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PubMed1993

Effect of disrupting the mitral apparatus on left ventricular function in dogs.

BACKGROUND: The importance of the mitral apparatus to left ventricular function has been suggested in clinical studies. The effect of disruption of the mitral apparatus on left ventricular diastolic and systolic properties has not been fully documented. METHODS AND RESULTS: We investigated the end-diastolic and end-systolic pressure-volume and stroke work-end-diastolic volume relations and measured the isovolumic relaxation time constant (tau infinity) during nonfilling beats before and after disruption of the mitral apparatus under different loading conditions in 14 dogs using our recently developed volume-clamping technique for the in situ left ventricle. Disruption of the mitral apparatus increased left ventricular diastolic equilibrium volume (V0d) without changing the slope of the end-diastolic pressure-volume relation (Sd) and increased end-systolic pressure-volume relation dead volume (V0s) and volume-axis intercept of stroke work-end-diastolic volume relation (V0sw) without changing the slopes of these relations (maximum elastance, Ees, and Ssw). Disruption of the mitral apparatus increased tau infinity. CONCLUSION: Disruption of the mitral apparatus increases the equilibrium volume without changing left ventricular diastolic stiffness or contractility and slows left ventricular relaxation. These results support and help explain the clinical observation that it is desirable to maintain the mitral apparatus during mitral valve replacement surgery.

Animals↗
PubMed2002

Non-imaging nuclear monitoring of left ventricular function: twenty-five years of technical development and clinical experience.

Although the first non-imaging nuclear probe for clinical application was already available 25 years ago, this technique is still underused for the assessment of ventricular function. Over the years substantial technological progress rendered nuclear probes more accurate and easier to use, and so far the applicability of these devices has been evaluated in several experimental and clinical contexts. Bedside devices can be used in the evaluation of hemodynamically unstable patients and of drug therapy. In patients with several heart diseases, particularly with ischemic cardiomyopathy, accurate information on the changes in ventricular function occurring during routine activities, as well as during structured activities, can be provided using the ambulatory probes. This review will focus on the development and clinical application of these diagnostic tools.

Cardiovascular Agents↗
PubMed1989

Acute changes in global and regional rest left ventricular function after successful coronary angioplasty: comparative results in stable and unstable angina.

The immediate effects of successful percutaneous transluminal coronary angioplasty on global and regional left ventricular function were assessed by comparing 30 degrees right anterior oblique left ventricular angiograms performed immediately before and after angioplasty on 39 patients undergoing 42 successful procedures. Mean (+/- SD) lesion stenosis decreased from 88 +/- 10% to 35 +/- 11% (p less than or equal to 0.001), whereas left ventricular ejection fraction increased from 57 +/- 11% to 64 +/- 10% (p less than or equal to 0.001) for the entire group. Left ventricular functional changes were further subgrouped according to stability of angina. Eighteen procedures were performed on 17 patients with stable angina: 24 procedures were performed on 22 patients with unstable angina defined as angina at rest or on minimal activity or recently accelerated angina. There were no significant subgroup differences in mean age, gender ratio, vessel anatomy, drug therapy or extent of coronary stenosis before or after angioplasty. Global ejection fraction increased significantly for the unstable group (from 54 +/- 11% to 66 +/- 9%, p less than or equal to 0.001) but was unchanged for the stable group (from 61 +/- 9% to 61 +/- 11%, p = NS). In unstable angina, regional ejection fraction (segmental area method) increased for both jeopardized (from 37 +/- 11% to 52 +/- 9%, p less than or equal to 0.001) and nonjeopardized myocardial segments (from 43 +/- 13% to 51 +/- 13%, p less than or equal to 0.001), but improvement was significantly (p less than or equal to 0.02) greater in jeopardized segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Relation of regional echo amplitude to left ventricular function and the electrocardiogram in left ventricular hypertrophy.

