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PubMed1993

Evaluation of clinical variables as predicators of left ventricular function in acute myocardial infarction.

In 43 rural patients, all survivors of acute Myocardial infarction, left ventricular function was studied by 2-D echocardiography and evaluated in relation to 18 clinical predictors of left ventricular function. The mean left ventricular ejection fraction (LVEF) was 41.53 +/- 12.92% as compared to 70.02 +/- 7.02% in 506 healthy controls. LVEF was dichotomised at < 40% (n = 24) and > 40% (n = 19). Out of various clinical variables analysed following were found to be strong predictors of low LVEF. S3 gallop (p < 0.001) pulmonary rates (p < 0.001); Creatine phosphokinase > 200 I.U. (p < 0.001); Cardiomegaly on X-ray (p < 0.001); pulmonary congestion on chest X-ray (p < 0.001); and proportional pulse pressure (p < 0.001). There was a stepwise decline in the LVEF for each additional clinical variable. The over all predictive accuracy was 90%. It is concluded that readily obtainable clinical variables provide a useful bedside method of estimating LVEF after acute myocardial infarction.

Aged↗
PubMed1992

Preoperative and postoperative right ventricular function during exercise in patients with mitral stenosis.

To elucidate the effects of mitral valve surgery on right ventricular function in 11 patients with mitral stenosis, pre- and postoperative right ventricular function were quantified using gated equilibrium blood pool radionuclide ventriculography at rest and during exercise. The preoperative right ventricular ejection fraction was 39 +/- 4% at rest and 36 +/- 9% during exercise, which during exercise was lower than control values (51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction was lower during exercise than at rest, postoperative right ventricular ejection fraction during exercise was lower than normal values (42 +/- 3% versus 51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction did not decrease during exercise, the postoperative right ventricular ejection fraction was within normal limits during exercise (54 +/- 5%). In addition, postoperative right ventricular ejection fraction during exercise increased to normal values in patients whose preoperative right ventricular ejection fraction during exercise had been 40% or higher. Preoperative peak ejection rate was -1.81 +/- 0.19 EDV/sec at rest and -1.72 +/- 0.39 EDV/sec during exercise, which during exercise was lower than control values (-2.44 +/- 0.53 EDV/sec) (p < 0.01). Postoperatively, peak ejection rate during exercise (-2.50 +/- 0.37 EDV/sec) increased (p < 0.05) to normal levels. Preoperative peak filling rate was 1.61 +/- 0.47 EDV/sec at rest and 1.88 +/- 0.54 EDV/sec during exercise, which during exercise was lower than control values (2.58 +/- 0.62 EDV/sec) (p < 0.01). Postoperatively, peak filling rate during exercise (2.82 +/- 0.62 EDV/sec) increased (p < 0.05) to normal values in all patients. Preoperative changes in both right ventricular ejection fraction and peak ejection rate from rest to exercise inversely correlated with the preoperative pulmonary vascular resistance at rest (right ventricular ejection fraction, r = -0.79, p < 0.005; and peak ejection rate, r = -0.67, p < 0.05). In conclusion, right ventricular systolic function improved in about half of the patients with mitral stenosis, and diastolic function improved in all patients during exercise following surgery. When the preoperative pulmonary vascular resistance was elevated, the right ventricular systolic dysfunction persisted.

Adult↗
PubMed1999

Angiographic frame counts 90 minutes after streptokinase predict left ventricular function at 48 hours following myocardial infarction.

