OBJECTIVES The aim of this study was to define an index that can differentiate normal from ischemic myocardial segments that exhibit postsystolic shortening (PSS). BACKGROUND Identification of ischemia based on the reduction of regional systolic function is sometimes challenging because other factors such as normal nonuniformity in contraction between segments, tethering effect, pharmacologic...

We studied the effects of coronary occlusion and of subsequent ouabain administration on regional myocardial function, flow, and electrograms in 14 conscious dogs. Coronary occlusion resulted in a graded loss of regional function as reflected by measurements of segment length (SL), velocity of SL shortening and myocardial "work" from the normal to severely ischemic zones, along with graded flow...

Instantaneous left ventricular dynamics were measured from cineradiographs utilizing implanted tantalum coils as myocardial site markers in the orthotopically transplanted canine heart. Four parameters of myocardial synergy were obtained: mean shortening, anisotropy of contraction, mean time to half shortening, and asynchrony of contraction. Estimates of end diastolic volume, end systolic volum...

After acute myocardial infarction there is a shortening of the QS2 interval and the ejection time. The pre-ejection time is either normal or prolonged. After the stage of maximum shortening of the QS2 interval and ejection time, there is a progressive improvement towards the normal. In this study there was no correlation between the shortened QS2 interval and ejection time, and the level of uri...

The proinflammatory cytokine tumor necrosis factor-alpha (TNF-α) is associated with myocardial dysfunction observed in sepsis and septic shock. There are two fundamental components to this dysfunction. (1) systolic dysfunction; and (2) diastolic dysfunction. The aim of these experiments was to determine if any aspect of whole-heart dysfunction could be explained by alterations to global intrace...

There is no direct evidence to indicate that pump dysfunction in a dilated chamber reflects the impact of chamber dilatation rather than the degree of intrinsic systolic failure resulting from myocardial damage. In the present study, we explored the relative roles of intrinsic myocardial systolic dysfunction and chamber dilatation as mediators of left ventricular (LV) pump dysfunction. Administ...

OBJECTIVES We sought to determine whether left ventricular (LV) postsystolic shortening in the region of acute myocardial infarction (MI) predicts functional recovery after primary angioplasty. BACKGROUND Previous studies in experimental animals have shown that postsystolic shortening during temporary coronary occlusion predicts functional recovery after reperfusion. METHODS Contrast ventri...

BACKGROUND Noninvasive predictors of important outcomes after valve replacement for mitral regurgitation have not been examined in a rheumatic population (in whom the results of valve repair are suboptimal) in the era of chordal preservation. Timing of valve replacement thus remains a difficult question in rheumatic mitral regurgitation. METHODS AND RESULTS Of 278 patients followed after valv...

Sodium pentobarbital (PB), 30 mg/kg, iv, was administered to 30 conscious dogs instrumented for measurement of cardiac output and regional blood flow distribution, left ventricular (LV) diameter, LV pressure, dP/dt, and dD/dt, i.e., velocity of myocardial fiber shortening. Ventilation was controlled during anesthesia to maintain arterial blood gases at control values for conscious dogs. The ane...