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Influence of resting left ventricular function on the left ventricular response to exercise in patients with coronary artery disease.

First-pass radionuclide angiocardiography was used to access the left ventricular response to submaximal exercise in 150 patients with coronary artery disease (CAD). To test the hypothesis that resting systolic left ventricular function as determined by left ventricular ejection fraction (LVEF) was a predictor of the hemodynamic response to exercise, the study group included patients with a wide range of resting LVEF (0.12-0.82). The influences of resting LVEF, resting end-diastolic volume, the number of diseased vessels, exercise end point and exercise double product on the change in LVEF (delta LVEF) during exercise were tested using multiple linear regression analyses. Resting LVEF was a highly significant predictor of the delta LVEF (p = 0.0001). Exercise duration was not related to either the resting LVEF or the delta LVEF. For the 112 patients in whom coronary anatomy was known, resting LVEF retained its significance as a predictor of delta LVEF (p = 0.002) even after adjustment for the significance of the extent of CAD (p = 0.0007) and the exercise end point (p = 0.06). Patients with normal resting LVEF showed the most profound decreases in LVEF, the highest frequency of new regional dysfunction and the largest relative increase in end-diastolic volume during exercise. As rest LVEF decreased, the magnitude of the delta LVEF and the frequency of new regional dysfunction decreased. Therefore, left ventricular function at rest is an important determinant of the direction and magnitude of change in left ventricular function during exercise.

Adult↗

Electrophysiologic testing in patients at high risk for sudden cardiac death. I. Nonsustained ventricular tachycardia and abnormal ventricular function.

Nonsustained ventricular tachycardia, although usually asymptomatic, is associated with a high risk of sudden cardiac death in patients with depressed left ventricular function. To test the vulnerability of such patients to symptomatic and potentially life-threatening arrhythmias, complete electrophysiologic studies were performed in 58 patients with clinically documented nonsustained ventricular tachycardia (greater than or equal to three complexes but less than 15 seconds of self-terminating ventricular tachycardia by 24 hour ambulatory electrocardiographic [Holter] or telemetric monitoring) and abnormal left ventricular function (ejection fraction less than 50% by radionuclide angiography). All patients had nonsustained ventricular tachycardia in the absence of antiarrhythmic drugs, acute ischemia, long QT syndrome, recent infarction or electrolyte abnormalities. The stimulation protocol for each patient included the introduction of single, double and triple ventricular extrastimuli at three cycle lengths (sinus, 600 and 450 ms) and two right ventricular sites (apex and outflow tract). A sustained ventricular tachyarrhythmia was induced in 23 patients (40%) and a nonsustained ventricular tachycardia in 14 patients (24%). Induction of sustained tachycardia correlated with the presence of akinesia or aneurysm, or both, by radionuclide angiography, but not with ejection fraction or presence or absence of coronary artery disease. These results indicate that: 1) patients with clinical nonsustained ventricular tachycardia and chronic left ventricular dysfunction have a high incidence of inducible sustained ventricular tachycardia or ventricular fibrillation; and 2) electrophysiologic testing may allow further substratification of risk of sudden cardiac death in high risk patients with nonsustained ventricular tachycardia.

Adult↗

Left ventricular functional reserve in nonobstructive hypertrophic cardiomyopathy: evaluation by continuous left ventricular function monitoring.

UNLABELLED: The cardiac functional response to exercise in patients with nonobstructive hypertrophic cardiomyopathy (HCM) was evaluated using a continuous ventricular function monitor with a cadmium telluride detector (CdTe-VEST). METHODS: Supine ergometric exercise was performed under CdTe-VEST monitoring in 41 patients with nonobstructive HCM (34 men and 7 women, age 18-72 yr, mean 51 yr) and 15 patients without cardiac disease (9 men and 6 women, age 36-56 yr, mean 49 yr). RESULTS: Although 20 of 41 patients with HCM maintained a LVEF above baseline at peak exercise (Group A), 21 did not show an EF increase at peak exercise (Group B). Exercise duration and work load in Group A were longer and higher, respectively, than in Group B. Resting EF in Group B (72 +/- 7.7%) was significantly higher than that in Group A (65 +/- 8.2%) and the control group (62 +/- 5.9%). The EF increase from baseline to EF overshoot during recovery and the time to EF overshoot were lower and longer, respectively, in Group B than in Group A and the control group. Septal wall thickness and the septum-to-posterior-wall-thickness ratio between Groups A and B were not different. ST-segment depression was observed in all 21 Group B patients and in 8 of the Group A patients. CONCLUSION: In patients with nonobstructive HCM, left ventricular dysfunction during exercise and during recovery was frequently observed but was not related to the degree of septal wall hypertrophy. The CdTe-VEST is a useful means to evaluate left ventricular functional reserve to exercise in patients with HCM.

