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At least 55 records · Page 3Linked to original sources

PubMed1989

Left ventricular function in experimental volume overload hypertrophy.

Left ventricular function in volume overload hypertrophy is controversial. In humans, chronic severe volume overload eventually results in left ventricular dysfunction; paradoxically, experimental volume overload hypertrophy has nearly always been associated with normal left ventricular function. However, in most cases, experimental volume overload hypertrophy has either been mild or only present for a short duration. To help resolve the issue of contractile function in volume overload hypertrophy, we examined ventricular function in a recently described model of severe chronic experimental mitral regurgitation. Left ventricular function was measured before and 3 mo after the creation of severe mitral regurgitation (averaged regurgitant fraction 0.64 +/- 0.04). At 3 mo end-diastolic volume had increased from 78 +/- 5 to 114 +/- 7 ml (P less than 0.01). Significant left ventricular hypertrophy had occurred with an increase in the left ventricular weight-to-body weight ratio from 3.84 +/- 0.2 to 5.22 +/- 0.2 (P less than 0.01). All indicators of left ventricular function (ejection fraction, the end ejection stress-volume relationship, this relationship corrected for eccentric hypertrophy, and mean velocity of circumferential fiber shortening at a common stress) were reduced at 3 mo. Our study produced 64% volume overload which was maintained for 3 mo at which time there was a 36% increase in left ventricular mass. This amount of volume overload of this duration produced significant left ventricular dysfunction.

Animals↗

PubMed1977

Coronary reserve and right ventricular function in awake newborn lambs with persistent right ventricular hypertension.

Right ventricular function curves as measured by right ventricular stroke work were normal in all control lambs, whereas three of five lambs with banded pulmonary arteries had relatively flat curves. Left ventricular function was similarly normal in the control group as compared to a near zero slope function curve in the banded group. Regional myocardial blood flow to the septum and right and left ventricles was similar in control and banded lambs. At rest right ventricular coronary vascular resistance was lower in the banded than in the control group and decreased in both groups during both isoproterenol and dextran stress states. In general, both groups had a similar ratio of right to left ventricular oxygen supply to demand ratio. These results show first that there is minimal, if any, biventricular functional reserve in lambs with persistent right ventricular hypertension, and second, that there is substantial coronary vascular reserve in both normal and banded groups.

Animals↗

PubMed1991

[Cardiac function during exercise in patients with coronary bypass surgery assessed by continuous ventricular function monitoring].

The response of left ventricular function during exercise and recovery after exercise was assessed in 52 patients with coronary artery bypass surgery by means of a radionuclide continuous ventricular function monitor. This system consists of 2 radionuclide detectors, recorder and a computer. After the equilibration of 20 mCi technetium 99m-labeled autologaous red blood cells into the intravascular space, the beat by beat radionuclide data were summed for 20-sec intervals to measure left ventricular ejection fraction (EF). Before surgery, the mean EF decreased with exercise from 51 +/- 9% to 45 +/- 11% (p less than 0.001). Cardiac response was divided into 4 types according to the profiles of the EFs during exercise. In 6 patients, EF continued to increase until maximal exercise (type A). In 10 patients, EF initially increased and then decreased in late exercise stages (type B). In 9 patients, EF did not change significantly during exercise (type C). In 27 patients, EF decreased throughout exercise (type D). After surgery, the mean EF increased with exercise from 53 +/- 10% to 60 +/- 13% (p less than 0.001). Thirty-five patients showed type A, 9 type B, 5 type C, and 3 type D. Two type D and 5 type B patients had occluded grafts or ungrafted coronary arteries. Four patients with complete revascularization including an internal thoracic artery and saphenous vein grafts showed type B. Three patients with extensive infarction and poor left ventricular function showed type C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1975

The angiotensin infusion test as a method of evaluating left ventricular function.

Fifteen patients had left ventricular function measured by the angiotensin infusion method. Seven patients had no evidence of heart disease, and eight patients had angina pectoris and coronary arteriographic evidence of coronary disease without congestive heart failure. During angiotensin infusion, those patients without heart disease had a decrease in cardiac index (average, 0.63 L. per minute per square meter) and a decrease in heart rate (average, 12 beats per minute.) The ventricular function curve had a poor SWI response in four of the seven subjects. The patients with coronary artery disease also had a reduction in cardiac index during angiotensin (average, 0.44 L. per minute per square meter) and the heart rate was unchanged in four subjects, increased in two subjects, and decreased in two subjects. Six of the subjects had flat or descending slopes on the function curve, and in one subject there was only a very gradual ascending slope. Many of the curves of both groups looked similar so that the function curves did not differentiate between those patients with or without heart disease. The mechanism for production of bradycardia, reduction of cardiac output, and depressed function curves with angiotensin is multifactorial, but is probably due to the baroreceptor reflex response, the increase in coronary artery resistance, and possible to the direct effect of increased left ventricular afterload itself. The ventricular response to angiotensin is so variable that the angiotensin infusion method of evaluating ventricular function is not reliable.

