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Sleep is a dynamic and complex process. The stages of sleep, conventionally divided into rapid eye movement (REM) and non-rapid eye movement (non-REM), are characterised by unique autonomic influences over cardiac rhythm and haemodynamics. Non-REM sleep is graded 1–4 according to electroencephalogram (EEG) characteristics and diminished arousability. REM sleep occurs at approximately 90 minute intervals, encompasses most dream activity, and is characterised by rapid eye movements and reduced voluntary muscle activity. Studies of individuals free of cardiac disease show that sinus bradycardia, sinus pauses, and type 1 second degree atrioventricular (AV) block are common during sleep (table 1​1).1 Sinus pauses up to two seconds in duration occur commonly in young people in association with sinus arrhythmia (fig 1​1).1 This is seen more frequently in athletes,w1 and less frequently in those over 80 years of age.w2 These arrhythmias are, for the most part, both asymptomatic and benign. They are a reflection of changes in autonomic tone that occur during sleep and require no intervention unless accompanied by symptoms.2





  1. symptoms

  2. postural tachycardia (>30bpm) within 10minutes

  3. No BP drop (20/10)


  • up to 12 gm daily along with 2-3 L of water

April 30 2017 spoke with Dr Juan Guzman

cardiac rehab (Toronto rehab centre for POTS uses the texas protocol

  • addresses deconditioning using recumbent bike and rowing machines


  • 2.5-5mg bid

  • 'off-label use'

  • 0.05-0.1 mg daily followed by up to 0.3 mg daily

  • preferred administration with hydrocortisone


High Sodium


Low Potassium


  • Chronic primary adrenal insufficiency (physiologic replacement) (off-label dose): Oral: 15 to 25 mg daily in 2 to 3 divided doses. Administer the largest dose in the morning upon awakening, followed by next dose 2 hours after lunch (two-dose regimen) or next dose at lunch, followed by smallest dose in the afternoon no later than 4 to 6 hours before bedtime 

Midodrine (short acting 'pill in a pocket')

  • 2.5-10 mg TID (every 3-4 hrs when upright)

Ivabradine option

  • 'off-label use'

  • 2.5-5-7.5mg bid
















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