Effects of revascularisation and contractile reserve on left ventricular remodelling in patients with impaired left ventricular function

Objective: We sought to define the influence of revascularisation and contractile reserve on left ventricular (LV) remodelling in patients with LV dysfunction after myocardial infarction. Revascularisation of viable myocardium is associated with improved regional function, but the effect on remodelling is undefined. Methods: We studied 70 patients with coronary artery disease and LV dysfunction, 31 of whom underwent revascularisation. A standard dobutamine stress echocardiogram (DbE) was carried out. All patients underwent standard medical treatment; the decision to revascularise was made clinically, independent of this study. LV volumes and ejection fraction were measured by 3D echocardiography at baseline and after an average of 40 weeks. Results: There was no significant difference in baseline ejection fraction or volumes between patients who underwent revascularisation and the remainder. Compared to medically treated patients, revascularised patients had significant improvements in ejection fraction and end-systolic volume in follow-up. The impact of baseline variables on remodelling was assessed by dividing patients into tertiles of LV ejection fraction and volumes. Revascularised patients in the lowest tertile of ejection fraction at baseline (<38%) had a significant improvement in end-systolic volume and ejection fraction, larger than obtained in medically treated patients with low ejection fraction. Revascularised patients with an ejection fraction >38% did not show significant improvement in volumes compared to baseline. Revascularised patients in the largest tertiles of end-systolic (>88 ml) or end-diastolic volume (>149 ml) at baseline had a significant improvement in end-systolic volume. Conclusion: Remodeling appears to occur independent of the presence of regional contractile reserve but does correlate with the volume response to low-dose dobutamine. (C) 2003 Elsevier Ireland Ltd. All rights reserved.

Use of tissue Doppler imaging to facilitate the prediction of events in patients with abnormal left ventricular function dobutamine echocardiography

The extent of abnormality in patients with positive do-butamine echocardiography (DE) is predictive of risk, but the wall motion score (WMS) has low concordance among observers. We sought whether quantifying the extent of abnormal wall motion using tissue Doppler (TD) could guide risk assessment in patients with abnormal DE in 576 patients with known or suspected coronary artery disease; standard DE was combined with color TD imaging at peak dose. WMS was assessed by an expert observer and studies were identified as abnormal in the presence of 2:1 segments with resting or stress-induced wall motion abnormalities. Patients with abnormal DE had peak systolic velocity measured in each segment. Tissue tracking was used to measure myocardial displacement. Follow-up for death or infarction was per-formed after. 16 +/- 12 months. Of 251 patients with abnormal DE, 22 patients died (20 from cardiac causes) and 7 had nonfatal myocardial infarctionis. The average WMS in patients with events was 1.8 +/- 0.5, compared with 1.7 +/- 0.5 in patients without events (p = NS). The average systolic velocity in patients with events was 4.9 +/- 1.7 cm/s and 6.4 +/- 6.5 cm/s in the patients without events (p <0.001). The average tissue tracking in patients with events was 4.5 +/- 1.5 mm and was significant. (5.7 +/- 3.1 mm),in those,without events (p <0.001). Thus, TD is an alternative to WMS for quantifying the total extent of abnormal left ventricular function-at DE, and appears to be superior for predicting adverse outcomes. (C) 2004 by Excerpta Medica, Inc.

Eosinophilic heart: Marked left ventricular wall thickening and myocardial dysfunction improving with corticosteroid therapy

We report a case of a 34-year-old male with acute severe heart failure associated with marked concentric left ventricular wall thickening and biopsy evidence of eosinophilic myocardial infiltrate. This appears to be an unusual description of this degree of concentric myocardial thickening in eosinophilic myocarditis coupled with Doppler tissue echocardiography. Following high-dose corticosteroid treatment, wall thickness, systolic and diastolic left ventricular function normalized and the patient experienced a dramatic clinical improvement. (ECHOCARDIOGRAPHY, Volume 20, May 2003).

Achieving better in-hospital and after-hospital care of patients with acute cardiac disease

In patients hospitalised with acute coronary syndromes (ACS) and congestive heart failure (CHF), evidence suggests opportunities for improving in-hospital and after hospital care, patient self-care, and hospital-community integration. A multidisciplinary quality improvement program was designed and instigated in Brisbane in October 2000 involving 250 clinicians at three teaching hospitals, 1080 general practitioners (GPs) from five Divisions of General Practice, 1594 patients with ACS and 904 patients with CHF. Quality improvement interventions were implemented over 17 months after a 6-month baseline period and included: clinical decision support (clinical practice guidelines, reminders, checklists, clinical pathways); educational interventions (seminars, academic detailing); regular performance feedback; patient self-management strategies; and hospital-community integration (discharge referral summaries; community pharmacist liaison; patient prompts to attend GPs). Using a before-after study design to assess program impact, significantly more program patients compared with historical controls received: ACS: Angiotensin-converting enzyme (ACE) inhibitors and lipid-lowering agents at discharge, aspirin and beta-blockers at 3 months after discharge, inpatient cardiac counselling, and referral to outpatient cardiac rehabilitation. CHF. Assessment for reversible precipitants, use of prophylaxis for deep-venous thrombosis, beta-blockers at discharge, ACE inhibitors at 6 months after discharge, imaging of left ventricular function, and optimal management of blood pressure levels. Risk-adjusted mortality rates at 6 and 12 months decreased, respectively, from 9.8% to 7.4% (P=0.06) and from 13.4% to 10.1% (P= 0.06) for patients with ACS and from 22.8% to 15.2% (P < 0.001) and from 32.8% to 22.4% (P= 0.005) for patients with CHF. Quality improvement programs that feature multifaceted interventions across the continuum of care can change clinical culture, optimise care and improve clinical outcomes.

