Left Ventricular Pump Research Articles

Restoration of myocellular copper-trafficking proteins and mitochondrial copper enzymes repairs cardiac function in rats with diabetes-evoked heart failure.

Diabetes impairs systemic copper regulation, and acts as a major independent risk factor for heart failure (HF) wherein mitochondrial dysfunction is a key pathogenic process. Here we asked whether diabetes might alter mitochondrial structure/function and thus impair cardiac performance by damaging myocellular pathways that mediate cell-copper homeostasis. We measured activity of major mitochondria-resident copper-enzymes cytochrome c oxidase (mt-Cco) and superoxide dismutase 1 (mt-Sod1); expression of three main mitochondrial copper-chaperones [Cco copper chaperone 17 (Cox17), Cox11, and mitochondria-resident copper chaperone for Sod1 (mt-Ccs)]; of copper-dependent Cco-assembly protein Sco1; and regulation of mitochondrial biogenesis, in left-ventricular (LV) tissue from groups of non-diabetic-control, untreated-diabetic, and divalent-copper-selective chelator-treated diabetic rats. Diabetes impaired LV pump function; ∼halved LV-copper levels; substantively decreased myocellular expression of copper chaperones, and enzymatic activity of mt-Cco and mt-Sod1. Divalent-copper chelation with triethylenetetramine improved cardiac pump function, restored levels of myocardial copper, the copper chaperones, and Sco1; and enzymatic activity of mt-Cco and mt-Sod1. Copper chelation also restored expression of the key mitochondrial biogenesis regulator, peroxisome-proliferator-activated receptor gamma co-activator-1α (Pgc-1α). This study shows for the first time that altered myocardial copper-trafficking is a key pathogenic process in diabetes-evoked HF. We also describe a novel therapeutic effect of divalent-copper-selective chelation, namely restoration of myocellular copper trafficking, which is thus revealed as a potentially tractable target for novel pharmacological intervention to improve cardiac function.

Tirofiban in Suspected Left Ventricular Assist Device Pump Thrombosis.

Antithrombotic optimization with a glycoprotein IIb/IIIa inhibitor has been used for the treatment of suspected pump thrombosis, but available literature with tirofiban is lacking. This study aims to describe the use of tirofiban for suspected pump thrombosis. This was a single-center cohort study of left ventricular assist device patients who received tirofiban for the treatment of suspected pump thrombosis from January 1, 2016 to July 31, 2017. Tirofiban was initiated at 0.1 μg/kg/min in patients with normal renal function and subsequent dose adjustments for altered renal function or history of bleeding were employed. Success was defined as resolution of lactate dehydrogenase back to patients' known baseline. Fourteen patients were included for 16 total instances of tirofiban use during the time period. Tirofiban was continued for a median of 5 days (range: 0.3-35 days). Successful treatment was achieved in 12 of the 16 tirofiban uses (75%). Seven bleeding events occurred while on therapy, two major and five minor. This study showed a majority of patients achieved success with tirofiban for suspected pump thrombosis. For patients who are not current candidates for pump exchange or transplant, tirofiban may be considered a therapeutic medical management option.

Clinical characteristics and outcome in patients with a delayed presentation after ST-elevation myocardial infarction and complicated by cardiogenic shock

