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PubMedDate not supplied

An estimate of the prevalence of reversible left ventricular dysfunction in patients referred for coronary artery bypass surgery.

BACKGROUND: The prevalence of reversible left ventricular function through revascularization has been difficult to assess because of the referral bias inherent in patients undergoing viability-targeted preoperative testing. METHODS AND RESULTS: Rest and exercise gated equilibrium radionuclide angiography was performed in 86 patients within 6 months before and any time after coronary artery bypass. Clinical characteristics were recorded for each patient before each of the two radionuclide ventriculograms. Global left ventricular ejection fraction (LVEF) was calculated for each patient at rest. A definite change in LVEF was defined as 0.08 or more points and a probable change as 0.04 or more points. Only patients with a resting LVEF of 0.50 or less were eligible for the study. There was no significant group change in LVEF (0.39 +/- 0.08 before surgery vs 0.38 +/- 0.11 after surgery; difference not significant). However, a definite improvement in LVEF was seen in 18 patients (21%) and a probable change in an additional 10 (12%). Consequently, one third of the patients had at least a probable improvement in resting left ventricular function. These prevalences were not related to any change in medical therapy. CONCLUSION: According to a test not specifically designed to evaluate myocardial viability, the prevalence of reversible left ventricular dysfunction is not uncommon, occurring in up to one third of patients referred for coronary revascularization.

Confounding Factors, Epidemiologic↗
PubMed1996

Impact of left ventricular dysfunction on cytokines, hemodynamics, and outcome in bypass grafting.

BACKGROUND: Although patients with reduced left ventricular ejection fraction undergoing cardiac operation experience a higher rate of perioperative complications, the contribution of proinflammatory cytokines released during extracorporeal circulation is not well defined. METHODS: We compared arterial and mixed venous levels of interleukin-6, tumor necrosis factor-alpha, soluble interleukin-2 receptor, and interleukin-2 at 10 points in time (24 hours before until 48 hours after extracorporeal circulation) in 21 patients with an ejection fraction of less than 0.45 (study group) to 15 patients with an ejection fraction of more than 0.55 (control group) undergoing elective coronary artery bypass grafting. The study and control group differed with regard to left ventricular ejection fraction (0.37 +/- 0.05 versus 0.66 +/- 0.11, p < 0.05) and reperfusion time (35 +/- 42 minutes versus 18 +/- 4 minutes, p = 0.07), but not age, sex, vessel involvement, number of grafts performed, cross-clamp time, extracorporeal circulation time, core temperature, and duration of ventilation. RESULTS: Six patients in the study group required mechanical support and 1 died. There were no complications in the control group. In the study group, there were higher preoperative interleukin-2 and tumor necrosis factor-alpha levels and a higher maximum cytokine response to extracorporeal circulation for interleukin-2, soluble interleukin-2 receptor, interleukin-6, and tumor necrosis factor-alpha (all p < 0.05). Interleukin-6 correlated with duration of extracorporeal circulation, dose of norepinephrine and epinephrine support, pulmonary capillary wedge pressure, mean pulmonary arterial pressure, right atrial pressure, heart rate, cardiac index, and inversely with systemic vascular resistance. Interleukin-6 was highest in patients with complications. Arterial and venous cytokine levels correlated closely. CONCLUSIONS: Preoperative left ventricular dysfunction is associated with a higher degree of proinflammatory cytokine release during elective coronary artery bypass grafting. This response is associated with impaired hemodynamics and a higher incidence of perioperative complications.

Case-Control Studies↗
PubMed2002

Time and frequency analysis of beat-to-beat R-T interval variability in patients with ischaemic left ventricular dysfunction providing evidence for non-neural control of ventricular repolarisation.

