Comparison of degrees of left ventricular dilation within three hours and up to six days after onset of first acute myocardial infarction

Early right ventricular dysfunction after primary percutaneous coronary intervention in anterior versus isolated inferior myocardial infarction assessed by tissue Doppler imaging and speckle tracking echocardiography

This study hypothesized that imaging provides information indicating the right ventricular (RV) involvement after anterior or inferior ST-elevation myocardial infarction (STEMI), beyond standard electrocardiogram (ECG) due to the increasing interest in RV function and assessment techniques. This study aimed to compare RV function between anterior and inferior MI without RV involvement using different echocardiographic modalities. This study included 100 patients with anterior (50 patients) and inferior (50 patients) STEMI, who underwent primary percutaneous coronary intervention (PPCI) and two-dimensional echocardiographic imaging within 24 h after PPCI with RV function analysis by left ventricular (LV) infarct size, LV filling pressure, and RV strain rate. Our primary endpoint was the subclinical RV dysfunction in anterior or inferior MI using tissue Doppler and speckle tracking (STE). The study population included 80 (80%) males and 20 (20%) females. Patients with the anterior STEMI had higher mean creatine kinase-MB (CKMB) and troponin than those with inferior STEMI. This study revealed worse RV dysfunction in patients with anterior than those with inferior STEMI, as reflected by significantly lower RV systolic function, tricuspid annular plane systolic excursion (p ≤ 0.0001), tissue Doppler-derived velocity (p ≤ 0.0001), and STE-derived strain magnitude and rate (p ≤ 0.0001). RV dysfunction occurs in patients without ECG evidence of RV STEMI. RV dysfunction is worse in anterior than inferior MI. Moreover, RV systolic functions were affected by declined LV ejection fraction irrespective of the infarction site, which clinically implies prognostic, treatment, survival rate, and outcome improvement between both conditions. (Trial registration ZU-IRB#:4142/26-12-2017 Registered 26 December 2017, email: IRB_123@medicine.zu.edu.eg).

Engineering the Cellular Microenvironment of Post-infarct Myocardium on a Chip

Myocardial infarctions are one of the most common forms of cardiac injury and death worldwide. Infarctions cause immediate necrosis in a localized region of the myocardium, which is followed by a repair process with inflammatory, proliferative, and maturation phases. This repair process culminates in the formation of scar tissue, which often leads to heart failure in the months or years after the initial injury. In each reparative phase, the infarct microenvironment is characterized by distinct biochemical, physical, and mechanical features, such as inflammatory cytokine production, localized hypoxia, and tissue stiffening, which likely each contribute to physiological and pathological tissue remodeling by mechanisms that are incompletely understood. Traditionally, simplified two-dimensional cell culture systems or animal models have been implemented to elucidate basic pathophysiological mechanisms or predict drug responses following myocardial infarction. However, these conventional approaches offer limited spatiotemporal control over relevant features of the post-infarct cellular microenvironment. To address these gaps, Organ on a Chip models of post-infarct myocardium have recently emerged as new paradigms for dissecting the highly complex, heterogeneous, and dynamic post-infarct microenvironment. In this review, we describe recent Organ on a Chip models of post-infarct myocardium, including their limitations and future opportunities in disease modeling and drug screening.

Emergency department-based 3D echocardiogram use: a case series

Background

Three-dimensional echocardiography (3DE) with real-time volumetric imaging can be a vital modality in clinical practice. Despite its potential, it remains underutilized in the acute care setting.

Case presentation

We present two cases describing the use of 3DE in the emergency department (ED) for acute heart failure (AHF) and discuss the potential benefits of routine use in acute care settings.

Conclusions

Three-dimensional echocardiography offers unique information as it relates to cardiac structure and function, and can be valuable for diagnosis and clinical decision-making in the ED.

Predictive value of early cardiac magnetic resonance imaging functional and geometric indexes for adverse left ventricular remodelling in patients with anterior ST-segment elevation myocardial infarction: A report from the CIRCUS study

BACKGROUND

Postinfarction adverse left ventricular (LV) remodelling is strongly associated with heart failure events. Conicity index, sphericity index and LV global functional index (LVGFI) are new LV remodelling indexes assessed by cardiac magnetic resonance (CMR).

AIM

To assess the predictive value of the new indexes for 1-year adverse LV remodelling in patients with anterior ST-segment elevated myocardial infarction (STEMI).

METHODS

CMR studies were performed in 129 patients with anterior STEMI (58±12 years; 78% men) from the randomized CIRCUS trial (CMR substudy) treated with primary percutaneous coronary intervention and followed for the occurrence of major adverse cardiovascular events (MACE) (death or hospitalization for heart failure). Conicity index, sphericity index, LVGFI, infarct size and microvascular obstruction (MVO) were assessed by CMR performed 5±4 days after coronary reperfusion. Adverse LV remodelling was defined as an increase in LV end-diastolic volume of ≥15% by transthoracic echocardiography at 1 year.

