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Aims: Myotonic dystrophy type 1 (DM1) predisposes to the development of life-threatening arrhythmias and sudden cardiac death. Our study aimed to evaluate the prognostic value of programmed ventricular stimulation (PVS) in DM1 patients with conduction system disease.Methods and Results: Arrhythmic CArdiac DEath in MYotonic dystrophy type 1 patients (ACADEMY 1) is a double-arm non-randomized interventional prospective study. Myotonic dystrophy type 1 patients with permanent cardiac pacing indication were eligible for the inclusion. The study population underwent to pacemaker (PM) or implantable cardioverter-defibrillator (ICD) implantation according to the inducibility of ventricular tachyarrhythmias at PVS. Primary endpoint of the study was a composite of appropriate ICD therapy and cardiac arrhythmic death. The secondary study endpoint was all-cause mortality. Seventy-two adult-onset DM1 patients (51 ± 12 years; 39 male) were enrolled in the study. A ventricular tachyarrhythmia was induced in 25 patients (34.7%) at PVS (PVS+) who underwent dual chambers ICD implantation. The remaining 47 patients (65.3%) without inducible ventricular tachyarrhythmia (PVS-) were treated with dual-chamber PM. During an average observation period of 44.7 ± 10.2 months, nine patients (12.5%) met the primary endpoint, four in the ICD group (16%) and five (10.6%) in the PM group. Thirteen patients died (18.5%), 2 in the ICD group (8%) and 11 in PM group (23.4%). The Kaplan-Meier analysis did not show a significantly different risk of both primary and secondary endpoint event rates between the two groups.Conclusions: The inducibility of ventricular tachyarrhythmias has shown a limited value in the arrhythmic risk stratification among DM1 patients. [ABSTRACT FROM AUTHOR]

Introduction: Careful, stepwise assessment is required in all patients with atrial septal defect (ASD) to exclude pulmonary vascular or left ventricular (LV) disease. Fluid challenge and balloon occlusion may unmask LV disease and post-capillary pulmonary hypertension, but their role in the evaluation of patients with 'operable' ASDs is not well established.Methods: We conducted a prospective study in three Italian specialist centres between 2018 and 2020. Patients selected for percutaneous ASD closure underwent assessment at baseline and after fluid challenge, balloon occlusion and both.Results: Fifty patients (46 (38.2, 57.8) years, 72% female) were included. All had a shunt fraction >1.5, pulmonary vascular resistance (PVR) <5 Wood Units (WU) and pulmonary arterial wedge pressure (PAWP) <15 mm Hg. Individuals with a PVR ≥2 WU at baseline (higher PVR group) were older, more symptomatic, with a higher baseline systemic vascular resistance (SVR) than the lower PVR group (all p<0.0001). Individuals with a higher PVR experienced smaller increases in pulmonary blood flow following fluid challenge (0.3 (0.1, 0.5) vs 2.0 (1.5, 2.8) L/min, p<0.0001). Balloon occlusion led to a more marked fall in SVR (p<0.0001) and a larger increase in systemic blood flow (p=0.024) in the higher PVR group. No difference was observed in PAWP following fluid challenge and/or balloon occlusion between groups; four (8%) patients reached a PAWP ≥18 mm Hg following the addition of fluid challenge to balloon occlusion testing.Conclusions: In adults with ASD without overt LV disease, even small rises in PVR may have significant implications on cardiovascular haemodynamics. Fluid challenge may provide additional information to balloon occlusion in this setting. [ABSTRACT FROM AUTHOR]

Research suggests that endothelium-dependent vasodilation is impacted by plasma protein ceruloplasmin. Experiments using rabbit aorta rings in the presence of endothelial nitric oxide are described. Vasorelaxation measurements are illustrated for rabbit thoracic aorta tissue in the presence of biochemicals such as acetylcholine and nitroglycerin. Further research is required to define ceruloplasmin's physiological role in greater detail.

The reactive metabolite of oxygen, H2O2, regulates the physiological response of platelets to different stimuli. The complex effects of H2O2 on platelet functions include stimulation and accumulation of thromboxane synthesis by low levels of endogenous H2O2 in response to arachidonic acid. Exposure to larger concentrations of exogenous H2O2 affects platelet aggregation to various agonists by activation of guanylate cyclase and enhanced cGMP levels.

Serotonin appears to be released during coronary angioplasty and may play a part in blood vessel constriction that occurs in the segment of the artery farthest from the surgery site. Coronary angioplasty is a method of dilating a blocked blood vessel in the heart. Serotonin is a blood vessel constrictor found in blood platelets. Blood samples were taken from 15 patients having coronary angioplasty. Seven of the patients also received ketanserin, which inhibits the action of serotonin. Serotonin levels before surgery averaged 2.3 nanograms per milliliter (ng/ml) in the coronary sinus, a venous channel in the heart, and 2.5 ng/ml in the ascending aorta. Serotonin concentrations in the ascending aorta did not change during surgery. However, serotonin levels increased significantly in the coronary sinus. In the patients not treated with ketanserin, dilation of the segment of the artery farthest from the angioplasty site decreased by 23% after five minutes. In those treated with ketanserin, constriction of the arterial segment farthest from the angioplasty site occurred but to a lesser degree than in those patients not given ketanserin.

To investigate a possible role for serotonin, a substance released from platelets (blood cells essential for clotting), in coronary artery disease, seven patients with coronary artery atherosclerosis (narrowing of the arteries because of the deposition of fatty plaque in the lumen) and seven control patients were studied. Under angiographic guidance (in which X-rays are taken of the vessels after a dye is injected), several variables related to blood flow within a coronary artery were measured before and after the infusion of serotonin or ketanserin (a substance that blocks the effects of serotonin by interfering with its molecular receptor). Results showed that the coronary arteries of patients without atherosclerosis responded to serotonin by dilating, with an increase in cross-sectional area of 52 percent at the highest dose. This was associated with a 58 percent increase in the coronary blood flow. However, arteries of patients with atherosclerotic lesions constricted in response to serotonin, decreasing their cross-sectional area by an average of 64 percent. This response was associated with decreased coronary blood flow. Hypotheses are presented concerning the ways these effects might be mediated: data from the ketanserin trials helped determine which subtypes of serotonin receptor mediate the vasodilating and vasoconstrictive effects. It seems likely that vasodilation in the nondiseased arteries is the consequence of type 1 receptor activation, while vasoconstriction in damaged atherosclerotic arteries results from activation of type 2 receptors. One clinical implication of these results is that serotonin and other substances derived from platelets may play a role in some acute coronary ischemic disorders (disorders where the heart does not receive enough blood). Treatment could include drugs that antagonize type 2 serotonin receptors. (Consumer Summary produced by Reliance Medical Information, Inc.)