BACKGROUND: Determinants of temporal lability in ventricular repolarisation are not fully recognised. We aimed to analyse the sources of RT variability by comparing normal subjects and patients after myocardial infarction (MI) with either depressed or preserved left ventricular (LV) function. METHODS: One hundred and nine patients (27 women, 82 men, aged 51 +/- 9 years) were divided into three groups: 24 patients (pts) with an uncomplicated angiographically proven coronary heart disease (CHD-group), 59 post-MI pts with preserved LV function (LVEF > 40%, PMI-N-group) and 26 post-MI pts with depressed LV function (LVEF < 40%, PMI-L-group). An ECG signal of low-noise 512 heartbeats was recorded using a computer-assisted amplifier (16 bit, 2 kHz). The onset and offset of the R-wave and T-wave were determined automatically. The magnitude of R-R and R-T variability was measured as the standard deviation of all intervals (SD-RR and SD-RT, ms, respectively). Their relationship was quantified by the correlation coefficient r(RT/RR). Power spectral density of RR or RT variability was estimated with the FFT (Welch's averaged periodogram, Hanning window) and frequency relation was quantified using a squared coherence spectrum (SCS). For all spectral and cross-spectral measurements two frequency ranges were considered: high (0.15-0.50 Hz, HF) and low (0.04-0.15 Hz, LF). Spectral power and SCS of RR and RT variability for both ranges (HF(RR), LF(RR), HF(RT), LF(RT), SCS(HF), SCS(LF)), and the ratios LF/HF(RR) and LF/HF(RT) were drawn for comparisons. The central frequency of HF(RR) was considered as the frequency of respiration (f(resp), Hz). RESULTS: In the PMI-L group the SD-RT was significantly greater compared to the remaining groups and accounted for almost 10% of the SDRR. Also, the coefficient r(RT/RR) was weakest in this group. The spectral indices of RR variability were similar in all groups, while the greatest value of the HFRT was observed in the PMI-L group. The SCS(LF) was insignificant in this group, contrary to the CHD and PMI-N groups. Additionally, there were significant negative relationships between f(resp) and spectral indices of RT variability in PMI-patients with depressed LV function. CONCLUSION: A greater beat-to-beat variation in RT interval duration along with increased power of its HF component indicates an important role of respiration in ventricular repolarisation control, while reduced time- and frequency RT-RR relationships seem to relate to an impaired process of ventricular duration adaptation.

Adult↗
PubMed1987

5-Fluorouracil cardiotoxicity: left ventricular dysfunction and effect of coronary vasodilators.

Seven patients developed clinical features simulating myocardial ischemia less than 72 hours after 12 of 13 separate intravenous 5-fluorouracil administrations; 9 episodes were associated with chest pain, 3 with hypotension, 3 with ventricular tachycardia and 1 with cardiogenic shock. Left ventricular dysfunction was demonstrated by echocardiography in 5 separate episodes, 2 with interval improvement upon repeat echocardiograms. Pretreatment with nitrates and/or calcium channel blockers failed to prevent recurrence of cardiotoxicity during 5 of 6 repeat 5-fluorouracil administrations. Therapy with 5-fluorouracil is associated with cardiotoxicity simulating myocardial ischemia with left ventricular dysfunction. Pretreatment with coronary vasodilators may not prevent this phenomenon.

Aged↗
PubMed1995

Mechanism of hemodynamic improvement by dual-chamber pacing for severe left ventricular dysfunction: an acute Doppler and catheterization hemodynamic study.

OBJECTIVES: This study was undertaken to determine the mechanism by which improvement in hemodynamic variables may occur with dual-chamber pacing in patients with severe left ventricular dysfunction. BACKGROUND: Dual-chamber pacing has recently been proposed as a therapeutic alternative for the relief of symptoms in patients with dilated cardiomyopathy. METHODS: Fifteen patients with severe left ventricular systolic dysfunction were studied acutely during atrioventricular (AV) sequential pacing at various AV intervals (60, 100, 120, 140, 180 and 240 ms) with use of combined Doppler velocity curves and pressures obtained by high fidelity manometer-tipped catheters and thermodilution cardiac output. RESULTS: Neither cardiac output nor mean left atrial pressure was significantly different when hemodynamic variables in the baseline state were compared with those during AV sequential pacing at the various AV intervals in all patients. The patients were classified into two groups. In group I (eight patients with PR intervals > 200 ms on the rest 12-lead electrocardiogram), cardiac output was significantly increased when AV sequential pacing at the optimal AV interval to output was compared with that at the baseline state (3.0 +/- 1.0 vs. 3.9 +/- 0.43 liters/min, p = 0.005) because timing of mechanical atrial and ventricular synchrony was optimized. In addition, left ventricular end-diastolic pressure and duration of diastolic filling were increased, and diastolic mitral regurgitation was abolished. In group II (seven patients who had normal AV conduction at rest), cardiac output during AV pacing decreased from the baseline value without change in the diastolic filling period. CONCLUSIONS: Dual-chamber pacing may improve acute hemodynamic variables in selected patients with dilated cardiomyopathy, mainly by optimization of the timing of mechanical atrial and ventricular synchrony. Reestablishment of the optimal diastolic filling period and abolition of diastolic mitral regurgitation may also contribute to hemodynamic improvement.