Adolescent↗

[Surgical results in mitral insufficiency: prognostic value of the indices of left ventricular function].

Left ventricular function is a major prognostic factor in patients with mitral regurgitation, but the ability of echocardiographic and hemodynamic parameters to predict the surgical result is controversial. We investigated the prognostic role of various pre-operative indices of left ventricular function in 23 consecutive patients who underwent successful surgical correction of chronic mitral regurgitation. At a mean follow-up of 20 +/- 16 months, patients underwent echocardiography and radio-nuclide angiography and were grouped according to the post-operative left ventricular ejection fraction. Group A was made up of 16 patients with a left ventricular ejection fraction greater than or equal to .45: they showed post-operative reduction of the left ventricular end-diastolic diameter (from 36.3 +/- 3.2 to 30.5 +/- 4.5 mm/m2; p less than .001) and of the radius/thickness ratio (from 3.5 +/- 0.6 to 2.9 +/- 0.6; p less than .01). In 7 patients (group B), post-operative left ventricular ejection fraction was less than .45 and no significant changes in the left ventricular end-diastolic diameter (from 41.5 +/- 2.7 to 36.9 +/- 6.1 mm/m2; NS) or the radius/thickness ratio (from 3.9 +/- 0.9 to 3.4 +/- 1.0; NS) were observed. During the follow-up all group A patients remained asymptomatic or minimally symptomatic, whereas 2 group B patients died of refractory left ventricular failure. Pre-operative left ventricular volumes and diameters, both at end-diastole and end-systole, were significantly greater in group B patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Effects of left heart bypass on right ventricular function.

Right ventricular function has been studied in a canine ejecting heart model in-situ with intact sympathetic innervation and constant cardiac output, during varying degrees of left heart bypass ratio ranging from nil to total left ventricular decompression. The right ventricular function deteriorates as the left heart bypass ratio increases, reaching the maximal degree of RV depression when the LV is maximally decompressed. Some practical implications for the conduction of left heart bypass are discussed.

Animals↗

Comparison of cardiac sympathetic nervous function with left ventricular function and perfusion in cardiomyopathies by (123)I-MIBG SPECT and (99m)Tc-tetrofosmin electrocardiographically gated SPECT.

UNLABELLED: The objective of this study was to clarify the relationship between cardiac sympathetic nervous function (CSNF) and left ventricular (LV) function and perfusion in hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). METHODS: Thirty-eight cases (32 males, 6 females; mean age, 56 +/- 15 y), consisting of 5 healthy control subjects, 15 patients with DCM, and 18 patients with HCM, were studied with (123)I-metaiodobenzylguanidine (MIBG) and (99m)Tc-tetrofosmin SPECT. CSNF was evaluated from cardiac uptake and washout of MIBG, whereas LV perfusion and function were evaluated from tetrofosmin uptake and wall thickening on electrocardiographically gated SPECT. As quantitative parameters of global cardiac MIBG uptake and washout, the heart-to-mediastinum ratio (H/M) and percentage washout were calculated from early and delayed planar images. As quantitative regional parameters, the regional uptake and percentage washout of MIBG were calculated from SPECT images dividing the left ventricle into 12 segments. In the tetrofosmin study, the H/M and LV ejection fraction were calculated as the parameters of global LV perfusion and function. As quantitative regional parameters, the regional uptake and wall thickening were also calculated for the 12 myocardial segments using the quantitative gated SPECT software. Multiple linear regression analysis was performed to investigate the correlations between the parameters from the 2 studies. RESULTS: In DCM and HCM, multiple linear regression analysis of the regional parameters showed significant correlations between LV function and CSNF (P < 0.0001) and between LV perfusion and CSNF (P < 0.0001). According to the partial correlation coefficients, washout and early uptake of MIBG were the most significant factors for predicting LV function and LV perfusion, respectively. CONCLUSION: In cardiomyopathies, CSNF was closely related to LV function. The quantitative parameters of MIBG washout could reflect cardiac functional impairment. Early MIBG uptake might be determined by myocardial perfusion in cardiomyopathies.

