise, might be harmed by shunt implantation, and conversely that patients without PVD might benefit. Methods: REDUCE LAP-HF II enrolled 626 patients with HF, EF ≥40%, exercise pulmonary capillary wedge pressure ≥25 mmHg, and resting PVR <3.5 WU who were randomized 1:1 to atrial shunt device or sham control. The primary outcome, a hierarchical composite of cardiovascular death, nonfatal ischemic stroke, recurrent HF events, and change in health status, was analyzed using the win ratio. Latent PVD was defined as PVR ≥1.74 WU (highest tertile) at peak exercise, measured prior to randomization. Results: Compared to patients without PVD (n=382), those with latent PVD (n=188) were older, had more atrial fibrillation and right heart dysfunction, and were more likely to have elevated LA pressure at rest. Shunt treatment was associated with worse outcomes in patients with PVD (win ratio 0.60, [95% CI 0.42, 0.86]; p=0.005) and signal of clinical benefit in patients without PVD (win ratio 1.31 [95% CI 1.02, 1.68]; p=0.038). Patients with larger RA volumes and men had worse outcomes with the device, and both groups were more likely to have pacemakers, HFmrEF, and increased LA volume. For patients without latent PVD or pacemaker (n=313, 50% of randomized patients), shunt treatment resulted in more robust signal of clinical benefit (win ratio 1.51 [95% CI 1.14, 2.00]; p=0.004). Conclusions: In patients with HFpEF/HFmrEF, the presence of latent PVD uncovered by invasive hemodynamic exercise testing identifies patients who may worsen with atrial shunt therapy, whereas those without latent PVD may benefit.