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PubMedDate not supplied

[The ratio of the left ventricular systolic and diastolic functions in patients with hypertrophic cardiomyopathy].

A total of 60 patients with hypertrophic cardiomyopathy (HCMP) and 26 normal subjects were examined. HCMP patients showed increase in maximum ejection rate (ERmax) and shortening of time to reach it, which fact reflects augmentation of myocardial contractility in these patients. Significant alterations were also detectable in left ventricular diastolic function, manifested by a drop in maximum filling rate (FRmax), prolongation of time to reach it, diminution of filling fraction during phase of rapid filling, tendency toward increase of the filling fraction during diastasis phase and atrial systoles, reduction in indices of left ventricular volume compliance. The above alterations had a clear-cut association with the myocardial mass index. Comparative evaluation of left ventricular systolic and diastolic functions in HCMP patients indicated early and marked alterations in diastolic function of the left ventricle, preceding the development of systolic dysfunction, which fact is to be taken into account in choosing suitable medical treatment for HCMP patients.

Adolescent↗
PubMed2006

Anemia, renal dysfunction, and their interaction in patients with chronic heart failure.

Anemia and renal dysfunction (RD) are frequent complications seen in chronic heart failure (HF). However, the prevalence and interaction of these co-morbidities in a representative population of outpatients with chronic HF is poorly described. In this study, it was sought to determine the association between RD and anemia in patients with HF enrolled in a community-based HF program. Nine hundred fifty-five patients with HF due to left ventricular systolic dysfunction were investigated for the prevalence of anemia and its cause and followed for a median of 531 days. Anemia was defined as hemoglobin < 12.0 g/dl in women and < 13.0 g/dl in men. RD was defined as a calculated glomerular filtration rate of < 60 ml/min. The prevalence of anemia was 32%. Fifty-three percent of patients with and 27% of those without anemia had > or = 1 test suggesting hematinic deficiency. The prevalence of RD was 54%. Forty-one percent of patients with and 22% of patients without RD had anemia, with similar proportions associated with iron deficiency in the presence or absence of RD. Anemia and RD independently predicted a worse outcome, and this effect was additive. In conclusion, in outpatients with chronic HF, anemia and RD are common and co-exist but confer independent prognostic information. A deficiency of conventional hematinic factors may cause about 1/3 of anemia in this clinical setting.

Aged↗
PubMedDate not supplied

Coronary stent implantation without lesion predilatation (direct stenting): our experience with this evolving technique.

BACKGROUND: Until recently, conventional intracoronary stent deployment required predilatation of the lesion with a balloon. However, "direct stenting" of the lesion without predilatation offers certain theoretical and practical advantages. We assessed the safety and feasibility of direct stenting in a select group of patients who were likely to benefit most from these advantages, namely, those with acute coronary syndromes. saphenous vein graft lesions, associated renal or left ventricular dysfunction and those requiring multivessel intervention. METHODS AND RESULTS: After direct stenting, intravascular ultrasound was used to assess the adequacy of stent expansion in 51 patients. One hundred and twenty patients with a total of 125 lesions (83.3% males, average age 54.6+/-12.4 years) were enrolled for direct stenting. Of these, 90% of patients had presented with acute coronary syndromes, 21.6% of patients had associated moderate-to-severe left ventricular systolic dysfunction, 6.7% of patients had associated renal dysfunction and 30.8% of patients required multivessel intervention. Angiographically visible thrombus was present in 35.2% of patients. The mean reference diameter of the lesion was 3.18+/-0.32 mm and mean percentage diameter stenosis was 76.4+/-11.2%. Almost all varieties of stents were used (8.8% bare and 91.2% mounted). Procedural success was achieved in 98.3% of patients (98.4% of lesions). In two cases, the lesion had to be predilated prior to stenting. On angiography, the need for postdilatation of the stent was apparent in 29 (23.6%) lesions. In contrast, on intravascular ultrasound evaluation done in 51 lesions after stent deployment, the need for postdilatation to optimize stent expansion was seen in 43 (84.3%) lesions. There was one instance of acute stent thrombosis and two instances of slow-flow phenomenon. There were no deaths, myocardial infarction or need for urgent bypass surgery. CONCLUSIONS: We conclude that direct stenting is feasible and safe in selected groups of patients. Optimization of stent expansion after direct stenting may often require aggressive postdilatation.

