Patterns of left ventricular dilation during the six months after myocardial infarction

Left ventricular remodelling after ST-segment elevation myocardial infarction: sex differences and prognosis

Aims

Left ventricular (LV) remodelling after ST‐segment elevation myocardial infarction (STEMI) worsens outcome. The effect of sex on LV post‐infarct remodelling is unknown. We therefore investigated the sex distribution and long‐term prognosis of LV post‐infarct remodelling after STEMI in the contemporary era of primary percutaneous coronary intervention (PCI) and optimal pharmacotherapy.

Methods and results

Data were obtained from an ongoing primary PCI STEMI registry. LV remodelling was defined as ≥20% increase in LV end‐diastolic volume at either 3, 6, or 12 months post‐infarct, and LV remodelling impact on outcome was evaluated with a log‐rank test. A total population of 1995 STEMI patients were analysed (mean age 60 ± 12 years): 1527 (77%) men and 468 (23%) women. The mean age of male patients was 60±11 versus 63±13 years for women (P < 0.001). A total of 953 (48%) patients experienced LV remodelling in the first 12 months of follow‐up, and it was equally frequent amongst men (n = 729, 48%) and women (n = 224, 48%). After a median follow‐up of 94 (interquartile range 69–119) months, 225 patients died: 171 (11%) men and 54 (12%) women. No survival difference was seen between remodellers and non‐remodellers in the male (P = 0.113) and female (P = 0.920) groups.

Conclusion

LV post‐infarct remodelling incidence, as well as long‐term survival of LV remodellers and non‐remodellers, was similar in men and women who were treated with primary PCI and optimal pharmacotherapy post‐STEMI.

Marine omega-3 highly unsaturated fatty acids: From mechanisms to clinical implications in heart failure and arrhythmias

Therapeutic implications of marine omega-3 highly unsaturated fatty acids (HUFA) in cardiovascular disease are still discussed controversially. Several clinical trials report divergent findings and thus leave ambiguity on the meaning of oral omega-3 therapy. Potential prognostic indications of HUFA treatment have been predominantly studied in coronary artery disease, sudden cardiac death, ventricular arrhythmias, atrial fibrillation and heart failure of various origin. It is suspected that increased ventricular wall stress is crucially involved in the prognosis of heart failure. Increased wall stress and an unfavorable myocardial remodeling is associated with an increased risk of arrhythmias by stretch-activated membrane ion channels. Integration of HUFA into the microenvironment of cardiomyocyte ion channels lead to allosteric changes and increase the electrical stability. Increased ventricular wall stress appears to be involved in the local myocardial as well as in the hepatic fatty acid metabolism, i.e. a cardio-hepatic syndrome. Influences of an altered endogenous HUFA metabolism and an inverse shift of the fatty acid profile was underrated in the past. A better understanding of these interacting endogenous mechanisms appears to be required for interpreting the findings of recent experimental and clinical studies. The present article critically reviews major studies on basic pathophysiological mechanisms and treatment effects in clinical trials.

An integrated electromechanical-growth heart model for simulating cardiac therapies

An emerging class of models has been developed in recent years to predict cardiac growth and remodeling (G&R). We recently developed a cardiac G&R constitutive model that predicts remodeling in response to elevated hemodynamics loading, and a subsequent reversal of the remodeling process when the loading is reduced. Here, we describe the integration of this G&R model to an existing strongly coupled electromechanical model of the heart. A separation of timescale between growth deformation and elastic deformation was invoked in this integrated electromechanical-growth heart model. To test our model, we applied the G&R scheme to simulate the effects of myocardial infarction in a realistic left ventricular (LV) geometry using the finite element method. We also simulate the effects of a novel therapy that is based on alteration of the infarct mechanical properties. We show that our proposed model is able to predict key features that are consistent with experiments. Specifically, we show that the presence of a non-contractile infarct leads to a dilation of the left ventricle that results in a rightward shift of the pressure volume loop. Our model also predicts that G&R is attenuated by a reduction in LV dilation when the infarct stiffness is increased.

Guidelines for translational research in heart failure

Heart failure (HF) remains a major cause of death and hospitalization worldwide. Despite medical advances, the prognosis of HF remains poor and new therapeutic approaches are urgently needed. The development of new therapies for HF is hindered by inappropriate or incomplete preclinical studies. In these guidelines, we present a number of recommendations to enhance similarity between HF animal models and the human condition in order to reduce the chances of failure in subsequent clinical trials. We propose different approaches to address safety as well as efficacy of new therapeutic products. We also propose that good practice rules are followed from the outset so that the chances of eventual approval by regulatory agencies increase. We hope that these guidelines will help improve the translation of results from animal models to humans and thereby contribute to more successful clinical trials and development of new therapies for HF.

Prevalence and predictors of ventricular remodeling after anterior myocardial infarction in the era of modern medical therapy

BACKGROUND

The consequences of aggressive therapy following a myocardial infarction (MI) on ventricular remodeling are not well established. Thus, the objective of this study was to analyze the prevalence, clinical characteristics, and predictors of left ventricular remodeling in the era of modern medical therapy.

MATERIAL/METHODS

Clinical characteristics and echocardiographic data were analyzed in 66 consecutive patients with anterior infarction at admission and at 6-month follow-up. Ventricular remodeling was defined as an increase of 10% in ventricular end-systolic or end-diastolic diameter.

RESULTS

In our study, 58% of patients presented with ventricular remodeling. Patients with remodeling possessed higher total plasma creatine kinase (CPK), MB-fraction (CPK-MB), heart rate, heart failure, shortness of breath, and reperfusion therapy than patients without remodeling. In contrast, patients with remodeling had a smaller ejection fraction, E-Wave deceleration time (EDT), and early (E' Wave) and late (A' Wave) diastolic mitral annulus velocity (average of septal and lateral walls), but a higher E/E' than patients without remodeling. Patients with remodeling used more diuretics, digoxin, oral anticoagulants and aldosterone antagonists than patients without remodeling. In the multivariate analyses, only E' Wave was an independent predictor of ventricular remodeling. Each 1 unit increase in the E' Wave was associated with a 59% increased odds of ventricular remodeling.

CONCLUSIONS

In patients with anterior MI, despite contemporary treatment, ventricular remodeling is still a common event. In addition, diastolic function can have an important role as a predictor of remodeling in this scenario.

A novel method for quantifying the in-vivo mechanical effect of material injected into a myocardial infarction

BACKGROUND

Infarcted regions of myocardium exhibit functional impairment ranging in severity from hypokinesis to dyskinesis. We sought to quantify the effects of injecting a calcium hydroxyapatite-based tissue filler on the passive material response of infarcted left ventricles.

METHODS

Three-dimensional finite element models of the left ventricle were developed using three-dimensional echocardiography data from sheep with a treated and untreated anteroapical infarct, to estimate the material properties (stiffness) in the infarct and remote regions. This was accomplished by matching experimentally determined left ventricular volumes, and minimizing radial strain in the treated infarct, which is indicative of akinesia. The nonlinear stress-strain relationship for the diastolic myocardium was anisotropic with respect to the local muscle fiber direction, and an elastance model for active fiber stress was incorporated.

RESULTS

It was found that the passive stiffness parameter, C, in the treated infarct region is increased by nearly 345 times the healthy remote value. Additionally, the average myofiber stress in the treated left ventricle was significantly reduced in both the remote and infarct regions.

CONCLUSIONS

Overall, injection of tissue filler into the infarct was found to render it akinetic and reduce stress in the left ventricle, which could limit the adverse remodeling that leads to heart failure.

The evolution of angiotensin blockade in the management of cardiovascular disease

Dysregulation of the renin-angiotensin system is implicated in many cardiovascular and renal pathologies. Discovery of the renin-angiotensin system represents a major advance in the understanding of hypertension and cardiovascular disease, leading to the development of the anti-angiotensin medications: angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and direct renin inhibitors. Clinical trials have shown that drugs in each of these classes have a protective effect on vascular organs that surpass the protection associated with the lowering of blood pressure alone.