ObjectiveDelayed presentation after ST-elevation myocardial infarction (STEMI) and complicated by cardiogenic shock (CS-STEMI) is commonly encountered in developing countries and is a challenging scenario because of a delay in revascularization resulting in infarction of a large amount of the myocardium. We aimed to assess the clinical characteristics, angiographic profile, and predictors of outcome in patients with a delayed presentation after CS-STEMI. MethodsA total of 147 patients with CS-STEMI with time to appropriate medical care ≥12 h after symptom onset were prospectively recruited at a tertiary referral center. ResultsThe median time to appropriate care was 24 h (interquartile range 18–48 h). The mean age was 58.7 ± 11.1 years. Left ventricular pump failure was the leading cause of shock (67.3%), whereas mechanical complications accounted for 14.9% and right ventricular infarction for 13.6% of cases. The overall in-hospital mortality was 42.9%. Acute kidney injury [Odds ratio (OR) 8.04; 95% confidence intervals (CI) 3.08–20.92], ventricular tachycardia (OR 7.04; CI 2.09–23.63), mechanical complications (OR 6.46; CI 1.80–23.13), and anterior infarction (OR 3.18; CI 1.01–9.97) were independently associated with an increased risk of mortality. Coronary angiogram (56.5%) revealed single-vessel disease (45.8%) as the most common finding. Percutaneous coronary intervention was performed in 53 patients (36%), at a median of 36 h (interquartile range 30–72) after symptom onset. ConclusionPatients with a delayed presentation after CS-STEMI were younger and more likely to have single-vessel disease. We found a high in-hospital mortality of 42.9%. Appropriate randomized studies are required to evaluate the optimal treatment strategies in these patients.

LVAD Pulsatility Assesses Cardiac Contractility: In Vitro Model Utilizing the Total Artificial Heart and Mock Circulation.

There is a need for a consistent, reproducible, and cost-effective method of determining cardiac recovery in patients who receive emerging novel therapeutics for advanced and end-stage heart failure (HF). With the increasing use of ventricular assist devices (VADs) in end-stage HF, objective device diagnostics are available for analysis. Pulsatility, one of the accessible diagnostic measures, is a variable gage of the differential between peak systolic and minimum diastolic flow during a single cardiac cycle. Following implantation of the VAD, HeartWare's HVAD records pulsatility regularly. Thus, we hypothesize that this measurement relates to the contractility of the heart and could be utilized as a metric for determining patient response to various therapeutics. In this study, therefore, we develop a translatable and effective predictive model characterizing pulsatility to determine HF status and potential HF recovery using the SynCardia Total Artificial Heart (TAH) in conjunction with a Donovan Mock Circulation System to create a simulation platform for the collection of pulsatility data. We set the simulation platform to patient conditions ranging from critical heart failure to a normal operating condition through the variation preload, afterload, and left ventricular (LV) pumping force or TAH "contractility." By manipulating these variables, pulsatility was found to accurately indicate significant (p < 0.05) improvements in LV contractility at every recorded afterload and preload, suggesting that it is a valuable parameter for the assessment of cardiac recovery in patients.

Design an Equivalent Left Ventricular Assist Device for Medical Equipment Labs.

LVAD is a mechanical pump supporting a weak heart function and blood flow. Sometimes, the heart may not recover fast enough to take over the pumping action immediately after surgery, in such patients a temporary support device has been employed to maintain the pumping action until the patient’s own heart recovers. This device can be considered as a temporary alternative before the process of artificial heart transplantation. In this work, a new equivalent Left Ventricular Assist Device (LVAD) is designed and implemented as a simple circuit for medical equipment labs. The presented LVDA consists of a mechanical motor, tubes, a power source, and microcontroller. The output results show the range of readings near the percentage ranges of the left ventricular pumping of the human adult. This work is significant for the biomedical equipment’s lab. The researcher can deal with the function of the important medical devices which are artificial that can record different readings.

Impact of microaxillar mechanical left ventricular support on renal resistive index in patients with cardiogenic shock after myocardial infarction: a pilot trial to predict renal organ dysfunction in cardiogenic shock.

Objectives:To evaluate the effects of left ventricular support with the microaxial left ventricular pump using the Impella device on the renal resistive index assessed by Doppler ultrasonography in haemodynamically stable patients with cardiogenic shock following myocardial infarction.Methods:A non-randomised interventional single-centre study. Consecutive patients with cardiogenic shock supported with an Impella were included during May 2018 and October 2018. The renal resistive index determined as a quotient of (peak systolic velocity – end diastolic velocity)/ peak systolic velocity was obtained using Doppler ultrasound; invasive blood pressure was determined in radial artery simultaneously for safety reasons.Results:A total of 15 patients were measured. The renal resistive index was determined in both kidneys in 13 patients and for one kidney in two patients, respectively. The mean difference between right and left renal resistive index was 0.026 ± 0.023 (P=0.72). When increasing the Impella microaxillar mechanical support by a mean of 0.44 L/min (±0.2 L/min), the renal resistive index decreased significantly from 0.66 ± 0.08 to 0.62 ± 0.06 (P<0.001) consistently in all patients, whereas systolic or diastolic blood pressure remained unchanged.Conclusions:Microaxillar mechanical support by the Impella device in haemodynamically stable patients with cardiogenic shock led to a significant reduction of the renal resistive index without affecting systolic or diastolic blood pressure. This observation is consistent with the notion that Impella support may promote renal organ protection by enhancing renal perfusion.

