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1. Assessment of ventricular mechanical synchronization after left bundle branch pacing using 2‐D speckle tracking echocardiography

   https://doi.org/10.1002/clc.23481  

   Sun, Zhijun ; Di, Beibing ; Gao, Huikuan ; Lan, Dihui ; Peng, Hui ( October 2020 , Clinical Cardiology)

   The left bundle branch pacing (LBBP) makes the ventricular depolarization closer to the physiological state and shortens QRS duration. The purpose of this study is to explore the ventricular systolic mechanical synchronization after LBBP in comparison with traditional right ventricular pacing (RVP) using two‐dimensional strain echocardiography (2D‐STE).

   Thirty‐two patients who received LBBP (n = 16) or RVP (n = 16) from October 2018 to October 2019 and met the inclusion criteria were included in this retrospective study. Electrocardiogram (ECG) characteristics, pacing parameters, pacing sites, and safety events were assessed before and after implantation. Acquisition and analysis of ventricular systolic synchronization were implemented using 2D‐STE.

   In RVP group, ECG showed left bundle branch block patterns. At LBBP, QRS morphology was in the form of right bundle branch block, and QRS durations were significantly shorter than that of the RVP QRS (109.38 ± 12.89 vs 149.38 \± 19.40 ms,P < .001). Both the maximum time differences (TD) and SDs of the 18‐segments systolic time to peak systolic strain were significantly shorter under LBBP than under RVP (TD, 66.62 ± 37.2 vs 148.62 ± 43.67 ms,P < .01; SD, 21.80 ± 12.13 vs 52.70 ± 17.72 ms,P < .01), indicating that LBBP could provide better left ventricular mechanical synchronization. Left and right ventricular pre‐ejection period difference was significantly longer in RVP group than in LBBP group (10.23 ± 3.07 vs 39.94 ± 14.81 ms,P < .05), indicating left and right ventricular contraction synchronization in LBBP group being better than in RVP group.

   LBBP is able to provide a physiologic ventricular activation pattern, which results in ventricular mechanical contraction synchronization.

    

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2. Sex differences in the incidence and mode of death in rats with heart failure with preserved ejection fraction

   https://doi.org/10.1113/EP089163  

   Elkholey, Khaled ; Morris, Lynsie ; Niewiadomska, Monika ; Houser, Jeremy ; Ramirez, Michelle ; Tang, Mulan ; Humphrey, Mary Beth ; Stavrakis, Stavros ( January 2021 , Experimental Physiology)

   What is the central question of this study?

   Prior studies failed to address the role of sex in modifying the pathophysiology and response to therapy in heart failure with preserved ejection fraction (HFpEF), potentially introducing bias into translational findings. We aimed to explore sex differences in outcomes and sought to identify the underlying mechanisms in a well‐established rat model of HFpEF.

   What is the main finding and its importance?

   Male rats with HFpEF exhibited worse survival compared with females and were at a higher risk for sudden death, attributable in part to QT prolongation, autonomic dysregulation and enhanced inflammation. These data might provide the basis for the development of sex‐specific interventions in HFpEF targeting these abnormalities.

   Heart failure with preserved ejection fraction (HFpEF) accounts for 50% of heart failure, and sudden death is the leading cause of mortality. We aimed to explore sex differences in outcomes in rats with HFpEF and sought to identify the underlying mechanisms. Dahl salt‐sensitive rats of either sex were randomized into high‐salt diet (HS diet; 8% NaCl,n = 46, 50% female) or low‐salt diet (LS diet; 0.3% NaCl;n = 24, 50% female) at 7 weeks of age. After 6 and 10 weeks of LS or HS diets, the ECG, heart rate variability, cytokines and echocardiographic parameters were measured. The animals were monitored daily for development of HFpEF and survival. Over 6 weeks of HS diet, rats developed significant hypertension and signs of HFpEF. Compared with female HS diet‐fed rats, males exhibited more left ventricular dilatation, a longer QT interval, and worse autonomic tone, as assessed by heart rate variability and elevated inflammatory cytokines. Ten of 23 (46%) male rats died during follow‐up, compared with two of 23 (9%) female rats (P = 0.01). There were four sudden deaths in males (with ventricular tachycardia documented in one rat), whereas the females died of heart failure. In conclusion, male rats with HFpEF exhibit worse survival compared with females and are at a higher risk for sudden death, attributable in part to QT prolongation, autonomic dysregulation and enhanced inflammation. These data might provide the basis for the development of sex‐specific interventions in HFpEF targeting these abnormalities.

    

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3. Sodium tanshinone IIA sulfonate prevents the adverse left ventricular remodelling: Focus on polymorphonuclear neutrophil‐derived granule components

   https://doi.org/10.1111/jcmm.14306  

   Mao, Shuai ; Taylor, Shalina ; Chen, Qubo ; Zhang, Minzhou ; Hinek, Aleksander ( May 2019 , Journal of Cellular and Molecular Medicine)

   The aims of this study were to evaluate the effects of sodium tanshinone IIA sulfonate (STS) on left ventricular (LV) remodelling after for ST‐elevated myocardial infarction (STEMI).