In order to determine the relation between three manifestations of left ventricular hypertrophy--ST-T wave changes on the electrocardiogram, diastolic disturbances, and increased myocardial echo intensity--M mode and cross sectional echocardiograms were recorded in 12 normal subjects, 15 athletes, 16 patients with hypertrophic cardiomyopathy, and 42 patients with secondary left ventricular hypertrophy due to aortic stenosis (20), severe essential hypertension (8), coarctation (7), or subaortic stenosis (7). M mode echocardiograms were digitised and cross sectional echocardiograms were analysed for regional echo intensity. In patients with hypertrophy regional echo amplitude was significantly increased in mid and basal septum and posterior left ventricular wall. Patients with increased echo amplitude in any region showed a higher incidence of ST-T wave abnormalities than those without and of diastolic abnormalities--including prolongation of isovolumic relaxation time, delay in mitral valve opening with respect to minimum cavity dimension, and a reduction in peak rate of posterior wall thinning and dimension increase. There was a significant rank order correlation between median pixel count and these diastolic abnormalities. No significant differences were demonstrable in these relations between the diagnostic groups. By contrast, electrocardiographic findings, diastolic function, and pixel count were uniformly normal in athletes, although the increase in left ventricular mass was similar to that in the patients. Thus an increase in left ventricular mass alone is not responsible for repolarisation or wall motion abnormalities occurring in pathological left ventricular hypertrophy. These latter changes are, however, strongly associated with the change in myocardial properties detected as an increase in echo intensity and may be due to increased interstitial fibrosis.

Adult↗
PubMed1989

Effects of uncomplicated coronary artery bypass graft surgery on global and regional left ventricular function at rest. Study by equilibrium radionuclide angiocardiography.

To evaluate the effects of uncomplicated revascularization surgery on resting global and regional left ventricular function we studied 34 patients, enrolled consecutively, by radionuclide angiocardiography. After surgery, we found no significant change in global left ventricular ejection fraction; this was true even in the subgroup of 14 patients who developed paradoxical septal motion. This finding indicates that the development of paradoxical septal motion after uncomplicated cardiac surgery does not compromise global left ventricular function. Both in the subgroup of patients with paradoxical septal motion and in the subgroup without paradoxical septal motion regional ejection fraction calculations showed the same postoperative pattern consisting of increase of the proximal and distal posterolateral regional ejection fraction, increase in the inferoapical regional ejection fraction and unchanged proximal and distal septal regional ejection fraction. In our patients paradoxical septal motion is not due to pericardial effusion, conduction disturbance, septal ischemia or infarction. Our data suggest that the anteromedial translation of the entire heart during systole, due to surgical removal of constraints, may account for both the false improvement of posterolateral and inferoapical regional wall motion and the development of paradoxical septal motion.

Adult↗
PubMed1974

Effects of DC electric countershock on ventricular function, cation balance and endogenous norepinephrine in the dog heart.

Effects of DC electric countershock on cardiac function in thoracotomized dogs were evaluated from recordings of ECG, aortic pressure, left ventircular pressure and its first derivative, and coronary sinus flow. Samples of arterial and coronary venous plasma and left ventricular myocardium obtained before and after countershock at times corresponding to post-shock arrhythmias and recovery were analyzed for Mg++, K+ and Ca++, and norepinephrine. At 1 min after countershock, ECG changes included transient cardiac arrhythmias and ST segment alterations, accompanied by depressed ventricular function and decreased myocardial Ca++ concentration. At 5 min postshock, coronary venous Mg++ and K+ concentrations had risen and ventricular function was still depressed. Function recovered within 10-20 min. There was no evidence of consistent loss of endogenous myocardial norepinephrine.

Animals↗
PubMed2003

Effects of isolated obesity on systolic and diastolic left ventricular function.

