Chemotherapy and Radiation-Associated Cardiac Autonomic Dysfunction.

PURPOSE OF REVIEW: Cardiovascular autonomic dysfunction (AD) among cancer survivors is increasingly being recognized. However, the mechanisms and incidence are poorly understood. In this review, the clinical features, diagnostic modalities, proposed mechanisms, and currently available treatments of cardiovascular AD in cancer survivors are described. RECENT FINDINGS: Much of our current understanding of cardiovascular AD is based on disease states such as diabetes, multisystem atrophy, and Parkinson's disease. Several non-invasive tests, measurements, and scoring systems have been developed as surrogates for autonomic function, with some even demonstrating associations with all-cause mortality. The mechanism of cardiovascular AD specifically in the cancer population, however, has not been directly studied. The etiology of cardiovascular AD in cancer survivors is likely multifactorial, and proposed mechanisms include direct nerve damage by chemoradiation, the pro-inflammatory state associated with malignancy, and paraneoplastic syndromes. It may also be that cardiovascular AD is an early marker of global cardiomyopathy rather than its own condition. Current pharmacologic options for cardiovascular AD are extrapolated from how it has been treated in other disease processes, and these agents have not been studied in the cancer population or compared head-to-head. Cardiovascular AD in cancer survivors can cause significant debilitation and may be associated with all-cause mortality. Current diagnostic modalities have several limitations, such as standardization and validity. However, given the nonspecific nature of cardiovascular AD, these tools provide an objective marker for diagnosis and tracking treatment response. While the mechanism of cardiovascular AD in cancer survivors has not been directly studied, it may be useful to evoke mechanisms of cardiovascular AD in other disease states such as diabetes, Parkinson's disease, and multisystem atrophy in addition to identifying unique conditions associated with malignancy like a pro-inflammatory state. Until further studies are performed, management of cardiovascular AD as seen in other disease states may serve as a guide for symptom management in cancer survivors.

Physiological mechanisms of QRS narrowing in bundle branch block patients undergoing permanent His bundle pacing.

His bundle pacing is increasingly used to avoid chronic right ventricular pacing, and electrically resynchronize ventricular activation by narrowing or normalizing the QRS interval in left and right bundle branch block. The mechanisms by which this occurs remain poorly understood. In this review, the proposed mechanisms and evidence supporting them are discussed. Also discussed are aspects of mechanisms that are not completely supported by the evidence. We also review the differences and physiological bases for direct vs. indirect His bundle capture, and the physiological mechanisms for QRS narrowing vs. normalization following His bundle pacing.

Temporal trends and outcomes of peripheral artery disease revascularization and amputation among the HIV population.

OBJECTIVE: With antiretroviral therapy, people with HIV (PWH) are developing age-related diseases, including peripheral arterial disease (PAD). This study examined frequency and outcomes of peripheral vascular intervention (PVI) and primary amputation in PWH. DESIGN: We used the National Inpatient Sample (NIS) database to examine demographics, comorbidities, and temporal trends among PVI and primary amputation admissions by HIV status from 2012 to 2018. METHODS: Inverse probability of treatment weighting was used to calculate adjusted odds of in-hospital death and amputation. Cost of hospitalization and length of stay were compared by HIV status and revascularization approach. RESULTS: Of the 347 824 hospitalizations for PVI/amputation, 0.6% were PWH, which was stable over time. PWH had more renal and hepatic disease, whereas uninfected individuals had more traditional PAD risk factors. 55.2% of HIV+ admissions were endovascular compared with 49.3% in HIV- admissions, and 28.9% of the HIV+ admissions were elective compared with 42.1% among HIV-. HIV status did not impact amputation following PVI. In-hospital death was similar between groups following PVI or primary amputation. PWH had lower costs of hospitalization and a trend towards shorter hospital stays. CONCLUSION: Although PWH are developing more age-related chronic illnesses, the number of PAD-associated procedures has remained flat. Despite being younger with fewer traditional PAD risk factors, PWH had higher rates of unplanned PVI admissions and endovascular revascularization but similar in-hospital outcomes. These findings suggest PWH have different risk factors for PAD and are likely underdiagnosed and undertreated, whereas those who are treated have similar outcomes to the general population.

Usefulness of His Bundle Pacing to Achieve Electrical Resynchronization in Patients With Complete Left Bundle Branch Block and the Relation Between Native QRS Axis, Duration, and Normalization.

His Bundle pacing (HBP) restores electrical synchronization in left bundle branch block (LBBB); however, the underlying mechanisms are poorly understood. We examined the relation between native QRS axis in LBBB, a potential indicator of the site of block, and QRS normalization in patients with LBBB. Data from patients (n = 41) undergoing HBP at 3 sites were studied (68 ± 13 years, 13 women). Study criteria included strictly defined complete LBBB and successful implantation of a permanent HBP lead. Preprocedure and postprocedure electrocardiograms were reviewed independently by 2 blinded readers. QRS axis and duration were measured to the nearest 10° and 10 ms, respectively. QRS narrowing or normalization was the primary end point. Of 29 patients meeting study criteria, 9 had frontal plane QRS axes between -60° and -80°, 10 from -40° to 0°, and 10 from +1° to +90°. QRS narrowing occurred in 24 patients (83%, 44 ± 34 ms, p <0.05). Percent QRS narrowing by axis were 26 ± 19%, 29 ± 25%, and 28 ± 23%, respectively. No correlation between prepacing QRS axis and postpacing narrowing was identified (r(2) = 0.001, p = 0.9). In patients with or without QRS normalization after HBP, mean QRS duration was 155 ± 21 vs 171 ± 8 ms, respectively, p = 0.014. HBP induces significant QRS narrowing in most patients and normalization in patients with shorter baseline QRS duration. In conclusion, the lack of correlation between native QRS axis and narrowing suggests that proximal His-Purkinje block causes most cases of LBBB, or that additional mechanisms underlie HBP efficacy. Further studies are needed to better understand how to predict those patients in whom HBP will normalize LBBB.

Impact of decision aids in a sustained implementation at a breast care center.

OBJECTIVE: We examined the reach and impact of five decision aids (DAs) routinely distributed to breast cancer patients as part of a shared decision making demonstration project. METHODS: From 2005 to 2008, we surveyed patients' change in knowledge and decisional conflict (DC) before and after their review of DAs. Using bivariate tests, we identified significant predictors of change in knowledge or decisional conflict and entered significant predictors into a multivariate regression model. RESULTS: We distributed 1553 DAs to 1098 patients and received 549 completed surveys. The DAs were associated with increased knowledge and decreased DC. For knowledge, significant predictors of above-average change included: lower baseline knowledge and viewing the surgery decision aid. For decisional conflict, significant predictors of above-average change included: higher decisional conflict; viewing any of the early-stage cancer DAs; and Hispanic ethnicity. CONCLUSIONS: DAs used in routine care were associated with significant knowledge gains and reductions in decisional conflict. Some subsets of patients (those reporting low baseline knowledge, high DC, or Hispanic ethnicity) may benefit more than others. PRACTICE IMPLICATIONS: Breast cancer patients benefit overall from routine distribution of DAs. Our exploratory findings may be useful in generating hypotheses to identify target populations who would most benefit from reviewing DAs.