Artificial intelligence-assisted automated heart failure detection and classification from electronic health records.

AIMS: Electronic health records (EHR) linked to Digital Imaging and Communications in Medicine (DICOM), biological specimens, and deep learning (DL) algorithms could potentially improve patient care through automated case detection and surveillance. We hypothesized that by applying keyword searches to routinely stored EHR, in conjunction with AI-powered automated reading of DICOM echocardiography images and analysing biomarkers from routinely stored plasma samples, we were able to identify heart failure (HF) patients. METHODS AND RESULTS: We used EHR data between 1993 and 2021 from Tayside and Fife (~20% of the Scottish population). We implemented a keyword search strategy complemented by filtering based on International Classification of Diseases (ICD) codes and prescription data to EHR data set. We then applied DL for the automated interpretation of echocardiographic DICOM images. These methods were then integrated with the analysis of routinely stored plasma samples to identify and categorize patients into HF with reduced ejection fraction (HFrEF), HF with preserved ejection fraction (HFpEF), and controls without HF. The final diagnosis was verified through a manual review of medical records, measured natriuretic peptides in stored blood samples, and by comparing clinical outcomes among groups. In our study, we selected the patient cohort through an algorithmic workflow. This process started with 60 850 EHR data and resulted in a final cohort of 578 patients, divided into 186 controls, 236 with HFpEF, and 156 with HFrEF, after excluding individuals with mismatched data or significant valvular heart disease. The analysis of baseline characteristics revealed that compared with controls, patients with HFrEF and HFpEF were generally older, had higher BMI, and showed a greater prevalence of co-morbidities such as diabetes, COPD, and CKD. Echocardiographic analysis, enhanced by DL, provided high coverage, and detailed insights into cardiac function, showing significant differences in parameters such as left ventricular diameter, ejection fraction, and myocardial strain among the groups. Clinical outcomes highlighted a higher risk of hospitalization and mortality for HF patients compared with controls, with particularly elevated risk ratios for both HFrEF and HFpEF groups. The concordance between the algorithmic selection of patients and manual validation demonstrated high accuracy, supporting the effectiveness of our approach in identifying and classifying HF subtypes, which could significantly impact future HF diagnosis and management strategies. CONCLUSIONS: Our study highlights the feasibility of combining keyword searches in EHR, DL automated echocardiographic interpretation, and biobank resources to identify HF subtypes.

2024 Australia-New Zealand Expert Consensus Statement on Cardiac Amyloidosis.

Over the past 5 years, early diagnosis of and new treatments for cardiac amyloidosis (CA) have emerged that hold promise for early intervention. These include non-invasive diagnostic tests and disease modifying therapies. Recently, CA has been one of the first types of cardiomyopathy to be treated with gene editing techniques. Although these therapies are not yet widely available to patients in Australia and New Zealand, this may change in the near future. Given the rapid pace with which this field is evolving, it is important to view these advances within the Australian and New Zealand context. This Consensus Statement aims to update the Australian and New Zealand general physician and cardiologist with regards to the diagnosis, investigations, and management of CA.

HeartMate 3 implantation with an emphasis on the biventricular configuration.

OBJECTIVES: Right ventricular failure following implantation of a durable left ventricular assist device (LVAD) is a major driver of mortality. Reported survival following biventricular (BiVAD) or total artificial heart (TAH) implantation remains substantially inferior to LVAD alone. We report our outcomes with LVAD and BiVAD HeartMate 3 (HM3). METHODS: Consecutive patients undergoing implantation of an HM3 LVAD between November 2014 and December 2021, at The Alfred, Australia were included in the study. Comparison was made between the BiVAD and LVAD alone groups. RESULTS: A total of 86 patients, 65 patients with LVAD alone and 21 in a BiVAD configuration underwent implantation. The median age of the LVAD and BiVAD groups was 56 years (Interquartile range 46-62) and 49 years (Interquartile range 37-55), respectively. By 4 years after implantation, 54% of LVAD patients and 43% of BiVAD patients had undergone cardiac transplantation. The incidence of stroke in the entire experience was 3.5% and pump thrombosis 5% (all in the RVAD). There were 14 deaths in the LVAD group and 1 in the BiVAD group. The actuarial survival for LVAD patients at 1 year was 85% and BiVAD patients at 1 year was 95%. CONCLUSIONS: The application of HM 3 BiVAD support in selected patients appears to offer a satisfactory solution to patients requiring biventricular support.

