Leadless pacemakers: A review of current data and future directions.

Leadless pacemakers (LPs) have revolutionized the field of pacing by miniaturizing pacemakers and rendering them completelty intracardiac, hence reducing complications related to pacemaker pockets and transvenous leads. However, first generation LPs appear to be associated with a higher rate of myocardial perforation as compared to transvenous pacemakers (TV-PPM). Currently, LPs are predominantly designed to pace the right ventricle with no LPs that provide atrial or biventricular pacing. In this article, we review the available data on LPs while advocating for the need for a randomized controlled trial comparing LPs to TV-PPMs. In addition, we review the future directions of leadless devices.

Imaging for Predicting, Detecting, and Managing Complications After Transcatheter Aortic Valve Replacement.

The management of patients with valvular heart disease is increasingly reliant on multimodal cardiac imaging. In patients with severe aortic stenosis considered for transcatheter aortic valve replacement, careful pre-procedural planning with multimodal imaging is necessary to avoid and prevent complications during the procedure. During or immediately after the procedure, rapid echocardiographic assessment is important to assess the new valve's function and manage major complications. Echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging all share important roles in the post-procedural evaluation of abnormal transcatheter valve function. This review discusses the use of multimodal imaging for predicting, detecting, and managing complications after TAVR.

Pulmonary Venous Waveforms Predict Rehospitalization and Mortality After Percutaneous Mitral Valve Repair.

OBJECTIVES: In this study, the authors hypothesized that intraprocedural improvement of pulmonary venous (PV) waveforms are predictive of improved outcomes. In this report, they analyzed intraprocedural invasive and echocardiographic changes with respect to rehospitalization and mortality. BACKGROUND: The effects of hemodynamic changes during percutaneous mitral valve repair (PMVR) with MitraClip (Abbott Vascular, Santa Clara, California) are incompletely characterized. METHODS: The authors retrospectively reviewed records and intraprocedural transesophageal echocardiograms of 115 consecutive patients (age 76 ± 12 years) who underwent PMVR for mitral regurgitation (MR) from May 2013 to January 2017 at Emory University Hospital. They assessed intraprocedural PV waveforms for improvement in morphology, measured change in MR grade by semiquantitative methods, evaluated invasive changes in left atrial pressure (LAP) and V-wave, and compared with 30-day and 1-year rehospitalization and all-cause mortality. RESULTS: Ninety-three cases (80%) had PV waveforms before and after clip placement sufficient for analysis, of which 67 (73%) demonstrated intraprocedural improvement in PV morphology and 25 (27%) did not. At 24 months, 57 (85%) of those with PV improvement were living, compared with only 10 (40%) of those without improvement. Proportional hazards models demonstrated a significant survival advantage in those with PV improvement (hazard ratio [HR]: 0.28, 95% confidence interval [CI]: 0.08 to 0.93, p = 0.038). By multivariable analysis, PV improvement predicted reduced 1-year cardiac rehospitalization (odds ratio [OR]: 0.18, p = 0.044). Intraprocedural assessment of MR grade and invasive hemodynamics did not consistently predict mortality and rehospitalization. CONCLUSIONS: PV waveforms are important markers of procedural success after PMVR. Our data show intraprocedural PV waveforms may predict rehospitalization and mortality after PMVR. A larger, multicenter cohort will be important to clarify this relationship.

Cardiac events during treatment with proteasome inhibitor therapy for multiple myeloma.

BACKGROUND: Proteasome inhibitors (PI) bortezomib and carfilzomib are cornerstone therapies for multiple myeloma. Higher incidence of cardiac adverse events (CAEs) has been reported in patients receiving carfilzomib. However, risk factors for cardiac toxicity remain unclear. Our objective was to evaluate the incidence of CAEs associated with PI and recognize risk factors for developing events. METHODS: This was a descriptive analysis of 96 patients with multiple myeloma who received bortezomib (n = 44) or carfilzomib (n = 52). We compared the cumulative incidence of CAEs using a log rank test. Patient-related characteristics were assessed and multivariate analysis was used to identify risk factors for developing CAEs. RESULTS: PI-related CAEs occurred in 21 (22%) patients. Bortezomib-associated CAEs occurred in 7 (16%) patients while carfilzomib-associated cardiac events occurred in 14 (27%) patients. The cumulative incidence of CAEs was not significantly different between agents. Events occurred after a median of 67.5 days on PI therapy. Heart failure was the most prevalent event type. More patients receiving carfilzomib were monitored by a cardiologist. By multivariate analysis, a history of prior cardiac events and longer duration of PI therapy were identified as independent risk factors for developing CAEs. CONCLUSIONS: AEs were common in patients receiving PIs. Choice of PI did not impact the cumulative incidence of CAEs. Early involvement by a cardiologist in patients at high risk for CAEs may help to mitigate the frequency and severity of CAEs.

Three and Four Horizontal Muscle Surgery for Large Angle Exotropia.