BACKGROUND: Obesity is associated with increased cardiovascular morbidity and mortality. A direct effect of isolated obesity on cardiac function is not well established. OBJECTIVE: To determine the direct effect of different grades of isolated obesity on echocardiographic indices of systolic and diastolic left ventricular function. METHODS: 48 obese and 25 normal weight women were studied. They had no other pathological conditions. Obesity was classed as slight (n = 17; body mass index (BMI) 25-29.9 kg/m2), moderate (n = 20; BMI 30-34.9 kg/m2), or severe (n = 11; BMI > or = 35 kg/m2). Echocardiographic indices of systolic and diastolic function were obtained, and dysfunction was assumed when at least two values differed by > or = 2 SD from the normal weight group. RESULTS: Ejection fraction (p < 0.05), fractional shortening (p < 0.05), and mean velocity of circumferential shortening (p < 0.05) were increased in slight and moderate obesity. Left ventricular dimensions were increased (p < 0.001) but relative wall thickness was unchanged. No obese patients met criteria for systolic dysfunction. In obese subjects, the mitral valve pressure half time (p < 0.01) and the left atrial diameter (p < 0.001) were increased and the deceleration slope was decreased (p < 0.01); all other diastolic variables were unchanged. No differences were found between obesity subgroups. Subclinical diastolic dysfunction was more prevalent among obese subjects (p = 0.002), being present in two with slight obesity (12%), seven with moderate obesity (35%), and five with severe obesity (45%). BMI correlated significantly with indices of left ventricular function. CONCLUSIONS: Subclinical left ventricular diastolic dysfunction is present in all grades of isolated obesity, correlates with BMI, and is associated with increased systolic function in the early stages of obesity.

Adolescent↗
PubMed1977

Protective effect of methylprednisolone on ischaemic myocardium assessed by ventricular function.

Intracardiac surgical procedures are best carried out when the heart is still and bloodless. This condition, however, produces myocardial cellular damage with loss of contractility and compliance unless some protection can be provided. Myocardial contractility and compliance is best studied by isovolumic ventricular function tests, which were used to evaluate the protective effect of methylprednisolone on the isolated cross-perfused canine heart made ischaemic for 2 hours. Control experiments included 2 hours of ischaemia without methylprednisolone, and 2 hours of continuous normothermic cross-perfusion. The methylprednisolone-treated hearts had probably significantly better ventricular function after 2 hours of ischaemia than did hearts without the methylprednisolone, while the cross-perfused hearts were best overall. This work suggests that methylprednisolone may have a protective effect on the ischaemic myocardium of the intact canine heart.

Animals↗
PubMed1982

The influence of hemodialysis fistulas on circulatory dynamics and left ventricular function.

This study was designed to examine the influence of arteriovenous (A-V) fistulas on cardiac output and left ventricular performance in 13 uremic patients on regular hemodialysis. M-mode echocardiography and systolic time intervals were used to derive indices of left ventricular function, and cardiac output was measured by thermodilution. Measurements were performed before and after acute digital occlusion of the A-V fistulas. Occlusion of a single fistula caused systemic vascular resistance and the systolic diameter of the left ventricle to increase from 9.6 +/- 1 to 13.5 +/- 2 units (p less than 0.001) and from 3.2 +/- .3 to 3.4 +/- .4 (p less than 0.05) respectively. The increase in afterload caused a reduction in cardiac output from 11.0 +/- 1 to 9.6 +/- 1 l/min (p less than 0.001) and probably accounted for the minor, though not significant, "deterioration" in the indices of left ventricular function. Bilateral fistula occlusion in 8 patients exaggerated these changes, and the reduction in fractional shortening from 43 +/- 4 to 37 +/- 4% was significant at the 5% level. In two patients with severe left ventricular failure, fistula occlusion caused a more pronounced deterioration in cardiac performance. These results show that acute A-V fistula occlusion effectively lowers cardiac output and is, therefore, likely to be beneficial in the management of high output failure. However, when intrinsic left ventricular disease is the primary etiological factor in heart failure, fistula occlusion is unlikely to be helpful, and may worsen the hemodynamic derangement.

Adult↗
PubMed2000

Differential effects of right versus left stellate ganglion block on left ventricular function in humans: an echocardiographic analysis.