Hypothermic oxygenated perfusion (HOPE) safely and effectively extends acceptable donor heart preservation times: Results of the Australian and New Zealand trial.

BACKGROUND: Cold static storage preservation of donor hearts for periods longer than 4 hours increases the risk of primary graft dysfunction (PGD). The aim of the study was to determine if hypothermic oxygenated perfusion (HOPE) could safely prolong the preservation time of donor hearts. METHODS: We conducted a nonrandomized, single arm, multicenter investigation of the effect of HOPE using the XVIVO Heart Preservation System on donor hearts with a projected preservation time of 6 to 8 hours on 30-day recipient survival and allograft function post-transplant. Each center completed 1 or 2 short preservation time followed by long preservation time cases. PGD was classified as occurring in the first 24 hours after transplantation or secondary graft dysfunction (SGD) occurring at any time with a clearly defined cause. Trial survival was compared with a comparator group based on data from the International Society of Heart and Lung Transplantation (ISHLT) Registry. RESULTS: We performed heart transplants using 7 short and 29 long preservation time donor hearts placed on the HOPE system. The mean preservation time for the long preservation time cases was 414 minutes, the longest being 8 hours and 47 minutes. There was 100% survival at 30 days. One long preservation time recipient developed PGD, and 1 developed SGD. One short preservation time patient developed SGD. Thirty day survival was superior to the ISHLT comparator group despite substantially longer preservation times in the trial patients. CONCLUSIONS: HOPE provides effective preservation out to preservation times of nearly 9 hours allowing retrieval from remote geographic locations.

Long term follow up and outcomes of Covid-19 vaccine associated myocarditis in Victoria, Australia: A clinical surveillance study.

BACKGROUND: Myocarditis and myopericarditis are well described adverse events of special interest (AESI) following COVID-19 vaccinations. Although reports are reassuring regarding initial clinical outcomes, information about longer term outcomes remains limited. We aimed to further this knowledge and report outcomes to 6 months post diagnosis from a single population cohort. METHODS: Reports of myocarditis following COVID-19 vaccination were followed up by SAEFVIC (Surveillance of Adverse Events Following Vaccination in the Community), the state-wide vaccine safety service for Victoria, Australia. Confirmed myocarditis cases (Brighton Collaboration Criteria levels 1-3) were followed up via surveys at 1, 3 and 6 months post symptom onset. Responses received between 22 February 2021 and 30 September 2022 were analysed. RESULTS: 87.5 % (N = 182) of eligible participants completed at least 1 survey report. 377 reports were analysed. 76.9 % of completed reports were from male patients. The median age of patients was 21 years [IQR: 16 to 32]. 54.8 % (n = 74) of survey reports at 6 months, reported ongoing symptoms. At all follow-up time points, females were significantly more likely to have ongoing symptoms. At 6 months, 51.9 % of male respondents reported symptom resolution compared to 22.6 % of female patients (p = 0.002). Females were also more likely to continue medication and have ongoing exercise restrictions. However, males were significantly more likely to have higher initial peak troponin results and abnormal initial cardiac imaging investigations. CONCLUSIONS: There appears to be a significant proportion of patients who experience ongoing symptoms to 6 months post onset amongst patients that experience these AESI. Male patients were more likely to report earlier and more complete symptom recovery, despite significantly higher average initial peak troponin. This difference in phenotypic presentation in females compared to males warrants further investigation and there is a need for longer term follow up data.

Use of Imaging-guided Decongestion for Reducing Heart Failure Readmission and Death in High-risk Patients: A Multi-site Randomized Trial of a Nurse-led Strategy at the Point of Care.