RESULTS

Adverse LV remodelling occurred in 27% of patients at 1 year. Infarct size and MVO were significantly predictive of adverse LV remodelling: odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.05 (P<0.001) and OR 1.12, 95% CI 1.05-1.22 (P<0.001), respectively. Among the newly tested indexes, only LVGFI was significantly predictive of adverse LV remodelling (OR 1.10, 95% CI 1.03-1.16; P=0.001). In multivariable analysis, infarct size remained an independent predictor of adverse LV remodelling at 1 year (OR 1.05, 95% CI 1.02-1.08; P<0.001). LVGFI and infarct size were associated with occurrence of MACE: OR 1.21, 95% CI 1.08-1.37 (P<0.001) and OR 1.02, 95% CI 1.00-1.04 (P=0.018), respectively. Conicity and sphericity indexes were not associated with MACE.

CONCLUSIONS

LVGFI was associated with adverse LV remodelling and MACE 1 year after anterior STEMI.

A Comparison of Three-Dimensional Speckle Tracking Echocardiography Parameters in Predicting Left Ventricular Remodeling

Three-dimensional speckle tracking echocardiography (3D STE) is an emerging noninvasive method for predicting left ventricular remodeling (LVR) after acute myocardial infarction (AMI). Previous studies analyzed the predictive value of 3D STE with traditional models. However, no models that contain comprehensive risk factors were assessed, and there are limited data on the comparison of different 3D STE parameters. In this study, we sought to build a machine learning model for predicting LVR in AMI patients after effective percutaneous coronary intervention (PCI) that contains the majority of the clinical risk factors and compare 3D STE parameters values for LVR prediction. We enrolled 135 first-onset AMI patients (120 males, mean age 54 ± 9 years). All patients went through a 3D STE and a traditional transthoracic echocardiography 24 hours after reperfusion. A second echocardiography was repeated at the three-month follow-up to detect LVR (defined as a 20 percent increase in left ventricular end-diastolic volume). Six models were constructed using 15 risk factors. A receiver operator characteristic curve and four performance measurements were used as evaluation methods. Feature importance was used to compare 3D STE parameters. 26 patients (19.3%) had LVR. Our evaluation showed that RF can best predict LVR with the best AUC of 0.96. 3D GLS was the most valuable 3D STE parameters, followed by GCS, global area strain, and global radial strain (feature importance 0.146, 0.089, 0.087, and 0.069, respectively). To sum up, RF models can accurately predict the LVR after AMI, and 3D GLS was the best 3D STE parameters in predicting the LVR.

Exploring Associations Between Cardiac Structure and Retinal Vascular Geometry

Background

Retinal arteriolar narrowing and venular widening has been widely suggested to be associated with subclinical changes in cardiac structure. The novel retinal vascular geometric indices might reflect more comprehensive information on microvasculature other than vascular caliber alone. However, the association between suboptimal retinal vascular geometry and cardiac structural alteration has not been studied.

Methods and Results

We recruited 50 participants without cardiovascular disease from the Cardiac Aging Study conducted between 2014 and 2016. We performed transthoracic echocardiography imaging to measure cardiac structure indices such as left ventricular internal diameter end diastole index, left ventricular internal diameter end systole index, left ventricular mass index, and left atrial volume index, and retinal imaging to measure retinal vascular geometric indices including branching angle, curvature tortuosity, and fractal dimension. We applied multiple linear regressions to examine associations between indices of cardiac structure and retinal vascular geometry, adjusting for age, sex, body mass index, mean blood pressure, and comorbidity. The average age of all participants was 62.54 years old and slightly more than half were male (27; 54%). Each unit increase in a set of cardiac structure indices was associated with larger retinal arteriolar branching angle (β and 95% CI: for left ventricular internal diameter end systole index, 26.93°; 6.00–47.86; for left ventricular internal diameter end diastole index, 17.86°; 1.61–34.11; for left ventricular mass index, 0.39°; 0.10–0.67; for left atrial volume index, 0.91°; 0.24–1.58).

Conclusions

Adverse retinal arteriolar geometric morphology mirrored suboptimal cardiac structural alteration.

Detection of Left Ventricular Remodeling in Acute ST Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention by Two Dimensional and Three Dimensional Echocardiography

Background

Left ventricular remodeling (LVR) after ST-elevation myocardial infarction (STEMI) harbingers poor prognosis. Three-dimensional echocardiography (3DE) is more accurate than 2 D echo for the assessment of left ventricle (LV) shape. We assessed LV geometry with 3D ECHO 6 months after STEMI in patients who had primary angioplasty.

Materials and Methods

In this prospective study, morphological and functional analysis of LV with 3D ECHO (volumes, LVEF, 3D sphericity index [SI]) was assessed up to 7 days and 6 months in 42 STEMI patients. The LVR was considered for increase >15% of the end diastolic volume of the LV (LVEDV) 6 months after the STEMI, compared to the LVEDV up to 7 days of it.