Infarct restraint to limit adverse ventricular remodeling

The left ventricular response to a myocardial infarction is a complex biomechanical process that is only beginning to be understood. Infarct expansion (stretching) is an immediate and progressive phenomenon that is known to initiate and sustain the ventricular dilatation and global loss of contractile function that leads to symptomatic heart failure. Limitation of infarct expansion has, therefore, been identified as a potential therapeutic goal that could reduce the morbidity and cost associated with adverse infarction-induced ventricular remodeling and the symptomatic heart failure that results from it. This review will present experimental work that demonstrates the central importance of infarct expansion to the remodeling process as well as proof-of-concept studies that establish the efficacy of early mechanical infarct restraint for limiting ventricular remodeling after myocardial infarction (MI). Ventricular restraint with polymeric mesh materials (wraps) placed early after MI will be discussed. Data supporting the use of injected acellular biomaterials to alter infarct material properties (stiffness) and geometry (thickness) will also be presented. This approach has been shown to be effective in our laboratory and others in limiting post-infarction remodeling and represents a potential means for limiting infarct expansion early after MI via minimally invasive catheter-based technology.

Early predictors of late dilation and remodeling after thrombolized anterior transmural myocardial infarction

BACKGROUND AND HYPOTHESIS

Dilation of the left ventricle after myocardial infarction is associated with an adverse prognosis. There are no clinical studies on the role viable myocardium in the infarcted area assumes in relation to the development of late ventricular remodeling. The hypothesis of this study was to define the relation between remodeling and the presence of viable but akinetic myocardium in the infarct area and to identify early predictors of left ventricular (LV) dilation at 1 year.

METHODS

In all, 92 consecutive patients with myocardial infarction were divided into two groups according to their ventricular volumes. Group I included 57 patients with normal volumes at discharge (9 +/- 3 days after acute infarction) and after 12 months or with LV dilation at discharge who had a normalization of their volumes over a 12-month period. Group II included 35 patients who, independent of their initial volumes, developed LV dilation during follow-up. Low-dose dobutamine infusion was utilized at discharge for echocardiographic evaluation of contractile recovery of viable myocardial segments.

RESULTS

At the first control, patients in Group I presented an end-diastolic volume index (EDVI) of 100 +/- 7 ml/m2 which decreased to 68.8 +/- 6.5 ml/m2 12 months later (p < 0.0001), and an end-systolic volume index (ESVI) of 47.6 +/- 6.7 ml/m2 at the first control and 30.5 +/- 8.8 ml/m2 after 12 months (p < 0.001). Patients in Group II presented a mean EDVI of 116.2 +/- 8.1 ml/m2 at the first control and 138.8 +/- 8 ml/m2 12 months later (p < 0.001), and a mean ESVI of 68.8 +/- 6.5 ml/m2 at the first control and 79.5 +/- 5.4 after 12 months (p < 0.01). Ventricular mass index (VMI) in Group I increased from 106.4 +/- 11 to 122.3 +/- 15 g/m2 (p < 0.01), while in Group II it decreased from 101.1 +/- 10 to 98.7 +/- 8 g/m2 (p = NS). In Group I, mass-to-volume ratio was 1.15 +/- 0.1 g/ml at the first control and 1.67 +/- 0.1 g/ml 12 months later (p < 0.001), while in Group II it declined from 0.88 +/- 0.1 to 0.69 +/- 0.1 g/ml (p < 0.01). The multivariate analysis revealed that ejection fraction < or = 40%, restrictive filling pattern, wall motion score index > 2.5 in response to dobutamine infusion, and mass-to-volume ratio < or = 1 g/ml, all at discharge, as well as an occluded left anterior descending artery discriminate in favor of late LV dilation and remodeling.

CONCLUSIONS

Correct use of noninvasive strategies should result in early identification of postinfarct patients who are at risk of developing LV remodeling.

Assessment of left ventricular volumes and function by cine-MR imaging depending on the investigator's experience

AIMS

To analyze the reproducibility of LV volumes calculated by cardiac magnetic resonance imaging (CMRI) and to compare them to those obtained by conventional ventriculography.

METHODS

A total of 30 patients with stable ischemic heart disease were prospectively included. Each underwent CMRI twice and ventriculography. Left ventricular end diastolic volume (EDV), end systolic volume (ESV) and LV ejection fraction (EF) were calculated by two radiologists at different level of experience. Intraobserver, interobserver and interstudy variabilities were assessed.

RESULTS

The cut off values were: intraobserver variability (EDV, ESV, EF): 9.4 ml, 5.3 ml, 3.3% for well-trained radiologist; 13.1 ml, 7.5 ml, 4.1% for less-trained radiologist. interobserver variability: EDV: 11.7 and 10.4 ml; ESV: 7.0 and 6.6 ml; EF: 3.9 and 4.2%. interstudy variability (EDV, ESV, EF): 11.6 and 12.6 ml, 7.1 and 7.4 ml, 3.9 and 3.5%, for experienced and less-trained observers. Statistical differences were found between CMRI and ventriculography: CMRI underestimation of EDV and EF, overestimation of ESV.

CONCLUSIONS

CMRI volumetric quantification of LV volumes and function is highly reproducible at different levels of experience, but not interchangeable with those obtained by ventriculography.

Electrocardiographic predictors of proximal left anterior descending coronary artery occlusion

Proximal occlusion of the left anterior descending coronary artery (LAD) results in a less favorable prognosis in coronary angiography. Therefore, it is important to determine whether there are significant lesions in LAD by electrocardiography (ECG) before coronary angiography. Twelve-lead ECG was compared in 130 patients with significant lesions (≥70% stenosis) confined to proximal part of the LAD (P LAD group) and 492 patients with normal coronary angiography (control group). Fifty-nine patients in the P LAD group and 18 patients in the control group had signs of anterior myocardial infarction as shown by ST elevation (≥1.0 mV) in two consecutive pericardial leads or the presence of a pathological Q wave. An inverted U wave (biphasic T wave) in leads V1 to V4 had a sensitivity of 49.3% (35/71) in P LAD patients without signs of anterior myocardial infarction (MI) and 96.6 % (57/59; specificity, 66.6%; positive predictive value, 90.9 %) in the P LAD patients with signs of anterior MI. In the P LAD patients with signs of anterior MI, T inversion in V4–V5 had a lower sensitivity (67.0% [40/59]) than an inverted U wave. ST depression in inferior leads and ST depression in V5 were not useful markers of proximal LAD occlusion. In conclusions, an inverted U wave in V1 to V4 (or in each of these leads) and T inversion in V4–V5 are the best predictors of significant proximal LAD lesion, especially in patients with ECG findings of anterior MI.

Relation between plasma brain natriuretic peptide, serum indexes of collagen type I turnover, and left ventricular remodeling after reperfused acute myocardial infarction

The aim of the study is to investigate the relation between plasma brain natriuretic peptide (BNP), collagen type I turnover, and left ventricular (LV) remodeling after primary angioplasty. Echo-Doppler, BNP, carboxy-terminal telopeptide of procollagen type I (ICTP), C-terminal propeptide of procollagen type I (PICP), and their ratio PICP/ICTP (as an index of coupling between the synthesis and degradation of collagen type I) were evaluated at days 1 and 3 and months 1 and 6 after primary angioplasty in 56 consecutive patients with a first large acute myocardial infarction (AMI). During the 6 months after AMI, a direct relation was shown between BNP and ICTP (day 1, r = 0.54, p = 0.000; day 3, r = 0.64, p = 0.000; month 1, r = 0.64, p = 0.000; month 6, r = 0.41, p = 0.005) and BNP and PICP/ICTP (day 1, r = -0.54, p = 0.003; day 3, r = -0.58, p = 0.000; month 1, r = -0.50, p = 0.000; month 6, r = -0.30, p = 0.043), but not between BNP and PICP. Using analysis of covariance, relations between BNP and ICTP and PICP/ICTP were independent from infarct size. Patients with LV remodeling had significantly higher plasma ICTP and BNP levels and lower PICP/ICTP than patients without LV remodeling. Day-1 ICTP independently predicted 6-month remodeling (exp beta = 2.14, 95% confidence interval 1,120 to 3,550, p = 0.01). In conclusion, a relation exists between plasma BNP collagen type I turnover and LV remodeling after reperfused AMI.

Impact of chronotropic effect of cilostazol after acute myocardial infarction: insights from change in left ventricular volume and function

BACKGROUND

Cilostazol, a phosphodiesterase inhibitor, is an antiplatelet agent with positive chronotropic effect, the impact of which on left ventricular (LV) volume and function in acute myocardial infarction (AMI) was evaluated in the present study.