STUDY OBJECTIVES: To evaluate the effects of unilateral stellate ganglion blockade on left ventricular function. DESIGN: Prospective cohort of patients with chronic regional pain syndrome type I and II of the upper extremity requiring therapeutic stellate ganglion blockade. SETTING: University-affiliated hospital. PATIENTS: Fifteen adult ASA physical status I and II patients with the diagnosis of chronic regional pain syndrome type I and II of the arm were studied. Right stellate ganglion block was performed in nine subjects and a left in six. INTERVENTIONS: Stellate ganglion block was performed with 10 mL of 1% plain Xylocaine. Transthoracic echocardiograms were performed immediately prior and 30 min following the block. MEASUREMENTS: Heart rate and blood pressure were monitored at regular intervals. Global systolic function was determined by calculating ejection fraction. Regional systolic motion was evaluated on the short axis and four-chamber views using the American Society of Echocardiography criteria. Diastolic function was assessed with pulsed-wave Doppler of the left ventricular outflow tract and the mitral valve. Data collected included isovolumic relaxation time and early and atrial velocity patterns. MAIN RESULTS: A successful stellate ganglion block was achieved in all patients. Blood pressure and heart rate were not significantly different during data collection. Patients who underwent a right stellate ganglion block showed no significant differences in systolic or diastolic function. Following a left stellate ganglion block, global and regional systolic function remained unchanged. Isovolumic relaxation time was increased but did not reach statistical significance (80 +/- 13 ms to 88 +/- 9 ms; p = 0.09). Left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV) were significantly increased (LVEDV from 73 +/- 9 mL to 100 +/- 9 mL, p < 0.02; LVESV from 31 +/- 4 mL to 37 +/- 4 mL, p < 0.03). CONCLUSIONS: In patients without cardiovascular disease, unilateral denervation of the left ventricle after stellate ganglion block produces no clinical deleterious effects on left ventricular function.

Adult↗
PubMed2005

Impact and determinants of left ventricular function in patients undergoing primary percutaneous coronary intervention in acute myocardial infarction.

We evaluated the prognostic effect of baseline left ventricular function and the determinants of its recovery after acute myocardial infarction (AMI) treated by primary angioplasty. Left ventriculography was performed during the index procedure in 1,620 of 2,082 patients (78%) who underwent primary angioplasty for AMI in the CADILLAC trial. One-year survival rate was significantly lower in patients whose baseline left ventricular ejection fraction (LVEF) was <40% than in those whose LVEF was > or =40% (89.0% vs 97.2%, respectively, p <0.0001). The effect of baseline left ventricular dysfunction on mortality was confined to the first 3 months after AMI; thereafter, survival was independent of baseline LVEF. By multivariate analysis, baseline LVEF (hazard ratio 0.93, 95% confidence interval 0.90 to 0.97, p <0.001) and infarct zone regional wall motion (hazard ratio 2.67, 95% confidence interval 1.08 to 6.63, p = 0.03) were independent predictors of 1-year mortality. Seven-month convalescent LVEF was also directly related to baseline LVEF and inversely correlated with previous AMI, multivessel coronary disease, preprocedural Thrombolysis In Myocardial Infarction grade 0 to 2 flow, larger infarct artery diameter, and infarct artery restenosis at follow-up. In conclusion, baseline left ventricular function measured during the index procedure is a strong independent predictor of early and late survival after primary angioplasty. Simple clinical and angiographic features readily available at the time of primary angioplasty also predict convalescent LVEF and are thus of prognostic utility.

Aged↗
PubMed1996

Left ventricular function during exercise in athletes and in sedentary men.

Aim of this study was to evaluate left ventricular function during exercise in 10 male elite runners and in 10 sedentary males. End-diastolic (EDV) and end-systolic volume (ESV), left ventricular ejection fraction (EF), early peak transmitral flow velocity (peak E), time-velocity integral of mitral inflow (m-TVI); mitral cross sectional area (m-CSA); mitral stroke volume (SV), and cardiac output (CO) were measured by echo-Doppler. We simultaneously analyzed: VO2max by spirometric method, mean arterial blood pressure (MAP) by sphygmomanometer, and heart rate (HR) by ECG. The parameters were measured under basal conditions (level 1), at 50% of maximal aerobic capacity (level 2), at peak of exercise (level 3) and during recovery. Ejection fraction in athletes increased significantly at peak of exercise through Frank-Starling mechanism. Stroke volume and cardiac output increased significantly in athletes at peak of exercise. Left ventricular diastolic function was superior in athletes versus controls: in fact, higher peak E in athletes enhanced early diastolic ventricular filling. Therefore, the athletes showed complex cardiovascular adjustments induced by training, which allowed an higher peak working power, a greater cardiac output, and VO2max when compared with an untrained control population.