Results

Sixteen (38%) patients had LVR. 3D Echocardiographic measurements up to 7 days after the acute myocardial infarction (AMI) 1-LVEDV in ventricular remodeling group was 99.8 ± 19.1 ml and in no ventricular remodeling group was 87 ± 18.2 mL (P = 0.037); 2-LVEF was 0.48 ± 0.01 and 51 ± 0.02 (P <.001); 3D-SI was 0.41 ± 0.05 and 31 ± 0.05 (P < 0.001) II-after 6 months: 1-LVEDV in remodeling group was 114.2 ± 19.5 mL and no remodeling group was 94.2 ± 18.6 (P = 0.002); 2-LVEF was 0.58 ± 0.01 and 59 ± .01 (P = 0.003); 3D-sphericity was 0.35 ± 0.05 and 28 ± .05 (P < 0.001).

Conclusion

LVR was observed in 38% of the patients 6 months after AMI. The 3D SI has been associated with occurrence of LVR and can differentiate patients with and without subsequent development of LVR accurately and early on its basis.

Effects of chronic treatment with the new ultra-long-acting β2 -adrenoceptor agonist indacaterol alone or in combination with the β1 -adrenoceptor blocker metoprolol on cardiac remodelling

BACKGROUND AND PURPOSE

The ability of a chronic treatment with indacaterol, a new ultra-long-acting β2 -adrenoceptor agonist, to reverse cardiac remodelling and its effects in combination with metoprolol, a selective β1 -adrenoceptor antagonist, were investigated on myocardial infarction in a rat model of heart failure (HF).

EXPERIMENTAL APPROACH

We investigated the effects of indacaterol and metoprolol, administered alone or in combination, on myocardial histology, β-adrenoceptor-mediated pathways, markers of remodelling and haemodynamic parameters in a rat model of HF. Five groups of rats were assessed: sham-operated rats; HF rats; HF + indacaterol 0.3 mg·kg(-1) ·day(-1) ; HF + metoprolol 100 mg·kg(-1) ·day(-1) ; HF + metoprolol + indacaterol. All pharmacological treatments continued for 15 weeks.

KEY RESULTS

Treatment with either indacaterol or metoprolol significantly reduced the infarct size in HF rats. However, the combination of indacaterol and metoprolol reduced the infarct size even further, reduced both BP and heart rate, reversed the decrease in ejection fraction, normalized left ventricular systolic and diastolic internal diameters, normalized the decreased β1 adrenoceptor mRNA expression as well as cardiac cAMP levels and reduced cardiac GPCR kinase 2 expression, compared with the untreated HF group.

CONCLUSION AND IMPLICATIONS

The results of our study demonstrated an additive interaction between indacaterol and metoprolol in normalizing and reversing cardiac remodelling in our experimental model of HF. The translation of these findings to clinical practice might be of interest, as this combination of drugs could be safer and more effective in patients suffering from HF and COPD.

3D Echo pilot study of geometric left ventricular changes after acute myocardial infarction

BACKGROUND

Left ventricular remodeling (LVR) after AMI characterizes a factor of poor prognosis. There is little information in the literature on the LVR analyzed with three-dimensional echocardiography (3D ECHO).

OBJECTIVE

To analyze, with 3D ECHO, the geometric and volumetric modifications of the left ventricle (VE) six months after AMI in patients subjected to percutaneous primary treatment.

METHODS

Prospective study with 3D ECHO of 21 subjects (16 men, 56 ± 12 years-old), affected by AMI with ST segment elevation. The morphological and functional analysis (LV) with 3D ECHO (volumes, LVEF, 3D sphericity index) was carried out up to seven days and six months after the AMI. The LVR was considered for increase > 15% of the end diastolic volume of the LV (LVEDV) six months after the AMI, compared to the LVEDV up to seven days from the event.

RESULTS

Eight (38%) patients have presented LVR. Echocardiographic measurements (n = 21 patients): I- up to seven days after the AMI: 1- LVEDV: 92.3 ± 22.3 mL; 2- LVEF: 0.51 ± 0.01; 3- sphericity index: 0.38 ± 0.05; II- after six months: 1- LVEDV: 107.3 ± 26.8 mL; 2- LVEF: 0.59 ± 0.01; 3- sphericity index: 0.31 ± 0.05. Correlation coefficient (r) between the sphericity index up to seven days after the AMI and the LVEDV at six months (n = 8) after the AMI: r: 0.74, p = 0.0007; (r) between the sphericity index six months after the AMI and the LVEDV at six months after the AMI: r: 0.85, p < 0.0001.

CONCLUSION

In this series, LVR has been observed in 38% of the patients six months after the AMI. The three-dimensional sphericity index has been associated to the occurrence of LVR.

