Abstract:
:The isovolumic index is a recently described echocardiographic parameter of left ventricular function that is calculated as the ratio between the sum of the time of isovolumic contraction and relaxation divided by the ejection time. Although the individual components of this index may be altered by heart rate and loading conditions, an analysis of the net effect of such alterations on the isovolumic index has not been undertaken. Thus, dogs were instrumented with high-fidelity micromanometers in the left ventricle, ascending aorta, and left atrium to allow determination of the individual components of the isovolumic index and calculation of the index itself. Four sets of experiments were undertaken in random order. Left atrial pacing was used to increase heart rate by approximately 10 bpm in five steps. Preload was elevated in five stages by saline infusions which caused successive increases of 1 to 2 mm Hg in the left ventricular end-diastolic pressure. Systolic blood pressure was lowered or raised by approximately 10 mm Hg per stage by three progressive, steady-state infusions of nitroprusside and phenylephrine, respectively. These experiments demonstrated little change in the isovolumic index over a broad range of heart rate. Increased left ventricular end-diastolic pressure and decreased systemic pressure caused shortening of the index. Multiple regression analysis of all experiments yielded the following: isovolumic index = 0.41 - 0.015 (left ventricular end-diastolic pressure) + 0.004 (systolic blood pressure); r = 0.57, standard error = 0.13, p less than 0.0001. Therefore, this investigation establishes the hemodynamic determinants of the isovolumic index and provides the basis for interpretation of directional changes in response to cardiac diseases and cardioactive drugs that can alter loading conditions.
journal_name
Am Heart Jjournal_title
American heart journalauthors
Mancini GB,Friedman HZ,Hramiec JE,DeBoe SFdoi
10.1016/0002-8703(86)90476-xsubject
Has Abstractpub_date
1986-10-01 00:00:00pages
791-9issue
4eissn
0002-8703issn
1097-6744pii
0002-8703(86)90476-Xjournal_volume
112pub_type
杂志文章abstract:BACKGROUND:In patients with atrial fibrillation, incomplete adherence to anticoagulants increases risk of stroke. Non-warfarin oral anticoagulants (NOACs) are expensive; we evaluated whether higher copayments are associated with lower NOAC adherence. METHODS:Using a national claims database of commercially-insured pat...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2020.12.010
更新日期:2021-01-14 00:00:00
abstract::We attempted to determine whether exercise-induced silent myocardial ischemia has different clinical implications in patients with and without pathologic Q waves. We studied 152 patients (121 men and 31 women) who had ischemic ST depression (greater than or equal to 0.05 mV) during exercise tests and greater than or e...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(90)90009-m
更新日期:1990-09-01 00:00:00
abstract::Automatic external defibrillators (AEDs) represent an important technologic innovation in the management of out-of-hospital cardiac arrest. We propose the following concept: AEDs are machines with the limited task of ventricular fibrillation (VF) identification, countershock delivery, and defibrillation. They cannot b...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(85)90002-x
更新日期:1985-12-01 00:00:00
abstract:BACKGROUND:Atrioventricular septal defect (AVSD) and double outlet right ventricle (DORV) with normally related great arteries and normal ventricular sizes are associated with a good long-term prognosis after biventricular (BV) repair. The outcome of cases with a borderline small left ventricle (bLV) is unclear. The pu...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2006.04.018
更新日期:2006-07-01 00:00:00
abstract::Current evidence suggests that the pathogenesis of atrial fibrillation (AF) is multifactorial. The observation that AF, once present, alters the electrophysiologic properties of the atrial myocardium causing self-perpetuation of the arrhythmia raised the importance of electrical remodeling in its pathogenesis. Althoug...
journal_title:American heart journal
pub_type: 杂志文章,评审
doi:10.1016/j.ahj.2008.10.009
更新日期:2009-02-01 00:00:00
abstract:BACKGROUND:Although inflammation is a core element of atherogenesis and plasma levels of fibrinogen (FGB), homocysteine, and intercellular adhesion molecule-1 (ICAM-1) differ by race/ethnicity, little is known about the role of genetic polymorphisms in the FGB, methylenetetrahydrofolate reductase (MTHFR), and ICAM-1 ge...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2008.12.012
更新日期:2009-04-01 00:00:00
abstract:BACKGROUND:The inverse relation between alcohol intake and clinical coronary artery disease (CAD) is well established, although the mechanisms remain speculative. We studied the relation between alcohol intake and subclinical CAD to assess the possible role of alcohol in atherogenesis. METHODS:We conducted a prospecti...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2004.05.023
更新日期:2004-11-01 00:00:00
abstract:BACKGROUND:In patients with acute myocardial infarction (AMI), depressive symptoms increase the risk for cardiac events. Recently, the S allele of the serotonin transporter (5-HTT) gene-linked polymorphic region was shown to reduce transcription of this gene and thus reduce serotonin reuptake, and this allele is linked...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2005.03.062
更新日期:2005-10-01 00:00:00
abstract::In the United States there has been a dramatic decrease in age-adjusted coronary heart disease (CHD) mortality during the last 20 years. This article investigates the reasons for this decline and concludes that most of the decline in CHD has been the result of life-style changes, particularly reduction in serum choles...