Adolescent↗

PubMed1977

Effect of sodium bicarbonate on canine left ventricular function.

Left ventricular performance was evaluated in seven canine right heart bypass preparations during and after the intraauricular administration of sodium bicarbonate (100 ml, 1100 Osm, 60 mEq). Under conditions of constant cardiac input and left ventricular volume, sodium bicarbonate produced mild and brief left ventricular depression, as manifested by a decline of left ventricular dp/dt with simultaneous rise of left ventricular end-diastrolic and left atrial pressures. These findings occurred as aortic impedance fell. Identical results accrued in paced and unpaced preparations. The data lends credence to the proposition that a sudden rise in blood pCO2 produces increased transport of CO2 across the cardiac membranes with intracellular acidosis. However, the data is also compatible with hyperosmolality induced contractile depression. Possible clinical implications are discussed.

Animals↗

PubMedDate not supplied

Left ventricular function during respiratory failure.

Indirect measures of left ventricular function were studied in seven patients with respiratory failure secondary to chronic obstructive pulmonary disease to determine if there were a relationship between left ventricular function and treatment of the pulmonary disease. All patients were studied during acute episodes while in respiratory failure having arterial Pco2 (Paco2) values greater than 49 torr with no clinical evidence of left ventricular failure. Indirect methods to evaluate left ventricular function included the use of the Swan-Ganz catheter for pulmonary capillary wedge pressure measurement, systolic time intervals, and cardiac output. There was improvement in left ventricular function with treatment of the respiratory failure manifested by decreases in the wedge pressure and pre-ejection period/left ventricular ejection time ratio, and an increase in the dp/dt/pulmonary capillary wedge pressure with treatment of the chronic obstructive pulmonary disease. The improvement in left ventricular function suggests that there is a depression of left ventricular function in respiratory failure. The depressed function improved with therapy of the lung disease without additional medication directed at cardiac function.

Adult↗

PubMedDate not supplied

Comparison of preoperative left ventricular function with postoperative left ventricular response to exercise in patients with chronic aortic regurgitation and aortic stenosis.

The relation between preoperative left ventricular (LV) systolic function at rest and postoperative LV response to exercise was assessed in 13 patients with aortic regurgitation (AR) and nine patients with aortic stenosis (AS). Preoperative end-systolic volume index (ESVI) and ejection fraction (EF) determined by LV angiography were compared with postoperative exercise-induced changes of LV fractional shortening (delta %FS) and mean velocity of fiber shortening (delta mVcf) assessed by echocardiography. Preoperative EF and ESVI in 13 patients with AR correlated well with postoperative delta %FS and delta mVcf. Similarly, preoperative EF and ESVI in nine patients with AS correlated well with postoperative delta %FS and delta mVcf. Our study demonstrated that preoperative LV systolic function in AR and AS patients closely reflected postoperative LV response to exercise. Preoperative smaller ESVI will be warranted to expect a favorably good postoperative LV response to exercise.

Adult↗

PubMed1976

Relative insesitivity of isovolumic phase indices in the assessment of left ventricular function.

1. The authors compared the sensitivity of the isovolumic phase indices (contractility indices) against LV function curves ("pump-function" indices) in assessing ventricular performance. 2. Certain modifications of the usual isovolumic phase indices, especially those introducing the concept of comparison of exercise with rest, seemed to us to be slightly more helpful in separating normal subjects from the patient with coronary artery disease or cardiomyopathies, but these differences were not striking when statistically evaluated, and could not be utilized in assessment of left ventricular function in individual patients. 3. The construction of left ventricular function curves, in our hands, yielded equally as satisfactory information and, in addition, was much simpler to perform. 4. It is concluded that contractility indices are relatively insensitive in the assessment of left ventricular function, and that they offer little advantage over "pump-function" indices for this purpose.

Angiocardiography↗

PubMed1990

Preservation of ventricular function by treatment of ventricular fibrillation with phenylephrine.

