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At least 253 records · Page 14Linked to original sources
PubMed1988

Cardiac function in open-chest dogs after left to right ventricular shunting and right coronary artery occlusion.

Patients with acquired ventricular septal defect (VSD) after myocardial infarction have a particularly bad prognosis if right ventricular function is severely impaired. The significance of an ischaemic right ventricular free wall on cardiac function during interventricular shunting was examined in open-chest dogs. An external interventricular shunt could be opened and closed at will, and by occlusion of the right coronary artery (RCA), a part of the right ventricular free wall was rendered ischaemic. Aortic flow decreased by 8 +/- 2% when the shunt was opened in the presence of a normal right ventricle, and by 16 +/- 2% (difference: P less than 0.05) in the presence of right ventricular ischaemia. Aortic flow fell by 19 +/- 3% when the RCA was occluded. Right ventricular dyskinesia was demonstrated after occlusion of RCA, by recording segment lengths in the right ventricular free wall. The dyskinesia was aggravated when the shunt was opened. The left ventricle exerted a 'negative' work on the ischaemic right ventricular free wall. Retention of blood in the right ventricle, with a subsequent decline in left ventricular filling and an almost unchanged interventricular shunting of blood, explain why aortic flow fell more when the shunt was opened in the presence of right ventricular ischaemia.

Animals↗
PubMed1991

Hypertonic saline dextran resuscitation fails to improve cardiac function in neonatal and senescent burned guinea pigs.

Our previous studies suggested that the greater diminution in burn-induced cardiac contractile function which occurs in young and elderly subjects compared with adult subjects is related to differences in intracellular calcium availability to the myofilaments. We recently showed that improved cardiac function after hypertonic saline dextran (HSD) resuscitation from burn injury in adults was related to enhanced intracellular calcium content. In the study presented here, 126 hearts isolated from neonatal, adult, and senescent guinea pigs were used to evaluate age-related differences in cardiac contractile response to HSD resuscitation from burn injury. Scald burn was induced in 30 adult, 18 neonatal, and 30 senescent guinea pigs; within each age group, half of the burned animals were resuscitated with lactated Ringer's (Parkland formula, 4 mL/kg/% burn for 24 hours); half received an initial bolus of HSD (4 mL/kg, IV) plus lactated Ringer's (1 mL/kg/% burn for 24 hours). An additional 16 animals from each age group served as sham burn controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Pharmacologic interventions for the neonate with compromised cardiac function.

The developmental aspects of myocardial performance must be considered when pharmacologic agents are used to support the neonate with compromised cardiac function. Neonatal cardiovascular function is characterized by a limited preload reserve, decreased ventricular compliance, limited contractile reserve, and CO that is primarily dependent on the HR. Nurses caring for these neonates need a baseline understanding of normal cardiovascular physiology to evaluate the effectiveness of pharmacologic interventions to augment CO. Neonatal nurses play a pivotal role in the therapeutic management of pharmacologic interventions to provide safe, high quality care for the sick neonate.

Cardiovascular Agents↗
PubMed1986

The effects of burn injury and fluid resuscitation on cardiac function in vitro.

The effects of a 30% full-thickness total body surface area scald burn on in vitro mechanical cardiac function was studied in Sprague-Dawley rats. The findings were a 50% decrease in tension development and velocities of contraction and relaxation, when papillary muscle functions from sham and unresuscitated burned animals were compared. Fluid resuscitation synchronous with burning completely reversed the defects in papillary muscle function. This defect in function was partially transferable to normal muscles incubated in serum from burned rats.

Animals↗
PubMed1984

Disturbed cardiac function possibly associated with mianserin therapy.

Two patients, who were receiving therapy with mianserin for depressive disorders, developed signs of disturbed cardiac function which resolved after mianserin therapy was discontinued. One of the patients also developed hypokalaemia which was probably caused by the drug. It is felt that these side effects warrant further research.

Aged↗
PubMed1987

Pulsed Doppler and two-dimensional echocardiography: comparison of halothane and isoflurane on cardiac function in infants and small children.

