JAMA : the journal of the American Medical Association
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Randomized Controlled Trial Multicenter Study
Mexiletine for symptoms and signs of myotonia in nondystrophic myotonia: a randomized controlled trial.
Nondystrophic myotonias (NDMs) are rare diseases caused by mutations in skeletal muscle ion channels. Patients experience delayed muscle relaxation causing functionally limiting stiffness and pain. Mexiletine-induced sodium channel blockade reduced myotonia in small studies; however, as is common in rare diseases, larger studies of safety and efficacy have not previously been considered feasible. ⋯ In this preliminary study of patients with NDMs, the use of mexiletine compared with placebo resulted in improved patient-reported stiffness over 4 weeks of treatment, despite some concern about the maintenance of blinding.
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Pulmonary hypertension (PH), defined as elevated pulmonary artery pressure, is common in the general population and associated with increased mortality. Accordingly, physicians commonly encounter patients with dyspnea, exercise intolerance, and/or right heart failure who have elevated pulmonary artery systolic pressure (PASP) on echocardiography. ⋯ Treatment of this more common group of patients with PH due to left heart disease is challenging because there are few evidence-based treatment options, and pulmonary vasodilator therapy may lead to worsening symptoms. Therefore, improving symptoms and avoiding adverse outcomes in patients with PH requires the following: (1) understanding the optimal use of echocardiography for the diagnosis of PH; (2) recognizing the utility and proper interpretation of invasive hemodynamic testing prior to starting pulmonary vasodilator therapy; (3) differentiating PAH from pulmonary venous hypertension due to left heart disease; and (4) understanding the appropriate treatment strategies for PH and resultant right heart failure.