OBJECTIVE: To assess whether the 90 minute corrected thrombolysis in myocardial infarction frame count (CTFC) in the infarct related artery predicts left ventricular function at 48 hours in patients with myocardial infarction treated with aspirin, streptokinase, and either heparin or Hirulog. DESIGN AND SETTING: Analysis of 251 patients with acute myocardial infarction enrolled in the international, multicentre Hirulog early reperfusion/occlusion (HERO-1) trial, who underwent both 90 minute coronary angiography and 48 hour left ventriculography. MAIN OUTCOME VARIABLES: The CTFC was determined in the infarct related artery 90 minutes after starting intravenous streptokinase (1.5 x 106 U over 30 to 60 minutes), and compared with indices of left ventricular function assessed by contrast ventriculography at 48 hours. RESULTS: A CTFC of </= 27 frames (previously reported mean + 2 SD in coronary arteries of patients without acute infarction) occurred in 29% of infarct related arteries, and was associated with a lower infarct zone mean chord score (-2.06 v -2.54, p = 0.01), a lower fraction of chords > 2 SD below normal (37% v 51%, p = 0.005), and trends towards higher left ventricular ejection fractions (60.9% v 58.2%, p = 0.11) and lower end systolic volumes (50.1 ml v 55.9 ml, p = 0.23). A CTFC of </= 40 at 90 minutes occurred in 50% of infarct related arteries, and was associated with a significantly lower mean chord score (-2.20 v -2.60, p = 0.02), a smaller fraction of chords > 2 SD below normal (41% v 52%, p = 0.025), a smaller end systolic volume (49.1 ml v 59.3 ml, p = 0.02), and a higher left ventricular ejection fraction (60.4% v 56.5%, p = 0.03). CONCLUSIONS: The 90 minute CTFC predicts left ventricular function at 48 hours following streptokinase. The CTFC associated with better ventricular function may be higher than values determined from a non-infarct population.

Coronary Angiography↗
PubMed1988

Left ventricular function of survivors of a first complicated acute myocardial infarction. A prehospital discharge cross-sectional echocardiographic study.

To assess the left ventricular function of patients who suffer from post-infarction angina and left ventricular failure in the coronary care unit, 79 consecutive survivors (mean age 48 years) of a first acute myocardial infarction were prospectively studied and followed-up for a mean 18- (10-34) month period. Forty-seven had an uncomplicated infarction, 17 suffered from post-infarction angina and 15 had left ventricular failure. The left ventricular function of these patients prior to discharge from hospital was assessed by cross-sectional echocardiography and radionuclide angiography. Analysis of left ventricular wall motion was performed in all patients using a 11-segment model of the left ventricular. The ejection fraction was determined by echocardiography in 47 patients and by radionuclide angiography in 50. The mean echocardiographic wall motion score of post-infarction angina patients (4.8 +/- 0.8) (+/- SEM) was lower than that of patients with left ventricular failure (9.5 +/- 0.5) (P less than 0.001), but was not different from patients suffering uncomplicated infarctions (4.6 +/- 0.3). The mean echocardiographic ejection fraction was also similar in post-infarction angina (45.3 +/- 4.0; n = 16) and patients with uncomplicated infarction (51.9 +/- 2.7; n = 17), but was lowest in the group of patients with left ventricular failure (35.1 +/- 3.3; n = 14). Similarly, the radionuclide ejection fraction of patients with post-infarction angina (41.4 +/- 3.4; n = 17) and patients with uncomplicated infarction (45.6 +/- 2.7; n = 19) did not differ, but was lower in patients with left ventricular failure (25.9 +/- 2.8; n = 14). The echocardiographic ejection fraction correlated with that obtained by radionuclide angiography in all 46 patients (r = 0.71, P less than 0.001). The wall motion score correlated with the radionuclide ejection fraction in all 50 patients (r = -0.73, P less than 0.001) and with the echocardiographic ejection fraction in 47 patients (r = -0.55, P less than 0.001). During follow-up, 3 (18%) patients suffering post-infarction angina and 2 (13%) with left ventricular failure died. New infarction was seen in 2 (12%) and 1 (7%) patients in these groups, respectively. We conclude that the left ventricular function of patients who suffer from post-infarction angina in the coronary care unit is good, but is impaired in those with even transient left ventricular failure. Echocardiographic assessment of cardiac function prior to hospital discharge was highly successful and may be performed in all such patients.

