An unusual case of infective endocarditis involving a right coronary artery to superior vena cava fistula.

Coronary artery fistulas (CAFs) are rare and mostly congenital anomalous connections between a coronary artery and a cardiac chamber or great vessel. Most CAFs are small, asymptomatic, and found incidentally during cardiac imaging. However, they can lead to serious complications including myocardial infarction, congestive heart failure, arrhythmias, or fistula rupture. CAFs have been associated with infective endocarditis, but to our knowledge, this complication has never been reported involving an isolated CAF to an otherwise anatomically normal great vessel. We report the first case of this complication in a 49-year-old man with a presumed streptococcus vegetation found within an isolated large, tortuous CAF connecting the right coronary artery to the superior vena cava. After completing antibiotic treatment, transcatheter closure of the CAF was performed. Since then, the patient has remained symptom-free. This case demonstrates that CAF closure is feasible following CAF-associated endocarditis, and that closure may represent a viable strategy for reducing risk of recurrent infection.

Can low-carbohydrate diets be recommended for reducing cardiovascular risk?

PURPOSE OF REVIEW: This review provides a rationale for implementing carbohydrate restriction as a dietary therapy to improve biomarkers of cardiovascular health and suggests that this will require a paradigm shift away from what is currently promulgated as a 'heart-healthy' diet. RECENT FINDINGS: Type 2 diabetes mellitus (T2DM), metabolic syndrome, and related co-morbidities are major risk factors for cardiovascular disease (CVD). Ideally, then, a diet intended to support cardiovascular health should be one that improves or reverses these underlying risk factors. Carbohydrate restriction is effective for this purpose as well as for favorably impacting atherogenic dyslipidemia. Recent consensus reports from select national organizations have endorsed low-carbohydrate diets for improving glycemia and cardiovascular risk. Reluctance among public health organizations and some clinicians to more widely promote this therapeutic nutritional approach is driven primarily by the increase in serum low-density lipoprotein cholesterol (LDL-C) observed in a proportion of individuals who adopt a low-carbohydrate diet. Here we explore the rationale for using carbohydrate restriction to improve cardiovascular health by way of favorably impacting T2DM and insulin resistance, and why this salutary effect outweighs the potential adverse effects of an increase in serum LDL-C. SUMMARY: Carbohydrate restriction is a logical foundation for a dietary intervention intended to reduce CVD risk, particularly among individuals with T2DM or metabolic syndrome.

Aortic dissection and pericardial tamponade causing compression of the pulmonary arteries in a patient with prior cardiac surgery.

A patient with prior aortic valve surgery presented with aortic dissection and pericardial tamponade, with subsequent compression of the pulmonary arteries. While both expanding pericardial effusions and aortic dissections have been reported to cause compression of other adjacent structures, compression of the pulmonary artery vasculature in a patient with prior cardiac surgery has never been described. In this case report, we highlight this situation, which may have occurred because of alterations in the pericardial and mediastinal spaces.

Frequency and cause of cardiac troponin T elevation in chronic hemodialysis patients from study of cardiovascular magnetic resonance.

