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PubMed2003

Central sleep apnea in left ventricular dysfunction: prevalence and implications for arrhythmic risk.

BACKGROUND: The prevalence and characteristics of sleep-disordered breathing in patients with asymptomatic left ventricular (LV) dysfunction are unknown. Therefore, we evaluated the prevalence of sleep-disordered breathing in patients with LV dysfunction without overt heart failure and tested the hypothesis that sleep-disordered breathing is linked to greater hemodynamic and autonomic impairment. METHODS AND RESULTS: We studied 47 patients with LV ejection fractions or=15/h, was present in 26 patients (55%), 17 (36%) of whom had severe CSA (apnea-hypopnea index >or=30/h). Obstructive sleep apnea was evident in 5 patients (11%). The prevalence and severity of CSA were higher in patients with ischemic cardiomyopathy than in patients with nonischemic cardiomyopathy (P<0.05). Exercise tolerance and echocardiographic indices of systolic and diastolic function were similar in patients without CSA, with mild CSA, and with severe CSA. Heart rate variability was markedly depressed in patients with CSA (P<0.05). Patients with severe CSA also had a higher incidence of nonsustained ventricular tachycardia (P=0.05). CONCLUSIONS: CSA is highly prevalent in patients with asymptomatic LV dysfunction. The severity of CSA may not be related to the severity of hemodynamic impairment. Severe CSA is associated with impaired cardiac autonomic control and with increased cardiac arrhythmias.

Arrhythmias, Cardiac↗
PubMed2000

The effects of beta(1)-blockade on oxidative metabolism and the metabolic cost of ventricular work in patients with left ventricular dysfunction: A double-blind, placebo-controlled, positron-emission tomography study.

BACKGROUND: The mechanism for the beneficial effect of beta-blocker therapy in patients with left ventricular (LV) dysfunction is unclear, but it may relate to an energy-sparing effect that results in improved cardiac efficiency. C-11 acetate kinetics, measured using positron-emission tomography (PET), are a proven noninvasive marker of oxidative metabolism and myocardial oxygen consumption (MVO(2)). This approach can be used to measure the work-metabolic index, which is a noninvasive estimate of cardiac efficiency. METHODS AND RESULTS: The aim of this study was to determine the effect of metoprolol on oxidative metabolism and the work-metabolic index in patients with LV dysfunction. Forty patients (29 with ischemic and 11 with nonischemic heart disease; LV ejection fraction <40%) were randomized to receive metoprolol or placebo in a treatment protocol of titration plus 3 months of stable therapy. Seven patients were not included in analysis because of withdrawal from the study, incomplete follow-up, or nonanalyzable PET data. The rate of oxidative metabolism (k) was measured using C-11-acetate PET, and stoke volume index (SVI) was measured using echocardiography. The work-metabolic index was calculated as follows: (systolic blood pressure x SVI x heart rate)/k. No significant change in oxidative metabolism occurred with placebo (k=0.061+/-0.022 to 0.054+/-0.012 per minute). Metoprolol reduced oxidative metabolism (k=0.062+/-0. 024 to 0.045+/-0.015 per minute; P:=0.002). The work-metabolic index did not change with placebo (from 5.29+/-2.46 x 10(6) to 5.14+/-2. 06 x 10(6) mm Hg. mL/m(2)), but it increased with metoprolol (from 5. 31+/-2.15 x 10(6) to 7.08+/-2.36 x 10(6) mm Hg. mL/m(2); P:<0.001). CONCLUSIONS: Selective beta-blocker therapy with metoprolol leads to a reduction in oxidative metabolism and an improvement in cardiac efficiency in patients with LV dysfunction. It is likely that this energy-sparing effect contributes to the clinical benefits observed with beta-blocker therapy in this patient population.

Acetates↗
PubMed2001

Impairment of myocardial blood flow reserve in patients with asymptomatic left ventricular dysfunction: effects of ACE-inhibition with perindopril.