Adult↗
PubMed1989

Model studies of the contribution of ventricular interdependence to the transient changes in ventricular function with respiratory efforts.

The effects of variations in intrathoracic pressure on left ventricular function were studied using a mathematical model of the circulation. The variations in intrathoracic pressure directly affect the left ventricular afterload, and indirectly alter left ventricular filling by changing the right ventricular volume. The decrease in intrathoracic pressure with sustained inspiratory efforts increased the left ventricular afterload and thus reduced the left ventricular stroke volume. Secondary to the reduction in stroke volume, the left ventricular end systolic and end diastolic volumes increased. Decreasing intrathoracic pressure also increased the systemic venous return, thereby increasing right ventricular volume. The model predicted that an enlarged right ventricular volume would, through diastolic ventricular interdependence, immediately reduce the left ventricular end diastolic volume (which in turn reduced the left ventricular stroke volume), while through systolic ventricular interdependence it would increase left ventricular stroke volume and reduce left ventricular end systolic volume. An increased right ventricular volume would also increase right ventricular stroke volume and after a delay of a few heart beats raise left ventricular end diastolic and stroke volumes. The net effect of respiratory variations in intrathoracic pressure on left ventricular function would be a combination of these effects. Thus on sustained inspiration the left ventricular stroke volume initially decreased (left ventricular afterload and diastolic interdependence secondary to the increase in right ventricular volume partly counteracted by the effects of systolic interdependence), followed by an increase as the increased venous return reached the left ventricle. The model indicated that the response to a forced expiratory effort was not simply the opposite of the inspiratory response, since the increase in intrathoracic pressure during a forced expiration is accompanied by increases in abdominal pressure. On sustained expiration the left ventricular stroke volume initially increased, with no significant initial change in end diastolic volume. The cardiovascular response to respiration is complex, and model studies can help to isolate and identify the various components involved.

Computer Simulation↗
PubMed1987

Relationship between myocardial norepinephrine content and left ventricular function--an endomyocardial biopsy study.

To analyze the relationships between left ventricular function, catecholamine concentrations in plasma and myocardium, and morphological alterations, 20 patients were studied. Fifteen patients had idiopathic dilated cardiomyopathy, and 5 had normal left ventricular function. All patients underwent right ventricular endomyocardial biopsy to determine muscle fibre thickness, percent volume fraction of interstitium, and myocardial catecholamine content. Blood was sampled to measure plasma catecholamine concentrations, and left ventricular cineangiography was performed to determine global ejection fraction. In a simple correlation analysis a significant correlation was found between left ventricular ejection fraction and myocardial norepinephrine content (r = 0.80, P less than 0.001). Left ventricular ejection fraction was negatively correlated with plasma epinephrine concentration (r- = 0.53, P less than 0.02), and with muscle fibre thickness (r = -0.50, P less than 0.03). Myocardial norepinephrine concentration was negatively correlated with plasma epinephrine (r = -0.62, P less than 0.01). Multiple linear regression analysis revealed a strong correlation between myocardial norepinephrine depletion and left ventricular dysfunction, which was independent of all other variables. These data suggest that myocardial norepinephrine depletion determined from right ventricular endomyocardial biopsies strongly correlates with left ventricular dysfunction in idiopathic dilated cardiomyopathy, and seems to be independent of the degree of muscle fibre hypertrophy, volume fraction of interstitium, and of the increased sympathetic tone.

Biopsy↗
PubMed1980

[Cross-sectional echocardiography applied to the study of the effects of sodium nitroprusside on left ventricular function (author's transl)].

Quantitative measurement of the left ventricular function by means of cross-sectional echocardiography is now well established. The present study suggests that the method could be used to record and assess the effects of vasodilators on the performance of an ischaemic left ventricle. Congestive heart failure was induced in 3 dogs by occluding the anterior interventricular artery, and sodium nitroprusside was injected intravenously. Haemodynamic and echocardiographic data were recorded simultaneously. Using two echotomographic sections at a right angle, changes in left ventricular volume and stroke volume were calculated from the equation V = 5/6 AL, where V is the volume, A the surface and L the length of the ventricle. The application of this non-invasive technique to the analysis of global and regional left ventricular function in various clinical situations is discussed.

