Abstract:
BACKGROUND:Analysis of high-frequency QRS amplitudes (HF-QRS) may provide an additional diagnostic tool in patients with heart disease, but the basic properties of these waveforms have not been sufficiently investigated. This study describes the spatial, individual, and temporal variation at rest of HF-QRS recorded with the 12 standard electrocardiographic leads in patients with ischemic heart disease. METHODS AND RESULTS:Two consecutive electrocardiographic recordings from 67 patients were signal averaged and analyzed within a bandwidth of 150 to 250 Hz. The HF-QRS values were expressed as root mean square values. There was a spatial variation in HF-QRS among the 12 leads, with higher amplitudes in V(2) through V(4), II, aVF, and III. The individual variation among the patients was large for all leads. The sum of the HF-QRS for all 12 leads in each patient ranged from 20 to 75 microV (mean 36 +/- 11 microV). The mean of the temporal variation in HF-QRS for all 12 leads between the 2 recordings was only 0.10 +/- 0. 09 microV. CONCLUSIONS:Because of the large individual variation, analysis of HF-QRS is probably most applicable in monitoring situations when it is possible to track changes in a patient over time. The temporal variation in HF-QRS at rest is small, both in patients with and those without prior myocardial infarction.
journal_name
Am Heart Jjournal_title
American heart journalauthors
Pettersson J,Carro E,Edenbrandt L,Maynard C,Pahlm O,Ringborn M,Sörnmo L,Warren SG,Wagner GSdoi
10.1067/mhj.2000.101782subject
Has Abstractpub_date
2000-02-01 00:00:00pages
352-8issue
2 Pt 1eissn
0002-8703issn
1097-6744pii
S0002-8703(00)90246-1journal_volume
139pub_type
杂志文章abstract::Functional, ambulatory, community-dwelling subjects (n = 423, aged 75 to 85 years) underwent baseline 24-hour ambulatory electrocardiography (ECG) examinations as part of the Bronx Aging Study, a 10-year prospective cohort study designed to identify risk factors and disease markers for cardiovascular, cerebrovascular,...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(96)90425-1
更新日期:1996-08-01 00:00:00
abstract:BACKGROUND:The transmission of 12-lead electrocardiograms from remote locations to hand-held computers of cardiologists is now possible with the development of wireless technology and computer software. This investigation determined whether the cardiologist's decisions regarding reperfusion therapy for patients with sy...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1067/mhj.2000.110288
更新日期:2000-11-01 00:00:00
abstract::Atrial antitachycardia pacing was tested in 23 children and young adults. The majority of these patients had had operative repair of congenital cardiac defects and had both bradycardia and tachycardia. Pacemakers were usually implanted by the transvenous technique using bipolar leads. In each patient it was possible t...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(91)90534-o
更新日期:1991-09-01 00:00:00
abstract:AIMS:Paclitaxel-eluting stents (PESs) have been shown to inhibit neointimal hyperplasia after percutaneous coronary intervention. Coroflex Please (B Braun, Melsungen, Germany) is a newly developed PES. We compared the clinical and angiographic efficacy of Coroflex Please with Taxus Liberte (Boston Scientific, Natick, M...
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.2013.02.009
更新日期:2013-05-01 00:00:00
abstract:BACKGROUND:The long-term prognostic significance of early (<48 hours) ventricular fibrillation (VF) or sustained ventricular tachycardia (VT) in patients with an acute myocardial infarction remains controversial. Emerging data suggest that some of the benefit of renin-angiotensin-aldosterone system (RAAS) antagonism ma...
journal_title:American heart journal
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.ahj.2009.05.023
更新日期:2009-08-01 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::Dobutamine (and dopamine) are potent positive inotropic drugs which are frequently given to treat decompensated congestive heart failure. This study reports on the use of ambulatory dobutamine (and dopamine) infusions in 21 outpatients with advanced congestive heart failure. Each patient was initially hospitalized, an...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(87)90757-5
更新日期:1987-09-01 00:00:00
abstract:BACKGROUND:Hypertrophic cardiomyopathy (HC) is the most prevalent genetic cardiac disease caused by a mutation in sarcomeres, Z-disks, or calcium-handling genes and is characterized by unexplained left ventricular hypertrophy. The aim of this study was to determine the genetic profile of Brazilian patients with HC and ...