Coronary Disease↗
PubMed2001

Management of obesity cardiomyopathy.

Therapy of acute exacerbations of congestive heart failure associated with obesity cardiomyopathy consists of dietary salt restriction, inspired oxygen, diuretics, and angiotensin-converting enzyme inhibitors or, if left ventricular systolic dysfunction is present, hydralazine/isosorbide dinitrate. Digitalis may be indicated in selected cases. These measures may also be useful chronically in association with weight loss. Substantial weight loss is capable of reversing all of the hemodynamic abnormalities associated with obesity except elevation of left ventricular filling pressure. Substantial weight loss may also reduce left ventricular mass and improve left ventricular diastolic filling in those with left ventricular hypertrophy before weight loss. Left ventricular systolic function also improves after weight loss in those with impaired pre-weight-loss systolic function. These beneficial effects of weight loss occur partly because of favorable alterations in left ventricular loading conditions. Substantial weight loss in patients with congestive heart failure associated with obesity cardiomyopathy produces a reversal of many of the clinical manifestations of cardiac decompensation and improves New York Heart Association functional class in most patients.

Cardiomyopathies↗
PubMed1994

Rapid two-stage arterial switch operation. Evaluation of left ventricular systolic mechanics late after an acute pressure overload stimulus in infancy.

BACKGROUND: Banding of the pulmonary artery to induce left ventricular (LV) hypertrophy followed by arterial switch operation (ASO) within 2 weeks has been performed when a primary ASO was considered high risk because of inadequate LV hypertrophy. METHODS AND RESULTS: Potential adverse myocardial effects of the two-stage procedure were examined by comparing outcome in 18 patients after a rapid two-stage ASO with 33 patients after a primary ASO. Regional wall motion was assessed. Echocardiographic and noninvasive pressure data were combined to obtain LV dimension, wall thickness, mass, fractional shortening, rate-corrected mean velocity of shortening, and end-systolic wall stress. Afterload-adjusted velocity of shortening was obtained as a load-independent index of contractility. In the two-stage ASO group, the magnitude and rate of hypertrophy after pulmonary artery banding were measured serially. No wall motion abnormalities were seen in either group. Systolic dysfunction due to higher afterload and lower contractility was observed in the two-stage ASO group. Contractility below the limits of normal was seen in 25% of two-stage ASO compared with 3% of primary ASO; however, symptomatic or progressive LV dysfunction was not observed. There was a significant inverse relation between the peak rate of hypertrophy immediately after banding and contractility at late exam. Lower ejection fraction before and early after pulmonary artery banding correlated with depressed contractility on late examination. CONCLUSIONS: Myocardial contractility is lower after the two-stage ASO than after a primary repair. Severe or progressive dysfunction was not seen. A very high peak rate of hypertrophy and severe LV dysfunction after banding predict a greater reduction in late contractility.

Acute Disease↗
PubMed1998

Coronary collaterals in patients with normal and impaired left ventricular systolic function.

One hundred and twenty consecutive patients with significant coronary artery disease, normal left ventricular systolic function and coronary collaterals (group A) were compared to 120 patients with the same characteristics but with left ventricular systolic dysfunction (group B). No significant differences were found between the two groups on age, hypertension, diabetes mellitus and smoking. The left ventricular end diastolic pressure was 16+/-7 in group A, and 24+/-9 in group B (P<0.01). The number of diseased vessels was similar in both groups. More completely occluded vessels were found in group B (155 vs. 101 in group A). No significant difference was detected between the two groups in the distribution of the diseased vessels. In both groups, the richest collateral supply was to the right coronary artery, followed by collaterals to the left anterior descending. The poorest supply was to the left circumflex. In conclusion, patients with normal and abnormal left ventricular systolic function have similar coronary collateral characteristics.