Cardiac troponin T level predicts a gradient risk for death in patients using hemodialysis. We used cardiovascular magnetic resonance (CMR) to determine whether an asymptomatic increase of troponin T in patients using hemodialysis is associated with subclinical myocardial infarction (MI). Twenty-six patients using long-term hemodialysis (49 +/- 12 years of age, 19 men, 8 diabetics) with left ventricular (LV) ejection fraction >40% and no known coronary artery disease were selected based on a low-risk troponin T level /=0.07 ng/ml (median 0.15, interquartile range 0.09 to 0.19, n = 13). All underwent CMR imaging for LV mass and for MI by late gadolinium enhancement. Between high- and low-risk patients using hemodialysis, there were no differences in age, gender, ethnicity, or diabetes mellitus. Of the high-risk patients, 3 (23%, 95% confidence interval [CI] 5 to 54) had MI by late gadolinium enhancement versus 0 (0%, 95% CI 0 to 25) low-risk patients (p = 0.22). A diffuse, midwall late gadolinium enhancement pattern was seen in 1 high-risk patient (8%) versus 0 low-risk patient (0%, 95% CI 0 to 25, p = 0.97). Height-adjusted LV mass and LV hypertrophy were not significantly different between high-risk (62 +/- 26 g/m(2.7), LV hypertrophy, n = 7, 54%) and low-risk (54 +/- 20 g/m(2.7), LV hypertrophy, n = 5, 39%) patients (p = 0.37 for LV mass, p = 0.69 for LV hypertrophy). In conclusion, MI detected by CMR is present in few patients on hemodialysis with high troponin T levels and absent in the setting of very low troponin T levels, suggesting that additional myocardial pathologies cause increased troponin T in patients using hemodialysis.

Echocardiography in the cardiac transplant recipient.

Despite the widespread use of echocardiography in the cardiac allograft recipient, the clinical usefulness of this practice is not well defined. In this article, the authors review the spectrum of echocardiographic findings in the adult heart transplant patient. Appreciation of typical alterations from "normal" allows the transplant physician to identify clinically significant changes and to avoid unnecessary invasive procedures based on misinterpretation of these differences. Though abnormalities of systolic and diastolic function correlate with episodes of acute rejection, the primary diagnostic usefulness of echocardiography in acute rejection is guiding the endomyocardial biopsy. Additionally, echocardiography has found a role as a supplement to invasive angiography in the diagnosis of cardiac allograft vasculopathy.

Unrecognized drug-drug interactions: a cause of intraoperative cardiac arrest?

Many physicians overlook, or are unaware of, most drug-drug interactions. In our patient, the local anesthetic used for an axillary block may have been the precipitating drug in a cascade of drug-drug interactions that resulted in a cardiac arrest. The combination of multiple preoperative drug-drug interactions prevented the return of a stable native cardiac rhythm for almost 24 h. The mechanisms of interactions of these frequently used drugs are described, and the reader is guided to sources that identify and simplify the understanding of potentially dangerous drug-drug interactions.

Computed tomography assessment of valvular morphology, function, and disease.

Recent advancement in computed tomography angiography (CTA) has enabled the noninvasive delineation of cardiac valves using this method. Although echocardiography is the current standard, CTA is a valuable complementary imaging method to evaluate valvular morphology and function. In addition, CTA may contribute to the assessment of both congenital and acquired valvular heart disease, infectious endocarditis, and postsurgical complications of valve replacement.

Pregnancy-associated plasma protein-A: an emerging cardiac biomarker.

Pregnancy associated plasma protein-A (PAPP-A), originally discovered as a glycoprotein found in the serum of pregnant women, is emerging as a potential biomarker of plaque instability. It is produced by the syncytiotrophoblasts of the placenta and circulates in the form of an approximately 500 kDa heterotetramer. In addition, PAPP-A is present in the sera of men and non-pregnant women at much lower levels in the form of a homodimer, and is produced by a number of different non-placental cell types, including fibroblasts, vascular endothelial cells, and vascular smooth muscle cells. The identification of PAPP-A as a member of the metzincin metalloproteinase superfamily, its synthesis by cell types involved in atherogenesis, and its role in insulin-like growth factor-I regulation has led to the hypothesis that PAPP-A is involved in atherosclerotic plaque progression and instability. Serum PAPP-A may be a biomarker for the detection of vulnerable, unstable plaque. Although early reports appear to validate this hypothesis, adoption of PAPP-A as a clinical cardiac biomarker will need assay standardization and further clinical validation. The clinical validation will require a large and diverse patient population, a clearly defined and uniform diagnostic strategy, incorporation of multiple biomarkers in addition to PAPP-A, and measurement of outcomes data.