METHODS AND RESULTS

In 56 patients with AMI treated with primary coronary stenting, serial echocardiographic studies within 24 h and at 6 months were performed. Patients received a conventional antiplatelet regimen either without cilostazol (group 1, n=29) or with cilostazol (group 2, n=27). At 6 months, the difference in the change in heart rate between group 1 and group 2 was statistically significant (9.9 beats/min; p=0.04). However, changes in LV end-systolic volume (LVESV) (7.1+/-8.2 vs 10.0+/-21.7 ml, p=0.60), LV ejection fraction (EF) (8.2+/-9.9 vs 9.0+/-12.6%, p=0.85) and the ratio of early mitral inflow velocity to the mitral annular velocity (E/E') (0.6+/-3.7 vs -1.7+/-3.2) were not different between the 2 groups. Cardiac event rate was similar between the 2 groups. On multivariate regression analyses, cilostazol therapy had no significant influence on the changes in LVESV, LVEF or E/E'.

CONCLUSIONS

In this study, the addition of cilostazol on conventional drug therapy had no adverse influence on LV remodeling or LV function after AMI.

Scale of interest versus scale of estimation: comparing alternative estimators for the incremental costs of a comorbidity

We investigate how the scale of estimation in risk-adjustment models for health-care costs affects the covariate effect, where the scale of interest for the covariate effect may be different from the scale of estimation. As an illustrative example, we use claims data to estimate the incremental costs associated with heart failure within one year subsequent to myocardial infarction. Here, the scale of interest for the effect of heart failure on costs is additive. However, traditional methods for modeling costs use predetermined scale of estimation - for example, ordinary least squares (OLS) regression assumes an additive scale while log-transformed OLS and generalized linear models with log-link assume a multiplicative scale of estimation. We compare these models with a new flexible model that lets the data determine the appropriate scale of estimation. We use a variety of goodness-of-fit measures along with a modified Copas test to assess robustness, lack of fit, and over-fitting properties of the alternative estimators. Biases up to 19% in the scale of interest are observed due to the misrepresentation of the scale of estimation. The new flexible model is found to appropriately represent the scale of estimation and less susceptible to over-fitting despite estimating additional parameters in the link and the variance functions.

Correlation of the Tei Index With Left Ventricular Dilatation and Mortality in Patients With Acute Myocardial Infarction

The Tei index is an echocardiographic index of combined systolic and diastolic function, calculated as isovolumetric relaxation time plus isovolumetric contraction time divided by ejection time. The aim of this study was to define the correlation of the Tei index with left ventricular dilatation and mortality in patients with acute myocardial infarction (AMI). A total of 77 patients (58 men, 19 women) with a mean age of 53 +/- 12 years, who had presented with an AMI in our clinic between June 2001 and February 2002 were compared with a control group of 88 healthy subjects (63 men, 25 women) with a mean age of 55 +/- 6 years. Echocardiographic evaluation was carried out within 24 hours and the third month of AMI, using a 3.5 MHz probe with pulse wave Doppler recordings by the adult cardiac mode of an Acuson C 256 echocardiograph. There were statistically significant differences between the 2 groups in all echocardiographic parameters, except mitral A wave. Thirteen patients died during the follow-up period of 3 months. The Tei index was significantly higher in the patients who died compared with those who survived (0.70 +/- 0.10 versus 0.61 +/- 0.10; P < 0.001). The patients who had heart failure after AMI had a mean Tei index value of 0.76 +/- 0.27, whereas the patients who did not have heart failure after AMI had a significantly lower Tei index value of 0.60 +/- 0.32 (P < 0.05). Patients were divided into 2 groups according to their Tei index. Patients with a > 0.60 Tei index had significantly higher end-systolic and end-diastolic volumes compared to patients with a < 0.60 Tei index (P < 0.001 for both) in the acute phase of AMI. Within 3 months, patients with a Tei index < 0.60 had a significant reduction in end-diastolic volumes (P < 0.01), whereas the end-diastolic volumes did not change significantly in patients with an index > 0.60 (P = 0.19). The Tei index is an important indicator of left ventricular dysfunction and death after AMI. A greater Tei index at the onset of AMI is associated with a higher incidence of subsequent cardiac death, CHF, and progressive LV remodeling.

Relation of terminal QRS distortion to left ventricular functional recovery and remodeling in acute myocardial infarction treated with primary angioplasty

The association between admission electrocardiogram and 6-month change in left ventricular function and volume was assessed in 200 patients who had acute myocardial infarction that was treated with primary percutaneous coronary intervention. Logistic regression analysis indicated peak creatine phosphokinase-MB, number of Q-wave leads, QRS interval distortion, wall motion score index, and angiographic Thrombolysis In Myocardial Infarction flow grade as predictors of no functional recovery and QRS interval distortion and Thrombolysis In Myocardial Infarction flow grade as predictors of left ventricular remodeling.

Reperfusion phenomenon is a strong predictor of left ventricular remodeling after acute myocardial infarction

BACKGROUND

Many clinicians have seen the reperfusion phenomenon, a paradoxical response that includes a transient increase of chest pain, additional ST-segment elevation or ventricular arrhythmias immediately after coronary reperfusion, in patients with acute myocardial infarction (AMI). The aim of the present study was to investigate the impact of this phenomenon during coronary reperfusion on left ventricular (LV) remodeling in patients with AMI.

METHODS AND RESULTS

One hundred and thirty-eight consecutive patients with a first anterior-wall AMI, undergoing coronary reperfusion treatment within 24 h of onset were prospectively evaluated for reperfusion phenomenon and followed up with scheduled evaluations of LV function and morphology with left ventriculography for 1 year. Of the 138 enrolled patients, 77 underwent serial left ventriculography at the acute, subacute and 1-year phases. Of these 77 patients, 39 demonstrated the reperfusion phenomenon. The LV end-diastolic volume index significantly increased from the acute to subacute phase and to the 1-year phase, but was unchanged in the 38 patients without reperfusion phenomenon. In multivariate analysis, reperfusion phenomenon was the only determinant of LV dilatation after AMI.

CONCLUSIONS

Reperfusion phenomenon was a strong predictor of LV remodeling after reperfusion therapy for AMI.

Left Ventricular Remodeling and Systolic Deterioration in Acute Myocardial Infarction: Findings from the Stent-PAMI Study

BACKGROUND

Left ventricular systolic deterioration (LVSD) develops in some patients despite successful percutaneous intervention and medical therapy for myocardial infarction (MI). We sought to determine predictors of LVSD by comparing demographic, procedural, angiographic variables, and 6-month major adverse cardiac events (MACE) in patients with and without LVSD after MI.

METHODS

We performed a posthoc analysis of patients prospectively enrolled in the Stent-PAMI trial if they had successful percutaneous intervention for MI (<50% residual stenosis and TIMI-3 grade flow), normal left ventricular systolic function on index ventriculogram, and protocol driven coronary angiography with ventriculography at 6 months. We defined LVSD as an absolute decrease in ejection fraction > or =15% compared to baseline value.

RESULTS

Of the 900 patients enrolled in Stent-PAMI, 187 patients met the inclusion criteria. LVSD developed in 30 patients (16%) and occurred independent of demographic, procedural, angiographic variables, and 6-month MACE. Multivariate predictors of LVSD were higher baseline ejection fraction (P = 0.0065, OR 1.09; 95% CI = 1.02-1.16) and peak creatine phosphokinase (CPK) level (P = 0.0022, OR 1.04; 95% CI = 1.02-1.07).

CONCLUSIONS

LVSD occurs in a minority of patients despite successful mechanical reperfusion and occurred independent of procedural, angiographic variables, target vessel revascularization, reinfarction, and combined MACE. Infarct size (determined by peak CPK) and high baseline ejection fraction predicted development of LVSD at 6 months. LVSD in this population likely occurred by negative left ventricular remodeling.