Myocardial blood flow (MBF) reserve is impaired in patients with symptomatic chronic heart failure. Whether this is already present in asymptomatic left ventricular (LV) dysfunction, and whether it is affected by angiotensin converting enzyme (ACE) inhibition, is unknown. We examined MBF in 20 patients with asymptomatic LV dysfunction and compared them to healthy volunteers. MBF (reserve) was assessed with positron emission tomography (PET) and N-13 ammonia at rest, during dipyridamole stress test (DST) and during cold pressor test (CPT). Further, in the LV-dysfunction group, we studied the effects of 3 months treatment with ACE inhibition with a second PET study. Patients were randomized double-blind to perindopril 4 mg daily or placebo. MBF at rest was similar in controls and patients. DST-induced MBF reserve, however, was decreased in patients vs. controls (1.71+/-0.2 vs. 2.62+/-0.5, respectively p < 0.05). Also CPT-induced MBF was lower in patients (1.14+/-0.06 vs. 1.23+/-0.03, p < 0.05). After 3 months double-blind treatment, CPT-induced MBF decreased in the placebo group (from 1.12+/-0.02 to 0.93+/-0.06), but was preserved in the perindopril group (from 1.16+/-0.08 to 1.14+/-0.08 shifts from baseline: -0.19+/-0.05 vs. -0.02+/-0.07 respectively p = 0.07). This was compatible with a trend to a smaller increase in coronary vascular resistance during CPT (1.23+/-0.08 vs. 1.03+/-0.06, placebo vs. perindopril, p = 0.06). In patients with asymptomatic LV dysfunction, MBF, both after vasodilation and after CPT, is already impaired. ACE inhibition with perindopril during this short-term treatment had no significant effects.

Adult↗
PubMed2001

Mechanism of ischemic mitral regurgitation with segmental left ventricular dysfunction: three-dimensional echocardiographic studies in models of acute and chronic progressive regurgitation.

OBJECTIVES: This study aimed to separate proposed mechanisms for segmental ischemic mitral regurgitation (MR), including left ventricular (LV) dysfunction versus geometric distortion by LV dilation, using models of acute and chronic segmental ischemic LV dysfunction evaluated by three-dimensional (3D) echocardiography. BACKGROUND: Dysfunction and dilation-both mechanisms with practical therapeutic implications-are difficult to separate in patients. METHODS: In seven dogs with acute left circumflex (LCX) coronary ligation, LV expansion was initially restricted and then permitted to occur. In seven sheep with LCX branch ligation, LV expansion was also initially limited but became prominent with remodeling over eight weeks. Three-dimensional echo reconstruction quantified mitral apparatus geometry and MR volume. RESULTS: In the acute model, despite LV dysfunction with ejection fraction = 23 +/- 8%, MR was initially trace with limited LV dilation, but it became moderate with subsequent prominent dilation. In the chronic model, MR was also initially trace, but it became moderate over eight weeks as the LV dilated and changed shape. In both models, the only independent predictor of MR volume was increased tethering distance from the papillary muscles (PMs) to the anterior annulus, especially medial and posterior shift of the ischemic medial PM, measured by 3D reconstruction (r2 = 0.75 and 0.86, respectively). Mitral regurgitation volume did not correlate with LV ejection fraction or dP/dt. CONCLUSIONS: Segmental ischemic LV contractile dysfunction without dilation, even in the PM territory, fails to produce important MR. The development of MR relates strongly to changes in the 3D geometry of the mitral apparatus, with implications for approaches to restore a more favorable configuration.

Animals↗
PubMed2002

Long-term prognostic value of stress-redistribution-reinjection Tl-201 imaging in patients with severe left ventricular dysfunction and coronary artery bypass surgery.