BACKGROUND: Nurse-led disease management programs (DMPs) decrease readmission after acute decompensated heart failure (HF). We sought whether readmissions could be further reduced by lung ultrasound (LUS)-guided decongestion before discharge and during DMP. METHODS AND RESULTS: Of 290 patients hospitalized with acute decompensated HF, 122 at high risk for readmission or mortality were randomized to receive usual care (UC) (n = 64) or UC plus intervention (DMP-Plus) (n = 58), comprising LUS-guided management before discharge and during at-home follow-up. Residual congestion was identified by ≥10 B-lines detected in 8 lung zones. The outcomes included a composite of readmission and/or mortality at 30 and 90 days, and 90-day HF readmission. Residual congestion was detected equally among the patient groups. The 30-day composite outcome occurred in 28% DMP-plus patients and 22% UC patients (odd ratio [OR], 1.36; 95% confidence interval [CI], 0.59-3.1; P = .5) and the 90-day HF readmission outcome occurred in 22% and 31%, respectively (odds ratio, 0.63; 95% CI, 0.28-1.43; P = .3). Residual congestion, identified at predischarge LUS examination in high-risk patients, was associated with early (<14-day) HF readmission (relative risk, 1.19; 95% CI, 1.06-1.32; P = .002) and multiple (≥2) readmissions over 90 days of follow-up (relative risk, 1.09; 95% CI, 1.01-1.16; P = .012), independent of demographics and comorbidities. CONCLUSIONS: Readmission in patients with incomplete decongestion before discharge occurs within the first 2 weeks. However, our DMP-plus strategy did not improve the primary outcome.

Diagnostic Sensitivity of Unenhanced CT for Cerebral Venous Thrombosis: Can Clot Density Measurement Replace CT Venogram?

Objectives Cerebral venous sinus thrombosis is an important cause of stroke in young adults. Noncontrast-enhanced CT head (NECT) is almost always the first investigation. Our objectives were as follows: 1. How accurately does venous sinus density on NECT predict the presence of clot on CT venogram (CTV)? 2. Whether repeated measurements changed the confidence? 3. How many venous sinus thrombus would be missed if we do not do a CTV? 4. Can clot density measurement replace CTV? Methods Multicenter case-control study was designed with data from seven hospitals. Inclusion criteria: all CT and magnetic resonance imaging venograms with a prior NECT, performed between 1.1.2018 and 31.12.2018 (12 months), were included. Hounsfield unit (HU) values were calculated at the site of highest density on the NECT. Logistic regression analysis was performed using STATA. Result Two-hundred seventy-seven cases met the criteria with 33 positive cerebral venous thrombosis (density on NECT 60-92 HU) and 244 negative examinations (density on NECT 31-68 HU). Area under the curve for average clot density on NECT was 0.9984. Conclusion We found a strong relationship between sinus density on NECT and outcome of CTV. Repeating density measurements did not add any predictive value or changed outcome. Advances in Knowledge Density 70 HU or higher on NECT always resulted in a positive CTV but would miss a fifth of the positives. Cutoff at 60 HU would not miss any but result in significant false positives. An efficient option could be to limit CTV to sinus densities 60 to 70 HU only. However, a larger study would be required for such change in practice.

Brain insulin signaling suppresses lipolysis in the absence of peripheral insulin receptors and requires the MAPK pathway.

OBJECTIVES: Insulin's ability to counterbalance catecholamine-induced lipolysis defines insulin action in adipose tissue. Insulin suppresses lipolysis directly at the level of the adipocyte and indirectly through signaling in the brain. Here, we further characterized the role of brain insulin signaling in regulating lipolysis and defined the intracellular insulin signaling pathway required for brain insulin to suppress lipolysis. METHODS: We used hyperinsulinemic clamp studies coupled with tracer dilution techniques to assess insulin's ability to suppress lipolysis in two different mouse models with inducible insulin receptor depletion in all tissues (IRΔWB) or restricted to peripheral tissues excluding the brain (IRΔPER). To identify the underlying signaling pathway required for brain insulin to inhibit lipolysis, we continuously infused insulin +/- a PI3K or MAPK inhibitor into the mediobasal hypothalamus of male Sprague Dawley rats and assessed lipolysis during clamps. RESULTS: Genetic insulin receptor deletion induced marked hyperglycemia and insulin resistance in both IRΔPER and IRΔWB mice. However, the ability of insulin to suppress lipolysis was largely preserved in IRΔPER, but completely obliterated in IRΔWB mice indicating that insulin is still able to suppress lipolysis as long as brain insulin receptors are present. Blocking the MAPK, but not the PI3K pathway impaired the inhibition of lipolysis by brain insulin signaling. CONCLUSION: Brain insulin is required for insulin to suppress adipose tissue lipolysis and depends on intact hypothalamic MAPK signaling.

