What are the diagnostic criteria for orthostatic (postural) hypotension, and is heart rate (HR) one of them?

Diagnostic Criteria for Orthostatic Hypotension

Orthostatic hypotension is defined as a sustained decrease in systolic blood pressure ≥20 mmHg and/or diastolic blood pressure ≥10 mmHg within 3 minutes of standing from a supine position; heart rate change is NOT one of the diagnostic criteria. 1

Types of Orthostatic Hypotension

1. Classical Orthostatic Hypotension

   • Sustained decrease in systolic BP ≥20 mmHg and/or diastolic BP ≥10 mmHg within 3 minutes of standing
   • OR a sustained decrease in systolic BP to an absolute value <90 mmHg 1

2. Initial (Immediate) Orthostatic Hypotension

   • BP decrease >40 mmHg systolic and/or >20 mmHg diastolic within 15 seconds of standing
   • Spontaneous return to normal within 40 seconds 1

3. Delayed Orthostatic Hypotension

   • Sustained reduction of systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg that takes >3 minutes to develop
   • Often missed with standard 3-minute testing 1

Heart Rate Response in Orthostatic Hypotension

While heart rate changes often occur during orthostatic stress, they are NOT part of the diagnostic criteria for orthostatic hypotension. However, heart rate response can help differentiate between:

• Neurogenic OH: Often shows minimal or absent compensatory heart rate increase due to impaired autonomic function 2
• Non-neurogenic OH: Typically shows preserved heart rate increase as a compensatory mechanism 2

Proper Measurement Technique

For accurate diagnosis, blood pressure should be measured:

• After 5 minutes in the supine position
• At 1 minute after standing
• At 3 minutes after standing
• Consider extended monitoring if delayed OH is suspected 1

Common Pitfalls to Avoid

1. Relying solely on heart rate changes for diagnosis: Heart rate response varies between patients and types of OH, and is not a diagnostic criterion 2

2. Insufficient monitoring time: Delayed OH can be missed if monitoring stops at 3 minutes 1

3. Failure to consider medication effects: Many medications can cause or exacerbate OH 1

4. Not accounting for age-related differences: Prevalence increases with age (5% in middle-aged adults vs. 20% in older adults) 3

5. Missing asymptomatic OH: OH can be present without symptoms but still increases cardiovascular risk 4

Heart rate monitoring during orthostatic testing provides valuable information about autonomic function but is not part of the formal diagnostic criteria for orthostatic hypotension.