journal_title:American heart journal
pub_type: 杂志文章,评审
doi:10.1016/s0002-8703(05)80054-7
更新日期:1990-03-01 00:00:00
abstract::Antiarrhythmic therapy for prevention of sustained ventricular tachycardia is commonly guided by programmed electrical stimulation, and the persistent ability to initiate ventricular tachycardia during drug therapy often leads to the use of nonpharmacologic therapies such as surgery. Prior studies suggest that program...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(05)80325-4
更新日期:1990-04-01 00:00:00
abstract:BACKGROUND:Postinterventional cognitive dysfunction (PICD) is a known complication of coronary artery bypass grafting (CABG). However, it is largely unknown whether PICD occurs after coronary catheterization. METHODS:Neuropsychologic data were obtained from 37 patients who received coronary catheterization and 47 pati...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2011.07.021
更新日期:2011-10-01 00:00:00
abstract:BACKGROUND:Several non-vitamin K antagonist oral anticoagulant (NOAC) alternatives to warfarin are available for stroke prevention in atrial fibrillation (AF). We aimed to describe the factors associated with selection of NOACs versus warfarin in patients with new onset AF. METHODS:The ORBIT-AF II study is a national,...
journal_title:American heart journal
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1016/j.ahj.2017.03.024
更新日期:2017-07-01 00:00:00
abstract::Mitochondria in skeletal and cardiac muscle have been found to be less stable in aging hamsters, in contrast to preparations from young animals. We have found previously that clofibrate (Atromid-S) will reverse this degeneration in the older hamsters. This study examined the exercise tolerance of aged hamsters, to see...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(77)80040-9
更新日期:1977-10-01 00:00:00
abstract::The effects of amiodarone on delayed afterdepolarization (DAD) and triggered automaticity induced by low potassium (0.5 mEq/L) were evaluated on isolated rabbit right ventricular muscles, by means of standard microelectrode techniques. Triggered automaticity was induced in 6 of 10 muscles in the control group, in four...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(87)90267-5
更新日期:1987-02-01 00:00:00
abstract::Twenty-six patients with Ebstein's anomaly were classified into three types according to their clinical features, heart catheterization data, angiocardiographic and anatomical findings which were obtained on surgery or autopsy. The hemodynamics in each type were discussed. 1. Tricuspid Stenosis Dominant Type. Eight pa...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(78)90458-1
更新日期:1978-02-01 00:00:00
abstract:BACKGROUND:Stroke is a rare but serious event that complicates the course of patients with acute coronary syndromes (ACS). The type, outcome, and risk factors of stroke occurring in stabilized patients with ACS have not been previously reported. METHODS:We evaluated stroke incidence, subtypes, and outcomes, in additio...
journal_title:American heart journal
pub_type: 临床试验,杂志文章,多中心研究,随机对照试验
doi:10.1016/j.ahj.2004.01.028
更新日期:2004-09-01 00:00:00
abstract:BACKGROUND:Vascular wall shear stress (WSS) has been implied in the pathogenesis of atherosclerosis and vascular remodeling. Our aim was to calculate WSS after balloon angioplasty and evaluate its predictive value for long-term outcome. METHODS:WSS was calculated proximal to, in, and distal to the lesion after angiogr...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1067/mhj.2002.123110
更新日期:2002-07-01 00:00:00
abstract::The records of 64 patients with progressive systemic sclerosis (PSS) were reviewed. More than 100 items from the patient's history, physical examination, and laboratory tests were encoded. A two-tailed Gehan's test was used to evaluate the effect of each variable on patient survival. Variables significant at the 0.05 ...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(85)90525-3
更新日期:1985-07-01 00:00:00
abstract:BACKGROUND:Accurate, reproducible, noninvasive determination of left ventricular (LV) volumes and ejection fraction (EF) is important for clinical assessment, risk stratification, selection of therapy, and serial monitoring of patients with cardiovascular disease. Three-dimensional echocardiography (3DE) approaches hav...