3-Iodobenzylguanidine↗

Importance of left ventricular function and systolic ventricular interaction to right ventricular performance during acute right heart ischemia.

To determine whether modulation of systolic ventricular interaction influences right ventricular performance during right heart ischemia, the effects of septal ischemia and inotropic stimulation were studied in 15 dogs in an open chest preparation. Right coronary branch occlusions led to right ventricular dilation and free wall dyskinesia, reversed septal curvature and reduced left ventricular diastolic volume. In systole, the septum thickened but bulged paradoxically into the right ventricle generating an active but depressed right ventricular systolic pressure (28.9 +/- 5.5 to 22.1 +/- 4.5 mm Hg), with associated decreases in right ventricular stroke work (5.66 +/- 0.94 to 1.92 +/- 0.53 g.m/m2) and left ventricular systolic pressure (123 +/- 11 to 80 +/- 10 mm Hg). Septal ischemia induced systolic septal thinning, left ventricular dilation and decreased left ventricular systolic pressure (80 +/- 10 to 55 +/- 10 mm Hg) and stroke work. Although the extent of paradoxic septal displacement increased, there were further decrements in right ventricular systolic pressure (22.1 +/- 4.5 to 18.7 +/- 4.3 mm Hg) and stroke work (1.92 +/- 0.53 to 0.7 +/- 0.2 g.m/m2). Dopamine infusion augmented left ventricular free wall contraction and increased left ventricular systolic pressure (55 +/- 10 to 172 +/- 17 mm Hg) and stroke work. Although systolic septal thinning persisted, the extent of paradoxic septal displacement increased strikingly and, despite continued right ventricular free wall dyskinesia, right ventricular systolic pressure increased (18.7 +/- 4.3 to 39.6 +/- 6.2 mm Hg) as did right ventricular stroke work (0.7 +/- 0.2 to 7 +/- 1.6 g.m/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Effects of nicorandil on regional perfusion and left ventricular function.

Left ventricular function and regional perfusion were evaluated by two study designs in patient groups with stable ischemic coronary artery disease (CAD): (1) using conventional left ventricular angiographies and (2) applying myocardial contrast echocardiography. The aim of the studies was to establish the effects of sublingually or orally applied nicorandil (N) on pacing-induced myocardial ischemia (MIS). In the first angiographic study, in nine patients with ischemic CAD and with pacing-inducible MIS, the effect of N, 20 mg sublingually, on hemodynamics and regional wall motion (RWM) were studied. There were no parameter changes without MIS being induced when comparing measurements at the 7th and 14th minute after N application to control values (p > 0.05). In the 15th and 16th minutes after N, pacing-induced MIS could no longer be elicited but left ventricular pump function improved; comparing MIS with N versus MIS without N: ejection fraction improved by 21%, cardiac index by 37%, and RWM by 21%, while filling pressure fell by 41% and systemic vascular resistance fell by 29%. Thus, N-mediated "protection from ischemia" with rather improved hemodynamics and RWM corresponds with alterations that theoretically could have been expected after nitroglycerin given under the above conditions. In the second echocardiographic study, regional perfusion was assessed in 10 patients by intracoronary injection of a newly developed echo contrast medium (ECM) and measurement of ECM washout halftime (t1/2) over opacified myocardial regions of interest, which displayed wall motion abnormalities already at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Left ventricular function during stable sustained ventricular tachycardia. Hemodynamic and echo-Doppler analysis.