Aged↗
PubMed2002

Remodeling of small intramyocardial coronary arteries distal to a severe epicardial coronary artery stenosis.

OBJECTIVE: Impaired coronary blood flow (CF) or flow reserve with incomplete and delayed recovery of left ventricular (LV) function after revascularization is common in severe ischemic LV dysfunction. The underlying mechanism is not fully known. We studied structural changes of small intramyocardial coronary arteries (SIMCAs) in a pig model of chronic coronary stenosis, testing the hypothesis that microvascular remodeling develops distally to a severe epicardial coronary artery stenosis. METHODS AND RESULTS: A total of 24 pigs were studied in 3 groups. Left anterior descending coronary stenosis was created to reduce CF by a mean of approximately 30%, producing severe regional systolic dysfunction without infarction. The stenosis was maintained for 7 days in 6 pigs (Group 1) and for 4 weeks in 12 pigs (Group 2). The control group (Group 3) consisted of 6 pigs with the same surgical procedures but without stenosis. The wall thickness (WTa) and lumen (L) diameter of SIMCA were measured, and the ratio of WTa/L and lumen area/total vessel area (% lumen) were calculated. The composition of the arterial wall was studied with cell proliferation markers Ki67 and BrdU. The immediate reduction in CF after the creation of the stenosis was similar in both study groups, but after the first week, CF decreased significantly (P<0.05) when the stenosis was maintained (group 2). The left anterior descending stenosis caused regional LV dysfunction in all pigs (groups 1 and 2). After 4 weeks of stenosis with chronic myocardial hibernation (group 2), but not after 1 week (group 1), WTa and WTa/L increased and L decreased significantly in the chronic hibernating region located distally to the stenosis, compared with both the control (group 3) and the normal region in the same pig. The mean % lumen of SIMCA per pig correlated with the CF reduction (r=0.92, P<0.001) and with myocardial fibrosis (r=0.82, P<0.01) in the 4-week stenosis group. Ki67- and BrdU-positive cells were increased in the wall of SIMCA in Group 1 and 2 compared with the control group (P<0.01 for each). The proliferated cells were stained positively with smooth muscle alpha-actin antibody. CONCLUSION: In the chronic ischemic, hibernating myocardial region distal to a flow-limiting epicardial coronary stenosis, the small intramyocardial coronary arteries undergo remodeling, with an increase in wall thickness and a decrease in lumen. These structural changes may further restrict blood flow to ischemic myocardium and may account for the pathophysiologic impairment of CF or flow reserve after revascularization, which leads to delayed or incomplete recovery of myocardial function.

Animals↗
PubMed2005

Diagnostic accuracy of plasma brain natriuretic peptide and aminoterminal-proBNP in mild heart failure depends on assay and introduction of therapy.