Deployment of acute mechanical circulatory support devices via the axillary artery

ABSTRACTIntroduction: Use of acute mechanical circulatory support (MCS) devices for high-risk cardiac intervention, cardiogenic shock, and advanced heart failure is growing. Alternate vascular access options for these devices remains a clinical challenge. Building on experience from trans-aortic valve replacement procedures, the axillary artery is becoming a common access route for acute MCS and represents an important advance in the development of acute MCS technologies.Areas covered: Authors review the clinical data and technical aspect of acute MCS deployment via the axillary artery. Axillary access is particularly useful for patients: 1) with severe peripheral vascular disease, 2) with hostile femoral access due to infection, indwelling endovascular devices, or obesity, and 3) to provide early mobility and ambulation. In this review, we discuss the deployment, technical issues and hemostasis regarding the use of intraaortic balloon pump, specifically, axillary intraaortic balloon pumps, trans-valvular left ventricular Impella pumps and arterial outflow of VA-ECMO.Expert opinion: Vascular comorbidities or device design may limit the traditional iliofemoral access route for acute mechanical circulatory support devices. Large bore access for the deployment of these devices through the axillary artery is feasible and safe when appropriate vascular access and closure techniques are used.

ENERGY LOSS BY VECTOR FLOW MAPPING IS ASSOCIATED WITH SYMPTOM SEVERITY AND SERUM BIOMARKERS IN HEART FAILURE PATIENTS WITH REDUCED EJECTION FRACTION

Vector flow mapping (VFM) can quantify left ventricular (LV) flow mechanics noninvasively. VFM can measure LV energy loss and pump efficiency. However, the association of LV energy loss to symptom severity and serum biomarkers in heart failure patients with reduced ejection fraction (HFrEF) is

Telemonitoring and pulmonary artery pressure-guided treatment of heart failure

Heart failure (HF) is an emerging epidemic associated with significant morbidity and mortality, impaired quality of life and high healthcare costs. Despite major advances in pharmacological and device-based therapies, mortality and morbidity have remained high after an index hospitalization for acute cardiac decompensation (ACD). Randomized trials evaluating various forms of noninvasive telemonitoring failed to improve rehospitalization rates in such patients, possibly due to lack of sensitivity of clinical signs and symptoms as early indicators of HF. Among different implantable monitoring devices, wireless remote monitoring of the pulmonary artery pressure (PAP) with the CardioMEMS™ sensor (Abbott, Sylmar, CA, USA) has been shown to be safe and clinically effective in the USA. The patients showed substantial reductions in hospital admissions for ACD, irrespective of left ventricular pump function, because PAP-guided HF management facilitates timely recognition of incipient ACD and appropriate modification of medical treatment before hospitalization becomes unavoidable. These encouraging results have also stimulated evaluation of this novel technology outside the USA. Studies are also underway in Europe and European HF guidelines recommend considering implantation of aCardioMEMS™ sensor in high-risk patients (class IIb-B). More technologically refined implantable hemodynamic monitoring systems allowing, for example, left atrial pressure measurements, are under development. Promising novel approaches to using information from such devices include continuous hemodynamic monitoring and patient self-management based on the pressure information. Thus, pressure-guided HF management is likely to further expand in the future and may help improve clinical outcomes also in high-risk HF populations.

