Abstract
Aims
This study aims to improve risk stratification for primary prevention implantable cardioverter defibrillator (ICD) implantation by developing a new mutation-specific prediction model ...for malignant ventricular arrhythmia (VA) in phospholamban (PLN) p.Arg14del mutation carriers. The proposed model is compared to an existing PLN risk model.
Methods and results
Data were collected from PLN p.Arg14del mutation carriers with no history of malignant VA at baseline, identified between 2009 and 2020. Malignant VA was defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. A prediction model was developed using Cox regression. The study cohort consisted of 679 PLN p.Arg14del mutation carriers, with a minority of index patients (17%) and male sex (43%), and a median age of 42 years interquartile range (IQR) 27–55. During a median follow-up of 4.3 years (IQR 1.7–7.4), 72 (10.6%) carriers experienced malignant VA. Significant predictors were left ventricular ejection fraction, premature ventricular contraction count/24 h, amount of negative T waves, and presence of low-voltage electrocardiogram. The multivariable model had an excellent discriminative ability {C-statistic 0.83 95% confidence interval (CI) 0.78–0.88}. Applying the existing PLN risk model to the complete cohort yielded a C-statistic of 0.68 (95% CI 0.61–0.75).
Conclusion
This new mutation-specific prediction model for individual VA risk in PLN p.Arg14del mutation carriers is superior to the existing PLN risk model, suggesting that risk prediction using mutation-specific phenotypic features can improve accuracy compared to a more generic approach.
Graphical Abstract
Malignant VA risk prediction in PLN p.Arg14del carriers. With the mutation specific risk factors low and high risk groups can be identified. PLN, Phospholamban; VA, Ventricular arrhythmia.
Age- and gender-related differences in QTc-interval are most likely the result of changes in sex-specific hormones. Although the exact mechanisms and pathophysiology of sex hormones on the ...QTc-interval are not known, testosterone appears to shorten the QTc-interval. In females, however, there is a more complex interaction between progesterone and estrogen. In patients with an impaired repolarization, such as long-QT syndrome (LQTS), the effect of these sex hormones on the QTc-interval is more pronounced with a differing sensitivity between the LQTS genotypes.
Abstract
We develop a resource theory of symmetric distinguishability, the fundamental objects of which are elementary quantum information sources, i.e. sources that emit one of two possible quantum ...states with given prior probabilities. Such a source can be represented by a classical-quantum state of a composite system
XA
, corresponding to an ensemble of two quantum states, with
X
being classical and
A
being quantum. We study the resource theory for two different classes of free operations: (i) CPTP
A
, which consists of quantum channels acting only on
A
, and (ii) conditional doubly stochastic maps acting on
XA
. We introduce the notion of symmetric distinguishability of an elementary source and prove that it is a monotone under both these classes of free operations. We study the tasks of distillation and dilution of symmetric distinguishability, both in the one-shot and asymptotic regimes. We prove that in the asymptotic regime, the optimal rate of converting one elementary source to another is equal to the ratio of their quantum Chernoff divergences, under both these classes of free operations. This imparts a new operational interpretation to the quantum Chernoff divergence. We also obtain interesting operational interpretations of the Thompson metric, in the context of the dilution of symmetric distinguishability.
This paper develops the resource theory of asymmetric distinguishability for quantum channels, generalizing the related resource theory for states Matsumoto, arXiv:1010.1030, Wang and Wilde, Phys. ...Rev. Research 1, 033170 (2019)10.1103/PhysRevResearch.1.033170. The key constituents of the channel resource theory are quantum channel boxes, consisting of a pair of quantum channels, which can be manipulated for free by means of an arbitrary quantum superchannel (the most general physical transformation of a quantum channel). One main question of the resource theory is the approximate channel box transformation problem, in which the goal is to transform an initial channel box (or boxes) to a final channel box (or boxes), while allowing for an asymmetric error in the transformation. The channel resource theory is richer than its counterpart for states because there is a wider variety of ways in which this question can be framed, either in the one-shot or n-shot regimes, with the latter having parallel and sequential variants. As in our prior work Wang and Wilde, Phys. Rev. Research 1, 033170 (2019)10.1103/PhysRevResearch.1.033170, we consider two special cases of the general channel box transformation problem, known as distinguishability distillation and dilution. For the one-shot case, we find that the optimal values of the various tasks are equal to the nonsmooth or smooth channel min- or max-relative entropies, thus endowing all of these quantities with operational interpretations. In the asymptotic sequential setting, we prove that the exact distinguishability cost is equal to the channel max-relative entropy and the distillable distinguishability is equal to the amortized channel relative entropy of Berta, Hirche, Kaur, and Wilde, arXiv:1808.01498. This latter result can also be understood as a solution to Stein's lemma for quantum channels in the sequential setting. Finally, the theory simplifies significantly for environment-seizable and classical-quantum channel boxes.