OBJECTIVE: A reliable biochemical marker of left ventricular dysfunction (LVD) could improve diagnostic accuracy. The aim of this study was to compare the correlation of measurements of brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) with different assays. The diagnostic accuracy of the tests in mild heart failure (HF) was estimated before and after the start of therapy. MATERIAL AND METHODS: Doppler echocardiography and measurements of plasma BNP and NT-proBNP were performed in 150 patients. RESULTS: Systolic dysfunction (LV ejection fraction 0.45) was present in 22 patients, and 58 had only abnormalities in LV filling. P-NT-proBNP based on two different assays demonstrated a moderate correlation (r = 0.57, p<0.0001) and a concentration-dependent systematic difference. Excellent correlation (r = 0.95, p<0.0001) was found between BNP and NT-proBNP based on two-site antibody assays, but was moderate between BNP and a one-site antibody NT-proBNP assay (r = 0.58, p<0.0001). Areas under the receiver operating characteristic (ROC) curves (AUCs) were 0.93 (95 % CI, 0.90-0.98) for BNP, 0.95 (0.91-0.99) for NT-proBNP (two-site antibody assay) and 0.77 (0.70-0.85) for the one-site antibody NT-proBNP assay (p = 0.0001). At re-evaluation of LVD at 6 and 12 months, AUCs of BNP were 0.81 (0.74-0.99) and 0.83 (0.76-0.89), respectively, and AUCs of NT-proBNP (two-site) were 0.84 (0.77-0.91) and 0.87 (0.81-0.93), respectively. Using the baseline threshold reduced the sensitivity and specificity of BNP and NT-proBNP measurements. CONCLUSIONS: BNP and NT-proBNP measurements demonstrated assay-dependent correlations. Measurement of p-BNP or p-NT-proBNP by a two-site antibody assay demonstrated potential as an indicator of mild, incident HF, but the applicability of the index tests was limited over time and was likely influenced by therapeutic interventions.

Adult↗
PubMed2005

A comparative serial echocardiographic analysis of cardiac structure and function in rats subjected to pressure or volume overload.

Heart failure is a leading cause of death that is reaching epidemic proportions. It is a clinical syndrome attributable to a multitude of factors that begins with a compensatory response known as hypertrophy, followed by a decompensatory response that eventually results in failure. Heart failure can be triggered when the heart is subjected to extended periods of pathological pressure overload (PO) or volume overload (VO). To date there have been no comparative serial echocardiographic studies outlining the progression of hypertrophy in PO versus VO rats. We hypothesized that PO or VO would induce differential cardiac remodeling leading to contractile dysfunction with subsequent heart failure. To address this hypothesis we used echocardiography to study the serial progression of heart structure and function in rat models of both PO- and VO-induced hypertrophy. PO or VO were induced by performing abdominal aortic banding or aortocaval shunt procedures, respectively, while cardiac structure and function were assessed in both models by M-mode and Doppler echocardiography at key time intervals. PO rats showed progressive wall thickening consistent with concentric hypertrophy, while VO rats showed marked left ventricular dilatation consistent with eccentric hypertrophy. Systolic dysfunction occurred early in VO compared to PO. Diastolic dysfunction was evident in PO, while VO showed signs of enhanced diastolic function. PO and VO induced differential changes in cardiac structure and function during the progression of compensated hypertrophy to decompensated heart failure.

Animals↗
PubMed2004

Global longitudinal strain: a novel index of left ventricular systolic function.

BACKGROUND: Echocardiographic estimation of global left ventricular (LV) function is subjective and time consuming. Our aim was to develop a novel approach for assessment of global LV function from 2-dimensional echocardiographic images METHODS: Novel computer software for tissue tracking was developed and applied as follows: digital loops were acquired from apical 2-, 3-, and 4-chamber views and a line was loosely traced along the LV endocardium at the frame wherein it was best defined. Around this line, the software selected natural acoustic markers moving with the tissue. Automatic frame-by-frame tracking of these markers during the heart cycle yielded a measure of contractility along the selected region of interest. Global longitudinal strain (GLS) and GLS rate (GLSR) were calculated for the entire U-shaped length of LV myocardium (basal, mid, and apical segments of 2 opposite walls in each view). To test this software, computer-derived GLS and GLSR were analyzed by a nonechocardiographer, blinded to the echocardiographic interpretation, in 27 consecutive patients after myocardial infarction (MI) (age 64.4 +/- 12.9 years; 19 men; mean wall-motion score index of 1.79 +/- 0.44) and compared with those obtained in 12 consecutive control patients (age 59.0 +/- 9.7 years; 8 women), with a normal echocardiographic study. RESULTS: GLS and GLSR, averaged from the 3 apical views, differed significantly in patients post-MI compared with control patients (GLS -14.7 +/- 5.1% vs -24.1 +/- 2.9% and GLSR -0.57 +/- 0.21/s vs -1.02 +/- 0.09/s for patients post-MI vs control patients, respectively; both P <.0001). There was a good linear correlation between the wall-motion score index and the GLS and GLSR (R = 0.68 and R = 0.67, respectively; both P <.0001). A cut-off value for GLS of -21% had 92% sensitivity and 89% specificity and a cut-off value for GLSR -0.9/s had 92% sensitivity and 96% specificity for the detection of patients post-MI. CONCLUSIONS: GLS and GLSR are novel indices for assessment of global LV function from 2-dimensional echocardiographic images. Early validation studies with the method are suggestive of high sensitivity and specificity in the detection of LV systolic dysfunction in patients post-MI.