The combination of two-dimensional and pulsed Doppler echocardiography was used to measure determinants of cardiac function in 20 ASA physical status I infants and small children (9 days-32 months of age) during equipotent halothane (n = 10) or isoflurane (n = 10) anesthesia in oxygen. Five sets of cardiovascular data were recorded in each patient. In the awake, unmedicated state prior to induction, at three different anesthetic levels, 0.75, 1.0, and 1.25 MAC (corrected for age) and a final measurement repeated at 1.25 MAC after the intravenous infusion of 15 ml X kg-1 of Lactated Ringers solution. The study was completed prior to intubation and surgery. Results are expressed as mean +/- SEM. Isoflurane and halothane decreased mean blood pressure from the awake level (isoflurane 76.6 +/- 2.3 to 60.6 +/- 3.1 mm, halothane 72.2 +/- 3.9 to 60.6 +/- 3.1 mm at 1.25 MAC). Isoflurane increased heart rate at all anesthetic levels (128.7 +/- 4.2 to 142.5 +/- 6.0 beats/min at 0.75 MAC). Halothane decreased heart rate at 1.25 MAC (124.6 +/- 4.6 to 119.4 +/- 3.5 beats/min). Isoflurane and halothane decreased cardiac index at 1.25 MAC. Stroke volume index decreased at 1.0 and 1.25 MAC with both isoflurane (36.9 +/- 3.8 to 30.2 +/- 3.5 ml/m2) and halothane (32.7 +/- 2.5 to 28.9 +/- 2.5 ml/m2). Ejection fractions also decreased significantly at 1.0 and 1.25 MAC in both groups of patients (22 +/- 6% at 1.25 MAC halothane and 28 +/- 8% at 1.25 MAC isoflurane).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1984

Evaluation of size and dynamics of the inferior vena cava as an index of right-sided cardiac function.

To define normal criteria of size and dynamics of the inferior vena cava (IVC) and its clinical value in assessing right-sided cardiac function, 2-dimensional (2-D) and M-mode echocardiography (echo) were performed in 175 subjects, who were classified into 3 groups: group 1-80 normal subjects; group IIA--65 patients with documented right-sided cardiac disease, and group IIB--30 patients with cardiac disease but no right-sided abnormality. The IVC was adequately imaged in 175 of 185 subjects (95%). There was good correlation between M-mode and 2-D echo (r = 0.84) and long- and short-axis (r = 0.88) measurements. The IVC diameter during expiration was: group 1-9 to 28 mm (mean 18.2 +/- 4.6); group IIA--15 to 40 mm (mean 23.1 +/- 4.8) and group IIB-8-24 mm (mean 15.6 +/- 3.7). Collapsibility index (inspiratory decrease in diameter) was: group I-37 to 100% (mean 55.8 +/- 15.9); group IIA--0 to 39% (mean 13.5 +/- 10.5); and group IIB--44 to 100% (mean 60.4 +/- 13.1). A and V waves could be measured in 120 of 151 cases (79%). Both A and V waves were less than 125% of its diameter in group I. The A wave was absent in 34 patients; 30 (88%) were in atrial fibrillation. Among 8 patients with tricuspid regurgitation, 5 (63%) had V waves greater than 125%. There was no correlation between diameter or collapsibility index and age, sex, rhythm or body surface area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Augmentation of cardiac function by elevation of intrathoracic pressure.

We studied the cardiovascular effects of increasing intrathoracic pressure in an acute pentobarbital-anesthetized canine model of acute ventricular failure induced by large doses of propranolol. Left ventricular (LV) function curves were generated by volume loading from LV filling pressures of 5-20 Torr. The animals were ventilated by using intermittent positive-pressure ventilation with large tidal volumes (30 ml/kg). Chest and abdominal pneumatic binders were used to increase intrathoracic pressure. When compared with the control state, acute ventricular failure was associated with a decrease in the slope of the LV function curves (P less than 0.01). After binding the increase in intrathoracic pressure (1.1 +/- 1.6 to 12.1 +/- 2.4 Torr, P less than 0.01) was associated with an improvement in both right ventricular and LV function. Our study demonstrates that in this model of acute ventricular failure, increasing intrathoracic pressure improves cardiac function. We postulate that this observed improvement with increased intrathoracic pressure is due to reduced LV wall stress in a manner analogous to that seen with arterial vasodilator therapy in congestive heart failure.

Acute Disease↗
PubMed1987

Cardiac function: evaluation with fast-echo MR imaging.

Magnetic resonance (MR) imaging of the heart has, to date, been limited in its ability to evaluate cardiac function. The authors have implemented a technique for functional assessment of the heart using shorter echo times than those generally used for conventional spin-echo imaging. With these short echo times, multiple images can be obtained in a multisection mode approximately within the isovolumetric phases of the cardiac cycle. This permits a pair of image stacks to be obtained, one in end systole and the other in end diastole. With the use of a modified Simpson rule, left ventricular volume and ejection fraction were calculated and compared with results obtained from contrast material-enhanced ventriculography. Preliminary results indicate that this method has promise for the evaluation of a variety of functional parameters in the heart. The short acquisition times for this functional study permit it to be combined with a tissue characterization study within the time constraints of a clinical MR imaging session.

Heart Function Tests↗
PubMed1989

[Relationship between left atrial diameter and cardiac function in myocardial infarction--assessment of left ventricular end-diastolic pressure by the left atrial index].