Epinephrine promotes resuscitation from ventricular fibrillation because of its peripheral vasoconstrictive effects. However, the beta-adrenergic effects of epinephrine may be detrimental because of the stimulation of myocardial oxygen demand. To test whether functional recovery from fibrillation in hearts treated with a selective alpha-adrenergic agent is greater than in hearts treated with epinephrine, ventricular fibrillation was induced in eight isolated dog hearts while coronary perfusion pressure was maintained at 30 mm Hg. In random order, epinephrine (5 micrograms/min), phenylephrine (50 micrograms/min) or no drug was infused for 5 min. The heart was then defibrillated, the drug infusion stopped and coronary perfusion pressure increased to 100 mm Hg. Coronary blood flow (ml/min per 100 g), arteriovenous oxygen difference (ml O2/dl) and myocardial oxygen consumption (ml O2/min per 100 g) measured after 4 min of ventricular fibrillation were greater with epinephrine (mean +/- SD 30.9 +/- 11.7, 17.5 +/- 1.6 and 5.4 +/- 1.9, respectively) than with phenylephrine (24.4 +/- 6.0, 15.7 +/- 2.6 and 3.8 +/- 1.1, respectively) or no drug (19.8 +/- 5.2, 12.8 +/- 1.8 and 2.6 +/- 0.7, respectively) (p less than 0.05, p less than 0.05 and p less than 0.05, respectively). The slope of the end-systolic pressure-volume relation 10 min after defibrillation and restoration of normal coronary perfusion pressure was depressed (percent of prefibrillation value) most by epinephrine infusion (72 +/- 17%, n = 6), less by no drug infusion (82 +/- 12%, n = 4) and was increased after phenylephrine infusion (143 +/- 17%, n = 6) (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

[Assessment of coronary bypass surgery by continuous ventricular function monitoring].

The sequential change of left ventricular function during exercise and recovery after exercise was assessed in 50 patients who had undergone coronary bypass surgery before and after the operation by means of continuous ventricular function monitoring system (VEST). Cardiac response was divided into 4 types with respect to the profiles of the left ventricular ejection fraction during exercise. Type A continued to increase; type B initially increased but decreased in severe exercise stages; type C did not change during exercise; type D continued to decrease. Most patients showed type C or D before surgery but showed type A after surgery. 9 patients with occluded grafts or ungrafted coronary arteries showed type B, C or D. Two patients with extended infarction and poor left ventricular function showed type C after surgery. In recovery period after exercise, the ejection fraction showed an overshoot. The mean ratio of peak ejection fraction during recovery to ejection fraction at rest increased from +62 +/- 12% before operation to +68 +/- 16% after operation (p less than 0.05). The recovery time after exercise was decreased from 195 sec before operation to 98 sec after operation (p less than 0.01). VEST revealed response of left ventricular function during exercise and recovery after exercise as far as detail abnormalities.

Adult↗

PubMed1988

Daily serial evaluation of left ventricular function with equilibrium radionuclide ventriculography following thrombolysis during acute myocardial infarction.

The changes in ventricular function after reperfusion by coronary thrombolysis are important when deciding about further definitive treatment necessary to ensure long-term vessel patency. The purpose of this study was to evaluate the early changes in left ventricular function after reperfusion. Left ventricular function was serially evaluated for 10 days in a group of 18 patients receiving intracoronary thrombolytic therapy for an acute myocardial infarction. Comparison of the global ventricular function in the successfully and unsuccessfully reperfused groups of patients showed significantly better function in the successful group than the unsuccessful group after the first day, which was maintained for the entire study period. Global and regional ventricular function in the successfully reperfused patients showed significant early improvement during the initial 72 h with maintenance of this improvement for the study period of 10 days. In the patients in whom reperfusion was unsuccessful, regional ventricular function showed no change, while the global function declined from day 5 to day 8 of the study period. This study then confirms the significant improvement in ventricular function after successful reperfusion. The time course pattern of the change in ventricular function indicates that the most significant improvement occurs within the first 72 h after reperfusion. These changes are similar to those previously reported in experimental animals.

Angioplasty, Balloon↗

PubMed1991

Relation between myocardial beta-adrenergic receptor and left ventricular function in patients with left ventricular volume overload due to chronic mitral regurgitation with or without aortic regurgitation.