Adult↗
PubMed2005

Clinical outcomes and left ventricular function in diabetic patients with acute myocardial infarction treated by primary coronary angioplasty.

The objective of the present study was to compare left ventricular (LV) function and clinical outcomes in diabetics versus nondiabetics with acute myocardial infarction (AMI) treated by primary coronary angioplasty. A total of 327 consecutive AMI subjects were reperfused by primary coronary angioplasty within 12 hours from onset. Diabetes mellitus (DM) was present in 104 of the 327 patients. LV function was serially determined by left ventriculograms taken in the acute and chronic phases (6 months after onset). (I) The early ST-segment resolution rate was lower in DM patients compared with non-DM patients (59% versus 83%, P < 0.0001). (II) During a 6-month follow-up, the percentages of target vessel revascularization (TVR), coronary aorta bypass grafting (CABG), and cardiac death were higher in the DM patients compared with the non-DM patients (TVR: 29% versus 19%; P < 0.05, CABG: 10% versus 5% ; P < 0.05, cardiac death: 12% versus 4%; P = 0.01). (III) The differences in left ventricular ejection fraction (LVEF) between two stages (delta-LVEF) were significantly lower in the DM patients than the non-DM patients (1 +/- 9% versus 7 +/- 10%, P < 0.0001). (IV) Multivariate analysis identified DM as an independent predictor of cardiac death (Odds ratio 5.5, 95% CI, 1.3-23.7, P < 0.05) and as a sole independent predictor of LVEF deterioration (Odds ratio 5.8, 95% CI, 2.8-11.8, P < 0.001). In patients with AMI treated using primary coronary angioplasty, DM is closely related to left-ventricular systolic dysfunction and a poor patient outcome, including mortality.

Adult↗
PubMed2003

Myocardial hibernation. Clinical and pathological perspectives.

Myocardial hibernation refers to a state of persistent regional contractile ventricular dysfunction, in patients with coronary artery disease that is reversible with revascularization. Identification of hibernating myocardial segments is critical for selecting patients who are most likely to benefit from revascularization procedures. Positron emission tomography, thallium scintigraphy, dobutamine stress echocardiography, myocardial contrast echocardiography and magnetic resonance imaging have been extensively used for detection of viable dysfunctional myocardial segments. Although chronic hypoperfusion and repetitive episodes of brief ischemia may play a role in mediating the changes associated with myocardial hibernation the exact pathogenetic mechanisms are not well understood. The structural alterations found in hibernating myocardial segments involve both the cardio-myocytes and the cardiac interstitium. Depletion of contractile elements, loss of myofilaments, disorganization of myocyte cytoskeletal proteins and alterations in adrenergic receptor density have been reported in segments with reversible systolic dysfunction and may cause segmental hypocontractility. In addition, activation of the inflammatory cascade is noted, leading to cytokine and chemokine induction, leukocyte recruitment, interstitial remodeling and fibrosis. Myocardial hibernation represents a part of the spectrum of ischemic cardiomyopathy, which in the absence of a completed myocardial infarction is a dynamic continuous process ultimately leading to irreversible injury and dysfunction. Understanding of the specific molecular signals involved in the pathogenesis of myocardial hibernation is crucial in order to design strategies preventing irreversible dysfunction.

