The Journal of Tehran University Heart Center
Volume:4 Issue: 2, Apr 2009

The worldwide prevalence of insulin resistant states such as the metabolic syndrome has grown rapidly over the past few decades. The metabolic syndrome is a constellation of common metabolic disorders that promote the development of atherosclerosis and cardiovascular disease. Studies in both human and animal models suggest that hepatic inflammation and insulin resistance are key initiating factors in the development of the metabolic syndrome. Chronic inflammation is known to be associated with visceral obesity and is characterized by production of abnormal adipokines and cytokines such as tumor necrosis factor a, interleukin-1 (IL-1), IL-6, leptin, and resistin. These factors inhibit insulin signaling in the liver (hepatocytes) by activating suppressors of cytokine signalling proteins; several kinases such as c-Jun N-terminal kinases, IKK-β, and Protein kinase C; and protein tyrosine phosphatase 1B, that in turn impair insulin signaling at insulin receptor and insulin receptor substrate level. Hepatic insulin resistance in turn causes impaired suppression of glucose production by insulin in hepatocytes leading to hyperglycemia, induction of very low density lipoprotein production, and de novo lipogenesis. Increased production of C-reactive protein (CRP) and plasminogen activator inhibitor-1, both markers of an inflammatory state, is also observed in insulin resistance. All of the above metabolic abnormalities can directly or indirectly promote atherosclerosis. In particular, hyperglycemia induces endothelial dysfunction, cellular proliferation, changes in extracellular matrix conformation, and impairment of low density lipoproteins (LDL)-receptor-mediated lipoprotein uptake. Small dense LDLs have higher affinity to the intimal proteoglycans, leading to the penetration of more LDL particles into the arterial wall. CRP can also accelerate atherosclerosis by increasing the expression of PAI-1 and adhesion molecules in endothelial cells, inhibition of nitric oxide formation, and increasing LDL uptake into macrophages. In summary, hepatic insulin resistance is a critical early event that underlies the development of the metabolic syndrome and progression to atherosclerosis and cardiovascular disease.

Echocardiography is the most common test used for the evaluation of aortic regurgitation (AR). However, the role of echocardiography as an available and inexpensive method in the quantification of AR by the left ventricle to right ventricle stroke volume ratio (LV/RV SV ratio) has not been completely investigated. Between June 2005 and December 2007, 132 consecutive patients with AR (mean age: 44.7±14.6 years, 52.3% male) were enrolled in the study. All the patients underwent echocardiography; and aortography, if indicated, was performed as well. Fifty-two percent of the patients had severe AR. There was almost a perfect agreement between echocardiography and cardiac catheterization in determining the severity of AR (Kappa=0.81). Associated valvular disease was found in 81.8% of the patients, the most common disease being mitral regurgitation (61%). The results of our bivariate and multivariate analyses showed a significant relation between the LV/RV SV ratio and the AR severity via either echocardiography or cardiac catheterization (both P=0.001). The receiver operating characteristic (ROC) curve analysis showed that the LV/RV SV ratio was very accurate in the detection of severe AR utilizing cardiac catheterization as the gold standard (AUC=0.71). The cut point value of the LV/RV SV ratio ≤1.5 had a sensitivity of 56% and specificity of 75% for the differentiation of non-severe from severe AR. Our study demonstrated that the LV/RV SV ratio was a simple and reliable method for the assessment of the severity of AR. This method is more accurate in the absence of a significant involvement of the other valves.

Pulse wave velocity (PWV) is widely used for estimating the stiffness of an artery. Various invasive and non-invasive methods have been developed to determine PWV over the years. In the present research, the non-invasive estimation of the PWV of large arteries was used as an index for arterial stiffness. A dynamic model based on the Navier-Stokes equations coupled to elasticity equations was introduced for the PWV in arteries with elastic walls. This system of equations was completed by clinical information obtained from the Doppler ultrasound images of the carotid artery of 40 healthy male volunteers. For this purpose, the Doppler ultrasound images were recorded and saved in a computer; and subsequently center-line blood velocity, arterial wall thickness, and arterial radius were measured by offline processing. The results from the analytic solution of the completed equations showed that the mean value of PWV for the group of healthy volunteers was 2.35 m/s when the mean arterial radius was used as the neutral radius and 5.00 m/s when the end-diastole radius was used as the neutral radius. It is noteworthy that the latter value closely complies with that reported by other researchers. By applying this method, a non-invasive clinical and local evaluation of the common carotid artery stiffness via a Doppler ultrasound measurement will be possible.

