Longer Left Ventricular Electric Delay Reduces Mitral Regurgitation After Cardiac Resynchronization Therapy: Mechanistic Insights From the SMART-AV Study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy).

Background: Mitral regurgitation (MR) is associated with worse survival in those undergoing cardiac resynchronization therapy (CRT). Left ventricular (LV) lead position in CRT may ameliorate mechanisms of MR. We examine the association between a longer LV electric delay (QLV) at the LV stimulation site and MR reduction after CRT.

A Diet Rich in Medium-Chain Fatty Acids Improves Systolic Function and Alters the Lipidomic Profile in Patients With Type 2 Diabetes: A Pilot Study.

Context: Excessive cardiac long-chain fatty acid (LCFA) metabolism/storage causes cardiomyopathy in animal models of type 2 diabetes. Medium-chain fatty acids (MCFAs) are absorbed and oxidized efficiently. Data in animal models of diabetes suggest MCFAs may benefit the heart.

Type 2 diabetes, obesity, and sex difference affect the fate of glucose in the human heart.

Type 2 diabetes, obesity, and sex difference affect myocardial glucose uptake and utilization. However, their effect on the intramyocellular fate of glucose in humans has been unknown. How the heart uses glucose is important, because it affects energy production and oxygen efficiency, which in turn affect heart function and adaptability.

Pilot study of pioglitazone and exercise training effects on basal myocardial substrate metabolism and left ventricular function in HIV-positive individuals with metabolic complications.

Background: Individuals with HIV infection and peripheral metabolic complications have impaired basal myocardial insulin sensitivity that is related to left ventricular (LV) diastolic dysfunction. It is unknown whether interventions shown to be effective in improving peripheral insulin sensitivity can improve basal myocardial insulin sensitivity and diastolic function in people with HIV and peripheral metabolic complications.

Objective: In a pilot study, we evaluated whether the peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist pioglitazone or combined endurance and resistance exercise training improves basal myocardial insulin sensitivity and diastolic function in HIV+ adults with peripheral metabolic complications.

Relationships among HIV infection, metabolic risk factors, and left ventricular structure and function.

Our objective was to determine if the presence of metabolic complications (MC) conveyed an additional risk for left ventricular (LV) dysfunction in people with HIV. HIV⁺ and HIV⁻ men and women were categorized into four groups: (1) HIV⁺ with MC (43±7 years, n=64), (2) HIV⁺ without MC (42±7 years, n=59), (3) HIV⁻ with MC (44±8 years, n=37), or (4) HIV⁻ controls without MC (42±8 years, n=41). All participants underwent two-dimensional (2-D), Doppler, and tissue Doppler echocardiography.

Reduced diastolic function and left ventricular mass in HIV-negative preadolescent children exposed to antiretroviral therapy in utero.

Objective: Abnormalities in left ventricular morphology and function have been reported in HIV-negative infants exposed to antiretroviral therapy (ART) in utero that persists throughout preschool age. The objective of this study was to determine if these abnormalities persist, resolve, or worsen during preadolescence.

Design: Cross-sectional observation study.

Substrate metabolism during basal and hyperinsulinemic conditions in adolescents and young-adults with Barth syndrome.

Background: Barth syndrome (BTHS) is a rare X-linked disorder that is characterized by mitochondrial abnormalities, infantile or childhood onset of cardioskeletal myopathy, and high mortality rates. It is currently unknown if BTHS related mitochondrial dysfunction results in substrate metabolism abnormalities and thereby contributes to cardioskeletal myopathy in patients with BTHS.

Methods: Adolescents and young adults with BTHS (n = 5, 20 ± 4 yrs) and age and activity matched healthy controls (n = 5, 18 ± 4 yrs) underwent an hyperinsulinemic-euglycemic clamp procedure with stable isotopically labeled tracers for measurement of lipolysis, fatty acid oxidation, glucose disposal, and whole-body proteolysis rates; dual energy x-ray absorptiometry for measurement of body composition and 2-D and strain echocardiography for measurement of left ventricular function.

Potential mechanisms underlying the effect of gender on response to cardiac resynchronization therapy: insights from the SMART-AV multicenter trial.

Background: Recent studies demonstrate that women may respond more favorably to cardiac resynchronization therapy (CRT) than do men. The mechanisms remain unclear.

Objectives: To describe the effects of gender on response to CRT and to explore potential mechanisms behind these differences.

Effects of human immunodeficiency virus and metabolic complications on myocardial nutrient metabolism, blood flow, and oxygen consumption: a cross-sectional analysis.

Background: In the general population, peripheral metabolic complications (MC) increase the risk for left ventricular dysfunction. Human immunodeficiency virus infection (HIV) and combination anti-retroviral therapy (cART) are associated with MC, left ventricular dysfunction, and a higher incidence of cardiovascular events than the general population. We examined whether myocardial nutrient metabolism and left ventricular dysfunction are related to one another and worse in HIV infected men treated with cART vs.

Abnormalities in cardiac structure and function in adults with sickle cell disease are not associated with pulmonary hypertension.

Background: In sickle cell disease (SCD), pulmonary hypertension (assessed by tricuspid regurgitant jet [TRJ] velocity ≥ 2.5 m/sec) is associated with increased mortality. The relationships among TRJ velocity and left ventricular (LV) and right ventricular (RV) systolic and diastolic function (i.

Myocardial oxygen consumption change predicts left ventricular relaxation improvement in obese humans after weight loss.