Animals↗
PubMed2007

Elevated homocysteine is associated with reduced regional left ventricular function: the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: An elevated homocysteine (Hcy) level has been reported to be a risk factor for the development of congestive heart failure in individuals free of myocardial infarction. In this study, we aim to investigate the relationship between Hcy levels and regional left ventricular function in an asymptomatic population. METHOD AND RESULTS: Regional peak systolic midwall circumferential strains were calculated from 1178 tagged magnetic resonance imaging studies in participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Left ventricular regions were defined by coronary territories (left anterior descending, left circumflex, right coronary artery). For the 1178 study participants (66+/-10 years of age, 58% males), the median (interquartile range) of Hcy was 9.1 (9.0 to 9.3). After adjustment for traditional risk factors, race, height, weight, left ventricular end-diastolic mass/volume, serum creatinine, and measures of atherosclerosis, reduced regional myocardial circumferential shortening across sex-specific quartiles of plasma Hcy in the left anterior descending (P=0.038) and left circumflex (P=0.009) regions persisted, which indicated an important association of reduced function with elevated Hcy. Multiple linear regression analyses confirmed that circumferential systolic dysfunction was associated with log transformed Hcy levels in the left anterior descending (P=0.004) and left circumflex (P=0.0002) regions. In the fully adjusted model, the odds ratio for left ventricular strains below the 10th percentile with 1 SD increases in log-transformed Hcy was 1.33 (95% confidence interval, 1.04 to 1.70; P=0.022) for the left anterior descending, 1.28 (95% confidence interval, 1.00 to 1.64; P=0.046) for the left circumflex, and 1.32 (95% confidence interval, 1.03 to 1.69; P=0.025) for the right coronary artery region. CONCLUSIONS: In this asymptomatic population, an elevated Hcy level is associated with reduced regional left ventricular systolic function detected by tagged magnetic resonance imaging.

Aged↗
PubMed2005

Valve replacement in patients with critical aortic stenosis and depressed left ventricular function: predictors of operative risk, left ventricular function recovery, and long term outcome.

OBJECTIVES: To identify predictors of operative and postoperative mortality and of functional reversibility after aortic valve replacement (AVR) in patients with aortic stenosis (AS) and severe left ventricular (LV) systolic dysfunction. METHODS AND RESULTS: Between 1990 and 2000, 155 consecutive patients (mean (SD) age 72 (9) years) in New York Heart Association (NYHA) heart failure functional class III or IV (n = 138) and with LV ejection fraction (LVEF) < or = 30% underwent AVR for critical AS (mean (SD) valve area index 0.35 (0.09) cm2/m2). Thirty day mortality was 12%. NYHA class (3.7 (0.6) v 3.2 (0.7), p = 0.004), cardiothoracic ratio (CTR) (0.63 (0.07) v 0.56 (0.06), p < 0.0001), pulmonary artery systolic pressure (63 (25) v 50 (19) mm Hg, p = 0.03), and prevalence of complete left bundle branch block (22% v 8%, p = 0.03) and of renal insufficiency (p = 0.001) were significantly higher in 18 non-survivors than in 137 survivors. In multivariate analysis, the only independent predictor of operative mortality was a CTR > or = 0.6 (odds ratio (OR) 12.2, 95% confidence interval (CI) 5.4 to 27.4, p = 0.002). The difference between preoperative and immediate postoperative LVEF (early-DeltaEF) was > 10 ejection fraction units (EFU) in 55 survivors. In multivariate analysis, CTR (OR 5.95, 95% CI 3.0 to 11.6, p = 0.006) and mean transaortic gradient (OR 1.05, 95% CI 1.0 to 1.1, p < 0.05) were independent predictors of an early-DeltaEF > 10 EFU. During a mean (SD) follow up of 4.6 (3) years, 50 of 137 (36%) 30 day survivors died, 31 of non-cardiac causes. Diabetes (OR 3.8, 95% CI 2.4 to 6.0, p = 0.003), age > or = 75 years (OR 2.6, 95% CI 2.1 to 4.5, p = 0.004), and early-DeltaEF < or = 10 EFU (OR 0.96, 95% CI 0.94 to 0.97, p = 0.01) were independent predictors of long term mortality. Among 127 survivors, the percentage of patients in NYHA functional class III or IV decreased from 89% preoperatively to 3% at one year. The decrease in functional class was significantly greater in patients with an early-DeltaEF > 10 EFU than patients with an early-DeltaEF < or = 10 EFU (p = 0.02). In addition, the mean (SD) LVEF at one year was 53 (11)% in patients with an early-DeltaEF > 10 EFU and 42 (11)% in patients with early-DeltaEF < or = 10 EFU (p < 0.001). CONCLUSIONS: Despite a relatively high operative mortality, AVR for AS and severely depressed LVEF was beneficial in the majority of patients. Early postoperative recovery of LV function was associated with significantly greater relief of symptoms and longer survival.