The relation between myocardial beta-adrenergic receptor and left ventricular (LV) function was studied in 10 patients, aged 41 to 61 years (average 51), with LV volume overload mainly due to chronic mitral regurgitation. Beta-adrenergic receptors were examined using crude membrane in LV papillary muscle obtained at mitral valve replacement. Cardiac function was evaluated at preoperative cardiac catheterization with the interval to surgery of 1 to 33 months (average 7). Beta-adrenergic receptor density in 7 patients with New York Heart Association class II or III congestive heart failure was higher than that in 3 patients with class IV heart failure (59 +/- 19 vs 37 +/- 3 fmol/mg protein, p less than 0.05). Beta-adrenergic receptor density showed a positive correlation with end-systolic stress/end-systolic volume index ratio, the index for contractile function (p less than 0.005). Other parameters such as cardiac index, pulmonary artery wedge pressure and LV ejection fraction had no significant correlation to beta-adrenergic receptor. The results demonstrated that increases in symptom and LV dysfunction, particularly of the contractile state, was associated with decreased myocardial beta-adrenergic receptor density from possible down-regulation in patients with chronic mitral regurgitation with or without aortic regurgitation.

Adult↗

PubMed1979

Ventricular function and the native coronary circulation five years after myocardial revascularization.

Of 531 patients who underwent coronary artery bypass grafting during 1970 to 1973, 181 were restudied by ventriculography and by graft and coronary angiography at least 5 years following operation. Five patterns of postoperative ventricular function were identified: improved ventricular function resulting in normal left ventricular (LV) function; normal ventricular function that was unchanged; abnormal ventricular function that improved but did not reach normal; abnormal ventricular function that remained unchanged; and deterioration of LV function. Patients who regained (40) and those who retained normal ventricular function (49) comprise 49% of the series and patients with deterioration of ventricular function, only 20%. Graft patency and angina relief were significantly better in those with normal LV function than in those with LV deterioration. Progression of disease in grafted coronary arteries was similar in all groups, but was significantly higher in ungrafted coronary arteries (61.3%) in the patients showing deterioration than in either the improved patients or those with an unchanged normal LV (33.3% each) (p less than 0.05). The high incidence of progression of disease in ungrafted coronary arteries in the group with deterioration suggests that low graft patency and deterioration of ventricular function in this group might both be related to intrinsic acceleration of coronary atherosclerosis unrelated to operative intervention.

Angina Pectoris↗

PubMed1992

Mitral valve replacement in patients with severe mitral regurgitation and impaired left ventricular function.

We have studied short- and mid-term effects of preservation and excision of the mitral subvalvar support during mitral valve replacement in 40 patients, who had developed moderate to severe degree of left ventricular function impairment, secondary to pure severe mitral regurgitation. These patients had valve replacement, because valve anatomy was unsuitable for reconstructive procedures. Mitral subvalvar support was excised and valve replaced with a Björk-Shiley prosthesis, in 10 patients with moderately impaired left ventricular ejection fraction (mean 32% +/- 1.2%) and in 18 patients with severely impaired left ventricular function (left ventricular ejection fraction: 22% +/- 0.8%). In 12 patients with severely impaired left ventricular function (left ventricular ejection fraction: 20% +/- 1%) posterior subvalvar apparatus was preserved and valve replaced with a bioprosthesis. Prognosis of patients with moderately impaired left ventricular function was not influenced by the loss of chordopapillary support. Actuarial survival at 8 and 10 years was 46% +/- 7.8% for patients with severely impaired left ventricular function with chordopapillary support excised and 70% +/- 10% for patients with severely impaired left ventricular function with chordopapillary support preserved (p less than 0.01). Preservation of mitral subvalvar support is important in patients with severely impaired left ventricular function (left ventricular ejection fraction less than 25%).

Aged↗

PubMed1992

Exercise response assessed by continuous monitoring of ventricular function in patients with coronary bypass operations.

The response of left ventricular function during exercise and recovery after exercise was assessed in 35 patients with coronary artery bypass grafting before and after the operation by means of a continuous ventricular function monitor, which records serial beat-to-beat radionuclide data and calculates left ventricular ejection fractions every 20 seconds. The mean ejection fraction decreased with graded bicycle exercise from 48% +/- 9% to 41% +/- 11% (p less than 0.001) before operation but increased with exercise from 50% +/- 9% to 55% +/- 11% (p less than 0.001) after operation. Cardiac response was divided into four types with respect to the profiles of the ejection fractions during exercise. Type A continued to increase; type B initially increased but then decreased in late exercise stages; type C did not change significantly; type D continued to decrease. Most patients had type C or D responses before operation but type A after operation. Seven patients with occluded grafts or ungrafted coronary arteries had type B or D responses. Three patients with complete revascularization, including an internal thoracic artery and saphenous vein grafts, had type B responses. Three patients with extensive infarction and poor left ventricular function showed type C. In the early recovery period after exercise, most patients had an "overshoot" elevation of ejection fraction. The mean value increased from 59% +/- 10% before operation to 64% +/- 11% after operation (p less than 0.01). The recovery time after exercise was reduced from 2.8 minutes before operation to 1.8 minutes after operation (p less than 0.001). The continuous ventricular function monitor elucidated changes in left ventricular function both during exercise and recovery after exercise, as well as unmasking abnormalities in left ventricular function after coronary bypass operation.