OBJECTIVES: This study sought to evaluate the long-term prognostic significance of stress-redistribution-reinjection Tl-201 imaging in patients with severe left ventricular (LV) dysfunction and coronary artery bypass surgery. BACKGROUND: Preoperative stress-redistribution-reinjection Tl-201 imaging detects viable but asynergic segments which show functional improvement postoperatively and is considered as a valuable noninvasive method in selection of patients with severe LV dysfunction for revascularization. The long-term prognostic value of the reinjection technique remains unclear. METHODS: Fifty-two patients with severe LV dysfunction (mean ejection fraction (EF) 0.32+/-0.03) who underwent coronary artery bypass surgery in 1993-1994 were included in the study. Patients had follow-up 49+/-12 months. LV function was assessed by two-dimensional echocardiography. Perfusion was assessed by Tl-201 SPECT imaging and was graded on a four-point scale (0 = normal, 3 = absent uptake) using the 20 segment model. Perfusion index was derived by adding the score of all segments and dividing these by 20. Patients were divided into two groups. Group A comprised patients with seven and more dysfunctional viable myocardial segments. Group B included patients with less than seven dysfunctional but viable segments. RESULTS: Mean EF increased from 0.32+/-0.03 to 0.46+/-0.04. Mean perfusion index did not show a significant difference as a whole during follow-up compared to the early postoperative values (0.9+/-0.4 and 1.1+/-0.4, p = NS). When adequacy of revascularization was considered, the predictive value of a positive preoperative viability test for functional improvement was 82%. Nineteen cardiac events occurred in group B patients and six in group A patients: six deaths (four from cardiac and two from noncardiac causes), 13 myocardial infarctions (MI). Multivariate Cox survival analysis identified the number of viable segments detected preoperatively (chi2 = 7.2, p = 0.002), postoperative improvement in Tl-uptake (chi2 = 6.6, p = 0.01) and functional improvement (chi2 = 5.3, p = 0.03) postoperatively as independent predictors of cardiac events. Preoperative EF and functional capacity were not associated with cardiac events in long-term prognosis. CONCLUSION: These data suggest that preoperative stress-redistribution-reinjection Tl-201 imaging, specifically the number of viable segments detected preoperatively and postoperative improvement in Tl-201 uptake provide important long-term prognostic information in patients with severe LV dysfunction who had coronary artery bypass surgery.

Case-Control Studies↗
PubMed2000

Effects of metoprolol CR in patients with ischemic and dilated cardiomyopathy : the randomized evaluation of strategies for left ventricular dysfunction pilot study.

BACKGROUND: Metoprolol provides clinical benefits in patients with congestive heart failure (CHF). In this study, we investigated the effects of controlled-release metoprolol (metoprolol CR) on clinical status, on left ventricular (LV) volumes and function, and on neurohumoral activation in a large number of patients with CHF of mixed causes. METHODS AND RESULTS: Four hundred twenty-six patients with symptomatic CHF were randomized to receive metoprolol CR or placebo for 24 weeks. Metoprolol CR did not affect 6-minute walk distance, New York Heart Association functional class, or quality of life. However, there was a significant improvement in measures of LV function with an attenuation in the increase in LV end-diastolic (+23+/-65 mL [placebo] versus +6+/-61 mL, P=0.01) and LV end-systolic (+19+/-55 mL [placebo] versus -2+/-51 mL, P<0.001) volumes after 24 weeks of therapy. LV ejection fraction was unchanged (-0.05% or -0.005) in the placebo group but increased by 2. 4% in the metoprolol CR-treated patients (P=0.001). Patients receiving metoprolol CR had a greater decrease in angiotensin II (P=0.036) and renin (P=0.032) levels but an increase in N-terminal atrial natriuretic peptide and brain natriuretic peptide levels (P<0. 01). There were fewer deaths in the group receiving beta-blockers (3. 4% versus 8.1%), and there was a similar number of patients experiencing the composite outcomes of death or any hospitalization. CONCLUSIONS: When added to ACE inhibitors, angiotensin II receptor antagonists, or both, the use of metoprolol CR improves ventricular function, reduces activation of the renin-angiotensin systems, and results in fewer deaths.

Adrenergic beta-Antagonists↗
PubMed1993

Prevalence and incidence of left ventricular dysfunction in patients with human immunodeficiency virus infection.

