-
1.
Alpha and beta myosin isoforms and human atrial and ventricular contraction.
Walklate, J, Ferrantini, C, Johnson, CA, Tesi, C, Poggesi, C, Geeves, MA
Cellular and molecular life sciences : CMLS. 2021;(23):7309-7337
-
-
Free full text
-
Abstract
Human atrial and ventricular contractions have distinct mechanical characteristics including speed of contraction, volume of blood delivered and the range of pressure generated. Notably, the ventricle expresses predominantly β-cardiac myosin while the atrium expresses mostly the α-isoform. In recent years exploration of the properties of pure α- & β-myosin isoforms have been possible in solution, in isolated myocytes and myofibrils. This allows us to consider the extent to which the atrial vs ventricular mechanical characteristics are defined by the myosin isoform expressed, and how the isoform properties are matched to their physiological roles. To do this we Outline the essential feature of atrial and ventricular contraction; Explore the molecular structural and functional characteristics of the two myosin isoforms; Describe the contractile behaviour of myocytes and myofibrils expressing a single myosin isoform; Finally we outline the outstanding problems in defining the differences between the atria and ventricles. This allowed us consider what features of contraction can and cannot be ascribed to the myosin isoforms present in the atria and ventricles.
-
2.
Left Ventricular Assist Device Therapy in Older Adults: Addressing Common Clinical Questions.
DeFilippis, EM, Nakagawa, S, Maurer, MS, Topkara, VK
Journal of the American Geriatrics Society. 2019;(11):2410-2419
Abstract
OBJECTIVES To review the literature and summarize the evidence for left ventricular assist device (LVAD) use in older adults (aged >75 years), highlighting patient selection, day-to-day life with an LVAD, age-specific complications, and end-of-life considerations. DESIGN Contemporary review of current literature on LVAD therapy in older adults. RESULTS There is a paucity of data on LVAD use and outcomes in adults older than 75 years and even less commonly are such devices implanted in those older than 80 years. Candidates and recipients of this age often have multiple chronic conditions and extracardiac impairments, which can negatively affect their short-term outcomes and daily experience following LVAD implantation. Therefore, selection prior to implant should incorporate end-organ function, nutritional status, measures of frailty, neurocognitive status, and social support, among others, to determine the patient population most likely to benefit from such therapy. CONCLUSION When LVAD therapy is utilized in an older adult, the needs for multidisciplinary team management and expertise in palliative care are essential. More age-specific outcome data are required to help inform providers, patients, and caregivers. J Am Geriatr Soc 67:2410-2419, 2019.
-
3.
Perioperative Management of the Right and Left Ventricles.
Lampert, BC
Cardiology clinics. 2018;(4):495-506
Abstract
Left ventricular assist devices (LVADs) improve survival in select advanced heart failure patients and rates of LVAD implantation are growing. LVAD support carries significant morbidity and mortality with the greatest risk in the perioperative period. Strategies have evolved to minimize this risk. Medical and mechanical support is used for right and left ventricular optimization. Other strategies emphasize improving nutrition, hematologic abnormalities, infection risk, and renal function. Intraoperative approaches highlight anesthesia-related issues, management of concomitant valve disease, right ventricular failure, and weaning from cardiopulmonary bypass. Postoperative efforts concentrate on augmenting right ventricular function, supporting end-organ recovery, and quickly identifying complications.
-
4.
Obesity and Ventricular Repolarization: a Comprehensive Review.
Omran, J, Bostick, BP, Chan, AK, Alpert, MA
Progress in cardiovascular diseases. 2018;(2):124-135
Abstract
Obesity is known to be a strong predictor of sudden cardiac death. For this reason, concern exists that this association may be related to delayed ventricular repolarization (VR), which has been extensively studied in overweight and obese patients. The corrected QT interval (QTc) and QT or QTc dispersion have been the most commonly-used electrocardiographic methods for assessing VR. Multiple controlled studies demonstrated that QTc and QT or QTc dispersion were significantly longer/greater in overweight and obese subjects than in normal weight controls. The preponderance of evidence indicates that weight loss in overweight and obese patients, whether achieved by diet or bariatric surgery, significantly shortens QTc and decreases QT or QTc dispersion. Several co-morbidities that are commonly associated with obesity may delay VR. These include diabetes mellitus, the metabolic syndrome, systemic hypertension, left ventricular hypertrophy, heart failure, and obstructive sleep apnea. It is unclear whether overweight and obesity are independent predictors of delayed VR. It is also uncertain whether prolongation of QTc in such patients is sufficient to predispose to potentially fatal ventricular arrhythmias.
-
5.
Interrelationship between diabetes mellitus and heart failure: the role of peroxisome proliferator-activated receptors in left ventricle performance.