UpStreAm doxycycline in ST-eLeVation myocArdial infarction: targetinG infarct hEaling and ModulatIon (SALVAGE-MI trial).

AIMS: Experimental studies demonstrate protective effects of doxycycline on myocardial ischaemia-reperfusion injury. The trial investigated whether doxycycline administered prior to reperfusion in patients presenting with ST-elevation myocardial infarction (STEMI) reduces infarct size (IS) and ameliorates adverse left ventricular (LV) remodelling. METHODS AND RESULTS: In this randomized, double-blind, placebo-controlled trial, patients presenting with STEMI undergoing primary percutaneous coronary intervention (PPCI) were randomized to either intravenous doxycycline or placebo prior to reperfusion followed by 7 days of oral doxycycline or placebo. The primary outcome was final IS adjusted for area-at-risk (fIS/AAR) measured on two cardiac magnetic resonance scans ∼6 months apart. Of 103 participants, 50 were randomized to doxycycline and 53 to placebo and were matched for age (59 ± 12 vs. 60 ± 10 years), male sex (92% vs. 79%), diabetes mellitus (26% vs. 11%) and left anterior descending artery occlusion (50% vs. 49%), all P > 0.05. Patients treated with doxycycline had a trend for larger fIS/AAR [0.79 (0.5-0.9) vs. 0.61 (0.47-0.76), P = 0.06], larger fIS at 6 months [18.8% (12-26) vs. 13.6% (11-21), P = 0.08], but similar acute IS [21.7% (17-34) vs. 19.4% (14-27), P = 0.19] and AAR [26% (20-36) vs. 24.7% (16-31), P = 0.22] compared with placebo. Doxycycline did not ameliorate adverse LV remodelling [%Δend-diastolic volume index, 1.1% (-3.8-8.4) vs. -1.34% (-6.1-5.8), P = 0.42] and was independently associated with larger fIS (regression coefficient = 0.175, P = 0.03). CONCLUSION: Doxycycline prior to PPCI neither reduced IS acutely or at six months nor attenuated adverse LV remodelling. These data raise safety concerns regarding doxycycline use in STEMI for infarct modulation and healing.

Current approaches to the diagnosis and management of amyloidosis.

Amyloidosis is a collection of diseases caused by the misfolding of proteins that aggregate into insoluble amyloid fibrils and deposit in tissues. While these fibrils may aggregate to form insignificant localised deposits, they can also accumulate in multiple organs to the extent that amyloidosis can be an immediately life-threatening disease, requiring urgent treatment. Recent advances in diagnostic techniques and therapies are dramatically changing the disease landscape and patient prognosis. Delays in diagnosis and treatment remain the greatest challenge, necessitating physician awareness of the common clinical presentations that suggest amyloidosis. The most common types are transthyretin (ATTR) amyloidosis followed by immunoglobulin light-chain (AL) amyloidosis. While systemic AL amyloidosis was previously considered a death sentence with no effective therapies, significant improvement in patient survival has occurred over the past 2 decades, driven by greater understanding of the disease process, risk-adapted adoption of myeloma therapies such as proteosome inhibitors (bortezomib) and monoclonal antibodies (daratumumab) and improved supportive care. ATTR amyloidosis is an underdiagnosed cause of heart failure. Technetium scintigraphy has made noninvasive diagnosis much easier, and ATTR is now recognised as the most common type of amyloidosis because of the increased identification of age-related ATTR. There are emerging ATTR treatments that slow disease progression, decrease patient hospitalisations and improve patient quality of life and survival. This review aims to update physicians on recent developments in amyloidosis diagnosis and management and to provide a diagnostic and treatment framework to improve the management of patients with all forms of amyloidosis.