Polymorphisms of the beta adrenergic receptor predict left ventricular remodeling following acute myocardial infarction

PURPOSE

Prior studies demonstrate an association between specific beta-adrenergic receptor (β-AR) polymorphisms and clinical outcomes in patients with chronic heart failure and following acute coronary syndromes. The underlying mechanism may be due to differences in left ventricular remodeling. This study was undertaken to explore the relationship between LV remodeling after myocardial infarction and polymorphisms in the cardiac β1-AR and β2-AR genes.

METHODS

After first ST-segment elevation myocardial infarction (STEMI), 122 patients on chronic β1 receptor antagonist therapy underwent baseline and 6-month LV volume evaluation. We assessed the relationships between changes in LV volumes and the polymorphisms in β1-AR, β1-Arg389Gly and β1-Ser49Gly, and in β2-AR, β2-Gly16Arg and β2-Gln27Glu.

RESULTS

We found that patients homozygous for the β2-Glu27 variant were 5.2 times more likely to be in the group with the highest end systolic volume (ESV) progression (OR 5.2, 95%CI 1.4-19.0). They were also more likely to have the largest progression of end diastolic volume (EDV) and decrease in LV ejection fraction (LVEF). For those with baseline LV dysfunction, being homozygous for Arg at amino acid position 389 in β1-AR was associated with decreases in ESV (-46 mL, CI -3.1, -88) and EDV (-40 mL, CI -1.1, -79) and an increase in LVEF (11%, CI 0.3, 22).

CONCLUSION

We found that polymorphisms of the β1-AR and β2-AR genes are associated with differential LV remodeling in patients treated with a β1 receptor antagonist following STEMI.

Serial assessment of left ventricular remodeling by measurement of left ventricular torsion using speckle tracking echocardiography in patients with acute myocardial infarction

The relation between remodeling and left ventricular (LV) torsion has not yet been fully investigated. The aim of this study was to determine whether LV torsion assessed by speckle tracking imaging can predict progressive LV dilation after acute myocardial infarction (AMI). From January 2006 through June 2008, 91 patients with AMI who were successfully treated with primary coronary intervention underwent conventional and speckle tracking echocardiographies at initial presentation and 3 days and 6 months after first AMI. Patients were divided into 2 groups based on presence of LV remodeling (increase of LV end-diastolic volume >20%) at 6-month follow-up. LV remodeling developed in 23 patients. At initial presentation, LV end-diastolic volume was not significantly different between the no-remodeling and remodeling groups (91.27 ± 35.68 vs 85.74 ± 28.89 ml, p = 0.51), but LV torsion (2.23 ± 0.67 vs 1.70 ± 0.58°/cm, p <0.05) was significantly decreased in the remodeling group. At 6-month follow-up speckle tracking echocardiography, apical rotation and global torsion in patients with remodeling were 6.7 ± 2.6 (p <0.05) and 1.7 ± 0.7°/cm (p = 0.76 from baseline), respectively, and in patients without remodeling, 8.8 ± 3.4 (p <0.01) and 2.5 ± 0.7°/cm (p <0.01 from baseline), respectively. According to receiver operating characteristic analysis, LV torsion of 1.9°/cm (area under curve 0.79, sensitivity 75%, specificity 78%) at initial presentation was selected as a significant predictor of remodeling. In conclusion, decreased LV torsion assessed by speckle tracking echocardiography may predict late LV remodeling after reperfusion therapy after AMI.

Relation between three-dimensional and two-dimensional echocardiography and biochemical analysis in patients with ST-segment elevation myocardial infarction percutaneously treated

OBJECTIVE

The prognosis of patients with acute myocardial infarction depends on multiple features that can demonstrate myocardial injury degree (such as serum markers of cardiac necrosis), and also on adaptive mechanisms relative to the acute event. The aim of the study was to assess the relation between biochemical and echocardiographic findings from three-dimensional echocardiographic (3D Echo) analysis and echocardiographic two-dimensional (2D Echo) left ventricular ejection fraction in patients with ST-segment elevation acute myocardial infarction, submitted to primary percutaneous treatment.

METHODS

A prospective study with 2D Echo and 3D Echo of 23 patients (17 males, mean age of 57 ± 13 years) with ST-segment elevation acute myocardial infarction, primarily percutaneously treated (stent). Serum cardiac markers (creatine kinase MB, Troponin I and Myoglobin) and serum brain natriuretic peptide were compared to echocardiographic parameters (volumes, left ventricular ejection fraction and ventricular dyssynchrony index). The statistical analysis was performed using Pearson's correlation coefficient, 95% CI, p < 0.05, linear regression equation and Bland & Altman test.

RESULTS

Pearson's correlation coefficient (r)relative to 3D left ventricular ejection fraction: 1- brain natriuretic peptide: r: - 0.7427, p < 0.0001; 2- creatine kinase MB: r: - 0.660, p = 0.001. Left ventricular ejection fraction 2D (r) : 1- brain natriuretic peptide: r: - 0.5478, p = 0.001; 2- creatine kinase MB: r: - 0.4800, p < 0.0277. Other associations were not significant.