To study the assessment of cardiac function in acute myocardial infarction (AMI), we measured left atrial diameter, left ventricular end-diastolic pressure (LVEDP), pulmonary capillary wedge pressure (PCWP), ejection fraction (EF) in 20 patients with acute myocardial infarction. Left atrial diameter was measured using echocardiography and was expressed as left atrial index (LAI, mm/m2) dividing by body surface area. LAI in AMI was 21.3 +/- 2.7 mm/m2 and significantly larger than LAI in normal subject (19.9 +/- 2.0 mm/m2) (p less than 0.05), In AMI, LVEDP was 13.3 +/- 3.4 mmHg, PCWP was 9.0 +/- 2.8 mmHg and EF was 52.3 +/- 14.8%, Relationship (r value) between LAI and LVEDP (r = 0.70, p less than 0.001, y = 0.87 x-5.4 x; LAI, y; LVEDP) was greater than PCWP and LVEDP (r = 0.60, p less than 0.01). LVEDP calculated from LAI using this method was directly measured LVEDP directly measured +/- 2.4 mmHg. In 9 patients, LAI was larger than 20.9 mm/m2, in 8 patients of them LVEDP was higher than 13 mmHg. In 11 patients LAI was smaller than 20.9 mmHg, only in 2 of them LVEDP was lower than 13 mmHg. It concluded that sensitivity was 88.9%, specificity was 81.8%, accuracy was 85.0%. Relationship between LAI and PCWP (r = 0.30), LAI and EF (r = -0.36) were not significant. We can measure LAI repeatedly in AMI non-invasively, and predict LVEDP. Thus, the measurement of LAI is useful in treatment of AMI.

Adult↗
PubMed1978

Effects of 5-([2-(diethylamino)-ethyl]amino)-3-phenyl-1,2,4-oxadiazole dihydrochloride (DEPO) on cardiac functions and myocardial metabolism of the dog.

Effects of 5-([2-(diethylamino)-ethyl]amino)-3-phenyl-1,2,4-oxadiazole (DEPO) on cardiac functions and myocardial metabolism were examined using the heart in vivo and the isolated perfused heart of dogs. In the heart in vivo DEPO i.v. produced dose-dependent decreases in coronary perfusion pressure (PP), heart rate (HR), left ventricular pressure (LVP), dP/dt max of LVP and coronary vascular resistance (VR). DEPO i.c. dose-dependently increased left circumflex coronary flow (LCCF) and decreased PP, LVP and dP/dt max of LVP, but did not change HR. In the isolated perfused heart, DEPO induced a marked increase in coronary blood flow (CBF) and depressed HR and myocardial contractile force. Myocardial oxygen consumption and myocardial redox potential were not significantly changed. DEPO could not modify the effects of isoproterenol, adenosine and reactive hyperaemia on the heart. The results suggest that DEPO may have a coronary vasodilating action and some direct inhibitory actions on the heart.

Adenosine↗
PubMed1990

Cardiac function and morphology of Hanford miniature swine and Yucatan miniature and micro swine.

The use of miniature swine in biomedical research is increasing; however, a comparison of cardiac function and morphology between strains has yet to be characterized. The purpose of this project was to examine comprehensive hemodynamics and cardiac morphology of three groups of ten normal, 4 months old, age-matched Yucatan miniature (MINI) pigs, Yucatan micropigs (MICRO) and Hanford (HAN) miniature pigs, 5 males and five females per group. Closed chest cardiac catheterization under equivalent conditions was performed followed by post mortem cardiac morphometry. Mean arterial pressure was significantly greater in the Hanford group when compared to both the minipig and micropig pigs (HAN: 89 +/- 4; MINI: 48 +/- 3; MICRO: 53 +/- 2 mmHg). Pulmonary vascular resistance was significantly different between the three groups (HAN: 9 +/- 1; MINI: 60 +/- 12; MICRO: 111 +/- 29 dyne x sec/cm x m2). The Hanford strain had a significantly smaller heart weight to body weight ratio than the other two groups (HAN: 4.6 +/- 1.0; MINI: 5.7 +/- 0.1; MICRO: 5.5 +/- 1.0). Variations in cardiovascular parameters occur among these strains and should be considered when constructing experimental designs.

Animals↗
PubMed1991

Effects of regression of left ventricular hypertrophy following atenolol or bunazosin therapy on ischemic cardiac function and myocardial metabolism in spontaneously hypertensive rats.