Type-2 Diabetes and the Clinical Importance of Exaggerated Exercise Blood Pressure.

BACKGROUND: Exaggerated exercise blood pressure (EEBP) during clinical exercise testing is associated with poor blood pressure (BP) control and cardiovascular disease (CVD). Type-2 diabetes (T2DM) is thought to be associated with increased prevalence of EEBP, but this has never been definitively determined and was the aim of this study. METHODS: Clinical exercise test records were analyzed from 13 268 people (aged 53±13 years, 59% male) who completed the Bruce treadmill protocol (stages 1-4, and peak) at 4 Australian public hospitals. Records (including BP) were linked to administrative health datasets (hospital and emergency admissions) to define clinical characteristics and classify T2DM (n=1199) versus no T2DM (n=12 069). EEBP was defined as systolic BP ≥90th percentile at each test stage. Exercise BP was regressed on T2DM history and adjusted for CVD and risk factors. RESULTS: Prevalence of EEBP (age, sex, preexercise BP, hypertension history, CVD history and aerobic capacity adjusted) was 12% to 51% greater in T2DM versus no T2DM (prevalence ratio [95% CI], stage 1, 1.12 [1.02-1.24]; stage 2, 1.51 [1.41-1.61]; stage 3, 1.25 [1.10-1.42]; peak, 1.18 [1.09-1.29]). At stages 1 to 3, 8.6% to 15.8% (4.8%-9.7% T2DM versus 3.5% to 6.1% no-T2DM) of people with 'normal' preexercise BP (<140/90 mm Hg) were identified with EEBP. Exercise systolic BP relative to aerobic capacity (stages 1-4 and peak) was higher in T2DM with adjustment for all CVD risk factors. CONCLUSIONS: People with T2DM have higher prevalence of EEBP and exercise systolic BP independent of CVD and many of its known risk factors. Clinicians supervising exercise testing should be alerted to increased likelihood of EEBP and thus poor BP control warranting follow-up care in people with T2DM.

Spontaneous Coronary Artery Dissection in an Orthotopic Heart Transplant Recipient.

We present the case of acute myocardial infarction secondary to spontaneous coronary artery dissection in a patient 2 weeks post orthotopic heart transplantation. (Level of Difficulty: Advanced.).

Incidence and Predictors of Eosinophilic Myocardial Hypersensitivity in Patients Receiving Home Dobutamine.

ABSTRACT: We sought to examine incidence and predictors of eosinophilic myocardial hypersensitivity (EMH) in a cohort of patients in the home inotrope program of a quaternary cardiac transplant center. Patients on home inotropes with progression to heart transplantation or ventricular assist device (VAD) between January 2000 and May 2020 were included. EMH was diagnosed by the presence of an interstitial predominate eosinophilic infiltrate within the myocardium by experienced cardiac pathologists. From a cohort of 74 patients, 58% (43) were on dobutamine and 42% (31) were on milrinone. Dobutamine was associated with EMH incidence of 14% (6/43), with zero cases in the milrinone cohort. Mean age was 52 ± 12 years, 22% were female. More than half (62%) were nonischemic dilated cardiomyopathies, the remainder were ischemic cardiomyopathy. Dobutamine dose [250 (200-282) vs. 225 (200-291) µg/min] and duration of therapy [41 (23-79) vs. 53 (24-91) days] was similar between those with and without EMH. Median change in eosinophil count was 0.31 × 10 9 /L in the EMH group compared with only 0.03 × 10 9 /L in the non-EMH cohort, P = 0.02. Increase in peripheral eosinophil count of >0.20 × 10 9 /L demonstrated good discrimination between those with and without EMH, c-statistic 0.83 (95% CI 0.66-1.0). Heart failure hospitalization occurred in 83% of the EMH group versus 59% in the non-EMH group, P = 0.26. Requirement for VAD was significantly higher in the EMH group (83% vs. 41%, P = 0.05). In conclusion, EMH occurred in 14% of patients receiving home dobutamine. Rising eosinophil count should prompt physicians to consider EMH and switch to milrinone to avoid possible escalation to VAD.