The prevalence and incidence of left ventricular (LV) dysfunction was examined in patients infected with the human immunodeficiency virus (HIV). Sixty-nine randomly selected patients diagnosed with HIV infection who were followed in HIV clinics were prospectively evaluated by 2-dimensional echocardiography. Mean follow-up duration was 11 months. Additionally, 39 consecutive HIV-infected patients referred to the Cardiomyopathy Service and found to have LV dysfunction by 2-dimensional echocardiography were also studied. Of the 39 referred patients, 34 (87%) were referred for recent onset, unexplained, congestive heart failure. During this time, the HIV clinic population comprised 1,819 alive and actively followed patients; the 39 cardiomyopathy referrals therefore constituted a crude rate of 2.1% for this population. Of the 69 prospectively studied patients without clinical heart disease, a 14.5% prevalence of global LV hypokinesia and an incidence of 18%/patient-year were found. During a maximal 18-month follow-up period, 4 prospective patients (5.8%) developed symptoms of congestive heart failure. A greater proportion of prospective and referred patients with LV dysfunction had CD4 counts < 100/mm3 (62 and 79%, respectively) than did that of those without LV dysfunction (35%). In conclusion, the high rate of unexpected LV dysfunction in this HIV-infected population suggests that early cardiac contractile abnormalities may involve a significant number of patients, most of whom have low CD4 counts. A subgroup of these patients appears to progress to symptomatic congestive heart failure.

Adult↗
PubMed2006

Effect of combination therapy with simvastatin and carvedilol in patients with left ventricular dysfunction complicated with acute myocardial infarction who underwent percutaneous coronary intervention.

BACKGROUND: This study assessed the effects of combination therapy with simvastatin and carvedilol on clinical outcome in patients with left ventricular (LV) dysfunction after acute myocardial infarction (AMI). METHODS AND RESULTS: The study retrospectively analyzed the data from 672 patients with LV dysfunction [LV ejection fraction (LVEF) <40%] complicated with AMI who underwent percutaneous coronary intervention (PCI). The patients were divided into 4 treatment groups: combination group (n=160), simvastatin only group (n=216), carvedilol only group (n=242), neither treatment group (n=54). At 6 months after PCI, the LVEF had improved most significantly in the combination group. During 1-year follow-up, cardiac death occurred most frequently in the neither treatment group compared with the other 3 groups (combination: 4%, simvastatin alone: 7%, carvedilol alone: 8%, neither: 17%, p<0.001 between neither treatment and other 3 groups). The results on major adverse cardiovascular events (MACE) showed that the combination of simvastatin and carvedilol was associated with a relative risk reduction of 53% (p<0.001), treatment with simvastatin alone with a relative risk reduction of 44% (p=0.001), and carvedilol alone with a relative risk reduction of 40% (p=0.003) compared with neither treatment. The independent predictors of 1-year MACE were neither treatment, elevated high sensitivity C-reactive protein (> or =0.5 mg/dl), and old age (>70 years). CONCLUSION: Combination therapy with simvastatin and carvedilol had a positive impact on the endpoints of cardiovascular death and MACE and seems to have an additive beneficial effect on these endpoints in patients with LV dysfunction complicated with AMI who underwent PCI.

Aged↗
PubMed2006

Cost-effectiveness of eplerenone in patients with left ventricular dysfunction after myocardial infarction--an analysis of the EPHESUS study from a Swiss perspective.

