Sympathetic Activation and Arrhythmogenesis after Myocardial Infarction: Where Do We Stand?

Myocardial infarction often leads to progressive structural and electrophysiologic remodeling of the left ventricle. Despite the widespread use of β-adrenergic blockade and implantable defibrillators, morbidity and mortality from chronic-phase ventricular tachyarrhythmias remains high, calling for further investigation on the underlying pathophysiology. Histological and functional studies have demonstrated extensive alterations of sympathetic nerve endings at the peri-infarct area and flow-innervation mismatches that create a highly arrhythmogenic milieu. Such accumulated evidence, along with the previously well-documented autonomic dysfunction as an important contributing factor, has stirred intense research interest for pharmacologic and non-pharmacologic neuromodulation in post-infarction heart failure. In this regard, aldosterone inhibitors, sacubitril/valsartan and sodium-glucose cotransporter type 2 inhibitors have shown antiarrhythmic effects. Non-pharmacologic modalities, currently tested in pre-clinical and clinical trials, include transcutaneous vagal stimulation, stellate ganglion modulation and renal sympathetic denervation. In this review, we provide insights on the pathophysiology of ventricular arrhythmogenesis post-myocardial infarction, focusing on sympathetic activation

Treatment of Mobile Right Heart Thrombi

Right heart thrombi are detected in approximately 4% of patients with pulmonary embolism. The associated mortality is high, but the optimal strategy remains controversial. We report a case of a large mobile right heart thrombus, complicated by embolism of the right pulmonary artery, which was successfully treated with half-dose alteplase. We briefly review the literature and discuss the therapeutic options, focusing on the advantages of thrombolysis

Preoperative Diagnosis of Abdominal Extra-Adrenal Paragangliomas with Fine-Needle Biopsy

Paragangliomas are rare, non-epithelial neuroendocrine neoplasms originating in paraganglia, for instance the adrenal medulla, or at extra-adrenal locations. The aim of this study was to review the literature regarding abdominal extra-adrenal paragangliomas diagnosed pre-operatively with fine-needle biopsy (FNA and/or FNB). The PubMed database was searched to identify such cases, using a specific algorithm and inclusion/exclusion criteria. An unpublished case from our practice was also added to the rest of the data, resulting in a total of 36 cases for analysis. Overall, 24 (67%) lesions were found in females, whereas 12 (33%) in males. Most (21/36; 58.33%) were identified around and/or within the pancreatic parenchyma. FNA and/or FNB reached or suggested a paraganglioma diagnosis in 17/36 cases (47.22%). Of the preoperative misdiagnoses, the most common was an epithelial neuroendocrine tumor (NET). Regarding follow-up, most patients were alive with no reported recurrence; however, 5/36 patients exhibited a recurrence or a widespread disease, whereas one patient died 48 months following her diagnosis. In two patients, transient hypertension was reported during the EUS-FNA procedure. In conclusion, this study showed that the preoperative diagnosis of these lesions is feasible and, while diagnostic pitfalls exist, they could significantly be avoided with the application of immunochemistry

The Current Role of Omega-3 Fatty Acids in the Management of Atrial Fibrillation

Background: The main dietary source of omega-3 polyunsaturated fatty acids (n-3 PUFA) is fish, which contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In the present manuscript, we aimed to review the current evidence regarding the clinical role of n-3 PUFA in the prevention of atrial fibrillation (AF) and the possible underlying mechanisms. Methods: A literature search based on PubMed listings was performed using “Omega-3 fatty acids” and “atrial fibrilation” as key search terms. Results: n-3 PUFA have been shown to attenuate structural atrial remodeling, prolong atrial effective refractory period through the prevention of reentry and suppress ectopic firing from pulmonary veins. Dietary fish intake has been found to have no effect on the incidence of AF in the majority of studies. Circulating DHA has been consistently reported to be inversely associated with AF risk, whereas EPA has no such effect. The majority of studies investigating the impact of n-3 PUFA supplementation on the incidence of AF following cardiac surgery reported no benefit, though most of them did not use n-3 PUFA pretreatment for adequate duration. Studies using adequate four-week pretreatment with n-3 PUFA before cardioversion of AF showed a reduction of the AF incidence. Conclusions: Although n-3 PUFA have antiarrhythmogenic properties, their clinical efficacy on the prevention of AF is not consistently supported. Further well-designed studies are needed to overcome the limitations of the existing studies and provide robust conclusions