Coronary Artery Bypass↗

PubMed1992

[Coronary artery bypass grafting in patients with poor left ventricular function using retrograde continuous cold blood cardioplegia].

Patients with poor left ventricular function or those requiring urgent surgery may have more extensive ischemic myocardial injury if myocardial preservation is incomplete. We have performed coronary artery bypass grafting (CABG) aimed at complete revascularization in such cases using RC-CBCP, which is considered more effective on myocardial preservation during aortic cross-clamping in particular to protect ischemic area distal to severe coronary artery stenosis or obstruction. In the present study, in 25 patients with poor left ventricular function (left ventricular ejection fraction; LVEF less than or equal to 0.3) including 10 patients who required urgent surgery, the operative results were evaluated. All the distal and proximal anastomoses of grafts (average 2.5 grafts) were completed during one aortic cross-clamping using RC-CBCP, therefore graft flow was obtained immediately after release of the aortic clamping. Though this method required 142 minutes of a mean aortic cross-clamping time, myocardial protection was considered to be preferable judging from postoperative isoenzymatic evaluation and improved ventricular function. Fifteen patients with elective CABG were all alive and restored to NYHA class I to II. Among 10 patients requiring urgent CABG, 4 patients with acute myocardial infarction died but others were restored to NYHA class I to II. We conclude that it is important to aim at complete coronary revascularization in patients with poor left ventricular function and RC-CBCP achieves more effective myocardial protection during CABG in the patients.

Adult↗

PubMed1989

Plasma concentrations of atrial natriuretic factor during positive end-expiratory pressure ventilation in dogs with normal or impaired left ventricular function.

The influence of positive end-expiratory pressure (PEEP) ventilation on plasma concentrations of atrial natriuretic factor (ANF) was studied in dogs anesthetized with sodium pentobarbital during normal cardiac function and during acutely impaired left ventricular function. Left ventricular impairment was induced by injecting repeated doses of polystyrene microspheres with a diameter of 50 microns into the main left coronary artery, causing a severe depression of left ventricular performance. This was accompanied by doubling of ANF concentrations measured in blood sampled from aorta. Application of PEEP (10 cmH2O (0.98 kPa] reduced plasma ANF in dogs both with normal and impaired left ventricular function. The decrease was significantly greater during left ventricular impairment compared to control, 31 and 19%, respectively. A positive correlation was observed between plasma ANF and transmural left ventricular end-diastolic pressure when all data were pooled, but not between ANF and transmural right atrial pressure. This implies that transmural left ventricular end-diastolic and hence transmural left atrial pressure probably is the principal determinant of acute ANF release in this model. Reduced plasma ANF in response to PEEP even during acute left ventricular impairment when ANF release was augmented, was probably due to diminished atrial distension during PEEP ventilation.

Animals↗

PubMed1990

Pharmacodynamic effect of nicardipine on left ventricular function in systemic sclerosis.

Left ventricular dysfunction in systemic sclerosis may be due in part to myocardial ischemia caused by a disturbance in coronary microcirculation. We evaluated the pharmacodynamic effect of the calcium channel blocker nicardipine on left ventricular function assessed by radionuclide ventriculography in 20 patients with systemic sclerosis. Resting gated, blood-pool images were obtained at baseline and 90 min after 40 mg of oral nicardipine. The mean (+/- SEM) left ventricular ejection fraction significantly increased from 65.4 +/- 2.3% at baseline to 71.3 +/- 2.3% after nicardipine (p less than 0.005). The mean global defect score significantly decreased from 2.90 +/- 0.73 without nicardipine to 1.50 +/- 0.52 with nicardipine (p less than 0.01). The mean number of left ventricular sectors with severe hypokinesis significantly decreased from 0.80 +/- 0.24 at baseline to 0.20 +/- 0.09 after nicardipine (p less than 0.05). No significant side effects were observed with nicardipine. These results demonstrate short-term improvement in left ventricular function with nicardipine in patients with systemic sclerosis.

Adult↗