Time-dependent changes in plasma osteopontin levels in patients with anterior-wall acute myocardial infarction after successful reperfusion: Correlation with left-ventricular volume and function

Osteopontin is a secreted extracellular-matrix glycoprotein that plays a role in the healing of remodeling tissue. We examined the relationship of plasma osteopontin levels with left-ventricular (LV) volume and function in 18 consecutive patients who underwent successful reperfusion after anterior-wall acute myocardial infarction (AMI). The plasma osteopontin level was within the control range at admission (mean +/- SD 420 +/- 195 ng/mL), began to increase on day 2 (935 +/- 464 ng/mL), and reached a maximum around day 3 (1139 +/- 482 ng/mL). The level remained high on days 4, 5, and 7 ( approximately 1000 ng/mL) and then decreased on day 14. Maximal plasma osteopontin levels and the difference between maximal and minimal levels were positively correlated with LV end-systolic volume index (r = .58, P < .05; and r = .65, P < .01, respectively) and negatively correlated with LV ejection fraction (r = -.52, P < .05; and r = -.60, P < .01, respectively). The area under the curve of plasma osteopontin levels for 14 days after AMI was significantly correlated with LV end-systolic volume index (r = .66, P < .01), LV end-diastolic volume index (r = .50, P < .05), and LV ejection fraction (r = -.55, P < .05). In subgroup patients with the same area of risk for myocardial infarction (ie, responsible lesions located at the same proximal left anterior descending coronary artery), essentially the same or a closer relationship between plasma osteopontin level and LV volume and function was noted. Plasma osteopontin levels were correlated substantially with plasma levels of high-sensitivity C-reactive protein (hsCRP) and weakly with serum creatine kinase release. In conclusion, the plasma level of osteopontin changes in a time-dependent fashion and is correlated with LV volumes and function and associated substantially with the extent of the inflammatory response indicated by the plasma hsCRP level and weakly with infarct size estimated on the basis of cardiac-enzyme release.

Prevention and Reversal of LV Remodeling with Neurohormonal Inhibitors

Left ventricular (LV) remodeling refers to alterations in ventricular mass, chamber size, and shape that result from myocardial injury, pressure, or volume overload. Numerous studies have demonstrated that LV remodeling correlates with the incidence of heart failure and death, supporting a causative role for remodeling in heart failure progression. Heart failure trials have shown that neurohormonal antagonists, including angiotensin-converting enzyme (ACE) inhibitors and beta-adrenergic receptor blockers (beta blockers), reduce remodeling in parallel with improved clinical outcomes. Existing data favor using angiotensin II type 1 (AT1) receptor antagonists (or "ARBs"), although their anti-remodeling effects are less well established. Recently, mineralocorticoid receptor antagonists have gained substantial interest based on favorable clinical trial results, although data regarding their effects on remodeling are limited. Thus, an optimal medical regimen to prevent or limit LV remodeling in patients with LV dysfunction should include both an ACE inhibitor and beta-adrenergic receptor antagonist, irrespective of the degree of LV dysfunction and symptom status. For patients intolerant to ACE inhibitors, an AT1 receptor antagonist should be substituted. An aldosterone antagonist should be administered to patients with severe, New York Heart Association class III to IV heart failure who have normal or only mildly impaired renal function, or to those patients with depressed LV function following an acute myocardial infarction. Through the aggressive pharmacologic inhibition of both the renin-angiotensin-aldosterone and sympathetic nervous systems, progressive LV remodeling can be prevented or hindered, thereby favorably altering the natural history of the heart failure syndrome.

Monitoring change in the three-dimensional shape of the human left ventricle

BACKGROUND

Characterizing left ventricular (LV) remodeling after myocardial infarction or LV shape change resulting from LV shape-restoration operation can yield valuable prognostic information. However, current methods measure only global parameters of LV shape.

METHODS

We developed and validated a method for measuring change in regional LV shape by aligning a patient's follow-up 3-dimensional LV surface reconstruction to baseline surface. We tested the diagnostic power of 6 distance functions to detect a known shape deformation. To create the test data, the LV endocardial surface of a control subject was reconstructed using 3-dimensional echocardiographic techniques. The surface was deformed 9 different ways to model LV dilation (3 different locations and severities). Normal shape variability was defined from 18 serial studies of 6 control subjects. The severity of regional dilation was computed as the orthogonal distance between the aligned baseline and deformed LV surfaces. Deformation was quantified according to regional location using the 16-segment map of the LV.

RESULTS

Normal LV shape variability was 3.38 mm. The LV deformations ranged from 2.95 to 8.02 mm. Gaussian distance function produced the highest accuracy for measuring deformation distances (P <.005 by analysis of variance). In addition, the gaussian function correctly identified the location of the maximum deformation in 6 of the 9 distorted surfaces. In the 3 remaining surfaces, the gaussian alignment selected an adjacent basal segment with a similar deformation distance (mean error: 0.2 +/- 0.17 mm). The gaussian function's accuracy in pinpointing the deformation equaled or exceeded the performance of the other 5 functions tested.

CONCLUSION

This new method of aligning 3-dimensional LV surfaces in space facilitates detecting, measuring, and localizing regional shape change in the human LV independent of anatomic landmarks or geometric references. Potential applications include quantitative monitoring of change in regional LV shape after a pathologic process and/or surgical procedure to document efficacy of treatment and to assess prognosis.

Selective microembolization of the circumflex coronary artery in an ovine model: dilated, ischemic cardiomyopathy and left ventricular dysfunction

BACKGROUND

Ventricular remodeling often occurs after myocardial infarction, yet the natural history remains unpredictable because of the chronicity of the process and therapeutic interventions involved. We induced cardiac dysfunction in an ovine model via selective microembolization of the circumflex coronary artery (LCx) to test the hypothesis that ventricular remodeling progresses following coronary microembolization for up to 24 months. Methods and results Sheep underwent weekly selective microembolization of the LCx until left ventricular ejection fraction stabilized <35% for 2 consecutive weeks. In a subgroup carried out to 4 months, the end-systolic pressure-volume relationship slope decreased from 2.3+/-0.6 (baseline) to 1.3+/-0.5 at month 4 (P<.05). In a second group, echocardiography at 24 months, the ejection fraction decreased from 51+/-3% (baseline) to 25+/-2% (month 5) (P<.05) and stabilized through month 24 (23+/-5%, P<.05), whereas left ventricular end-systolic area and left ventricular end-diastolic area increased by 222% and 98%, respectively, through month 24.

CONCLUSIONS

Selective microembolization of the LCx induces left ventricular dysfunction followed by dilated, ischemic cardiomyopathy, which continues to progress for up to 2 years despite stabilization of left ventricular ejection fraction. This model of ventricular remodeling secondary to microinfarction may be a useful experimental platform for large animal heart failure investigations.

Early Definition of Treatment Outcomes After Reperfusion Therapy for Myocardial Infarction

AIMS

Early definition of treatment outcomes, including coronary patency and infarct size, after reperfusion therapy for myocardial infarction (MI) is desirable to identify patients requiring further intervention.

METHODS AND RESULTS

Patients receiving reperfusion therapy for a first MI had continuous 12-lead ST segment monitoring to document reperfusion and ischaemia time. Infarct size was measured by 12-lead QRS score and radionuclide scintigraphy ((201)Tl single-photon emission computed tomography, SPECT) at 1 week, and left ventricular function by echocardiography at 1 week and 1 month. Resolution of ST elevation accurately detected TIMI 2 or 3 reperfusion (predictive accuracy 93%) in 55 patients undergoing immediate angioplasty, but ST recovery was delayed (17+/-14min) after angiographic reperfusion. A multivariate model, including risk region and ischaemia time, accurately predicted MI size (R(2)=0.80, P<0.00001) in these patients. The same model, prospectively applied on Day 1 to 154 patients receiving thrombolytic therapy, accurately predicted MI size, measured by QRS score (R(2)=0.88, P<0.0000001) and (201)Tl SPECT (R(2)=0.75, P<0.000001) at 1 week for individual patients. Regional myocardial wall motion at 1 month was directly correlated with MI size predicted by the model on Day 1 (r=0.73, P<0.0001).

CONCLUSIONS

Use of ST segment monitoring during reperfusion therapy facilitates early prediction of treatment outcomes, including coronary reperfusion, infarct size and ventricular function.

Exercise at ventilatory threshold aggravates left ventricular remodeling in patients with extensive anterior acute myocardial infarction

BACKGROUND

The effects of physical training on ventricular remodeling after extensive anterior acute myocardial infarction (AMI) have not yet been defined. This randomized controlled study examines whether exercise aggravates left ventricular (LV) remodeling in patients with extensive anterior AMI.