CONCLUSIONS

In this series, it was observed better correlation in regard to serum creatine kinase MB, brain natriuretic peptide and 3D Echo left ventricular ejection fraction, when compared to 2D Echo left ventricular ejection fraction.

Maximum persisting single lead ST elevation after primary angioplasty: a good predictor of left ventricular dilatation assessed by magnetic resonance imaging

AIMS

To determine the frequency and predictors of left ventricular dilatation assessed by magnetic resonance imaging among patients with a first acute myocardial infarction treated with successful primary angioplasty and stent.

METHODS AND RESULTS

Cine magnetic resonance imaging and late enhancement imaging were prospectively performed in 42 patients 1 month and more than 1 year after successful early reperfusion of a first acute ST elevation myocardial infarction (age 61 +/- 13 years, 76% men, 55% anterior myocardial infarction, and mean symptom-to-balloon time 199 +/- 130 min). Both at the 1-month and at the 15-month magnetic resonance imaging examinations, 57% of patients had left ventricular dilatation (end-systolic volume indexed > 36 ml/m2, values above the upper 95th percentile based on magnetic resonance imaging reference values for left ventricular size in normal participants). The most accurate predictor of left ventricular dilatation was maximum persisting single lead ST elevation 60 min after reperfusion (area under the curve 0.81, P = 0.001). Maximum single lead ST elevation was significantly and independently associated with larger end-systolic volume indexed (beta = 0.35, P = 0.040) after adjusting for muscle and brain isoenzyme of creatine kinase and echocardiographic wall motion score index.

CONCLUSION

More than half of patients with a first acute myocardial infarction have left ventricular dilatation despite successful primary coronary angioplasty. Maximum persisting single lead ST elevation 60 min after mechanical reperfusion represents a simple tool for predicting left ventricular dilatation.

Association Between A/C1166 Gene Polymorphism of the Angiotensin II Type 1 Receptor and Biventricular Functions in Patients With Acute Myocardial Infarction

BACKGROUND

Although there have been several association studies of angiotensin II type 1 receptor (AT1R, A/C1166) gene polymorphism in clinical endpoints such as myocardial infarction (MI), hypertension, aortic stiffness, and left ventricular mass, the relationship between AT1R polymorphism and biventricular function in acute anterior MI has not been studied before.

METHODS AND RESULTS

The study group comprised 132 consecutive patients who were admitted to the coronary care unit with their first acute anterior MI. Systolic and diastolic diameters, volumes, inflow properties, ejection fraction and myocardial performance index of both ventricles were measured. AT1R polymorphism was determined using polymerase chain reaction amplification. Based on A/C1166 polymorphism of AT1R, the patients were classified into 3 groups: group 1, A/A (n=91) genotype, group 2 A/C (n=28), and group 3 C/C (n=13) genotype. When the left ventricular and right ventricular echocardiographic functions were compared, all parameters of the 3 groups were found to be similar. No difference was detected in either the genotype distribution or allele frequencies between the patients and the controls for AT1R.

CONCLUSIONS

The results suggest that A/C1166 polymorphism of AT1R did not influence the risk of either acute MI or biventricular function after anterior MI.

Scarred myocardium imposes additional burden on remote viable myocardium despite a reduction in the extent of area with late contrast MR enhancement

Magnetic resonance imaging (MRI) can simultaneously detect and quantify myocardial dysfunction and shrinkage in contrast-enhanced areas postinfarction. This ability permits the investigation of our hypothesis that transformation of infracted myocardium to scarred tissue imposes additional burdens on peri-infarcted and remote myocardium. Pigs (n = 8) were subjected to reperfused infarction. Gd-DOTA-enhanced inversion recovery gradient echo sequence (IR-GRE) imaging was performed 3 days and 8 weeks postinfarction. Global and regional left ventricular (LV) function was evaluated by cine MRI. Triphenyltetrazolium chloride (TTC) stain was used to delineate infarction while hematoxylin and eosin (H & E) and Masson's trichrome stains were used to characterize remodeled myocardium. Late contrast-enhanced MRIs showed a decrease in the extent of enhanced areas from 17 +/- 2% at 3 days to13 +/- 1% LV mass at 8 weeks. TTC infarction size was 12 +/- 1% LV mass. Cine MRIs showed expansion in dysfunctional area due to unfavorable remodeling, ischemia, or strain. Ejection fraction was reduced in association with increased end-diastolic and end-systolic volumes. Scarred myocardium contained collagen fibers and remodeled thick-walled vessels embedded in collagen. Sequential MRI showed greater LV dysfunction despite the shrinkage in extent of enhanced areas 2 months postinfarction. The integration of late enhancement and cine MRI incorporates anatomical and functional evaluation of remodeled hearts.

Serological evidence of altered collagen homeostasis reflects early ventricular remodeling following acute myocardial infarction

BACKGROUND

Infarct expansion characterises early ventricular remodeling following myocardial infarction (AMI) and is a product of the balance between collagen degradation and synthesis. Serological markers of collagen turnover may help in predicting those at risk of remodeling. C-propeptide for type-I collagen (PICP) and C-telopeptide for type-I collagen (CITP) are markers of collagen synthesis and degradation, respectively.