The Future of Collaborative Human-Artificial Intelligence Decision-Making for Mission Planning.

In an increasingly complex military operating environment, next generation wargaming platforms can reduce risk, decrease operating costs, and improve overall outcomes. Novel Artificial Intelligence (AI) enabled wargaming approaches, based on software platforms with multimodal interaction and visualization capacity, are essential to provide the decision-making flexibility and adaptability required to meet current and emerging realities of warfighting. We highlight three areas of development for future warfighter-machine interfaces: AI-directed decisional guidance, computationally informed decision-making, and realistic representations of decision spaces. Progress in these areas will enable development of effective human-AI collaborative decision-making, to meet the increasing scale and complexity of today's battlespace.

Levosimendan and Continuous Outpatient Support With Inotropes in Patients With Advanced Heart Failure: A Single-Centre Descriptive Study.

ABSTRACT: To describe the use of levosimendan in a quaternary referral center with a dedicated heart failure service and compare its efficacy and safety to continuous outpatient support with inotropes (COSI) among patients with advanced heart failure (AHF) who require bridge-to-decision (BTD) or bridge-to-transplant (BTT) therapy. This study was a retrospective, single-center, descriptive study of patients with AHF who received either a single levosimendan infusion or COSI between 2018 and 2021. A total of 23 patients received a levosimendan infusion, and 14 were started on COSI. Three indications for levosimendan were identified: (1) to facilitate weaning of continuous inotropes, (2) to augment diuresis in cardiorenal syndrome, and (3) as first-line therapy for cardiogenic shock in selected patients. Eighty-three percent (19 of 23) of patients who received levosimendan survived to discharge, and there were few clinically significant adverse events. Overall survival at 12 months among patients who received levosimendan was 74%. No statistically significant difference in survival was observed at 12 months (P = 0.68) or beyond (P = 0.63) between patients who received levosimendan and were discharged with a plan for BTD or BTT and those who received COSI. Levosimendan is a safe and effective short-term therapy in AHF and offers comparable long-term survival to COSI in patients who require BTD or BTT therapy.

Vasoplegia Following Orthotopic Heart Transplantation: Prevalence, Predictors and Clinical Outcomes.

BACKGROUND: Patients undergoing heart transplant are at high risk for postoperative vasoplegia. Despite its frequency and association with poor clinical outcomes, there remains no consensus definition for vasoplegia, and the predisposing risk factors for vasoplegia remain unclear. Accordingly, the aim of this study was to evaluate the prevalence, predictors, and clinical outcomes associated with vasoplegia in a contemporary cohort of patients undergoing heart transplantation. METHODS: This was a retrospective cohort study of patients undergoing heart transplantation from January 2015 to December 2019. A binary definition of vasoplegia of a cardiac index of 2.5 L/min/m2 or greater and requirement for norepinephrine (≥5 µg/min), epinephrine (≥4 µg/min), or vasopressin (≥1 unit/h) to maintain a mean arterial blood pressure of 65 mm Hg, for 6 consecutive hours during the first 48 hours postoperatively, was used in determining prevalence. Given the relatively low threshold for the binary definition of vasoplegia, patients were divided into tertiles based on their cumulative vasopressor requirement in the 48 hours following transplant. Outcomes included all-cause mortality, intubation time, intensive care unit length of stay, and length of total hospitalization. RESULTS: After exclusion of patients with primary cardiogenic shock, major bleeding, or overt sepsis, data were collected on 95 eligible patients. By binary definition, vasoplegia incidence was 66.3%. We separately stratified by actual vasopressor requirement tertile (high, intermediate, low). Stratified by tertile, patients with vasoplegia were older (52.7 ± 10.2 vs 46.8 ± 12.7 vs 44.4 ± 11.3 years, P = .02), with higher rates of chronic kidney disease (18.8% vs 32.3% vs 3.1%, P = .01) and were more likely to have been transplanted from left ventricular assist device support (n = 42) (62.5% vs 32.3% vs 37.5%, P = .03). Cardiopulmonary bypass time was prolonged in those that developed vasoplegia (155 min [interquartile range 135-193] vs 131 min [interquartile range 117-152] vs 116 min [interquartile range 102-155], P = .003). Intubation time and length of intensive care unit and hospital stay were significantly increased in those that developed vasoplegia; however, this difference did not translate to a significant increase in all-cause mortality at 30 days or 1 year. CONCLUSIONS: Vasoplegia occurs at a high rate after heart transplantation. Older age, chronic kidney disease, mechanical circulatory support, and prolonged bypass time are all associated with vasoplegia; however, this study did not demonstrate an associated increase in all-cause mortality LAY SUMMARY: Patients undergoing heart transplantation are at high risk of vasoplegia, a condition defined by low blood pressure despite normal heart function. We found that vasoplegia was common after heart transplant, occurring in 60%-70% of patients after heart transplant after excluding those with other causes for low blood pressure. Factors implicated included age, poor kidney function, prolonged cardiopulmonary bypass time and preoperative left ventricular assist device support. We found no increased risk of death in patients with vasoplegia despite longer lengths of stay in intensive care and in hospital.

