Successful Percutaneous Ablation of Ventricular Tachycardia in Congenitally Corrected Transposition of the Great Arteries, a Case Report

Ventricular tachycardia (VT) is rarely recognized in patients with congenitally corrected transposition of the great arteries (CCTGA). We describe a 48-year-old woman with CCTGA, systemic atrioventricular valve replacement for Ebsteinoid malformation of the valve, ventricular dysfunction and ventricular tachycardia related to the previous surgical scar. The patient had successful non-contact mapping and radiofrequency ablation of the offending tachycardia substrate.     

Adjacent organ involvement in Salmonella aortic aneurysms

Salmonella aortic aneurysms occasionally affect adjoining organs. This study reports on 2 elderly men with fatal cases of Salmonella enteritidis involving adjacent organs: aortobronchial fistula from a thoracic aneurysm, and renal involvement from an infrarenal aneurysm. The hope of averting a tragic outcome lies in prompt clinical and radiological recognition followed by effective medical and early surgical interventions.     

Pathophysiology of hereditary hemochromatosis

Hereditary hemochromatosis (HH) encompasses several inherited disorders of iron homeostasis characterized by increased gastrointestinal iron absorption and tissue iron deposition. The most common form of this disorder is HFE-related HH, nearly always caused by homozygosity for the C282Y mutation. A substantial proportion of C282Y homozygotes do not develop clinically significant iron overload, suggesting roles for environmental factors and modifier genes in determining the phenotype. Recent studies have demonstrated that the pathogenesis of nearly all forms of HH involves inappropriately decreased expression of the iron-regulatory hormone hepcidin. Hepcidin serves to decrease the export of iron from reticuloendothelial cells and absorptive enterocytes. Thus, HH patients demonstrate increased iron release from these cell types, elevated circulating iron, and iron deposition in vulnerable tissues. The mechanism by which HFE influences hepcidin expression is an area of current investigation and may offer insights into the phenotypic variability observed in persons with mutations in HFE.     

Effectiveness of anemia and chronic kidney disease as predictors for presence and severity of coronary artery disease in patients undergoing stress myocardial perfusion study

Chronic kidney disease (CKD) and anemia portend a higher risk of cardiac events and mortality. We sought to ascertain whether coronary artery disease (CAD) by myocardial perfusion single-photon emission computed tomography is more common in patients with CKD (glomerular filtration rate < or =60 ml/min/1.73 kg/m(2)) and/or anemia (hemoglobin level < or =13 g/L) and the impact of different degrees of CKD. One thousand five hundred eighty patients (mean age 65 +/- 10 years) underwent gated myocardial perfusion single-photon emission computed tomography and clinical evaluation. Patients were divided into 4 groups (group 1, no anemia/no CKD, n = 800; group 2, anemia/no CKD, n = 195; group 3, CKD/no anemia, n = 332; group 4, anemia/CKD, n = 253). Multivariate logistic regression analysis was undertaken to examine the association of these diagnoses with abnormal myocardial perfusion single-photon emission computed tomogram. Compared with patients with neither diagnosis, an abnormal scan was more common in those with anemia or CKD. Patients with anemia and CKD exhibited more severe CAD (mean summed stress score 6.8 vs 4.7, p <0.01). Established high-risk findings were more prevalent in patients with anemia and/or CKD, including a summed stress score > or =8, transient ischemic dilation, or a left ventricular ejection fraction < or =40% (group 1 28%, group 2 38%, group 3 38%, group 4 48%, all p values <0.01). Patients with moderate CKD demonstrated an increased risk of an abnormal scan (odds ratio 2.66, p <0.0001). After adjustment in multivariate analysis, anemia and CKD each remained predictors for an abnormal scan. The association was stronger in those with the 2 conditions (odds ratio for high-risk scan 1.89, p = 0.0002). In conclusion, in patients with suspected CAD, anemia and CKD are predictors of myocardial perfusion single-photon emission computed tomographic markers for worsened outcomes. The relation was independent of other risk factors, supporting the inclusion of anemia and CKD in global risk assessment for patients with suspected CAD.     

Apolipoproteins A-I and B as predictors of angiographically defined coronary artery disease

Apolipoprotein A-I and B concentrations were measured in 502 patients undergoing diagnostic cardiac catheterization to assess the predictive power of apolipoproteins B and A-I to discriminate between patients with coronary artery disease and those with normal coronary arteries as defined by coronary arteriography. The strength of the associations was compared with that of the associations between traditional risk factors (eg, smoking status, cholesterol levels) and coronary artery disease. The study population consisted of 154 women (mean age, 62.9 years) and 348 men (mean age, 59.6 years). The apolipoprotein A-I concentration averaged (+/- SD) 124 +/- 25 mg/dL and the apolipoprotein B concentration, 98 +/- 24 mg/dL. In all cases, the apolipoprotein measures showed a larger univariate difference between the "normal" (no coronary artery disease) group (66 patients) and the group with coronary artery disease (436 patients) than did the corresponding standard lipoprotein measures. The variable with the strongest association with coronary artery disease was the ratio of apolipoprotein A-I to apolipoprotein B, followed by apolipoprotein B level. These findings were confirmed using logistic regression, adjusting for other coronary artery disease risk factors. Fasting status did not affect apolipoprotein A-I or B concentrations. We conclude that the use of apolipoprotein A-I and B concentrations gives additional information to that supplied by lipoprotein measures to help predict the presence of coronary artery disease. Since traditional lipid measures may be changed by a meal, apolipoproteins A-I and B might be more useful measures when the fasting status of a patient is in question.     

The effects of dobutamine on cardiac sympathetic activity in patients with congestive heart failure

OBJECTIVES: The goal of this work was to study the effects of short-term infusion of dobutamine on efferent cardiac sympathetic activity. BACKGROUND: Increased efferent cardiac sympathetic activity is associated with poor outcomes in the setting of congestive heart failure (CHF). Dobutamine is commonly used in the therapy of decompensated CHF. Dobutamine, through its effects on excitatory beta-receptors, may increase cardiac sympathetic activity. METHODS: Seven patients with normal left ventricular (LV) function and 13 patients with CHF were studied. A radiotracer technique was used to measure cardiac norepinephrine spillover (CANESP) before and during an intravenous infusion of dobutamine titrated to increase the rate of rise in LV peak positive pressure (+dP/dt) by 40%. RESULTS: Systemic arterial pulse pressure increased significantly in response to dobutamine in the normal LV function group (74 +/- 3 mm Hg to 85 +/- 3 mm Hg, p = 0.005) but remained unchanged in the CHF group. Dobutamine caused a significant decrease in LV end-diastolic pressure in the CHF group (14 +/- 2 mm Hg to 11 +/- 2 mm Hg, p = 0.02), an effect not observed in the normal LV group. In the normal LV function group, CANESP did not change in response to dobutamine (75 +/- 22 pmol/min vs. 72 +/- 22 pmol/min, p = NS). In contrast, dobutamine infusion was associated with a significant reduction in CANESP in patients with CHF (199 +/- 43 pmol/min to 128 +/- 30 pmol/min, p < 0.0009). CONCLUSIONS: Dobutamine infusion caused a significant sympatholytic response in patients with CHF. This sympathetic withdrawal response is probably related to reduction of LV filling pressures and/or activation of ventricular mechanoreceptors with dobutamine infusion.