Aged↗
PubMed2003

Coronary artery bypass surgery in patients with severe left ventricular dysfunction.

OBJECTIVE: The role of coronary artery bypass grafting (CABG) in patients with severe left ventricular dysfunction was evaluated. METHODS: Two hundred and twelve patients (152 men, 60 women; age 35 to 82, mean 55) with ejection fraction (EF) of less than 30% underwent CABG between January 1996 and February 2001 by a single surgeon (SA). They compromised of 12% of 1759 patients operated on in this period. EF ranged from 17% to 30% (mean 25%). Preoperatively 68% had congestive heart failure and 72% had severe angina (CCS 3 or 4). A left main lesion was found in 26% of the cases. The mean number of grafts was 3.18 per patient. The left internal mammary artery (LIMA) was used on 107 patients (50.4%). Preoperative intraaortic balloon pump (IABP) was used on 32 patients (15%). Endarterectomy was performed on 53 patients (25%). The patients were followed for up to 58 months (mean 28.7). RESULTS: Twelve patients died in hospital (5.6%). Survival was 94%, 87%, 80% and 73% at 1, 2, 3 and 4 years respectively. Among the preoperative variables survival was negatively affected by chronic renal failure, older age, congestive heart failure, elevated pulmonary artery pressure and recent myocardial infarction, by means of multivariate analysis. Preoperative IABP support improved the operative mortality significantly (P=0.002). Use of LIMA did not have any influence on survival. CONCLUSION: CABG on patients with poor left ventricular function: (1). Can be performed with an acceptable mortality. (2). Mid term results are encouraging. (3). Preoperative IABP support improves the chance of survival.

Adult↗
PubMed1992

Recruitment strategies in the studies of left ventricular dysfunction (SOLVD): strategies for screening and enrollment in two concurrent but separate trials. The SOLVD Investigators.

SOLVD was a double-masked, placebo-controlled trial whose initial sample size goal was to randomize 6100 participants into two concurrent trials: treatment and prevention. The objective was to determine if participants with severe left ventricular dysfunction (left ventricular ejection fraction < or = 35%, with congestive heart failure (2569) and participants without overt heart failure (4228) had improved survival with angiotensin-converting enzyme inhibitors. Participants were identified from cardiac catheterization, echocardiography and radionuclide laboratories, and inpatient units. The treatment trial recruitment goal was attained 13 months ahead of schedule while recruitment for the prevention trial was extended 11 months beyond the scheduled time. Recruitment of relatively asymptomatic participants with a low ejection fraction in a hospital-based trial necessitated novel strategies. Coronary care units and clinics for follow-up of acute cardiac conditions, not typically employed in studies of chronic diseases, were useful recruitment sources. Different approaches to encourage participation also needed to be employed. Expanding selected entry criteria was evaluated and the success of varying strategies was reviewed. The authors recommend tailoring of strategies to the target population, staffing flexibility, principal investigator involvement, and broad entry criteria in recruitment activities.

Cardiac Output↗
PubMed1989

Left ventricular dysfunction in obstructive lung disease: an echocardiographic and angiographic study of cor pulmonale patients with decreased mitral E-F slope.