Carotid Artery Stenting With Proximal Cerebral Protection for Patients With Angiographic Appearance of String Sign

ObjectivesThe aim of this study was to assess the safety and effectiveness of carotid artery stenting (CAS) with proximal cerebral protection in patients showing string sign at carotid angiography.BackgroundPresence of string sign is a well-known factor for adverse events in patients with severe carotid artery disease undergoing CAS.MethodsWe used retrospective analysis of a cohort of patients who underwent carotid angiography with the intention to undergo carotid stenting and had angiographically documented string sign in the target lesion.ResultsFrom October 2006 to August 2007, 25 patients (21 men and 4 women, mean age 70.9 ± 8.7 years) presented with string sign during carotid angiography. This was 6.0% of a total of 416 patients studied during the time of the study. Twenty patients (80.0%) were symptomatic, and 5 (20.0%) were asymptomatic. Carotid artery stenting was performed successively in all patients. Proximal cerebral protection was applied in all but 1 patient. The 30-day death/stroke rate was 0%. At 12-month follow-up neurological events did not occur; 1 patient developed a nonfatal myocardial infarction, and another patient died from noncardiac cause. The 12-month death/stroke rate was 4.0%.ConclusionsCarotid stenting under proximal cerebral protection seems to be a feasible and safe procedure to manage patients with severe carotid stenosis in presence of angiographic string sign. Further prospective trials are required to prove efficacy of CAS in larger study populations

Effect of intravenous administration of antioxidants alone and in combination on myocardial reperfusion injury in an experimental pig model

AbstractBackground: Several antioxidants have been found to have conflicting results in attenuating myocardial reperfusion injury. These studies were done primarily in experimental protocols that did not approximate clinical situations.Objective: The aim of this study was to test the efficacy of 3 different antioxidants (ascorbic acid [AA], desferrioxamine, and N-acetylcysteine [NAC]) administered IV alone and in combination in a closed-chest pig model.Methods: Farm-raised domestic male pigs (aged 3–5 months, weight of 30–35 kg) were assigned to 1 of 5 groups to receive treatment as follows: group A, AA 100 mg/kg; group B, desferrioxamine 60 mg/kg; group C, a loading dose of NAC 100 mg/kg for 20 minutes and a 20-mg/kg maintenance dose; group D, all 3 drugs in combination; and group E, normal saline (control group). The infusion of all drugs was started 15 minutes before and completed 5 minutes after reperfusion, except for the administration of NAC, which was terminated 60 minutes postreperfusion. Myocardial ischemia (45 minutes) and reperfusion (210 minutes) were achieved percutaneously by circumflex artery balloon occlusion. Ejection fraction, left ventricular end-diastolic pressure (LVEDP), flow in the infarcted artery, and all ventricular arrhythmias were recorded. Oxidative stress was estimated by serial measurements of thiobarbituric acid reactive substance (TBARS) concentration in coronary sinus blood. Infarct size was assessed as a percentage of the area at risk (I/R ratio) using the tetrazolium red staining method.Results: The 25 pigs were divided into 5 groups of 5 pigs each. No significant between-group differences were found in I/R ratio or in oxidative stress (as measured by TBARS concentration). Group C developed significantly more ventricular atrhythmias than the control group (80% vs 0%, P = 0.02). No other differences among groups were found. LVEDP was significantly elevated in all treatment groups (mean LVEDP difference [SD] for group A, 6.0 [1.6] mm Hg; group B, 17.6 [1.9] mm Hg; group C, 3.6 [1.7] mm Hg; group D, 6.8 [3.2] and group E, 5.4 [3.4] mm Hg). LVEDP elevation was found to be significantly higher in group B compared with all the other groups (all, P < 0.001). No significant between-group differences were found in the other parameters measured.Conclusion: In this experimental pig model, the antioxidants AA, desferrioxamine, and NAC administered alone or in combination did not reduce the deleterious effects of reperfusion injury and specifically the extent of myocardial necrosis