Adult↗
PubMed1992

Lack of myocardial perfusion immediately after successful thrombolysis. A predictor of poor recovery of left ventricular function in anterior myocardial infarction.

BACKGROUND: We investigated myocardial perfusion dynamics after thrombolysis and its clinical implications. METHODS AND RESULTS: We studied 39 patients with acute anterior myocardial infarction (AMI). Myocardial contrast echocardiography (MCE) was performed before and immediately after successful reflow with intracoronary injection of sonicated Ioxaglate. The average segmental score by two-dimensional echocardiography (graded 0, normal, to 3, akinetic/dyskinetic) and global ejection fraction (left ventricular ejection fraction, LVEF%) by left ventriculography were measured at 1 day and at 4 weeks after reflow. Hypokinesis in the infarct region was assessed by the centerline method and expressed in terms of standard deviations (regional wall motion [RWM]: SD/chord) of normal. Immediately after reflow, 30 of 39 patients (group A) showed significant contrast enhancement within the risk area. The other nine patients (23%, group B), however, showed the residual contrast defect in the risk area (myocardial no reflow). There were no significant differences in the elapsed time, angiographic collateral grade, and degree of residual stenosis between group A and group B. Before reflow, both groups exhibited similar levels of global and regional left ventricular function. Improvement in global (LVEF, average segmental score) and regional left ventricular function was greater in group A than in group B (average segmental score, 0.44 +/- 0.41 versus 0.97 +/- 0.36, p less than 0.01; LVEF, 56.4 +/- 13.4 versus 42.7 +/- 8.9, p less than 0.05; RWM, -1.87 +/- 0.85 versus -3.18 +/- 0.52, p less than 0.005). CONCLUSIONS: MCE demonstrates that angiographically successful reflow cannot be used as an indicator of successful myocardial reperfusion in AMI patients. The residual contrast defect in the risk area demonstrated immediately after reflow is a predictor of poor functional recovery of the postischemic myocardium.

Coronary Circulation↗
PubMed1995

Improvement of global and regional left ventricular function by percutaneous transluminal coronary angioplasty after myocardial infarction.

OBJECTIVES: This study was designed to evaluate how elective percutaneous transluminal coronary angioplasty of the infarct-related vessel after acute myocardial infarction affects global ejection fraction and regional wall function. BACKGROUND: The severity of the residual stenosis of the infarct-related artery after thrombolysis is an important predictor of changes in left ventricular function; however, the optimal time to restore complete perfusion in the infarct area has not been determined. METHODS: We prospectively evaluated patients with a first myocardial infarction, postinfarction ischemia and residual high grade stenosis with reduced flow in the infarct-related artery who underwent successful coronary angioplasty. The group comprised 74 patients (61 men, 13 women with a mean age +/- SD of 55.9 +/- 9.9 years). Global ejection fraction and infarct region function (expressed as area ejection fraction) were angiographically measured before coronary angioplasty (3.9 +/- 2.1 weeks after infarction) and on routine follow-up study 6 +/- 1 months after angioplasty. RESULTS: Restenosis with reduced flow occurred in 15 patients (20%). The global ejection fraction in patients with complete flow at follow-up increased significantly from 56.8% +/- 12% to 62.3% +/- 12.5% (p < 0.001). Regional wall motion of the infarct area increased from 12.1% to 22.5% (p = 0.001) in patients with anterior wall infarction and from 20.4% to 28.5% (p = 0.002) in those with inferior wall infarction. In patients with restenosis there was no difference at follow-up either in global ejection fraction (from 47.7% +/- 7.7% to 47.1% +/- 12.7%, p = 0.57) or in regional wall motion of the infarct area. CONCLUSIONS: Global and regional myocardial dysfunction due to postinfarction ischemia lessens significantly after successful coronary angioplasty of the infarct-related coronary artery with long-term sustained normal, complete flow. In contrast, restenosis with reduced flow prevents long-term improvement of left ventricular function.

