How should persistent dizziness in a pregnant patient be evaluated and managed?

Persistent Dizziness in Pregnancy: Evaluation and Management

Immediate Assessment and Stabilization

Position the patient in left lateral decubitus immediately to relieve inferior vena cava compression, which commonly causes dizziness and bradycardia in pregnancy through supine hypotensive syndrome. 1, 2

• Assess hemodynamic stability first—if the patient is unstable with documented tachycardia or bradycardia, prepare for immediate electrical cardioversion or temporary pacing as maternal stability is paramount for fetal survival. 1, 3, 4
• Check vital signs including heart rate, blood pressure, and oxygen saturation to distinguish between tachyarrhythmia, bradyarrhythmia, or non-cardiac causes. 3, 4

Diagnostic Workup

Cardiac Evaluation

Obtain a 12-lead ECG immediately to document rhythm, identify specific arrhythmia type (SVT occurs in 20-44% of pregnancies), and evaluate for pre-excitation patterns or QT prolongation. 3, 4

• Place a Holter monitor if symptoms are recurrent but not captured on initial ECG, as paroxysmal arrhythmias are common causes of persistent dizziness. 3
• Perform echocardiography to exclude structural heart disease, peripartum cardiomyopathy, or valvular abnormalities—this is essential in any pregnant patient with documented arrhythmia. 3, 4
• Evaluate for conduction abnormalities: first-degree AV block is benign and common in pregnancy without structural disease, while second-degree or complete heart block requires closer monitoring. 1, 2

Vestibular and Neurological Assessment

• Assess for benign paroxysmal positional vertigo (BPPV), vestibular migraine, or Meniere's disease, as these vestibular disorders are frequently exacerbated during pregnancy due to hormonal changes affecting inner ear structures. 5, 6
• Perform targeted neurological examination looking for focal deficits, visual changes, or severe headache that might indicate intracranial pathology (hemorrhage, venous sinus thrombosis, or eclampsia-related complications). 7, 8
• Check for signs of preeclampsia/eclampsia: blood pressure ≥140/90 mmHg after 20 weeks gestation, proteinuria, visual disturbances, or severe headache. 1

Metabolic and Obstetric Evaluation

• Rule out hyperemesis gravidarum with severe dehydration, electrolyte abnormalities, or thiamine deficiency (which can cause Wernicke encephalopathy), especially if accompanied by nausea and vomiting. 9
• Assess for anemia, hypoglycemia, and thyroid dysfunction—common metabolic causes of dizziness in pregnancy. 6
• Perform fetal monitoring to ensure fetal well-being, as maternal arrhythmias can compromise uteroplacental perfusion. 3

Management Based on Etiology

For Documented Supraventricular Tachycardia

Attempt vagal maneuvers first (Valsalva, carotid massage), followed by IV adenosine 6 mg rapid push if vagal maneuvers fail, then IV metoprolol or propranolol as slow infusion if adenosine is ineffective. 1, 3, 4

• For recurrent SVT requiring prophylaxis, prescribe cardioselective beta-blockers (metoprolol 50-100 mg twice daily or propranolol 80-160 mg daily in long-acting formulations) as first-line therapy after the first trimester. 1, 3, 4
• Never use atenolol in pregnancy—it is associated with fetal growth restriction and is contraindicated. 1, 4
• If beta-blockers fail, consider oral digoxin, sotalol, or flecainide as second-line agents. 1, 4
• Do not use AV nodal blocking agents if pre-excitation is present on ECG, as this can precipitate ventricular fibrillation. 1, 4

For Symptomatic Bradycardia

If symptoms persist after left lateral positioning, insert a temporary pacemaker—this is especially indicated during labor and delivery for women with complete heart block who experience syncope or severe bradycardia. 1, 2

• Implant a permanent single-chamber pacemaker for persistent symptomatic bradycardia unresponsive to conservative measures; this can be performed safely after 8 weeks gestation using echocardiographic guidance to minimize fetal radiation exposure. 1, 2
• Isolated congenital complete heart block usually has favorable pregnancy outcomes when the escape rhythm is narrow-QRS, and routine pacing is often unnecessary. 1, 2

For Vestibular Causes

• Treat BPPV with Epley maneuver or vestibular rehabilitation therapy—these are safe and effective in pregnancy. 5, 6
• For vestibular migraine, use paracetamol as first-line acute treatment; NSAIDs (ibuprofen) can be used only during the second trimester. 1
• If preventive therapy is required for frequent vestibular migraine, propranolol is the recommended first choice with the best safety profile in pregnancy. 1

For Metabolic/Obstetric Causes

• Treat hyperemesis gravidarum with IV fluids, electrolyte replacement, and thiamine supplementation (following protocols to prevent refeeding syndrome and Wernicke encephalopathy), plus antiemetics such as metoclopramide or doxylamine/pyridoxine. 9
• Manage preeclampsia/eclampsia according to obstetric protocols with blood pressure control and consideration for delivery timing. 1

Critical Pitfalls to Avoid

Do not postpone essential cardiac interventions due to pregnancy concerns—maternal hemodynamic stability is paramount for fetal survival, and electrical cardioversion is safe at all stages of pregnancy. 2, 3, 4

• Do not assume all dizziness in pregnancy is benign; increased cardiac demand can convert asymptomatic rhythm disturbances into symptomatic ones, and structural heart disease must be excluded. 2, 3
• Avoid overlooking coexisting structural heart disease, especially in patients with repaired congenital lesions (tetralogy of Fallot, VSD repair). 1, 2
• Do not use medications contraindicated in pregnancy: atenolol, amiodarone (except as last resort), ACE inhibitors, ARBs, topiramate, candesartan, or sodium valproate. 1, 3, 4

When to Escalate Care

Refer immediately to the emergency department if the patient experiences recurrent episodes of dizziness with tachycardia, syncope or near-syncope, shortness of breath, chest pain, focal neurological deficits, severe headache, visual changes, or signs of hemodynamic instability. 3, 4

• Continuous fetal monitoring should be employed whenever maternal arrhythmia or significant dizziness is present to detect potential fetal hypoperfusion. 2
• Regular follow-up with both cardiology and obstetrics is essential to monitor maternal symptoms and fetal well-being throughout pregnancy. 3, 4