To assess the left ventricular function during sustained stable ventricular tachycardia (VT), ten patients, aged 58 to 74, underwent simultaneous echo-Doppler and hemodynamic studies during sinus rhythm and induced sustained stable monomorphic VT. The VT cycle length was 447 +/- 92 ms (mean +/- SD). During VT, cardiac index fell from 2.32 +/- 0.54 to 1.62 +/- 0.63 L/min/m2 (p less than 0.001), and systemic systolic blood pressure fell from 129 +/- 18 to 107 +/- 18 mm Hg (p less than 0.001), while left ventricular end-diastolic pressure showed a rising trend from 9 +/- 7 to 15 +/- 12 mm Hg, and pulmonary artery wedge pressure rose from 10.2 +/- 1.6 to 24.2 +/- 2.3 mm Hg (p less than 0.005). By echo-Doppler the ejection fraction and the presence and degree of valvular regurgitation were not significantly changed during VT. The mean maximal left ventricular inflow tract velocities, mean time velocity integrals, and the mean time velocity integrals normalized for heart rate (measures of left ventricular diastolic filling) decreased from 0.59 +/- 0.074 to 0.40 +/- 0.053 m/s (p less than 0.05), from 0.12 +/- 0.029 to 0.021 +/- 0.012 m (p less than 0.001), and from 7.43 +/- 1.20 to 3.21 +/- 1.49 m x beats/min (p less than 0.001) during VT, respectively. We conclude that hemodynamic changes during stable sustained VT are neither associated with significant changes in systolic left ventricular function nor related to valvular regurgitation and are likely caused by impaired left ventricular diastolic filling.

Aged↗

[Correlation of stimulus-induced ventricular echo beats and left ventricular function in patients without ventricular tachycardia].

110 patients (105 male, 5 female, mean age +/- S.D.: 52.9 +/- 5.9 years) with and without coronary artery disease were prospectively studied by programmed right ventricular stimulation (single and double premature stimuli during sinus rhythm and a paced ventricular drive of rates of 120, 140, 160 and 180 b.p.m.). The incidence of ventricular echobeats (VE) was correlated with angiographic and electrocardiographic findings. The end of the stimulation protocol was reached as soon as four or more ventricular echobeats were initiated. 0 to 3 VE occurred in 61/110 patients, 4-9 VE in 31 patients (28%), and greater than or equal to 10 VE were induced in 16 patients. Four or more VE were initiated in 68% of cases up to a paced ventricular rhythm of 120 b.p.m. after one or two premature stimuli. Patients with abnormal results of stimulation showed a tendency to an increase in the frequency of ventricular extrasystoles and couplets during long-term ECG recording. 86% of the patients with normal angiographic findings had 0-3 VE and 14% greater than or equal to 4 VE. In 49% of the patients with abnormal left ventricular function, 0-3 VE and in 51%, greater than or equal to 4 VE could be induced. The type of left ventricular contraction abnormality was significantly correlated to the results of programmed ventricular stimulation. greater than or equal to 4 VE were observed in 74% of patients with anterior wall myocardial infarction. Patients with inferior wall myocardial infarction had greater than or equal to 4 VE in 54% of cases. Ventricular tachycardia was induced in 30% of patients with anterior and in only 12% of patients with inferior wall myocardial infarction (n.s.). To conclude, this prospective study has shown a correlation between the incidence of inducible ventricular echobeats in response to programmed ventricular stimulation and left ventricular function. The prognostic significance of these findings has to be assessed.

Electric Stimulation↗

Amrinone therapy in patients with heart failure. Lack of improvement in functional capacity and left ventricular function at rest and during exercise.

Short-term amrinone therapy has been shown to exert beneficial hemodynamic effects in patients with heart failure. To determine whether this improvement persists longer, the effects of maximally tolerated doses of amrinone on exercise duration, oxygen consumption, and left ventricular function and volumes were examined during maintenance therapy. After four weeks of amrinone therapy, 75 to 150 mg three times a day (mean 292 +/- 70 mg daily), treadmill exercise duration, maximal oxygen consumption, and functional class were unchanged from control values. Radionuclide-derived ejection fraction and end-diastolic and end-systolic volumes were not altered at rest or during maximal supine exercise. Similarly, significant changes in echocardiographic end-systolic and end-diastolic dimensions did not occur. This lack of clinical benefit on functional capacity and left ventricular function, together with frequent adverse reactions, will limit the application of amrinone in the treatment of heart failure. These findings are relevant to the investigation of amrinone-like derivations presently being studied for the treatment of heart failure. Before their release, these agents will require careful evaluation and demonstration of a therapeutic action during maintenance therapy, together with a low incidence of adverse reactions.

