Potential Biomarkers in Atrial Fibrillation: Insight Into Their Clinical Significance.

ABSTRACT: In risk-stratifying patients with atrial fibrillation (AF), physicians rely heavily on clinical parameters that provide risk scores and determine treatment strategies. There has been increasing research on potential biomarkers in the blood that could more accurately determine both risk of complications in AF and risk of incidence of AF. This review highlights the clinical significance of 5 novel biomarkers that have been shown to be linked to AF. These biomarkers are carbohydrate antigen 125, galectin-3, growth differentiation factor-15, a member of the interleukin 1 receptor family, IL1RL1 (ST2), and N-terminal pro B-type natriuretic peptide.

Arrhythmias in Neonates and Infants at a Tertiary Care Center.

Background Limited data about arrhythmias in neonates and infants are coming out from the Middle East. Objectives To evaluate different types of arrhythmias in neonates and infants at the American University of Beirut Medical Center (AUBMC), a tertiary care center in Lebanon, with the focus on the nature of arrhythmia, treatment modalities and relation to surgery. Methods Data were collected retrospectively from the hospital records. We included all neonates and infants presenting to AUBMC between 2013 and 2017. Collected data included: the type of arrhythmia, the treatment modality used and its success, the need for additional modes of treatment, the relationship to congenital heart diseases, and the cardiac surgeries performed. Results Of 16,346 subjects admitted to AUBMC between 2013 and 2017, 90 subjects developed arrhythmias that required medical intervention. The most frequent types of arrhythmias were supraventricular tachycardia (62.22%), junctional ectopic tachycardia (13.33%), complete heart block (7.78%), atrial flutter (5.56%), multifocal atrial tachycardia (3.33%), Wolf Parkinson White Syndrome (3.33%), non-sustained ventricular tachycardia (2.22%), sinus pause (1.11%), and premature ventricular contractions (1.11%). Bivariate analysis showed a significant difference between arrhythmias not related to cardiac surgery and arrhythmias related to cardiac surgery in terms of the type of arrhythmia developed, the presence of congenital heart defect, prematurity, and electrolyte disturbances (P-value <0.005). However, multivariate logistic regression showed no significant difference between the two groups after adjustment for the significant variables (P-value > 0.05). Conclusion There is a significant difference between arrhythmias not related to cardiac surgery and arrhythmias related to cardiac surgery in neonates and infants at AUBMC. However, the difference disappears after adjusting for different variables.

Nonbacterial Thrombotic Endocarditis and Widespread Skin Necrosis in Newly Diagnosed Lung Adenocarcinoma.

Nonbacterial thrombotic endocarditis (NBTE) is a rare entity most commonly diagnosed postmortem with rates in autopsy series ranging from 0.9 to 1.6%. A 63-year-old female with past medical history of hypertension and mitral valve prolapse presented to the hospital with shortness of breath, headache, and necrotic skin lesions on her hands and feet. Computed tomography (CT) scan of her chest demonstrated a pulmonary embolus in the right lower lung segmental artery and right upper lobe lobar to segmental pulmonary artery, a mass-like consolidation in the left upper lung field impeding the hilum. CT scan of the abdomen demonstrated metastatic disease in liver and bone and bilateral femoral deep vein thrombosis. Transesophageal echocardiography revealed severe mitral regurgitation with two small mobile plaques on the mitral valve and two immobile plaques on the descending aorta. Magnetic resonance imaging of the brain was consistent with subacute infarcts and metastatic disease. Bronchoscopy was performed and pathology revealed primary adenocarcinoma of the lung. She was treated with anticoagulation and systemic chemotherapy. The patient and family elected to proceed with hospice due to her clinical decline, poor performance status, and poor prognosis after a prolonged hospital stay. Underlying malignancy is detected in approximately 40-85% of patients with NBTE. Lung cancer is the most frequently associated malignancy followed by pancreatic, stomach, breast, and ovarian cancer. Widespread necrotic skin lesions as presenting symptoms of primary lung adenocarcinoma are rare. In the present case, the diagnosis of necrotic skin lesions and NBTE preceded that of the neoplastic disease. Necrotic skin lesions and NBTE can be the first manifestations of an occult malignancy causing extensive multi-organ infarcts. NBTE can present with such extensive skin lesions as a first presenting sign of malignancy. To the best of our knowledge, this is the first case to present with such extensive skin lesions as the first presenting symptom of lung adenocarcinoma.

Noninvasive Cardioablation.

Stereotactic body radiotherapy uses the principle of 3-dimensional localization of a target to deliver a high dose of radiation to a precise location. The aim of this technique is to ablate tissue noninvasively. Because of its high precision and target conformity, it can deliver a high dose of radiation to a specific area in a tissue without significantly affecting nearby tissues. It is being actively studied and even used in therapy for atrial fibrillation and ventricular tachycardia.