OBJECTIVE: The EPHESUS study demonstrated that aldosterone blockade with eplerenone decreased mortality in patients with left ventricular systolic dysfunction (LVSD) and heart failure after acute myocardial infarction (AMI). The EPHESUS pharmacoeconomic analysis was performed to evaluate the cost-effectiveness of eplerenone in the Swiss setting. MATERIALS AND METHODS: A total of 6,632 patients with LVSD and heart failure after AMI were randomized to eplerenone or placebo and followed for a mean of 16 months. The co-primary endpoints were all-cause death and the composite of cardiovascular death/cardiovascular hospitalization. The evaluation of resource use included hospitalizations, outpatient services, and medications. Survival beyond the trial period was estimated using data from the Framingham Heart Study, the Saskatchewan Health database, and the Worcester Heart Attack Registry. The incremental cost-effectiveness of eplerenone in cost per life-year and quality-adjusted life-year gained was estimated. The perspective of the Swiss third party payers was used. Daily treatment costs of eplerenone were set at CHF 3.88. All other resources were valued on the basis of official tariffs. Discounting of the results was performed at a rate of 3%. RESULTS: The number of life-years gained with eplerenone was 0.1083 based on Framingham, 0.0661 with Saskatchewan and 0.1518 with Worcester survival estimates. Total costs were CHF 1,028 higher over the trial period in the eplerenone arm, due to drug cost. The incremental cost-effectiveness ratio was CHF 10,145 per life-year gained with Framingham, CHF 16,178 with Saskatchewan, and CHF 7,693 with Worcester survival estimates. The corresponding costs per QALY were CHF 15,219, CHF 23,965 and CHF 11,337, respectively. CONCLUSION: Eplerenone is effective in reducing mortality and, in Switzerland, is also cost-effective in increasing years of life for patients with LVSD after AMI.

Adult↗
PubMed2005

Two-year clinical outcomes after enhanced external counterpulsation (EECP) therapy in patients with refractory angina pectoris and left ventricular dysfunction (report from The International EECP Patient Registry).

Enhanced external counterpulsation (EECP) is a noninvasive circulatory assist device that has recently emerged as a treatment option for refractory angina in left ventricular (LV) dysfunction. This 2-year cohort study describes the long-term follow-up of patients who had severe LV dysfunction that was treated with EECP for angina pectoris and reports clinical outcomes, event-free survival rates, and the incidence of repeat EECP. This study included 363 patients who had refractory angina and LV ejection fraction < or =35%. Most patients reported quality of life as poor. After completion of treatment, there was a significant decrease in severity of angina class (p < 0.001), and 72% improved from severe angina to no angina or mild angina. Fifty-two percent of patients discontinued nitroglycerin use. Quality of life improved substantially. At 2 years this decrease in angina was maintained in 55% of patients. The 2-year survival rate was 83%, and the major adverse cardiovascular event-free survival rate was 70%. Forty-three percent had no reported cardiac hospitalization; 81% had no reported congestive heart failure events. Repeat EECP was performed in 20% of these patients. The only significant independent predictor of repeat EECP in a proportional hazard model was failure to complete the first EECP treatment course (hazard ratio 2.9, 95% confidence interval 1.7 to 4.9). Improvements in angina symptoms and quality of life were maintained at 2 years. In conclusion, for patients who have high-risk LV dysfunction, EECP offers an effective, durable therapeutic approach for refractory angina. Decreased angina and improvement in quality of life were maintained at 2 years, with modest repeat EECP and low major cardiovascular event rates.

Aged↗
PubMed2004

Alterations in myofilament function contribute to left ventricular dysfunction in pigs early after myocardial infarction.

Myocardial infarction (MI) initiates cardiac remodeling, depresses pump function, and predisposes to heart failure. This study was designed to identify early alterations in Ca2+ handling and myofilament proteins, which may contribute to contractile dysfunction and reduced beta-adrenergic responsiveness in postinfarct remodeled myocardium. Protein composition and contractile function of skinned cardiomyocytes were studied in remote, noninfarcted left ventricular (LV) subendocardium from pigs 3 weeks after MI caused by permanent left circumflex artery (LCx) ligation and in sham-operated pigs. LCx ligation induced a 19% increase in LV weight, a 69% increase in LV end-diastolic area, and a decrease in ejection fraction from 54+/-5% to 35+/-4% (all P<0.05), whereas cardiac responsiveness to exercise-induced increases in circulating noradrenaline levels was blunted. Endogenous protein kinase A (PKA) was significantly reduced in remote myocardium of MI animals, and a negative correlation (R=0.62; P<0.05) was found between cAMP levels and LV weight-to-body weight ratio. Furthermore, SERCA2a expression was 23% lower after MI compared with sham. Maximal isometric force generated by isolated skinned myocytes was significantly lower after MI than in sham (15.4+/-1.5 versus 19.2+/-0.9 kN/m2; P<0.05), which might be attributable to a small degree of troponin I (TnI) degradation observed in remodeled postinfarct myocardium. An increase in Ca2+ sensitivity of force (pCa50) was observed after MI compared with sham (DeltapCa50=0.17), which was abolished by incubating myocytes with exogenous PKA, indicating that the increased Ca2+ sensitivity resulted from reduced TnI phosphorylation. In conclusion, remodeling of noninfarcted pig myocardium is associated with decreased SERCA2a and myofilament function, which may contribute to depressed LV function. The full text of this article is available online at http://circres.ahajournals.org.