Animals↗
PubMed1979

Scintigraphic evaluation of left ventricular function.

Scintigraphic studies, performed with a scintillation camera and a small computer, can provide information concerning total and regional left ventricular function (Table 1). Of the two types of studies (first-pass and gated blood pool) the gated blood study is more appropriate for studies of regional function than is the first-pass method. Ejection fraction, an index of global ventricular function, is measureable from first-pass or gated blood pool studies. Gated blood pool studies allow visual assessment of net ventricular function as well as the local functional status of the myocardium. Multiple gated blood pool studies allow computation of ventricular volume curves, from which ejection fraction and ejection rate may be determined. There are several areas of application for these relatively inexpensive and virtually noninvasive studies. In patients with recent myocardial infarction, visual assessment of regional ventricular wall motion and quantitative measurement of ejection fraction provide additional prognostic information, especially when measured serially. In patients with coronary artery disease, the development of regional ventricular wall motion abnormalities may indicate local myocardial ischemia. Consequently, scintigraphic imaging may add significantly to the usefulness of exercise stress testing.

Heart Ventricles↗
PubMed1997

Nitric oxide has little effect on acute pulmonary hypertension and right ventricular function during acute respiratory distress syndrome.

OBJECTIVE: To evaluate the effect of nitric oxide (NO) on acute pulmonary hypertension and right ventricular function in patients with acute respiratory distress syndrome. DESIGN: A prospective clinical study. PATIENTS: Ten patients in the respiratory and surgical intensive care units were used. They met the criteria for acute respiratory distress syndrome and were significantly hypoxic. They were all ventilator-dependent at the time of the study. INTERVENTION: NO was delivered to the patients in 5, 10, 20 and 30 ppm doses for 30 minutes at each concentration. The dosing was not randomised. MEASUREMENTS AND RESULTS: The general and central haemodynamics were measured. Right ventricular function and interaction with the pulmonary artery impedance (Ea) were quantified with the ratio of right ventricular stroke work index/Ea. NO did not decrease the raised pulmonary artery pressure found in all of the patients. Right ventricular coupling to the circulation did not improve during the administration of NO. CONCLUSION: NO did not relieve the acute pulmonary artery hypertension associated with acute respiratory distress syndrome. As a consequence of this, right ventricular function failed to improve during the administration of NO.

Acute Disease↗
PubMed1988

Effect of positive end-expiratory pressure on right ventricular performance. Importance of baseline right ventricular function.

Thirty-six patients with diverse baseline right ventricular function were evaluated during incremental positive end-expiratory pressure (PEEP) application. Right heart pressures, cardiac output, right ventricular ejection fractions, and ventricular volumes were obtained at each PEEP level. Right ventricular peak systolic pressure-end-systolic volume relations were analyzed as an index of contractile function. Patients with severely depressed baseline right ventricular ejection fractions (30 percent or less) had an increase in end-diastolic (270 +/- 74 to 391 +/- 76 ml, 0 to 20 cm water (H2O) PEEP, p less than 0.05) and end-systolic volumes (210 +/- 70 to 321 +/- 70 ml, 0 to 20 cm H2O PEEP, p less than 0.05). These patients also had a decline in estimated right ventricular contractile function at 20 cm H2O PEEP as estimated by the slope of systolic pressure-volume relations (0.12 to 0.04 mm Hg/ml, 0 to 15 and 15 to 20 cm H2O PEEP, respectively, p less than 0.05). Patients with normal (40 percent or more) or moderately depressed (31 to 40 percent) baseline right ventricular ejection fractions had no change in right ventricular volumes or estimated contractile function. Therefore, the effect of PEEP on right ventricular function differs depending on the baseline right ventricular ejection fraction.