ASSESSMENT OF LEFT VENTRICULAR DYSFUNCTION IN PATIENTS WITH CORONARY HEART DISEASE DURING MINIMALLY INVASIVE SURGERY ACCORDING TO LUNG COMPUTED TOMOGRAPHY DATA

Objective: to assess whether multislice computed tomography (MSCT) of the lung can be used to diagnose the early manifestations of heart failure in patients with coronary heart disease (CHD) during minimally invasive surgical interventions.Material and methods. Lung MSCT was performed in 54 patientsaged 43 to 89 years with CHD before and after interventions. The identified group included 24 patients who had undergone coronary stenting, 26 who had cardiac pacemaker implantation, and 4 patients who had conduction pathways ablation. Left ventricular failure was assessed by hemodynamic disorders in the pulmonary circulation, by taking into account the use of known pathophysiological data. Successive lung MSCT examinations were performed before and after minimally invasive surgical interventions, by recording local densitometric changes in the lung parenchyma.Results. A procedure was proposed to objectively assess comparable ling MSCT images in the same patient in the special imaging window. The density of the lung parenchyma reduced by more than 10 Hounsfield units in 24 patients in the next periods after surgery, which was regarded as a sign of better left ventricular pumping function. Conclusion. The study showed that lung MSCT was highly sensitive in diagnosing left ventricular dysfunction in patients with CHD with improved coronary blood flow and normalized heart rate.

Left ventricular pumping during the transition-adaptation sequence in preterm infants: impact of the patent ductus arteriosus.

BackgroundPostnatally, the immature left ventricle (LV) is subjected to high systemic afterload. Hypothesizing that LV pumping would change during transition-adaptation, we analyzed the LV in preterm infants (GA≤32+6), clinically stable or with a hemodynamically significant patent ductus arteriosus (hPDA) by applying a pump model.MethodsPumping was characterized by EA (effective arterial elastance, reflecting afterload), EES (end-systolic LV elastance, reflecting contractility), EA/EES coupling ratios, descriptive EA:EES relations, and EA/EES graphs. Data calculated from echocardiography and blood pressure were analyzed by diagnosis (S group: clinically stable, no hPDA, n=122; hPDA group, n=53) and by periods (early transition: days of life 1-3; late transition: 4-7; and adaptation: 8-30).ResultsS group: LV pumping was characterized by an increased EA/EES coupling ratio of 0.65 secondary to low EES in early transition, a tandem rise of both EA and EES in late transition, and an EA/EES coupling ratio of 0.45 secondary to high EES in adaptation; hPDA group: time-trend analyses showed significantly lower EA (P<0.0001) and EES (P=0.006). Therefore, LV pumping was characterized by a lower EA/EES coupling ratio (P=0.088) throughout transition-adaptation.ConclusionsIn stable infants, facing high afterload, the immature LV, enhanced by the physiological PDA, increases its contractility. In hPDA, facing low afterload, the overloaded immature LV exhibits a consistently lower contractility.

Decreased ATP production and myocardial contractile reserve in metabolic heart disease

Metabolic syndrome is a cluster of obesity-related metabolic abnormalities that lead to metabolic heart disease (MHD) with left ventricular pump dysfunction. Although MHD is thought to be associated with myocardial energetic deficiency, two key questions have not been answered. First, it is not known whether there is a sufficient energy deficit to contribute to pump dysfunction. Second, the basis for the energy deficit is not clear. To address these questions, mice were fed a high fat, high sucrose (HFHS) ‘Western’ diet to recapitulate the MHD phenotype. In isolated beating hearts, we used 31P NMR spectroscopy with magnetization transfer to determine a) the concentrations of high energy phosphates ([ATP], [ADP], [PCr]), b) the free energy of ATP hydrolysis (∆G~ATP), c) the rate of ATP production and d) flux through the creatine kinase (CK) reaction. At the lowest workload, the diastolic pressure-volume relationship was shifted upward in HFHS hearts, indicative of diastolic dysfunction, whereas systolic function was preserved. At this workload, the rate of ATP synthesis was decreased in HFHS hearts, and was associated with decreases in both [PCr] and ∆G~ATP. Higher work demands unmasked the inability of HFHS hearts to increase systolic function and led to a further decrease in ∆G~ATP to a level that is not sufficient to maintain normal function of sarcoplasmic Ca2+-ATPase (SERCA). While [ATP] was preserved at all work demands in HFHS hearts, the progressive increase in [ADP] led to a decrease in ∆G~ATP with increased work demands. Surprisingly, CK flux, CK activity and total creatine were normal in HFHS hearts. These findings differ from dilated cardiomyopathy, in which the energetic deficiency is associated with decreases in CK flux, CK activity and total creatine. Thus, in HFHS-fed mice with MHD there is a distinct metabolic phenotype of the heart characterized by a decrease in ATP production that leads to a functionally-important energetic deficiency and an elevation of [ADP], with preservation of CK flux.

