Optimal choice of prophylactic anticoagulant therapy for nonvalvular atrial fibrillation in the context of COVID-19 pandemic

Already at the very beginning of COVID-19 pandemic, it became known about the key clinical and pathogenetic significance of immunopathological reactions and disorders of hemostasis. Specific coagulopathy, microvascular thromboinflammatory organ damage, macrothrombosis and thromboembolism in the acute period of COVID-19, as well as secondary hemostasis disorders in convalescents, actualize the issues of caring patients with cardiovascular disease. COVID-19 not only increases the risk of thromboembolic events for patients with previously identified arrhythmias, but can also indirectly cause it (as a complication of infection or therapy). The aim of this work was to summarize the data and substantiate the optimal choice of prophylactic anticoagulant therapy for nonvalvular atrial fibrillation during the COVID-19 pandemic. Atrial fibrillation is not only the most common type of supraventricular tachyarrhythmia, but it is also the main underlying cause of more than half of cardioembolic stroke cases, which requires effective thromboprophylaxis. While maintaining the infectious danger for patients, the anticoagulant selection should take into account the possible dysfunctions and drug interactions during the initial infection or reinfection of COVID-19, as well as the possibility of rapid anticoagulant action reverse if surgery is required or bleeding develops. The optimal choice seems to be the use of dabigatran, which is characterized by the best safety profile for hepato- and nephrotoxicity, cytochrome P450-independent metabolism, and the presence of an antidote.

Influence of thyroid-stimulating hormone on the recurrence after radiofrequency ablation for atrial fibrillation

Atrial fibrillation is one of the most common sustained disorders of cardiac rhythm and is associated with an increased risk of mortality, morbidity due to thromboembolic complications, and heart failure. It is important to highlight that the causative factors are vast. It is well-known that thyroid dysfunction has a proarrhythmic effect and increases the risk of cardiovascular disease. Hyperthyroidism or thyrotoxicosis is recognized to be a baseline risk factor for the development of atrial fibrillation. However, the role of hypothyroidism in atrial arrhythmogenesis is less recognized and not fully understood. At the moment radiofrequency catheter ablation is actively used in the treatment of atrial fibrillation, which in most cases has high efficiency and persistent effect. Despite that, the recurrence of supraventricular tachyarrhythmia can be observed in some patients even after radiofrequency cathe­ter ablation. Patients with a history of hypothyroidism or even high-normal thyroid-stimulating hormone levels are more likely to have a recurrence of supraventricular tachyarrhythmia after radiofrequency catheter ablation. Therefore, thyroid-stimulating hormone levels should be determined in patients who have undergone radiofrequency catheter ablation of atrial fibrillation, especially paroxysmal atrial fibrillation. Consequently, it should be noted that the assessment and correction of modifying risk factors before radiofrequency catheter ablation may provide opportunities for future prevention of recurrence of supraventricular paroxysmal arrhythmias, improve the prognosis and overall quality of life in patients of this group. We have demonstrated the clinical case and emphasized the association of high-normal thyroid-stimulating hormone levels with supraventricular tachyarrhythmia recurrence after radiofrequency catheter ablation for atrial fibrillation.

Incessant Automatic Atrial Tachycardia in a Neonate Successfully Treated with Nadolol and Closely Spaced Doses of Flecainide: A Case Report

Supraventricular tachyarrhythmia (SVT) is the most common type of arrhythmia in childhood. Management can be challenging with an associated risk of mortality. A female neonate was diagnosed with episodes of SVT, controlled antenatally with digoxin. Flecainide was commenced prophylactically at birth. Despite treatment, the infant developed a narrow complex tachycardia at 5 days of age. The electrocardiogram features were suggestive of either re-entry tachycardia or of automatic atrial tachycardia (AAT). Following several unsuccessful treatments, a wide complex tachycardia developed. A transesophageal electrophysiological study led to a diagnosis of AAT. Stable sinus rhythm was finally achieved through increasing daily administrations of flecainide up to six times a day, in association with nadolol. The shortening of intervals to this extent has never been reported before and supports the evidence of a personal, age-specific variability in pharmacokinetics of flecainide. Larger studies are needed to better define the appropriate dose and timing of administration.

Incessant Automatic Atrial Tachycardia in a Neonate Successfully Treated with Nadolol and Closely Spaced Doses of Flecainide: A Case Report

Supraventricular tachyarrhythmia (SVT) is the most common type of arrhythmia in childhood. Management can be challenging with an associated risk of mortality. A female neonate was diagnosed with episodes of SVT, controlled antenatally with digoxin. Flecainide was commenced prophylactically at birth. Despite treatment, the infant developed a narrow complex tachycardia at 5 days of age. The electrocardiogram features were suggestive of either re-entry tachycardia or of automatic atrial tachycardia (AAT). Following several unsuccessful treatments, a wide complex tachycardia developed. A transesophageal electrophysiological study led to a diagnosis of AAT. Stable sinus rhythm was finally achieved through increasing daily administrations of flecainide up to six times a day, in association with nadolol. The shortening of intervals to this extent has never been reported before and supports the evidence of a personal, age-specific variability in pharmacokinetics of flecainide. Larger studies are needed to better define the appropriate dose and timing of administration.