   In this prospective, randomized clinical trial, 101 patients with the ST‐elevated MI (STEMI) and a successful reperfusion were immediately randomized to receive STS (80 mg qd for 7 days) or saline control, along with standard therapy. The primary effectiveness endpoint is the % change in LV end diastolic volumes index (%∆ LVEDVi) as measured by echocardiography from baseline to 6 months. Secondary effectiveness endpoints include 6‐month period for major adverse cardiac events (MACE), including the occurrence of recurrent myocardial infarction, death, hospitalization for heart failure and malignant arrhythmia. The 6‐month changes in %∆ LVEDVi were significantly smaller in the STS group than in the control group [−5.05% vs 3.32%;P < 0.001]. With respect to MACE, there was a significant difference between those who received STS (8.16%) and those patients on control (26.00%) (P = 0.019). Meaningfully, results of parallel tests aimed at mechanistic explanation of the reported clinical effects, revealed a significantly reduced levels of neutrophils‐derived granule components in the blood of STS treated patients.

   We found that short‐term treatment with STS reduced progressive left ventricular remodelling and subsequent better clinical outcome that could be mechanistically linked to the inhibition of the ultimate damage of infarcted myocardium by infiltrating neutrophils.

    

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4. Risk factors and select cardiac characteristics in dogs naturally infected with Trypanosoma cruzi presenting to a teaching hospital in Texas

   https://doi.org/10.1111/jvim.15516  

   Meyers, Alyssa C. ; Hamer, Sarah A. ; Matthews, Derek ; Gordon, Sonya G. ; Saunders, Ashley B. ( May 2019 , Journal of Veterinary Internal Medicine)

   Chagas disease, caused by the protozoan parasiteTrypanosoma cruzi, causes sudden death and chronic heart disease with no currently approved treatment.

   To report epidemiologic and select cardiac characteristics associated withT. cruziinfection in dogs presenting to a teaching hospital in Texas.

   Three hundred seventy‐five client‐owned dogs.

   A retrospective search of medical records identified dogs tested forT. cruziantibodies or with histologicT. cruziparasites. Data retrieved included signalment, location of residence, reported reason for testing, cardiac troponin I (cTnI) concentration, and ECG abnormalities.

   Trypanosoma cruzi‐infected dogs (N = 63, 16.8%) were significantly younger than negative dogs (N = 312) (mean, 5.9 ± 3.8 versus 7.4 ± 4.0 years;P = .007) with no difference by sex or breed. Ninety‐one breeds were tested; the highest percent infected were non‐sporting (10/35; 29%) and toy breed (10/42; 24%) groups. The odds of infection were 13 times greater among dogs with an infected housemate or littermate (95% confidence interval [CI], 3.94‐50.45;P< .001). Infected dogs were more likely to have ventricular arrhythmias (odds ratio [OR], 2.19; 95% CI, 1.15‐4.33,P = .02), combinations of ECG abnormalities (OR, 2.91; 95% CI, 1.37‐5.99;P = .004), and cTnI >0.129 ng/mL (ADVIA; OR, 10.71; 95% CI, 1.60‐212.21;P = .035).

   Dogs infected withT. cruziwere identified in Texas in many breed groups including breeds affected by well‐described heart diseases that mimic Chagas disease suggesting a need for increased awareness, including knowledge of when to consider testing.

    

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5. Deep phenotyping of cardiac function in heart transplant patients using cardiovascular system models

   https://doi.org/10.1113/JP279393  

   Colunga, Amanda L. ; Kim, Karam G. ; Woodall, N. Payton ; Dardas, Todd F. ; Gennari, John H. ; Olufsen, Mette S. ; Carlson, Brian E. ( June 2020 , The Journal of Physiology)

   Right heart catheterization data from clinical records of heart transplant patients are used to identify patient‐specific models of the cardiovascular system.

   These patient‐specific cardiovascular models represent a snapshot of cardiovascular function at a given post‐transplant recovery time point.

   This approach is used to describe cardiac function in 10 heart transplant patients, five of which had multiple right heart catheterizations allowing an assessment of cardiac function over time.

   These patient‐specific models are used to predict cardiovascular function in the form of right and left ventricular pressure‐volume loops and ventricular power, an important metric in the clinical assessment of cardiac function.

   Outcomes for the longitudinally tracked patients show that our approach was able to identify the one patient from the group of five that exhibited post‐transplant cardiovascular complications.

   Heart transplant patients are followed with periodic right heart catheterizations (RHCs) to identify post‐transplant complications and guide treatment. Post‐transplant positive outcomes are associated with a steady reduction of right ventricular and pulmonary arterial pressures, toward normal levels of right‐side pressure (about 20 mmHg) measured by RHC. This study shows that more information about patient progression is obtained by combining standard RHC measures with mechanistic computational cardiovascular system models. The purpose of this study is twofold: to understand how cardiovascular system models can be used to represent a patient's cardiovascular state, and to use these models to track post‐transplant recovery and outcome. To obtain reliable parameter estimates comparable within and across datasets, we use sensitivity analysis, parameter subset selection, and optimization to determine patient‐specific mechanistic parameters that can be reliably extracted from the RHC data. Patient‐specific models are identified for 10 patients from their first post‐transplant RHC, and longitudinal analysis is carried out for five patients. Results of the sensitivity analysis and subset selection show that we can reliably estimate seven non‐measurable quantities; namely, ventricular diastolic relaxation, systemic resistance, pulmonary venous elastance, pulmonary resistance, pulmonary arterial elastance, pulmonary valve resistance and systemic arterial elastance. Changes in parameters and predicted cardiovascular function post‐transplant are used to evaluate the cardiovascular state during recovery of five patients. Of these five patients, only one showed inconsistent trends during recovery in ventricular pressure–volume relationships and power output. At the four‐year post‐transplant time point this patient exhibited biventricular failure along with graft dysfunction while the remaining four exhibited no cardiovascular complications.

    

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