Twenty-nine patients with cor pulmonale were investigated by echocardiography and cardiac catheterisation in order to assess the significance of a reduced mitral E-F slope. Seven patients had coronary arterial disease and were therefore excluded from further analysis. Of the remaining 22 patients, 15 had a reduced mitral E-F slope but an otherwise normal mitral valve on echocardiography. They were found to have an increased left ventricular end-diastolic pressure measured at cardiac catheterisation when compared to the other seven patients with cor pulmonale and a normal E-F slope. The patients with a reduced E-F slope had an increased mean right ventricular internal dimension and interventricular septal thickness measured echocardiographically when compared to the patients with a normal E-F slope. Right ventricular dysfunction was suggested in these patients by an increased right ventricular end-diastolic pressure measured at cardiac catheterisation. We discuss possible mechanisms of left ventricular dysfunction and of intracardiac pressure transmission in cor pulmonale, and the implications of these mechanisms for effective management.

Aged↗
PubMed1995

[Transluminal coronary angioplasty in patients with left ventricular dysfunction; immediate and long term results].

Transluminal coronary angioplasty is increasingly performed in patients with left ventricular dysfunction. However, there is little data available concerning the outcome of these patients. The aim of this retrospective study was to assess the immediate and long-term results in 90 patients (76 men and 14 women) with left ventricular ejection fractions < or = 35% (average 29 +/- 5%) undergoing angioplasty between 1980 and December 1992. Eighty-seven patients (96%) had a history of infarction, 27 (30%) had already at least one episode of left ventricular failure and 34 (38%) had unstable angina at the time of angioplasty. The coronary disease was usually multi-vessel. A total of 118 lesions were dilated with a primary success rate of 77% (91/118): 86% (82/95) in non-occlusive stenoses and 39% (9/23) in complete obstructions. The total success rate per procedure was 72% (65/90) with a hospital mortality rate of 5.5% (5 cases). The mean follow-up period was 53 +/- 47 months. Twelve patients died during this period and two were lost to follow-up. The total and cardiovascular mortality at the end of the study was 19% (17/88). Eight of the 71 survivors underwent another revascularisation procedure (4 bypasses and 4 angioplasties); 21 (29%) have stable angina, 50 (71%) have no anginal pain and 61 (86%) have antianginal treatment. The probability of survival at one and four years was 81 +/- 4% and 79 +/- 5%, respectively. A multivariate analysis using the Cox model showed three independent prognostic factors for long-term mortality: triple coronary vessel disease, the best predictive factor, left ventricular ejection fraction and female gender.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2000

Prolonged left ventricular dysfunction occurs in patients with coronary artery disease after both dobutamine and exercise induced myocardial ischaemia.

OBJECTIVE: To determine whether pharmacological stress leads to prolonged but reversible left ventricular dysfunction in patients with coronary artery disease, similar to that seen after exercise. DESIGN: A randomised crossover study of recovery time of systolic and diastolic left ventricular function after exercise and dobutamine induced ischaemia. SUBJECTS: 10 patients with stable angina, angiographically proven coronary artery disease, and normal left ventricular function. INTERVENTIONS: Treadmill exercise and dobutamine stress were performed on different days. Quantitative assessment of systolic and diastolic left ventricular function was performed using transthoracic echocardiography at baseline and at regular intervals after each test. RESULTS: Both forms of stress led to prolonged but reversible systolic and diastolic dysfunction. There was no difference in the maximum double product (p = 0.53) or ST depression (p = 0.63) with either form of stress. After exercise, ejection fraction was reduced at 15 and 30 minutes compared with baseline (mean (SEM), -5.6 (1.5)%, p < 0.05; and -6.1 (2.2)%, p < 0. 01), and at 30 and 45 minutes after dobutamine (-10.8 (1.8)% and -5. 5 (1.8)%, both p < 0.01). Regional analysis showed a reduction in the worst affected segment 15 and 30 minutes after exercise (-27.9 (7.2)% and -28.6 (5.7)%, both p < 0.01), and at 30 minutes after dobutamine (-32 (5.3)%, p < 0.01). The isovolumic relaxation period was prolonged 45 minutes after each form of stress (p < 0.05). CONCLUSIONS: In patients with coronary artery disease, dobutamine induced ischaemia results in prolonged reversible left ventricular dysfunction, presumed to be myocardial stunning, similar to that seen after exercise. Dobutamine induced ischaemia could therefore be used to study the pathophysiology of this phenomenon further in patients with coronary artery disease.