METHODS

Fifty-one patients with AMI were recruited and dichotomised by echocardiographic wall motion index (WMI). Sequential measurements of plasma PICP and CITP were correlated to this and other echocardiographic variables of remodeling.

RESULTS

Twenty-three normal WMI, 28 abnormal WMI. Both groups showed increases in PICP and CITP over time. However, mean admission CITP higher in abnormal WMI group, 4.5 vs. 3.1 ng/ml (p<0.05) as was peak, 6.3 vs. 4.8 ng/ml (p<0.05). Conversely, admission PICP was lower in abnormal WMI group 114 vs. 143 ng/ml (p<0.05). Admission CITP correlated with WMI, r=0.53, p<0.001. CITP>3.2 ng/ml (normal mean+2S.D.) had 74% positive predictive value for abnormal WMI, negative predictive value 65%. Admission CITP negatively correlated with mitral deceleration time (Dt), r=-0.38, p=0.01. CITP>3.2 was associated with lower Dt-183 vs. 221 ms, p<0.05.

CONCLUSION

There is serological evidence of sequential increases in both collagen synthesis and degradation following AMI. However, the balance between these differs in patients who undergo remodeling, manifested by abnormal WMI and reduced Dt, compared to those with no evidence. They have relatively increased degradation and reduced synthesis, favouring net collagen breakdown. These changes occur early with evidence of increased breakdown on admission predicting early remodeling and support the role of serological markers to identify patients at risk of this.

Angiotensin II receptor blockade and ventricular remodelling

Cardiac remodelling is the expression of molecular, cellular and interstitial changes in response to cardiac injury, manifesting as adverse alterations in the size, shape and function of the ventricle. Several clinical studies have documented significant elevations in the levels of renin, angiotensin II (Ang II) and aldosterone attending acute myocardial infarction and/or congestive heart failure. Similar to catecholamines, markedly elevated activity of the renin-angiotensin-aldosterone system (RAAS) is associated with poor prognosis. The effects of Ang II upon cardiac tissue are related to two primary receptors, Ang II type 1 (AT1) and Ang II type 2 (AT2). The AT1-receptor appears to mediate many of the deleterious effects of chronic RAAS activity, while the AT2-receptor is increasingly shown to have potential cardioprotective effects. Attenuating the deleterious effects of sustained Ang II stimulation can be achieved by direct inhibition of angiotensin- converting enzyme (ACE) and/or direct antagonism of AT receptors. ACE inhibition reduces left ventricular (LV) volumes, retards the progression of LV dilatation and hypertrophy and increases systolic function in systolic dysfunction. By blocking at the receptor level, Ang II receptor blockers (ARBs) provide an alternative and more direct approach to inhibiting the effects of Ang II; however, data relating to their effects upon ventricular remodelling, whether used in isolation or in combination with ACE inhibitors (ACE-Is), are less convincing. Data arising from several recent clinical trials suggest that simultaneous use of ACE-Is and ARBs maybe of more benefit in attenuating ventricular remodelling than either agent alone.

Remodelage précoce du ventricule gauche après un accident coronarien aigu

Ventricular remodelling following acute coronary syndromes is both complex and multiform. It is due to the response of the myocardium to the different agressions associated with these syndromes, in particular the ischemia and necrosis downstream of the occluded artery. We must not however neglect the role of the remodelling of the lesions resulting from spontaneous reperfusion or provoked by the cells and tissues associated with coronary microcirculation embolisms and the no-reflow phenomenon. Acute post-infarct remodelling is dominated by early ventricular dilatation which largely affects late prognosis, necrosis elimination and its replacement by a fibrotic scar in parallel with a compensatory hypertrophy of the non-infarcted myocardium. The diverse cellular and molecular components of this remodelling are increasingly well-known, allowing us to better explain the beneficial effects of the currently available medications and providing us with new potential therapeutic targets. A grading of this knowledge associated with the identification of new risk factors and early therapeutic interventions should help us to further limit the deleterious aspects of this remodelling in the goal of preventing, or at least delaying, the devolution towards heart failure.

Index of myocardial performance after early phase of myocardial infarction in relation to its location

To define the degree of heart derangement in recent myocardial infarction (MI) occurring in different wall locations of myocardium, we echocardiographically evaluated left ventricular volumes, ejection fraction, wall-motion score index, isovolumetric contraction and relaxation time, ejection time, and index of myocardial performance in 74 patients with MI. Participants were chosen among the patients with MI of comparable extent and interesting unlike zones of myocardial walls. Mean values of evaluated left ventricular end-diastolic and end-systolic volumes and ejection fraction were nearly alike in all patients, whereas wall-motion score index and index of myocardial performance were cleary prolonged in those with anterior MI in comparison with the values recorded in patients with lateral or inferior MI. The mean values of isovolumetric contraction and relaxation time suggest that a prevalent systolic dysfunction is present in the early phase of MI. In addition, the different index of myocardial performance prolongation in MI otherwise located suggests evidence that MI located in the anterior wall has more serious effect than lateral or inferior MI.

