Results 191 to 200 of about 177,330 (252)

Isovolumic relaxation time varies predictably with its time constant and aortic and left atrial pressures: Implications for the noninvasive evaluation of ventricular relaxation

American Heart Journal, 1992
The isovolumic relaxation time (IVRT) is an important noninvasive index of left ventricular diastolic function. Despite its widespread use, however, the IVRT has not been related analytically to invasive parameters of ventricular function. Establishing such a relationship would make the IVRT more useful by itself and perhaps allow it to be combined ...
J. Luis Guererro, Frank A. Flachskampf, Arthur E. Weyman, Robert A. Levine, Michael H. Picard, Chunguang Chen, James D. Thomas   +6 more
semanticscholar   +5 more sources

Quantification of incomplete left ventricular relaxation: relationship to the time constant for isovolumic pressure fall

European Heart Journal, 1980
We initially found that the fall in left ventricular pressure during isovolumic relaxation is exponential and therefore characterized by a time constant (T). To the extent that isovolumic pressure fall reflects myocardial events during relaxation, T indexes the time course of relaxation of the left ventricle.
J. L. Weiss, Myron L. Weisfeldt, J. T. Frederiksen, Frank C.P. Yin   +3 more
semanticscholar   +5 more sources

Isovolumic relaxation time corrected for heart rate has a constant value from infancy to adolescence

Journal of the American Society of Echocardiography, 2003
Isovolumic relaxation time (IVRT) is a valuable adjunct to Doppler flow signals measured at mitral valve level for proper interpretation of left-ventricular diastolic performance. Few data exist on reference values in the pediatric age group. Moreover, routine evaluation of IVRT in patients with limited cooperation ability is impeded by the common ...
Lothar Schmitz, Martin B.E. Schneider, Peter E. Lange   +2 more
semanticscholar   +5 more sources

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Right ventricular myocardial isovolumic relaxation time and pulmonary pressure

Clinical Physiology and Functional Imaging, 2005
SummaryAims:  Non‐invasive assessment of pulmonary artery systolic pressure (PASP) has several limitations. As previously described by Burstin, the right ventricular (RV) isovolumic relaxation time (IVRt) is sensitive to changes in PASP. We therefore compared RV myocardial IVRt, derived by Doppler tissue imaging (DTI), with simultaneously measured ...
Elsadig Kazzam, Elsadig Kazzam, Anders Waldenström, Per Lindqvist, Gerhard Wikström   +4 more
openaire   +4 more sources

Isovolumic relaxation time: Comparison of Doppler methods

Heart, Lung and Circulation, 2003
Paul Calafiore, Diane M. Jackson
semanticscholar   +4 more sources

The Evaluation of Pulmonary Hypertension Using Right Ventricular Myocardial Isovolumic Relaxation Time

Journal of the American Society of Echocardiography, 2005
Right ventricular (RV) blood pool-derived isovolumic relaxation time (IVRT) correlates well with systolic pulmonary arterial pressure (PAP). However, because of complex parameter derivation, the method is rarely used. The aim of this study was to validate the measurement of myocardial velocity imaging-derived RV IVRT (IVRT') against invasively measured
George R. Sutherland, Tomas Palecek, Frank Rademakers, Lieven Herbots, Virginija Dambrauskaite, Piet Claus, Jan D'hooge, Bart Bijnens, Marion Delcroix   +8 more
openaire   +4 more sources

Effect of verapamil on left ventricular isovolumic relaxation time and regional left ventricular filling in hypertrophic cardiomyopathy

The American Journal of Cardiology, 1980
Hypertrophic obstructive and nonobstructive cardiomyopathy are often associated with an abnormal prolonged left ventricular isovolumic relaxation time and a disturbed left ventricular filling pattern [1–5]. Recent experimental studies revealed that calcium antagonists may improve impaired left ventricular relaxation caused by ischemia or hypoxia [6, 7].
Frank Sonntag, Walter Bleifeld, Detlef G. Mathey, Peter Hanrath, Peter Kremer   +4 more
openaire   +3 more sources

Myocardial relaxation IV: mechanical determinants of the time course of left ventricular pressure decline during isovolumic relaxation

European Heart Journal, 1980
Relaxation of isolated mammalian cardiac muscle is known to be influenced by loading conditions, but the mechanical determinants of relaxation velocity in the intact heart are not well defined. Accordingly, we measured the time constant (T) of left ventricular (LV) isovolumic pressure decline during descending and ascending thoracic aorta cross-clamp ...
Dan Adam, William H. Gaasch, A. S. Blaustein   +2 more
openaire   +4 more sources

Logistic Time Constant of Isovolumic Relaxation Pressure–Time Curve in the Canine Left Ventricle

Circulation, 1995
Background The time constant of left ventricular (LV) relaxation derived from a monoexponential model has been widely used as an index of LV relaxation rate or lusitropism, although this model has several well-recognized problems. In the present study, we proposed a logistic model and derived a “logistic” time constant (
Shingo Yasuhara, Hiroyuki Suga, Miyako Takaki, Junichi Araki, Hiromi Matsubara   +4 more
openaire   +4 more sources

Measurement of ventricular relaxation

Journal of Pharmacological Methods, 1989
The time constant (T) is commonly used for representing the isovolumic fall in left ventricular pressure (LVP) because the isovolumic fall is monoexponential under most circumstances. However, the determination of T is cumbersome due to the requirement of a set of LVP versus time values in fitting a monoexponential function.
K. Lee
openaire   +4 more sources