Adult↗
PubMed1994

The role of right and left ventricular function in the ventilatory response to exercise in chronic heart failure.

BACKGROUND: Right ventricular function may be an important determinant of exercise capacity, peak oxygen consumption (VO2), and the ventilatory response to carbon dioxide production (VE/VCO2 relation) in patients with chronic heart failure (CHF). METHODS AND RESULTS: We studied the role of right ventricular function in CHF and also investigated the effects of absent right ventricular reserve in patients previously operated on with Fontan's procedure by measuring metabolic gas exchange during exercise in five groups of patients: (1) 10 patients who had previously undergone Fontan's procedure for congenital heart disease in whom the right ventricle is not functional; (2) 11 age-matched control subjects with dilated cardiomyopathy (DCM); (3) 15 age-matched normal subjects; (4) 42 patients with CHF; and (5) 16 age-matched control subjects. Left and right ventricular ejection fractions (LVEF and RVEF) were measured by radionuclide ventriculography in group 4. In the young subjects, the VE/VCO2 slope was lower in the control subjects than in the other two groups, being 24.4 +/- 4.3 against 33.3 +/- 6.6 in group 1 (P < .001) and 29.6 +/- 8.1 in group 2 (P < .05). The correlation between peak VO2 and VE/VCO2 was -0.80 (P = .005) in group 1 and -0.76 (P = .007) in group 2. In the older age groups, the VE/VCO2 slope was significantly greater (38.0 +/- 14.9 versus 25.4 +/- 3.7; P < .001) in the heart failure group (group 4). In neither control group was there a significant relation between peak VO2 and VE/VCO2 slope. In group 4, the relation between peak VO2 and VE/VCO2 was similar to that seen for groups 1 and 2. LVEF was 24.3 +/- 14.1%, and RVEF was 32.5 +/- 13.1%. There was no correlation between either RVEF or LVEF and peak VO2 or VE/VCO2 slope in the heart failure group. CONCLUSIONS: The relation between excessive ventilation and reduction in peak oxygen consumption is present in patients with no functioning right ventricle. RVEF is not a determining feature of either exercise capacity or the excessive ventilatory response in CHF.

Adult↗
PubMed1989

[Digital subtraction angiography and Fourier analysis of the left ventriculography: new methods of analyzing left ventricular function].

To evaluate two new methods of analyzing left ventricular function, digital subtraction left ventriculography (DSLV) and Fourier analysis of left ventriculography (FALV) were performed after conventional left ventriculography (LV) in 17 consecutive catheterized cases. Ejection fraction of FALV and LV corresponded closely with the correlation coefficient of 0.906, while segmental wall motion corresponded less with the range of correlation coefficients from 0.56 for the apical segment to 0.94 for the anterior wall. In 10 cases with asynergic segments of the left ventricle, Fourier analysis showed less hypokinesis in four (all had hypokinesis at the septal segment), the same degree in five and more in one case, suggesting the possibility of FALV to evaluate three-dimensional left ventricular function in a single projection.

Angiography, Digital Subtraction↗
PubMed2001

Predictors of improvement in left ventricular function after percutaneous revascularization of occluded coronary arteries: a report from the Total Occlusion Study of Canada (TOSCA).