Administration, Oral↗

[Relationship between exercise capacity and left ventricular function at rest in patients with heart insufficiency: radionuclide continuous monitoring of left ventricular function].

PURPOSE: To evaluate the relationship of systolic and diastolic function at rest to exercise capacity. MATERIAL AND METHODS: Seventeen patients with ischemic heart failure were included in the study. Ambulatory left ventricular monitoring at rest and during upright exercise with combined analysis of pulmonary gas exchange was performed. Ejection fraction, end-diastolic volume, end-systolic volume, stroke volume, cardiac output, and peak filling rate were measured. RESULTS: Significant positive correlations were found between rest ejection fraction and peak oxygen consumption (r = .60, p < .01), peak cardiac output (r = .77, p < .0001), peak stroke volume (r = .67, p < .005), and peak ejection fraction (r = .69, p < .005). On the other hand, peak filling rate at rest showed a significant inverse correlation with peak end-diastolic (r = -.48, p < .05) and end-systolic (r = -.66, p < .005) volumes. The patients were then subgrouped into two groups according to their rest ejection fraction (lower or higher than 40%). In the group with ejection fraction less than 40% a significant correlation was observed between rest ejection fraction and both peak stroke volume (r = .66, p < .05) and peak ejection fraction (r = .69, p < .05). In the same group of patients an inverse correlation was found between peak filling rate and both end-diastolic (r = -0.65, p < .05) and end-systolic (r = -.82, p < .005) volumes. CONCLUSIONS: The results of the present study suggest that exercise capacity is related to left ventricular function at rest and that rest diastolic function might be a determinant of left ventricular function during exercise in patients with heart failure.

Exercise Tolerance↗

Drugs or implantable cardioverter-defibrillators in patients with poor left ventricular function?

Poor left ventricular function is a predictor of sudden death. Both antiarrhythmic drugs and implantable cardioverter-defibrillators (ICDs) promise to reduce the sudden death rate in these patients and consequently improve survival. In patients without spontaneous ventricular tachyarrhythmias, only beta-blocking agents and amiodarone have been shown to reduce sudden death and improve survival in some studies, whereas class I antiarrhythmic drugs increased mortality. For patients with documented ventricular tachyarrhythmias, protection against sudden death by serially tested class I antiarrhythmic drugs is at best moderate. There is some evidence suggesting that therapy with class III antiarrhythmic drugs, either amiodarone or dl-sotalol, may reduce sudden death rates and improve overall mortality in comparison to therapy with class I antiarrhythmic drugs. ICDs have been shown to prevent sudden death reliably. In published patient cohorts in which only patients who were not inducible off antiarrhythmic drugs or still inducible on antiarrhythmic drugs received an ICD, the ICD seemed to improve overall survival in comparison to class I antiarrhythmic drugs. A small prospective randomized study that compared a conventional therapy strategy to primary ICD implantations showed an improved outcome with ICDs as therapy of first choice. However, these studies included many patients treated with class I antiarrhythmic drugs considered to be less effective. In matched control studies comparing the ICD to amiodarone or dl-sotalol, less sudden deaths and an improved overall survival could be shown for the ICD in general without stratification for left ventricular function. Thus, in patients with hemodynamically nontolerated ventricular tachyarrhythmias, the ICD seems to improve survival in comparison to class I antiarrhythmic drugs, dl-sotalol, or amiodarone. However, in patients with poor left ventricular function, therapy with ICDs seems to be less cost-effective than in patients with preserved left ventricular function. In patients with very poor left ventricular function who are evaluated for cardiac transplantation, the ICD seems to change only the mode of death from sudden to a nonsudden cardiac death if transplantation cannot be performed soon.

Anti-Arrhythmia Agents↗

Assessment of left ventricular function before and after Fontan's operation for the correction of tricuspid atresia. Changes in left ventricular function determined by left ventricular volume change.