Aged↗
PubMed2006

Use of cardiac magnetic resonance imaging in surgical ventricular restoration.

OBJECTIVE: Surgical ventricular restoration (SVR) is a promising modality for treatment of heart failure due to left ventricular systolic dysfunction, particularly that due to ischemic heart disease. The role of MRI in improving diagnosis, operative planning, and follow-up is reviewed to analyze how one examination may define a spectrum of important considerations. METHODS: Proper patient selection and optimal surgical planning relies on accurate assessment of measures of ventricular volume, function, and viability, and of the mechanics of the mitral valve apparatus. A complete preoperative imaging evaluation includes assessment of the left ventricular volume (both systolic and diastolic), regional and global systolic function, viability of the target area for surgical exclusion and of the remote myocardium, determination of the adequacy of the remote myocardium remaining after proposed SVR to support circulatory function, and of the mitral annular dilatation and inter papillary muscle spacing, factors which contribute to functional mitral regurgitation. RESULTS: Cardiac magnetic resonance imaging (MRI) allows a complete evaluation of these quantities: the ventricular systolic and diastolic volumes (and hence ejection fraction) are easily assessed reproducibly and accurately; the regional wall motion of the asynergic area and the remote myocardium can be measured by several quantitative means, including with myocardial tagging, and the presence or absence of nonviable, irreversible scar can be detected with gadolinium-based interstitial contrast agents. Furthermore, an accurate measurement of the mitral annular dimensions and the papillary muscle spacing can be easily performed using cardiac MRI, allowing planning of effective therapy for mitral regurgitation. CONCLUSIONS: The entire imaging study can be performed in less than 1h, making cardiac MRI a truly useful and comprehensive tool in planning SVR, and for subsequently evaluating results.

Heart Failure↗
PubMed1997

Use of left ventricular ejection fraction or wall-motion score index in predicting arrhythmic death in patients following an acute myocardial infarction. The TRACE Study Group.

All-cause mortality and morbidity following an acute myocardial infarction (AMI) are correlated to LV systolic dysfunction. The correlation is closest with mortality and morbidity associated with congestive heart failure (CHF). Prediction of arrhythmic death in patients with AMI relies on the correlation between arrhythmic death and "sudden unexpected death" defined as death within 1 hour of onset of new symptoms. Assessment of late potentials, heart rate variability (HRV), T wave alternans, arrhythmias seen on Holter monitoring or during exercise testing, electrophysiological testing, and baroreceptor assessment have all proven to be useful in the prediction of sudden death even when LV systolic function is known. In selected populations HRV is superior to LV systolic function assessment in predicting sudden death and/or arrhythmic events, and may even predict all-cause mortality with the same precision. Comparisons of other methods with LV function assessment should be interpreted with care because most methods have been evaluated in subgroups of infarct patients with a low risk of death. Results from a large series of high risk patients with AMI (the TRAndolapril Cardiac Evaluation study) have shown that even in patients with severe depressed LV systolic function around one-third of the patients will die suddenly. The current situation is that LV function appears to be the best method of predicting death whereas other methods appear very promising for detecting arrhythmic death in more selected populations. The optimal method for selecting patients at high risk of arrhythmic death has not yet been developed, but a combination of LV function and another method, i.e., HRV, appears promising. This may ensure that the enrolled patients have an increased risk of death and that this risk will be due to arrhythmic events. Patients with LVEF of 10% or less can be excluded as they will most likely not die suddenly.