Aged↗
PubMed2002

Normal coronary arteries and isolated, regional, left ventricular dysfunction in myotonic dystrophy: a case report.

Development of cardiomyopathy in myotonic dystrophy is rare. Regional ventricular abnormality in the presence of normal coronary vessels has not been reported in this condition. We describe a case of isolated, regional, left ventricular dysfunction with corresponding defects on nuclear perfusion imaging in a patient with classical myotonic dystrophy and normal coronary arteries.

Adult↗
PubMedDate not supplied

Differential systolic and diastolic effects of beta-adrenergic stimulation in patients with severe left ventricular dysfunction: a radionuclide ventriculographic study.

BACKGROUND: An attenuated inotropic response to beta-adrenergic stimulation has been documented in patients with severely depressed left ventricular (LV) function. Scant data exist regarding the effect of beta-adrenergic stimulation on LV diastolic function in human beings. Our objective was to evaluate the effect of dobutamine infusion on LV systolic and diastolic function in patients with severe ventricular dysfunction. METHODS AND RESULTS: We studied 26 patients (60 +/- 9 years) in stable condition with healed myocardial infarction and LV ejection fraction (EF) less than 35% by radionuclide ventriculography. LVEF, volumes, peak ejection rate (PER), peak filling rate (PFR), and peak systolic pressure-to-end-systolic volume ratio were calculated at the infusion rate of 5 and 10 gamma x kg(-1) x min(-1). At 5 gamma x kg(-1) x min(-1), no changes were observed in heart rate (75 +/- 16 beats/min vs 75 +/- 15 beats/min at rest), LVEF (23% +/- 8% vs 22% +/- 7%), and PER (1.40 +/- 0.48 end-diastolic volume per second [EDV/s] vs 1.30 +/- 0.48 EDV/s); however, a significant increase in PFR was observed (1.11 +/- 0.36 EDV/s vs 0.86 +/- 0.30 EDV/s, P < .01). At 10 gamma x kg(-1) x min(-1), an increase in LVEF (25% +/- 10%, P < .01) and PER (1.60 +/- 0.57 EDV/s, P < .01) was observed; PFR (1.25 +/- 0.36 EDV/s, P < .05) also increased, whereas heart rate (78 +/- 18 beats/min) was unchanged. No significant changes in LV volumes or in indices of LV contraction synchronicity were observed during infusion. Finally, the peak systolic pressure-to-end-systolic volume ratio was unchanged at 5 gamma x kg(-1) x min(-1) and significantly increased at 10 gamma x kg(-1) x min(-1). CONCLUSIONS: In stable patients with ischemic heart disease and severe LV dysfunction, beta-adrenergic stimulation may still induce a positive lusitropic response, despite attenuated inotropic and chronotropic responses; moreover, the effects on diastolic function occur earlier than those on systolic function.

Adrenergic beta-Agonists↗
PubMed2000

Asymptomatic left ventricular dysfunction in the community.

The syndrome of chronic heart failure (CHF) is usually attributable to left ventricular dysfunction (LVD), which is most commonly systolic in nature. Many patients who go on to develop heart failure pass through a phase in which they have significant systolic dysfunction but lack clinical symptoms and signs: so-called asymptomatic LVD (ALVD). Treatment of this asymptomatic phase with angiotensin-converting enzyme inhibitors can delay the progression to CHF and ameliorate its substantial morbidity and mortality. This article reviews the epidemiology of ALVD. ALVD is at least as prevalent as CHF, is mainly caused by ischemic heart disease, significantly impairs effort capacity, reduces quality of life, and is associated with a substantial mortality rate. As such, it would appear to satisfy many of the criteria required to screen for a disease. The natriuretic peptide hormones (atrial natriuretic peptide and brain natriuretic peptide ) are elevated in subjects with ALVD. BNP, in particular, has acceptable accuracy to detect LVD in the general population. In particular, it has a high negative predictive value meaning a low concentration makes the presence of significant LVD highly unlikely. As such it has the potential to be a cost-effective means of filtering subjects suspected of having LVD and allowing more appropriate use of tertiary referrals for specialist assessment and detailed echocardiography.

Disease Progression↗
PubMed1986

Atrial natriuretic peptide in chronic heart failure in the rat: a correlation with ventricular dysfunction.