BACKGROUND: The Total Occlusion Study of Canada (TOSCA) is a multicenter, randomized trial evaluating the effect of stenting with > =1 heparin-coated stent on long-term patency after percutaneous coronary intervention by balloon angioplasty of occluded coronary arteries. The purpose of the current study was to compare the effect of stenting and balloon angioplasty on global left ventricular ejection fraction (LVEF) and regional wall motion and to examine what clinical and angiographic factors may have an effect on left ventricular function in this setting. METHODS AND RESULTS: Analysis at the core angiographic laboratory of paired baseline and follow-up left ventricular angiograms, as well as target vessel patency, was possible in 244 of 410 cases. An improvement in LVEF was observed in the entire group (59.4% +/- 11% to 61.0% +/- 11%, P =.003). The LVEF change was +1.84 +/- 7.54 in the stent group (P =.009) and 1.28 +/- 8.16 in the percutaneous transluminal coronary angioplasty group (P =.085). There was no significant intergroup difference. Patients with duration of occlusion < or =6 weeks had an improvement in LVEF (+2.98 +/- 8.68, P =.0006), whereas those with an occlusion duration of > 6 weeks had no improvement (+0.48 +/- 7.01, P not significant). Multivariate analysis revealed baseline LVEF <60%, duration of occlusion < or =6 weeks, and Canadian Cardiology Society angina class I or II to be independent predictors of improvement in LVEF. CONCLUSIONS: The restoration of coronary patency of nonacute occluded coronary arteries is associated with a small but significant improvement in regional and global left ventricular function, especially in patients with recent occlusions and depressed left ventricular function. In spite of significant effect on long-term patency, stenting of nonacute coronary occlusions does not result in significantly better left ventricular function compared with balloon angioplasty in this setting.

Angioplasty, Balloon, Coronary↗
PubMed1994

[Action of Astragalus membranaceus on left ventricular function of angina pectoris].

The action on left ventricular function of Astragalus Membranaceus (AM), a Qi-tonic, in 20 patients with angina pectoris was studied by means of Doppler Echocardiogram (DEC). It showed that cardiac output increased from 5.09 +/- 0.21 to 5.95 +/- 0.18 L/min 2 weeks after AM was administered (P < 0.01), and no improvement of left ventricular diastolic function appeared. Adenosine triphosphatase activity was not inhibited by using AM, which was different from that of digitalis.

Adenosine Triphosphatases↗
PubMed1991

Left ventricular function in patients with stable systemic lupus erythematosus.

Echocardiography was used to compare the left ventricular function of 43 female patients with stable systemic lupus erythematosus with 93 healthy females in 3 age groups. Left ventricular systolic function was evaluated by the left ventricular ejection fraction and left ventricular diastolic function was evaluated by the diastolic descent rate of the anterior mitral leaflet (DDR), the ratio of mean systolic velocity to mean diastolic velocity in the left ventricular posterior wall (D/S ratio) and the ratio of peak mitral inflow velocity during the atrial filling period to that in the early filling period (A/E ratio). The left ventricular ejection fraction was not significantly different between patients and normal subjects. However, left ventricular diastolic function evaluated by these indexes in patients was different from normal subjects. These data suggest that left ventricular diastolic function is lower in patients with stable systemic lupus erythematosus than in normal subjects. It appears to deteriorate progressively with age. However, left ventricular systolic function remains normal.

Adolescent↗
PubMed2000

Limitations of the transpulmonary indicator dilution method for assessment of preload changes in critically ill patients with reduced left ventricular function.

