Effect of Ivabradine on Patients With Postural Orthostatic Tachycardia Syndrome

Effect of Ivabradine on Patients With Postural Orthostatic Tachycardia Syndrome (a Double-blind Placebo-parallel Group Trial)

Postural orthostatic tachycardia syndrome (POTS) occurs in approximately 500,000 Americans, but predominates in women with a 5:1 ratio. Patients with POTS experience debilitating tachycardia upon postural changes such as standing that impairs their quality of life. Tachycardia is clinically defined as a heart rate greater than 100 beats/min; and in POTS patients, the prolonged heart rate increase is greater than 30 beats/min or increases to 120 beats/min within the first ten minutes of a diagnostic tilt table test without postural hypotension. There are currently no effective treatment methods for POTS. However, several studies suggest Ivabradine could be a main treatment option for POTS because Ivabradine specifically inhibits the f-channels (If) within the sinoatrial (SA) node, which slows the heart rate. Currently in the US, Ivabradine is mainly prescribed to treat chronic heart failure. It is well tolerated in patients, but it is not commonly prescribed for POTS. It has been also used for treatment of inappropriate sinus tachycardia with good benefit. The hypothesis for this experiment is that Ivabradine will reduce tachycardia and improve functional status in patients with POTS.

Inclusion Criteria:

• Subjects aged 18-65.
• Subjects must have POTS diagnosis (Hyperadrenergic Subtype with NE> 600pg/ml))
• Subjects with no structural heart disease
• Subject with no arrhythmias
• Subjects with norepinephrine levels greater than 600 pg/ml
• Subjects with normal CBC, Metabolic, and thyroid levels

Exclusion Criteria:

• Thyroid or adrenal disorders
• Drugs that interfere with Ivabradine (example: Cytochrome P450 drugs)
• Presentation of peripheral edema and discolored toes with peripheral autonomic neuropathy. Symptoms include: legs (reduced hair growth, cramps), toes (blue color), legs/feet (wounds, ulcers that do not heal), and muscles (numbness, heaviness)
• Subjects who have had a history of systemic illnesses (acute or chronic infectious); autoimmune/ inflammatory disease, cancer, COPD, anemia, diabetes, or psychiatric illness
• Subjects with resting heart rate< 60beats/min, atrial fibrillation, advanced AV blocks, sinus disease, and acute decompensated heart failure and severe hepatic impairment.
• Smokers or alcohol abuse
• Pregnant or breastfeeding mothers
• Woman of childbearing potential who are unwilling to use highly effective contraception during treatment and for an additional one month after discontinuing the study drug