To assess the relation between atrial natriuretic peptide and ventricular dysfunction, we simultaneously measured both atrial and plasma immunoreactive atrial natriuretic peptide concentrations in rats 4 weeks after myocardial infarction induced by left coronary artery ligation. When compared to controls (n = 39), rats with infarction (n = 16) had markedly elevated plasma immunoreactive atrial natriuretic peptide concentrations (1205.8 +/- 180.9 vs. 126.7 +/- 8.9 pg/ml, p less than 0.001) and reduced immunoreactive atrial natriuretic peptide concentrations in right and left atria (31.4 +/- 4.6 vs. 61.2 +/- 3.2 ng/mg, p less than 0.001; 14.9 +/- 2.2 vs. 32.7 +/- 2.4 ng/mg, p less than 0.001, respectively). Right ventricular weight increased in proportion to infarct size, and both were correlated with plasma immunoreactive atrial natriuretic peptide levels (r = 0.825, p less than 0.001 and r = 0.816, p less than 0.001, respectively). Right atrial immunoreactive atrial natriuretic peptide content was significantly higher than left in both controls and rats with infarction. Both right and left atrial immunoreactive atrial natriuretic peptide concentrations were negatively correlated with both right ventricular weight as well as plasma immunoreactive atrial natriuretic peptide concentrations (right atrium: r = -0.816, p less than 0.001, r = -0.708, p less than 0.01; left atrium: r = -0.687, p less than 0.01, r = -0.644, p less than 0.01, respectively). These results suggest that chronic stimulation of atrial natriuretic peptide release from both atria is associated with increased turnover and depleted stores of atrial natriuretic peptide in atria in proportion to the severity of heart failure. It also suggests that plasma atrial natriuretic peptide levels may be used as a reliable index of cardiac decompensation in chronic heart failure.

Animals↗
PubMed1994

Role of thallium-201 and PET imaging in evaluation of myocardial viability and management of patients with coronary artery disease and left ventricular dysfunction.

The reported mortality of patients with coronary artery disease (CAD) and congestive heart failure is high but variable. In the clinical management of these patients, the available treatment choices are medical therapy, cardiac transplantation and myocardial revascularization. Myocardial revascularization has become an attractive alternative in the management of patients with CAD and poor left ventricular function because medical therapy is associated with a high mortality and cardiac transplantation is expensive and not practical due to shortage of donor hearts. Myocardial revascularization, however, should be recommended in those patients in whom the procedure is very likely to reverse regional and global left ventricular dysfunction and to improve heart failure symptoms and survival. Thallium-201 rest-redistribution myocardial scintigraphy and PET imaging of myocardial perfusion and 18F-fluoro-deoxyglucose metabolism have been extensively evaluated for the assessment of myocardial viability and for prediction of recovery of regional left ventricular dysfunction following myocardial revascularization; with positive and negative predictive accuracies of 72% and 70% for 201Tl rest-redistribution imaging and 83% and 84% for perfusion-metabolism PET imaging. Both modalities also are predictive of improvement in left ventricular ejection fraction after myocardial revascularization. Patients with congestive heart failure who demonstrate the PET pattern of mismatch are more likely to improve their heart failure symptoms following revascularization than those without the mismatch pattern. Furthermore, the PET pattern of mismatch identifies a subgroup of patients who are at very high risk for cardiac death on medical therapy. Survival of these patients can be significantly improved by myocardial revascularization.

Coronary Artery Bypass↗
PubMed1990

Improvement of left ventricular contractility and relaxation with the beta 1-adrenergic receptor partial agonist xamoterol at rest and during exercise in patients with postinfarction left ventricular dysfunction. A placebo-controlled randomized trial.