journal_title:American heart journal
pub_type: 杂志文章,多中心研究
doi:10.1016/j.ahj.2013.07.029
更新日期:2013-10-01 00:00:00
abstract::In order to validate the measurement of pressure-volume loops and stroke work in humans, simultaneous digital subtraction ventriculography (DSA) and first-pass radionuclide angiocardiography (RNA) coupled with high-fidelity micromanometer left ventricular pressure measurements were undertaken in 34 patients, mean age ...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(89)90234-2
更新日期:1989-11-01 00:00:00
abstract:BACKGROUND:Vein graft failure is a crucial challenge in coronary artery bypass graft (CABG) surgery. Previous studies have suggested a patency benefit of the No-Touch vein harvesting technique, but only with small sample sizes. MATERIALS AND METHODS:This study is a prospective, multicenter randomized clinical trial wi...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2018.11.011
更新日期:2019-04-01 00:00:00
abstract::Because of its unique ability to demonstrate the metabolic consequences of myocardial ischemia, positron emission tomography (PET) is extremely valuable in assessing myocardial viability. PET imaging can identify the myocardial segments that are likely to improve after revascularization and may be more sensitive and s...
journal_title:American heart journal
pub_type: 杂志文章,评审
doi:10.1016/0002-8703(91)90803-p
更新日期:1991-07-01 00:00:00
abstract::We developed a new angiographic score of the extent of coronary disease (extent score), which we compared with conventional stenosis and vessel scores that emphasize the severity of stenosis. Scores were determined in 132 patients (29 women, 103 men with a mean age of 55 +/- 10 years) who underwent elective coronary a...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(05)80173-5
更新日期:1990-06-01 00:00:00
abstract:BACKGROUND:The ODYSSEY COMBO I study (http://clinicaltrials.gov/show/NCT01644175) evaluated efficacy and safety of alirocumab as add-on therapy to stable maximally tolerated daily statin with or without other lipid-lowering therapy in high cardiovascular risk patients with suboptimally controlled hypercholesterolemia. ...
journal_title:American heart journal
pub_type: 杂志文章,多中心研究,随机对照试验
doi:10.1016/j.ahj.2015.03.004
更新日期:2015-06-01 00:00:00
abstract::A population of 2955 patients admitted to the hospital with acute myocardial infarction (AMI) was followed for 1 year after AMI or until death. Smokers as compared to nonsmokers were over 10 years younger (p less than 0.001) and had a lower prevalence of hypertension (p less than 0.01), congestive heart failure (p les...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(85)90071-7
更新日期:1985-09-01 00:00:00
abstract:BACKGROUND:beta-blockers have been shown to benefit patients after myocardial infarction by decreasing mortality, sudden cardiac death, and reinfarction. Although beta-blockers are recommended for all patients with acute coronary syndromes (ACS) without contraindications, a target heart rate (HR) is recommended only fo...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2009.06.023
更新日期:2009-09-01 00:00:00
abstract:BACKGROUND:l-arginine is a commonly consumed dietary conditional essential amino acid found in food items and supplements, which is closely related to asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA). l-arginine is thought to increase nitric oxide and be cardioprotective, whereas ADMA and SDMA m...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2016.07.021
更新日期:2016-12-01 00:00:00
abstract:BACKGROUND:Fractional flow reserve (FFR) has become a gold standard in physiological assessment of coronary artery stenosis. An FFR < 0.75 is considered as a reliable physiological parameter indicating functionally significant lesion. Lesion length (LL) may affect the translesional hemodynamics. However, the effect of ...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/j.ahj.2004.09.007
更新日期:2005-08-01 00:00:00
abstract::Anesthetized dogs were cooled to a core body temperature of 26 degree C. or maintained at a body temperature of 37 degree C. during periods of 5 and 10 hours of LAD coronary artery occlusion. Subsequent macroscopic dehydrogenase enzyme mapping showed that ischemic injury was 25 per cent less after 5 hours of coronary ...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(78)90010-8
更新日期:1978-12-01 00:00:00
abstract::To explore the contribution of reperfusion injury to final infarct size after a short duration of ischemia, closed-chest dogs underwent 40 minutes of proximal left anterior descending artery occlusion followed by 3 days of reperfusion. Animals randomly received intracoronary adenosine (n = 8) at 3.75 mg/min during the...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(91)90272-j
更新日期:1991-12-01 00:00:00
