1,720,963 research outputs found
What is the actual contribution of atrioventricular plane displacement to left ventricular stroke volume?
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Adaptive and maladaptive cardiac hypertrophy: what is the effective role of heat shock transcription factor 1?
No full textComment on
Upregulation of heat shock transcription factor 1 plays a critical role in adaptive cardiac hypertrophy
Letter by Ballo et al regarding article, "Serial biomarker measurements in ambulatory patients with chronic heart failure: the importance of change over time"
No full textComment on
Serial biomarker measurements in ambulatory patients with chronic heart failure: the importance of change over time. [Circulation. 2007
Laboratory-based versus non-laboratory-based CVD risk analysis.
No full textLetter
Comment on
Laboratory-based versus non-laboratory-based method for assessment of cardiovascular disease risk: the NHANES I Follow-up Study cohort. [Lancet. 2008
Letter by Bocelli et al regarding article, "A novel method of expressing left ventricular mass relative to body size in children"
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Left ventricular longitudinal systolic dysfunction is an independent marker of cardiovascular risk in patients with hypertension.
No full textBACKGROUND: To explore the prognostic value of left ventricular (LV) longitudinal systolic dysfunction in patients with hypertension.
METHODS: In 156 hypertensive subjects, LV longitudinal systolic function was assessed by echocardiographic measurement of M-mode left atrioventricular plane displacement (AVPD) and Tissue Doppler (TD)-derived mitral annulus peak systolic velocity (Sm). Patients were followed for development of the following cardiovascular events: congestive heart failure requiring hospitalization, new-onset angina, nonfatal myocardial infarction, coronary revascularization procedures, transient ischemic attack, nonfatal stroke, and cardiovascular death.
RESULTS: Over a follow-up of 23.3 +/- 5.4 months, 24 patients had 29 events. Both longitudinal systolic indices were predictive of outcome (hazard ratios: AVPD, 0.24, P < 0.001; Sm, 0.22; P < 0.001). AVPD < or = 11.4 mm (75.0% sensitivity and 53.8% specificity) and Sm < or = 8.9 cm/s (79.2% sensitivity and 61.4% specificity) were identified as the best cutoffs for the prediction of cardiovascular events (area under curve: AVPD, 0.66, P < 0.01; Sm, 0.71; P < 0.0001). Compared to conventional indices of circumferential systolic function, AVPD and Sm showed similar overall diagnostic performance, but higher sensitivity and lower specificity. Coexistence of longitudinal and circumferential systolic dysfunction was associated with the worst prognosis (P < 0.0001). Multivariate analysis confirmed an independent association of longitudinal indices with clinical outcome, incremental to circumferential systolic impairment, and other confounding variables.
CONCLUSIONS: Longitudinal systolic dysfunction is an independent marker of cardiovascular risk in hypertensive patients. Despite similarity in predictive accuracy, longitudinal indices are more sensitive but less specific than circumferential indices for the prediction of cardiovascular events in these subjects
Concordance between M-mode, pulsed Tissue Doppler, and colour Tissue Doppler in the assessment of mitral annulus systolic excursion in normal subjects.
No full textAbstract
AIMS: M-mode left atrioventricular plane displacement (AVPD) correlates with Tissue Doppler (TD) peak systolic annular velocity in healthy individuals. This approach is biased by several interacting factors related to the structural complexity of mitral annulus physiology, including the different dimensional values of measures, the confounding effect of isovolumic motions, and the spectral thickness of pulsed TD envelope. We sought to analyze the effective concordance between techniques in the assessment of systolic annular excursion.
METHODS AND RESULTS: In 92 healthy subjects (age 60.5 +/- 18.6, 43.5% women), systolic AVPD was measured after exclusion of isovolumic components using three techniques: (i) M-mode; (ii) temporal integration of pulsed TD systolic wave; and (iii) colour TD-derived tissue tracking. Close correlations of M-mode AVPD with pulsed TD velocity-time integral (VTI) (R = 0.90, P < 0.0001) and colour TD AVPD (R = 0.86, P < 0.0001) were found. However, M-mode AVPD underestimated pulsed TD VTI (mean error -5.1 +/- 1.7 mm) and overestimated colour TD AVPD (mean error 3.4 +/- 1.3 mm). The concordance between M-mode and pulsed TD increased after adjustment for spectral dispersion of pulsed TD instantaneous velocities (mean error 0.1 +/- 1.1 mm).
CONCLUSION: Despite strict correlations exist between M-mode and TD in the assessment of mitral annulus systolic excursion, the effective concordance between techniques is sub-optimal
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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