Obesity adversely affects myocardial metabolism, efficiency, and diastolic function. Our objective was to determine whether weight loss can ameliorate obesity-related myocardial metabolism and efficiency derangements and that these improvements directly relate to improved diastolic function in humans. We studied 30 obese (BMI >30 kg/m2) subjects with positron emission tomography (PET) (myocardial metabolism, blood flow) and echocardiography (structure, function) before and after marked weight loss from gastric bypass surgery (N = 10) or moderate weight loss from diet (N = 20).

Primary results from the SmartDelay determined AV optimization: a comparison to other AV delay methods used in cardiac resynchronization therapy (SMART-AV) trial: a randomized trial comparing empirical, echocardiography-guided, and algorithmic atrioventricular delay programming in cardiac resynchronization therapy.

Background: one variable that may influence cardiac resynchronization therapy response is the programmed atrioventricular (AV) delay. The SmartDelay determined av optimization: a comparison to other AV delay methods used in cardiac resynchronization therapy (SMART-AV) trial prospectively randomized patients to a fixed empirical AV delay (120 milliseconds), echocardiographically optimized AV delay, or AV delay optimized with SmartDelay, an electrogram-based algorithm.

Methods And Results: a total of 1014 patients (68% men; mean age, 66 ± 11 years; mean left ventricular ejection fraction, 25 ± 7%) who met enrollment criteria received a cardiac resynchronization therapy defibrillator, and 980 patients were randomized in a 1:1:1 ratio.

Are normative values for LV geometry and mass based on fundamental imaging valid with use of harmonic imaging?

Background: Multiple studies have reported echocardiographically determined normal reference values for left ventricular (LV) mass (LVM) derived using fundamental imaging (FI). Modern ultrasound systems now use harmonic imaging (HI) because of the improved LV endomyocardial definition. However, the 2005 American Society of Echocardiography (ASE) recommendations noted that the applicability of the reference values to HI-derived measurements has not been established.

Central aortic pressure is independently associated with diastolic function.

Background: Studies investigating the association between central aortic pressures and diastolic function have been limited.

Methods: Consecutive ambulatory patients (n = 281, mean age 49 +/- 13 years, 49% male) with normal left ventricular (LV) systolic function were included. The LV filling pressure (E/Em) was estimated by Doppler-derived ratio of mitral inflow velocity (E) to septal (Em) by tissue Doppler, LV relaxation by Em, and central aortic pressures by radial tonometry.

Association and interaction of PPAR-complex gene variants with latent traits of left ventricular diastolic function.

Background: Abnormalities in myocardial metabolism and/or regulatory genes have been implicated in left ventricular systolic dysfunction. However, the extent to which these modulate left ventricular diastolic function (LVDF) is uncertain.

Methods: Independent component analysis was applied to extract latent LVDF traits from 14 measured echocardiography-derived endophenotypes of LVDF in 403 Caucasians.

Effect of moderate diet-induced weight loss and weight regain on cardiovascular structure and function.

Objectives: The objective of this prospective, single-site, 2-year dietary intervention study was to evaluate the effects of moderate weight reduction and subsequent partial weight regain on cardiovascular structure and function.

Background: Obesity is associated with adverse cardiac and vascular structural and functional alterations.

Methods: Sixty obese subjects (age 46 + or - 10 years, body mass index 37 + or - 3 kg/m(2)) were evaluated during their participation in a weight loss study.

SmartDelay determined AV optimization: a comparison of AV delay methods used in cardiac resynchronization therapy (SMART-AV): rationale and design.

Background: The clinical benefit of cardiac resynchronization therapy (CRT) for patients with moderate-to-severely symptomatic heart failure, left ventricular systolic dysfunction, and ventricular conduction delay is established. However, some patients do not demonstrate clinical improvement following CRT. It is unclear whether systematic optimization of the programmed atrioventricular (AV) delay improves the rate of clinical response.

Role of serotoninergic pathways in drug-induced valvular heart disease and diagnostic features by echocardiography.

Serotonin plays a significant role in the development of carcinoid heart disease, which primarily leads to fibrosis and contraction of right-sided heart valves. Recently, strong evidence has emerged that the use of specific drug classes, such as ergot alkaloids (for migraine headaches), 5-hydroxytryptamine (5-HT or serotonin) uptake regulators or inhibitors (for weight reduction), and ergot-derived dopamine agonists (for Parkinson's disease), can result in left-sided heart valve damage that resembles carcinoid heart disease. Recent studies have suggested that both right-sided and left-sided drug-induced heart valve disease involves increased serotoninergic activity and in particular activation of the 5-HT receptors, including the 5-HT2B receptor subtype, which mediate many of the central and peripheral functions of serotonin.

Interatrial conduction time and left atrial function in patients with left ventricular systolic dysfunction: effects of cardiac resynchronization therapy.

Background: Prolonged interatrial conduction time (IACT) can be associated with abnormal left atrial (LA) function but has not been characterized in patients with left ventricular (LV) systolic dysfunction (LVSD) and QRS intervals >130 ms.

Methods: Two-dimensional Doppler echocardiography and Doppler tissue imaging (DTI) were performed in 41 patients with LVSD (mean LV ejection fraction, 26 +/- 5%) and 41 similarly aged normal controls. Two-dimensional measurements included LV volume and ejection fraction and LA volume for the determination of LA emptying fraction and LA ejection fraction.

Acute hemodynamic effects of atrial pacing with cardiac resynchronization therapy.

Background: Chronotropic incompetence is common among patients with advanced heart failure (HF), thus atrial pacing (AP) is frequently utilized in this population. The hemodynamic effects of AP during cardiac resynchronization therapy (CRT) have not been well studied.

Objective: The purpose of this study was to compare the acute hemodynamic response during CRT of AP with that during atrial sensing (AS).