journal_title:American heart journal
pub_type: 临床试验,杂志文章
doi:10.1067/mhj.2000.108513
更新日期:2000-09-01 00:00:00
abstract:BACKGROUND:The 2020 American Heart Association Impact Goal aims to improve cardiovascular health of all Americans by 20% while reducing deaths from cardiovascular disease and stroke by 20%. A large step toward this goal would be to better understand and take advantage of the significant intersection between behavior an...
journal_title:American heart journal
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.ahj.2017.02.020
更新日期:2017-05-01 00:00:00
abstract:BACKGROUND:Patients undergoing percutaneous coronary intervention (PCI) for unstable coronary syndromes have substantial emotional and spiritual distress that may promote procedural complications. Noetic (nonpharmacologic) therapies may reduce anxiety, pain and distress, enhance the efficacy of pharmacologic agents, or...
journal_title:American heart journal
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1067/mhj.2001.119138
更新日期:2001-11-01 00:00:00
abstract:BACKGROUND:Angiotensin-converting enzyme (ACE) inhibitors are established as first-line therapy in chronic heart failure (CHF). However, conflicting results exist regarding the dose-effect relation of ACE inhibitors. METHODS:We investigated 45 patients (age 55 +/- 10 years) with stable CHF who presented with a mainten...
journal_title:American heart journal
pub_type: 临床试验,杂志文章
doi:10.1016/s0002-8703(99)70179-1
更新日期:1999-10-01 00:00:00
abstract:BACKGROUND:Depressive symptoms in patients with heart failure (HF) are common and might be associated with inflammation. No studies have examined both the cross-sectional and prospective association between inflammation and depressive symptoms in patients with HF with adequate correction for disease severity. The aim o...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2011.03.011
更新日期:2011-06-01 00:00:00
abstract::The P and the Ta waves of two patient groups with A-V block were magnified with a direct-current amplifier and recorded at a high paper speed. In Group A patients (those without serious cardiovascular complications except A-V block) the P and the Ta waves were recorded in the opposite direction in every lead and there...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(76)80533-9
更新日期:1976-06-01 00:00:00
abstract:BACKGROUND:Patients with heart failure (HF) frequently have comorbidities. Frequency, prognostic, and therapeutic implications of chronic obstructive pulmonary disease (COPD) in HF are largely unknown. We aimed to assess the prevalence and prognostic implications of COPD in a sample of stable patients with HF and to de...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2007.10.040
更新日期:2008-03-01 00:00:00
abstract::This case report presents a young adult with asymmetric septal hypertrophy (ASH) and syncope. Infranodal complete heart block was demonstrated as his cause for syncope. Therapy consisted of implantation of a A-V sequential pacemaker. Cardiac output determinations and systolic time intervals demonstrated the beneficial...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(77)80177-4
更新日期:1977-01-01 00:00:00
abstract:BACKGROUND:Dual antiplatelet therapy with aspirin and clopidogrel is currently recommended in off-pump coronary artery bypass (OPCAB). However, no data exist concerning platelet reactivity on clopidogrel after OPCAB. The aim of this study was to assess the relationship between platelet reactivity and late major adverse...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2014.01.016
更新日期:2014-06-01 00:00:00
abstract::Release of thromboxane (TXA2) during acute myocardial infarction may be an important contributing factor in the genesis of ventricular fibrillation (VF). We assessed the effect of selective TXA2 inhibition on vulnerability to VF after total occlusion of the anterior descending coronary artery in chloralose-anesthetize...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(86)90099-2
更新日期:1986-04-01 00:00:00
abstract:BACKGROUND:Despite significant attention to resuscitation care by hospitals, national data on trends in the incidence and survival of patients with inhospital cardiac arrest (IHCA) are limited. OBJECTIVE:To determine trends and hospital-level variation in the incidence and outcomes associated with IHCA. In exploratory...
journal_title:American heart journal
pub_type: 杂志文章,多中心研究
doi:10.1016/j.ahj.2017.05.018
更新日期:2017-11-01 00:00:00
abstract:BACKGROUND:Diastolic dysfunction induced by ischemia may alter transmitral blood flow, but this reflects global ventricular function, and pseudonormalization may occur with increased preload. Tissue Doppler may assess regional diastolic function and is relatively load-independent, but limited data exist regarding its a...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1067/mhj.2002.123836
更新日期:2002-09-01 00:00:00