METHODS

Forty-eight consecutive patients with a first extensive anterior AMI and an LV ejection fraction (EF) of <45% assessed with left ventriculography (LVG) within 3 days of onset were randomly allocated to a training group (n = 24) or a control group (n = 24). Exercise intensity was determined by the heart rate of each patient at ventilatory threshold (VT). Three weeks after onset, a second LVG was performed, followed by a supervised exercise program at VT for 12 weeks. The LVG was reassessed after the exercise program. We then calculated the global LV volume (end-diastolic volume index [EDVI], end-systolic volume index [ESVI]) and systolic expansion volume index (SEVI), a new parameter for measuring the infarction site expansion at the end-systolic phase.

RESULTS

Both EDVI and ESVI significantly decreased in the control group from 1 to 4 months after onset (91.2 +/- 26.1 to 83.3 +/- 24.0 mL/m2, P <.05; 52.4 +/- 22.5 to 45.7 +/- 18.8 mL/m2, P <.01, respectively), but not in the exercise group. The SEVI also significantly decreased in the control group from 1 to 4 months (33.1 +/- 16.9 to 25.7 +/- 13.9 mL/m2, P <.05), but not in the training group (34.2 +/- 12.9 to 36.5 +/- 15.5 mL/m2, P = not significant).

CONCLUSION

Exercise while healing in patients with extensive anterior AMI, even at the VT level, induces LV enlargement and thus might aggravate LV remodeling. Therefore, in these patients, clinicians should consider withholding exercise training for at least 8 weeks, versus the 3-week period used in this trial.

Effects of dobutamine on left ventricular shape and geometry: an easy way to detect the functional status of chronic heart failure in patients with dilated cardiomyopathy

OBJECTIVE

Changes in left ventricular geometry and shape are prominent characteristics of cardiomyopathy. The aim of this study was to investigate left ventricular geometry and shape changes after inotropic stimulation in patients with chronic nonischemic dilated cardiomyopathy.

METHODS

A low infusion rate echocardiography-dobutamine study was performed in 35 consecutive patients (age: 50 +/- 8 years) with known dilated cardiomyopathy. Peak exercise oxygen consumption was measured the day before. Overall left ventricular chamber shape was assessed by using the long-/minor-axis dimension ratio obtained at end-diastole and end-systole.

RESULTS

After dobutamine infusion, in the entire study group an increase in systolic long-/minor-axis dimension ratio (0.11 +/- 0.13 mm, P <.001) was observed. The study population was further divided according to whether peak exercise oxygen consumption was less (group I) or more (group II) than 14 mL/kg/min. Although at baseline systolic long-/minor-axis dimension ratio was similar between groups, after dobutamine infusion it was higher in group II (1.51 +/- 0.19) than in group I (1.31 +/- 0.2, P <.01) indicating the abnormal response of systolic sphericity index to inotropic stimulation in patients with advanced functional class heart failure.

CONCLUSION

The response of systolic sphericity index to dobutamine infusion might be an alternative index of the functional status of the failing heart in patients with nonischemic dilated cardiomyopathy.

Left ventricular remodeling after primary coronary angioplasty: patterns of left ventricular dilation and long-term prognostic implications

BACKGROUND

We prospectively evaluated the prevalence, pattern, and prognostic impact of left ventricular (LV) remodeling after acute myocardial infarction (AMI) successfully treated with primary PTCA. The prevalence, course, and prognostic value of LV remodeling after primary PTCA are still to be clarified.

METHODS AND RESULTS

In 284 consecutive patients with AMI treated with primary PTCA, serial echocardiographic and angiographic studies, within 24 hours (T1), at 1 (T2) and 6 months (T3) after AMI were performed. Long-term (61+/-14 months) clinical follow-up data were collected for 98.6% patients enrolled in the study. Overall, 85 (30%) patients showed LV dilation (>20% end-diastolic volume increase) at T3 as compared with T1. Early (from T1 to T2), late (from T2 to T3), and progressive dilation patterns (from T1 to T2 to T3) were detected in 42 (15%), 41 (14%), and 36 (13%) patients, respectively. Cardiac death and combined events rate was significantly higher among patients with than among those without LV dilation (P=0.005 and P=0.025, respectively). The pattern of LV dilation during 6 months did not significantly affect survival. Cox survival analysis identified end-systolic volume at T1 and age as baseline predictors and end-systolic volume at T3 and age as 6-month predictors of cardiac death, respectively.

CONCLUSIONS

LV remodeling after successful PTCA occurs despite sustained patency of the infarct-related artery and preservation of regional and global LV function. LV dilation at 6 months after AMI but not the specific pattern of LV dilation is clearly associated with worse long-term clinical outcome.

[Usefulness of the electrocardiogram in predicting the occlusion site in acute anterior myocardial infarction with isolated disease of the left anterior descending coronary artery]

INTRODUCTION AND OBJECTIVES

In acute anterior myocardial infarction (AMI), the site of occlusion in the left anterior descending coronary artery (LAD) is related to the extension of myocardial necrosis and the prognosis. The aim of this study was to assess the value of the electrocardiogram (ECG) as a predictor of the LAD occlusion site in patients with anterior AMI.

METHODS

Forty-five consecutive patients with a first anterior AMI and isolated disease of the LAD were included. We evaluated retrospectively the ECG with the most pronounced ST-segment changes before fibrinolysis and correlated the findings with the site of LAD occlusion in angiography before hospital discharge in relation to the first dominant septal and first diagonal branch: first septal affected (S), first diagonal affected (D), both affected (S + D), or neither affected were considered.

RESULTS

ST depression in leads II, III, or aVF strongly predicted proximal LAD occlusion in S + D, S, and D (p = 0,003, p = 0,04, and p = 0,02, respectively). ST elevation in leads II, III, or aVF was observed only in the presence of wrap-around LAD and was related with occlusion distal to the first diagonal branch. ST elevation > or = 3 mm in lead V1 was a specific predictor of occlusion proximal to first septal (S, p = 0,01). ST elevation in aVR was associated with proximal LAD occlusion in S + D and S (p = 0,03 and p = 0,03, respectively) and absence of coronary collateral circulation.

CONCLUSIONS

In anterior AMI and isolated LAD disease, the ECG can be useful in predicting the LAD occlusion site in relation to its major side branches.

Extension of borderzone myocardium in postinfarction dilated cardiomyopathy

This study tests the hypothesis that hypocontractile, borderzone myocardium adjacent to an expanding infarct becomes progressively larger and more hypocontractile as remodeling continues. Early infarct expansion following anteroapical myocardial infarction (MI) is associated with progressive ventricular dilation and heart failure. The contribution of perfused, hypocontractile, borderzone myocardium to this process is unknown. Using a sheep model of anteroapical infarction, sonomicrometry array localization and serial microsphere injections were used to track changes in regional myocardial contractility, geometry, and perfusion. Eight sheep were studied before and after infarction and two, five, and eight weeks later. Thirty intertransducer chord lengths were analyzed to measure regional contractility and serial changes in regional geometry at end systole. Beginning as a narrow band of fully perfused hypocontractile myocardium adjacent to the infarction, borderzone myocardium extends to involve additional contiguous myocardium that progressively loses contractile function as the heart remodels. Three distinct myocardial zones develop as a result of transmural MI: infarct, borderzone (perfused but hypocontractile), and remote (perfused and normally functioning).This study demonstrates that hypocontractile, fully perfused borderzone myocardium extends to involve contiguous normal myocardium during postinfarction remodeling. This borderzone myocardium is a unique type of perfused, hypocontractile myocardium, which is distinct from hibernating or stunned myocardium. Preventing extension of borderzone myocardium by medical or surgical means offers the prospect of preventing late-onset heart failure following transmural expanding MIs.

Approaches to statistical analysis of repeated echocardiographic measurements after myocardial infarction and its relation to heart failure: Application of a random-effects model

BACKGROUND

Extensive left ventricular (LV) dilatation after myocardial infarction (MI) is associated with increased heart failure risk.

AIMS

To investigate whether the power to demonstrate the relation between LV dilatation and heart failure depends on the method applied to predict LV dilatation after MI.