The effects of regression of left ventricular hypertrophy following atenolol and bunazosin therapy on ischemic cardiac function and myocardial metabolism in spontaneously hypertensive rats (SHR) were studied. Atenolol (50 mg/kg/day) and bunazosin (5 mg/kg/day) were administered to SHR from 19 to 26 weeks of age, whereas tap water was given to control SHR and normotensive Wistar-Kyoto rats (WKY). Both atenolol and bunazosin significantly decreased arterial blood pressure and significantly decelerated the increase in left ventricular weight in SHR. At the end of the long-term treatment, hearts were removed and perfused by the working heart technique for 15 min, and then global ischemia was induced for either 10 or 30 min. The ischemic heart was reperfused for 30 min. The pressure-rate product and the extent of recovery of the coronary flow after reperfusion following 30 min of ischemia in the bunazosin-treated SHR were significantly higher than those in the control SHR and the atenolol-treated SHR. The levels of adenosine triphosphate (ATP), creatine phosphate (CrP), and energy charge potential in the SHR heart reperfused after 30 min of ischemia were significantly lower than those in the reperfused WKY. Both atenolol and bunazosin improved the restoration of ATP and CrP in SHR after reperfusion following 30 min of ischemia. In conclusion, antihypertensive therapy with either atenolol or bunazosin was effective in preventing cardiac hypertrophy and ischemic damage caused by different mechanisms. Factors resulting from stimulation of the cardiac alpha 1 adrenoceptor may play an important role in the development of hypertensive cardiac hypertrophy, just as factors resulting from stimulation of the beta 1-adrenoceptor do.

Adenosine Diphosphate↗
PubMed1991

A computer-assisted image processing method for determining relative cardiac function in the chick embryo.

The general objective of this study was to develop a noninvasive method for efficiently and reproducibly determining relative cardiac function parameters in the chick embryo. The specific objectives of the study were 1) to develop several methods for computer-assisted image processing and quantitation of relative intraventricular blood volumes in the 3-day-old embryonic chick heart and 2) to compare methods for precision and with a previously established manual processing method. Images of the embryonic chick heart in ovo were recorded on videocassette tape, digitized, and enhanced by computer-aided histogram equalization. The area occupied by blood within the common ventricle was extracted by region-growing and spurious region removal algorithms and defined by the determination of edge-pixel coordinates. Edge-pixel coordinates of the longitudinal and transverse axes of the common ventricular blood region were located by three different methods, the lengths of the axes calculated, and volumes computed from the equation for determining volume of a prolate spheroid. Twenty-five images of the embryonic heart were randomly selected and processed. Volumes were calculated with each of the three methods on six different occasions. A coefficient of variation was calculated for each method. The intraobserver mean coefficient of variation for each method was 7.4%. When a 2-way ANOVA was conducted, mean coefficients of variation did not differ significantly for the three methods. However, computer processing (in addition to significantly reducing the time required to generate data) reduced the coefficient of variation observed in manual processing by 56.5%.

Analysis of Variance↗
PubMed1983

Effects of acetate and bicarbonate hemodialysis on cardiac function in chronic dialysis patients.

Previous studies have suggested that acetate hemodialysis causes myocardial depression. This study examines the acute effects of hemodialysis using, alternately, bicarbonate and acetate in the dialysate, on cardiac function in ten patients. These patients were also studied during acetate dialysis using a large surface area (SA) dialyzer. Each patient was dialyzed for 4 hr with: (1) 1.0 m2 SA dialyzer and bicarbonate dialysate; (2) 1.0 m2 SA dialyzer and acetate bath, and; (3) 2.5 m2 SA dialyzer and acetate dialysate. All studies were performed during isovolemic dialysis to separate the effects of changes in cardiac filling volume with hemodialysis, from changes in myocardial contractility. Myocardial function, as assessed by pre- and postdialysis echocardiographically derived fractional shortening (Fs) and mean velocity of circumferential shortening (VCF), improved (P less than 0.05) to the same extent, after all three dialysis treatments. This occurred despite greater increases (P less than 0.002) in pH and bicarbonate after bicarbonate dialysis and decreases (P less than 0.05) in PO2, PCO2 and bicarbonate after acetate dialysis with 2.5 m2 SA dialyzer. These results indicate that diffusive dialysis with both acetate and bicarbonate dialysate improves myocardial function and do not support the view that acetate influx during dialysis can lead to myocardial depression.

Acetates↗
PubMed1977

Pacing techniques in assessing cardiac function in the horse.

The problem of transitory cardiac arrhythmias in equidae is discussed particularly with regard to the referral of suspect cases to specialist institutions for second opinion. Recently developed electro-stimulation techniques designed to uncover problem arrythmias, are briefly described and their potential in the analysis of cardiac electrical function under varying conditions is reviewed. The author cautions on the too rapid evaluation of the techniques for this purpose while remaining optimistic of the potential of electro-stimulation in the objective analysis of cardiac electric parameters.

Animals↗