Left Ventricular Assist Device Inflow Cannula Position May Contribute to the Development of HeartMate II Left Ventricular Assist Device Pump Thrombosis.

Pump thrombosis (PT) is a dreaded complication after left ventricular assist device (LVAD) implantation. Problems with inflow cannula (IC) position may precipitate thrombus development. We sought to determine if IC position contributes to the development of PT. We conducted a retrospective review of 76 HeartMate II LVAD implants. The angle of the IC (AIC) to the horizontal plane was measured on chest x-rays. Patients who developed PT (PT group) were compared to the remaining patients (control group). The mean age at implantation was 56 ± 14 years, and 82% of the patients were male. Ten patients (13%) developed PT. Six (60%) required device exchange, and 4 (40%) were managed with anticoagulation and/or thrombolysis. The median AIC for all patients at implantation was 59° (range, 38°-98°; 25th-75th interquartile range, 50°-75°). In the PT group, the median AIC was larger at the time of PT diagnosis compared to implantation (70° vs 60°, P = 0.005). In the control group, the median AIC was also larger at follow-up compared to implantation (61° vs 58°, P < 0.001) although to a lesser degree than in the PT group. No difference was seen in the median AIC between the PT group and the control group at implantation (60° vs 58°, respectively; P = 0.668) or at follow-up (70° vs 61°, respectively; P = 0.309). However, the median AIC at follow-up in the PT group was significantly larger than the median AIC at implantation in the control group (70° vs 58°, respectively; P = 0.014). The HeartMate II LVAD IC position contributes to the development of PT. Regular monitoring of cannula position may help identify patients at risk for this problem.

HVAD Waveform Analysis as a Noninvasive Marker of Pulmonary Capillary Wedge Pressure: A First Step Toward the Development of a Smart Left Ventricular Assist Device Pump.

Flow waveforms are an important feature of the HVAD left ventricular assist device (LVAD) that provides information about HVAD function and patient hemodynamics. We assessed the properties of one specific aspect of the waveform, the slope of the ventricular filling phase (VFP), and its correlation with pulmonary capillary wedge pressure (PCWP). A total of 101 screenshots from the HVAD monitor and simultaneous hemodynamic measurements were obtained simultaneously during sequential stages of invasive hemodynamic ramp studies. Each screenshot was digitized (IGOR Pro, WaveMetrics Inc., Oswego, OR) and properties of the flow waveforms including instantaneous flow and rate of change of flow were analyzed. Ventricular filling phase slope (VFPS) was calculated for each screenshot and correlated to PCWP. Ventricular filling phase slope was significantly higher in patients with PCWP ≥ 18 mm Hg than in patients with PCWP < 18 mm Hg [6.25 (5.84-7.37) L/min/s vs. 3.27 (2.00-4.69) L/min/s, p ≤ 0.0001]. A VFPS threshold of 5.8 L/min/s predicted a PCWP ≥ 18 mm Hg with a sensitivity of 87% and specificity of 95% (AUC 0.95). Ventricular filling phase slope of the HVAD flow waveform is a novel noninvasive parameter that correlates with PCWP and can discriminate elevated versus normal or low PCWP. Automated reporting of this parameter may help clinical assessment and management of patients supported by an HVAD and may serve as the basis of a smart LVAD pump that can adapt in response to changes in a patient's physiology.