METHODS

A random-effects model and ANOVA model for repeated measurements (MANOVA) were applied to predict LV volume index during 1 year for 298 post-MI patients. Spearman correlation coefficients (r) were calculated and Cox regression analysis was used to calculate risk ratio's (RR).

RESULTS

LV volume indices were more accurately predicted by a random-effects model than by a MANOVA model (systolic/diastolic respectively r = 0.93/0.91 vs. r = 0.67/0.64). Furthermore, patients with high LV volume index as predicted by the random-effects model, had significantly increased heart failure risk (systolic RR 2.04 (95% CI: 1.31 to 3.17; P = 0.001), diastolic RR 1.80 (95% CI: 1.16 to 2.78; P = 0.007). Using the same data, MANOVA failed to demonstrate this relation significantly (systolic RR 1.77 (95% CI: 0.79 to 3.98; P = 0.16), diastolic RR 1.49 (95% CI: 0.68 to 3.30; P = 0.31).

CONCLUSION

When analyzing repeated measurement data, random-effect models are more powerful in detecting clinical relations than are MANOVA models, especially in the presence of missing values.

Cardiac remodelling in the era of aggressive medical therapy: does it still exist?

AIM

To delineate the natural history of left ventricular remodelling following large anterior myocardial infarction (MI), in the era of aggressive medical therapy.

METHODS

Seventeen selected patients underwent cardiovascular magnetic resonance (CMR) at 2 weeks and 1, 3, 6 and 12 months post infarction.

RESULTS

There was a significant increase in left ventricular (LV) end-diastolic volume index (EDVI) and LV ESVI from 2 weeks to 1 month (P<0.05) but no significant change thereafter. The LV ejection fraction (EF) decreased from 2 weeks to 1 month (P<0.05) and then increased over the year (P=0.02). Throughout the study period the sphericity index increased. There was a significant and progressive decrease in LV mass index over the year, which was associated with a decrease in wall thickness at both the infarct and non-infarct sites. Independent predictors of an early increase in LVESVI were increasing age, increasing CK-MB and not receiving treatment with a statin.

CONCLUSION

This study delineates the natural history of left ventricular remodelling in the modern medical era in those patients who have suffered a large anterior MI. Classical remodelling occurred up to 1 month, but thereafter was attenuated. These findings would suggest that remodelling is not as prevalent in the modern era, and that combined medical management with thrombolysis, ACEi, beta-blockers and statins may strongly influence the development of this remodelling.

Characterization of myocardial hypertrophy by DNA content, PCNA expression and apoptotic index

BACKGROUND

At present little is known about the biological basis of cellular alterations in myocardial hypertrophy. The present study aims to analyze proliferating cell nuclear antigen (PCNA) expression, DNA content and apoptosis, in several types of myocardial hypertrophy in order to define the biological characteristics of this process.

METHODS

The biological parameters were investigated in normal hearts (n=4) and in 21 cases of left ventricular myocardial hypertrophy related to pressure overload (n=7), post-infarction remodeling (n=8) and hypertrophic cardiomyopathy (HCM) (n=8).

RESULTS

The analyzed biomarkers were similar in hypertension and in remodeling, with a very high apoptotic index (mean values: 8.1 and 8.5%, respectively), a low PCNA positivity (mean values: 1.8 and 1.6%) and a prevalent diploid DNA content (DNA index: 1.2). Conversely, HCM showed a high mean PCNA index (21.2%) associated with a prevalence of hyperdiploid myocytes (DNA index: 1.8) and a low number of apoptotic cells (mean value: 1.7%).

CONCLUSIONS

There are significant biological differences between hypertrophy in HCM and that related to arterial hypertension and post-infarction remodeling. Therefore, the combined evaluation of DNA content, PCNA and apoptotic indices could provide a powerful diagnostic tool in doubtful cases of myocardial primary or secondary hypertrophy and open new avenues in the clinical treatment of these entities.

Time course and determinants of left ventricular function recovery after primary angioplasty in patients with acute myocardial infarction

OBJECTIVES

We sought to evaluate the importance of time in relation to treatment, time course and determinants of recovery of left ventricular (LV) function in patients with acute myocardial infarction (AMI) undergoing primary percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

Myocardial salvage has been shown to be dependent on the time elapsed from the onset of AMI to reperfusion.

METHODS

Left ventricular function was evaluated at hospital admission, after angioplasty, at 24 h and 6 months by both echocardiography and angiography and at 1, 7, 30, 90 and 180 days by echocardiography in 101 consecutive patients.

RESULTS

Patients were allocated to three groups according to interval between symptom onset and angioplasty: <2 h (group A), 2 to 4 h (group B) and >4 h (group C). Patients in groups A and B showed a progressive improvement of LV function between day 7 and day 90, which became statistically significant at day 30 (p < 0.01). No LV function changes were noted in group C patients. Thrombolysis In Myocardial Infarction (TIMI) flow grade <3 at 24 h was not associated with any significant change in LV volume and function during the six-month follow-up period. Restenosis, when associated with TIMI flow grade 3 in the infarct-related vessel, did not influence LV function. Flow grade <3 of the infarct-related artery was not associated with any improvement of cardiac events independently from the time to treatment at the initial procedure.

CONCLUSIONS

Patients undergoing primary PTCA for AMI have a good recovery of LV function if TIMI flow grade 3 is restored within 4 h. Coronary angioplasty limits further remodeling of the LV in patients treated after 4 h.

Postinfarctional remodeling: increased dye intensity in the myocardial risk area after angioplasty of infarct-related coronary artery is associated with reduction of ventricular volumes

OBJECTIVES

We sought to evaluate if angiographic dye videointensity of the risk area during percutaneous transluminal coronary angioplasty (PTCA) of the infarct-related artery (IRA) relates to remodeling.

BACKGROUND

Poor reflow after myocardial infarction (MI) predicts worse ventricular remodeling.

METHODS

Fifty-three patients with a first anterior MI and isolated disease of the left anterior descending (LAD), who underwent "primary" (n = 14), "rescue" (n = 7) or "late" (after 10 +/- 4 days, n = 32) PTCA, were retrospectively selected. In 10 patients prospectively collected, we assessed Doppler flow velocities and Doppler flow reserve (DFR), relating them to the videointensity technique. Coronary stenosis and TIMI flow were determined, and echocardiographic volumes (end-diastolic and end-systolic volume indexes) and regional asynergy were computed before hospital discharge (baseline) and at six months. Assuming higher peak videointensity reflects greater myocardial blood volume, a 1- to 5-point (poor-optimal) perfusion scale was devised.

RESULTS

The correlation of Doppler peak velocity and DFR with videointensity was significant (r = 0.58, p = 0.007 and r = 0.71, p < 0.001, respectively). Patients were subdivided into group A (increased videointensity post-PTCA > or = 1.5 points, n = 29) and group B (unchanged videointensity, n = 24). Analysis of variance showed a time-group interaction for end-diastolic volume index (-4.6 +/- 23% vs. +22 +/- 22%, p = 0.003) and end-systolic volume index (-3.05 +/- 11.1% vs. +4.1 +/- 12.5%, p = 0.027). There was no interaction for changes in LAD stenosis (p = 0.39) and TIMI flow after PTCA (p = 0.27), or regional asynergy at six months (p = 0.31).

CONCLUSIONS

Angiographic dye videointensity in the risk area correlates with Doppler peak velocity and DFR, and its increase after PTCA of IRA has a limiting effect on ventricular volumes, independent of coronary stenosis resolution, changes in Thrombolysis In Myocardial Infarction (TIMI) flow or extent of regional asynergy.

Influence of treatment delay on long-term left ventricular function in patients with acute myocardial infarction successfully treated with primary angioplasty

BACKGROUND

Myocardial salvage has been shown to be dependent on the time elapsed from the onset of acute myocardial infarction (AMI) to reperfusion. The aim of this study was to evaluate the importance of time to reperfusion for left ventricular function recovery after primary angioplasty (percutaneous transluminal coronary angioplasty [PTCA]) for AMI.

METHODS

Ninety-five patients undergoing long-term successful PTCA for AMI were studied. Echocardiography was performed before and 3, 7, 30, 90, and 180 days after PTCA. End-diastolic volume index (EDVI) and end-systolic volume index (ESVI), ejection fraction, and left ventricular wall motion score index (WMSI) were evaluated.