We construct new polar coding schemes for the transmission of quantum or private classical information over arbitrary quantum channels. In the former case, our coding scheme achieves the symmetric ...coherent information, and in the latter, the symmetric private information. Both schemes are built from a polar coding construction capable of transmitting classical information over a quantum channel. Appropriately merging two such classical-quantum schemes, one for transmitting amplitude information and the other for transmitting phase, leads to the new private and quantum coding schemes, similar to the construction for Pauli and erasure channels of Renes et al. The encoding is entirely similar to the classical case, and thus efficient. The decoding can also be performed by successive cancellation, as in the classical case, but no efficient successive cancellation scheme is yet known for arbitrary quantum channels. An efficient code construction is unfortunately still unknown. Generally, our two coding schemes require entanglement or secret-key assistance, respectively, but we extend two known conditions under which the needed assistance rate vanishes. Finally, although our results are formulated for qubit channels, we show how the scheme can be extended to multiple qubits. This then demonstrates a near-explicit coding method for realizing one of the most striking phenomena in quantum information theory: the superactivation effect, whereby two quantum channels, which individually have zero quantum capacity can have a nonzero quantum capacity when used together.
This paper establishes several converse bounds on the private transmission capabilities of a quantum channel. The main conceptual development builds firmly on the notion of a private state, which is ...a powerful, uniquely quantum method for simplifying the tripartite picture of privacy involving local operations and public classical communication to a bipartite picture of quantum privacy involving local operations and classical communication. This approach has previously led to some of the strongest upper bounds on secret key rates, including the squashed entanglement and the relative entropy of entanglement. Here, we use this approach along with a "privacy test" to establish a general meta-converse bound for private communication, which has a number of applications. The meta-converse allows for proving that any quantum channel's relative entropy of entanglement is a strong converse rate for private communication. For covariant channels, the meta-converse also leads to second-order expansions of relative entropy of entanglement bounds for private communication rates. For such channels, the bounds also apply to the private communication setting in which the sender and the receiver are assisted by unlimited public classical communication, and as such, they are relevant for establishing various converse bounds for quantum key distribution protocols conducted over these channels. We find precise characterizations for several channels of interest and apply the methods to establish converse bounds on the private transmission capabilities of all phase-insensitive bosonic channels.
Objectives The aim of this study was to determine the availability of quinidine throughout the world. Background Quinidine is the only oral medication that is effective for preventing ...life-threatening ventricular arrhythmias due to Brugada syndrome and idiopathic ventricular fibrillation. However, because of its low price and restricted indication, this medication is not marketed in many countries. Methods We conducted a survey of the availability of quinidine by contacting professional medical societies and arrhythmia specialists worldwide. Physicians were e-mailed questionnaires requesting information concerning the quinidine preparation available at their hospital. We also requested information concerning cases of adverse arrhythmic events resulting from unavailability of quinidine. Results A total of 273 physicians from 131 countries provided information regarding the availability of quinidine. Quinidine was readily available in 19 countries (14%), not accessible in 99 countries (76%), and available only through specific regulatory processes that require 4 to 90 days for completion in 13 countries (10%). We were able to gather information concerning 22 patients who had serious arrhythmias probably related (10 cases) or possibility related (12 cases) to the absence of quinidine, including 2 fatalities possibly attributable to the unavailability of quinidine. Conclusions The lack of accessibility of quinidine is a serious medical hazard at the global level.
A bis(amino)cyclopropenylidene (BAC) catalyzed aza-benzoin reaction between aldehydes and phosphinoyl imines has been developed. The reaction is general with a wide range of aromatic aldehydes and ...aromatic imines. The reaction displays excellent chemoselectivity favoring aza-benzoin products over homobenzoin products.
Back to BACs: In the pursuit of novel carbene organocatalysts, bis(amino)cyclopropenylidenes (BACs) were explored as alternatives to N‐heterocyclic carbenes. They were effective in catalyzing the ...Stetter reaction, and displayed unique advantages over the commonly used thiazolylidenes and triazolylidenes. They also mediated extended umpolung reactions of enals. In addition, chiral analogues can be accessed readily for applications in enantioselective catalysis.
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