OBJECTIVE: We examined whether intrathoracic blood volume (ITBV) and total end-diastolic volume (TEDV), determined by the transpulmonary indicator dilution technique, adequately reflect preload changes during fluid administration in patients with reduced left ventricular function. DESIGN: A prospective, controlled, clinical study. SETTING: Medical intensive care unit in a university hospital. PATIENTS: A total of 18 sedated, mechanically ventilated, and moderately hypovolemic intensive care unit patients, eight with reduced left ventricular function (ejection fraction area, 24.9+/-8.0%, group A), ten with normal left ventricular function (ejection fraction area, 57.6+/-13.0%, group B). INTERVENTIONS: Continuous crystalloid infusion over 120 mins at a constant rate of 8 mL/kg/30 mins. MEASUREMENTS AND MAIN RESULTS: Stroke volume index, central venous pressure, pulmonary artery occlusion pressure (PAOP), TEDV, and ITBV were determined simultaneously at baseline and serially every 30 mins during continuous crystalloid infusion. A similar series of measurements was obtained during control conditions. Performance of various variables during fluid administration was assessed by time correlation analysis. Sensitivity for various variables defined as the ability to detect increasing amounts of administered fluid in individual patients was calculated. All examined variables increased during fluid administration and were unaffected during the control period. Mean time correlation (r2) was significantly higher for pressure monitoring (central venous pressure, r2 = 0.8281; PAOP, r2 = 0.5476) than for volume variables (TEDV, r2 = 0.0256; ITBV, r2 = 0.0729) in group A and was high for all variables in group B (central venous pressure, r2 = 0.7056; PAOP, r2 = 0.6241; TEDV, r2 = 0.49; ITBV, r2 = 0.4225). Sensitivities for central venous pressure, PAOP, TEDV, and ITBV after 120 min were 63%, 75%, 25%, and 25% in group A and 90%, 100%, 60%, and 60% in group B, respectively. CONCLUSION: This study demonstrates limitations of the transpulmonary indicator dilution technique for monitoring of intravascular volume in patients with reduced left ventricular function.

Critical Care↗
PubMed1997

Acute hemodynamic effects of intravenous ibutilide in patients with or without reduced left ventricular function.

Many antiarrhythmic agents have adverse hemodynamic effects which limit their use in patients with impaired ventricular function or during tachyarrhythmias. Ibutilide is an intravenous, selective class III antiarrhythmic agent that is effective for conversion of atrial fibrillation or flutter. This multicenter, randomized, placebo-controlled, dose-ranging study evaluated the effects of intravenous ibutilide on hemodynamic parameters during invasive monitoring in 47 patients with or without reduced left ventricular ejection fraction (LVEF) > 35% or < or = 35%. Patients received either placebo or ibutilide as a 10-minute loading and a 30-minute maintenance infusion using 1 of the following dosing regimens: placebo then placebo (n = 12); 0.01 then 0.002 mg/kg (n = 12); 0.02 then 0.004 mg/kg (n = 12); or 0.03 then 0.006 mg/kg (n = 11). Ibutilide significantly increased QT and QTc intervals in a dose-related manner with mean increases ranging from 51 to 99 ms, but did not alter the PR interval or QRS duration. During ibutilide infusion, a few small but statistically significant changes from baseline in several hemodynamic variables were present. However, the changes in cardiac output, pulmonary artery or capillary wedge pressures, blood pressure, or heart rate in patients receiving ibutilide were not significantly different from the changes in patients receiving placebo. Thus, ibutilide did not cause clinically important adverse hemodynamic effects, even in patients with depressed ventricular function. One patient developed 2 episodes of nonsustained torsades de pointes during ibutilide. These results demonstrate that with careful monitoring for proarrhythmia, ibutilide can be used safely from a hemodynamic standpoint in the acute treatment of arrhythmias, even in patients with reduced ventricular function.

Adult↗
PubMed1993

Right ventricular function at rest and during exercise in chronic obstructive pulmonary disease. Comparison of two radionuclide techniques.

Right ventricular function was assessed in 24 patients with COPD, at rest and during submaximal exercise, using both technetium-99m (99mTc) blood-pool and krypton-81m (81mKr) equilibrium ventriculography. Technetium-99m right ventricular ejection fraction (RVEF) at rest was lower than 81mKr RVEF (0.39 +/- 0.12 and 0.54 +/- 0.08, respectively; p < 0.001). During submaximal exercise, there was no increase in RVEF using either imaging technique. This observation contrasted with an increase in RVEF in a group of age-comparable normal subjects during modest submaximal exercise. An inability to obtain spatial separation of right heart structures using 99mTc imaging leads to a value for RVEF that is consistently lower than that measured using 81mKr ventriculography. Resting RVEF is well preserved at rest in most patients with COPD. In contrast to normal subjects, many show an inability to augment right ventricular function during exercise that may contribute to the reduced exercise capacity observed in these patients.

Aged↗