What are the first-line cardiac tests for positional lightheadedness, also known as orthostatic (Orthostatic Hypotension) dizziness?

From the Guidelines

For positional lightheadedness, the first-line cardiac tests should include an electrocardiogram (ECG), orthostatic vital signs, and basic laboratory work, as recommended by the most recent guidelines 1. The ECG helps identify arrhythmias, conduction abnormalities, or ischemic changes that might cause lightheadedness. Orthostatic vitals, measuring blood pressure and heart rate while lying, sitting, and standing, can detect orthostatic hypotension (a drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing), which is a critical consideration, especially in older patients, where orthostatic hypotension is common and can be exacerbated by certain medications 1. Laboratory tests should include complete blood count to rule out anemia, basic metabolic panel to check electrolytes, and possibly cardiac enzymes if acute cardiac events are suspected. If these initial tests are inconclusive but cardiac causes remain suspected, additional testing may include 24-hour Holter monitoring or event recorders to capture intermittent arrhythmias, echocardiogram to assess structural heart disease, and in some cases, tilt-table testing to evaluate for vasovagal syncope or postural orthostatic tachycardia syndrome (POTS), as suggested by earlier guidelines 1. However, the most recent guideline from 2024 1 emphasizes the importance of considering orthostatic hypotension, particularly in the management of elevated blood pressure and hypertension, highlighting the need for a tailored approach to diagnosis and treatment. Key points to consider in the diagnostic workup include:

• The use of ECG to identify potential cardiac causes
• The measurement of orthostatic vitals to detect orthostatic hypotension
• The consideration of basic laboratory work to rule out other causes of lightheadedness
• The potential need for additional testing, such as Holter monitoring or echocardiogram, based on initial findings and clinical suspicion. Given the emphasis on recent evidence and the importance of orthostatic hypotension in the context of positional lightheadedness, the approach outlined in the 2024 guideline 1 should be prioritized, focusing on thorough initial assessment and tailored further investigation based on patient-specific factors.

From the Research

Positional Lightheadedness and First-Line Cardiac Tests

• Positional lightheadedness, also known as orthostatic hypotension (OH), is a common condition characterized by a sustained reduction in systolic blood pressure > 20 mm Hg or diastolic blood pressure > 10 mm Hg within 3 minutes of standing or > 60° head-up tilt 2, 3.
• The diagnosis of OH requires blood pressure measurements in the supine and standing positions, as well as heart rate responses to standing to assess integrity of baroreflex function 2.
• First-line cardiac tests for positional lightheadedness may include:
  • Blood pressure measurements in different positions (supine, seated, and standing) 2, 3
  • Heart rate monitoring to assess baroreflex function 2
  • Orthostatic challenge to diagnose OH 3, 4
• The treatment of OH should be initiated in a structured and stepwise approach, starting with nonpharmacological interventions (e.g., lifestyle modifications and physical countermanoeuvres) and adding pharmacological interventions as needed in patients with severe OH 2, 4.
• In patients presenting with dizziness, including positional lightheadedness, diagnostic tests should be ordered for those who have abnormal findings on physical examination that may indicate a more serious cause of dizziness 5.