Drug treatment of orthostatic hypotension because of autonomic failure or neurocardiogenic syncope

Orthostatic Hypotension: Management of a Complex, But Common, Medical Problem

Orthostatic hypotension (OH), a common, often overlooked, disorder with many causes, is associated with debilitating symptoms, falls, syncope, cognitive impairment, and risk of death. Chronic OH, a cardinal sign of autonomic dysfunction, increases with advancing age and is commonly associated with neurodegenerative and autoimmune diseases, diabetes, hypertension, heart failure, and kidney failure. Management typically involves a multidisciplinary, patient-centered, approach to arrive at an appropriate underlying diagnosis that is causing OH, treating accompanying conditions, and providing individually tailored pharmacological and nonpharmacological treatment. We propose a novel streamlined pathophysiological classification of OH; review the relationship between the cardiovascular disease continuum and OH; discuss OH-mediated end-organ damage; provide diagnostic and therapeutic algorithms to guide clinical decision making and patient care; identify current gaps in knowledge and try to define future research directions. Using a case-based learning approach, specific clinical scenarios are presented highlighting various presentations of OH to provide a practical guide to evaluate and manage patients who have OH.

Association between polymorphisms in the beta2-adrenoceptor gene and migraine in women

OBJECTIVE

To investigate the role of three common polymorphisms in the beta2-adrenoceptor gene in migraine.

BACKGROUND

Migraine has been associated with increased risk of cardiovascular disease and asthma in which beta2-adrenoceptors play an important role; beta-adrenoceptor antagonists are used in migraine prevention. However, the role of variants in the beta2-adrenoceptor gene in migraine is unclear.

METHODS

Association study among 23,753 white women, participating in the Women's Health Study, for whom we had information on migraine at baseline and genotype status of the polymorphisms rs1042713 (Gly16Arg), rs1042714 (Gln27Glu), rs1800888 (Thr164Ile). Migraine was self-reported and we distinguished between any history of migraine, active migraine with and without aura, and prior migraine (history of migraine but not active migraine) in our analyses.

RESULTS

At baseline 4339 women reported any history of migraine. Of these, 3041 had active migraine (1221 migraine with aura, 1820 migraine without aura) and 1298 prior migraine. No migraine was reported by 19,414 women. Genotype- and haplotype-based analyses did not show an association of any of the gene variants tested with any history of migraine. The multivariable-adjusted odds ratios (ORs) (95% confidence intervals) for any history of migraine in the additive model were 1.0 (0.96-1.05) for rs1042713, 1.0 (0.95-1.05) for rs1042714, and 0.84 (0.68-1.05) for rs1800888. In the haplotype analysis the ORs ranged from 0.83 (0.67-1.03) to 1.01 (0.94-1.07) with Gly16-Glu27-Thr164 as the reference. We also did not find associations in the genotype- and haplotype-based analyses within migraine-specific subgroups.

CONCLUSIONS

Our results do not support a role of 3 investigated polymorphisms in the beta2-adrenoceptor gene in migraine pathophysiology.

Current Management of Syncope: Treatment Alternatives

Syncope, defined as a transient loss of consciousness and postural tone with spontaneous recovery and no neurologic sequelae, is among one of the most common causes of consultation with a physician. The diagnostic workup is complex but can be simplified if focused on the underlying condition. Prognosis is highly dependent on the presence or absence of structural heart disease, primarily the presence of cardiomyopathy regardless of etiology, particularly if the left ventricular (LV) function is less than 35%. The diagnostic approach to the patient with recurrent syncope and no structural heart disease is targeted to rule out neurally mediated causes. This approach usually includes a tilt table test (ie, head-up tilt), carotid sinus massage in patients older than 55 years, and an adenosine challenge test in patients who remain with unexplained syncope. Unexplained syncope in patients with reduced LV function (< 35%) may be potentially life-threatening. Infrequent causes of syncope should be sought in younger patients with a family history of sudden cardiac death. Channelopathies such as the long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia are among this variety. Therapy should address the potential mechanism of syncope. In neurally mediated causes, restoration of orthostatic tolerance, primarily by increasing volume during orthostatic stress, is recommended. Physiologic countermaneuvers and increase in salt and water intake are usually the initial therapy. With syncope in patients with an LV dysfunction (< 35%), an ICD is frequently recommended after ruling out common causes of syncope. Syncope in the elderly is usually multifactorial and therapy should include reassessment of multiple medications, which can promote neurally mediated syncope as well as searching for bradycardic causes. Empiric pacing may be used in this complex group of patients.