Diabetic cardiomyopathy: Evidence, mechanisms, and therapeutic implications

The presence of a diabetic cardiomyopathy, independent of hypertension and coronary artery disease, is still controversial. This systematic review seeks to evaluate the evidence for the existence of this condition, to clarify the possible mechanisms responsible, and to consider possible therapeutic implications. The existence of a diabetic cardiomyopathy is supported by epidemiological findings showing the association of diabetes with heart failure; clinical studies confirming the association of diabetes with left ventricular dysfunction independent of hypertension, coronary artery disease, and other heart disease; and experimental evidence of myocardial structural and functional changes. The most important mechanisms of diabetic cardiomyopathy are metabolic disturbances (depletion of glucose transporter 4, increased free fatty acids, carnitine deficiency, changes in calcium homeostasis), myocardial fibrosis (association with increases in angiotensin II, IGF-I, and inflammatory cytokines), small vessel disease (microangiopathy, impaired coronary flow reserve, and endothelial dysfunction), cardiac autonomic neuropathy (denervation and alterations in myocardial catecholamine levels), and insulin resistance (hyperinsulinemia and reduced insulin sensitivity). This review presents evidence that diabetes is associated with a cardiomyopathy, independent of comorbid conditions, and that metabolic disturbances, myocardial fibrosis, small vessel disease, cardiac autonomic neuropathy, and insulin resistance may all contribute to the development of diabetic heart disease.

Is quantitative interpretation likely to increase sensitivity of dobutamine stress echocardiography? A study of false-negative results

Background: False-negative interpretations of do-butamine stress echocardiography (DSE) may be associated with reduced wall stress. using measurements of contraction, we sought whether these segments were actually ischemic but unrecognized or showed normal contraction. Methods. We studied 48 patients (29 men; mean age 60 +/- 10 years) with normal regional function on the basis of standard qualitative interpretation of DSE. At coronary angiography within. 6 months of DSE, 32 were identified as having true-negative and 16 as having false-negative results of DSE. Three apical views were used to measure regional function with color Doppler tissue, integrated backscatter, and strain rate imaging. Cyclic variation of integrated backscatter was measured in 16 segments, and strain rate and peak systolic strain was calculated in 6 walls at rest and peak stress. Results. Segments with false-negative results of DSE were divided into 2 groups with and without low wall stress according to previously published cut-off values. Age, sex, left ventricular mass, left ventricular geometric pattern, and peak workload were not significantly different between patients with true and false-negative results of DSE. Importantly, no significant differences in cyclic variation and strain parameters at rest and peak stress were found among segments with true-and false-negative results of DSE with and without low wall stress. Stenosis severity had no influence on cyclic variation and strain parameters at peak stress. Conclusions: False-negative results of DSE reflect lack of ischemia rather than underinterpretation of regional left ventricular function. Quantitative markers are unlikely to increase the sensitivity of DSE.

Postsystolic thickening detected by Doppler myocardial imaging: A marker of viability or ischemia in patients with myocardial infarction

Background: Postsystolic thickening (PST) of ischemic myocardial segments has been reported to account for the characteristic heterogeneity or regional asynchrony of myocardial wall motion during acute ischemia. Hypothesis: Postsystolic thickening detected by Doppler myocardial imaging (DMI) could be a useful clinical index of myocardial viability or peri-infarction viability in patients with myocardial infarction (MI). Methods: Doppler myocardial imaging was recorded at each stage of a standard dobutamine stress echocardiogram (DSE) in 20 patients (16 male, 60 +/- 13 years) with an NIT in the territory of the left anterior descending artery. Myocardial velocity data were measured in the interventricular septum and apical inferior segment of the MI territory. Postsystolic thickening was identified if the absolute velocity of PST was higher than peak systolic velocity in the presence of either a resting PST > 2.0 cm/s or if PST doubled at low-dose dobutamine infusion. Results: Doppler myocardial imaging data could be analyzed in 38 ischemic segments (95%), and PST was observed in 21 segments (55%), including 3 segments showing PST only at low-dose dobutamine infusion. There was no significant difference of baseline wall motion score index (2.1 +/- 0.3 vs. 2.1 +/- 0.6, p = 0.77) or peak systolic velocity (1.1 +/- 1.1 vs. 1.9 +/- 2.0 cm/s, p = 0.05) between segments with and without PST Peri-infarction ischemia or viability during DSE was more frequently observed in segments with PST than in those without (86 vs. 24%, p < 0.05). The sensitivity and specificity of PST for prediction of peri-infarction viability or ischemia was 82 and 81%, respectively. Conclusions: Postsystolic thickening in the infarct territory detected by DMI is closely related with peri-infarction ischemia or viability at DSE.

Should we be evaluating the ventricle or the myocardium? Advances in tissue characterization

The assessment of left ventricular (LV) dysfunction has become the most frequent indication for echocardiography, a growth that has been driven by the epidemic of heart failure. The value of echocardiography for assessing LV dysfunction is unquestionable, the quantification of both LV systolic and diastolic dysfunction being a reliable indicator of mortality. 1,2 Nonetheless, whereas the ejection fraction and diastolic assessment are important clinical parameters, they are highly dependent on loading and may produce abnormal results under unusual loading conditions. Moreover, in a number of situations where the LV is evaluated, although the overall function is an important finding, the referring clinician is really requesting an assessment of the nature of the underlying myocardial tissue (Table 1). Indeed, in some situations (eg, among family members of patients with a cardiomyopathy) questions arise about the presence of pathology despite the presence of normal ventricular function. Traditionally, it has been difficult to obtain this information because of the lack of sufficiently sensitive parameters, but a number of new developments have shown such success in this area that the clinical application of tools to assess the myocardium in routine practice appears finally to be a realistic proposition.