PURPOSE: Surgery on two horizontal recti typically is most effective for angles less than 40 prism diopters (PD). The authors evaluate their experience operating on three or four rectus muscles for angles exceeding 40 PD. METHODS: Retrospective chart review of 47 patients who underwent a first surgical procedure for a large angle comitant exodeviation. Patients were observed for a minimum of 2 months. Success was defined as deviation ±10 PD. RESULTS: Median age was 48 years (range: 1 to 79 years). Thirty-four patients underwent three muscle surgery and 13 underwent four muscle surgery. Mean preoperative angles were 55 ± 9.8 and 72 ± 8.8 PD, respectively. Following three muscle surgery, rates of success, undercorrection, and overcorrection were 67%, 27%, and 7% at 2 months and 42%, 58%, and 0% at final follow-up (12 ± 8.7 months), respectively. Rates for four muscle surgery were 44%, 33%, and 22% at 2 months and 50%, 38%, and 13% at final follow-up (11 ± 12.2 months), respectively. Patients who were successfully aligned at 2 months had a mean preoperative angle of 55 PD, whereas those who were undercorrected had a mean preoperative angle of 67 PD (P = .009). Between 1 week and 2 months, 77% of patients experienced exotropic drift averaging 10 ± 9.1 PD. By final follow-up, 90% experienced exotropic drift averaging 15 ± 14.1 PD. Success rates for traditional and adjustable suture surgeries did not differ significantly. CONCLUSIONS: Three and four horizontal muscle surgeries are effective for correcting large angle exotropia. Higher preoperative deviations predisposed to undercorrection. Postoperative exotropic drift should be anticipated.

Decoupling of host-symbiont-phage coadaptations following transfer between insect species.

Transferring endosymbiotic bacteria between different host species can perturb the coordinated regulation of the host and bacterial genomes. Here we use the most common maternally transmitted bacteria, Wolbachia pipientis, to test the consequences of host genetic background on infection densities and the processes underlying those changes in the parasitoid wasp genus Nasonia. Introgressing the genome of Nasonia giraulti into the infected cytoplasm of N. vitripennis causes a two-order-of-magnitude increase in bacterial loads in adults and a proliferation of the infection to somatic tissues. The host effect on W. pipientis distribution and densities is associated with a twofold decrease in densities of the temperate phage WO-B. Returning the bacteria from the new host species back to the resident host species restores the bacteria and phage to their native densities. To our knowledge, this is the first study to report a host-microbe genetic interaction that affects the densities of both W. pipientis and bacteriophage WO-B. The consequences of the increased bacterial density include a reduction in fecundity, an increase in levels of cytoplasmic incompatibility (CI), and unexpectedly, male-to-female transfer of the bacteria to uninfected females and an increased acceptance of densely infected females to interspecific mates. While paternal inheritance of the W. pipientis was not observed, the high incidence of male-to-female transfer in the introgressed background raises the possibility that paternal transmission could be more likely in hybrids where paternal leakage of other cytoplasmic elements is also known to occur. Taken together, these results establish a major change in W. pipientis densities and tissue tropism between closely related species and support a model in which phage WO, Wolbachia, and arthropods form a tripartite symbiotic association in which all three are integral to understanding the biology of this widespread endosymbiosis.

A Comparative Study of Two New Structure Types. Synthesis and Structural and Electronic Characterization of K(RE)P(2)Se(6) (RE = Y, La, Ce, Pr, Gd).

Two polytypes of potassium rare-earth-metal hexaselenodiphosphates(IV), K(RE)P(2)Se(6) (RE = Y, La, Ce, Pr, Gd), have been synthesized from the stoichiometric reaction of RE, P, Se, and K(2)Se(4) at 750 degrees C. Both single-crystal and powder X-ray diffraction analyses showed that the structures of these polytypes vary with the size of the rare earth metals. For the smaller rare-earth metals, Y and Gd, K(RE)P(2)Se(6) crystallized in the orthorhombic space group P2(1)2(1)2(1). The yttrium compound was studied by single-crystal X-ray diffraction with the cell parameters a = 6.7366(5) Å, b = 7.4286(6) Å, c = 21.603(2) Å, and Z = 4. This structure type comprises a layered, square network of yttrium atoms that are bound to four distinct [P(2)Se(6)](4)(-) units through selenium bonding. Each [P(2)Se(6)](4)(-) unit possesses a Se atom that is not bound to any Y atom but is pointing out into the interlayer spacing, into an environment of potassium cations. For larger rare-earth metals, La, Ce, and Pr, K(RE)P(2)Se(6) crystallized in a second, monoclinic polytype, the structure of which has been published. Both of these two different polytypes can be related to each other and several other isoelectronic chalcophosphate structures based on a Parthé valence electron concentration analysis. These structures include Ag(4)P(2)S(6), K(2)FeP(2)S(6), and the hexagonal M(II)PS(3) structure types. The magnetic susceptibilities of the title compounds have been studied, and the behavior can been explained based on a simple set of unpaired f-electrons. The diffuse reflectance spectroscopy also showed that these yellow plates are moderately wide band gap ( approximately 2.75 eV) semiconductors.