Studies on the prognosis of ST elevation myocardial infarction (STEMI) versus non-ST elevation myocardial infarction (non-STEMI) have shown different results. The present study was designed to compare the early outcome and left ventricular systolic function of patients with ST and non-ST elevation myocardial infarction. The patients'' information was derived from 10,065 consecutive patients hospitalized in Tehran Heart Center with acute MI (2007 patients with STEMI and 8058 with non-STEMI). The baseline clinical characteristics, post-MI complications, left ventricular systolic functions, and 30-day mortality rates were compared. A history of current cigarette smoking, opium addiction, and brain stroke was more frequent in the STEMI patients, whereas hyperlipidemia, hypertension, and obesity were found more in the non-STEMI group. Ejection fraction was higher in the non-STEMI patients than that in the STEMI group, and anterior wall infarction was detected more frequently in the STEMI cases. A history of coronary artery bypass grafting and also percutaneous coronary intervention was observed more in the non-STEMI group. Amongst the in-hospital complications, ventricular arrhythmias (1.4 vs. 0.5, P<0.001) and pulmonary edema (0.4 vs. 0.1, P=0.002) were more prevalent in the STEMI cases. The 30-day mortality rate in the STEMI group was higher than that in the non-STEMI group (5.5 vs. 2.4, P<0.001). Early mortality in both groups was dependant on advanced age, diabetes mellitus, post-MI bradycardia, and atrioventricular block. Also, female gender and pulmonary edema in the STEMI group and family history of MI in the non-STEMI patients could predict 30-day mortality. There were several differences in the baseline characteristics and early outcome between the two types of STEMI and non-STEMI. The 30-day mortality rate was higher in the STEMI group than that in the non-STEMI group.

Pulmonary arterial hypertension is a complication of most congenital heart diseases. We sought to assess the effect of sildenafil on patients suffering from pulmonary arterial hypertension in association with congenital heart disease on the basis of clinical and echocardiographic parameters and compare the catheterization and treatment results so as to evaluate the predictive value of sildenafil on the operability of patients. After primary echocardiography, 21 patients were selected for the final study with a diagnosis of moderate-to-large ventricular septal defect and pulmonary artery hypertension. They were divided into 3 age groups: younger than one year, 1 to 2 years, and older than 2 years. Before and one hour after the consumption of sildenafil, the patients had their oxygen saturation and blood pressure measured. Additionally, the patients underwent echocardiography and cardiac catheterization. The patients’ operability was determined on the basis of their clinical condition and their response to oxygen inhalation in the catheterization room. Finally, the results of the drug response and final treatment were analyzed statistically. The 21 patients, who had ventricular septal defect and pulmonary arterial hypertension, were comprised of 8 (38%) boys and 13 (62%) girls. The patients aged from 2.5 to 204 months (mean 30 months). It was clear that the younger patients had a more positive response to the drug. All the patients who had a positive response to the drug were considered operable after catheterization and all of them had a positive response to treatment. There was no significant correlation between operable/inoperable conditions and response to treatment (P value=0.262), while there was a very significant correlation between response to treatment and response to drug (P value=0.005). According to the results of this study and given the low cost and availability of sildenafil and its oral consumability on the one hand and the availability and non-invasiveness of echocardiography on the other, it seems that sildenafil is useful in determining the pulmonary vascular bed reactivity via echocardiographic parameters and facilitating the decision-making process for surgery in patients with pulmonary arterial hypertension and congenital heart diseases.

Brain type natriuretic peptide (BNP) is a cardiac hormone that is secreted mainly by the ventricles in response to volume expansion and pressure load. It can predict post-operative complications after heart surgery in adults. We sought to investigate the prognostic value of BNP in children after heart surgery. We measured the BNP serum levels in 96 children with congenital heart diseases before, immediately after, and 12 hours after open heart surgery. We studied the ability of the post-operative BNP serum level variations to predict mortality and morbidity in children. In total, 96 patients, comprising 40 (41.7%) females and 56 (58.3%) males with a mean age of 4.1 years (range: 1 month to 17 years), with various congenital heart diseases were studied. The rise in the serum BNP level 12 hours post surgery was directly related to mortality before discharge from hospital (P value=0.004), congestive heart failure after surgery (P value<0.001), patients'' cyanosis (P value=0.045), duration of ICU stay (r=0.342, P value=0.004), and post-operative need for inotropic drugs (P value<0.001). The rise in the BNP serum level 12 hours after heart surgery is a good marker for predicting mortality, morbidity, and early diagnosis of heart failure in children.

Cardiac resynchronization therapy (CRT) is an effective treatment for patients with moderate to severe heart failure. However, 20-30% of patients remain non-responders to CRT. We sought to identify which patients benefit the most from CRT in regard to the etiology of heart failure. Eighty-three consecutive patients (62 men) who had a biventricular pacemaker inserted at Tehran Heart Center between May 2004 and March 2007 were evaluated retrospectively. The inclusion criteria were comprised of New York Heart Association (NYHA) class III or IV, left ventricular ejection fraction<35%, and QRS>120ms. After 6 months, response was defined as being alive, no hospitalization for cardiac decompensation, and an improvement in NYHA class>1 grade. After 6 months, 60 patients out of the 83 patients were responders. Amongst the 83 patients, 48 had ischemic cardiomyopathy and 35 had non-ischemic cardiomyopathy. A cross-tabulation of response versus etiology showed no significant difference between ischemic versus non-ischemic cardiomyopathy with regard to response to CRT (P=0.322). According to our study, there was no difference in response to CRT between ischemic versus non-ischemic cardiomyopathy at six months’ follow-up.

Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

Hydatid disease, caused by echinococcus granulosus, is a common infectious disease in endemic areas such as Southern Europe and the Middle East. The incidence of this disease, however, is on the increase in Northern Europe due to the migration of labor and also tourism. We report a case of the hydatid cyst of the mediastinum, the diagnosis of which was established by the hemagglutinin test and echocardiography and confirmed by histological examinations. The cyst was totally removed during surgery on beating heart. The patient presented herein demonstrates that the mediastinal and cardiac involvement in hydatid disease could manifest in children with fast growth and rupture.