Disease relevance of Syncope

• BACKGROUND: Orthostatic intolerance is a syndrome characterized by lightheadedness, fatigue, altered mentation, and syncope and associated with postural tachycardia and plasma norepinephrine concentrations that are disproportionately high in relation to sympathetic outflow [1].
• Autosomal dominant long QT syndrome (LQT) is an inherited disorder that causes syncope and sudden death from cardiac arrhythmias [2].
• CONCLUSION: Upright tilt table testing combined with isoproterenol infusion may be useful to distinguish convulsive syncope from epileptic seizures [3].
• Indications for ICD were sudden death in 10 patients, uncontrolled life-threatening ventricular tachycardia in 12, and syncope with cardiomyopathy and familial sudden death in 1 [4].
• METHODS AND RESULTS: In the 20 participating centers, 126 patients with recurrent vasovagal syncope (at least 3 episodes in the last 2 years) and a positive baseline head-up tilt response were randomly assigned to placebo (63 patients) or etilefrine at a dosage of 75 mg/d (63 patients) and were followed up for 1 year or until syncope recurred [5].

Psychiatry related information on Syncope

• BACKGROUND: The RyR2 mutations have been associated with PVA, syncope and sudden death in response to physical or emotional stress [6].
• Other disorders that may superficially mimic epilepsy include transient ischemic attacks, syncope, and transient global amnesia [7].
• Agitation (73), aggression (70), rash (20), hallucinations (13) and abnormal dreams (31 were unlabelled AES while abnormal liver function tests (12), syncope (8), abnormal behaviour (4) and visual disturbance (3) were labelled AES possibly due to mirtazapine use [8].

High impact information on Syncope

• We conclude that an isoproterenol infusion administered in conjunction with the upright-tilt test may be useful for identifying susceptibility to neurally mediated recurrent syncope [9].
• Verapamil, syncope, and hypertrophic obstructive cardiomyopathy [10].
• Transgingival nitrate syncope [11].
• Thymoma-induced syncope [12].
• Of the 52 patients randomized to ODO, 22 (42%) had recurrent syncope within 6 months compared with 16 (33%) of 48 patients in the DDD group [13].

Chemical compound and disease context of Syncope

• Cough syncope treated with a long-term vasoconstrictor [14].
• Eight previously characterized patients with recurrent NMS (five females and three males; 34+/-2 yr) were recruited from the Vanderbilt Syncope Unit and eight age-matched controls underwent initial administration of clonidine (CLO) or yohimbine (YHO) [15].
• Exacerbations of neurally mediated syncope associated with sertraline [16].
• FINDINGS: We calculated risk scores from patients' admission haemoglobin, blood urea, pulse, and systolic blood pressure, as well as presentation with syncope or melaena, and evidence of hepatic disease or cardiac failure [17].
• Induction of neurally mediated syncope with adenosine [18].

Biological context of Syncope

• A homozygous missense mutation, leading to an alanine-to-threonine substitution at the beginning of the pore domain of the KVLQT1 channel, was found in the proband, a 9-year-old boy with normal hearing, a prolonged QT interval, and syncopal episodes during physical exercise [19].
• De Subitaneis Mortibus. XXI. Adult onset syncope. with comments on the nature of congenital heart block and the morphogenesis of the human atrioventricular septal junction [20].
• If presyncope or syncope was not provoked, isoproterenol infusion was started at a rate of 1 microgram/min and the rate gradually increased until a 25% increase in heart rate was achieved [21].
• OBJECTIVES: The purpose of this study was to determine the outcome of patients with nonischemic dilated cardiomyopathy, unexplained syncope and a negative electrophysiology test who are treated with an implantable defibrillator [22].
• After furosemide-induced volume reduction associated with 1.6 +/- 0.2 kg weight loss and approximately 7% blood volume reduction, five of them developed vasodilatory presyncope after 17 +/- 5 min of LBNP [23].

Anatomical context of Syncope

• We hypothesized that an increased susceptibility of the atrioventricular node to adenosine may, in some cases, play a role in the genesis of syncope [24].
• BACKGROUND: The efficacy of sodium chloride and mineralocortoid in the treatment of neurally mediated cardiac syncope is attributed to intravascular volume expansion; however, their modulation of autonomic nervous system activity has not been evaluated [25].
• It is concluded that vasomotor syncope occurs quite frequently in patients with severe chronic heart failure after captopril in a small dose and is associated with a selective increase in epinephrine secretion from the adrenal medulla [26].
• Late-onset drop attacks in temporal lobe epilepsy: a reevaluation of the concept of temporal lobe syncope [27].
• Arrhythmogenic right ventricular disease (ARVD) is a disease of unknown origin that primarily affects the right ventricle and is characterized by ventricular tachyarrhythmias which may lead to syncope and even, though rarely, sudden cardiac death [28].

Gene context of Syncope

• We identified a novel missense mutation, V65 M, in the KCNE2 gene of a 17-year-old female with syncope and LQTS [29].
• This suggested that KCNE1 could be the morbid gene responsible for an autosomal recessive cardio-auditory disease, the Jervell and Lange-Nielsen syndrome, characterized by ventricular repolarization abnormalities and recurrent syncopes leading eventually to sudden death associated with a bilateral congenital deafness [30].
• Conversely, LQT2 patients are at higher risk to develop syncope under stressful conditions, because of the combined arrhythmogenic effect of catecholamines with the insufficient adaptation of their QT interval [31].
• Genotype-negative LQTS patients with a single ANK2 variant displayed nonexertional syncope, U waves, sinus bradycardia, and extracardiac findings [32].
• Among these patients, there is also a trend for LQT2 patients to have syncope or cardiac arrest under emotional or physical stress and for LQT3 patients to have cardiac events either at rest or during sleep [33].

Analytical, diagnostic and therapeutic context of Syncope

• Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians [34].
• The purpose of this study was to determine how to identify patients at high risk of a recurrence of neuromediated syncope after a positive isoproterenol/tilt-table test [35].
• During follow-up, the occurrence of syncope was lower in the pacemaker group than in the control group (P = .02) and tended to be lower than in the theophylline group (P = .07) [36].
• Other clinical populations have been studied, e.g. those with syncope, coronary reperfusion, and cardiomyopathy, with varying degrees of success in predicting ventricular tachycardia [37].
• This was a randomized double-blind crossover study of etilefrine versus placebo in 30 consecutive patients with syncope and a baseline positive head-up tilt test [38].

References