Improvement in functional capacity with spironolactone masks the treatment effect on exercise blood pressure.

OBJECTIVES: A hypertensive response to submaximal exercise is associated with cardiovascular disease but this relationship is influenced by functional capacity. Spironolactone improves functional capacity, which could mask treatment effects on exercise blood pressure. This study sought to examine this hypothesis. DESIGN: Retrospective analysis of a randomized clinical trial. METHODS: 102 participants (54 ±â€¯9 years; 52% male) with a hypertensive response to maximal exercise (systolic BP ≥210 mm Hg men; ≥190 mm Hg women) were randomized to 3-month spironolactone 25 mg daily (n = 53) or placebo (n = 49). Submaximal exercise blood pressure was measured during low-intensity cycling (50, 60 or 70% age-predicted maximal heart rate). Functional capacity was measured as maximal oxygen capacity obtained during a maximal treadmill exercise test, and (resting) aortic stiffness by carotid-to-femoral pulse wave velocity. RESULTS: Spironolactone improved submaximal exercise systolic blood pressure vs. placebo (-4 ±â€¯16 vs. 2 ±â€¯15 mm Hg, p = 0.045, Cohen's d = 0.42), and had a small (but non-statistically significant) improvement in functional capacity (0.64 ±â€¯5.10 vs. -1.43 ±â€¯5.04 ml/kg/min, p = 0.06, Cohen's d = 0.4). When treatment effects were expressed as the change in submaximal exercise systolic blood pressure relative to the change in functional capacity, a larger effect size was observed (-0.3 ±â€¯1.1 vs. 0.3 ±â€¯1.1 mm Hg/ml·kg·min-1, p = 0.01, Cohen's d = 0.58), but was not explained by improved aortic stiffness. CONCLUSIONS: Spironolactone reduces submaximal exercise blood pressure, but this treatment effect may be hidden by improved functional capacity and a non-fixed workload. This highlights the most clinically relevant exercise blood pressure is at a low intensity and fixed workload where the influence of fitness on exercise blood pressure is removed, and the effects of therapy can be appreciated.

Extreme climate event promotes phenological mismatch between sexes in hibernating ground squirrels.

Hibernating ground squirrels rely on a short active period for breeding and mass accrual, and are thus vulnerable to extreme climate events that affect key periods in their annual cycle. Here, we document how a heatwave in March 2012 led to a phenological mismatch between sexes in Richardson's ground squirrels (Urocitellus richardsonii). Females emerged from hibernation and commenced breeding earlier in 2012 relative to average female emergence. Although males had descended testes and pigmented scrota, it appeared that not all males were physiologically prepared to breed since 58.6% of males had non-motile sperm when breeding commenced. Body condition, relative testes size, and the relative size of accessory glands were significant predictors of sperm motility. Males with non-motile sperm had smaller accessory glands than males with motile sperm. There was no decrease in the number of juveniles that emerged in 2012 or female yearlings recruited in 2013, nor did juveniles emerge later than other years. The impact of this heatwave on male ground squirrels emphasizes the importance of assessing the consequences of climate change on the breeding success of hibernating species in both sexes, since the different sensitivity to external cues for emergence led to a mismatch in timing under this event.