A new cardioselective beta 1-adrenergic receptor agonist xamoterol (Corwin) has been developed for the treatment of heart failure. To study the acute hemodynamic effects of xamoterol, 24 patients, 39-70 years old, with mild-to-moderate postinfarction left ventricular dysfunction entered a double-blind, between-patient comparison of a single 5-minute intravenous infusion of xamoterol (0.2 mg/kg) and placebo. The acute hemodynamic effects of xamoterol were measured at rest and during two multistaged symptom-limited supine bicycle exercise tests (Ex-T), a control Ex-T followed by an Ex-T with either xamoterol or placebo. Compared with placebo, xamoterol significantly increased left ventricular contractility (Vmax and positive [+] dP/dt) and enhanced relaxation (dP/dt- and time constant relaxation) at rest and at the 25% and 50% levels of maximum exercise. The heart rate, the frequency and time to onset of anginal symptoms, the magnitude of exercise-induced ST segment depression, the left ventricular end-diastolic and peak systolic pressures, the mean pulmonary artery pressures, the cardiac index, the left ventricular stroke-work index, and the epinephrine and norepinephrine plasma levels at rest and during exercise did not differ significantly between placebo xamoterol groups. Thus, xamoterol can be a useful addition for the treatment of left ventricular dysfunction because of long-term ischemic heart disease.

Adrenergic beta-Agonists↗
PubMed1999

Does acute volume overloading in the setting of left ventricular dysfunction and pulmonary hypertension affect the defibrillation threshold?

The impact of acute volume overload hemodynamics on the DFT with concurrent moderate left ventricular systolic dysfunction is unknown. Ten mongrel dogs (17.2 kg), using a crossover study design, each had baseline (study 1) hemodynamic, echocardiographic, and DFT measurements. These measurements were repeated after left ventricular dysfunction was induced using a norepinephrine (5 micrograms/kg per min) infusion (study 2). Hemodynamic and DFT parameters were obtained simulating acute heart failure by volume overload with an 0.9% normal saline infusion to an associated mean pulmonary capillary wedge pressure of > 19 mmHg (study 3). Numerous significant echocardiographic and hemodynamic parameters were noted when the animals from studies 1 and 2, 2 and 3, and 1 and 3 were compared. A significant difference in the DFT was observed only when study animals 1 and 3 were compared (P < 0.02). None of the dogs were hypoxemic at the time of the acute heart failure DFT. The mechanism of this finding remains unknown. This data would suggest that acute volume overload with associated left ventricular dysfunction does adversely affect the DFT in a canine model.

Acute Disease↗
PubMed1987

[Mid-term outcome of acute right ventricular dysfunction in biventricular myocardial infarction. Hemodynamic and cineangiographic studies].

This study was designed to evaluate the mid-term outcome of the right ventricular (RV) dysfunction which characterizes infarction of both ventricles in the acute phase. Thirteen patients hospitalized for inaugural posterior or infero-posterior infarction extending to the right ventricle (haemodynamic and cineangiographic diagnosis) were explored in the acute phase and 4 months later by right heart catheterization and selective cineangiography of the right ventricle in a 30 degrees RAO projection. The results were compared with those obtained in a control group. Haemodynamically, the RV filling pressures (p less than 0.001) and the indices of RV dysfunction--i.e. RV end-diastolic pressure/RV systolic pressure ratio (p less than 0.001) and right atrial pressure/pulmonary wedge pressure ratio (p less than 0.02)--were significantly decreased between the acute and chronic phases, but they remained pathological compared with those measured in the control group. Angiographically, the right ventricular dysfunction in the acute phase was reflected in an increase of the RV end-systolic volume (p less than 0.02) and a decrease of the RV ejection fraction (p less than 0.01), whereas diastolic cavitary dilatation was inconstant, with mean values of RV end-diastolic volume close to those found in the control group. The systolic dysfunction persisted, unchanged, during the chronic phase. Segmental kinetics of the inferior wall was much reduced in the acute phase (p less than 0.001), this hypokinesia partially regressing in the chronic phase; but in fact there were wide individual variations, and some patients even recovered an almost normal contractility. Tricuspid valve regurgitation was frequent (6/13 cases) in the acute phase and regressed in 2 out of 3 cases in the chronic phase; its presence introduced a degree of bias in the measurement of RV end-systolic volume and RV ejection fraction, with a tendency to underestimate the severity of diastolic dysfunction. To summarize, right ventricular dysfunction was constant but often modest in the acute phase and remained relatively stable at mid-term, whereas segmental kinetics of the inferior wall improved, sometimes dramatically.

Adult↗