Can premature atrial contractions (PACs) cause dizziness?

Premature Atrial Contractions: Causes and Association with Dizziness

Premature atrial contractions (PACs) can cause dizziness, though this symptom is less common than palpitations, and PACs themselves arise from various triggers including electrolyte abnormalities, stimulants, structural heart disease, and lifestyle factors. 1, 2

What Causes Premature Atrial Contractions

Common Triggers and Risk Factors

• Electrolyte abnormalities (particularly potassium and magnesium disturbances) are reversible causes that should be identified and corrected 2
• Hyperthyroidism represents another reversible metabolic cause requiring evaluation 2
• Stimulant use including caffeine, alcohol, and sympathomimetic drugs can provoke PACs 2
• Poor physical activity is associated with 81% higher odds of frequent PACs compared to ideal physical activity levels 3
• Elevated body mass index (poor BMI category) correlates with 41% higher odds of occasional PACs versus ideal BMI 3

Structural and Pathologic Causes

• Underlying structural heart disease can manifest with PACs, particularly in patients with prior congenital heart surgery or significant hemodynamic abnormalities 4
• Drug-induced causes include medications such as adenosine, theophylline/aminophylline, and various chemotherapeutic agents 1
• Atrial cardiomyopathy may be both a cause and consequence of frequent PACs, representing structural, functional, and biochemical changes in the atria 5

Can PACs Cause Dizziness?

Direct Symptomatic Effects

• Yes, PACs can cause dizziness along with other symptoms including palpitations, fatigue, chest discomfort, dyspnea, lightheadedness, or syncope 4
• The mechanism relates to hemodynamic effects on blood pressure and cardiac output, similar to other arrhythmias 1
• Some patients experience dizziness specifically with PVCs (a related phenomenon), suggesting similar mechanisms may apply to PACs 2

Important Clinical Distinction

• The ACCF/AHA guidelines specifically define syncope as transient loss of consciousness, explicitly stating it is "not light-headedness or dizziness alone" 1
• This distinction is critical: while PACs can cause dizziness, true syncope from PACs alone (in the absence of structural disease) is uncommon and warrants more extensive evaluation

Clinical Approach to PACs with Dizziness

When to Evaluate Further

• Any PAC causing symptoms (including dizziness) warrants diagnostic workup regardless of frequency 4
• Obtain 24-hour Holter monitoring to capture the arrhythmia, quantify burden, and correlate symptoms with PAC occurrence 4
• Echocardiogram should be performed to exclude structural heart disease 2
• Check thyroid function and electrolytes to identify reversible causes 2

Risk Stratification by PAC Burden

• Frequent PACs (>2,000 per 24 hours) require comprehensive evaluation due to substantially increased risk of atrial fibrillation, stroke, and adverse atrial remodeling 4, 5, 6
• Athletes with ≥2 PACs on a single 12-lead ECG should undergo extensive evaluation including Holter monitoring, echocardiogram, and exercise stress testing 4
• In healthy, asymptomatic individuals with isolated PACs, no structural heart disease, and normal thyroid function, no further evaluation or therapy is required 4

Treatment Considerations

• Beta blockers are first-line for symptomatic PACs after reversible causes are eliminated 2
• Catheter ablation may be considered for highly symptomatic patients or those with PAC-induced cardiomyopathy 2, 7
• Lifestyle modification targeting physical activity and BMI may reduce PAC burden, though prospective evidence for this approach is limited 3

Critical Pitfall to Avoid

• Do not dismiss dizziness in patients with frequent PACs as purely benign, as frequent PACs are associated with atrial fibrillation, stroke, and all-cause mortality independent of AF occurrence 5, 6
• The concept of atrial cardiomyopathy suggests PACs may indicate underlying atrial pathology where AF is an epiphenomenon rather than the primary problem 5