RESULTS

Patients were divided into group A, 23 patients reperfused within 2 hours; group B, 32 patients reperfused between 2 and 4 hours; group C, 22 patients reperfused between 4 and 6 hours; and group D, 18 patients reperfused between 6 and 12 hours. Both EDVI and ESVI were reduced in groups A and B at 90 days. Groups C and D did not show any changes of EDVI and ESVI at any stage throughout the study. Ejection fraction improved only in groups A and B at 30, 90, and 180 days. At study entry, WMSI was similar in all groups. After 7 days, in group A and in group B, WMSI was improved, no changes were observed in group C, and a mild deterioration was observed in group D at 3 and 7 days. Subsequent evaluations showed progressive improvement of WMSI in all groups.

CONCLUSIONS

Myocardial salvage is achieved only in patients revascularized within 4 hours from AMI onset. However, revascularization after 6 hours may be worthwhile by preventing ventricular remodeling.

The beating open heart for rebuilding ventricular geometry during surgical anterior restoration

Heart failure is an increasing problem because of successful therapies in younger age groups and an overall increase in age in the general population. Ischemic cardiomyopathy secondary to myocardial infarction is the most prevalent entity among the several causes for cardiac failure. Among the surgical options for these patients, neither transplantation nor current ventricular assist devices are able to treat a sufficient number of patients. Ventricular restoration, however, may evolve as a surgical option to treat myocardial failure secondary to postinfarction ventricular dilatation. This procedure must be undertaken in high-risk coronary artery bypass graft (CABG) patients in heart failure. We describe the techniques for both the conventional procedure (CABG +/- mitral valve [MV] repair) using cardioplegic methods, and the beating open heart for surgical anterior ventricular restoration (SAVR) for dyskinetic and akinetic areas in ischemic cardiomyopathies. This combined approach allows safe restoration of the ventricular geometry with minimal use of mechanical support (ie, intra-aortic balloon pump [IABP]) in 195 consecutive patients undergoing this procedure by members of an international team called the RESTORE group.

Heterogeneity of left ventricular remodeling after acute myocardial infarction: results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-3 Echo Substudy

BACKGROUND

Left ventricular (LV) remodeling after acute myocardial infarction has still to be clarified in the thrombolytic era.

METHODS

To evaluate timing and the magnitude and pattern of postinfarct LV remodeling, a subset of 614 patients enrolled in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-3 Echo Substudy underwent serial 2-dimensional echocardiograms at 24 to 48 hours from symptom onset (S1), at hospital discharge (S2), at 6 weeks (S3), and at 6 months (S4) after acute myocardial infarction.

RESULTS

During the study period the end-diastolic volume index (EDVi) increased (P <.001) and wall motion abnormalities (%WMA) decreased (P <.001), whereas ejection fraction (EF) remained unchanged. Nineteen percent of patients showed a > 20% increase in EDVi at S2 compared with S1 (severe early dilation), and 16% of patients showed a > 20% dilation at S4 compared with S2 (severe late dilation). Independent predictors of severe in-hospital LV dilation were relatively small EDVi (odds ratio [OR] 0.961, 95% confidence interval [CI] 0.947-0.974, P =.0001) and relatively large %WMA (OR 1.030, 95% CI 1.013-1.048, P =.0005). Similarly, smaller predischarge EDVi (OR 0.975, 95% CI 0. 963-0.987, P =.0001), greater %WMA (OR 1.026, 95% CI 1.008-1.045, P =.0042), and moderate to severe mitral regurgitation (OR 2.261, 95% CI 1.031-4.958, P = 0.0417) independently predicted severe late dilation. Importantly, 92% of the patients with severe early dilation did not have further dilation at S4, and 91% of patients with severe late dilation did not have in-hospital dilation. EF was unchanged over time in patients with early dilation, whereas it significantly decreased in those with late dilation.

CONCLUSIONS

Although in-hospital LV enlargement is not predictive of subsequent dilation and dysfunction, late remodeling is associated with progressive deterioration of global ventricular function over time: patients with extensive %WMA and not significantly enlarged ventricular volume before discharge are at higher risk for progressive dilation and dysfunction.

Long-term effects of bisoprolol compared with imidapril on left ventricular remodeling after reperfusion in acute myocardial infarction: an angiographic study in patients with maintained vessel patency

BACKGROUND

Although angiotensin-converting enzyme inhibitor attenuates ventricular enlargement, whether beta-blocker therapy induces regression of left ventricular remodeling is not known. The purpose of this study was to compare the effects of bisoprolol therapy with those of imidapril therapy on left ventricular remodeling after acute myocardial infarction (AMI).

METHODS

Sixty patients with AMI who underwent reperfusion therapy were randomly assigned to an imidapril group (20 patients), a bisoprolol group (20 patients), or a control group (20 patients). Administration was started within 24 hours. Left ventricular function on admission and 3 months and 1 year after AMI was investigated.

RESULTS

Baseline characteristics on admission were similar in the 3 groups except for sex distribution. Mean pulmonary capillary wedge pressure and left ventricular end-diastolic pressure in the bisoprolol group were higher than those in the imidapril group 1 year after admission (pulmonary capillary wedge pressure: 12 +/- 7 vs 8 +/- 2 mm Hg, left ventricular end-diastolic pressure: 17 +/- 8 vs 11 +/- 4 mm Hg, P <. 01). Left ventricular end-diastolic volume index (EDVI) increased in the bisoprolol group throughout the 1-year period (P <.01), whereas EDVI in the imidapril group decreased (P <.01). The increases in EDVI during 1 year in the bisoprolol group were greater than those of the other 2 groups (bisoprolol: 12 +/- 10, imidapril: -9 +/- 7, control: 4 +/- 11 mL/m2, P <.01).

CONCLUSIONS

Early treatment with bisoprolol in AMI cannot prevent left ventricular remodeling, whereas imidapril attenuates left ventricular dilation by decreasing preload.

Ventricular remodeling and the renin angiotensin aldosterone system

Ventricular remodeling in patients with left ventricular systolic dysfunction is an indolent process that is associated with a poor prognosis. Clinical and experimental data support the central role played by the renin-angiotensin-aldosterone system in the pathophysiology of remodeling. ACE inhibitors improve the natural history of ventricular remodeling and the syndrome of heart failure. Experimental and preliminary clinical data suggest that angiotensin II type I receptor blockade also impacts favorably on remodeling. Some experimental studies suggest a possible synergistic effect when combining ACE inhibitors and angiotensin II type I receptor antagonists. Aldosterone, the regulation of which, in part, is independent of angiotensin II, is a direct mediator of the interstitial component of remodeling, and its blockade has been found to improve clinical outcomes. Future research will more precisely define the mechanism for ventricular remodeling and will yield more effective means of achieving a clinically relevant impact on this process. (c)2000 by CHF, Inc.

Effects of surgery for postinfarction ventricular tachycardia on parameters of left ventricular function

Heart failure is the leading cause of death in patients after surgery for ventricular tachycardia. This study examines the effects of antiarrhythmic surgery on 4 parameters of left ventricular (LV) function. Global ejection fraction, segmental wall motion score, homogeneity of contraction, and diastolic function were measured in 32 patients by technetium-99m radionuclide ventriculography. Ejection fraction was measured from the left anterior oblique image. Wall motion score was assessed semiquantitatively for 11 LV segments from 3 projections. Homogeneity of contraction was expressed as the SD of the LV phase analysis curve during systole from the left anterior oblique image. Diastolic function was expressed in terms of peak and mean first time derivative of the action potential (dV/dt) of the LV function curve. Subgroup analyses were performed to distinguish the effects of aneurysmectomy, coronary artery bypass grafting, and changes in angiotensin converting enzyme inhibitor therapy. Mean systolic function improved after surgery (ejection fraction 22% vs 32%, p <0001; wall motion score 20 vs 13, p <0.0001; phase analysis 18 vs 12, p <0.03). Mean diastolic function also improved (peak dV/dt 0.83 +/- 0.32 vs 1.49 +/- 0.39, p = 0.006; mean dV/dt 0.41 +/- 0.15 vs 0.76 +/- 0.27, p = 0.006). Improvements were not confined to those who had aneurysmectomy or coronary bypass grafting and were not explained by changes in vasodilator therapy. Thus, antiarrhythmic surgery does not inherently damage LV function. Significant improvements were observed in most patients. Failure to improve indicated a poor longer term prognosis.