Early association of electrocardiogram alteration with infarct size and cardiac function after myocardial infarction

OBJECTIVE

Myocardial infarction (MI) is the main cause of heart failure, but the relationship between the extent of MI and cardiac function has not been clearly determined. The present study was undertaken to investigate early changes in the electrocardiogram associated with infarct size and cardiac function after MI.

METHODS

MI was induced by ligating the left anterior descending coronary artery in rats. Electrocardiograms, echocardiographs and hemodynamic parameters were assessed and myocardial infarct size was measured from mid-transverse sections stained with Masson's trichrome.

RESULTS

The sum of pathological Q wave amplitudes was strongly correlated with myocardial infarct size (r = 0.920, P < 0.0001), left ventricular ejection fraction (r = -0.868, P < 0.0001) and left ventricular end diastolic pressure (r = 0.835, P < 0.0004). Furthermore, there was close relationship between MI size and cardiac function as assessed by left ventricular ejection fraction (r = -0.913, P < 0.0001) and left ventricular end diastolic pressure (r = 0.893, P < 0.0001).

CONCLUSION

The sum of pathological Q wave amplitudes after MI can be used to estimate the extent of MI as well as cardiac function.

Ventricular remodeling

Ventricular remodeling is an extremely complicated process that is not well understood. There seem to be multiple feedback loops that respond to mechanical events as well as to neurohormonal stimulation, cytokine release, and other, yet unidentified, agents. The progression of ventricular remodeling after the index event includes: Myocyte slippage and thinning of infarct area, chamber dilatation. Fibrosis and scar formation. Collagen strut dissolution and excessive accumulation of interstitial matrix. Increased wall stress. Myocyte hypertrophy. Neurohormonal activation. Cytokine release. Ongoing myocyte hypertrophy. Cell apoptosis and necrosis. Continued deterioration of cardiac function. It is impossible to place the sequence of events in order, because the multiple feedback systems create a complex interactive process. A basic awareness of the pathophysiology of ventricular remodeling can aid in understanding current and future treatments for heart failure. It is clear that therapeutic interventions solely aimed at improving cardiac pump function do not slow the progression of heart failure or reduce mortality. Drugs that block the neuroendocrine contribution to the remodeling process have been shown to have a greater impact. Current therapies with angiotensin-converting enzyme inhibition, beta blockade, and aldosterone antagonism are associated with significant reductions in morbidity and mortality in heart failure. Other therapeutic strategies suggested by knowledge of remodeling mechanisms, such as drugs to block cytokines, endothelins, and MMPs, may offer further benefit to patients with heart failure in the future.

Regional wall stress predicts ventricular remodeling after anteroseptal myocardial infarction in the Healing and Early Afterload Reducing Trial (HEART): an echocardiography-based structural analysis

BACKGROUND

Increased left ventricular (LV) wall stress after myocardial infarction (MI) has been implicated in LV remodeling. However, the relationship between LV wall stress and LV remodeling is incompletely defined.

METHOD

We prospectively studied the relationship between regional wall stress and LV remodeling by application of the finite element method to end-systolic LV models from patients enrolled in the Healing and Early Afterload Reducing Therapy (HEART) Trial. Individual LV models were constructed from orthogonal apical echocardiographic views obtained at day 14 after anteroseptal MI in 64 patients. Of these, 31 patients received low-dose (0.625 mg) ramipril and 33 patients received full-dose (10 mg) ramipril. LV wall stress was calculated by the finite element method and correlated with change in LV volume from day 14 to day 90 after MI.

RESULTS

Among all patients, increases in apical regional wall stress were associated with LV volume changes (P -trend =.015). The relationship between apical regional wall stress and change in LV volume was strongest in the low-dose ramipril group (r = 0.53, P =.002) and remained significant after adjustment for end-diastolic volume, infarct size, ejection fraction, and systolic blood pressure yet was attenuated in the full-dose ramipril group.

CONCLUSIONS

Apical regional wall stress is an independent predictor of subsequent LV remodeling after MI. The relationship between increased apical wall stress and LV dilatation appears to be attenuated by full-dose angiotensin-converting enzyme inhibition.