Functional change in the left ventricle was studied in the light of changes in the left ventricular (LV) volume preload before and after Fontan's operation. Six cases with tricuspid atresia (TA) were studied, and they had either types Ib or IIb. The preoperative LV end-diastolic volume index (LVEDVI) was 123 +/- 44 ml/m2, which corresponds to 166% +/- 45% of normal values. This suggests that in TA the preload of the LV volume is increased because of its peculiar hemodynamic situation. After Fontan's operation, the LVEDV decreased by 24.6% to 119.6 +/- 87.7 ml (P = 0.01), which corresponds to 120% +/- 50.9% of normal values. Presenting a striking contrast to the decrease in LVEDV, the postoperative reduction in LV end-systolic volume (LVESV) was approximately 8%. Preoperative and postoperative values for LVESV were 67.1 +/- 50.8 ml and 62 +/- 45.6 ml, thus, the systolic volume was decreased. Because of the small change in LVESV, the ejection fraction (EF) of the left ventricle significantly decreased from 0.61 +/- 0.1 preoperatively to 0.48 +/- 0.1 postoperatively. The cardiac index (CI) remained in the range of 1.9-2.5 l/min/m2 with a mean of 2.2 +/- 0.2 l/min/m2 at 1 month after operation. But, later, improvement in EF was observed in one case, in which the CI increased from 2.5 to 3.2 l/min/m2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Echocardiographic assessment of left ventricular function in left ventricular volume load and the immediate changes after operation.

Cardiac function and changes following surgery was studied with computerized M-mode echocardiography in 12 patients with volume load of the left ventricle. Half of them had congenital lesions, the other half aortic regurgitation. Left ventricular (LV) shortening fraction and LV ejection time were significantly reduced postoperatively and came close to normal mean values. Also cardiac output and LV diameters normalized or at least started its normalization. The computerized values for rates of decrease and increase of left ventricular diameter were reduced postoperatively (p less than 0.01 and p less than 0.05 respectively) compared to elevated preoperative values. The study shows that relief of volume load on the left ventricle immediately leads to normalization of left ventricular function, especially if the myocardium was intact preoperatively.

Adolescent↗

[Ventricular function in hypertrophic cardiomyopathy. Systolic and diastolic ventricular function].

BASIC CONSIDERATION: Hypertrophic cardiomyopathy is defined as a primary myocardial disease associated with a hypertrophic non-dilated left ventricle with no other heart or systemic disease that might lead to hypertrophy of the left ventricle. The leading symptoms are effort-associated angina and dyspnea, rapid fatigue, dizziness and syncope. MAIN POINTS DISCUSSED: The hemodynamic situation is characterized by a hyperdynamic systole and impaired diastole and left-ventricular filling. In the obstructive form, hypertrophy of the basal septum and an anteriorly moving mitral valve during systole result in an end-systolic reduction in the cross-section of the outflow tract associated with considerable intraventricular pressure gradients. Disturbances in the myocardial calcium metabolism are presently suspected to be causally involved in the diastolic function impairment.

Cardiomyopathy, Hypertrophic↗

The value of pixel per pixel multiharmonic Fourier analysis to assess left ventricular function.

Left ventricular systolic and diastolic function can be assessed by peak ejection and filling rates and their time of occurrence. These parameters can be calculated using two different methods: from the global left ventricular time-activity curve analysed with a four harmonic Fourier fit and from each pixel time-activity curve analysed with two and three harmonics (the values being averaged over the left ventricular region of interest). In both cases, values were normalized for heart rate and end diastolic counts. A study was conducted in a series of 11 patients (six without and five with a previous myocardial infarction but a normal left ventricular function) examined at baseline and during an i.v. dobutamine infusion, at a dose known to increase both peak ejection and filling rates. During dobutamine infusion, analysis of global left ventricular time-activity curve demonstrated a statistically significant increase in both peak ejection and filling rates, but the local analysis showed a more significant increase of these parameters. To assess ventricular function, a local harmonic analysis can be used and appears to be a more sensitive approach than analysis of the global left ventricular time-activity curve. The local analysis provides spatial mapping and a histogram of the parameters which can be used as parametric images to describe systolic and diastolic function.

Dobutamine↗