Actin Cytoskeleton↗
PubMed2004

Direct epicardial mapping predicts the recovery of left ventricular dysfunction in chronic ischaemic myocardium.

AIMS: This study investigated the hypothesis that direct epicardial bipolar mapping is able to predict the recovery of left ventricular (LV) dysfunction in ischaemic myocardium. METHODS AND RESULTS: In 34 patients with CAD, a maximum of 102 bipolar epicardial electrograms per patient (n=3468 electrograms) were simultaneously recorded with a ventricular jacket array intraoperatively immediately prior to revascularization. Only LV electrograms with good myocardial contact (n=1813, 52+/-14 per patient, mean+/-SD) were analyzed. In accordance to the position of each electrode, segmental myocardial function was assessed by transthoracic echocardiography before and 7+/-2 months (mean+/-SD; range 3-10 months) after CABG using a wall motion score. Preoperatively dysfunctional segments (n=700) were classified as viable (improvement in wall motion score of at least 20% following CABG, n=424) or non-viable (no improvement, n=276). Bipolar voltage was significantly lower in non-viable when compared to viable myocardium (P<0.001, ANOVA) At a cut-off value of 5.9mV, ROC-curve analysis for bipolar voltage (to discriminate between viable and non-viable myocardium) revealed a sensitivity of 83% at a specificity of 83% (area under the ROC-curve of 0.92+/-0.01, mean+/-SE). CONCLUSIONS: Direct epicardial mapping is able to predict the recovery of chronically ischaemic dysfunctional myocardium and thereby proves the presence of myocardial viability.

Analysis of Variance↗
PubMed2005

Is glycated haemoglobin a sensitive index to identify left ventricular dysfunction two months after acute myocardial infarction in normotensive subjects?

BACKGROUND: Glycated haemoglobin concentration (HbA1c) is a marker of glucose metabolism. Glucose intolerance is associated with a high incidence of left ventricular (LV) dysfunction after acute myocardial infarction (AMI). This study was carried out in order to relate HbA1c to LV function two months following AMI in 171 normotensive patients who were not previously known to have had diabetes mellitus. METHODS: Oral glucose tolerance test (GTT) and HbA1c. Echo and Doppler-cardiography were used to measure the E/A (peak velocity of the early filling/atrial contraction waves) at rest and at peak isometric exercise (IME), deceleration time (DT) of E wave, LV ejection fraction (LVEF), LV mass index and diastolic LV function. RESULTS: GTT was diabetic in 20, impaired in 35 and normal in 116 subjects. HbA1c was >6.0% (cut off level for high risk subjects) in 76 patients (67%) with impaired relaxation (E/A<1) during IME and in 30 patients (27%) with restrictive LV filling (identified by E/A=1-2, DT<140 ms). The sensitivity and specificity of HbA1c to predict underlying impaired LV relaxation were 68% and 37%, respectively, and to predict restrictive LV filling were 27% and 98%, respectively. Whereas in univariate analysis, DT.3 was linearly related to HbA1c only (p=0.0002), multiple regression analysis showed that HbA1c was related to LVEF, DT and E/A but not to LVH, LVMI, smoking habit, age, gender and creatinine kinase level during admission for AMI. CONCLUSION: At 2 months after admission for AMI, HbA1c is related to systolic and diastolic LV function but not to LVMI or LVH. HbA1c is a sensitive predictor of impaired relaxation but highly specific to rule out underlying non-restrictive LV filling.

Acute Disease↗