abstract::We tested whether overload of the two ventricles may be associated with a preponderance of interventricular septum in patients with high blood pressure. The rationale is that the septum is shared by the greater and lesser circulation and that in hypertension the latter shows the same qualitative hemodynamic alteration...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(88)90626-6
更新日期:1988-08-01 00:00:00
abstract:BACKGROUND:Protease inhibitors (PIs) may be associated with accelerated atherosclerosis in individuals infected with human immunodeficiency virus (HIV). We assessed the effects of HIV PIs on subclinical atherosclerosis. METHODS:The lipid profiles, C-reactive protein (CRP) levels, coronary artery calcification (CAC) sc...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1067/mhj.2002.125009
更新日期:2002-10-01 00:00:00
abstract::Epinephrine increases coronary blood flow but may not improve the balance between myocardial oxygen supply and demand during cardiopulmonary resuscitation (CPR). The objective of this study was to determine whether this balance can be improved by administering a relatively pure alpha-adrenergic vasoconstrictor, alone ...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(94)90120-1
更新日期:1994-02-01 00:00:00
abstract:BACKGROUND:Despite some concern that recent aspirin ingestion increases blood loss after coronary artery surgery, there is some evidence that this may reduce thrombotic complications. In contrast, antifibrinolytic drugs can reduce blood loss in this setting, but there is concern that they may increase thrombotic compli...
journal_title:American heart journal
pub_type: 杂志文章,多中心研究,随机对照试验
doi:10.1016/j.ahj.2007.10.003
更新日期:2008-02-01 00:00:00
abstract::There are selective blocking agents (antagonists) for alpha receptors and beta receptors. These blocking agents prevent the response to injected agonists and neurogenically released norepinephrine. The principal cardiovascular response to alpha blockade is postural hypotension with reflexly induced cardiac stimulation...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(76)80020-8
更新日期:1976-12-01 00:00:00
abstract::Studies on cardiac conduction disorders and pacemaker tachycardias are usually conducted in patients because the phenomenon of ventriculoatrial (retrograde) conduction resulting from ectopic beats and pacing the ventricles has only been reported in humans. This study was conducted to characterize the ventriculoatrial ...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(84)90621-5
更新日期:1984-08-01 00:00:00
abstract:BACKGROUND:Perflenapent injectable emulsion is a newer echocardiographic contrast agent that provides chamber opacification and improved endocardial border delineation. In >1000 patients tested, adverse effects have been minimal. However, previous studies have included few patients with congestive heart failure (CHF) o...
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:10.1067/mhj.2000.106612
更新日期:2000-06-01 00:00:00
abstract::Although cost estimates for acute myocardial infarction are necessary for decisions about allocating scarce resources, there is a relative paucity of studies that estimate these costs across the entire spectrum of hospitals in actual clinical practice. This study sought to determine the correlates of in-hospital costs...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/s0002-8703(98)70331-x
更新日期:1998-03-01 00:00:00
abstract::The aim of this prospective study was to compare the short-term reproducibility of the signal-averaged ECG (SAECG) with three analysis techniques, conventional time-domain analysis, spectral-temporal mapping (STM), and spectral-turbulence analysis (STA), in a large series of normal subjects and patients with acute myo...
journal_title:American heart journal
pub_type: 杂志文章
doi:10.1016/0002-8703(95)90202-3
更新日期:1995-11-01 00:00:00
abstract:BACKGROUND:The increasing burden of cardiovascular disease (CVD) in low- and middle-income countries is largely driven by the increasing prevalence of hypertension, diabetes, and tobacco use. We hypothesize that the utilization of community health workers (CHWs) to screen for and manage these 3 determinants of CVD in a...
journal_title:American heart journal
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.ahj.2016.10.027
更新日期:2017-03-01 00:00:00
abstract::Tolerance to prolonged nitroglycerin (NTG) may be due to drug-induced intravascular expansion. To test the hypothesis that concomitant diuretics may reduce volume expansions and thus prevent NTG tolerance, we studied 23 healthy volunteers randomized to hydrochlorthiazide or placebo before and during 74-hour continuous...
journal_title:American heart journal
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1016/0002-8703(95)90361-5
更新日期:1995-09-01 00:00:00