Clinical treatment of severe pneumonia complicated with heart failure in children

Objective: This study aimed to investigate the clinical curative effects of dopamine and phentolamine on severe pneumonia complicated with heart failure in children. Methods: Fifty-eight children with severe pneumonia complicated with heart failure were selected as research objects. All of the patients were randomly divided into two groups, namely, control group (n=29) and observation group (n=29). The children in the control group were treated with dopamine, whereas the children in the observation group were administered with phentolamine based on the treatment in the control group. Clinical curative effects, time of improvement in clinical signs and changes in cardiac function before and after the treatment in both groups were observed and compared. Results: The total effective rate of the clinical treatment in children in the observation group was 96.55% which was significantly higher than that in the control group (68.96%). After the treatment was administered, the Heart Rate (HR), left ventricular end-diastolic diameter and left ventricular ejection fraction of the children were 119 ± 6 times/min, 32 ± 3 mm and 73% ± 10% in the observation group and 136 ± 9 times/min, 38 ± 4 mm and 58% ± 10% in the control group, respectively. After the treatment was given, the HR of the children in the observation group decreased significantly, the left ventricular end-diastolic diameter reduced and the left ventricular pumping ability significantly increased. The stable breathing time, disappearance time of pulmonary rales, time of improvement in HR, liver retraction time and hospitalisation time of children were 1.3 ± 0.6, 8.1 ± 1.6, 1.7 ± 0.5, 2.1 ± 1.2 and 10.1 ± 2.3 d in the observation group and 2.5 ± 0.4, 11.6 ± 1.5, 2.7 ± 0.5, 3.6 ± 1.2 and 14.3 ± 2.8 d in the control group, respectively. The time of improvement in each clinical sign in the observation group was significantly shorter than that in the control group. Conclusion: The clinical curative effect of dopamine combined with phentolamine in the treatment of severe pneumonia complicated with heart failure in children is clear and can significantly improve the cardiac function, enhance the left ventricular pumping ability and reduce the HR and left ventricular end-diastolic diameter of children. Thus, this effect can shorten the time of improvement in clinical signs of children. It can also reduce the hospitalisation time of children. Consequently, the suffering of children and the economic burden against children and their family members can be considerably alleviated. Thus, the effect has a high clinical application value.

Long-term clinical outcomes in patients with cardiogenic shock according to left ventricular function: The French registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI) programme

Cardiogenic shock (CS) complicating acute myocardial infarction (AMI) remains a major concern. Failure of the left ventricular (LV) pump is the primary insult in most forms of CS, but other parts of the circulatory system and diastolic function contribute to shock. However, little is known of the clinical presentation, management and outcomes according to LV function in these patients. To assess the presentation, management and clinical outcomes in patients admitted for AMI with CS according to early LV ejection fraction (LVEF), using long-term data from the French registry of Acute ST-elevation or non-ST-elevation Myocardial Infarction (FAST-MI) 2010. We analysed baseline characteristics, management and 3-year mortality in patients with CS, according to LVEF (≤40% vs>40%). The analyses were replicated in the FAST-MI 2005 cohort. Among 4169 patients with AMI included in the survey, the incidence of CS was 3.3%. LVEF was>40% in 43%. Early PCI (≤24hours) was used more often in patients with LV dysfunction (61% vs 42%), as was the use of optimal medical therapy at discharge (66% vs 40%). CS remained associated with a major increase in 3-year mortality, both in patients with LVEF ≤40% (55%) and in those with LVEF>40% (44%). Using Cox multivariable analysis, LVEF ≤40% was associated with higher 3-year mortality (hazard ratio 2.08, 95% confidence interval 1.15-3.78) in patients with AMI with CS. Consistent results were found in the replication cohort. Despite the many circulatory system contributors to the physiopathology of CS in patients with AMI, the occurrence of early LV systolic dysfunction is associated with higher long-term mortality.