Cardiac remodeling--concepts and clinical implications: a consensus paper from an international forum on cardiac remodeling. Behalf of an International Forum on Cardiac Remodeling

Cardiac remodeling is generally accepted as a determinant of the clinical course of heart failure (HF). Defined as genome expression resulting in molecular, cellular and interstitial changes and manifested clinically as changes in size, shape and function of the heart resulting from cardiac load or injury, cardiac remodeling is influenced by hemodynamic load, neurohormonal activation and other factors still under investigation. Although patients with major remodeling demonstrate progressive worsening of cardiac function, slowing or reversing remodeling has only recently become a goal of HF therapy. Mechanisms other than remodeling can also influence the course of heart disease, and disease progression may occur in other ways in the absence of cardiac remodeling. Left ventricular end-diastolic and end-systolic volume and ejection fraction data provide support for the beneficial effects of therapeutic agents such as angiotensin-converting enzyme (ACE) inhibitors and beta-adrenergic blocking agents on the remodeling process. These agents also provide benefits in terms of morbidity and mortality. Although measurement of ejection fraction can reliably guide initiation of treatment in HF, opinions differ regarding the value of ejection fraction data in guiding ongoing therapy. The role of echocardiography or radionuclide imaging in the management and monitoring of HF is as yet unclear. To fully appreciate the potential benefits of HF therapies, clinicians should understand the relationship between remodeling and HF progression. Their patients may then, in turn, acquire an improved understanding of their disease and the treatments they are given.

Serial changes and prognostic implications of a Doppler-derived index of combined left ventricular systolic and diastolic myocardial performance in acute myocardial infarction

The purpose of this study was to investigate the serial changes and prognostic value of a nongeometric Doppler-derived index of myocardial function that combines systolic and diastolic time intervals of the left ventricle in acute myocardial infarction (AMI). The Doppler index was measured in 60 consecutive patients with AMI and in 30 patients admitted to hospital with suspected but disproved AMI who served as controls. The patients were studied at days 1, 5, 90, and 360 after arrival in the coronary care unit. The index was defined as the sum of isovolumetric contraction time, and isovolumetric relaxation time divided by ejection time was measured from mitral inflow and left ventricular outflow Doppler velocity profiles. The index was significantly higher in patients with AMI than in control subjects at days 1 and 360 (day 1, 0.58 +/- 0.09 vs 0.41 +/- 0.08, p <0.0001; day 360, 0.50 +/- 0.09 vs 0.39 +/- 0.07, p <0.01, respectively). The index decreased significantly in patients with AMI during follow-up (p <0.01). The index was significantly higher in patients who developed congestive heart failure or died compared with survivors who were free of congestive heart failure (day 1, 0.63 +/- 0.10 vs 0.53 +/- 0.10, p <0.01; day 360, 0.56 +/- 0.08 vs 0.48 +/- 0.10, p <0.01, respectively). During 20.2 +/- 8.5 months' follow-up, 10 patients died of cardiac causes and 13 developed congestive heart failure. Univariate analyses demonstrated that the Doppler index > or =0.60 (chi-square 8.3, p <0.0001), deceleration time < or =140 ms (chi-square 8.5, p <0.0001), ejection fraction < or =0.40% (chi-square 3.3, p <0.005), anterior wall AMI (chi-square 3.2, p <0.01), and age (chi-square 1.06/ year increase, p <0.01) were significant predictors of outcome. Multivariate stepwise analysis showed that the index < or =0.60 (chi-square 3.4, p <0.05), deceleration time < or =140 ms (chi-square 4.2, p <0.02), and age (chi-square 1.06/year increase, p <0.02) were independent predictors of outcome. The Doppler index reflects severity of left ventricular function and has incremental prognostic value in patients with AMI.

Heterogeneous fate of perfusion and contraction after anterior wall acute myocardial infarction and effects on left ventricular remodeling

After acute myocardial infarction, patency of infarct vessel and extent of left venticular (LV) dysfunction are major determinants of ventricular remodeling. Spontaneous, delayed reperfusion in the infarct zone occurs in a sizeable number of patients well after the subacute phase. The aim of this study was to determine the relation between the occurrence of this spontaneous, delayed reperfusion and LV remodeling. In 84 patients, resting LV volumes, topography, regional function, and perfusion were quantitatively evaluated by 2-dimensional echocardiography and sestamibi tomography 5 weeks (study 1) and 7 months (study 2) after anterior Q-wave infarction. At study 2, LV end-diastolic volume increased by > 15% in 17 patients (20%, LV remodeling); they had already had at study 1 significantly larger LV volumes, more severe hypoperfusion and wall motion abnormalities, and greater regional dilation than patients with stable LV volumes. Delayed reperfusion occurred in 8 of 17 patients with and in 42 of 67 patients without LV remodeling (47% vs 63%; p=NS). At study 2, LV regional dilation and end-diastolic volumes were stable in patients with, but increased in patients without, spontaneous reperfusion (from 25+/-24% to 29+/-26% at study 2 [p<0.05] and from 65+/-14 to 68+/-18 ml/m2 [p <0.05]). At multivariate analysis, however, regional ventricular dilation at study 1 was the sole predictor of further LV remodeling. Thus, after acute myocardial infarction, spontaneous reperfusion occurring after 5 weeks plays only a minor role in influencing LV remodeling. Benefits from delayed reperfusion seem limited to patients with preserved LV volumes; patients with an enlarged left ventricle 5 weeks after acute infarction are prone to further LV remodeling, irrespective of delayed reperfusion.