No abstract

Background: It is unclear whether the heart is affected in pediatric patients with milder forms of spinal muscular atrophy (SMA). Therefore, we aimed to determine the presence of any cardiac abnormalities in these patients. Methods: We conducted a cross-sectional study of children and adolescents with SMA types 2 and 3 between July 2018 and July 2019. All patients underwent a comprehensive cardiac evaluation, including history-taking, physical examination, electrocardiography, echocardiography, measurement of cardiac biomarkers (cardiac troponin T [cTnT] and N-terminal pro-brain natriuretic peptide [NT-proBNP]), and 24-hour Holter monitoring. Results: In total, 42 patients were enrolled (27 and 15 with SMA type 2 and 3, respectively). No patient had structural heart disease, except for one with mitral valve prolapse. None had signs of ventricular dysfunction on echocardiography. Both cTnT and NT-proBNP levels were normal in all patients. Electrocardiography showed sinus tachycardia in seven patients (16.7%), and prolonged P-R interval in one (2.4%). Holter monitoring detected benign ventricular arrhythmias in two patients (4.8%), and rare supraventricular premature beats in one. The mean 24-hour heart rate was elevated in six patients (14.3%), whereas both the minimum 24-hour heart rate and the maximum R-R interval were increased in 23 (54.8%).

Adenosine produced equi-effective endothelium-independent relaxation of CA in all groups. Pharmacological potency of adenosine was reduced in diabetic animals solely, but even more in diabetic rats submitted to CA occlusion. The enhanced potassium transmembrane flow has certain protective role on adenosine-induced action in occluded CA from non-diabetic rats. Conversely, diabetes solely inhibited adenosine-evoked cascade connected to increased potassium conductance.

Oral propranolol for IHs does not remarkably affect heart rhythm including circadian variations throughout hospital initiation. Therefore, there is no necessity for Holter monitoring in additional safety assessment.

Serotonin is a vasoactive substance that in different blood vessels mostly induces vasoconstriction. Considering the important role of common carotid artery in brain blood supply, the aims of this study were to investigate the effect of serotonin on isolated rat common carotid artery and also to examine participation of intact endothelium, cyclooxygenase products, Ca++ channels and 5-HT2 receptors in serotonin-evoked action. Endothelium was mechanically removed from some vascular rings. Circular artery segments were placed in organ baths containing Krebs–Ringer bicarbonate solution. Cumulative concentration-contraction curves for serotonin were obtained in rings previously equilibrated at basal tone. Serotonin produced concentration-dependent contraction, which was unaltered by endothelial denudation. Serotonin-induced effect was notably and comparably reduced by indomethacin (cyclooxygenase inhibitor) or OKY–046 (thromboxane A2-synthase inhibitor) on intact or denuded rings. Nifedipine (Ca++ channel blocker) or ketanserin (5-HT2 receptor antagonist) strongly reduced serotonin-evoked effect. Our results suggest that serotonin produced concentration-dependent and endothelium-independent contraction of carotid artery, which was initiated by activation of 5-HT2 receptors located on smooth muscle cells and mediated via L-type Ca++ channels. Thromboxane A2 from smooth muscle cells notably contributed to the overall contraction of carotid artery induced by serotonin.