Non-familial cardiomyopathies in Lebanon: exome sequencing results for five idiopathic cases.

BACKGROUND: Cardiomyopathies affect more than 0.5% of the general population. They are associated with high risk of sudden cardiac death, which can result from either heart failure or electrical abnormalities. Although different mechanisms underlie the various types of cardiomyopathies, a principal pathology is common to all and is usually at the level of the cardiac muscle. With a relatively high incidence rate in most countries, and a subsequent major health burden on both the families and governments, cardiomyopathies are gaining more attention by researchers and pharmaceutical companies as well as health government bodies. In Lebanon, there is no official data about the spectrum of the diseases in terms of their respective prevalence, clinical, or genetic profiles. METHODS: We used exome sequencing to unravel the genetic basis of idiopathic cases of cardiomyopathies in Lebanon, a relatively small country with high rates of consanguineous marriages. RESULTS: Five cases were diagnosed with different forms of cardiomyopathies, and exome sequencing revealed the presence of already documented or novel mutations in known genes in three cases: LMNA for an Emery Dreifuss Muscular Dystrophy case, PKP2 for an arrhythmogenic right ventricle dysplasia case, and MYPN for a dilated cardiomyopathy case. Interestingly two brothers with hypertrophic cardiomyopathy have a novel missense variation in NPR1, the gene encoding the natriuretic peptides receptor type I, not reported previously to be causing cardiomyopathies. CONCLUSION: Our results unravel novel mutations in known genes implicated in cardiomyopathies in Lebanon. Changes in clinical management however, require genetic profiling of a larger cohort of patients.

Genetics of Atrial Fibrillation.

Background Atrial fibrillation ( AF ) is a common arrhythmia seen in clinical practice. Occasionally, no common risk factors are present in patients with this arrhythmia. This suggests the potential underlying role of genetic factors associated with predisposition to developing AF . Methods and Results We conducted a comprehensive review of the literature through large online libraries, including PubMed. Many different potassium and sodium channel mutations have been discussed in their relation to AF . There have also been non-ion channel mutations that have been linked to AF . Genome-wide association studies have helped in identifying potential links between single-nucleotide polymorphisms and AF . Ancestry studies have also highlighted a role of genetics in AF . Blacks with a higher percentage of European ancestry are at higher risk of developing AF . The emerging field of ablatogenomics involves the use of genetic profiles in their relation to recurrence of AF after catheter ablation. Conclusions The evidence for the underlying role of genetics in AF continues to expand. Ultimately, the role of genetics in risk stratification of AF and its recurrence is of significant interest. No established risk scores that are useful in clinical practice are present to date.

Swine Atrioventricular Node Ablation Using Stereotactic Radiosurgery: Methods and In Vivo Feasibility Investigation for Catheter-Free Ablation of Cardiac Arrhythmias.

BACKGROUND: Linear accelerator-based stereotactic radiosurgery delivered to cardiac arrhythmogenic foci could be a promising catheter-free ablation modality. We tested the feasibility of in vivo atrioventricular (AV) node ablation in swine using stereotactic radiosurgery. METHODS AND RESULTS: Five Large White breed swine (weight 40-75 kg; 4 females) were studied. Single-chamber St Jude pacemakers were implanted in each pig. The pigs were placed under general anesthesia, and coronary/cardiac computed tomography simulation scans were performed to localize the AV node. Cone beam computed tomography was used for target positioning. Stereotactic radiosurgery doses ranging from 35 to 40 Gy were delivered by a linear accelerator to the AV node, and the pigs were followed up with weekly pacemaker interrogations to observe for potential electrocardiographic changes. Once changes were observed, the pigs were euthanized, and pathology specimens of various tissues, including the AV node and tissues surrounding the AV node, were taken to study the effects of radiation. All 5 pigs had disturbances of AV conduction with progressive transition into complete heart block. Macroscopic inspection did not reveal damage to the myocardium, and pigs had preserved systolic function on echocardiography. Immunostaining revealed fibrosis in the target region of the AV node, whereas no fibrosis was detected in the nontargeted regions. CONCLUSIONS: Catheter-free radioablation using linear accelerator-based stereotactic radiosurgery is feasible in an intact swine model.

Intramuscular myxoma of the tibialis anterior muscle First report in the English literature.

Intramuscular myxoma is a rare entity in itself, and while it has been described in several locations in the body, its presence in the tibialis anterior muscle has only been reported once in the literature. In this case report, we present, to our knowledge, the first case of an intramuscular myxoma in the tibialis anterior muscle in the English literature, which was successfully managed with wide surgical resection.