Arrhythmias, Cardiac↗
PubMed1989

An increase in myocardial beta-adrenoceptors to compensate for postischaemic dysfunction following coronary micro-embolisation in dogs.

This study examined whether beta-adrenoceptors increase in number during recovery from prolonged myocardial stunning and whether they compensate for lack of physiological response to beta-adrenergic stimulation in this abnormality. The left coronary artery was embolished in anaesthetised dogs with non-labelled microspheres (15 +/- 1 micron; 1.2 X 10(6).kg-1 body weight). Haemodynamic studies were performed before (control) and 24 h and 1 week after embolisation, in the conscious state. Myocardial noradrenaline content, plasma catecholamine concentrations and the density of beta-adrenoceptors (Bmax) were also assessed at three study intervals. At 24 h after embolisation, both systolic and diastolic cardiac function was significantly depressed. The inotropic response to isoprenaline was preserved, but the response to forskolin was markedly depressed. One week after embolisation, resting systolic function was restored to control levels and histological examination showed absence of myocardial necrosis. Although plasma noradrenaline concentration had returned to normal, myocardial noradrenaline content had decreased by 36% and the density of beta-adrenoceptors had increased by 48%. Myocardial relaxation was still impaired and the inotropic response to forskolin was also still depressed, whereas the response to isoprenaline was normal. Moreover, the down regulation of the increased beta-adrenoceptors by isoprenaline infusion for 24 h unmasked the latent systolic dysfunction. These results indicate that the density of beta-adrenoceptors increases during the recovery process from prolonged myocardial stunning and that this increase may compensate, at least in part, for impairment of the inotropic mechanism distal to the beta-adrenoceptors.

Animals↗
PubMedDate not supplied

Gated planar technetium 99m-labeled sestamibi myocardial perfusion image inversion for quantitative scintigraphic assessment of left ventricular function.

BACKGROUND: Quantitative assessment of left ventricular systolic performance in conjunction with myocardial perfusion scintigraphy would significantly expand the clinical information obtained from these studies. METHODS AND RESULTS: Left ventricular function was evaluated in 264 patients in whom planar 99mTc-labeled sestamibi myocardial perfusion images were obtained in the best septal left anterior oblique projection. Digital inversion of these perfusion images allows semiautomated evaluation of the left ventricular cavity, with the commonly available edge-detection software designed for equilibrium blood pool imaging. In this study, ejection fractions derived from this technique were compared with those obtained from a myocardial perfusion phantom, first-pass radionuclide angiography, and contrast ventriculography. In vitro validation demonstrated that the myocardial perfusion image inversion ejection fractions correlated linearly with those obtained from a double-chamber phantom (r = 0.999). In vivo, there was good linear correlation between image inversion and first-pass (r = 0.88; image inversion = 0.98 first-pass +0.11), with 95% agreement on the presence or absence of significant left ventricular systolic dysfunction. There was also very good correlation between image inversion and contrast ventriculographic ejection fractions (n = 35; r = 0.85; image inversion = 0.8 contrast +0.05). Intraobserver and interobserver variability of the image inversion ejection fractions was very small (mean difference of 0.4 +/- 0.8 and 2.8 +/- 4.7 units, respectively). CONCLUSION: Gated 99mTc-labeled sestamibi myocardial perfusion image inversion allows evaluation of the dynamics of the left ventricular chamber changes during the cardiac cycle, providing a method for evaluation of systolic function during myocardial perfusion imaging, with highly reproducible results that correlate well with established techniques.

Adult↗