Postural Tachycardia Syndrome

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Chronic orthostatic symptoms with a dramatic rise in heart rate (> 30 bpm) or > 120 bpm on standing (within 10 minutes) with no orthostatic hypotension (frank syncope is rare)

• Evidence of dysautonomia on functional testing

GENERAL CONSIDERATIONS

• May be primary or secondary to another disorder

• Many patients have a dramatic increase in heart rates up to 120–170 bpm within 2–5 minutes of upright tilt

• Many patients may have been previously labeled as suffering from panic attacks or chronic anxiety

• May be familial

• Norepinephrine reuptake transporter protein gene mutation leading to excessive serum epinephrine is identified in familial form

• Autonomic neuropathies and acetylcholine receptor antibodies in the peripheral autonomic ganglia have been seen in postfebrile illness (postviral) postural orthostatic tachycardia syndrome (POTS)

• Possible link between Ehlers-Danlos syndrome III and POTS

• May occur in diabetes mellitus, amyloidosis, sarcoidosis, alcoholism, chemotherapy (particularly with the vinca alkaloids), heavy metal poisoning, Sjögren’s syndrome, and lupus erythematosus

• May occur after pregnancy

• May be a paraneoplastic manifestation

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Exercise intolerance

• Extreme fatigue

• Lightheadedness

• Diminished concentration

• Tremulousness

• Nausea, headache

• Near syncope

• Occasionally syncope

PHYSICAL EXAM FINDINGS

• Generally normal other than orthostatic tachycardia

DIFFERENTIAL DIAGNOSIS

• Prolonged immobilization

• Significant rapid weight loss

• Orthostatic hypotension

• Neurocardiogenic syndrome

• Chronic fatigue syndrome

• Other neuropathies (eg, syringomyelia)

• Supraventricular tachyarrhythmias

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• CBC, basic metabolic panel

• Fasting glucose

• In appropriate situations: serum protein electrophoresis, paraneoplastic panel

• Antinuclear antibody test

ELECTROCARDIOGRAPHY

• Usually normal in supine resting position

IMAGING STUDIES

• Echocardiogram to exclude structural heart disease

DIAGNOSTIC PROCEDURES

• Tilt-table testing shows an excessive increase in heart rate without any or minimal drop in blood pressure

TREATMENT

CARDIOLOGY REFERRAL

• Patients not responding to conservative measures may benefit from cardiac electrophysiology consultation

HOSPITALIZATION CRITERIA

• If there is syncope, brief hospitalization may be required

• POTS generally can be managed as outpatient

MEDICATIONS

• Avoid dehydration, extreme heat, and alcohol consumption

• Elevate head end of the bed to help condition orthostatic stress

• Aerobic exercise and strength training (if deconditioned, consider water exercise)

• Patients’ responses to individual drugs vary substantially

• Combination therapy may be better

• Salt and fluid replacement

• Fludrocortisone 0.2 mg/day PO

• Autonomic agents: alpha₁-adrenergic agonists (midodrine 10 mg 3 times per day), cardioselective beta blockers (metoprolol 50 mg/day)

• Selective serotonin reuptake inhibitor (SSRI) such as paroxetine 20 mg/day

• Epoetin alpha 50–100 U SC ...