Oikonomou, E, Mourouzis, K, Fountoulakis, P, Papamikroulis, GA, Siasos, G, Antonopoulos, A, Vogiatzi, G, Tsalamadris, S, Vavuranakis, M, Tousoulis, D
Heart failure reviews. 2018;(3):389-408
Abstract
Heart failure (HF) is a common cardiac syndrome, whose pathophysiology involves complex mechanisms, some of which remain unknown. Diabetes mellitus (DM) constitutes not only a glucose metabolic disorder accompanied by insulin resistance but also a risk factor for cardiovascular disease and HF. During the last years though emerging data set up, a bidirectional interrelationship between these two entities. In the case of DM impaired calcium homeostasis, free fatty acid metabolism, redox state, and advance glycation end products may accelerate cardiac dysfunction. On the other hand, when HF exists, hypoperfusion of the liver and pancreas, b-blocker and diuretic treatment, and autonomic nervous system dysfunction may cause impairment of glucose metabolism. These molecular pathways may be used as therapeutic targets for novel antidiabetic agents. Peroxisome proliferator-activated receptors (PPARs) not only improve insulin resistance and glucose and lipid metabolism but also manifest a diversity of actions directly or indirectly associated with systolic or diastolic performance of left ventricle and symptoms of HF. Interestingly, they may beneficially affect remodeling of the left ventricle, fibrosis, and diastolic performance but they may cause impaired water handing, sodium retention, and decompensation of HF which should be taken into consideration in the management of patients with DM. In this review article, we present the pathophysiological data linking HF with DM and we focus on the molecular mechanisms of PPARs agonists in left ventricle systolic and diastolic performance providing useful insights in the molecular mechanism of this class of metabolically active regiments.
-
6.
Hypertrophic obstructive cardiomyopathy with multiple coronary arteries to right ventricular microfistulas: a case report and review of the literature.
Meena, DS, Meena, CB, Parvez, J
Journal of medical case reports. 2017;(1):24
Abstract
BACKGROUND Coronary artery microfistulas are a rare anomaly; their association with hypertrophic cardiomyopathy is even rarer and can lead to serious cardiac complications owing to coronary steal phenomena such as angina pectoris, myocardial infarction, congestive heart failure, ventricular and supraventricular arrhythmias, syncope, and sudden death. CASE PRESENTATION A 32-year-old Indian woman presented to our institute with severe angina on exertion and multiple episodes of pre-syncope. Echocardiography revealed hypertrophic obstructive cardiomyopathy. Coronary angiography showed no significant atherosclerotic lesions; however, it revealed multiple microfistulas originated from all three major coronary arteries and draining into her right ventricle. This finding was confirmed by the rapid filling of the pulmonary artery after dye was injected into her left coronary artery during a cardiac catheterization study and by a significant oxygen step up of 15 % seen from her right atria to right ventricle during oximetry analysis. We treated our patient's condition with medical therapy including metoprolol and nicorandil. She improved and angina grade had decreased from class III to class II on a follow-up visit 1 month after discharge. CONCLUSIONS In this case report and literature review, we highlight an unusual but important association that can lead to symptomatic worsening of angina in young patients with hypertrophic cardiomyopathy owing to coronary steal phenomena.
-
7.
Current Perspectives on Systemic Hypertension in Heart Failure with Preserved Ejection Fraction.
Tam, MC, Lee, R, Cascino, TM, Konerman, MC, Hummel, SL
Current hypertension reports. 2017;(2):12
-
-
Free full text
-
Abstract
Heart failure with preserved ejection fraction (HFpEF) is a prevalent but incompletely understood syndrome. Traditional models of HFpEF pathophysiology revolve around systemic HTN and other causes of increased left ventricular afterload leading to left ventricular hypertrophy (LVH) and diastolic dysfunction. However, emerging models attribute the development of HFpEF to systemic proinflammatory changes secondary to common comorbidities which include HTN. Alterations in passive ventricular stiffness, ventricular-arterial coupling, peripheral microvascular function, systolic reserve, and chronotropic response occur. As a result, HFpEF is heterogeneous in nature, making it difficult to prescribe uniform therapies to all patients. Nonetheless, treating systemic HTN remains a cornerstone of HFpEF management. Antihypertensive therapies have been linked to LVH regression and improvement in diastolic dysfunction. However, to date, no therapies have definitive mortality benefit in HFpEF. Non-pharmacologic management for HTN, including dietary modification, exercise, and treating sleep disordered breathing, may provide some morbidity benefit in the HFpEF population. Future research is need to identify effective treatments, perhaps in more specific subgroups, and focus may need to shift from reducing mortality to improving exercise capacity and symptoms. Tailoring antihypertensive therapies to specific phenotypes of HFpEF may be an important component of this strategy.
-
8.
Effect of obesity and weight loss on ventricular repolarization: a systematic review and meta-analysis.