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

It is now well recognized that heart failure (HF) patients with left bundle branch block (LBBB) derive substantial clinical benefits from cardiac resynchronization therapy (CRT), and LBBB has become one of the important predictors for CRT response. The conventional tachypacing-induced HF model has several major limitations, including absence of stable LBBB and rapid reversal of left ventricular (LV) dysfunction after cessation of pacing. Hence, it is essential to establish an optimal model of chronic HF with isolated LBBB for studying CRT benefits. In the present study, a canine model of asynchronous HF induced by left bundle branch (LBB) ablation and 4 weeks of rapid right ventricular (RV) pacing is established. The RV and right atrial (RA) pacing electrodes via the jugular vein approach, together with an epicardial LV pacing electrode, were implanted for CRT performance. Presented here are the detailed protocols of radiofrequency (RF) catheter ablation, pacing leads implantation, and rapid pacing strategy. Intracardiac and surface electrograms during operation were also provided for a better understanding of LBB ablation. Two-dimensional speckle tracking imaging and aortic velocity time integral (aVTI) were acquired to validate the chronic stable HF model with LV asynchrony and CRT benefits. By coordinating ventricular activation and contraction, CRT uniformed the LV mechanical work and restored LV pump function, which was followed by reversal of LV dilation. Moreover, the histopathological study revealed a significant restoration of cardiomyocyte diameter and collagen volume fraction (CVF) after CRT performance, indicating a histologic and cellular reverse remodeling elicited by CRT. In this report, we described a feasible and valid method to develop a chronic asynchronous HF model, which was suitable for studying structural and biologic reverse remodeling following CRT.

Atrioventricular dromotropathy: evidence for a distinctive entity in heart failure with prolonged PR interval?

Heart failure (HF) is often accompanied by atrioventricular (AV) conduction disturbance, represented by prolongation of the PR interval on the electrocardiogram. Studies suggest that PR prolongation exists in at least 10% of HF patients, and it seems more prevalent in the presence of prolonged QRS duration. A prolonged PR interval may result in elevated left ventricular (LV) end-diastolic pressure, diastolic mitral regurgitation, and reduced LV pump function. This seems especially the case in patients with heart disease, in whom it is associated with an increased risk for atrial fibrillation, advanced AV heart block, HF, and death. These findings point towards the importance of proper AV coupling in HF patients. A few studies, strongly differing in design, suggest that restoration of AV coupling in patients with PR prolongation by pacing improves cardiac function and clinical outcomes. These observations argue for AV-dromotropathy as a potential target for pacing therapy, but other studies show inconsistent results. Given its potential clinical implications, restoration of AV coupling by pacing warrants further investigation. Additional possible future research goals include assessing different techniques to measure compromised AV coupling, determine the best site(s) of ventricular pacing, and assess a potential influence of diastolic mitral regurgitation in the efficacy of such therapy.

Circulating endothelial progenitor cells as a marker of left ventricular pump function in ischemic chronic heart failure

Circulating endothelial progenitor cells as a marker of left ventricular pump function in ischemic chronic heart failure

Mitochondrial mechanisms in septic cardiomyopathy

Background Sepsis is the abnormal immune and inflammatory response to infection that may ultimately result in multi-organ failure. Lacking of effective therapy, sepsis and septic shock remain as leading causes of death, especially in patients that sepsis led to severe myocardial dysfunction. However, the mechanisms underlying myocardial injury following sepsis are not clear. Objective This review discusses that sepsis may cause cardiomyopathy through damaging mitochondrial function. Content The major manifestations of septic cardiomyopathy include right and left ventricular pump failure. In sepsis, many substances, including toxins, cytokines, reactive oxygen species, and nitric oxide, are released, and subsequently mobilize a series of pathological procedures, such as, calcium overload, mitochondrial dysfunction, autophage, and apoptosis. Mitochondrial dysfunction and energy depletion likely contribute to septic cardiomyopathy. Trend Early diagnosis of myocardial dysfunction and restoration of normal mitochondrial function may be an effective strategy in the treatment of sepsis and septic shock. Key words: Sepsis; Cardiomyopathy; Mitochondrial dysfunction