Aged↗
PubMed1993

Effect on verapamil on ventricular function: studies in denervated human heart.

Verapamil has complex influences on ventricular function owing to its direct myocardial effects, vasodilation, and reflex activation of the sympathetic nervous system. To investigate the direct myocardial effects of verapamil in humans independent of reflex sympathetic stimulation, we administered the drug to 13 recent heart transplant recipients with denervated ventricles. Hemodynamics and radionuclide angiograms were recorded at baseline, with altered loading conditions, and after intravenous (i.v.) verapamil (median dose 4 mg). Left ventricular (LV) systolic and diastolic function was analyzed by systolic pressure-volume relations (SPVR) and peak filling rate (PFR), respectively. Verapamil caused a decrease in blood pressure (BP) and heart rate (HR) with increases in right atrial pressure (RAP 6 +/- 3-8 +/- 3, p < 0.01) and pulmonary artery wedge pressure (PAWP, 9 +/- 3-11 +/- 3 mm Hg, p < 0.01) pressures. LV ejection fraction (EF) decreased (69 +/- 7-66 +/- 8%, p < 0.02) in association with an increase in LV end-systolic counts (3.45 +/- 1.27 to 4.72 +/- 1.78 kcts, p < 0.001). In 11 of 13 patients, the SPV point after verapamil administration was decreased from the line established during altered loading conditions. PFR (4.05 +/- 0.81 to 4.11 +/- 0.76 EDV/s) was unchanged. In the denervated ventricle, verapamil has negative chronotropic and inotropic effects with minimal effects on PFR.

Adult↗
PubMed1982

Survival of coronary artery disease patients with stable pain and normal left ventricular function treated medically or surgically at Duke University.

We evaluated the survival rates of medically and surgically treated patients with one-, two- or three-vessel coronary disease (CAD), stable pain, and normal left ventricular function observed at the Duke University Medical Center over an 11-year period. There was no statistical difference in survival when medical and surgical treatment were compared in patients with one-, two- or three-vessel disease (greater than or equal to 75% vessel occlusion). However, the survival curve of patients with three-vessel disease treated surgically consistently exceeded that of those treated medically over a 7-year follow-up period. This difference was not statistically significant, but suggests the need for further study in this group. When patients with 50% or greater lesions in three vessels, stable angina and normal left ventricular function were evaluated, surgical survival was greater than medical survival, although the difference is not statistically significant. The survival in the Duke medical group is substantially higher than that reported for medical patients in the European Cooperative Trial, which suggests that the significant differences surgical in survival in the European Cooperative Trial were largely due to a lower medical survival than that in the Duke medical group.

Coronary Artery Bypass↗
PubMed2002

Assessment of ventricular function with single breath-hold real-time steady-state free precession cine MR imaging.

OBJECTIVE: The aim of our study was to evaluate whether a recently developed real-time steady-state free precession (trueFISP) cine sequence could be used to assess left ventricular function in a single breath-hold. CONCLUSION: Using real-time trueFISP permits one to assess left ventricular function in a single breath-hold. The dramatic reduction in data acquisition time does require some compromises. The temporal and spatial resolutions of images obtained with real-time trueFISP were considerably lower than those achieved with segmented trueFISP. Further reduction of the TR or the use of sensitivity encoding could improve temporal resolution and eliminate other limitations of real-time trueFISP.

Adult↗
PubMedDate not supplied

Assessment of the heart by histochemical and birefringence techniques as compared with ventricular function tests.

We have compared results of isovolumic ventricular function studies and results of histochemical and birefringence examinations of biopsy specimens from 80 isolated canine hearts both before and after three hours of preservation utilizing several variables. The direct and derived mechanical tests and histochemical and birefringence assessments of the myocardium were correlated by multiple regression analysis. Our results suggest that initial ventricular health may be indicated by acid hematein staining of free phospholipids and by the response of myocardial birefringence to adenosine triphosphate and calcium, while succinic dehydrogenase staining and birefringence without adenosine-triphosphate treatment are more useful in showing ventricular deterioration during operation.

Animals↗