Search results for "Heart Ventricles"
showing 10 items of 162 documents
Identification to cardiac conduction cells in humans and pigs according to their zonal distribution, using histological, immunohistochemical and morp…
2021
Abstract Histologically, the cardiac conduction network is formed of electrically isolated subendocardial fibers that comprise specialized cells with fewer myofibrils and mitochondria than cardiomyocytes. Our aim is to uncover regional variations of cardiac conduction fibers through histological and morphometric study in a porcine and human model. We analyzed five male adult human hearts and five male pig hearts. The left ventricles were dissected and sectioned in the axial plane into three parts: basal, middle third and apex regions. Cardiac conduction fibers study was carried out using hematoxylin-eosin and Masson's trichrome staining, and cardiac conduction cells and their junctions were…
Exercise stress CMR reveals reduced aortic distensibility and impaired right-ventricular adaptation to exercise in patients with repaired tetralogy o…
2018
International audience; The aim of our study was to evaluate the feasibility of exercise cardiac magnetic resonance (CMR) in patients with repaired tetralogy of Fallot (RTOF) and to assess right and left ventricular adaptation and aortic wall response to exercise in comparison with volunteers.Methods11 RTOF and 11 volunteers underwent prospective CMR at rest and during exercise. A supine bicycle ergometer was employed to reach twice the resting heart rate during continuous exercise, blood pressure and heart rate were recorded. Bi-ventricular parameters and aortic stiffness were assessed using accelerated cine sequences and flow-encoding CMR. A t-test was used to compare values between group…
Different mechanisms of the inhibition of the transient outward current in rat ventricular myocytes.
1994
The mechanism of drug-induced inhibition of the transient outward current, Ito, has been investigated in rat ventricular myocytes using the whole cell patch clamp technique. Ito was activated by 300 ms depolarizing voltage clamp steps in 10 mV increments from −50 mV up to +40 mV. At +40 mV, Ito peaked after about 3 ms, and the time course of inactivation was appropriately described by two time constants, τfast = 17 ms and τslow = 203 ms. Verapamil, quinidine sulfate and nifedipine preferentially depressed Ito at the end of the 300 ms depolarizing voltage clamp step; the inactivation of Ito was accelerated by all drugs, whereas peak Ito was less affected. The time course of drug action at +4…
Hypoxia and myocardial remodeling in human cardiac allografts: a time-course study.
2009
Background: Cardiac allografts are known to develop myocardial fibrosis, which may be a cause of progressive cardiac dysfunction. Apart from the renin‐angiotensin and transforming growth factor- system, hypoxia has been proposed as an important player in the pathogenesis of fibrosis, but its significance remains unclear. This study examines the degree of myocardial fibrosis, cellular remodeling and hypoxic signaling over a time-course of 10 years after human cardiac allograft transplantation. Methods: Serial right ventricular biopsies of 57 patients were collected in 6-month intervals after cardiac transplant surgery for a total of 10 years to allow a retrospective longitudinal analysis. Ov…
Normal Reference Ranges for Echocardiography: Rationale, study design, and methodology (NORRE Study)
2013
International audience; BACKGROUND: Availability of normative reference values for cardiac chamber dimensions, volumes, mass, and function is a prerequisite for the accurate application of echocardiography for both clinical and research purposes. However, due to the lack of consistency in current echocardiographic 'reference values', their use for clinical decision-making remains questionable. AIMS: The aim of the 'Normal Reference Ranges for Echocardiography Study (NORRE Study)' is to obtain a set of 'normal values' for cardiac chamber geometry and function in a large cohort of healthy Caucasian individuals aged over a wide range of ages (25-75 years) using both conventional and advanced e…
Anticoagulant drugs in noncompaction: A mandatory therapy?
2008
BACKGROUND: Noncompaction of left ventricular myocardium is a rare congenital cardiomyopathy resulting from an incomplete myocardial morphogenesis that leads to the persistence of the embryonic myocardium. This condition is characterized by a thin compacted epicardial and an extremely thickened endocardial layer with prominent trabeculations and deep intertrabecular recesses. It is not clear, in noncompaction of myocardium, whether intertrabecular recesses could be responsible for thrombi formation and thromboembolic complications. METHODS: The prevalence of stroke and echocardiographic finding of thrombus was evaluated in a continuous series of 229 patients (men and women) affected by nonc…
Prognostic Implications of Tissue Doppler Imaging-Derived E/Ea Ratio in Acute Heart Failure Patients
2014
Background Tissue Doppler–derived transmitral to mitral annular early diastolic velocity ratio (E/Ea), as a noninvasive estimation of left ventricular (LV) filling pressures, is a strong prognosticator in various cardiac scenarios including chronic heart failure; nevertheless, its utility for risk stratification in the whole spectrum of acute heart failure (AHF) patients remains elusive. Thus, the aim of this study was to determine the association between E/Ea ratio and 1-year mortality in nonselected patients with AHF. Methods The study included 417 consecutive patients admitted for AHF. Twenty-two patients were excluded due to nonaccurate Ea measurements, leaving the final sample to be 39…
Cardiovascular risk factors, angiotensin-converting enzyme gene I/D polymorphism, and left ventricular mass in systemic hypertension.
1999
We investigated the influence of major cardiovascular risk factors (smoking, hypercholesterolemia, diabetes mellitus) on the association between angiotensin-converting enzyme (ACE) gene insertion (I)/deletion (D) polymorphism and echocardiographic left ventricular mass in 225 patients with sustained hypertension, assessed by ambulatory blood pressure monitoring. When the study population was analyzed as a whole, the 3 ACE genotypes did not differ in left ventricular mass (II, 47 g/m2.7; ID, 49 g/m2.7; DD, 51 g/m2.7; p = NS). No difference was found in subjects (n = 135) in whom at least 1 major cardiovascular risk factor was present (II, 51 g/m2.7; ID, 51 g/m2.7; DD: 52 g/m2.7; p = NS). In …
Long-term beneficial effects of PTCA on segmental early relaxation in disease of the left anterior descending coronary artery.
1988
The relationship between regional left ventricular (LV) motion and global pressure relaxation of the left ventricle remains unclear. To clarify the recent concept of segmental early relaxation in coro nary artery disease, the authors in vestigated two groups of patients. In group I, all 12 patients (mean age 47±7 years) exhibited evidence of a normal heart after an extensive in vestigation. In group II, 25 patients (55±7 years) presented an isolated stenosis of the left anterior descend ing coronary artery, and they under went a hemodynamic investigation before and after (six to nine months) a durable successful percutaneous transluminal coronary angioplasty (PTCA). After all conventional …
Transmural distribution of biochemical markers of total protein and collagen synthesis, myocardial contraction speed and capillary density in the rat…
1988
The effect of angiotensin II-induced hypertension on selected biochemical parameters was studied in Sprague-Dawley rats. Angiotensin II infusion at rates of 41.7 micrograms h-1 kg-1 and 12.5 micrograms h-1 kg-1 for 2, 5, 10 and 15 days elevated the systolic blood pressure from 143 +/- 7 mmHg to 215-230 mmHg (P less than 0.001) and 185-195 mmHg (P less than 0.001), respectively. The left ventricular weight/body weight ratio increased 10-14% (P less than 0.05) and 23-32% (P less than 0.001) after 2-15 days in rats treated at the lower and higher infusion rates, respectively. Prolyl 4-hydroxylase (PH) activity, a marker of collagen synthesis, was evenly distributed in the left ventricle. PH ac…