Omran, J, Firwana, B, Koerber, S, Bostick, B, Alpert, MA
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2016;(6):520-30
Abstract
We performed a systematic review and meta-analysis of the effects of obesity ± overweight and weight loss on the corrected QT interval (QTc) and QT or QTc dispersion (indices of ventricular repolarization). Mean difference for both QTc and QT or QTc dispersion with 95% confidence intervals (CIs) was calculated comparing obese ± overweight subjects and normal weight controls and QTc and QT or QTc dispersion before and after weight loss from diet ± exercise or bariatric surgery. A total of 22 studies fulfilled the selection criteria. Compared with normal weight controls, there was a significantly longer QTc in obese ± overweight subjects (mean difference of 21.74 msec, 95% CI: 18.76 to 22.32) and significantly longer QT or QTc dispersion (mean difference of 15.17 msec, 95% CI: 13.59 to 16.74). Weight loss was associated with a significant decrease in QTc (mean difference -25.77 msec, 95% CI: -28.33-23.21) and QT or QTc dispersion (mean difference of -13.46 msec, 95% CI: -15.60 to -11.32 in obese ± overweight subjects. Thus, obesity ± overweight is associated with significant prolongation of QTc and QT or QTC dispersion. Weight loss in obese ± overweight subjects produces significant decreases in these variables. © 2016 World Obesity.
-
9.
Effect of Parathyroidectomy Upon Left Ventricular Mass in Primary Hyperparathyroidism: A Meta-Analysis.
McMahon, DJ, Carrelli, A, Palmeri, N, Zhang, C, DiTullio, M, Silverberg, SJ, Walker, MD
The Journal of clinical endocrinology and metabolism. 2015;(12):4399-407
-
-
Free full text
-
Abstract
CONTEXT Primary hyperparathyroidism (PHPT) has been associated with increased left ventricular mass (LVM) in many studies. Most studies have been inadequately powered to assess the effect of parathyroidectomy (PTX) on LVM. OBJECTIVE The objective was to evaluate whether PTX has a benefit on LVM in patients with PHPT. DATA SOURCES Sources included PubMed, Medline, Cochrane Library, clinicaltrials.gov, review articles, and abstracts from meetings. STUDY SELECTION Eligible studies included prospective studies of PTX vs observation or PTX alone in patients with PHPT who had LVM measured by echocardiography. DATA EXTRACTION Two investigators independently identified eligible studies and extracted data. Random-effects models were used to obtain final pooled estimates. DATA SYNTHESIS Fifteen studies (four randomized controlled trials and 11 observational) of 457 participants undergoing PTX were included. PTX was associated with a reduction in LVM (crude Hedges gu -0.290 ± 0.070, 95% confidence interval [CI] -0.423 to -0.157) of 11.6 g/m(2) (12.5%) on average. Effect size estimates differed by study duration (P < .001), with improvements seen in shorter (≤ 6 mo) but not longer studies. There was a trend toward greater improvement in observational studies vs randomized controlled trials (P = .07), and both serum calcium and PTH were higher in the former. Using random-effects models, the estimated effect size remained significant (Hedges gu -0.250, 95% CI -0.450 to -0.050). Higher preoperative PTH but not calcium was associated with a greater decline in LVM (β = -.039, 95% CI -0.075 to -0.004). CONCLUSION PTX reduced LVM in PHPT, and higher preoperative PTH levels were associated with greater improvements. Because the benefit was limited to short-term studies and PHPT disease severity was not independent of study design, further work is needed to clarify the factors that influence the change in LVM and whether the benefit persists beyond 6 months after PTX. Although the clinical significance of the LVM improvement is unclear, these data indicate that PTH may underlie increased LVM in PHPT.
-
10.
[Morphological and molecular bases of cardiac development].
Kobylińska, J, Dworzański, W, Cendrowska-Pinkosz, M, Dworzańska, A, Hermanowicz-Dryka, T, Kiszka, J, Starosławska, E, Burdan, F
Postepy higieny i medycyny doswiadczalnej (Online). 2013;:950-7
Abstract
The heart is a mesoderm-derived organ, whose formation is regulated by various genes. Initially, the most important is expression of Nkx2.5, CR1, pitx2, anf and mhc2a, which are responsible for differentiation of cardiomyocytes. In a later phase activation of mhc2b, pitx2c, mesp1, pcmf1, vmhc, xin, mcl2v, mlc2a, mlc2a, mef2, hand1 and hand2 was revealed. Their expression is regulated by various molecules, including transcription (XIN, GATA, MEF, Tbx5, Baf60c, PECAM, tie-2, MEF2) and growth (VEGF, FGF, PDGF) factors, as well as proteins (i.e., dickkopf-1, cerberus, cytotactin, fibrillin, nodal, thrombomodulin, Wnt, bone morphometric ones - BMP2, BMP 4, BMP5, BMP7) and other substances, such as retinoid and folic acid. Crucial steps in cardiac organogenesis are development of the ventricle and atrial formation, as well as septation and valve formation. Any disturbances of such processes may lead to various congenital heart diseases and defects that could be initiated by various genetic, epigenetic or environmental factors. The most common heart malformations are: stenosis (coarctation) of the aorta and pulmonary trunk, bicuspid aortic valve, atrial and/or ventricular septal defect, persistent truncus arteriosus (Botallo duct), transposition of the great vessels, tricuspid atresia, hypoplastic left and right heart, as well as syndrome of Lutembachera, Cantrell, Ebstein, Eisenmenger and Shone and trilogy, tetralogy, pentalogy of Fallot.