Early angiotensin converting enzyme inhibitor therapy enhances the benefits of late coronary artery reperfusion on infarct expansion

BACKGROUND

Individually, both late reperfusion and early angiotensin converting enzyme (ACE) inhibitor treatment prevent infarct expansion after acute myocardial infarction.

OBJECTIVE

To examine the effect and mechanism of early post-myocardial infarction ACE inhibitor treatment, when used in combination with late coronary artery reperfusion, on infarct expansion.

METHODS

Sprague-Dawley rats underwent 8 h of coronary occlusion followed by permanent reperfusion. The treatment group received enalapril, started 1 h after coronary occlusion and continued for 13 days. A control group received placebo. Two weeks after acute myocardial infarction, hemodynamic, morphometric and histologic analyses were performed.

RESULTS

Hemodynamic parameters were similar in both groups (P = NS). Infarct size was similar in the ACE inhibitor and placebo treatment groups (44 +/- 4% compared with 39 +/- 4%, P = NS). Septal thickness was also similar in the two groups (2.8 +/- 0.3 mm compared with 2.7 +/- 0.3 mm, P = NS). The ACE inhibitor-treated group had thicker infarcts than those in the placebo-treated group (0.93 +/- 0.07 mm compared with 0.76 +/- 0.04 mm, P < 0.05) and these infarcts were less expanded (expansion index 1.17 +/- 0.12 compared with 1.57 +/- 0.12, P < 0.05). ACE inhibitor treatment was associated with hypertrophy of viable myocytes within the scar compared with placebo treatment (cell diameter 11.1 +/- 0.5 microns compared with 8.9 +/- 0.4 microns, P < 0.01).

CONCLUSIONS

Early post-myocardial infarction ACE inhibitor treatment enhances the benefits of late coronary reperfusion on infarct expansion. The benefits may be related to hypertrophy of still-viable myocytes within the infarcted zone.

Ventricular remodeling in active myocarditis. Myocarditis Treatment Trial

BACKGROUND

Remodeling of the left ventricle with the development of a spherical cavity occurs in dilated cardiomyopathy and is associated with a poor long-term prognosis. The early effects of myocarditis on left ventricular geometry have not been previously described or correlated with clinical outcome.

METHODS

The baseline echocardiograms of 35 patients with biopsy-confirmed myocarditis were compared with 20 normal controls. Left ventricular end-diastolic volume, long axis length, and mid-cavity diameter were measured. The degree of sphericity was expressed as the ratio of the mid-cavity diameter to the long axis length. Left ventricular ejection fraction was assessed by radionuclide angiography.

RESULTS

In patients with myocarditis, mean left ventricular volume of 81 +/- 29 mL/m(2) was significantly greater than 50 +/- 8 mL/m(2) in controls (P =.001). Chamber dilatation occurred primarily along the mid-cavity diameter, which measured 5.3 +/- 0.8 cm in patients with myocarditis versus 4.2 +/- 0.4 cm in controls (P =.001). The degree of left ventricular sphericity in patients with myocarditis, 0.64 +/- 0.08, was significantly greater than that of controls, 0.54 +/- 0.04 (P =.001). When patients were stratified according to left ventricular volume, patients with increased left ventricular volume (>75 mL/m(2)) were associated with a more spherical chamber and lower left ventricular ejection fraction than patients with a more normal left ventricular volume (</=75 mL/m(2)).

CONCLUSIONS

Active myocarditis is associated with early left ventricular remodeling and the development of a spherical chamber. These changes correlate with ventricular dilatation and reduced left ventricular ejection fraction.

Value of the electrocardiogram in localizing the occlusion site in the left anterior descending coronary artery in acute anterior myocardial infarction

OBJECTIVES

The study assessed the value of the electrocardiogram (ECG) as predictor of the left anterior descending coronary artery (LAD) occlusion site in relation to the first septal perforator (S1) and/or the first diagonal branch (D1) in patients with acute anterior myocardial infarction (AMI).

BACKGROUND

In anterior AMI, determination of the exact site of LAD occlusion is important because the more proximal the occlusion the less favorable the prognosis.

METHODS

One hundred patients with a first anterior AMI were included. The ECG showing the most pronounced ST-segment deviation before initiation of reperfusion therapy was evaluated and correlated with the exact LAD occlusion site as determined by coronary angiography.

RESULTS

ST-elevation in lead aVR (ST elevation(aVR)), complete right bundle branch block, ST-depression in lead V5 (ST depression(V5)) and ST elevation(V1) > 2.5 mm strongly predicted LAD occlusion proximal to S1, whereas abnormal Q-waves in V4-6 were associated with occlusion distal to S1 (p = 0.000, p = 0.004, p = 0.009, p = 0.011 and p = 0.031 to 0.005, respectively). Abnormal Q-wave in lead aVL was associated with occlusion proximal to D1, whereas ST depression(aVL) was suggestive of occlusion distal to D1 (p = 0.002 and p = 0.022, respectively). For both the S1 and D1, inferior ST depression > or = 1.0 mm strongly predicted proximal LAD occlusion, whereas absence of inferior ST depression predicted distal occlusion (p < or = 0.002 and p < or = 0.020, respectively).

CONCLUSIONS

In anterior AMI, the ECG is useful to predict the LAD occlusion site in relation to its major side branches.

Medical and surgical therapy for cardiac remodeling

Ventricular remodeling refers to changes in ventricular geometry, volume, mass, and myocellular structure in response to myocardial injury or alteration in loading conditions. Although initially adaptive as a consequence of the initial damage to the myocardium, progressive ventricular remodeling is ultimately a maladaptive process that is associated with significant cardiovascular morbidity and mortality. Treatment with an aim to halt or reverse remodeling with mainly two classes of medications, angiotensin-converting enzyme inhibitors and beta-adrenergic blockers, has been shown to improve the long-term outcome. The role of pharmacologic and surgical therapy in remodeling is evolving and may have an important impact on the development of new directions of therapy for heart failure, myocardial infarction, and hypertension.

Association of Killip class on admission and left ventricular dilatation after myocardial infarction: a closer look into an old clinical classification

BACKGROUND

Early identification of patients in whom left ventricular dilatation is likely to occur may have important therapeutic implications. Thus the purpose of this study was to evaluate the relation between Killip class on admission and subsequent left ventricular dilatation after acute myocardial infarction.

METHODS AND RESULTS

We serially evaluated 129 consecutive patients by two-dimensional and Doppler echocardiography on days 1, 2, 3, and 7, at 3 and 6 weeks, and at 3, 6, and 12 months after infarction. Killip class on admission >1 was found in 29 of 129 (22.5%) patients, and they had significantly higher end-systolic and end-diastolic volume indexes and wall motion score index from day 1 onward compared with patients with Killip class 1, whereas ejection fraction was lower during the follow-up period in these patients. Patients with Killip class >1 showed the progressive increase of end-diastolic (68.2 +/- 2.99 to 88.0 +/- 7.55 ml/m2, p = 0.001) and end-systolic volume indexes (43.9 +/- 2.67 to 56.3 +/- 6. 18 ml/m2, p = 0.004) during the follow-up period, whereas ejection fraction and wall motion score index remained unchanged. In patients with Killip class 1, end-systolic volume index did not change (30.8 +/- 1.06 to 33.8 +/- 2.15 ml/m2, p = 0.064), ejection fraction increased (49.3% +/- 0.99% to 51.8% +/- 1.17%, p = 0.027), and wall motion score index decreased (1.50 +/- 0.03 to 1.35 +/- 0.04, p < 0. 001). End-systolic volume index was the major independent correlate of Killip class, followed by history of diabetes and peak creatine kinase level. No association was found between Doppler indexes of diastolic filling and Killip class on admission.

CONCLUSIONS

Killip class >1 on admission is associated with both acute and long-term left ventricular dilatation. On the other hand, Killip class 1 is associated with favorable left ventricular functional indices, and it appears that left ventricular function in these patients may improve over time. Initial end-systolic volume index but not ejection fraction is the major correlate of Killip class.